Culture in Everyday Life Essay

I experienced culture shock about 7 years ago, when I became friends with a Philippine woman. Her name is Christeen Humangnan; she was born and raised in the Philippines. It wasn’t until Christeen was 14 years old, that she moved to the United States. She would tell me how spoiled we are as Americans. She lived in the Philippines without electricity, a television, and rarely had money for new shoes. Although those customs are different from ours in the United States, there is one culture she practices that stood out. It is called pagmamano. Pagmamano is a Filipino culture that has survived the times and foreign influences. This is the practice of respect by asking for an elder’s hand and touches one’s forehead while bowing. One usually asks by saying â€Å"Mano po.† Mano po translates to â€Å"may I have your hand please.† In return, the elder blesses the person. In the Filipino culture the elderly, refer to parents and grandparents, cousins, or close family friends. It is usually done when one visits a family, when meeting these people outside of the homes or after a religious activity. It is also common to bring children to their godparents during Christmas time to pay respect with this custom. I found this custom in the Filipino culture to be shocking to me because, I have never seen it done before. I also see so many children act disrespectfully to their elders in this country, so it was a blessing in my eyes to see the elderly being respected. Now that I have learned of pagmamano, I participate, and have taught my own children the meaning of this culture. We do not use it in our own culture, but whenever we visit my friend Christeen and her family, we show enough respect to her and her family by participating in pagmamano. I would say that the value assumption was slightly an issue when I first  learned of this practice. I thought to myself, this is not the Philippines, we don’t do that here. After seeing the custom in person and how respectful the adolescents are to their elders, I realized I was wrong. I was happy to learn of it and see the children learning respect. You don’t see many American children show this type of respect. Since cultural relativism supports the theory that there is no absolute right and wrong. Instead, the morals, standards and behaviors that vary among cultures must be taken into consideration. I was wrong to assume that pagmamano should be practiced in the Philippines. I think it is a great way to show respect. At first I thought to myself, that’s weird! Then, I realized that we do â€Å"weird† things too. She considers some of the things we do as â€Å"weird,† when we considered it normal. We just have to accept the fact that we all live together in this country that participates and allows different cultures. I am thankful that I learned of the pagmamano culture, and I respect it.

Effective Communication at the Workplace Essay

Communication is the exchange and flow of information and ideas from one person to another. There are many different reasons for why people communicate, we need communication to express our needs and feelings for example a baby cannot talk to us and tell us what he/she needs so instead he/she would begin to cry to let us know that he/she is due for a feed. Another example would be if a colleague was missing her breaks because there was a staff shortage and she was cross about this, she would then talk to her supervisor and explain her reasons for being cross. Communication is important in a workplace setting because people must interact with one another in ways that will get the job done as quickly and effectively as possible (eNotes. (2013), study smarter). Read more:  Identify the different reasons people communicate  essay Communication is also very important to be able to build new relationships, with that being with the staff or children, if for example there was a fight in the playground which led to some of the children falling out then the staff could arrange some kind of team building activities, to help the children become friends again. Another example would be when the children have just started school or nursery, the staff could sit all the children in a circle and get them to say their names ad one thing they like doing, so the children are aware of others who like to do the same as them. Communication is also important to be able to give and receive information, this could be as simple as sending a letter home with a child to tell their parents about a forth coming event, like a parents evening or if there was a incident in school that the parents of the child would need to be aware off. Or to arrange after school clubs for children and the parents to be able to bond more. Communication is also important when we want to share are thoughts and ideas, for example if in nursery the staff could give the children a piece of paper to write down what they want to do more of then the staff could make an activity based on the children’s ideas. Another example would be if the staff of a setting wanted to involve the parents in after school activities then they could send home a question to ask the parents what they would enjoy doing. Communication is also important the be able to affirm one another, Affirmation is a statement of a positive effect (k.Hoban -2006) this is a good type of communication as it also helps the child’s development. You can use affirmation to make someone feel better about something they’ve done. For example a 9 month year old baby has just said da,da for the first the parents would praise the child by picking them up and hugging them and smiling. Another example would be a simple high five if a young child is doing something right like they have just finished a jigsaw or been to toilet when they needed to go. 1.2 Explain how communication affects relationship in the work setting. In order to work effectively with children, young people and their families, and so that we can plan for and meet their needs in order to do this we need good communication skills. Practitioners who have good communication skills are likely to have stronger relationships with children and their parents. This is because relationships are influenced by the body language, facial expression and ways in which others listen and talk to you. (Tassoni,2012) Without communication in the workplace there would be no good relationships, without relationships I the workplace there will be no trust so any relationships would break down leading to conflict and the staff possibly leaving a bad influence on the children. Also peoples personalities can affect relationships in the workplace because for example say someone has a really bubbly personalities, and someone else is quite shy then that might be intimidating meaning that the shy person may not want to express any ideas they have, leading to them not being as involved as they would like to be. With good communication skills we will find that people will have more of a positive attitude which will make others be more positive around them, creating a positive vibe throughout the workplace, it can also lead to stronger teamwork which will build trust, And then with the children if you show that you care, for example just listening to them talk, then the child will feel more attached to you meaning they will come to you with any concerns.

Koran as a Message of Peace Essay Example | Topics and Well Written Essays - 750 words - 1

Koran as a Message of Peace - Essay Example Not only this that the diction and mythology narrated in these Scriptures are very similar to one another, but also they also lay stress upon one and the same teachings. Since it gives glad tidings to the humans in the afterlife on performing good,  escaping evil, and complying with the commands of Almighty Allah and his last Prophet Hazrat Muhammad (peace and blessings of Almighty Allah be upon him) during their stay in this world. Moreover, its teachings vehemently forbid its followers from hurting, harming and killing anyone, either Muslim or non-Muslim altogether, without any just reason. Similarly, it also provides complete shelter and protection to the non-believers even, which do not have any nefarious designs to harm the Muslims or the cause of Islam, as Chapter 65 Verse 2 of the Scripture clearly states: And whosoever fears Allah and keeps his duty to Him, He will make a way for him to get out (of every difficulty). It is, therefore, Koran is regarded as the message of pea ce. Koran and Bible maintain several issues and beliefs in common. For instance, Leviticus 19: 1-33 of the Hebrew Bible manifestly commands its followers (as well as all humans at large) to worship One God, respect the parents, observe honesty, integrity, chastity and avoid fornication, theft, cheating, adultery, homosexuality and disobedience of God. Almost the same teachings have been stressed in Chapter 17 of the Holy Koran (i.e. Children of Israel), where its verses from 41 to 52 glorify the attributes and blessings of Almighty Allah upon all the creatures, which in return say His hymns and praises subsequently.

Read and answer question Essay Example | Topics and Well Written Essays - 250 words - 4

Read and answer question - Essay Example The evidence is from the text where employees are received from high school and are trained. Due to the performance, others get promotions. The organization has succeeded mainly due to its structure. Each section of the organization has to work to the optimum to maximize the production. There is a well-set communication system, where employees are able to air their grievances and get the appropriate feedback. The piece rate system can also contribute to more production. Here, the workers are paid based on their input. Therefore, they work harder in order to get more money, and in the process, the company enjoys increased productivity. 3. What is the problem of transporting of Lincoln’s control system to other cultures? What suggestion could you make to Lincoln’s managers to increase the future international manufacturing plants more successful? There is a problem of transporting Lincoln’s idea to other national cultures, as the people are not used to the piece rate system. Most of the companies pay their employees according to the number of days that they have worked. Others find it difficult to give bonuses because they view it as a way in which the company makes losses. The idea of borrowing money to pay their workers is not a good idea. This is because as you borrow in the end, there is a need to pay back the money. Therefore, what they should employ is the piece rate system in the US, as the workers will struggle to work harder in to get more salary, enabling the organization to grow further hence reducing loss

Obstructive Uropathy and Myocardial Infarction Essay

Obstructive Uropathy and Myocardial Infarction - Essay Example Obstruction to urine flow can result from intrinsic or extrinsic mechanical blockade as well as from functional defects not associated with fixed occlusion of the urinary drainage system. Mechanical obstruction can occur at any level of the urinary tract, from the renal calyces to the external urethral meatus. Normal points of narrowing, such as the ureteropelvic and ureterovesical junctions, bladder neck, and urethral meatus, are common sites of obstruction. When blockage is above the level of the urinary bladder, unilateral dilatation of the ureter or hydroureter and renal pyelocalyceal system or hydronephrosis, occur; whereas, lesions at or below the level of the bladder cause bilateral involvement. While obstructive uropathy can occur in all age groups, in relation to the following case study that is about a 77-year-old patient, not all the causes are relevant. Bladder dysfunction may be secondary to bladder neck obstruction. In adults, urinary tract obstruction is due mainly to acquired defects; pelvic tumors, calculi, and urethral stricture predominate. Schistosoma haematobium and genitourinary tuberculosis are infectious causes of ureteral obstruction. Obstructive uropathy may also result from extrinsic neoplastic or inflmmatory disorder (Goldfarb, S., 2008). Pathophysiology: Myocardial infarction generally occurs when coronary blood flow decreases abruptly after a thrombotic occlusion of a coronary artery previously affected by atherosclerosis. Slowly developing, high-grade coronary artery stenoses do not usually precipitate myocardial infarction (MI) because of the development of a rich collateral network over time. Instead, MI occurs when a coronary artery thrombus develops rapidly at a site of vascular injury. This injury is produced or facilitated by factors such as cigarette smoking, hypertension, and lipid accumulation. In most cases, infarction occurs when an atherosclerotic plaque fissures, ruptures, or ulcerates and when conditions favor thrombogenesis, so that a mural thrombus forms at the site of rupture and leads to coronary artery occlusion. Histologic studies indicate that the coronary plaques prone to rupture are those with a rich lipid core and a thin fibrous cap. Myocardial infarction is defined as the death of heart mu scle resulting from severe, prolonged ischemia. It usually involves the left ventricle. Most MIs are confined to the distribution of a single coronary artery and are designated as anterior, anteroseptal, lateral, and posteroinferior. Multiregional infarcts also occur. Myocardial infarctions are designated as subendocardial or non-Q-wave when the necrosis is limited to the inner half of the ventricular wall or transmural or Q-wave when the necrosis involves not only the inner half but significant amounts of the outer half of the ventricular wall. The electrocardiographic (ECG) correlates are the ST segment elevation with Q-wave pattern for transmural infarcts and the ST segment depression without Q-wave pattern for subendocardial infarcts. If it is a thrombus, the thrombus typically involves the major coronary artery in the distribution of the infarcted myocardium (K/DOQI, 2004). Subendocardial MI without occlusive thrombosis is related to the influence of other factors,

