Smart socket Essay Example

Smart socket Essay Although ad-hoc solutions exist for some of these problems, it is usually up to the applications user to discover the cause of the connectivity problems and find a solution. In this paper we describe Smokestacks, a communication library that lifts this burden by automatically discovering the connectivity problems and solving them with as little support from the user as possible. Categories and Subject Descriptors: C. 2. 4 [Distributed Systems]: Distributed applications General Terms: Algorithms, Design, Reliability Keywords: Connectivity Problems, Grids, Networking, Parallel Applications 1 . Parallel applications are increasingly run in Grid environments. Unfortunately, on many Grid sites the ability of machines to create or accept network connections is severely limited by network address translation (NAT) [14, 26] or firewalls [15]. There are even sites that completely disallow any direct communication between the compute nodes and the rest of the world (e. G. , the French Grinding system [3]). In addition, multi homing (machines with multiple network addresses) can further complicate connection setup. We will write a custom essay sample on Smart socket specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Smart socket specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Smart socket specifically for you FOR ONLY $16.38 $13.9/page Hire Writer For parallel applications that require direct communication between their components, these limitations have hampered the transition from traditional multi receptors or cluster systems to Grids. When a combination of Grid sites is used, serious connectivity problems are often encountered. Smokestacks is part of the Ibis project, and can be found at http://www. CSS. Vi. Ml/ibis Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or the full citation on the first page. Many problems, however, can only be solved by adapting the application or the communication library it uses. To make matters worse, as soon as the set of Grid systems being used changes, large part of this process needs to be repeated. As a result, running a parallel application on multiple Grid sites can be a strenuous task [34]. In this paper we will describe a solution to this problem: the Smokestacks communication library. The primary focus of Smokestacks is on ease of use. It automatically discovers a wide range of connectivity problems and attempts to solve them with little or no support from the user. Smokestacks combines many known solutions, such as port forwarding, TCP splicing and SSH tunneling, and introduces several new ones that resolve problems with multi homing and machine identification. In 30 connection setup experiments, using 6 different sites worldwide, Smokestacks was always able to establish a connection, while conventional sockets only worked in 6 experiments. Using heuristics and caching, Smokestacks is able to significantly improve the connection setup performance. Smokestacks offers a single integrated solution that hides the complexity of connection setup in Grids behind a simple interface that closely resembles sockets. We will show that it is relatively straightforward to port an existing application to Smokestacks, provided that certain programming guidelines are followed. Smokestacks is not specifically intended for use in parallel applications or Grids. It can also be applied to other distributed applications, such as visualization, cooperative environments, or even consumer applications such as instant messaging, file sharing, or online gaming. However, many of these applications only require a very limited degree of connectivity. Often, clients simply connect to a server in a well-known location, making it relatively easy to apply an ad-hoc solution when a connectivity problem occurs. Parallel applications, however, can be much more challenging. They often require a large number of connections between the participating machines, and each machine must such applications in a Grid environment with limited connectivity is difficult. Therefore, this paper will focus on this domain. N Section 2 we describe the connectivity related problems encountered while running applications on multiple Grid sites. Section 3 describes how these problems are solved in Smokestacks and briefly looks at the programming interface. Section 4 evaluates the performance of Smokestacks, Section 5 describes related work, and Section 6 concludes. 2. CONNECTIVITY PROBLEMS In this section we will give a description of the network related problems that can occur when running a single parallel or distributed application on multiple Grid sites. . 1 Firewalls As described in [1 5], A firewall is an agent which screens network traffic in some way, blocking traffic it believes to be inappropriate, dangerous, or both. . Many sites use firewalls to protect their network from unauthorized access. Firewalls usually allow outbound connections, but block incoming connections, often with the exception of a few welkin ports (e. G. , port 22 for SSH). It is obvious that this inactivity restriction can cause severe problems when running a parallel application on multiple sites. When only a single participating site uses firewall, the connectivity problems can sometimes be solved by ensuring that the connections setups are in the right direction, I. E. , that all required connections between open and firewall machines are initiated at the firewall site. This solution may require changes to the applications or communication libraries, however. Also, if both sites use a firewall, this approach can no longer be used. In this case, a firewall will always be encountered regardless of he connection setup direction. One way to solve the problems is to request an open port range in the firewall. Connectivity can then be restored by adapting the application to only use ports in this range. Besides requiring reconfiguration of the firewall, open ports are also seen as a threat to site security. When both machines are behind a firewall it may still be possible to establish a direct connection using a mechanism called TCP splicing [6, 10, 13, 20]. Simply put, this mechanism works by simultaneously performing a connection setup from both sides. Since this approach requires explicit cooperation teens the machines, some alternative communication channel must be available. . 