Leonardo Da Vincis journey to a master of art Research Proposal

Leonardo Da Vincis journey to a master of art - Research Proposal Example He was the dishonest son of Messer Piero Fruosino di Antonio da Vinci, a Florentine legal representative and Caterina, who was a peasant. Leonardo had no last name in the contemporary way, though ‘da Vinci’ plainly meaning ‘of Vinci’ was his family name given to him, â€Å"Leonardo di ser Piero da Vinci†, which means â€Å"Leonardo, son of Piero from Vinci.† A little bit is acknowledged regarding his early days, which has been the focus of past speculation by a lot of historians. When Leonardo was five years old, he went to reside in the house of his father, along with his grandparents and uncle namely Francesco, in a little town of Vinci, where his father had wedded with a sixteen year old girl, Albiera. She loved Leonardo however unluckily she passed away in a young age3. Just two events of his early days are recorded. First one, which he observed as a portent, was when a kite crashed from the skies and floated above his cradle, its tail feat hers combing his face. The second confrontation took place while he was traveling around in the mountains. He found a cave and documented his feelings at being, on one hand, frightened that a number of huge monsters may wait there and at the same time, motivated by inquisitiveness to find out what was in the cave4. In 1466, when he was fourteen, Leonardo was trained by one of the most victorious artiste of his time named as Andrea di Cione, also identified as Verrocchio. The workshop of this famous teacher was in the mid of the scholarly currents of Florence, declaring the little Leonardo of an education in the subject of humanities. As a trainee, Leonardo would have been educated in all the innumerable talents that were engaged in a customary workshop. Though a lot of craftsmen concentrated in work for example frame-making, gilding and bronze casting. Leonardo would have been uncovered to a huge variety of technical abilities and had the chance to study drafting,

Beijing Sammies Essay Example for Free

Beijing Sammies Essay The AGROVOC Concept Server (AGROVOC/CS) Workbench is a web-based working environment consisting of numerous functionalities for the distributed management and enhancement of the AGROVOC/CS built from the AGROVOC thesaurus. Following the Semantic Web’s vision, that emphasizes collaboration in the development of data and metadata to be shared and reused across the web, the management of AGROVOC will progressively be transferred from a few individuals in FAO to a wider community of international AGROVOC experts. These interested and competent users will share the collaborative maintenance and extension of AGROVOC, one of the most frequently used terminological resources for agricultural information management in the world. Maintenance of the future extended AGROVOC will thus be completely decentralized with people worldwide contributing to its development. This report provides a brief note on the technical aspects of the AGROVOC/CS Workbench. Technical details †¢ Multilingual web interface and content (UTF8). †¢ The software is developed in pure JAVA (version 1. 5. x), with no calls to any third party modules requiring precompiled DLLs or other operating system specific features. †¢ The Google Web Toolkit (GWT) is used with an Eclipse plug-in for development of the system. It is used to build the system as a fully Java based AJAX client browser application that is compatible with all common web browsers. †¢ Where possible the JSP 2. 0 Expression Language (EL) is used for any JSP development within the project (it’s a way of writing script-less JSP pages). Protege OWL api framework is used to connect OWL. †¢ MySQL is used as RDBMS. †¢ The system is DBMS-independent. Additional database abstraction layer for interacting with the OWL backbone and the relational database will be used (e. g. the hibernat e persistence and query service, etc. ). The system follows FAO guidelines for HTML publishing: †¢ Guidelines for Web site development; †¢ File naming convention and file organization guidelines; †¢ Check list for the clearance of Web sites. In summary, the system is based on the following components: Development components †¢ Eclipse 3. 2 †¢ JAVA-JDK version jdk1. 5. x †¢ Apache Tomcat (that supports JSP and JAVA Servlets) Google Web Toolkit (for AJAX framework), version 1. 4. 60 †¢ Google Web Toolkit Incubator, version 1. 4 †¢ Protege OWL API 3. 4 libraries †¢ Hibernate 3. 0 libraries †¢ Hibernate 4 GWT, version 0. 5 RC2 †¢ MySQL version 5 Server side †¢ Windows XP, Windows 2000, or Linux †¢ Apache Tomcat 5. 5. 9 or higher †¢ JAVA-JDK version jdk1. 5. x or higher †¢ MySQL version 5 or higher †¢ Protege OWL API 3. 4 libraries †¢ Hibernate 3. 0 libraries †¢ Hibernate 4 GWT, version 0. 5 RC2 †¢ WAR file with compiled JAVA files and necessary libraries Current Server Configuration †¢ OS : Debian GNU/Linux 2. 6. 22-2 †¢ CPU: AMD 64 bit †¢ Memory: 8GB †¢ MYSQL version: 5. 0. 45 TOMCAT Version: 6. 0. 14 †¢ Java-JDK: 1. 6. 0_04 Required Application 1. MySQL version 5 or above Available link to download: http://dev. mysql. com/downloads/ 2. Apache Ant version 1. 7. 1 or above Available link to download: http://ant. apache. org/ 3. JAVA JDK version jdk. 1. 5. x or above Available link to download: http://java. sun. com/javase/downloads/index. jsp 4. Apache Tomcat version 6 or above Available link to download: http://tomcat. apache. org/download-55. cgi 5. Protege Version 3. 4 beta Build 130 Available link to download: http://protege. cim3. net/download/old-releases/3. 4%20betas/build-130/full/ 6. GWT Version 1. 4 Build 1. 4. 62 Available link to download: http://code. google. com/webtoolkit/versions. html The Step of Configuration 1. Download AGROVOC Concept Server Workbench code from the CVS Server. 2. Download the sql script from CVS Server at folder named sql. Create the database. †¢ Run the sql script file located at your_directorySQLadministrator_agrovocwb _v_0_2_beta. sql This will install administrator_agrovocwb database. †¢ Run sql script file to install the owl model database located at your_directorySQLlank model _v_0_2_beta. sql Here we have provided blank owl model. †¢ You can convert owl file directly to database by using stand alone java program located at: our_directorysrcorgfaoaoscsserverprotegeconvertToDatabaseProject. java †¢ You need the change the variables in the file. |18 private final static String url = jdbc:mysql://; | |19 private final static String table = ; | |20 private final static String user = ; | |21 private final static String password = ; | |22 private final static String uri = file:/c:/; | 3. To add model in the ontology list, go to database and table and insert new row with these values. Ontology id: (Auto increment) †¢ Ontology Name: Blank Model †¢ Ontology Description: AGROVOC Concept Server Workbench Blank AOS Module †¢ Database URL: jdbc:mysql://:3306/? requireSSL=falseuseUnicode=truecharacterEncoding=UTF-8 †¢ Database Driver: com. mysql. jdbc. Driver †¢ Table Name: †¢ Database Username: †¢ Database Password: †¢ Display Ontology on the list: 0 for hide and 1 for Show 4. Use java editor to †¢ Change the configuration of the hibernate file that located in your_directorysrchibernate. cfg. xml Change the property of your connection password instead of â€Å"your_password† and change the property of your connection url instead of â€Å"your_url†. 13 your_password | |14 jdbc:mysql://your_url | †¢ Change the configuration of the database properties that located in your_directorysrcorgfaoaoscsserverowlDatabaseC onnection. properties Change the property of your username of database instead of â€Å"your_username† and change the property of your password of database instead of â€Å"your_password†. |4 userAdminDB = your_username | |5 passwordAdminDB = your_password | †¢ Change the configuration of the mail file that located in your_directory srcorgfaoaoscsutilityMail. properties Change the property of your host name instead of â€Å"your_mailserver_host†, change the property of your port instead of â€Å"your_port†, change the property of your user instead of â€Å"your_user†, change the property of your password instead of â€Å"your_password† and change the property of your from information instead of â€Å"sender_email†. |1 host=your_mailserver_host | |2 port=your_port | |3 user=your_user | |4 password=your_password | |5 from= sender_email | †¢ Run build file to create war file using Apache ANT. 5. Copy the war file to folder of tomcat installation directory. 6. You can use the program by opening your browser and type †¢ http://localhost:8080/your_project_name

