Coffee Drinking Habits in UK Assignment Example | Topics and Well Written Essays - 2000 words

Coffee Drinking Habits in UK - Assignment Example UK's market is predominately penetrated by tea and fruit juices and tea is the third largest non-alcoholic beverage used in the country. However, trends are changing as a new coffee culture is emerging in the country. Most and most consumers now prefer coffee because of the relaxed experience offered by the branded coffee chains. Initially, the trends emerged in the urban areas of the country however, it is picking up in the rural areas also thus the future may provide a much bigger market to cater. It is however, important to note that due to current economic crisis in the country with the possibility of negative growth in 2009, the consumers may reduce their spending on something which can be produced in their own homes too. It is also critical to note that consumers are increasingly becoming ethical in nature and prefer such organizations which offer products and services which are based on the sustainability products. As discussed in the case study that Starbucks leave its water taps open all the time give the whole issue a more ethical dimension and indicate that the future consumer buying patterns may be shift towards having more ethically responsible organizations with an strong sense of conserving the natural resources of the planet. Starbucks is predominately American in taste and it has been strong speculated that the growth can doubled if the taste is tailored according to the European flavor preferred in EU region. Europe, as a region has a very strong tradition of drinking coffee according to their own individual tastes and consumers are certainly missing that element into the coffee cup offered by Starbucks thus the product development trends may be directed towards creating the coffee tastes which suit the European consumers. Significance to Starbucks The market intelligence or market research is critical for the success of the firm because it provides them a larger base of information to decide upon where to invest or not thus market information basically provides insight into as to how to spend their money wisely and the information is used to the maximum benefit of the firm. (Callingham).From a marketing perspective, understanding the market is one the key steps in order to make an entry into the market. Understanding the market therefore provide a deeper insight into the size of the market. Based on this, marketers often tend to segment the same into different niches according to their individual target market based on different factors such as demographics, psychographics etc. As discussed above that almost 20 million people living in UK belong to working class with different levels of incomes earned therefore Starbucks has virtually a market which has 20 million customers to satisfy and with the increase in trends for preferring coffee over the traditional non-alcoholic drinks such as tea and fruit juices, the

Comment Paper on Death of a Salesman Essay Example | Topics and Well Written Essays - 750 words

Comment Paper on Death of a Salesman - Essay Example Miller’s own early life was eerily similar to that of what the reader is made aware of Willy Loman’s life. For instance, Miller grew up in an upper-middle class neighborhood in New York City; the son of Polish Jewish immigrants. Miller’s own father was a successful businessman in a textile mill; which eventually employed 400 individuals. This successful lifestyle enabled the family to enjoy the luxuries of having a new car at a time when cars were still a novelty, attending private schools, and enjoying the occasional vacation. However, the good times would not last as the crash of 1929 and the onset of the Great Depression shattered the family’s bliss. Miller’s father, out of work and out of options sold their home and moved to Gravesend, New York. It was during this time that young Arthur Miller was forced to take a bread route ever morning before school; delivering bread via his bicycle as a means to keep the family afloat. Although it is easy to say that such an experience doubtless had an effect on how Arthur Miller viewed the plight of the average man, this author would go a step further and claim that the hard times and difficult experiences that young Arthur Miller endured during the great depression and his family’s subsequent fall from wealth are autobiographically sketched in his play â€Å"Death of a Salesman†. If one adopts this autobiographical approach to â€Å"Death of a Salesman†, many of the intrinsic lessons and interplay that exists between the family members and Willy Loman help to show the fleeting nature of success and the cold, cruel reality of pervasive failure that crushes the spirit of the entire family. As a means of showing this dichotomy, Willy Loman states, â€Å"Work a lifetime to pay off a house. You finally own it, and there’s nobody to live in it† (Miller 15). Rather than simply relating to the reader how difficult success is to achieve, Miller works to add a nuanced level of understanding which shows that even if success is achieved – what merit does it have in and of itself? The fleeting nature of success as defined by Loman in the above passage profoundly reflects the eventualities that effected Arthur Miller’s own young life with respect to the brief success enjoyed and then snatched away by the Great Depression. Further, strong elements of the Depression Era mentality peak through at various points of Arthur Miller’s play. When speaking with his wife Linda, Willy blurts out, â€Å"Once in my life I’d like to own something that isn’t broken already† (Miller 73). The rage and frustration at being perennially stuck with second best, having to live on the fringes of society, living with inferior products as a result of being poor is seen as a central theme throughout the play. More than merely representing poverty and hardship as the life of a salesman, this form of life alteration to deal wit h the gnawing pangs of poverty shows an author who is all too familiar with such an eventuality. Further, due to the aforementioned fact that Miller himself had to take a bread right prior to school every morning shows the extent to which the author had to sacrifice of himself as a means of helping to keep his own family sheltered, clothed, fed, and warm during a similarly trying time. However, more than being allegorical of the plight of the poor, the author

The Characteristics And Applications Of Manets Computer Science Essay