2 Network Address Translation As described in [21], Network Address Translation is a method by which IP addresses are mapped from one address realm to another, providing transparent routing to end hosts. . NAT was introduced in [12] as a temporary solution to the problem of IPPP address depletion. Although the intended solution for this problem, IPPP, has been available for some time, NAT is still widely used to day. Frequently used [21, 29]. This type of NAT allows outbound connections from sites using riveter addresses, but does not allow incoming connections. Both the IP address (and related fields) and the transport identifier (e. G. , TCP and JODI port numbers) of packets are translated, thereby preventing port number collisions when a set of hosts share a single external address. As mentioned above, NAT only allows outbound network connections. Incoming connections are rejected, since the connection request does not contain enough information to find the destination machine (I. E. , only the external IP address is provided, but that may be shared by many machines). This restriction leads to connectivity problems hat are very similar to those caused by firewalls. Therefore, the solution described in Section 2. 1 (connecting in the right direction) also applies too NAT setup, and fails in a similar way when multiple NAT sites try to interconnect. Although the TCP splicing mechanism can also be used to connect two NAT sites, a more complex algorithm is required to compensate for the port translation performed by NAT [6, 20]. Some NAT implementations have support for port forwarding, where all incoming connections on a certain port can be automatically forwarded to a certain host inside the NAT site. Using mechanisms such as Upon [5], DIF [28], or MEDICO [30], applications can contact the NAT implementation and change the port forwarding rules on demand. Port forwarding lifts many of the restrictions on incoming connections. Unfortunately, Upon is mostly found in consumer devices, MEDICO is still under development, and DIF only supports NAT (and firewall) implementations based on Interfile [1]. As a result, these mechanisms are not (yet) generally usable in Grid applications. Currently, Smokestacks only supports Upon. In addition to causing connection setup problems, NAT also complicates machine identification. Machines in a NAT tit generally use IP addresses in the private range [26]. These addresses are only usable within a local network and are not globally unique. Unfortunately, parallel applications often use a machines IP address to create a unique identifier for that machine. When multiple NAT sites participate in a single parallel run, however, this approach can not be used, since the machine addresses are no longer guaranteed to be unique. 2. 3 Non-routed networks On some sites no direct communication between the compute nodes and the outside world is possible due to a strict separation between the internal and external networks. No aching is accessible, and the connectivity of this machine may be limited by a firewall or NAT. Two of the sites used in Section 4 use such a setup. It is clear that this is a major limitation when the site is used in a parallel application. The only possibility for the compute nodes to communicate with other sites is to use front-end machine as a bridge to the outside world, using, for example, an SSH tunnel or a SOCKS [24] proxy. These are non-trivial to set up, however. 2. 4 Multi Homing When multi-homed machines (I. E. , machines with multiple network addresses) participate in a parallel application, another interesting problem occurs. When creating a connection to such a machine, a choice must be made on which of the possible target addresses to use. The outcome of this choice may depend on the location of the machine that initiates the connection. For example, the front-end machine of a site has two addresses, a public one, reachable over the internet, and a private one used to communicate with the sites compute nodes. As a result, a different address must be used to reach teachings depending on whether the connection originates inside or outside of the site. In [34] we called this the Reverse Routing Problem. Normally, when a multi-homed machine is trying to connect to a single IP address, a routing table on the machine decides which network is used for the outgoing connection. In the example described above the reverse problem is encountered. Instead of having to decide how to exit a multi-homed machine, we must decide on how to enter it. This problem is non-trivial, since the source machine generally does not have enough information available to select the correct target address. As a result, several connection attempts to different addresses of the target may be necessary before a connection can be established. In Section 3. 