Mobile Ad Hoc Networks MANET

Mobile Ad Hoc Networks MANET Abstract Mobile Ad Hoc Network (MANET) is a wireless network capable of autonomous operation. MANET routing has no fixed base station and hence nodes in the network are mobile and self configuring. A MANET is characterized by multi hop routing so that nodes are not connected to layer 2 but can communicate through layer 3 routing. In MANET every node is a potential router and the topologies are dynamic due to node mobility. This paper presents a comprehensive study of four MANET routing protocols ADOV (Ad Hoc On demand Distance Vector), DSR (Dynamic Source Routing), OLSR (Optimized Link State Routing) and TORA (Temporally Ordered Routing Algorithm). For experimental purpose six scenarios have been considered. These 6 scenarios are generated with 3 different traffic parameters namely high resolution video, light HTTP and high FTP load. This traffic was passed individually on to each scenario on 2 different node setup (20, 100 nodes). Finally, graphical evaluation of each protocol was based on t heir performances which are calculated on the basis of performance metrics used which are End to end delay, Network load and Throughput. Chapter 1: Introduction This chapter demonstrates a brief overview of the project. Now days in our day to day life we see so many changes around the world accelerating with respect to technology. In this technical world Internet has brought revolution in communication media. Communication is said to the method of information exchange either between two people or between two end users (in terms of computers). Communication is said to be done when a file or a message is passed over the medium among two people. Here the usage of internet comes into existence. Internet can be used as shared medium for information interchange between users around the globe. This information can be of any type: Short Message Mail File transfers Video Audio etc When these types of information are passed among internet, it uses either the wired media (for connecting users locally) or wireless media (for connecting locally or globally). When this information exchange is done the packets carry that information through the protocols available for the respective media to deliver the packet to the destination. This is the process of information exchange. In this paper, similar work is experimented over MANET (Mobile Ad Hoc Networks) [chapter 2] for information exchange using four different protocols. This setup was done internally over a virtual setup of networks using OPNET modeller 14.5. So the investigation of protocols is done based on the performance of each protocol. In the scenarios, each protocol is passed with 3 different types of traffics namely: High FTP load, High Resolution Video and Light HTTP Browsing. This thesis concludes the performance of four routing protocols towards through the end. Keywords: MANET, AODV, OLSR, TORA, DSR, OPNET Modeler 14.5. 1.1 Organisation of Thesis: This thesis gives an overview of how the project is organised with respect to each chapter. The very first chapter is Introduction of the Thesis, which shows a project idea and the tasks to achieve the goals. Second chapter Literature Survey which contains the studies and work which has been done previously by other authors on the related topics with the parameters used by them for their work. The scenarios used for my work are related somewhere by overall different results are taken with different parameters used. Again the classification and the background work of MANETs are explained following the comparison of MANET routing protocols. The parameters and scenarios used for my work are explained briefly with the simulation setup in chapter 3, Implementation. The results of the simulations and experiments performed are explained in chapter 4, Performance Evaluation and Design. The results are taken graphically which helps in comparing the results for routing protocols against the pe rformance metrics used to investigate the performance. The graphs are explained briefly in chapter 4. The results gathered with the help of scenarios in chapter 3 are concluded with the future work on the routing protocols in chapter 5, Conclusion and Future Work. Finally the supported documents for the project which helped in making the simulation and project start up is kept in Appendix A. And finally chapter 6 shows all the sources and references used for the thesis to help in achieving all the supported information and work. 1.2 Objective of Work The main objective of this work is to study the different routing protocols, which are developed for Mobile Ad hoc networks (MANETs), and to compare the different routing protocols by using simulation tool OPNET Modeler 14.5. As a part of the work four major routing protocols OLSR, AODV, DSR and TORA have been selected and carried out the simulations for comparing the performance of these protocols. Three performance metrics delay; Network Load and Throughput are used to compare the performance of the routing protocols. Objective 1 To get a clear understanding and functioning of different routing protocols for Mobile Ad hoc networks. This objective could be achieved by reading and understanding the various papers available on routing protocols of Mobile Ad hoc networks. Objective 2 To do a literature survey of previous work done on MANET Routing Protocols so that something different and efficient simulation could be introduced. For this objective different articles and papers published has been studied thoroughly and analysed from websites, books and all relevant resources available. By going through literature survey on routing protocols, the desired simulation environment and setup have been introduced with different simulation parameters. Literature Survey is explained in chapter 2. Objective 3 Conducting an experiment and collecting the output data: This objective has been achieved by designing the appropriate networks with the appropriate simulation parameters and running a simulation for different protocols for different performance metrics. After conducting the simulation the output data have been collected graphically. The results are shown graphically and explained in the project in chapter 4. Objective 4 Analyzing the output data and ending up with summary and the conclusion: The results have been studied and explained in chapter 4. After studying the simulation results conclusion has been made with some future work which can be done further. Conclusion of the project and future work is explained in chapter 5. Chapter 2: Literature Survey 2.1 Introduction This chapter gives a brief introduction about the work done in previous related papers and reports related to this project. In addition, the introduction to the routing protocols and their classification with respect to routing is demonstrated. This chapter is a short review of the previous work done and the additional objectives regarding routing protocols. The four MANET routing protocols are selected to evaluate the performances; they are OLSR, AODV, DSR and TORA. The further implementations of these protocols are explained later in this thesis (Chapter 3). MANET is an infrastructure less network which provides the freedom to the nodes to be free to move anywhere in the network (Stefano Basagni, 2004). 2.2 Related Work on Routing Protocols: As we see from (Mahmoud), analysis of two reactive protocols DSR and TORA were done using OPNET Modeller. In their simulation scenario, they used 50 wireless devices in each scenario with constant traffic parameters and protocol specification settings. They have passed FTP traffic of 1000 bytes making it constant throughout the simulation. Evaluation of these protocols was done based on the performance metrics used which are: Delay, Data dropped, Throughput and media access delay. Their simulation results shows that DSR performance was better than TORA in terms of throughput as TORA produces less throughput due to additional overhead used for path creation and path maintenance. At the same time TORA minimizes communication overhead by localization which results in less delay when compared to DSR as there is no such mechanism in DSR. Similarly, from (Zukarnain, 2009) they have done evaluation of MANET routing protocol AODV in order to establish the connection between the nodes since the mobile node can change their topology frequently. So their study was carried on different mobile node movement pattern which are: Random Waypoint Mobility Model, Random Walk Mobility Model and Random Direction Mobility Model. In order to evaluate the performance of the protocol with these node movement patterns, performance metrics used were Routing overhead, Throughput and Packet delivery ratio. They used 2 simulation scenarios where in the first scenario comparison was made on different mobility model varying different number of nodes 5, 10, 15, 20, 25 with fixed speed of 15m/s and in other case comparison was made to evaluate the protocol on different mobility models with varying speeds 5, 10, 15, 20 m/s and 50 nodes as constant all through. They concluded that Random waypoint model is best for AODV compared to other mobility m odels as the protocol produces highest throughput than compared to others. Other related work from (Nyirenda, 2009) gives the similar working of MANET routing protocols AODV, OLSR, DSR and TORA on OPNET 14.5. Their work carried out for study the performance of the four protocols by different performance metrics which are: Network load, Packet delivery ratio, Packet end-to-end delay and Throughput. The simulation setup which was implemented on 6 different scenarios where the traffic passing on to the network was ranging from low to high network load, nodes changing from 5, 20, 50 and with speed ranging from 10 m/s to 28 m/s. Mobility model used in this was Random waypoint model for mobility pattern. They conclusions included in their work showed that OLSR performed better compared to the other protocols as it has a bad routing overhead and hence it is well suited for large and complex networks. So apart from routing overhead OLSR performed better but with routing overhead DSR is better. But when in small network AODV is much better compared to other protocol s. So finally, proactive protocols perform well in high capacity links whereas reactive protocols perform better in low capacity networks. From another paper (Maltz, 2001), we see that working on demand routing protocols in MANET was done where DSR protocol was compared to other on demand protocols like AODV, TORA and DSDV. Simulation setup carried is represented in tables below: With the above simulation setup the protocols were evaluated based on the performance metrics used which was Packet delivery ratio, Routing overhead, Path optimality and lower speed of nodes. The conclusions showed that DSR performed well when referred to packet loss rate and routing over head is concerned. Of all careful implementation done with all the above parameters tested on the experiment test beds DSR out performed in every case scenario used when compared all the other protocols used in this setup. 2.3 Background Work A network can be said as association of different systems or organizations where sharing the information can be done collectively. Whereas in computing terms it can be simply defined as a group of computers connected together logically to share information like printing, faxing, etc The network can be divided into 2 types based on their working behaviour. They are: Infrastructure network: These networks are used where the topology is said to be limited and there is a fixed point like base station (generally referred as router) to transmit signals and the end points which are connected to base station communicate with each other devices on the network switching from one base station to another. When a node moves out of range within its network, then it is said to be connected to another base station range where this process is referred as handoff. We can often see this type of mechanisms in infrastructure and fixed or wired networks. Infrastructure less network: These networks are a typical type of networks where there are no such fixed nodes or topologies on the network and the end pints or devices on the network are free to communicate with each other devices on the network as each device on the network behave themselves as routers and encourages communication process all over the network. By this we can say that wireless technology is a promising technology that can tolerate the information exchange worldwide. In the last decade we can also see the constant increase in the growth wireless technology issues, one of which being mobile devices such as laptops, cell phones, PDAs etc Ad hoc networks are also the part of this type of network. Mobile Ad hoc network is a new technology emerged with the hypothesis of wireless networks. These networks are very typical and do not use any fixed infrastructure for communication process. The nodes connected in these networks are wireless links which are mobile in nature and communicate with each other mobile node in the network with radio transmission and topology is said to establish by the intermediate nodes on the network which are helpful for communication process. As there are no fixed infrastructure and limited topology constraints the nodes on the network are free to join and leave the network and this is possible as the nodes on the network are mobile. Due to this random movement of the nodes in the network the topology of the network changes dynamically. Due to this change protocol must be able to acclimatize with these movements and are also responsible to maintain the routes of the information travelled without disturbing network connectivity. This concept of ad hoc network allows each node on its network to act like router, resulting in the flow of information exchange with multi hop routing. These types of networks are widely used in military and other rescue applications. (Saadawi, 2003) 2.4 Routing: Routing is the process of moving the data from one place of the network to another. The one end should be the source which intends to transfer the data to the destination (other end). The concept of routing has been there since 1970s but it has caught the move in 1980s. In 1970s networks were simple and today there are large scale networks in existence. To move the data from one host to another at least one router is required in the network. Router has all the information regarding hosts in the network and it can manipulate the best possible route as well. (Javvin, 2004) Routing takes place at Layer 3 in OSI 7 layer Model. Some of the protocols at layer 3 are IP and IS-IS. These protocols carry the data between source and destination along with their addresses in the data packet. Routing involves two basic activities; Path Determination and Switching. These two activities are capable to determine the optical routing path and to transfer the data packets through internetworking. This is called Switching. Switching can still be easy where as determining the reliable path is difficult. Path Determination: Routing make use of the different routing protocols to determine the best possible path to deliver the data. Routing protocols use the metric to calculate which the best possible path to accomplish the task is. The metric used could be path bandwidth, path length, delay etc. to determine the optimal path. To determine the path in the network, routing algorithms maintains the routing tables which are used to store the routing information about the network. Routers communicate with each other in order to maintain their routing