The Characteristics And Applications Of Manets Computer Science Essay Chapter 1 The advent of ubiquitous computing and the creation of new, powerful, efficient, portable computing devices have focused the importance of mobile and wireless networking. Mobile wireless communications and networking is an emerging technology that allows users to access information and services electronically at any time, regardless of their geographic positions. There are two types of wireless networks: infrastructure based wireless networks and infrastructure-less wireless networks (ad hoc networks). The infrastructure based wireless networks have routers and gateways as stationary components to which mobile nodes within the network connect. Mobile nodes connect to the nearest base station whose communication radius covers the area that the nodes are in. When a mobile node moves out of the coverage area of a base station, it is handed off to a new base station that covers the area that the node is now in. Cellular phone technology is a typical example of an infrastructure network. The second type of wireless network is the ad hoc network. The term ad hoc tends to different forms and can be mobile, stand alone, or networked[1]. A Mobile Ad hoc NETwork (MANET) is a self-organized wireless communication short lived network that contains collection of mobile nodes. The mobile nodes communicate with one another by wireless radio links without the use of any pre-established fixed communication network infrastructure or centralized administration, such as base stations or access points, and with no human intervention [2, 3, 5, 6, 7]. Self-organizing means that MANETs have the ability to spontaneously form a network of mobile nodes or hosts, merged together or partitioned into separate networks on-the-fly depending on the networking needs and dynamically handle the joining or leaving of nodes in the network. The major objectives of self organized MANET are: scalability, reliability, and availability. Mobile nodes are low capacity autonomous computing devices that are capable of roaming independently. Because of the fact that nodes are mobile, the network topology changes rapidly and unpredictably over time. Each mobile node acts as both a host and a specialized router to relay information (forward packets) to other mobile nodes. The success of the communication highly depends on the other nodes cooperation. The nodes themselves are responsible for dynamically discovering other nodes to communicate in radio range. Figure 1.1: Heterogeneous Mobile Ad hoc Network (MANET) Typical MANET nodes are Laptops, PDAs, Pocket PCs, Cellular Phones, Internet Mobil Phones, Palmtops or any other mobile wireless devices. These devices are typically lightweight and battery operated. Figure 1.1 illustrates an example of a heterogeneous MANET and its communication technology which contains one PDA, one pocket PC, one laptop, one mobile phone and one mobile device. Since mobile phone is outside pocket PCs transmission range, the data from pocket PC to mobile phone must be retransmitted by laptop. 1.1.1 Characteristics of MANETs The main characteristics of MANETs are: the complete lack of centralized control, lack of association among nodes, rapid mobility of hosts, frequent dynamically varying network topology, shared broadcast radio channel, insecure operating environment, physical vulnerability and limited availability of resources, such as CPU processing capacity, memory power, battery power, and bandwidth [2, 6, 7, 8]. Dynamic Network Topologies: The nodes in MANETs are free to move independently in any direction. The networks wireless topology may change frequently and randomly at unpredictable times and primarily consists of bidirectional links. Low Bandwidth: These networks have lower capacity and shorter transmission range than fixed infrastructure networks. The throughput of wireless communication is lesser than wired communication because of the effect of the multiple access, fading, noise, and interference conditions. Limited Battery Power: The nodes or hosts operate on small batteries and other exhaustible means of energy. So, energy conservation is the most important design optimization criteria. Decentralized Control: Due to unreliable links, the working of MANET depends upon cooperation of participating nodes. Thus, implementation of any protocol that involves a centralized authority or administrator becomes difficult. Unreliable Communications: The shared-medium nature and unstable channel quality of wireless links may result in high packet-loss rate and re-routing instability, which is a common phenomenon that leads to throughput drops in multi-hop networks. This implies that the security solution in wireless ad hoc networks cannot rely on reliable communication. Weak Physical Protection: MANETs are more prone to physical security threats than fixed-cable nets. Mobile nodes are usually compact, soft and hand-held in nature. Today, portable devices are getting smaller and smaller. They could get damaged or lost or stolen easily and misused by an adversary. The increased possibility of different types of attacks should be carefully considered. Scalability: Due to the limited memory and processing power on mobile devices, the scalability is a key problem when we consider a large network size. Networks of 10,000 or even 100,000 nodes are envisioned, and scalability is one of the major design concerns. 1.1.2 Applications of MANETs There are many applications of MANETs. The domain of applications for MANETs is diverse, ranging from small, static networks that are constrained by power sources to large-scale, mobile, highly dynamic networks. Significant examples include establishing survivable, efficient, dynamic communication for: network-centric military/battlefield environments, emergency/rescue operations, disaster relief operations, intelligent transportation systems, conferences, fault-tolerant mobile sensor grids, smart homes, patient monitoring, environment control, and other security sensitive applications. Most of these applications demand a specific security guarantees and reliable communication [2, 5, 7, 9]. Some well known applications are: Military Tactical Operations: For fast and possibly short term establishment of military communications and troop deployments in hostile and/or unknown environments. Search and Rescue Operations: For communication in areas with little or no wireless infrastructure support. Disaster Relief Operations: For communication in environments where the existing infrastructure is destroyed or left inoperable. Law Enforcement: For secure and fast communication during law enforcement operations. Commercial Use: For enabling communications in exhibitions, conferences and large gatherings. For some business scenarios, the need for collaborative computing might be more important outside office environments than inside a building. After all, it is often the case where people do need to have outside meetings to cooperate and exchange information on a given project. 