2 we will describe heuristics that can be used to speed up this process. Multi homing can have a major effect on the implementation of parallel programming libraries. The example above shows that it is not sufficient to use a single address to represent a multi-homed machine. Instead, all addresses must be made available to the other participants of the parallel application. In addition, some of the addresses may be in a private range and refer to a different machine when used in a different site. Therefore, it is also essential to check if a connection was established to the correct machine. 3. SMOKESTACKS In this section we will give an overview of the design, implementation and programming interface of the Smokestacks library, and describe how it solves the problems described in the previous section. 3. 1 Overview Currently, Smokestacks offers four different connection setup mechanisms, Direct, Reverse, Splicing, and Routed. An overview of how these mechanisms solve the connectivity problems described in Section 2. As the table shows, each problem is solved by at least one mechanism. Table 1 : Overview of connectivity problems and their solutions. Connection Setup Mechanism Problems Direct Reverse Splicing Routed Identification X Multi Homing X Single FEW/NAT pox xx Dual MINOT (X) XX No Routing X The machine identification and multi-homing problems are solved by the direct connection setup. As will be explained below, this approach also has limited firewall traversal capabilities (using SSH tunneling), so in certain situations it may succeed in establishing a connection in a single or even a dual firewall setting. In the table these entries are shown between brackets. A reverse connection setup is only capable of creating a connection when a single firewall or NAT limits the connectivity. Splicing is capable of middling both single and dual firewall/NAT configurations. However, this approach is significantly more complex than a reverse connection setup (especially with dual NAT) and may not always succeed. Therefore, reverse connection setup is preferred for single firewall/NAT configurations. A routed connection setup can be used in any situation where the connectivity is limited. Unlike the previous two approaches it does not result in a direct connection. Instead all network traffic is routed via external processes called hubs (explained in Section 3. 3), which may degrade both latency and throughput of the connection. Therefore, the previous mechanisms are preferred. When connecting to or from a machine on a non-routed network, however, a routed connection is the only choice. The Smokestacks implementation is divided into two layers, a low-level Direct Connection Layer, responsible for all actions that can be initiated on a single machine, and a high-level Virtual Connection Layer that uses side-channel communication to implement actions that require cooperation of multiple machines. The direct connection layer is implemented using the standard socket library. The virtual connection layer is implemented using the direct connection layer. Both layers will be explained in more detail below. Currently, Smokestacks is implemented using Java [2]. 3. 2 Direct Connection Layer do not require explicit cooperation between machines, such as determining the local addresses or creating a direct connection. It also supports a limited form of SSH tunneling. 3. 2. 1 Machine Identification During initialization, the direct connection layer starts by scanning all available network interfaces to determine which IP addresses are available to the machine. It then generates a unique machine identifier that contains these addresses, and that can be used to contact the machine. This identifier will automatically be unique if it contains at least one public address. If all addresses are private, however, additional work must be done. A machine that only has private addresses is either in a NAT site or uses a non-routed network. In the first case, a unique identifier can still be generated for the machine by acquiring the external address of the NAT. Provided that this address is public, the combination of external and machine addresses should also be unique, since other machines in the same NAT site should have a different set of private addresses, and all other NAT sites should have different external address. The Smokestacks library will use Upon to discover the external address of the NAT site. If this discovery fails, or if the returned address is not public, a Universally Unique Identifier (JUDI) [23], will be generated and included in the machine identifier, thereby making it unique. 3. 2. 2 Connection Setup Once initialized, the direct connection layer can be used to set up connections to other machines. The identifier of the target machine may contain multiple network addresses, some of which may not be reachable from the current location. The private dresses in the identifier may even refer to a completely different machine, so it is important that the identity of the machine is checked during connection setup. As a result, several connection attempts may be necessary before the correct connection can be established. When multiple target addresses are available, a choice must be made in which order the connection attempts will be performed. Although simply using the addresses in an arbitrary order should always result in a connection (pro-vided that a direct connection is possible), this may not be the most efficient approach. Many Grid sites offer historiographer networks such as Merriment [7] or Infinite [4] in addition to a regular Ethernet network. Using such a network for inter-site communication may significantly improve the applications performance. In general, these fast networks are not routed and use addresses in the private range, while the regular Ethernet networks (often) use public addresses. Therefore, by sorting the target addresses and trying all private ones first, the fast local networks will automatically be selected in sites with such a setup. The drawback of if the connection originates on a different site. This may cause a significant overhead. Therefore, Smokestacks uses a heuristic that sorts the target addresses in relation to the addresses that are available locally. For example, if only a public address is available on the local machine, it is unlikely that it will be able to create a direct connection to a private address of a target. As a result, the connection order public before private is used. This order is also used if both machines have public and private addresses, but the private addresses refer to a different network (e. G. , 10. 