Online learning of Arabic language Essay Example | Topics and Well Written Essays - 3000 words

Online learning of Arabic language - Essay Example A review of relevant literature related to the problem area to identify various tools and methods that were used follows. This equips the developer with various methodologies to choose from for use in the project. A methodologies section follows suit to explain how waterfall methodologies is instrumental to the realisation of the project goals. At the end of this report, useful recommendations from the whole research are made to ensure smooth creation of the project. ... This has amplified the demand for people to learn and know other languages that they never knew from the start. In the past years, there has been an increase in the number of individuals engrossed in the knowledge of Arabic language. This can be pointed towards the increased trade between the western world and the Middle East. Many English speaking populace would like to know Arabic and communicate with the people from the Middle East effectively (Gleick, 1992). This is a project report absorbed on the online language learning project that I would like to create. I would like to build an online language learning website that would provide various English users with the essential tools for learning Arabic. However to start this project, a lot of literature on the issue is necessary to ensure that there is a correct understanding of the subject area. To start the project, it is necessary to follow all the steps in the system development life cycle. First of all, it was necessary to fir st start with the requirements analysis. During the analysis stage, several online language learning websites were used to know the user requirements necessary for the completion of the project. Searching for related literature to the subject was done through the use of Google search engine. The search was a success and yielded many literature related to the subject. However, only 10 of the literature which comprised mainly of peer reviewed articles were used. The articles were chosen based on their relevance to the topic of discussion and how effective they were to the realisation of the final project. To know the best methodologies to use in the report, it was necessary to look at all the methodologies that were available for use and choose the most

Sex Education Essay Example | Topics and Well Written Essays - 1000 words - 1

Sex Education - Essay Example er elements might need to be taught in future sexual education courses, Grace pointed to the fact that it could be potentially beneficial to integrate students with an understanding of Planned Parenthood or means by which many government and/or state sponsored programs seek to speak to the unique needs of the individual student. Ultimately, Grace described the sexual education course that she took part in as a useful and formative part of her early development (Scholz, 2013). Moreover, she indicated that with regards to speaking with parents concerning sexual topics, the interviewee noted that they had a very open and honest dialogue concerning such matters that began as early as late middle school and/or early high school. Conversely, the second individual who is interviewed, Priscilla Yua, noted that her sexual education class left much to be desired. Ultimately, with regards to the first question posed to the interviewee, the respondent noted that the sexual education course never seemed to deal with the realistic situations in which the student may very well face within their sexual growth and development; instead, it focused upon the grotesque, abnormal, and obscene. She noted that this was likely done as a means of horrifying the student from even considering any type of sexual intercourse for fear that they too might be irrevocably harmed. Similarly, with regards to what she most disliked about the program, Priscilla noted that it was the adolescent and juvenile behavior of the participants the most to the way from the experience (Yua, 2013). Likewise, with regards to what level of improvements could be offered, Priscilla indicated that transitioning sexual education to high school might necessarily benefit the individual due to the fact that they could take the... This paper approves that the fact that since individuals develop and mature at different rates, it is seemingly preposterous to assume that they should be taught extraordinarily personal and intimate details concerning human sexual development as a time in which they are ultimately upon different emotional and mental maturity platforms. By the way, sexual education is currently evidenced within the system that each and every stakeholder is satisfied with the level and extent to which key issues concerning sexual development have been covered and/or presented. Sexual education is begun within the elementary school and continues in the various means up until high school. This essay amkes a conclusion that it was the understanding of this interviewer that there was a clear level of correlation between those interviewees that had not discussed sexual topics with their parents/had not received formal sexual training, and those respondents that spoke unfavorably concerning the existence of sexual education or the net benefit they received while in public school. Although it cannot be inferred that the two this level of correlation there exists a definitive realization based upon us, it should be understood that is very likely that sexual attitudes, first evidenced within the family, transcend into the classroom and directly affect the overall level and extent to which be participant can hope to gain value such discussions.

Process Centred Management Essay Example | Topics and Well Written Essays - 2250 words

Process Centred Management - Essay Example Reengineering changes production from a skill specific departmental process to a product centred approach that looks at the end product and the team effort required to create it. 2. The Building Blocks. The organizational structure may need to change or adjust to cross-departmental communications to support the process centred management approach. The change will require organization around outcomes rather than organization by tasks. In some cases customers may be able to complete part of the process thus eliminating a cost of or required personnel (not too popular among staff because it could cause lay-offs). This could take the form of automated ordering processes via the internet verses a call centre based ordering system. The organization must be prepared for flexibility and change and can do this by devising a strategy to support the change while supporting the workforce who will implement the change. 3. Impact on the organization. Change rarely comes easy and change to a process centred management system is no exception. Change impacts production, employees, management, and the organizational structure. Change is most often designed to cut costs and to increase profits. Employees are the ones that seem to be affected the most by change in management systems. Change from a skills or department approach to a process centred outcome approach may not come easily if it means a reduction in force (lay offs). Ownership of the change makes the change a whole lot easier. The employees will need to adjust to working toward an outcome (process) instead of a single task. This requires adopting a team approach and requires the employees to learn a whole process rather than a step in the process. Job design, job enlargement, and job enrichment all impact the worker. In short, the job gets harder and the employee needs to know and learn more. The employee transitions from worker to professional. Information sharing is a very important part of process centred management. Information can be shared by different team members instead of one department gathering information to pass on to another department for processing. Jobs and job descriptions will need to be reengineered to support the process centred approach. The decision point may need to shift in the organization from higher management down to where the decisions are implemented. Performance measurement is vital to successful process centred management because "measurement is the foundation of improvement2". Quality Assurance (QA) provides the opportunity to correct or confirm product quality and marketability. "What isn't measured doesn't happen because there is no incentive, knowledge, or ownership"(PPT06, Provided with Course). Quality assurance makes sure that the end product meets or exceeds customer satisfaction (demand). "QA in a process centred organization is measure by results, growth, and performance"3. A QA method that organizations can use is Plan, Do, Check, Act (PDCA)4 to ensure that organizational activities support the process centred management approach and thus support production and marketing activities. 4. Changes required in organizational structure. Of all the changes necessary when a switch to process centred management is adopted the change in organization structure will effect the organization the most. The "whose in charge" idea needs to change. Decision making power

How to Make Curry Rice Essay Example for Free

How to Make Curry Rice Essay Do you like curry rice? Curry rice is the food originated in India. Now, curry rice is popular in Japanese homes. Japanese eat curry rice once a week. Curry rice is easy to make and contains a variety of nutrients. It’s not difficult to make curry rice if you follow these three steps; cut the ingredients, fry the ingredients, boil the ingredients. You need four ingredients to make curry rice: potato, carrot, onion, beef. Curry rice is cooked with these ingredients and a pan. Various spices are used to curry. For example, all spice, cardamom, cumin, and so on. Each spice has a role to bring out the flavor of curry. For example, all spice flavor bittersweet taste. Cardamom perfume refreshing fragrance with a strong to curry. These spices are the source of the taste of curry. It is the origin of the pungent condiment. Ingredients and spices are mixed well, and then curry rice becomes good taste. The first step in the process of making curry rice is to cut the ingredients. First, peel the vegetables. And then, cut to the size of the bite-sized vegetables. At that time you had better put potatoes in water to remove excess potato starch. The next step in the process of making curry rice is to fry the ingredients in the pan. In this step, put oil to pan. At the same time you should heat the pan. After that you should add the ingredients and condiment to it. By adding condiment ingredients are seasoned related to basic. The last step in the process of making curry rice is boiling well the ingredients in the pan. After frying the ingredients pour water to the pan and boil well until the ingredients become soft. Then add curry sauce to the pan. At this point you should mix ingredients that are in the pot with a ladle. If you want to make it more delicious, you had better add honey to it. When you finish these steps, serve on a plate curry rice. As you can see, making curry rice is easy. Curry rice is wonderful cooking which contains various nutrients. By following these steps, you can make curry rice easily.

Discussion Bill of Rights Essay Example for Free

Discussion Bill of Rights Essay The Bill of Rights is the collective name for the first ten amendments to the United States Constitution. The Bill of Rights lists freedoms not specifically identified in the main body of the Constitution. These freedoms are freedom of religion, freedom of speech, a free press, and free assembly; the right to keep and bear arms; freedom from unreasonable search and seizure, security in personal effects, and freedom from warrants issued without probable cause; indictment by a grand jury for any capital or infamous crime; guarantee of a speedy, public trial with an impartial jury; and prohibition of double jeopardy. In addition, the Bill of Rights reserves for the people any rights not specifically mentioned in the Constitution and reserves all powers not specifically granted to the federal government to the people or the States. Originally the amendments applied only to the federal government, however, most were subsequently applied to the government of each state by way of the Fourteenth Amendment, through a process known as incorporation. On June 8, 1789 Representative James Madison introduced a series of thirty-nine amendments to the constitution in the House of Representatives. Among his recommendations Madison proposed opening up the Constitution and inserting specific rights limiting the power of Congress in Article One, Section 9. Seven of these limitations would became part of the ten ratified Bill of Rights amendments. Ultimately, on September 25, 1789, Congress approved twelve articles of amendment to the Constitution and submitted them to the states for ratification. Contrary to Madisons original proposal that the articles be incorporated into the main body of the Constitution, they were proposed as supplemental additions to it. On December 15, 1791, Articles Three–Twelve, having been ratified by the required number of states, became Amendments One–Ten of the Constitution. The Bill of Rights has had much judicial impact for 150 years of its  existence, but was the basis for many Supreme Court decisions of the 20th and 21st centuries. One of the first fourteen copies of the Bill of Rights is on public display at the National Archives in Washington, D.C.