1.1.3 Routing in MANETs Node mobility has a large impact on the behavior of ad hoc networks. The nodes in the network are free to move independently in any direction to change the routes. Every node in MANET acts as a router that discovers and maintains routes in the network. The nodes themselves are responsible for dynamically discovering other nodes to communicate. When a node wants to communicate with a node outside its transmission range, a multi-hop routing strategy is used which involves some intermediate nodes. The networks wireless topology changes frequently and randomly at unpredictable times. In order to allow truly spontaneous, infrastructure-less networking and efficient end-to-end communication with the network of nodes, a routing protocol is used to discover the optimal routes between the nodes. Hence, the primary challenge is to establish a correct and efficient route between a pair of nodes and to ensure the correct and timely delivery of packets. The routing protocols meant for wired networks cannot be used for MANETs because routing in MANETs is nontrivial due to the highly dynamic nature of the mobile nodes. Route construction should be done with a minimum of overhead and bandwidth consumption. An extensive number of research works on designing the various routing protocols proactive, reactive, and hybrid have been proposed in the literature and widely evaluated for efficient routing of packets [3]. However, they do not address possible threats aiming at the disruption of the protocol itself and often are vulnerable to node misbehavior. A node dropping all the packets is considered as malicious node or selfish nodes. A malicious node misbehaves because it intends to damage network functioning. A selfish node does so because it wants to save battery life for its own communication by simply not participating in the routing protocol or by not executing the packet forwarding. A malicious node could falsely advertise very attractive routes and thereby convince other nodes to route their messages via that malicious node. With the lack of a priori trust between nodes, current ad hoc routing protocols are completely insecure and optimized only to spread routing information quickly as the network changes [4]. 1.1.4 Security in MANETs Security is an essential service for MANET because all network services are configured on-the-fly. When the security of a given MANET architecture is not properly designed from the beginning, it is difficult to achieve the security goals in practical networks during the network deployment [12, 13]. To secure a MANET, one usually considers the objectives confidentiality (privacy), availability, integrity, authenticity and non-repudiation. Confidentiality ensures that secret information in the network is never revealed to unauthorized nodes. i.e. the assurance that data is not disclosed to unauthorized parties. Availability ensures that the requested network services, such as bandwidth and connectivity, are available in a timely manner and service is not denied to authorize users. i.e. the assurance that data is readily accessible. Integrity ensures that message or packet being transferred between nodes is not altered or corrupted. i.e. the assurance that data is genuine. Authentication ensures the correct identity of the peer node it is communicating with. Non-repudiation ensures that the originator of a message cannot falsely deny having sent the message. i.e. the assurance that a node cannot later deny the data was sent by it. Node mobility in a MANET poses many security problems and vulnerable to different types of security attacks than conventional wired and wireless networks due to their open medium, dynamic network topology, absence of central administration, distributed cooperation, constrained capability, and lack of clear line of defense. The unconstrained nature of a wireless medium of MANETs allows the attackers for interception, injection, and interference of communication. Without proper security, mobile hosts are easily captured, compromised and hijacked by malicious nodes. Malicious nodes behavior may deliberately disrupt the network so that the whole network will be suffering from packet losses. Damages include leaking secret information, message contamination and node impersonation. Before MANETs are successfully deployed, security issues must be addressed. Usually, cryptographic techniques are used for secure communications in wired and wireless networks. The method of using security solutions of traditional wired networks is not suitable for providing security in MANETs. The main problem of any public-key based security system is to make each users public key available to others in such a way that its authenticity is verifiable. Conventional security solutions to provide public key management is implemented with public key infrastructure (PKI), in which a trusted third party (TTP) holds the public key certificates of all participating entities and acts as an online certification authority (CA) to provide a public key verification service. MANETs do not provide on-line access to trusted authorities or to centralized servers. Implementing public key management and certificate distribution is more challenging due to the problematic key exchange, session handling , absence of any infrastructure and centralized services, frequent node mobility, wireless link instability, possible network partitions, and configuration of all network services on-the-fly. For these reasons, traditional security solutions that require on-line trusted authorities or certificate repositories are not well suited for securing MANETs. Use of public key cryptography and certificates is one of the effective ways of securing a MANET. The main security problems that need to be dealt with in MANETs are: the secure storage of key/data in the devices; the authentication of devices that wish to communicate to each other; the secure key establishment of a session key among authenticated devices; and the secure routing in multi-hop networks [4]. 