0. 0. 10 vs 192. 168. 1. 20). The order private before public is only used if both machines have private addresses in the same range. Section 4 will illustrate the performance benefits of this heuristic. Unfortunately, it is impossible to make a distinction between addresses of the same class. For example, if a target has multiple private addresses, we can not automatically determine which address is best. Therefore, if a certain network is preferred, the user must specify this explicitly. Without this explicit configuration, Smokestacks will still create a direct connection (if possible), and the parallel application will run, but its performance may be suboptimal. When a connection has been established, an identity check s performed to ensure that the correct machine has been reached. This would be a simple comparison if the complete identifier of the target is available, but unfortunately this is not always the case. User provided addresses are often used to bootstrap a parallel application. These addresses are often limited to a single hosannas or IP address, which may only be part of the addresses available to the target machine. Therefore, the identity check used by Smokestacks also allows the use of partial identifiers. Whenever a connection is created, the target machine provides its complete identity o the machine initiating the connection. This machine then checks if both the public and private addresses in the partial identity are a subset of the ones in the complete identity. If so, the partial identity is accepted as a subset of the complete identity, and the connection is established. Note that although the connection is created to a machine that matches the address specified by the user, it is not necessarily the correct machine from the viewpoint of the parallel application. Unfortunately, in such cases it is up to the user to provide an address that contains enough information to reach the correct machine. . 2. 3 Open Port Ranges and Port Forwarding When a firewall has an open port range available, Smokestacks can ensure that all sockets used for incoming connections are bound to a port in this range. There is no way of discovering this range automatically, however, so it must be specified explicitly by the user. In addition, Smokestacks can use the Upon protocol to configure a NAT to do port forwarding, I. E. Automatically forward all incoming connections on a certain external port to a specified internal address. However, as explained before, this protocol is mainly used in consumer devices. In addition to regular network connections, the direct connection layer also has limited support for SSH tunneling. This feature is useful for connecting to machines behind a firewall that allows SSH connections to pass through. It does, however, require a suitabl e SSH setup (I. E. , public key authentication must be enabled). Creating an SSH tunnel is similar to a regular connection setup. The target addresses are sorted and tried consecutively. Instead of using the port specified in the connection setup, however, the default SSH port (I. E. , 22) is used. When a connection is established and the authentication is successful, the receiving SSH daemon is instructed to forward all traffic to the original destination port on the same machine. If this succeeds, the regular identity check will be performed to ensure that the right machine has been reached. Although this approach is useful, it can only be used to set up a tunnel to a different process on the target machine. Using this approach to forward traffic to different machines requires extra information. For example, setting up an SSH tunnel to a compute node of a site through the sites fronted, can only be done if it is clear that the fronted must be contacted in order to reach the target machine. Although this approach is used in some projects [8], the necessary information cannot be obtained automatically and must be provided by the user. Therefore, Smokestacks uses a different approach which will be described in detail in Section 3. 3. 3. 2. Limitations The direct connection layer offers several types of connection setup which have in common that they can be initiated by a single machine. No explicit cooperation between machines is necessary to establish the connection. There are many cases, however, where connectivity is too limited and the direct connection layer cannot be used. In general, direct connections to sites that use NAT or a firewall are not possible. Although SSH tunneling and o pen port ranges alleviate the firewall problems, they require a suitable SSH setup or extra information from the user. Port forwarding reduces the problems with NAT, but is rarely supported in Grid systems. Therefore, these features are of limited use. In the next section we will give a detailed description of the virtual connection layer, which solves these problems. 3. 