Mobile Ad Hoc Networks (MANETs)

Mobile Ad Hoc Networks (MANETs) Introduction What is Mobile Ad Hoc Network? With rapid development of wireless technology, the Mobile Ad Hoc Network (MANET) has emerged as a new type of wireless network. MANET is a collection of wireless mobile nodes (e.g. laptops) that dynamically function as a network without the use of any existing infrastructure and centralized administration. It is an autonomous system where each node operates not only as an end system but also as a router to forward packets for other nodes. Since the nodes in MANET move around, the wireless links break and re-establish frequently. Furthermore, most of mobile nodes are resource limited in computing capability and battery power and therefore traditional computing content routing protocols are not suitable for MANET. Several ad hoc routing protocols have been proposed for each node acting as router and maintaining routing information. There are many other applications of MANET. For examples, MANET can be used to provide emergency Services when the network is impaired due to the damaging of existing infrastructure [8]. Computer scientists have predicted a world of ubiquitous computing in which computers will be all around us, constantly performing mundane tasks to make our lives a little easier. These ubiquitous computers connect in mobile ad hoc mode and change the environment or react to the change of the environment where they are suited. MANET is also found useful in the so-called sensor dust network to coordinate the activities and reports of a large collection of tiny sensor devices which could offer detailed information about terrain or environmental dangerous conditions. Problem Statement and Motivation Most current ad hoc routing protocols assume that the wireless network is benign and every node in the network strictly follows the routing behavior and is willing to forward packets for other nodes. Most of these protocols cope well with the dynamically changing topology. However, they do not address the problems when misbehavior nodes present in the network.A commonly observed misbehavior is packet dropping. In a practical MANET, most devices have very limited computing and battery power while packet forwarding consumes a lot of such resources. Thus some of the mobile devices would not like to forward the packets for the benefit of others and they drop packets not destined to them. On the other hand, they still make use of other nodes to forward packets that they originate. These misbehaved nodes are very difficult to identify because we cannot tell that whether the packets are dropped intentionally by the misbehaved nodes or dropped due to the node having moved out of transmission range or other link error. Packet drop significantly decreases the network performance.Traditional security mechanisms are generally not suitable for MANET because: The network lacks central infrastructure to apply traditional security mechanism such as access control, authentication and trusted third party. Limited bandwidth, battery lifetime, and computation power prohibits the deployment of complex routing protocols or encryption algorithms. New security models or mechanisms suitable for MANET must be found. Network topologies and memberships are constantly changing. Thus new intrusion detection system and entity recognition mechanisms that are suitable for mobile ad hoc networks must be designed to avoid or mitigate the behavior to the networks. Trust management systems have been recently introduced as a security mechanism in MANET. In a trust management system, a communicating entity collects evidence regarding competence, honesty or security of other network participants with the purpose of making assessment or decisions regarding their trust relationships. Here trust Objective and Sub-tasks means the confidence of an entity on another entity based on the expectation that the other entity will perform a particular action important to the trustor, irrespective of the ability to monitor or control that other entity . For example, a trust-based routing protocol can collect the evidence of nodes misbehaving, form trust values of the nodes and select safest routes based on the trust metrics.Reputations systems are often seen as a derivation of trust management system. In the reputation system, an entity forms its trust on another entity based not only on the selfobserved evidence but also on the second hand information from third parties. One of the influential reputation systems is the DSR protocol. In the trust management system, reputation system and other trust-based systems, route selection is based on the sending nodes prior experience with other nodes in the network. Its opinions about how other entities are honest are constantly changing. Thus, we call the trust manag ement systems and their derivations as dynamic feedback mechanisms. The dynamic feedback mechanisms are usually applied on the current ad hoc routing protocols to rate the trust about other nodes in the network and make routing decisions based on the trust matrix, which is formed according to the evidence collected from previous interactions. By incorporating the dynamic feedback mechanism in the routing protocol, misbehaved nodes are identified and avoided to forward packets. In this way,misbehavior can be mitigated. Objective and Sub-tasks The primary objective of this thesis is to Investigate the state of the art of dynamic feedback mechanisms and protocols analyze, implement and evaluate DSR protocols to see how it improves the network performance and what are the side effects of introducing the mechanism to the mobile ad hoc network. Following tasks must be done to achieve the primary objective. Study the preliminary knowledge that is required to carry out the main tasks. For example, to understand DSR protocol one must have some knowledge of Bayesian analysis; to do performance analysis one must learn the methodologies of conducting performance analysis and processing simulation data. Investigate security issues of mobile ad hoc network and current dynamic feedback mechanisms or protocols that are used to solve or mitigate the issues. Investigate and learn how to use the network simulation tool. There are several popular network simulation tools available and we need to choose the one that best suits our needs. The selected network simulator should be studied so that we can use it as platform to implement protocol and conduct simulations. Analyze and implement the DSR protocol based on Dynamic Source Routing protocol (DSR); evaluate the network performance. Structure of the Report Since we have almost gone through the chapter one, we only briefly present the content of the subsequent chapters in this section. Preliminary Information State of the Art Analysis Design Implementation and Tests Performance Analysis Conclusion and Future Work Preliminary information we have introduced the MANET. This chapter presents other preliminary information and concepts that will be used in other parts of the thesis. Firstly four general modes of routing operations are introduced and compared. The DSR protocol, which is used as underlying routing protocol in the thesis, is explained in detail. Secondly Bayesian estimation and Beta function are explained to pave the way for the analysis of the reputation model of DSR in the chapter 4. Thirdly some techniques regarding simulation and performance analysis are presented. Finally, several popular network simulation tools are discussed and compared. Mobile Ad Hoc Network Routing Protocols Nowadays there are various routing protocols proposed for the MANET. The most popular ones are DSDV (Destination-Sequenced Distance Vector), TORA (Temporally- Ordered Routing Algorithm), DSR (Dynamic Source Routing) and AODV (Ad-hoc On Demand Distance Vector). These routing protocols can be categorized in different routing operation modes. Mode of Routing Operations These two modes concern whether or not nodes in an ad hoc network should keep track of routes to all possible destinations, or instead keep track of only those destinations of immediate interest Proactive protocols store route information even before it is needed. This kind of protocols has advantage that communications with arbitrary destination experience minimal delay. However it also suffers from the disadvantage that additional control traffic is needed to continually update stale route information. This could significantly increase routing overhead especially for the MANET where the links are often broken. Reactive protocols, on the contrary, acquire routing information only when it is actually needed. However, the latency of the communication increases tremendously especially when a node communicates to another at the first time. Source routing vs. Hop-by-hop routing These two modes concern whether the source node decides the route for a packet to be forwarded to the destination or the intermediate nodes are allowed to decide the next hop until the packet arrives at the destination. In the source routing protocols, the source node decides the route and puts the route information in the packet header. All the intermediate nodes forward the packet along the route faithfully. This kind of protocols has advantage that the intermediate nodes are not required to maintain the routing information. But it suffers from the disadvantage that the packet size grows because of source routing information carried in each packet. In the hop-by-hop routing protocols, it is sufficient for the source to know only how to get to the next hop and intermediate nodes find their own next-hops until the destination. In contrast to source routing protocols, hop-by-hop routing protocols do not increase packet size but they requires all the intermediate nodes to maintain rout ing information. Table 2-1 Categories of routing protocols has compared the performance of these four routing protocols . The results show that DSR has best throughput performance (above 95%) at all mobility rates and movement speeds. Thus we will use DSR as basic routing protocol in this thesis. The Dynamic Source Routing Protocol (DSR) John et al. proposed the dynamic source routing protocol (DSR) [1] which is a routing protocol for use in multi-hop wireless ad hoc networks of mobile nodes. DSR is an ondemand protocol, in which route are only discovered when data need to be transmitted to a node where no route has yet been discovered. The advantage of this on-demand routing protocol is that there are not any periodic routing advertisement and reducing the routing overhead. DSR is also a source routing protocol, allowing multiple routes to any destination and allows each sender to select and control the routes used in routing the packets. DSR is composed of the two main mechanisms: Route Discovery and Route Maintenance which are explained below. Route Discovery Route Discovery aims at finding routes from a source node to destination. Figure 2-1 illustrates the procedure of Route Discovery. When a source node S wants to send a data packet to some destination node D, it first searches its route cache to find whether there is a route to D. If there is no route to D, then S will initiate a Route Discovery and send out Route Request message which is propagated to all the nodes within its transmission range. At the mean time, it saves the data packet in its send buffer. The Route Request message contains the addresses of source node and destination node, a unique route request identifier and a route record which records all the intermediate nodes that this route request packet has traveled through. S appends itself to the beginning of the route record when it initiates the message. When a node receives the Route Request message, it compares the destination address in the message with its own address to judge whether itself is the destination node. If it is not, it will append its own address in the route record and propagate the message to other nodes. If the node is the destination node, it will send a Route Reply message to the source node and the message contains the source route record which is accumulated when the Route Request message is forwarded along its way to the destination. When the destination sends the Route Reply, if it uses MAC protocols such as IEEE 802.11 that require a bidirectional link, it just reverse the source route record and use it as route to send Route Reply to the source node. Otherwise it should find the route by searching its route cache or sending out a Route Request which piggybacks the Route Reply for the source node. When the source node receives the Route Reply message, it puts the returned route into its route cache. From t hen on all the packets destined to the same destination will use this route until it is broken. Route Maintenance Since the ad hoc network is dynamic and the topology of the network changes frequently, the existing routes maintained by nodes in their route cache are often broken. After forwarding a packet, a node must attempt to confirm the reachability of the next-hop node. If the node does not receive any confirmation from the next hop during a certain period of time, it will retransmit the packet. If after a maximum number of retransmission it still does not receive any confirmation, it will think the link to the next hop is broken and will send a Route Error message to the source node. DSR proposes three acknowledge mechanisms to confirm that data can flow over the link from that node to the next hop: Link-layer acknowledgement which is provided by MAC layer protocol such as IEEE 802.11. Passive acknowledgement in which a node hears the next-hop node forwarding the packet and thus confirms the reachability of the link. Network-layer acknowledgement in which a node sends an explicit acknowledgement request to its next-hop node. Passive Acknowledgement Passive Acknowledgement (PACK) is important in DSR protocol because it is used to detect whether the next hop forwards the packet or drops it. We explain it in detail in this section. Passive acknowledgement is used with the assumption that: Network links operates bi- directionally. The network interface is in the promiscuous mode. When a node taps a new packet in promiscuous mode after it originates or forwards a packet, it consider it as an acknowledgement of the first packet if both of following check success. The Source Address, Destination Address, Protocol, Identification, and Fragment Offset fields in the IP header of the two packets MUST match. If either packet contains a DSR Source Route header, both packets MUST contain one, and the value in the Segments Left field in the DSR Source Route header of the new packet MUST be less than that in the first packet. If no matched packet is found during PACK timeout, the node will consider the link between the next hop and itself is broken and will send Route Error message to the source node. Additional features DSR has additional features such as replying to route requests using cached routes, caching overheard routing information, packet salvaging and flow state extension and etc. We will introduce them in section 4.1 and discuss how they will impact the performance of network, how they will interact with DSR and whether they will be enabled in our simulation. Performance Analysis Techniques This section introduces the performance analysis techniques and methodologies that will be used in the performance evaluation. Factors and Primary Factors There are many parameters that will influence the simulation results and need to be carefully