1.1.5 Security Attacks in MANETs Security means protecting the privacy (confidentiality), availability, integrity and non-repudiation. Security implies the identification of potential attacks, threats and vulnerability of a certain system from unauthorized access, use, modification or destruction. A security attack is any action that compromises or bypasses the security of information illegally or in an unauthorized way. The attack may alter, release, or deny data [10, 11, 14]. The attacks on the MANETs can be broadly classified into two categories: passive attacks and active attacks as shown in Figure 1.2. Both passive and active attacks can be made on any layer of the network protocol stack [3]. Figure 1.2: Types of security attacks Passive Attacks: A passive attack attempts to retrieve valuable information by listening to traffic channel without proper authorization, but does not affect system resources and the normal functioning of the network. Figure 1.3 shows a schematic description of a passive attacker C, eavesdropping on the communication channel between A and B. Figure 1.3: A passive attack The different types of passive attacks are eavesdropping (information leakage), traffic monitoring, and analysis. Passive attacks are very difficult to detect because they do not involve any alteration of the data. The emphasis in dealing with passive attacks is on prevention rather than detection. One of the solutions to the problem is to use powerful encryption mechanism to encrypt the data being transmitted, thereby making it impossible for the attacker to get useful information from the data overheard. Eavesdropping (information leakage) is a very easy passive attack in the radio transmission environment, where malicious nodes capture all traffic, including routing traffic, and thus obtain routing information. When one sends a message over the wireless medium, an attacker equipped with a suitable transceiver in the radio range of the transmission can intercept and capture all traffic including the sensitive routing information. The sender or the intended receiver has no means of detecting if the transmission has been eavesdropping in the radio transmission by the adversary who do not physically connect to the medium. Traffic monitoring collects information of network nodes such as the identities and locations of nodes and the amount of data transmitted among them. Traffic analysis means that a malicious node analyses all captured/received traffic in order to extract information about the characteristics of transmission, such as, which nodes are communicating frequently or exchange huge amounts of data. This information could be exploited to launch further attacks. Active Attacks: An active attack attempts to alter or destroy system resources and the data being exchanged in the network by injecting or modifying arbitrary packets, thus gain authentication and tries to affect or disrupt the normal functioning of the network services. An active attack involves information interruption, modification, or fabrication. Figure 1.4: An active attack As shown in Figure 1.4, an active attacker C can listen, modify, and inject messages into the communication channel between A and B. Active attacks can be either internal or external [5]. External attacks are carried out by nodes that do not belong to the network. These attacks are launched by adversaries who are not initially authorized to participate in the network operations and access the resources without authorization. External attacks usually aim to cause network congestion, denying access to specific network function or to disrupt the whole network operations. Bogus packets injection, denial of service, and impersonation are some of the attacks that are usually initiated by the external attackers. Internal attacks are from compromised nodes that are part of the network. Compared with external attacks, internal attacks are more serious and hard to detect because the attackers know valuable and secret information from compromised or hijacked nodes and possess privileged access rights to the network resources. Active attacks, whether carried out by an external adversary or an internal compromised node, involves actions such as impersonation (masquerading or spoofing), modification, fabrication and replication. The active attacks are classified into different types: MAC Layer attacks, Network Layer attacks, Transportation Layer attacks, Application Layer attacks and Multi Layer attacks as shown in Figure 1.5. MAC Layer Attacks: Jamming Attack In this form of attack, the adversary initially keeps monitoring the wireless medium in order to determine the frequency at which the receiver node is receiving signals from the sender. It then transmits signals on that frequency so that error free reception at the receiver is hindered [3]. Figure 1.5: Classification of security attacks Network Layer Attacks: Wormhole Attack In this attack, two compromised nodes can communicate with each other by a private network connection. A malicious node captures packets from one location in the network and tunnels these packets to the other malicious node at another location. The second malicious node is then expected to replay the tunneled packets locally. The tunnel between two colluding attackers is referred to as a wormhole. The wormhole can drop packets by short-circuiting the normal flow of routing packets or it can selectively forward packets to avoid detection [15, 16, 17]. Black Hole Attack A black hole attack is a kind of denial of service where a malicious node attracts all packets by falsely claiming (advertising) a shortest path to the destination node whose packets it wants to intercept and then absorb them without forwarding to the destination [15]. i.e. a malicious node falsely advertise itself as having the shortest path to the destination node whose packets it wants to intercept causing all nodes around it to route packets towards it. Sinkhole Attack In a sinkhole attack, the adversarys goal is to attract nearly all the traffic from a particular area through a compromised node, creating a metaphorical sinkhole with the adversary at the center. Because nodes on or near the path that packets follow have many opportunities to tamper with application data [18, 19]. One motivation for mounting a sinkhole attack is that it makes selective forwarding trivial by ensuring that all traffic in the targeted area flows through a compromised node, an adversary can selectively suppress or modify packets originating from any node in the area. Gray Hole Attack A gray hole attack is a variation of the black hole attack, where the malicious node is not initially malicious, it turns malicious sometime later. In this attack, an attacker drops all data packets but it lets control messages to route through it [20, 21]. This selective dropping makes gray hole attacks much more difficult to detect than black hole attack. Byzantine Attack In this attack, a