tables which make communication easier and faster. Routing information can vary according to the routing algorithm used for the process. (Cisco, 2010) Switching: Apart from path determination, router shows one more activity; Packet Switching. Switching simply means forwarding the required data from one interface to the another in order to reach the destination. In this case, the data to be forwarded is packet. The next interface address is decided by using the destination address present in the packet. Though the nodes know the next hop address, they still need to know how to use it. So for that reason they use routing tables. The routing table throws the packet away when the destination is unknown. But when the destination is known routing table posses all the interface information forming the route to the destination. (2006) The next hop address could be another host or either it could be a router. According to ISO developed hierarchical terminology, the systems which have the capability to forward the data from the source to the destination are called Intermediate Systems (IS) and the systems which fails to do so are called as End systems (ES). When it is a router it follows the same procedure as this one, and if it is a host it simply forwards the packet. In packet switching, the Layer 3 address of the source and the destination remains the same to authenticate the original sender and the receiver. However the Layer 2 address (MAC) changes from router to router and from router to host which at last determines the destination host. (Cisco, 2010) 2.5 Ad hoc Networks An ad hoc network is a collection of many autonomous nodes connected together by radio waves and maintain the connectivity in decentralised manner. Wireless ad hoc networks are connected through wireless links so there is no need of any physical medium and hence contend of the medium is always there such as noise, interference and fading. On ad hoc networks each node functions as a node and a router itself. It simply means there is no need of an additional switch or a router to route the data and the control is given to the nodes themselves. (Yang Li, 2010) 2.6 Mobile Ad hoc Networks: A Mobile Ad hoc Network is an autonomous network formed by hundreds or thousands of nodes. These networks dont need any infrastructure as they can act as a node and router itself. They are free to move anywhere in the network and are connected through radio links. The only limitation with the MANETs is that they can communicate in a particular rage of the radio waves and outside the network they need some additional arrangements to communicate. To overcome this limitation the Intermediate Node or sometimes called as Relays are brought into picture. Intermediate nodes help in forwarding the packets to the destination. In MANET nodes are free to travel anywhere in the network, hence network topology cannot be fixed for such networks and it keeps changing depending on the current location of the nodes. (ANTDS, 2001) The fundamental differences between the wired networks and MANET are: Asymmetric Links Redundant Link Interference Dynamic Topology 2.7 Characteristics of MANETs There are several MANET routing protocols which should handle the several inherent characteristics of MANETs as follows as mentioned in (Subbarao)(Jain, 2005): Dynamic Topologies: Since the MANET is infrastructure less ad hoc networks, the nodes are free to move arbitrarily. The mobility of nodes may be random and so unpredictable. So the links between the nodes may be unidirectional or bidirectional at times. Bandwidth Constrained, Variable Capacity Wireless Links: Wireless links generally are bandwidth constrained. Since there is a lower capacity in wireless links as compared to the wired links, the traffic congestion is typical rather than different. Energy/Power Constrained Operation: Energy consumption is vital in MANETs as these nodes operate typically off power limited sources. Some or all nodes in MANETs rely on batteries. Limited Physical Security: Wireless networks like MANETs are more vulnerable with the security issues available with them. Issues like eavesdropping, jammer attack, spoofing and denial of service attacks must be carefully considered. 2.8 Need of MANET Routing Protocols A mobile ad hoc routing protocol is used to discover new routes and maintain the existing routes between the nodes in the network. MANET (Mobile Ad Hoc Network) is the collecting of mobile nodes which are present in random manner in the network has the capacity to communicate and exchange information effectively over the network by facilitating the intermediate nodes for their communication. The essential task of a MANET protocol is to create or discover the correct and efficient routes between the nodes so that information can be delivered accurately with respect to time. Route construction should be done with less overhead and minimal bandwidth consumption for effective communication. 2.9 Applications of MANETs Applications of MANETs can be used in many critical situations today and are increasing widely. There are many applications of MANETs today and some of them are mentioned here. An ideal application is for search and rescue operations. Such kind of operations is characterized by the networks without having an infrastructure present. One of the reasons for this may be because all of the equipment was destroyed or may be the region is too remote. Rescuer must be capable of communicating to use their energy fairly and also they must maintain the security. Carrying the equipments for communication that the rescuers are already using makes the job easier. The commercial application for MANETs includes computing everywhere which means the mobile devices are free to move anywhere in the network and yet it is possible to be in communication with the devices. The computers are allowed to forward the data to another computer or data networks may be extended far beyond the considered reach. Such networks may be more widely available and much easier in use. Another important application of MANETs is Sensor Networks. Sensor networks are composed of very large number of small sensors which are able to detect number of properties of the area, for example; temperature, pressure, toxins, pollutions etc. In this case, the capability of sensor network is much limited. So there is always need to forward data to the central computer and for this purpose they have to rely upon others in order to forward data to the central computer. The sensor networks individually are limited in their computing capabilities but together can be very effective and the key to future homeland security. But individual sensors because of their limited computing capabilities can prove prone to failure and loss. There are many other applications of MANETs like personal area networking where the communicating nodes may be mobile phones, laptops etc. Also this has a potential in military operations with the nodes of the network as soldiers, tanks and airplanes. Many more areas includes civilian environment to diverse taxi cab networks, conference rooms, boats and ships. (Bluetronix, 2006) 2.10 Classification of Routing Protocols According to (Jain, 2005), ad hoc routing protocols can be classified mainly into two categories: Table driven (proactive) Routing 2.10.1 Proactive (Table-Driven) Routing Protocols These routing protocols are similar to and come as a natural extension of those for the wired networks. In proactive routing, each node has one or more tables that contain the latest information of the routes to any node in the network. Each row has the next hop for reaching a node/subnet and the cost of this route. Various table-driven protocols differ in the way the information about a change in topology is propagated through all nodes in the network. (LinuxOnly) In proactive routing protocol each node maintains the up to date routing information of all nodes in the network. Here each node maintains the routing table and broadcast it when there is a change in network topology. As soon as source needs the route to the destination it can select from the routing table. The routing table is exchanged periodically by broadcasting to all nodes in the network to keep track of the new message even though the topology is not changed. Each nodes has the routing information of all nodes in the network though most of it undesired. Advantages of proactive protocols are that the communication experiences a minimal delay and routes are up to date. Disadvantage is that the routes are broken as a result of mobility of nodes. (Chang) Following are the examples of table driven protocols: GSR and OLSR and some other proactive routing protocols are FSR, HSR, ZHLSR, CGSR and WRP etc. 2.10.1.1 OLSR (Optimized Link State Routing) OLSR Protocol is based on traditional link state algorithm which supports point to point routing strategy. In this strategy the nodes keeps exchanging the information periodically in order to maintain the network topology within the network. OLSR is an optimization version of link state protocols. That means it keeps flooding the topological changes information to all the hosts across the network when happens. OLSR is also proved beneficial for the reason that it minimizes the size of each control message exchanged and also it avoids each node to rebroadcast during the updating of the routes. It uses the Multi Point Replaying (MPR) strategy to do the above task. For MPR strategy each node creates a set of all of its neighbouring nodes, generally called multipoint relays of the node, in the network to transmit the packet once again. Each node in the particular set can receive and process the packet but only cannot retransmit it. To use MRPs, each node has to keep broadcasting periodic ally to all one hop neighbours using hello messages. Another method to reduce the overhead is to provide the shortest path. When the time interval is reduced for the control messages transmission, it can prove more reactive to the topological changes (Kuosmanen). The implementation of OLSR protocol basically uses two control messages; Hello message and Topology Control (TC). The hello messages are to be sent only one hop away from the host and are used for finding the link state information and hosts neighbours. MPR selector sets are constructed with Hello messages which explain which host in the network has chosen this host to act as MPR and using the information the host can select its own set of MPRs. The Topology control (TC) messages are to be broadcasted across entire network about the advertised neighbours and it includes at least the MPR selector list. As OLSR is proactive approach and it keeps updating the routing table periodically, the TC messages are also broadcasted periodically and the hosts with MPR selector set can only forward the TC messages. There can also be MID message which is Multiple Interface Declaration message to declare that the announcing hosts can have multiple OLSR interface addresses. And again MID message are broadcasted throughout entire network and only by MPRs. 2.10.2 Reactive (Source Initiated) Routing Protocols These protocols take a lazy approach to routing. They do not maintain or constantly update their route tables with the latest route topology. Reactive routing is also known as on-demand routing. The Reactive Routing Protocols are also called as Source initiated Demand Driven protocols. They are called so because the routes are discovered only when needed by source. Source initiated on demand networks cerates routing only when desired by the source node. When source wants to communicate with destination then it invokes the route discovery mechanism to find the path to the destination. The route discovery process is completed once a route is found or all possible are identified. Once the rout is formed between source and destination it is maintained by a route maintenance procedure until the destination becomes inaccessible or the route is no longer desired. (Chang) These Examples of reactive routing protocols are dynamic Source Routing (DSR), Ad hoc on-demand distance vector routing AODV, ABR, SSA, CBRP, and RDMAR. 2.10.2.1 AODV (Ad hoc On Demand Distance Vector) Ad hoc On Demand Distance Vector protocol as the name implies it is an On Demand that is, Reactive Protocol. AODV is capable of both unicast and multicast routing. It is an on demand algorithm, it means that it builds routes between nodes only as desired by source nodes. It uses the concepts of DSR routing for route discovery and route maintenance and DSDV protocol for the concept of sequence number. It uses sequence number concept to ensure the freshness of routes. The ad hoc on-demand Distance vector algorithm facilitates the self-starting, multi hop and dynamic routing between participating nodes to establish and maintain an ad hoc network. AODV algorithm enables the nodes to find the routes for new destinations as and when they are needed and the nodes are not required to maintain the routes to the destination that are not in the part of active communication. It also enables the nodes in the formation of multicast groups and enables the nodes to respond quickly to link breakages and topological changes in the network thus the operation of AODV is loop free and thus avoids the Balham Ford count to infinity problem. AODV routing protocol is a simple and effective routing protocol for Ad hoc networks. It also uses the concept of hop by hope routing and sequence numbers from DSDV protocol. The following are the message types defined by AODV they are: Route request (RREQ), Route replies (RREP), Route error (RERR) and group hellos (GRPH) this message types are handled by UDP and IP header. The route request message format contains the following fields: Source address: the address of the node which originates the route request Source Sequence number: the current sequence number to be used in deciding the route for the source request Destination address: the address of the target node for which the route is initialized. Destination Sequence numbers: the sequence number received by source for route towards the destination. Broadcast ID: The sequence number by which a RREQ route request can be uniquely identified. Hop counts: the number of the hops to be taken from the source node to reach the destination node that handles the Route request. The Route Reply message format contains the following fields Destination address: the address of the destination node for which the route is abounded Destination sequence number: the destination sequence number related to the route Source address: the address of the source node that originates the route request Lifetime: the time for which nodes receiving the route reply considers the route to be valid. Hop counts: the number of hops to be taken from source to destination. The route error message format contains the following fields: Unreachable destination address: The address of the destination that has become unreachable due to link failure. (Arbia, 2008) In AODV the only nodes that take active participation in routing process are the nodes that sit in direct path between source and destination. The nodes which do not lie on active path do not take participate or maintain the routing table, thus AODV minimize the number of control messages sent between two nodes. As long as there is a valid routes between the source and destination for communication, AODV does not play any role and when a new route to a new destination is required and if the route to the destination does not exist only then the source node initialize the route discovery process by broadcasting the RREQ message to find the route to destination. The