chosen in the simulations. Some parameters are chosen based on experience values or the conditions of the network we want to simulate. Others need to be tuned to optimize the network performance. We distinguish the two kinds of parameters as follows: Factors are the variables that affect the simulation result and have several alternatives. Normally they are decided based on experience. Primary factors are the factors whose effects need to be quantified. This kind of factors usually needs to be adjusted through simulation. Data Measurement The key step of the network performance analysis is to interpret the simulation result and summarize the characteristic of the network. To avoid the inaccurate simulation results due to an extreme scenario, we usually run simulations on several different scenarios. The data set of these simulations are called sample. A single number must be presented to give the key characteristic of the sample and this single number is called an average of the data. There are three alternatives to summarize a sample Mean is obtained by taking the sum of all observations and dividing this sum by the number of observations in the sample. Median is obtained by sorting the observations in an increasing order and taking the observation that is in the middle of series. If the number of the observations is even, the mean of the middle two values is used as a median. Mode is obtained by plotting a histogram and specifying the midpoint of the bucket where the histogram peaks. Confidence Interval for the Mean In our performance evaluation, the main objective is to compare the simulation results of DSR and Standard DSR to see whether there is any performance improvement. However, most simulation results are random in some degree due to the particularity of the node movement scenarios and we cannot tell whether the two systems are different. One way to minimize the random effect is to repeat the simulations with different scenarios as many times as possible and get a large sample space. Unfortunately, due to the time limitation we cannot conduct many simulations. points out that using confidence interval we can tell whether the two systems are different with smaller sample space. The confidence interval for the mean can be calculated using If the confidence intervals of the simulation results of the two systems have no overlap, then we can claim the two systems are different and one system is superior or inferior to the other. GloMoSims source and binary code can be downloaded only by academic institutions for research purposes. Commercial users must use QualNet, the commercial version of GloMoSim. OPNET Modeler OPNET Modeler is commercial network simulation environment for network modeling and simulation. It allows the users to design and study communication networks, devices, protocols, and applications with flexibility and scalability [30]. It simulates the network graphically and its graphical editors mirror the structure of actual networks and network components. The users can design the network model visually.The modeler uses object-oriented modeling approach. The nodes and protocols are modeled as classes with inheritance and specialization. The development language is C. Comparison When choosing a network simulator, we normally consider the accuracy of the simulator. Unfortunately there is no conclusion on which of the above three simulator is the most accurate one. David Cavin et al. has conducted experiments to compare the accuracy of the simulators and it finds out that the results are barely comparable [31]. Furthermore, it warns that no standalone simulations can fit all the needs of the wireless developers. It is more realistic to consider a hybrid approach in which only the lowest layers (MAC and physical layers) and the mobility model are simulated and all the upper layers (from transport to application layers) are executed on a dedicated hosts (e.g. cluster of machines). Although there is no definite conclusion about the accuracy of the three network simulators, we have to choose one of them as our simulation environment. We compare the simulators using some metrics and the results are summarized After comparing the three simulators, we decide to choose ns2 as network simulator in our thesis because Ns2 is open source free software. It can be easily downloaded and installed. The author of the thesis has used ns2 in another network related course and gotten familiar with the simulation. Ns2 uses TCL and C++ as development languages for which the author has some programming experience. The author of the DSR protocol has conducted simulation on GloMoSim and gotten performance results. We want to do the simulation on a different simulation to form comparison. State of the Art In this chapter we will introduce the start of the art security solutions in MANET with emphasis on dynamic feedback mechanisms. Firstly, we will present the general security issues/requirements of MANET to pave the way for the future investigation. Then we will discuss the state of the art security mechanisms for MANET such as payment system,trust management system, reputation system, etc. Finally, we will summarize all the security solutions we discussed in this chapter. Security Issues in Mobile Ad Hoc Network Due to lack of central infrastructural and wireless links susceptible to attacks, security in ad hoc network has inherent weakness. In section 1.2 we have discussed the reasons why mobile ad hoc network imposes security challenges that cannot be solved by traditional security mechanisms. In this section, we present the general security properties required by ad hoc network. Following are general security properties regarding ad hoc network Confidentiality: The confdiantiality property is to protect certain information from unauthorized disclosure. The information includes not only the application data that send over the routing protocol, but also the routing information itself as well as network topology and geographical location. Integrity: The integrity ensures that the transmitted message and other system asset are modified only by authorized parties. In the routing level, it requires all nodes in the network following correct routing procedure. The main challenge of ensuring integrity is that without central infrastructure and powerful computing capabilities, it is difficult to apply existing cryptography and key management systems. Availability: The availability property requires that the services or devices are exempt from denial of service, which is normally done by interruption, network or server overload. Typical examples or denial of service attack are radio jamming, in which a misbehaved node transmit radio to interference other nodes communications, and battery exhaustion, in which a misbehaved node interact with a node for no other purpose than to consume its battery energy. Authentication: The authentication property requires that the communication entitys identification is recognized and proved before communication starts. Access control: This property requires restricting resources, services or data to special identities according to their access rights or group membership. Non-repudiation: This property ensures that when data are sent from sender to receiver, the sender cannot deny that he has sent the data and the receiver cannot deny that he has received the data. Mobile nodes may conduct different misbehavior for different purposes. Po-Wah Yau classifies the misbehaved nodes into following categories. Failed nodes are simply those unable to perform an operation; this could be because power failure and environmental events. Badly failed nodes exhibit features of failed nodes but they can also send false routing messages which are a threat to the integrity of the network. Selfish nodes are typified by their unwillingness to cooperate as the protocol requires whenever there is a personal cost involved. Packet dropping is the main attack by selfish nodes. Malicious nodes aim to deliberately disrupt the correct operation of the routing protocol, denying network service if possible. These four types of misbehaved nodes actually can be categorized in two aspects: whether their misbehaviors are intentional or unintentional, and the severity of the results. Payment Systems Payment systems provide economic incentives for the cooperation in MANET. They consider that each node in MANET is its own authority and tries to maximize the benefits it gets from the network. Thus each node tends to be selfish, dropping packets not destined to them but make use of other nodes to forward their own packets. The purpose of payment systems is to encourage the cooperation within the MANET by economic incentives. There are several variations of payment systems proposed. Nuglets Nuglets is a virtual currency mechanism for charging (rewarding) server usage (provision). Nodes that use a service must pay for it (in nuglets) to nodes that provide the service. A typical service is packet forwarding which is provided by intermediate nodes to the source and the destination of the packet. Therefore either the source or the destination should pay for it. There are two models for charging for the packet forwarding service: the Packet Purse Model (PPM) and the Packet Trade Model (PTM). In the Packet Purse Model, the sender pays for the packet. It loads the packet with a number of nuglets when sending the packet. Each intermediate forwarding node acquires some nuglets from the packet that covers its forwarding costs. If a packet does not have enough nuglets to be forwarded, then it is discarded. If there are nuglets left in the packet once it reaches destination, the nuglets are lost. In the Packet Trade Model, the destination pays for the packet. Each intermediate node buys the packet from previous one for some nuglets and sells it to the next one for more nuglets until the destination buys it. Either of the two models has advantages and disadvantages. While the Packet Purse Model deters nodes from sending useless data and avoids the network overloading, the Packet Trade Model can lead to an overload of the network and the destination receives packets it does not want. On the other hand, in the Packet Purse Model it is difficult to estimate the number of nuglets th at are required to reach a given destination. But thePacket Purse Model does not need to consider this problem. To take advantages of the two models and avoid the disadvantages, a hybrid model is suggested. In this model, the sender loads the packet with some nuglets before sending it.The packet is handled according to the Packet Purse Model until it runs out of nuglets. Then it is handled according to the Packet Trade Model until the destination buys it. Counter To address the problems encountered by the nuglets approach such as difficulty in estimating pre-load nuglets and possible network overload, another payment approach based on credit counter is suggested. In this approach, the current state of each node is described by two variables b and c, where b is the remaining battery power and cstands for the value of its nuglet counter. More precisely, b is the number of packets that the node can send using its remaining energy and c is the number of packets a node canoriginate. A node can originate a number of packets N only when the condition c=N holds. When a node forwards a packet, nuglet counter c is increased by one and b is reduced by one. Thus in order to originate packets, each node must earn credits by forwarding packets. The counter solution requires tamper resistant hardware security module. Spirit S. Zhong et al. proposed Sprite [19], a credit-based system for MANET. As opposed to Nuglets or Counter they do not require tamper-proof hardware to prevent the fabrication of payment units. Instead, they introduce a central Credit Clearance Service (CCS). The basic scheme of the system is as follows. When a node receives a message the node keeps a receipt of the message and reports to the CCS when the node has a fast connection to Credit Clearance Service (CCS). The CCS then determines the charge and credits to each node involved in the transmission of a message, depending on the reported receipts of a message. In this scheme, the sender charges money. A node that has forwarded a message is compensated, but the credit that a node receives depends on whether or not its forwarding action is successful. Forwarding is considered successful if and only if the next node on the path reports a valid receipt to the CCS. Discussion on the Payment Systems The payment systems we describe in above sections either assumes a tamper resistant hardware module is available to ensure that the behavior of the node is not modified or requires a central authority server to determine the charge and credit to each node involved in the transmission of a message. Tamper resistant hardware may not be appropriate for most mobile devices because it demands advanced hardware solution and increases the cost of the devices. Lacking of central authority server is right the inherent property of MANET that causes security challenges so it is also not appropriate. Furthermore, all the approaches described above suffer from locality problems [20] that nodes in different locations of the network will have different chances for earning virtualcurrency, which may not be fair for all nodes. Usually nodes at the periphery of the network will have less chance to be rewarded. Reputation System Reputation systems have emerged as a way to reduce the risk entailed in interactions among total strangers in electronic marketplace. Centralized reputation systems have been adopted by many on-line electronic auctions such as eBay to collect and store reputation ratings from feedback providers in a centralized reputation database. Decentralized reputation systems used by MANET, on the other hand, do not use centralized reputation database. Instead, in these reputation systems, each node keeps the ratings about other node and updating the ratings by direct observation of the behaviorsof neighboring nodes or second hand information from other trusted nodes. Identifies three goals for reputation systems: To provide information to distinguish between a trust-worthy principal and an untrustworthy principals. To encourage principals to act in a trustworthy manner To discourage untrustworthy principals from participating in the service the reputation mechanism is present to protect. Most of the reputation systems in MANET are based on trust management system. Trust is such a subjective and dynamic concept that different entities can hold different opinions on it even while facing the same situation. Trust management system can work without reputation system. For example, a mobile node can form opinion about other nodes by direct experience with the nodes.We can unify reputation system and trust management system to dynamic feedback mechanisms. Former one is a global reputation system and mobile nodes share their own experiences of interaction with other nodes. The later one is a local reputation system in which mobile nodes rating the trustability of other nodes based on its own observation. DSR DSR is a reputation system aiming at coping with misbehavior in MANET. The idea is to detect the misbehaved nodes and isolate them fromcommunication by not using them for routing and forwarding and by not allowing the misbehaved nodes to use itself to forward packets. DSR stands for Cooperation Of Nodes: Fairness In Dynamic Ad-hoc Network. It usually works as an extension to on demand routing