compromised intermediate node or a set of compromised intermediate nodes works in collusion and collectively carries out attacks such as creating routing loops, routing packets on non-optimal paths, and selectively dropping packets. Byzantine failures are hard to detect because throughput of attacker nodes as same as other nodes [22]. Information Disclosure Attack In this, a compromised node attempts to reveal confidential or important information regarding the network topology (the structure of the network), geographic locations of nodes, or optimal routes to unauthorized nodes in the network [7][23]. Resource Consumption Attack In this attack, a malicious node deliberately tries to consume/waste away the resources of other nodes present in the network by requesting excessive route discovery (unnecessary route request control messages), very frequent generation of beacon packets, or by forwarding unnecessary packets (stale information) to that node. The resources that are targeted are battery power, bandwidth, and computational power, which are only limitedly available in MANETs [24, 25]. Man-In-The-Middle Attack In this, the attacker exists as a neighbor to any one node in the routing path and alters data that is being transmitted and injects modified packet into network. i.e. a malicious node impersonates the receiver with respect to the sender, and the sender with respect to the receiver, without having either of them realize that they have been attacked with an intension to read or modify the messages between two parties [12]. Neighbor Attack In this attack, upon receiving a packet, an intermediate node records its ID in the packet before forwarding the packet to the next node. An attacker, however, simply forwards the packet without recording its ID in the packet to make two nodes that are not within the communication range of each other believe that they are neighbors (i.e., one-hop away from each other), resulting in a disrupted route. The goal of neighbor attackers is to disrupt multicast routes by making two nodes that are in fact out of each others communication range believe that they can communicate directly with each other [15]. Routing Attacks In this attack, attackers try to alter the routing information and data in the routing control packet. There are several types of routing attacks, such as routing table overflow attack, routing table poisoning attack, packet replication attack, route cache poisoning attack, and rushing attack, mounted on the routing protocol which are aimed at disrupting the operation of the network [3]. Ã ¢-Â ºRouting Table Overflow Attack In this attack, an adversary node advertises routes to non-existing authorized nodes present in the network. The main objective of such an attack is to cause an overflow of the routing tables, which would, in turn, prevent the creation of entries corresponding to new routes to authorized nodes. Proactive routing protocols are more vulnerable to this attack compared to reactive routing protocols. Ã ¢-Â ºRouting Table Poisoning Attack In this attack, a malicious node sends false routing updates to other uncompromised nodes. Such an attack may result in suboptimal routing, network congestion or even make some part of the network inaccessible. Ã ¢-Â ºPacket Replication Attack In this attack, an adversary node replicates stale packets. This consumes additional bandwidth and battery power resources available to the nodes and also causes unnecessary confusion in the routing process. Ã ¢-Â ºRoute Cache Poisoning Attack This attack occurs when nodes are in the updating mode of their tables route. Information stored in the routing tables deleted, changed, and injected with false information. Ã ¢-Â ºRushing Attack In this case, an adversary can rush some routing packets towards the destination, leading to problems with routing. i.e. an adversary node which receives a route request packet from the source node floods the packet quickly throughout the network before other nodes which also receive the same route request packet can react. On demand routing protocols that use route discovery process are vulnerable to this type of attack [26]. Stealth Attacks Stealth attacks are classified into two classes. The first class of attacks attempts to hi-jack or perform traffic analysis on filtered traffic to and from victim nodes. These attacks are mounted, for example, by the modification of routing information. An attacker can divert traffic by using authentic routing messages to fool honest nodes into disrupting their routing tables. The second class partitions the network and reduces good put by disconnecting victim nodes in several ways. For example, the attacker can route a large amount of data through the victim node. This may totally consume the nodes energy resources or create a perception of unavailability due the large quantities of messages being dropped by the victim. Consequently the node under attack will not be used by neighboring routers and becomes isolated. The methods are referred to as stealth attacks since they minimize the cost of launching the attacks and reduce the visibility of the attacker [27]. Transportation Layer Attacks: Session Hijacking Attack Session hijacking is the major transport layer attack. Here, an adversary takes control over a session between two nodes. Since most authentication processes are carried out only at the start of a session, once the session between two nodes gets established, the adversary node masquerades as one of the end nodes of the session and hijacks the session. Session hijacking occurs on two levels: the network level and application level. Application Layer Attacks: Repudiation Attack Repudiation attack is the main application layer level attack. Repudiation refers to the denial or attempted denial by a node involved in a communication of having participated in all or part of the communication [3]. Non-repudiation is one of the important requirements for a security protocol in any communication network and assures that a node cannot later deny the data was sent by it. Multi Layer Attacks: Multi-layer attacks are those that could occur in any layer of the network protocol stack. Denial of service, impersonation or sybil attack, manipulation of network traffic, device tampering, jellifish attack and eclipse attack are some of the common multi-layer attacks. Denial of Service Attack In this attack, an adversary always attempts to prevent legitimate and authorized users of network services from accessing those services, where legitimate traffic cannot reach the target nodes. Denial of Service (DoS) attacks are against CPU power, battery power and transmission