Mobile Ad Hoc Networks MANET Mobile Ad Hoc Networks MANET Abstract Mobile Ad Hoc Network (MANET) is a wireless network capable of autonomous operation. MANET routing has no fixed base station and hence nodes in the network are mobile and self configuring. A MANET is characterized by multi hop routing so that nodes are not connected to layer 2 but can communicate through layer 3 routing. In MANET every node is a potential router and the topologies are dynamic due to node mobility. This paper presents a comprehensive study of four MANET routing protocols ADOV (Ad Hoc On demand Distance Vector), DSR (Dynamic Source Routing), OLSR (Optimized Link State Routing) and TORA (Temporally Ordered Routing Algorithm). For experimental purpose six scenarios have been considered. These 6 scenarios are generated with 3 different traffic parameters namely high resolution video, light HTTP and high FTP load. This traffic was passed individually on to each scenario on 2 different node setup (20, 100 nodes). Finally, graphical evaluation of each protocol was based on t heir performances which are calculated on the basis of performance metrics used which are End to end delay, Network load and Throughput. Chapter 1: Introduction This chapter demonstrates a brief overview of the project. Now days in our day to day life we see so many changes around the world accelerating with respect to technology. In this technical world Internet has brought revolution in communication media. Communication is said to the method of information exchange either between two people or between two end users (in terms of computers). Communication is said to be done when a file or a message is passed over the medium among two people. Here the usage of internet comes into existence. Internet can be used as shared medium for information interchange between users around the globe. This information can be of any type: Short Message Mail File transfers Video Audio etc When these types of information are passed among internet, it uses either the wired media (for connecting users locally) or wireless media (for connecting locally or globally). When this information exchange is done the packets carry that information through the protocols available for the respective media to deliver the packet to the destination. This is the process of information exchange. In this paper, similar work is experimented over MANET (Mobile Ad Hoc Networks) [chapter 2] for information exchange using four different protocols. This setup was done internally over a virtual setup of networks using OPNET modeller 14.5. So the investigation of protocols is done based on the performance of each protocol. In the scenarios, each protocol is passed with 3 different types of traffics namely: High FTP load, High Resolution Video and Light HTTP Browsing. This thesis concludes the performance of four routing protocols towards through the end. Keywords: MANET, AODV, OLSR, TORA, DSR, OPNET Modeler 14.5. 1.1 Organisation of Thesis: This thesis gives an overview of how the project is organised with respect to each chapter. The very first chapter is Introduction of the Thesis, which shows a project idea and the tasks to achieve the goals. Second chapter Literature Survey which contains the studies and work which has been done previously by other authors on the related topics with the parameters used by them for their work. The scenarios used for my work are related somewhere by overall different results are taken with different parameters used. Again the classification and the background work of MANETs are explained following the comparison of MANET routing protocols. The parameters and scenarios used for my work are explained briefly with the simulation setup in chapter 3, Implementation. The results of the simulations and experiments performed are explained in chapter 4, Performance Evaluation and Design. The results are taken graphically which helps in comparing the results for routing protocols against the pe rformance metrics used to investigate the performance. The graphs are explained briefly in chapter 4. The results gathered with the help of scenarios in chapter 3 are concluded with the future work on the routing protocols in chapter 5, Conclusion and Future Work. Finally the supported documents for the project which helped in making the simulation and project start up is kept in Appendix A. And finally chapter 6 shows all the sources and references used for the thesis to help in achieving all the supported information and work. 1.2 Objective of Work The main objective of this work is to study the different routing protocols, which are developed for Mobile Ad hoc networks (MANETs), and to compare the different routing protocols by using simulation tool OPNET Modeler 14.5. As a part of the work four major routing protocols OLSR, AODV, DSR and TORA have been selected and carried out the simulations for comparing the performance of these protocols. Three performance metrics delay; Network Load and Throughput are used to compare the performance of the routing protocols. Objective 1 To get a clear understanding and functioning of different routing protocols for Mobile Ad hoc networks. This objective could be achieved by reading and understanding the various papers available on routing protocols of Mobile Ad hoc networks. Objective 2 To do a literature survey of previous work done on MANET Routing Protocols so that something different and efficient simulation could be introduced. For this objective different articles and papers published has been studied thoroughly and analysed from websites, books and all relevant resources available. By going through literature survey on routing protocols, the desired simulation environment and setup have been introduced with different simulation parameters. Literature Survey is explained in chapter 2. Objective 3 Conducting an experiment and collecting the output data: This objective has been achieved by designing the appropriate networks with the appropriate simulation parameters and running a simulation for different protocols for different performance metrics. After conducting the simulation the output data have been collected graphically. The results are shown graphically and explained in the project in chapter 4. Objective 4 Analyzing the output data and ending up with summary and the conclusion: The results have been studied and explained in chapter 4. After studying the simulation results conclusion has been made with some future work which can be done further. Conclusion of the project and future work is explained in chapter 5. Chapter 2: Literature Survey 2.1 Introduction This chapter gives a brief introduction about the work done in previous related papers and reports related to this project. In addition, the introduction to the routing protocols and their classification with respect to routing is demonstrated. This chapter is a short review of the previous work done and the additional objectives regarding routing protocols. The four MANET routing protocols are selected to evaluate the performances; they are OLSR, AODV, DSR and TORA. The further implementations of these protocols are explained later in this thesis (Chapter 3). MANET is an infrastructure less network which provides the freedom to the nodes to be free to move anywhere in the network (Stefano Basagni, 2004). 2.2 Related Work on Routing Protocols: As we see from (Mahmoud), analysis of two reactive protocols DSR and TORA were done using OPNET Modeller. In their simulation scenario, they used 50 wireless devices in each scenario with constant traffic parameters and protocol specification settings. They have passed FTP traffic of 1000 bytes making it constant throughout the simulation. Evaluation of these protocols was done based on the performance metrics used which are: Delay, Data dropped, Throughput and media access delay. Their simulation results shows that DSR performance was better than TORA in terms of throughput as TORA produces less throughput due to additional overhead used for path creation and path maintenance. At the same time TORA minimizes communication overhead by localization which results in less delay when compared to DSR as there is no such mechanism in DSR. Similarly, from (Zukarnain, 2009) they have done evaluation of MANET routing protocol AODV in order to establish the connection between the nodes since the mobile node can change their topology frequently. So their study was carried on different mobile node movement pattern which are: Random Waypoint Mobility Model, Random Walk Mobility Model and Random Direction Mobility Model. In order to evaluate the performance of the protocol with these node movement patterns, performance metrics used were Routing overhead, Throughput and Packet delivery ratio. They used 2 simulation scenarios where in the first scenario comparison was made on different mobility model varying different number of nodes 5, 10, 15, 20, 25 with fixed speed of 15m/s and in other case comparison was made to evaluate the protocol on different mobility models with varying speeds 5, 10, 15, 20 m/s and 50 nodes as constant all through. They concluded that Random waypoint model is best for AODV compared to other mobility m odels as the protocol produces highest throughput than compared to others. Other related work from (Nyirenda, 2009) gives the similar working of MANET routing protocols AODV, OLSR, DSR and TORA on OPNET 14.5. Their work carried out for study the performance of the four protocols by different performance metrics which are: Network load, Packet delivery ratio, Packet end-to-end delay and Throughput. The simulation setup which was implemented on 6 different scenarios where the traffic passing on to the network was ranging from low to high network load, nodes changing from 5, 20, 50 and with speed ranging from 10 m/s to 28 m/s. Mobility model used in this was Random waypoint model for mobility pattern. They conclusions included in their work showed that OLSR performed better compared to the other protocols as it has a bad routing overhead and hence it is well suited for large and complex networks. So apart from routing overhead OLSR performed better but with routing overhead DSR is better. But when in small network AODV is much better compared to other protocol s. So finally, proactive protocols perform well in high capacity links whereas reactive protocols perform better in low capacity networks. From another paper (Maltz, 2001), we see that working on demand routing protocols in MANET was done where DSR protocol was compared to other on demand protocols like AODV, TORA and DSDV. Simulation setup carried is represented in tables below: With the above simulation setup the protocols were evaluated based on the performance metrics used which was Packet delivery ratio, Routing overhead, Path optimality and lower speed of nodes. The conclusions showed that DSR performed well when referred to packet loss rate and routing over head is concerned. Of all careful implementation done with all the above parameters tested on the experiment test beds DSR out performed in every case scenario used when compared all the other protocols used in this setup. 2.3 Background Work A network can be said as association of different systems or organizations where sharing the information can be done collectively. Whereas in computing terms it can be simply defined as a group of computers connected together logically to share information like printing, faxing, etc The network can be divided into 2 types based on their working behaviour. They are: Infrastructure network: These networks are used where the topology is said to be limited and there is a fixed point like base station (generally referred as router) to transmit signals and the end points which are connected to base station communicate with each other devices on the network switching from one base station to another. When a node moves out of range within its network, then it is said to be connected to another base station range where this process is referred as handoff. We can often see this type of mechanisms in infrastructure and fixed or wired networks. Infrastructure less network: These networks are a typical type of networks where there are no such fixed nodes or topologies on the network and the end pints or devices on the network are free to communicate with each other devices on the network as each device on the network behave themselves as routers and encourages communication process all over the network. By this we can say that wireless technology is a promising technology that can tolerate the information exchange worldwide. In the last decade we can also see the constant increase in the growth wireless technology issues, one of which being mobile devices such as laptops, cell phones, PDAs etc Ad hoc networks are also the part of this type of network. Mobile Ad hoc network is a new technology emerged with the hypothesis of wireless networks. These networks are very typical and do not use any fixed infrastructure for communication process. The nodes connected in these networks are wireless links which are mobile in nature and communicate with each other mobile node in the network with radio transmission and topology is said to establish by the intermediate nodes on the network which are helpful for communication process. As there are no fixed infrastructure and limited topology constraints the nodes on the network are free to join and leave the network and this is possible as the nodes on the network are mobile. Due to this random movement of the nodes in the network the topology of the network changes dynamically. Due to this change protocol must be able to acclimatize with these movements and are also responsible to maintain the routes of the information travelled without disturbing network connectivity. This concept of ad hoc network allows each node on its network to act like router, resulting in the flow of information exchange with multi hop routing. These types of networks are widely used in military and other rescue applications. (Saadawi, 2003) 2.4 Routing: Routing is the process of moving the data from one place of the network to another. The one end should be the source which intends to transfer the data to the destination (other end). The concept of routing has been there since 1970s but it has caught the move in 1980s. In 1970s networks were simple and today there are large scale networks in existence. To move the data from one host to another at least one router is required in the network. Router has all the information regarding hosts in the network and it can manipulate the best possible route as well. (Javvin, 2004) Routing takes place at Layer 3 in OSI 7 layer Model. Some of the protocols at layer 3 are IP and IS-IS. These protocols carry the data between source and destination along with their addresses in the data packet. Routing involves two basic activities; Path Determination and Switching. These two activities are capable to determine the optical routing path and to transfer the data packets through internetworking. This is called Switching. Switching can still be easy where as determining the reliable path is difficult. Path Determination: Routing make use of the different routing protocols to determine the best possible path to deliver the data. Routing protocols use the metric to calculate which the best possible path to accomplish the task is. The metric used could be path bandwidth, path length, delay etc. to determine the optimal path. To determine the path in the network, routing algorithms maintains the routing tables which are used to store the routing information about the network. Routers communicate with each other in order to maintain their routing tables