Mobile Ad Hoc Networks (MANETs) Mobile Ad Hoc Networks (MANETs) Introduction What is Mobile Ad Hoc Network? With rapid development of wireless technology, the Mobile Ad Hoc Network (MANET) has emerged as a new type of wireless network. MANET is a collection of wireless mobile nodes (e.g. laptops) that dynamically function as a network without the use of any existing infrastructure and centralized administration. It is an autonomous system where each node operates not only as an end system but also as a router to forward packets for other nodes. Since the nodes in MANET move around, the wireless links break and re-establish frequently. Furthermore, most of mobile nodes are resource limited in computing capability and battery power and therefore traditional computing content routing protocols are not suitable for MANET. Several ad hoc routing protocols have been proposed for each node acting as router and maintaining routing information. There are many other applications of MANET. For examples, MANET can be used to provide emergency Services when the network is impaired due to the damaging of existing infrastructure [8]. Computer scientists have predicted a world of ubiquitous computing in which computers will be all around us, constantly performing mundane tasks to make our lives a little easier. These ubiquitous computers connect in mobile ad hoc mode and change the environment or react to the change of the environment where they are suited. MANET is also found useful in the so-called sensor dust network to coordinate the activities and reports of a large collection of tiny sensor devices which could offer detailed information about terrain or environmental dangerous conditions. Problem Statement and Motivation Most current ad hoc routing protocols assume that the wireless network is benign and every node in the network strictly follows the routing behavior and is willing to forward packets for other nodes. Most of these protocols cope well with the dynamically changing topology. However, they do not address the problems when misbehavior nodes present in the network.A commonly observed misbehavior is packet dropping. In a practical MANET, most devices have very limited computing and battery power while packet forwarding consumes a lot of such resources. Thus some of the mobile devices would not like to forward the packets for the benefit of others and they drop packets not destined to them. On the other hand, they still make use of other nodes to forward packets that they originate. These misbehaved nodes are very difficult to identify because we cannot tell that whether the packets are dropped intentionally by the misbehaved nodes or dropped due to the node having moved out of transmission range or other link error. Packet drop significantly decreases the network performance.Traditional security mechanisms are generally not suitable for MANET because: The network lacks central infrastructure to apply traditional security mechanism such as access control, authentication and trusted third party. Limited bandwidth, battery lifetime, and computation power prohibits the deployment of complex routing protocols or encryption algorithms. New security models or mechanisms suitable for MANET must be found. Network topologies and memberships are constantly changing. Thus new intrusion detection system and entity recognition mechanisms that are suitable for mobile ad hoc networks must be designed to avoid or mitigate the behavior to the networks. Trust management systems have been recently introduced as a security mechanism in MANET. In a trust management system, a communicating entity collects evidence regarding competence, honesty or security of other network participants with the purpose of making assessment or decisions regarding their trust relationships. Here trust Objective and Sub-tasks means the confidence of an entity on another entity based on the expectation that the other entity will perform a particular action important to the trustor, irrespective of the ability to monitor or control that other entity . For example, a trust-based routing protocol can collect the evidence of nodes misbehaving, form trust values of the nodes and select safest routes based on the trust metrics.Reputations systems are often seen as a derivation of trust management system. In the reputation system, an entity forms its trust on another entity based not only on the selfobserved evidence but also on the second hand information from third parties. One of the influential reputation systems is the DSR protocol. In the trust management system, reputation system and other trust-based systems, route selection is based on the sending nodes prior experience with other nodes in the network. Its opinions about how other entities are honest are constantly changing. Thus, we call the trust manag ement systems and their derivations as dynamic feedback mechanisms. The dynamic feedback mechanisms are usually applied on the current ad hoc routing protocols to rate the trust about other nodes in the network and make routing decisions based on the trust matrix, which is formed according to the evidence collected from previous interactions. By incorporating the dynamic feedback mechanism in the routing protocol, misbehaved nodes are identified and avoided to forward packets. In this way,misbehavior can be mitigated. Objective and Sub-tasks The primary objective of this thesis is to Investigate the state of the art of dynamic feedback mechanisms and protocols analyze, implement and evaluate DSR protocols to see how it improves the network performance and what are the side effects of introducing the mechanism to the mobile ad hoc network. Following tasks must be done to achieve the primary objective. Study the preliminary knowledge that is required to carry out the main tasks. For example, to understand DSR protocol one must have some knowledge of Bayesian analysis; to do performance analysis one must learn the methodologies of conducting performance analysis and processing simulation data. Investigate security issues of mobile ad hoc network and current dynamic feedback mechanisms or protocols that are used to solve or mitigate the issues. Investigate and learn how to use the network simulation tool. There are several popular network simulation tools available and we need to choose the one that best suits our needs. The selected network simulator should be studied so that we can use it as platform to implement protocol and conduct simulations. Analyze and implement the DSR protocol based on Dynamic Source Routing protocol (DSR); evaluate the network performance. Structure of the Report Since we have almost gone through the chapter one, we only briefly present the content of the subsequent chapters in this section. Preliminary Information State of the Art Analysis Design Implementation and Tests Performance Analysis Conclusion and Future Work Preliminary information we have introduced the MANET. This chapter presents other preliminary information and concepts that will be used in other parts of the thesis. Firstly four general modes of routing operations are introduced and compared. The DSR protocol, which is used as underlying routing protocol in the thesis, is explained in detail. Secondly Bayesian estimation and Beta function are explained to pave the way for the analysis of the reputation model of DSR in the chapter 4. Thirdly some techniques regarding simulation and performance analysis are presented. Finally, several popular network simulation tools are discussed and compared. Mobile Ad Hoc Network Routing Protocols Nowadays there are various routing protocols proposed for the MANET. The most popular ones are DSDV (Destination-Sequenced Distance Vector), TORA (Temporally- Ordered Routing Algorithm), DSR (Dynamic Source Routing) and AODV (Ad-hoc On Demand Distance Vector). These routing protocols can be categorized in different routing operation modes. Mode of Routing Operations These two modes concern whether or not nodes in an ad hoc network should keep track of routes to all possible destinations, or instead keep track of only those destinations of immediate interest Proactive protocols store route information even before it is needed. This kind of protocols has advantage that communications with arbitrary destination experience minimal delay. However it also suffers from the disadvantage that additional control traffic is needed to continually update stale route information. This could significantly increase routing overhead especially for the MANET where the links are often broken. Reactive protocols, on the contrary, acquire routing information only when it is actually needed. However, the latency of the communication increases tremendously especially when a node communicates to another at the first time. Source routing vs. Hop-by-hop routing These two modes concern whether the source node decides the route for a packet to be forwarded to the destination or the intermediate nodes are allowed to decide the next hop until the packet arrives at the destination. In the source routing protocols, the source node decides the route and puts the route information in the packet header. All the intermediate nodes forward the packet along the route faithfully. This kind of protocols has advantage that the intermediate nodes are not required to maintain the routing information. But it suffers from the disadvantage that the packet size grows because of source routing information carried in each packet. In the hop-by-hop routing protocols, it is sufficient for the source to know only how to get to the next hop and intermediate nodes find their own next-hops until the destination. In contrast to source routing protocols, hop-by-hop routing protocols do not increase packet size but they requires all the intermediate nodes to maintain rout ing information. Table 2-1 Categories of routing protocols has compared the performance of these four routing protocols . The results show that DSR has best throughput performance (above 95%) at all mobility rates and movement speeds. Thus we will use DSR as basic routing protocol in this thesis. The Dynamic Source Routing Protocol (DSR) John et al. proposed the dynamic source routing protocol (DSR) [1] which is a routing protocol for use in multi-hop wireless ad hoc networks of mobile nodes. DSR is an ondemand protocol, in which route are only discovered when data need to be transmitted to a node where no route has yet been discovered. The advantage of this on-demand routing protocol is that there are not any periodic routing advertisement and reducing the routing overhead. DSR is also a source routing protocol, allowing multiple routes to any destination and allows each sender to select and control the routes used in routing the packets. DSR is composed of the two main mechanisms: Route Discovery and Route Maintenance which are explained below. Route Discovery Route Discovery aims at finding routes from a source node to destination. Figure 2-1 illustrates the procedure of Route Discovery. When a source node S wants to send a data packet to some destination node D, it first searches its route cache to find whether there is a route to D. If there is no route to D, then S will initiate a Route Discovery and send out Route Request message which is propagated to all the nodes within its transmission range. At the mean time, it saves the data packet in its send buffer. The Route Request message contains the addresses of source node and destination node, a unique route request identifier and a route record which records all the intermediate nodes that this route request packet has traveled through. S appends itself to the beginning of the route record when it initiates the message. When a node receives the Route Request message, it compares the destination address in the message with its own address to judge whether itself is the destination node. If it is not, it will append its own address in the route record and propagate the message to other nodes. If the node is the destination node, it will send a Route Reply message to the source node and the message contains the source route record which is accumulated when the Route Request message is forwarded along its way to the destination. When the destination sends the Route Reply, if it uses MAC protocols such as IEEE 802.11 that require a bidirectional link, it just reverse the source route record and use it as route to send Route Reply to the source node. Otherwise it should find the route by searching its route cache or sending out a Route Request which piggybacks the Route Reply for the source node. When the source node receives the Route Reply message, it puts the returned route into its route cache. From t hen on all the packets destined to the same destination will use this route until it is broken. Route Maintenance Since the ad hoc network is dynamic and the topology of the network changes frequently, the existing routes maintained by nodes in their route cache are often broken. After forwarding a packet, a node must attempt to confirm the reachability of the next-hop node. If the node does not receive any confirmation from the next hop during a certain period of time, it will retransmit the packet. If after a maximum number of retransmission it still does not receive any confirmation, it will think the link to the next hop is broken and will send a Route Error message to the source node. DSR proposes three acknowledge mechanisms to confirm that data can flow over the link from that node to the next hop: Link-layer acknowledgement which is provided by MAC layer protocol such as IEEE 802.11. Passive acknowledgement in which a node hears the next-hop node forwarding the packet and thus confirms the reachability of the link. Network-layer acknowledgement in which a node sends an explicit acknowledgement request to its next-hop node. Passive Acknowledgement Passive Acknowledgement (PACK) is important in DSR protocol because it is used to detect whether the next hop forwards the packet or drops it. We explain it in detail in this section. Passive acknowledgement is used with the assumption that: Network links operates bi- directionally. The network interface is in the promiscuous mode. When a node taps a new packet in promiscuous mode after it originates or forwards a packet, it consider it as an acknowledgement of the first packet if both of following check success. The Source Address, Destination Address, Protocol, Identification, and Fragment Offset fields in the IP header of the two packets MUST match. If either packet contains a DSR Source Route header, both packets MUST contain one, and the value in the Segments Left field in the DSR Source Route header of the new packet MUST be less than that in the first packet. If no matched packet is found during PACK timeout, the node will consider the link between the next hop and itself is broken and will send Route Error message to the source node. Additional features DSR has additional features such as replying to route requests using cached routes, caching overheard routing information, packet salvaging and flow state extension and etc. We will introduce them in section 4.1 and discuss how they will impact the performance of network, how they will interact with DSR and whether they will be enabled in our simulation. Performance Analysis Techniques This section introduces the performance analysis techniques and methodologies that will be used in the performance evaluation. Factors and Primary Factors There are many parameters that will influence the simulation results and need to be carefully