bandwidth. A malicious node may launch a DoS attack against another node by requesting routes from that node, or by forwarding unnecessary packets to that node in an attempt to wear down (draining) the other nodes batteries. A DoS attack can be carried out in many ways and against any layer in the network protocol stack, namely, physical layer, link layer, and network layer [4, 12, 31]. Sybil Attack This attack is also known as masquerade or impersonation or spoofing attack. In this attack, a single malicious node attempts to take out the identity of other nodes in the network by advertising false/fake routes. i.e. an attacker pretends to have multiple identities obtained either by impersonating (forges) other nodes or by making use of false identities. It then attempts to send packets over network with identity of other nodes making the destination believe that the packet is from original source [28]. Sybil attacks are classified into three categories: direct/indirect communication, fabricated/stolen identity, and simultaneity. In the direct communication, Sybil nodes communicate directly with legitimate nodes, whereas in the indirect communication, messages sent to Sybil nodes are routed through malicious nodes. An attacker can fabricate a new identity or it can simply steal it after destroying or temporarily disabling the impersonated node. All Sybil identities can participate simultaneously in the network or they may be cycled through [29]. Misrouting Attack This attack is also known as manipulation of network traffic attack. This is a very simple way for a node to disturb the protocol operation by announcing that it has better route than the existing one. In the misrouting attack, a non-legitimate node redirects the routing message and sends data packet to the wrong destination. This type of attack is carried out by modifying metric value of a route or by altering control message fields of a route or modifying the final destination address of the data packet or by forwarding a data packet to the wrong next hop in the route to the destination [30]. Device Tampering Attack (Weak Physical Protection) Unlike nodes in a wired network, nodes in MANETs are usually compact, soft, and hand-held in nature. They could get damaged or lost or stolen easily and misused by an adversary. In military applications, mobile nodes are subject to capturing, compromising and hijacking. In such hostile environments, it is almost impossible to provide perfect physical protection [3]. Jellyfish Attack A jellyfish attacker first needs to intrude into the multicast forwarding group. It then delays data packets unnecessarily for some amount of time before forwarding them. This result in significantly high end-to-end delays and, thus, degrades the performance of real-time applications [31]. Eclipse Attack A pattern of misbehavior called an eclipse attack, which consists of the gradual poisoning of good (uncompromised) nodes routing tables with links to a conspiracy of adversarial nodes (compromised nodes) [12, 15, 18]. 1.1.6 Security Solutions in MANET Various kinds of security attacks are possible on ad hoc routing. Due to inherent characteristics, MANETs are highly susceptible to malicious attacks. To overcome these attacks, available security solutions are used. Attack prevention measures can be used as the first line of defense to reduce the possibilities of attacks. There are two types of security solutions: preventive and detective to overcome these attacks. Preventive solutions are typically based on message encryption techniques, while detective solutions include the application of digital signature and cryptographic hash functions. The prevention schemes proposed for external attacks are key and trust management, whereas the countermeasures for internal attacks are secure routing protocols [5, 7]. 1.2 Motivation of the Work Providing security for MANETs is a difficult problem. The method of using security solutions of a traditional wired network is not suitable. All those methods require online trusted authority. In contrast with conventional networks, MANETs do not provide on-line access to trusted authorities or to centralized servers. For this reason, key management is particularly difficult to implement in such networks. However, key management is deemed as the fundamental essential part of any secure communication. There are two ways to introduce security in MANETs: 1. through a single authority domain, where certification and keys are issued by a single authority, and 2. through full self-organization, where security does not rely on any trusted authority or fixed server. Conventional public key management is implemented with public key infrastructure, in which a trusted third party (TTP) holds the public key certificates of all participating entities and acts as an online

The Catcher In The Rye: Holden :: essays research papers

The Catcher In The Rye: Holden Preface - This book has been steeped in controversy since it was banned in America after it's first publication. John Lennon's assassin, Mark Chapman, asked the former beatle to sign a copy of the book earlier in the morning of the day that he murdered Lennon. Police found the book in his possession upon apprehending the psychologically disturbed Chapman. However, the book itself contains nothing that could be attributed with leading Chapman to act as he did - it could have been any book that he was reading the day he decided to kill John Lennon - and as a result of the fact that it was 'The Catcher In The Rye', a book describing nervous breakdown, media speculated widely about the possible connection. This gave the book even more notoriety. So what is 'The Catcher In The Rye' actually about ? Superficially the story of a young man's expulsion from yet another school, 'The Catcher In The Rye' is in fact a perceptive study of one individual's understanding of his human condition. Holden Caulfield, a teenager growing up in 1950s New York, has been expelled school for poor achievement once again. In an attempt to deal with this he leaves school a few days prior to the end of term, and goes to New York to 'take a vacation' before returning to his parents' inevitable wrath. Told as a monologue, the book describes Holden's thoughts and activities over these few days, during which he describes a developing nervous breakdown, symptomised by his bouts of unexplained depression, impulsive spending and generally odd, erratic behaviour, prior to his eventual nervous collapse. However, during his psychological battle, life continues on around Holden as it always had, with the majority of people ignoring the 'madman stuff' that