which make communication easier and faster. Routing information can vary according to the routing algorithm used for the process. (Cisco, 2010) Switching: Apart from path determination, router shows one more activity; Packet Switching. Switching simply means forwarding the required data from one interface to the another in order to reach the destination. In this case, the data to be forwarded is packet. The next interface address is decided by using the destination address present in the packet. Though the nodes know the next hop address, they still need to know how to use it. So for that reason they use routing tables. The routing table throws the packet away when the destination is unknown. But when the destination is known routing table posses all the interface information forming the route to the destination. (2006) The next hop address could be another host or either it could be a router. According to ISO developed hierarchical terminology, the systems which have the capability to forward the data from the source to the destination are called Intermediate Systems (IS) and the systems which fails to do so are called as End systems (ES). When it is a router it follows the same procedure as this one, and if it is a host it simply forwards the packet. In packet switching, the Layer 3 address of the source and the destination remains the same to authenticate the original sender and the receiver. However the Layer 2 address (MAC) changes from router to router and from router to host which at last determines the destination host. (Cisco, 2010) 2.5 Ad hoc Networks An ad hoc network is a collection of many autonomous nodes connected together by radio waves and maintain the connectivity in decentralised manner. Wireless ad hoc networks are connected through wireless links so there is no need of any physical medium and hence contend of the medium is always there such as noise, interference and fading. On ad hoc networks each node functions as a node and a router itself. It simply means there is no need of an additional switch or a router to route the data and the control is given to the nodes themselves. (Yang Li, 2010) 2.6 Mobile Ad hoc Networks: A Mobile Ad hoc Network is an autonomous network formed by hundreds or thousands of nodes. These networks dont need any infrastructure as they can act as a node and router itself. They are free to move anywhere in the network and are connected through radio links. The only limitation with the MANETs is that they can communicate in a particular rage of the radio waves and outside the network they need some additional arrangements to communicate. To overcome this limitation the Intermediate Node or sometimes called as Relays are brought into picture. Intermediate nodes help in forwarding the packets to the destination. In MANET nodes are free to travel anywhere in the network, hence network topology cannot be fixed for such networks and it keeps changing depending on the current location of the nodes. (ANTDS, 2001) The fundamental differences between the wired networks and MANET are: Asymmetric Links Redundant Link Interference Dynamic Topology 2.7 Characteristics of MANETs There are several MANET routing protocols which should handle the several inherent characteristics of MANETs as follows as mentioned in (Subbarao)(Jain, 2005): Dynamic Topologies: Since the MANET is infrastructure less ad hoc networks, the nodes are free to move arbitrarily. The mobility of nodes may be random and so unpredictable. So the links between the nodes may be unidirectional or bidirectional at times. Bandwidth Constrained, Variable Capacity Wireless Links: Wireless links generally are bandwidth constrained. Since there is a lower capacity in wireless links as compared to the wired links, the traffic congestion is typical rather than different. Energy/Power Constrained Operation: Energy consumption is vital in MANETs as these nodes operate typically off power limited sources. Some or all nodes in MANETs rely on batteries. Limited Physical Security: Wireless networks like MANETs are more vulnerable with the security issues available with them. Issues like eavesdropping, jammer attack, spoofing and denial of service attacks must be carefully considered. 2.8 Need of MANET Routing Protocols A mobile ad hoc routing protocol is used to discover new routes and maintain the existing routes between the nodes in the network. MANET (Mobile Ad Hoc Network) is the collecting of mobile nodes which are present in random manner in the network has the capacity to communicate and exchange information effectively over the network by facilitating the intermediate nodes for their communication. The essential task of a MANET protocol is to create or discover the correct and efficient routes between the nodes so that information can be delivered accurately with respect to time. Route construction should be done with less overhead and minimal bandwidth consumption for effective communication. 2.9 Applications of MANETs Applications of MANETs can be used in many critical situations today and are increasing widely. There are many applications of MANETs today and some of them are mentioned here. An ideal application is for search and rescue operations. Such kind of operations is characterized by the networks without having an infrastructure present. One of the reasons for this may be because all of the equipment was destroyed or may be the region is too remote. Rescuer must be capable of communicating to use their energy fairly and also they must maintain the security. Carrying the equipments for communication that the rescuers are already using makes the job easier. The commercial application for MANETs includes computing everywhere which means the mobile devices are free to move anywhere in the network and yet it is possible to be in communication with the devices. The computers are allowed to forward the data to another computer or data networks may be extended far beyond the considered reach. Such networks may be more widely available and much easier in use. Another important application of MANETs is Sensor Networks. Sensor networks are composed of very large number of small sensors which are able to detect number of properties of the area, for example; temperature, pressure, toxins, pollutions etc. In this case, the capability of sensor network is much limited. So there is always need to forward data to the central computer and for this purpose they have to rely upon others in order to forward data to the central computer. The sensor networks individually are limited in their computing capabilities but together can be very effective and the key to future homeland security. But individual sensors because of their limited computing capabilities can prove prone to failure and loss. There are many other applications of MANETs like personal area networking where the communicating nodes may be mobile phones, laptops etc. Also this has a potential in military operations with the nodes of the network as soldiers, tanks and airplanes. Many more areas includes civilian environment to diverse taxi cab networks, conference rooms, boats and ships. (Bluetronix, 2006) 2.10 Classification of Routing Protocols According to (Jain, 2005), ad hoc routing protocols can be classified mainly into two categories: Table driven (proactive) Routing 2.10.1 Proactive (Table-Driven) Routing Protocols These routing protocols are similar to and come as a natural extension of those for the wired networks. In proactive routing, each node has one or more tables that contain the latest information of the routes to any node in the network. Each row has the next hop for reaching a node/subnet and the cost of this route. Various table-driven protocols differ in the way the information about a change in topology is propagated through all nodes in the network. (LinuxOnly) In proactive routing protocol each node maintains the up to date routing information of all nodes in the network. Here each node maintains the routing table and broadcast it when there is a change in network topology. As soon as source needs the route to the destination it can select from the routing table. The routing table is exchanged periodically by broadcasting to all nodes in the network to keep track of the new message even though the topology is not changed. Each nodes has the routing information of all nodes in the network though most of it undesired. Advantages of proactive protocols are that the communication experiences a minimal delay and routes are up to date. Disadvantage is that the routes are broken as a result of mobility of nodes. (Chang) Following are the examples of table driven protocols: GSR and OLSR and some other proactive routing protocols are FSR, HSR, ZHLSR, CGSR and WRP etc. 2.10.1.1 OLSR (Optimized Link State Routing) OLSR Protocol is based on traditional link state algorithm which supports point to point routing strategy. In this strategy the nodes keeps exchanging the information periodically in order to maintain the network topology within the network. OLSR is an optimization version of link state protocols. That means it keeps flooding the topological changes information to all the hosts across the network when happens. OLSR is also proved beneficial for the reason that it minimizes the size of each control message exchanged and also it avoids each node to rebroadcast during the updating of the routes. It uses the Multi Point Replaying (MPR) strategy to do the above task. For MPR strategy each node creates a set of all of its neighbouring nodes, generally called multipoint relays of the node, in the network to transmit the packet once again. Each node in the particular set can receive and process the packet but only cannot retransmit it. To use MRPs, each node has to keep broadcasting periodic ally to all one hop neighbours using hello messages. Another method to reduce the overhead is to provide the shortest path. When the time interval is reduced for the control messages transmission, it can prove more reactive to the topological changes (Kuosmanen). The implementation of OLSR protocol basically uses two control messages; Hello message and Topology Control (TC). The hello messages are to be sent only one hop away from the host and are used for finding the link state information and hosts neighbours. MPR selector sets are constructed with Hello messages which explain which host in the network has chosen this host to act as MPR and using the information the host can select its own set of MPRs. The Topology control (TC) messages are to be broadcasted across entire network about the advertised neighbours and it includes at least the MPR selector list. As OLSR is proactive approach and it keeps updating the routing table periodically, the TC messages are also broadcasted periodically and the hosts with MPR selector set can only forward the TC messages. There can also be MID message which is Multiple Interface Declaration message to declare that the announcing hosts can have multiple OLSR interface addresses. And again MID message are broadcasted throughout entire network and only by MPRs. 2.10.2 Reactive (Source Initiated) Routing Protocols These protocols take a lazy approach to routing. They do not maintain or constantly update their route tables with the latest route topology. Reactive routing is also known as on-demand routing. The Reactive Routing Protocols are also called as Source initiated Demand Driven protocols. They are called so because the routes are discovered only when needed by source. Source initiated on demand networks cerates routing only when desired by the source node. When source wants to communicate with destination then it invokes the route discovery mechanism to find the path to the destination. The route discovery process is completed once a route is found or all possible are identified. Once the rout is formed between source and destination it is maintained by a route maintenance procedure until the destination becomes inaccessible or the route is no longer desired. (Chang) These Examples of reactive routing protocols are dynamic Source Routing (DSR), Ad hoc on-demand distance vector routing AODV, ABR, SSA, CBRP, and RDMAR. 2.10.2.1 AODV (Ad hoc On Demand Distance Vector) Ad hoc On Demand Distance Vector protocol as the name implies it is an On Demand that is, Reactive Protocol. AODV is capable of both unicast and multicast routing. It is an on demand algorithm, it means that it builds routes between nodes only as desired by source nodes. It uses the concepts of DSR routing for route discovery and route maintenance and DSDV protocol for the concept of sequence number. It uses sequence number concept to ensure the freshness of routes. The ad hoc on-demand Distance vector algorithm facilitates the self-starting, multi hop and dynamic routing between participating nodes to establish and maintain an ad hoc network. AODV algorithm enables the nodes to find the routes for new destinations as and when they are needed and the nodes are not required to maintain the routes to the destination that are not in the part of active communication. It also enables the nodes in the formation of multicast groups and enables the nodes to respond quickly to link breakages and topological changes in the network thus the operation of AODV is loop free and thus avoids the Balham Ford count to infinity problem. AODV routing protocol is a simple and effective routing protocol for Ad hoc networks. It also uses the concept of hop by hope routing and sequence numbers from DSDV protocol. The following are the message types defined by AODV they are: Route request (RREQ), Route replies (RREP), Route error (RERR) and group hellos (GRPH) this message types are handled by UDP and IP header. The route request message format contains the following fields: Source address: the address of the node which originates the route request Source Sequence number: the current sequence number to be used in deciding the route for the source request Destination address: the address of the target node for which the route is initialized. Destination Sequence numbers: the sequence number received by source for route towards the destination. Broadcast ID: The sequence number by which a RREQ route request can be uniquely identified. Hop counts: the number of the hops to be taken from the source node to reach the destination node that handles the Route request. The Route Reply message format contains the following fields Destination address: the address of the destination node for which the route is abounded Destination sequence number: the destination sequence number related to the route Source address: the address of the source node that originates the route request Lifetime: the time for which nodes receiving the route reply considers the route to be valid. Hop counts: the number of hops to be taken from source to destination. The route error message format contains the following fields: Unreachable destination address: The address of the destination that has become unreachable due to link failure. (Arbia, 2008) In AODV the only nodes that take active participation in routing process are the nodes that sit in direct path between source and destination. The nodes which do not lie on active path do not take participate or maintain the routing table, thus AODV minimize the number of control messages sent between two nodes. As long as there is a valid routes between the source and destination for communication, AODV does not play any role and when a new route to a new destination is required and if the route to the destination does not exist only then the source node initialize the route discovery process by broadcasting the RREQ message to find the route to destination. The