chosen in the simulations. Some parameters are chosen based on experience values or the conditions of the network we want to simulate. Others need to be tuned to optimize the network performance. We distinguish the two kinds of parameters as follows: Factors are the variables that affect the simulation result and have several alternatives. Normally they are decided based on experience. Primary factors are the factors whose effects need to be quantified. This kind of factors usually needs to be adjusted through simulation. Data Measurement The key step of the network performance analysis is to interpret the simulation result and summarize the characteristic of the network. To avoid the inaccurate simulation results due to an extreme scenario, we usually run simulations on several different scenarios. The data set of these simulations are called sample. A single number must be presented to give the key characteristic of the sample and this single number is called an average of the data. There are three alternatives to summarize a sample Mean is obtained by taking the sum of all observations and dividing this sum by the number of observations in the sample. Median is obtained by sorting the observations in an increasing order and taking the observation that is in the middle of series. If the number of the observations is even, the mean of the middle two values is used as a median. Mode is obtained by plotting a histogram and specifying the midpoint of the bucket where the histogram peaks. Confidence Interval for the Mean In our performance evaluation, the main objective is to compare the simulation results of DSR and Standard DSR to see whether there is any performance improvement. However, most simulation results are random in some degree due to the particularity of the node movement scenarios and we cannot tell whether the two systems are different. One way to minimize the random effect is to repeat the simulations with different scenarios as many times as possible and get a large sample space. Unfortunately, due to the time limitation we cannot conduct many simulations. points out that using confidence interval we can tell whether the two systems are different with smaller sample space. The confidence interval for the mean can be calculated using If the confidence intervals of the simulation results of the two systems have no overlap, then we can claim the two systems are different and one system is superior or inferior to the other. GloMoSims source and binary code can be downloaded only by academic institutions for research purposes. Commercial users must use QualNet, the commercial version of GloMoSim. OPNET Modeler OPNET Modeler is commercial network simulation environment for network modeling and simulation. It allows the users to design and study communication networks, devices, protocols, and applications with flexibility and scalability [30]. It simulates the network graphically and its graphical editors mirror the structure of actual networks and network components. The users can design the network model visually.The modeler uses object-oriented modeling approach. The nodes and protocols are modeled as classes with inheritance and specialization. The development language is C. Comparison When choosing a network simulator, we normally consider the accuracy of the simulator. Unfortunately there is no conclusion on which of the above three simulator is the most accurate one. David Cavin et al. has conducted experiments to compare the accuracy of the simulators and it finds out that the results are barely comparable [31]. Furthermore, it warns that no standalone simulations can fit all the needs of the wireless developers. It is more realistic to consider a hybrid approach in which only the lowest layers (MAC and physical layers) and the mobility model are simulated and all the upper layers (from transport to application layers) are executed on a dedicated hosts (e.g. cluster of machines). Although there is no definite conclusion about the accuracy of the three network simulators, we have to choose one of them as our simulation environment. We compare the simulators using some metrics and the results are summarized After comparing the three simulators, we decide to choose ns2 as network simulator in our thesis because Ns2 is open source free software. It can be easily downloaded and installed. The author of the thesis has used ns2 in another network related course and gotten familiar with the simulation. Ns2 uses TCL and C++ as development languages for which the author has some programming experience. The author of the DSR protocol has conducted simulation on GloMoSim and gotten performance results. We want to do the simulation on a different simulation to form comparison. State of the Art In this chapter we will introduce the start of the art security solutions in MANET with emphasis on dynamic feedback mechanisms. Firstly, we will present the general security issues/requirements of MANET to pave the way for the future investigation. Then we will discuss the state of the art security mechanisms for MANET such as payment system,trust management system, reputation system, etc. Finally, we will summarize all the security solutions we discussed in this chapter. Security Issues in Mobile Ad Hoc Network Due to lack of central infrastructural and wireless links susceptible to attacks, security in ad hoc network has inherent weakness. In section 1.2 we have discussed the reasons why mobile ad hoc network imposes security challenges that cannot be solved by traditional security mechanisms. In this section, we present the general security properties required by ad hoc network. Following are general security properties regarding ad hoc network Confidentiality: The confdiantiality property is to protect certain information from unauthorized disclosure. The information includes not only the application data that send over the routing protocol, but also the routing information itself as well as network topology and geographical location. Integrity: The integrity ensures that the transmitted message and other system asset are modified only by authorized parties. In the routing level, it requires all nodes in the network following correct routing procedure. The main challenge of ensuring integrity is that without central infrastructure and powerful computing capabilities, it is difficult to apply existing cryptography and key management systems. Availability: The availability property requires that the services or devices are exempt from denial of service, which is normally done by interruption, network or server overload. Typical examples or denial of service attack are radio jamming, in which a misbehaved node transmit radio to interference other nodes communications, and battery exhaustion, in which a misbehaved node interact with a node for no other purpose than to consume its battery energy. Authentication: The authentication property requires that the communication entitys identification is recognized and proved before communication starts. Access control: This property requires restricting resources, services or data to special identities according to their access rights or group membership. Non-repudiation: This property ensures that when data are sent from sender to receiver, the sender cannot deny that he has sent the data and the receiver cannot deny that he has received the data. Mobile nodes may conduct different misbehavior for different purposes. Po-Wah Yau classifies the misbehaved nodes into following categories. Failed nodes are simply those unable to perform an operation; this could be because power failure and environmental events. Badly failed nodes exhibit features of failed nodes but they can also send false routing messages which are a threat to the integrity of the network. Selfish nodes are typified by their unwillingness to cooperate as the protocol requires whenever there is a personal cost involved. Packet dropping is the main attack by selfish nodes. Malicious nodes aim to deliberately disrupt the correct operation of the routing protocol, denying network service if possible. These four types of misbehaved nodes actually can be categorized in two aspects: whether their misbehaviors are intentional or unintentional, and the severity of the results. Payment Systems Payment systems provide economic incentives for the cooperation in MANET. They consider that each node in MANET is its own authority and tries to maximize the benefits it gets from the network. Thus each node tends to be selfish, dropping packets not destined to them but make use of other nodes to forward their own packets. The purpose of payment systems is to encourage the cooperation within the MANET by economic incentives. There are several variations of payment systems proposed. Nuglets Nuglets is a virtual currency mechanism for charging (rewarding) server usage (provision). Nodes that use a service must pay for it (in nuglets) to nodes that provide the service. A typical service is packet forwarding which is provided by intermediate nodes to the source and the destination of the packet. Therefore either the source or the destination should pay for it. There are two models for charging for the packet forwarding service: the Packet Purse Model (PPM) and the Packet Trade Model (PTM). In the Packet Purse Model, the sender pays for the packet. It loads the packet with a number of nuglets when sending the packet. Each intermediate forwarding node acquires some nuglets from the packet that covers its forwarding costs. If a packet does not have enough nuglets to be forwarded, then it is discarded. If there are nuglets left in the packet once it reaches destination, the nuglets are lost. In the Packet Trade Model, the destination pays for the packet. Each intermediate node buys the packet from previous one for some nuglets and sells it to the next one for more nuglets until the destination buys it. Either of the two models has advantages and disadvantages. While the Packet Purse Model deters nodes from sending useless data and avoids the network overloading, the Packet Trade Model can lead to an overload of the network and the destination receives packets it does not want. On the other hand, in the Packet Purse Model it is difficult to estimate the number of nuglets th at are required to reach a given destination. But thePacket Purse Model does not need to consider this problem. To take advantages of the two models and avoid the disadvantages, a hybrid model is suggested. In this model, the sender loads the packet with some nuglets before sending it.The packet is handled according to the Packet Purse Model until it runs out of nuglets. Then it is handled according to the Packet Trade Model until the destination buys it. Counter To address the problems encountered by the nuglets approach such as difficulty in estimating pre-load nuglets and possible network overload, another payment approach based on credit counter is suggested. In this approach, the current state of each node is described by two variables b and c, where b is the remaining battery power and cstands for the value of its nuglet counter. More precisely, b is the number of packets that the node can send using its remaining energy and c is the number of packets a node canoriginate. A node can originate a number of packets N only when the condition c=N holds. When a node forwards a packet, nuglet counter c is increased by one and b is reduced by one. Thus in order to originate packets, each node must earn credits by forwarding packets. The counter solution requires tamper resistant hardware security module. Spirit S. Zhong et al. proposed Sprite [19], a credit-based system for MANET. As opposed to Nuglets or Counter they do not require tamper-proof hardware to prevent the fabrication of payment units. Instead, they introduce a central Credit Clearance Service (CCS). The basic scheme of the system is as follows. When a node receives a message the node keeps a receipt of the message and reports to the CCS when the node has a fast connection to Credit Clearance Service (CCS). The CCS then determines the charge and credits to each node involved in the transmission of a message, depending on the reported receipts of a message. In this scheme, the sender charges money. A node that has forwarded a message is compensated, but the credit that a node receives depends on whether or not its forwarding action is successful. Forwarding is considered successful if and only if the next node on the path reports a valid receipt to the CCS. Discussion on the Payment Systems The payment systems we describe in above sections either assumes a tamper resistant hardware module is available to ensure that the behavior of the node is not modified or requires a central authority server to determine the charge and credit to each node involved in the transmission of a message. Tamper resistant hardware may not be appropriate for most mobile devices because it demands advanced hardware solution and increases the cost of the devices. Lacking of central authority server is right the inherent property of MANET that causes security challenges so it is also not appropriate. Furthermore, all the approaches described above suffer from locality problems [20] that nodes in different locations of the network will have different chances for earning virtualcurrency, which may not be fair for all nodes. Usually nodes at the periphery of the network will have less chance to be rewarded. Reputation System Reputation systems have emerged as a way to reduce the risk entailed in interactions among total strangers in electronic marketplace. Centralized reputation systems have been adopted by many on-line electronic auctions such as eBay to collect and store reputation ratings from feedback providers in a centralized reputation database. Decentralized reputation systems used by MANET, on the other hand, do not use centralized reputation database. Instead, in these reputation systems, each node keeps the ratings about other node and updating the ratings by direct observation of the behaviorsof neighboring nodes or second hand information from other trusted nodes. Identifies three goals for reputation systems: To provide information to distinguish between a trust-worthy principal and an untrustworthy principals. To encourage principals to act in a trustworthy manner To discourage untrustworthy principals from participating in the service the reputation mechanism is present to protect. Most of the reputation systems in MANET are based on trust management system. Trust is such a subjective and dynamic concept that different entities can hold different opinions on it even while facing the same situation. Trust management system can work without reputation system. For example, a mobile node can form opinion about other nodes by direct experience with the nodes.We can unify reputation system and trust management system to dynamic feedback mechanisms. Former one is a global reputation system and mobile nodes share their own experiences of interaction with other nodes. The later one is a local reputation system in which mobile nodes rating the trustability of other nodes based on its own observation. DSR DSR is a reputation system aiming at coping with misbehavior in MANET. The idea is to detect the misbehaved nodes and isolate them fromcommunication by not using them for routing and forwarding and by not allowing the misbehaved nodes to use itself to forward packets. DSR stands for Cooperation Of Nodes: Fairness In Dynamic Ad-hoc Network. It usually works as an extension to on demand routing