is happening to him - until it begins to encroach on their well defined social codes. Progressively through the novel we are challenged to think about society's attitude to the human condition - does society have an 'ostrich in the sand' mentality, a deliberate ignorance of the emptiness that can characterize human existence? And if so, when Caulfield begins to probe and investigate his own sense of emptiness and isolation, before finally declaring that the world is full of 'phonies' with each one put out for their own phony gain, is Holden actually the one who is going insane, or is it society which has lost it's mind for failing to see the hopelessness of their own lives? Holden's Personality - There are 3 main aspects in Holden's personality : 1. His criticism toward the 'phony' things in society. The Catcher In The Rye: Holden :: essays research papers The Catcher In The Rye: Holden Preface - This book has been steeped in controversy since it was banned in America after it's first publication. John Lennon's assassin, Mark Chapman, asked the former beatle to sign a copy of the book earlier in the morning of the day that he murdered Lennon. Police found the book in his possession upon apprehending the psychologically disturbed Chapman. However, the book itself contains nothing that could be attributed with leading Chapman to act as he did - it could have been any book that he was reading the day he decided to kill John Lennon - and as a result of the fact that it was 'The Catcher In The Rye', a book describing nervous breakdown, media speculated widely about the possible connection. This gave the book even more notoriety. So what is 'The Catcher In The Rye' actually about ? Superficially the story of a young man's expulsion from yet another school, 'The Catcher In The Rye' is in fact a perceptive study of one individual's understanding of his human condition. Holden Caulfield, a teenager growing up in 1950s New York, has been expelled school for poor achievement once again. In an attempt to deal with this he leaves school a few days prior to the end of term, and goes to New York to 'take a vacation' before returning to his parents' inevitable wrath. Told as a monologue, the book describes Holden's thoughts and activities over these few days, during which he describes a developing nervous breakdown, symptomised by his bouts of unexplained depression, impulsive spending and generally odd, erratic behaviour, prior to his eventual nervous collapse. However, during his psychological battle, life continues on around Holden as it always had, with the majority of people ignoring the 'madman stuff' that is happening to him - until it begins to encroach on their well defined social codes. Progressively through the novel we are challenged to think about society's attitude to the human condition - does society have an 'ostrich in the sand' mentality, a deliberate ignorance of the emptiness that can characterize human existence? And if so, when Caulfield begins to probe and investigate his own sense of emptiness and isolation, before finally declaring that the world is full of 'phonies' with each one put out for their own phony gain, is Holden actually the one who is going insane, or is it society which has lost it's mind for failing to see the hopelessness of their own lives? Holden's Personality - There are 3 main aspects in Holden's personality : 1. His criticism toward the 'phony' things in society.

Answering Question

Psychology in its attempt to establish itself as a scientific study has come up with ingenious ways to be scientific and objective. It was accepted that psychology was concerned with the thoughts, emotions, feelings and the inner processes of the individual, hence to study these aspects; it must develop a method that would dig and explore the said human processes. And the answer was the introspective method. However, as soon as it gained following, it also earned criticisms and lead to another methodological development. The major criticism against the introspective method was its subjectivity and unreliability which basically goes against its being a scientific tool. Conversely, the answer to the introspective method was behaviorism which is completely at odds with it. Behaviorism reduces human behavior into a simple equation wherein a stimulus produces a response and that in order to understand human behavior one must employ the tools of behaviorism. This method appealed to the scientific community as it is measurable, observable and can be replicated. Behaviorism was thought of as a better approach than the introspective method and hence swept it away. The basic aspect that made the introspective method flawed and unscientific is also the same thing that behaviorism neglected to acknowledge and would have enriched this movement more than it is. I believe that people’s introspections are as much as important as the overt behavior of individuals. Psychology is the study of man’s behavior and our behavior cannot be reduced into a simple stimulus is to response theory. Clearly, something happens between the perception of the stimulus and the subsequent reaction to the stimulus. Like for example when my professor told us to work on this assignment, it being the stimulus for sure I and all my classmates will react to it by accomplishing our assigned tasks. However, the bulk of the work happens between the day the tasks were assigned to us and the day we submit our completed papers. Taking it further, when I read the questions of this assignment which happens to be the stimulus, I would naturally begin to draft my answers hence my response to the stimulus. But before coming up with my answers, I have to look inward and ask myself what should be the appropriate answer for this question and how should I present my arguments, in essence I was being introspective. Why we do the things we do can not be fully explained by behaviorism alone. As dynamic human beings with different experiences, we may react to things in the same way but we may have different perceptions or understanding of that stimuli, like when we hear a baby cry, most of us would go and pick the baby to make it stop, but I might do so because the sound of a crying baby is irritating and another person might pick the baby up out of a genuine concern for the baby, hence what goes on inside our mind is much as important in determining how we react to certain things, why we make decisions and pass judgments on others etc. Man is a complex being and the vital aspects that would lead to a better study and understanding of man are found on inner processes that cannot be directly observed and quantified, which