Symbolism and Loss of Identity in The Handmaids Tale by Margaret Atwoo

Symbolism and Loss of Identity in The Handmaid's Tale by Margaret Atwood In Margaret Atwood's The Handmaid's Tale, Offred recounts the story of her life and that of others in Gilead, but she does not do so alone. The symbolic meanings found in the dress code of the women, the names/titles of characters, the absence of the mirror, and the smell and hunger imagery aid her in telling of the repugnant conditions in the Republic of Gilead. The symbols speak with a voice of their own and in decibels louder than Offred can ever dare to use. They convey the social structure of Gileadean society and carry the theme of the individual's loss of identity. All the women in Gilead wear color-coded uniforms. The colors parade their social status and/or role in the reproductive process. The 'Aunts' who run the Rachel and Leah Re-Education Center wear brown; they are responsible for the indoctrination of the handmaids. The 'Marthas,' who wear green, are the servants. The 'Wives' wear a type of Virgin-Mary blue, which signifies their inability to bear children. The handmaids wear red robes and white peaked hats which resemble nuns' habits. Thus, they personify a religious sacrifice; they are like "temple prostitutes doomed to a kind of purdah in perpetuity" (Rigney 117). In addition, the red color of their clothing symbolizes their fertility. The color-coded uniforms that the women wear does more than just signify their functions. Along with the names/titles of characters, they symbolize the individual's loss of identity. No distinguishing mark of a woman is considered; rather, she is lumped with a group in which she is defined only by her social and reproductive function. Essentially, the color-coded uniforms strip each woman of her i... ...litical enemies. The foul and suffocating air of Gilead symbolizes the claustrophobia as well as oppression of its inhabitants (Rubenstein 109-110). In The Handmaid's Tale some symbolic tools such as dress codes and characters' names reflect the social standings of individuals in the Gilead society. These same symbols and others such as the mirror draw attention to the loss of individual identity, a theme present throughout the novel. Still others like smell or hunger convey the atmosphere&emdash;both physical and psychological&emdash;in Gilead. Whatever their different purposes may be, the symbolic devices achieve the same result: they enlighten the reader on dangerous social tendencies and compel him/her to take action in order to prevent the outcomes they depict. Works Cited Atwood, Margaret. The Handmaid's Tale. Anchor Books: New York, New York, 1985.

Travelling For Education

Due to the miserable situations of Lebanese students and their long years of suffering from the bad educating services and due to the absence of responsibility toward university students and the difficulty of finding jobs. The researcher in this paper shows the attention to this problem. Traveling For Education It was become a fashion trend that more and more people choose to go abroad to study. Some people think it is great experience while on the country , some others think it is not good at all!Despite of the importance of studying abroad and the presence of scientist that have raised Lebanon's name abroad , there are still oppositions to the views of this idea that prefer to stay in Lebanon despite of all its problems that they suffer from . Students in Lebanon should study outside for many reasons. General atmosphere is not suitable to study in Lebanon on all levels. The lack of raw materials in Lebanon led to the weakness of electricity and this case does not fit college studen t who needs a convenient means for study and research. In addition to the electricity obstacle we  notice the non-existence of laboratories, libraries and research centers, the state does not give an adequate attention to this deficiency, which leads for big effort toward the college student.For example , there is only one public library that opened new in Nabtieh † centre de lecture et d'animation culturelle † beside the red cross and it does not have the media support to be a know place to come to it. In addition to all problems that Lebanese students face we have an initial problem by students that is the lack of comfort in government universities , and when they resort  Ã‚  to private universities that are more comfortable with all they need for studying they will be shocked by the high cost that they can't afford which lead them to depression , and we will not forget the non-support for the best students that government must appreciate and have a look for them. Going abroad to study means far more than learning. The book† Intercultural journeys from study to residence abroad † ( Jackson , 1954) talk about this issue.This book focuses on the actual experiences of college students who travelled from their homes to foreign lands, the author  explores the linkage between intercultural awareness and sensitivity, language development , and identity reconstruction in young adult college learners. Generally, the first thing you need to do is to survive in a foreign nation. Where to find a place to live? How to deal with transportation? How to cook food? All these are the things you have to think and depend on yourself.Students who study abroad have to take care of themselves, and these questions are used the Lebanese students who don't want to travel abroad. Without parents, you can learn how to arrange their  own issues and do everything by yourself better. This is what we call independent awareness. Studying abroad cultivate your independent awareness and capability of taking care yourself. It is   always a tough time when living in a country that is totally new to you and facing all kinds problems. One you overcome them , you get the ability to live on your own. This is great, when the people of your age still enjoying their lives under the protection of their families, you begin to experience life.We take this factor as the most important advantage as it teaches you the basic ability to live your life. No one but yourself can teach you this! Everyone needs to be enriched with more experience and be more mature. Studying abroad means you set yourself into a circumstance that is totally different to you. You can enjoy a new culture all by yourself: people's thoughts and behaviors and the way people live are the first-hand to you , is not this great ? Cultural differences are more than just differences in language, food, appearances, culture and personal habits.A person's reflects very deep perceptions, be liefs, and values that influence his or her way of life and the way that he or she views the world. Students who experience cultural differences personally can come to truly understand where other cultures are coming from.You can greatly increase your adaptability to what we call the † Global Village† in your potential career ( Dixon , 2009 ) . Only knowing cultural difference is not enough, studying abroad has a lot more to explore! seeing the beautiful sceneries of a nation, volunteering   in social work and communicating with local people are all up to you. By studying abroad you know more about the world, no matter academically or physically. Knowing more a and experiencing more help you think rationally and behave maturely. The things above are the most important and valuable advantages we can think of. And of course there are much more that hat we mentioned , learning and mastering a new manage or having the chance to travel may also be the advantages that attrac t you. Do not hesitate, going abroad to study do offer you great improvement!