A Computer For All Students :: essays research papers

SOUNDOFF--A Computer for All Students--Revisited The introduction of the graphing calculator has changed the structure of teaching and learning mathematics. This made it possible for everybody to receive the benefits of a computer-generated visualization without the high cost of a computer. These graphing calculators over the years have lowered in cost, became easier to use, and are more portable. The next generation of graphing computers has arrived with the recent introduction of the Texas Instrument TI-92. This relative inexpensive calculator will allow more high school teachers to teach an area mostly untouched, computer symbolic algebra and computer interactive geometry, because it has not been practical or possible. The TI-92 is merely the beginning of the new revolution of hand-held computing tools. The next challenge mathematics teachers are facing is the teaching of traditional paper-and-pencil symbolic algebra skills. This task has been made obsolete by the more accurate and faster computer symbolic algebra algorithms. Students can get a far better illustration of important concepts and applications of mathematics with these new hand-held tools than with the traditional paper-and-pencil task. The paper-and-pencil task and other traditional skills must still be acquired, but students should spend less time acquiring it. More emphasize must be put on computing tools. Students should take advantage of the computer technology to become powerful and thoughtful "problem solvers." The process of changing from traditional methods to a more computer-oriented environment has to be met by the education and mathematics community. Educators should have textbooks that better represents the new technology. Teachers need to be more technology literate. The mathematics community must dispel the image of "doing mathematics" with the traditional paper-and-pencil method. These reforms can better teach students important skills needed for the future. The use of technology in mathematics will give students an advantage mathematics and related technology. Students will need that advantage if they wish to compete in the twenty-first century. Opinion This article stressed very important issues educators, teachers, and the mathematics community must face. The reform will change the course of mathematics in school and elsewhere. As a student, I am very concern about the future of mathematics.

The First Amendment Essay -- essays research papers

Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people to assemble peacefully, and to petition the Government for e redress of grievances. The first and inargueably the most significant of the amendments to our Constitution is the First Amendment. The amendment that established our freedoms as citizens of our new confederation. The First Amendment insured, among other things, freedom of speech and of the press. Since the establishment of these rights, they have often been in question. People have debated over, "What is too much freedom?", and "When is this freedom not enough?" I believe that these rights were established to protect the people, and as a society, we must try to determine whether they are. One of the major organizations that exercises free speech is the press. The press has coined the phrase, "It is the people's First Amendment right to know." This first example best relates to a situation we have now; that of national crisis. The press has the right to release information to the public, but they must use judgment in what they release. Certain news that they might release could put people in danger, therefore taking away the right of all people to be safe. For many years, the idea of the press telling too much has been made fun of. In popu...

Issues in Multicultural Education Essay

Research has shown that teachers of diverse backgrounds can have a positive effect on the success of students of color. In Washington, the number of teachers of color is just seven percent compared to the twenty-four percent of students. In Seattle, over fifty percent of students are of color and only ten percent of Seattle teachers represent the diversity in their classroom. (Martinez-Foundation, 2011). Our children deserve to feel comfortable, motivated, respected, and understood in their schools and especially in their classrooms. If a teacher does not have the tools, resources, or education on how to use differentiated instruction in her class, and how to best understand the different cultures, some kids may fall behind in their ability to achieve academically. Our future depends on the children of today and the educations that they receive. Cultural competence is: †¢ Knowing the community where the school is located. †¢ Understanding all people have a unique world view. †¢ Using curriculum that is respectful of and relevant to the cultures represented in its student body. †¢ Being alert to the ways that culture affects who we are. †¢ Placing the locus of responsibility on the professional and the institution. †¢ Examining systems, structures, policies and practices for their impact on all students and families. †Cultural competence will allow teachers to successfully teach students who come from different cultural backgrounds.† (OSPI, 2011) There is now a way to enable the success of cultural competence among teachers in our city. Over 100 different languages are spoken in Seattle Public Schools, and 24 percent of the district’s 46,000 students are bilingual speakers. To meet the increasing need for bilingual teachers in both general and special education classes, Seattle Public Schools has partnered with the state’s Professional Educator Standards Board, the Seattle Education Association and City University to provide a dual certification program for the district’s paraprofessionals. Cultural competence provides a set of skills that professionals need in order to improve practice to serve all students and communicate effectively with their families. (OSPI, 2011). Cultural competence training would give teachers the opportunity to confront their stereotypes and biases that they hold that directly affect the way teachers see, and teach their students. Biases and stereotypes within a teacher’s classroom can negatively affect the achievements of his/her students. One of the ways this program will be funded is through the SEA membership. The SEA membership believes in closing the academic achievement gap and that having classroom teachers that reflect our student population will help in accomplishing that goal,† comments Wendy Kimball, President of SEA. â€Å"Support for paraprofessionals and secretaries/office personnel is critical given the difficulty of going back to school to earn a teaching certificate and working full time.† Kimball continues, â€Å"SEA is committed to supporting staff with the resources of time and money so they can earn a certificate. The funding for this program came from reallocating money during the 2004-2009 contract bargaining from the sabbatical funds and a settlement agreement.† ( Kimball, 2011).