is why the mechanistic approach of behaviorism was short-lived. By completely throwing man’s introspections out of the picture, behaviorism threw out what made psychology human. What factors are responsible for the development of modern cognitive psychology? Cognitive psychology is the study of the science of knowing. Its study encompasses the basic thought processes of man and its importance to our daily existence. The modern cognitive psychology movement has been influenced by computer technology. In order to better understand how the brain functions and how it controls everything that we do, we must first study it, but since it is ethically impossible to take a healthy person’s brain and study it, we must find a similar model, and this is where the idea that the computer is much alike the brain. With its immense computing power, the computer have been developed to simulate human intelligence and allowed a new way of studying how the brain stores, records, and processes information. Moreover, the brain as the single controlling processing unit in man, it is responsible for all of our bodily actions thus recent developments in imaging have given psychologists the opportunity to study what part of the brain is responsible for what action and how bizarre diseases can be explained by a dysfunction in the brain like the Capgras syndrome. Write a 200-300 word summary and critical analysis of this article. Discuss what the article is basically about, its strong and weak points, how convincing (or unconvincing) you find its arguments, and how it might be followed up (e.g., if you think the article suggests any promising, new ideas for future research, describe what they are and how they might best pursued.) The article attempts to discuss how cognitive psychology developed. Kedler proposes that cognitive psychology was not born rather it slowly came into being. The author then presents the influences that contributed to the development of cognitive psychology in history. He says that due to the curious mix of theoretical approaches in cognitive psychology it is not a singularly minded discipline like structuralism or Gestalt psychology. Moreover, the author claims that because of the complexity in the theories within cognitive psychology and the different areas of study within the discipline have made it more computer science than psychology. The strengths of this article are found on its exhaustive presentation of the different theoretical influences in the field of psychology, from Wund’s introspectionism, Piaget’s cognitive development, Tolman’s cognitive map, and a host of other theories that he categorizes as a study of cognition. He also gave emphasis on how the fields of communications engineering, computer science, linguistics and human engineering as the mover in the field of cognitive psychology in terms of new researches and areas of discourse. The weakness of this article is in the fact that it was not able to prove how cognitive psychology came into being. The author only enumerated and discussed the numerous theories that had to do with cognition, memory and learning. What he presented were the natural consequences of the theories and a novel explanation of how this theories influenced cognitive psychology is not reiterated, its as if the reader is left to deduce how that came about. The article is convincing in terms of how cognitive psychology is made up of a number of schools of thought and but it is unconvincing when it says that cognitive psychology is more of a computer science than psychology, when clearly it is within the realms of psychology based on the processes involved in learning, memory, and processing. At the same way, human engineering, communications engineering, linguistics and computer science are based on psychological processes and use constructs that have been studied and explored by psychology first. References Kendler, H. (1987) Cognitive Psychology in Richard P. Honeck, Introductory Readings for Cognitive Psychology 3rd ed   p.6-13 (1997), William C. Brown Communications Reisberg, D. (2001). Cognition: Exploring the Science of the Mind   2nd edition. New York: WW Norton 2001                                       

Prose Appreciation

The East, an excerpt from the short story â€Å"Youth† written by Joseph Conrad is a descriptive paragraph about a young mans first impression of the east. The tone of the excerpt is admiring because the writer uses words such as â€Å"impalpable† and â€Å"enslaving† suggesting that the young deckhand was overwhelmed by the magnificent sight of the east. The aim in descriptive paragraphs is to build descriptive detail. The writer mostly uses long sentences which are suitable for a descriptive paragraph because there can be a lot of detail packed into long sentences. However, there are two short sentences. The fragment sentence â€Å"And this is how I see the east† is used to create suspense while the short sentence near the end of the excerpt â€Å"That I can never forget† emphasis just how great an impression the east made on the narrator. While most of the sentences are assertive sentences, used to experience the scene of the east through the eyes of the narrator as he approaches the bay, most sentences are also loose sentences to accumulate descriptive detail. However, in the excerpt there are some unordinary sentences. The opening sentence â€Å"And this is how I see the east† is a periodic sentence and the delay of the verb â€Å"see† is used to create suspense, on the other hand, to emphasize the immense size of the bay, the writer uses the parallel sentence â€Å"I see a bay, a wide bay†. We see the same affect on â€Å"wide† in the parallel sentence as we saw on â€Å"See† is the periodic sentence. Through out the excerpt, many different types of language devices are used. Sight imagery: used to implant the image of the mountains and the bay the narrator is seeing into the readers mind, Tactile imagery: to give the sensation of holding an oar in hands, Olfactory imagery: to make the reader experience the smells of the wind as the narrator did, Similes: â€Å"I see a bay, a wide bay, smooth as glass and polished like ice† to explain just how perfect a day is was and how calm the sea was, and â€Å"It was impalpable and enslaving, like a charm, like a whispered promise of mysterious delight† used to create the sense of power that the east had over the young man, Personification: the narrator has â€Å"looked into the east’s very soul† used to show the connection between the narrator and the east. The excerpt clearly demonstrates how dumbfounded and impressed the narrator was with the east during his first impression.