Free Essays on Economics of Marriage

The marriage expectations of 1898 are not a far cry from the worries of women in the present. In the past, there were many concerns of the economic value of a wife, whether it be abusing the wife’s free labor, or marrying into a rich family for the sake of money. As times have slowly changed, the argument has not. The women are still doing much of the non-market work, but now it depends on her bargaining strength. During the last decade, women have become concerned with the economical impacts on behavior, ranging from the intra-household distribution power to the distribution of wealth by gender at marriage. This brings me to the focus of this paper, I will discuss whether or not it is economically advantageous for a woman to become part of the marriage market. When men and women fall in love, relative incomes are not the only things factored into whether or not to marry, but they do play an important role. There are costs and benefits that help people make the marriage decision, such as income and assets, time, and intimacy. There are also tax and health benefits implications for not getting married. Likewise, there are costs of divorce such as married families tend to have more income and wealth compared to divorced families. The economic costs of marriage are that married families have more demands to meet with the resources they have, married people have greater potential for conflict on the use of those resources, and financial policies that they adopt will affect and be affected by the family relationships. If a woman decides to marry, there is a chance she may leave behind her career and earning potential for the emotional benefits of marriage. Myra Strober asks the question of â€Å"What’s a wife worth? What’s a wife worth in a marriage that started with zero assets, but after thirty years of marriage has assets of about $100 million, which came from the husband’s earnings and stock options? What’s the â€Å"equitabl... Free Essays on Economics of Marriage Free Essays on Economics of Marriage The marriage expectations of 1898 are not a far cry from the worries of women in the present. In the past, there were many concerns of the economic value of a wife, whether it be abusing the wife’s free labor, or marrying into a rich family for the sake of money. As times have slowly changed, the argument has not. The women are still doing much of the non-market work, but now it depends on her bargaining strength. During the last decade, women have become concerned with the economical impacts on behavior, ranging from the intra-household distribution power to the distribution of wealth by gender at marriage. This brings me to the focus of this paper, I will discuss whether or not it is economically advantageous for a woman to become part of the marriage market. When men and women fall in love, relative incomes are not the only things factored into whether or not to marry, but they do play an important role. There are costs and benefits that help people make the marriage decision, such as income and assets, time, and intimacy. There are also tax and health benefits implications for not getting married. Likewise, there are costs of divorce such as married families tend to have more income and wealth compared to divorced families. The economic costs of marriage are that married families have more demands to meet with the resources they have, married people have greater potential for conflict on the use of those resources, and financial policies that they adopt will affect and be affected by the family relationships. If a woman decides to marry, there is a chance she may leave behind her career and earning potential for the emotional benefits of marriage. Myra Strober asks the question of â€Å"What’s a wife worth? What’s a wife worth in a marriage that started with zero assets, but after thirty years of marriage has assets of about $100 million, which came from the husband’s earnings and stock options? What’s the â€Å"equitabl...

Gattaca Why Vincent Has Exceeded His Potential Essays

Gattaca Why Vincent Has Exceeded His Potential Essays Gattaca Why Vincent Has Exceeded His Potential Paper Gattaca Why Vincent Has Exceeded His Potential Paper Gattaca is a science fiction film written and directed by Andrew Niccol. It is about a mans struggle to follow his dream despite being pre-determined by the society in which he lives to not be able to achieve it. Gattaca shows that people can in fact exceed the potential that society and their genes place on them. This is seen in the characters of Vincent and Director Joseph who both exceed their expected potential. Director Josephs claim that humans cannot exceed their potential when referring to the navigators at Gattaca is clearly false because Vincent and has infact exceeded his potential. Vincent is concieved naturally without the help of genetic engineering technology which gives geneticists the ability to choose, what genes they want to keep in the fetus and what genes they want to eliminate based on the parents choice and budget. Because he is concieved naturally which is considered an unorthodox form of reproduction by Vincents society, he is born with a high probability of many genetic problems and defects such as manic depression, attention deficit disorder, heart disorder, myopia and is born with a life expectancy of 30. years. As Vincent grows older he falls in love with the cosmos and decides to pursue a career in space but is quickly rebuked by his parents because of his inferior genetic characteristics specifically his heart disorder. Despite this negative feedback from his parents he decides to apply at Gattaca hoping that he wont be discriminated against because of his genetic profile. However Vincents hope shatters as his application is declined, and is forced to work as a cleaner at Gattaca. : When his fellow workmate asks him why he cleans the screen immacutely he responds arrogantly by saying If the glass is clean, itll be easier for you to see me when im on the other side of it. Because he is not following his dream, Vincent decides to become a barrowed ladder which is a person who uses the genetic identity of another for a purpose such as getting a particular job or in Vincents case getting into Gattaca. Vincent borrows the indentity of Jerome Morrow a professional swimmer born genetically engineered up to perfection. Jerome has been hit by a moving vechicle which has paralyzed him from the waist down and thus making him unable to swim anymore. Jerome Morrow supplies Vincent with blood, urine, hair and skin samples so that he is able to get into Gattaca. Vincent passes the interview which is a urine test, and quickly becomes one of Gattacas elite navigators and achieves his dream of going to space, despite being born with genes that pre-determined him to be lower and inferior member of society, he manages to chieve the impossible getting into a prestigious space academy and achieves his dream of becoming a space navigator. Vincent however is not the only one who has exceeded his genetic potential. In the society in which Vincent lives, the elite or the people with the perfect genome are considered to be not only genetically perfect but also morally perfect. An example of this is depicted vividly in the movie when Vincents eyebrow sample containing invalid genes is found near the crime of the murderer mission director. Vincent is quickly regarded as the main suspect in the crime simply because is an invalid a person born naturally through sexual intercourse. The assumption that is made is that people who are valids or people who have perfect genes cannot commit an imperfect immoral act such as murder and therefore the main suspect has to be by definition an invalid. This assumption however is false because the person responsible for the murder turns out to be Director Joseph himself. Director Joseph is a good example of a person who exceeds his potential by comiting an act of murder. Before Joseph is convincted of murder and while he was being questioned he told the detectives that There isnt a violent bone in my body which is a classic manifestation of what how Vincents society views people with perfect genes as morally perfect people. Because Direct Joseph has in a sense rebelled against his genes (assuming that morality is a genetic characteristic) he has exceeded his potential and proves that perfect genes does not necessarily equal high rectitude. In conclusion, the film Gattaca shows that people can and do exceed their potential. This is seen in the characters of Director Joseph and Vincent who both exceed the potential that society has given them. Vicent exceed his potential by getting into Gattaca even though he is born genetically inferior and considered a lower class member of society while Director Joseph exceeds his potential by commiting the act of murder which is not expected and not programmed in his genes.