The man we call Benjamin Franklin

The aim of this paper is to compare and contrast the websites on Ben Franklin’s biography and his autobiography. While disseminating the life of Benjamin Franklin through his autobiography, one learns much about the man. However when disseminating information found in the three websites below, another man slowly creeps out from behind the man already revealed. Which one is the real Benjamin Franklin? While observing the cornucopia of a man one learns that only by the process of comparing and contrasting will one be able to fix a solid face on the man we call Benjamin Franklin. All the websites addressed in this paper share common subject matter yet are different in terms of analytical approach and main focus. The biography by Edmund S. Morgan calls upon the reader to reconsider traditional assumptions about Benjamin Franklin and move away from standardized cliches. While he is best known as the author of the Declaration of Independence, the Treaty of Peace with Great Britain, and the Constitution, these weren’t his main achievements; furthermore, the documents (with the exception of the Declaration of Independence) didn’t reflect his views and beliefs.However, this shouldn’t lead to the conclusion that Franklin was a not-so-important figure in the American history. Rather than that, the author suggests that Franklin should be applauded for other achievement and traits of character: ‘His was probably the most brilliant mind that most people who knew him had ever met, but he seldom showed it in public†¦[H]is mind would be quietly at work, trying to understand the world and the people he found in it, thinking of ways to make their lives easier’ (Morgan, 2005, para. 4). Edmund S.Morgan believes that one of the major contributions of Benjamin Franklin was through his writings. Also, more attention should be paid to Franklin’s role as an advocate for American interests in England. In general, the biography tries to present a softer side of Franklin’s personality: ‘It may be well at first to dispel the image of him as an overweight scholar peering from his desk over the bifocal glasses he invented’ (Morgan, 2005, para. 8). PBS website also tries to reveal Ben Franklin’s personality to the readers. The website focuses on multiple identities Franklin possessed — both as a public figure and personality.The website glorifies Franklin as Abolitionist, Almanac maker, Advertiser, Balloon enthusiast, Bifocals inventor, Composer, Cartoonist, Civic Citizen, Chess Player, Deist, Diplomat, Daylight Savings advocate, Enlightenment thinker, Electricity pioneer, Experimenter, Entrepreneur, Founding Father, Flirt, Fire fighter, Glass Armonica creator, Gulf Stream mapper, Genius, Humorist, Health nut, Inventor, International celebrity, Insurer, Junto creator, Journalist, Kite flyer, Librarian, Lightning rod inventor, Londoner, Medical Engineer, Militia member, Mathematician, M ason, Natural philosopher, Organizer (militia, fire dept., street cleaning), Odometer maker, Printer, Public relations master, Publisher, Prankster, Questioner, Quartermaster, Quintessential American, Revolutionary, Reader, Scientist, Swimmer, Self-made man, Traveler, Treaty signer, University builder, Volunteer, Visionary, Vegetarian (temporarily), Writer, Weight lifter, Xenophile, Young prodigy, Yankee, Yarn spinner, and Zealot. Perhaps the most interesting out of all these epithets is ‘Quintessential American.’ The website tries to paint a picture of Franklin as a typical representative of the American nation and a symbol of all its virtues and achievements, such as Self-education, Physical Activity, and Moral Perfection. At the same time, the website acknowledges that Benjamin Franklin was no ordinary man, since he possessed outstanding qualities and skills. It is suggested that Ben Franklin helped define the concept of ‘good citizenship’ through his in volvement in and commitment to community on the local level and the nation on the global level:‘Ben Franklin believed that people volunteering together in a spirit of cooperation could accomplish great things. Driven by a strong sense of civic duty, he involved himself in his community and his nation’ (PBS, 2002, ‘Citizen Ben,’ para. 1). The website presents Franklin’s biography in an interactive and engaging way without compromising accuracy and objectivity. The only limitation of this resource is that the information is not well-structured and far from presenting a comprehensive picture.The third website present the most, in my opinion, consistent and informative version of Franklin’s biography. It is structured according to the major periods of Franklin’s life, i. e. ‘Humble Beginnings: Franklin in Boston,’ ‘A True Journeyman: Franklin in Philadelphia,’ ‘A Promise Unfulfilled: Franklin in London,â€⠄¢ ‘Sprouting Roots: Back in Philadelphia,’ ‘A Busy Retirement,’ and ‘The American Patriot: Franklin and Independence.’ Each section of the biography presents all the necessary information without going into unnecessary detail. Another compelling feature of this biography is that it is accompanied with abundant graphical aid. Yet it would be a mistake to say that ThinkQuest presents a dry and scholarly biography of Benjamin Franklin; it offers human touch through little entertaining details about this great man:‘Inspired by his namesake uncle Benjamin, young Ben composed historical ballads (one was about the pirate Blackbeard) that were printed by his brother James in his fledgling print shop. The poems sold well’ (ThinkQuest, 1998, ‘Interesting Facts’). In order to determine how credible a certain piece of information is, it is necessary to analyze the source of this information in terms of legitimacy and possible bia s. Edmund S. Morgan is a well-established historian specializing in early colonial history of America:‘Edmund Morgan has authored dozens of books on Puritan and early colonial history, which are acclaimed for both their scholarly focus and their appeal to a general audience†¦ Morgan, who joined the Yale faculty in 1955 and retired in 1986, has received many†¦honors during his long teaching career at Yale†¦Currently the chair of the board of The Benjamin Franklin Papers—the University's massive project publishing materials related to the Founding Father and inventor—Morgan is now at work on a study of Franklin, who, he believes, is one of the most interesting people who ever lived’ (Gonzalez, 2001).However, excessive admiration with Benjamin Franklin might come as a detriment to impartiality and objectivity — the two essential characteristics of any biographical writing. PBS website has little bias of this kind, however, it is often un clear where the information they are using comes from. There are no references or acknowledgements; no links to any works of Franklin or credible historical evidence is present. While Edmund S. Morgan extensively refers to Franklin’s own works, PBS website presents a simplified and pared-down version of Franklin biography. ThinkQuest is the only website that cites its references in an appropriate way.The authors of the biography acknowledge that they based their writing on such publications as Benjamin Franklin by Carl Van Doren, The Man Who Dared the Lightning-A New Look at Benjamin Franklin by Thomas Fleming, The Autobiography of Benjamin Franklin, Ben Franklin Laughing by P. M. Zall, Benjamin Franklin: Founding Father and Inventor by Leila Merrell Foster, and a number of other books and media resources. ThinkQuest is also an interesting information resource since it provides a sound general overview of the historical conditions existing in America in Franklin’s time s.The website offers definition of different historical phenomena that are important for the general narrative, such as King George I, French and Indian War (1754-1763), and other. All the biographies present a certain picture of colonial America: through the life career of Benjamin Franklin, it is possible to understand tense relations between Europe and America, heated debate around the issue of slavery, and the rise of American identity and civil consciousness. However, the most credible source of information on Franklin’s life and times is his autobiography.This autobiography is of great relevance to the modern reader, and not merely for the reason that it provides an insight into the life of Benjamin Franklin. In his autobiography, Franklin shares his thoughts as to the organization of state and society, role of the citizens, position of America on the world’s stage and other matters of great interest and importance even for the modern reader. For example, he expr esses concerns over the clash between religion and civil notion of citizenship, as he recollects that English were trying to plant certain religious ideas in America:‘[S]ince not a single moral principle was inculcated or enforc'd, their aim seeming to be rather to make us Presbyterians than good citizens (Franklin, 2003, p. 66). ‘As for additional and types of sources, that would give greater confidence in your understanding Franklin, it is necessary to mention Franklin’s writings in the first place. As Edmund S. Morgan (2005, para. 5) correctly points out, ‘[i]n the awesome bulk of his papers, equivalent of 47 fat volumes of print, all available on this website, we can see Franklin whole.’ Additional insight can be gained from reviewing resources dedicated to the American colonial history: greater understanding of conditions and developments of that era can aid the process of enhancing knowledge about Benjamin Franklin as a statesman, scientist, and outstanding public figure. References Franklin, Benjamin. (2003). The Autobiography of Benjamin Franklin. New York: Touchstone. Gonzalez, Susan. (January 12, 2001). ‘Edmund S. Morgan: Sterling Professor Emeritus. ’ Retrieved September 5, 2007, from http://www.yale. edu/history/faculty/morgan. html Morgan, Edmund S. (2005). ‘Introduction to the Papers of Benjamin Franklin. ’ Retrieved September 5, 2007, from http://www. franklinpapers. org/franklin/framedMorgan. jsp;jsessionid=86AD99C9931B8DF535D2C1CD6A1E6923 PBS. (2002). ‘Benjamin Franklin. ’ Retrieved September 5, 2007, from http://www. pbs. org/benfranklin/ ThinkQuest. (1998). ‘The Biography of Benjamin Franklin. ’ Retrieved September 5, 2007, from http://library. thinkquest. org/22254/home. htm