Despite His Mean and Miserable Ways, We Never Completely Dislike Scrooge. Discuss. Essay Essay Example

Despite His Mean and Miserable Ways, We Never Completely Dislike Scrooge. Discuss. Essay Essay Example Despite His Mean and Miserable Ways, We Never Completely Dislike Scrooge. Discuss. Essay Essay Despite His Mean and Miserable Ways, We Never Completely Dislike Scrooge. Discuss. Essay Essay Despite his mean and suffering ways. we neer wholly dislike Scrooge. Discuss. A Christmas carols by CHARLES DICKENS. it’s non merely about the manner that scrooge act as ungenerous and wretch. but it’s besides a opportunity of given to do niggard transformed to a generous and sort individual. Readers denied being ever hatred about niggard. This can be separate to both sides. First scene niggard did move as tight-fisted and cold-hearted to others. the manner his talk and act makes audience disgusted. But when looking back for his yesteryear. the reader understands he has a difficult childhood experience. Unfortunately niggard was ever been forgotten. therefore the audience feels sorry for him. Oppositely. by giving a opportunity to Scrooge to salvation and transformed to a charitable and generous gentleman. At the get downing the audience hated Scrooge. because of his cold-hearted and mean-spirited tightwad. â€Å"Oh! But he was tight-fisted adult male at the grindstone. Niggard! A squeeze. twisting. hold oning. envious old evildoer! Hard and crisp as flint. from which no steel had of all time struck out generous fire ; secret. and self-contained. and lone as an oyster† he is really obstinate and doesn’t wanted to listen to his nephew Fred’s advice. and neer alter his head to accept other and besides to alter his ain destiny. Besides he is selfishness about ignore those hapless people. â€Å"If they would instead decease. † said niggard. â€Å"they had better make it. and diminish the excess population. † Scrooge doesn’t attention about other people’s decease. and he’s greedy as snake pit non even pass money to observe Christmas clip. Besides he has a large house but inside the house is dark and cold. like his ain personality cold- heated and mean. But after phantom Teach him a lesson. so he get down to alter and becomes otherwise. Scrooge learns the of import value about the household and relationship. Throughout the lesson that shade has been learning. eventually Scrooge understand the true significance of Christmas. and do himself alter the behavior that he has got on the old Christmas twenty-four hours. Best illustration he should larn is Bob’s household. Bob is his day-to-day employee. although his household is non rich plenty ( earn 20 shilling per hebdomad ) . but they are much happier than Scrooge. Merely â€Å"small pudding† makes the whole household so happy to sit together and to hold a great dinner during the Christmas Eve. Skinny illness Tiny Tim sitting at table corner. his passionate of love â€Å"God bless us everyone† makes scrooge feel so warmth and touchful. When speaking about the relationship Fred is a good illustration to speak about. He is so warmth and keeps Christm as in his bosom every twelvemonth. Every twelvemonth he invites a batch of friends and comparative to his house to observe Christmas. The relationship with each relation and friends all people comes together to observe on the Christmas. Fezziwig scrooge’s once employer makes himself believing back about old on the job clip. The manner fezziwig’s generous behavior besides influences Scrooge deeply. Learning Fezziwig maintaining Christmas every twelvemonth in his bosom and invite tonss of friend to hold dinner. The relationship between employer and employee is non ungenerous with lone attentions about the money and work. Fezziwig allowing his employer to hold yearss off during the Christmas clip it makes sense the true significance of Christmas clip and relationship between others. Throughout phantom’s lesson Scrooge understand to hold a large house and earn batch of money for no usage this is a shame and no good. and to hold these money to donate and assist the h apless is the best pick for Scrooge. Scrooge is redeems and larn to be liberally donate money to the hapless. Reader feels so excite about Scrooge alteration and assisting the society to increase the population. After he know that many hapless people like Tiny Tim is enduring and deceasing in the street. he couldn’t be so careless any longer. because this good decidedly act upon his hereafter or decease. He understand that if he maintain ignore those people and became so ungenerous so the effect that he would acquire is been loner everlastingly. and people would disrespect to him after him decease. Therefore he takes action about assisting Tiny Tim and besides donates a batch of money to those hapless people. Bach from Scrooge’s childhood clip it seems really hard. The audience feel so regretful to Scrooge. because they know the long term consequence to makes Scrooge alterations to such a greedy and selfish individual. by the manner to give this chance to deliver and alter niggard. originate niggard to mak e those contribution and good thing would alter his ain destiny and do the audience start to wish him. Life is ever like that. frequently people learn for each of different age clip. and besides learns from those errors. Scrooge did it! He transform to a generous. and charitable as everyone know! There are both manner. both good and bad. Scrooge diminishing his bad wont and action. therefore the audience reallylike the manner scrooge transform to a â€Å"second Christmas Father† . The manner he wake up becomes so happy and generously contribution. but besides at the start the readers did hatred about barbarous action and looking that niggard have.

Swine Flu Research Paper Example | Topics and Well Written Essays - 1000 words

Swine Flu - Research Paper Example   The article states that the 2009 outbreak of the disease was a pandemic and now after 4 years it is occurring widely in different states. Swine flu was originally a respiratory disease found in pigs. The article further gives an overview of the conditions of the states affected. The State of California has been affected most severely with 243 deaths which were higher than the previous year. In San Francisco, the hospitals are flooded with patients with flu symptoms, and to prevent any chances of communicability tents were set in the gardens of hospitals for such patients. The article reported that the death of a woman in Sacramento by this disease created a buzz among people. The woman died within 3 days of the appearance of symptoms but she did not get an injection for the flu. The article also explained the views of some doctors who explained that the disease is worrisome and it has been included in the flu vaccines, but the efficacy of the vaccine is 50-70 %. The article concl udes by stating that the reoccurrence of such disease makes the flu vaccination a mandatory, and the strains of H1N1 occurring in America are more virulent than anywhere in the world. Swine flu was an epidemic disease but it’s become a pandemic (Cha, 2014). The epidemiological triangle of the disease involves an agent, environment and host. According to the article, the agent that caused the disease was the virulent virus H1N1 and its strains. The outbreak of the disease was seasonal as it surfaced in the flu season.  

Compare Chinese monster and American monster Essay - 1

Compare Chinese monster and American monster - Essay Example Although many Chinese still believe that Nian exists, it has never appeared in the community or to a human again. Today, many of the Chinese light fireworks, as well as beat drums and gongs to drive the monster away. Modern people living in major towns and cities are the most notorious with the annual Spring Festival in commemoration of Nian the monster (Wong 27). In addition, the day signifies what most Chinese consider the unprecedented breakthrough after some villagers successfully tamed a horrible, ferocious monster that intimidated, attacked or even killed innocent people. Incidentally, tribulations of the village and the ultimate breakthrough forms the basis of contemporary traditions and customs associated with beating of drums, wearing red outfit and lighting of fireworks. The two other articles focus on Momo, an American monster. Momo (also known as the Missouri Monster) is hairy and foul-smelling (Hamilton 16). In general, the key differences between Nian and Momo highlight the fundamental cultural variation between China and the United States of America. The Big Book of Missouri Ghost Stories (2013) by Troy Taylor examines and analyzes the circumstances leading to the discovery of Momo the Missouri Monster. Apart from Momo, the article analyzes various legends and ghostly tales of Missouri (Taylor 130). In addition, the article asserts that most of the legends and ghostly tales consist of a mystery, bloodshed, and tragedy. Taylor further states that copious other stories about Missouri have since been lost in time, hidden or remained secret. Although a number of legends seem to have significantly impacted villages, towns and states, Americans do not take them seriously unlike the Chinese (Taylor 130). Louisiana residents have never considered the day some residents purportedly saw Momo special in their cultural history. Nevertheless, a few have forgotten the mystery and tribulations surrounding the reports about sightings of the

Goldman Sachs Term Paper Example | Topics and Well Written Essays - 2250 words

Goldman Sachs - Term Paper Example 2.A.i. Key Products and Services 7 2.A.ii.Function of Products and Services in the World of Investments 7 2.A.iii. Goldman Sachs’ Role in IPOs 8 2.B. Goldman Sachs’ Influence on the Capital Markets 8 2.B.i. Positive Influences 8 2.B.ii. Debated Influences Among Investors and other Firms/Companies 9 3. Role of Goldman Sachs in China 10 3.A. Key Investment Areas in China 10 3.A.i. Key Areas of Interest of Goldman Sachs in China 10 3.A.ii. Successful Cases/Engagements in China 11 3.B. Valuing China’s Present Economic Situation 11 3.B.i. Current Investment Climate in China- Views 11 3.B.ii. Forecasts for Future Prospects in China 11 4. Conclusion 12 4.A. Goldman Sachs’ Performance in the World of Investments 12 4.B. Goldman Sachs’ Role in China 12 References 13 1. Introduction to Goldman Sachs 1.A. Goldman Sachs History Goldman Sachs is an American investment bank that has its roots in Manhattan in New York City, having been founded there in 1869, with its key competencies being in general investment banking, financial services, the management of investments, and securities. It leads the world in the management of mergers and acquisitions, the provision of services tied to underwriting, the management of assets, as well as prime brokerage services that it is able to provide to individuals, companies, and countries. Once unassailable and with a pristine reputation built over its lifetime, the bank had seen its reputation and standing in the banking community tarnished as a result of its actuations during the financial crisis that erupted from 2007 and whose after effects are still being felt up to the present day. From its founding by Marcus Goldman in 1869, the firm emerged by the early part of the 20th century as one of the premier banking entities in the US, with expertise and market leadership in the establishment of the market for initial public offerings or IPOs. It was during the time after that, however, that the firm evolved from a trading company to an investment banking entity. The firm further evolved and developed into the 1999’s, to the point where it was able to launch its IPO of its own shares in 1999, transferring about 12 percent ownership of the firm into the hands of the investing public. Throughout this time and after, key personnel in Goldman Sachs went on to become key public officials managing the nation’s finances, as well as key executives in some of the country’s and the world’s major financial institutions, including Merrill Lynch and Citigroup. On the other hand, the controversies surrounding the alleged role of Goldman Sachs in inducing the financial crisis in 2007 and of aggravating the crisis have largely resulted in the reputation and fortunes of the investment bank being heavily hit in recent years, putting into doub t even its future prospects as a going concern and as a bastion of the capitalist system (Answers Corporation, 2012; Google, 2012; Thomson Reuters, 2012; Goldman Sachs, 2012; Taibbi, 2011; Taibbi, 2009; Smith, 2012). 1.B. Goldman Sachs Background The key activities of Goldman Sachs worldwide revolve around the management of investments, investment banking and securities management, as well as the provision of related financial services to countries, rich people, individuals, as well as corporations and other related entities. Its four business segments reflect its core businesses, which are Investment Management, Lending and Investing, Investment Banking, and Institutional Client Services. It has presence in key financial centers all over the world by way of vital offices, while being present likewise in a total of 30 countries Its key officers are the following (Google, 2012; Reuters Thomson, 2012): Lloyd C. Blankfein Chairman of the Board, Chief