3 Virtual Connection Layer Like the direct connection layer, the virtual connection layer implements several types of connection setup. It offers a simple, socket-like API and has a modular design, making it easy to extend. Besides a direct module that uses the direct connection layer described above, it contains several modules that offer more advanced types of connection setup. These modules have in common that they cooperation (and thus communication) between the source and target machines in order to establish a connection. As a result, side-channel communication is required to implement these modules. 3. 3. 1 Side-Channel Communication In Smokestacks, side-channel communication is implemented by creating a network f interconnected processes called hubs. These hubs are typically started on the fronted machines of each participating site, so their number is usually small. When a hub is started, the location of one or more other hubs must be provided. Each hub will attempt to setup a connection to the others using the direct connection layer. Although many of these connections may fail to be established, this is not a problem as long as a spanning tree is created that connects all hubs. The hubs use a gossiping protocol to exchange information about themselves and the hubs they know, with the hubs that they are connected to. This way information about each hub quickly spreads to all hubs in the network. Whenever a hub receives information about a hub it has not seen before, it will attempt to set up a connection to this hub. This way, new connections will be discovered automatically. All gossiped information contains a state number indicating the state of the originating machine when the information was sent. Since information from a hub may reach another hub through multiple paths, the state number allows the receiver to decide which information is most recent. By recording the length of the path traversed thus far in he gossiped information, hubs can determine the distance to the sites that they can not reach directly. Whenever a hub receives a piece of information about another hub containing a shorter distance than it has seen so far, it will remember both the distance and the hub from which the information was obtained. This way, we automatically create a distributed routing table with the shortest paths between each pair of hubs. This table is later used to forward application information (as will be described below). When an application is started, the virtual layer on each machine creates a single connection to the hub local to its tit. The location of this hub can either be explicitly species- fled or discovered automatically using JODI multicast. 3. 3. 2 Virtual Addresses The connection to the hub can now be used as a side channel to forward requests to otherwise unreachable machines. To ensure that the target machines can be found, addresses are used, consisting of the machine identifier (see Section 3. 2), a port number, and the identifier of the hub the machine is connected to. All requests for the target machine can then be sent to the local hub, which forwards it in the direction of the target

Juche essays

Juche essays Comrade Kim Il Sung was a member of the Presidium of the Political Bureau, Secretary of the Central Committee of the Workers' Party, and a member of the Party Central Military Commission. He had created the Juche (defined as self-reliance) idea in the 1950s for the purpose of cutting off Soviet Union influence, and a way purge political opponents (The People's Korea). He emphasized that it was "the idea that the masters of the revolution are the most popular masses and that the masses are the motive force of the revolution" (Hookon, 95). In other words, it was the idea that one is the master of his/her own destiny. At that time, the "de-Stalinization" movements were occurring in the Soviet Union after the death of Stalin, who had helped Kim Il Sung achieve power. In addition, due to the failure of the Korean War, criticism against Kim Il Sung was also on the rise. He used the notion of Juche Ideology to support political campaigns "designed to prevent the influence of the "de-Stal inization" movement from infiltrating into North Korea," and to motivate the people to adapt the spirit of self-reliance in coping with the economic difficulties (Hun, 45). North Korea asserts that the Juche Ideology is a creative adaptation of Marxism-Leninism to the conditions of North Korean society. Juche embraces philosophical, socio-historical, and guiding principals: The philosophical principals explains that a man is the master of everything, of the world and his own destiny. He also decides everything, meaning that he plays a decisive role in changing the world and in shaping his own destiny. The socio-historical principal represents a new view of social history. It explains that the popular masses are the subject of social history. This history of human society is the history of the struggle to realize and defend the Chajusong (independence) of the popular masses (TMCCWPK). The socio-historical movement was a movement of the popul...

The Regions of Europe Research Paper Example | Topics and Well Written Essays - 2500 words

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In contrast, the second group provides accurate parts and important programmes such as flash-memory and DRAM. This group is strong because of their specialized and advanced products, as well as the lack of alternative products (Nistor, 2010). There are some suppliers who dominate the market; for example, Intel, Microsoft and Sony. So, it is important for Apple to have a good relationship with its suppliers. Power of the buyer The buyers bargaining power is very high in the industry because competitors offer a wide range of similar products with competitive prices. The Apple Corporation faces a moderate threat from buyers because they have a lot of products that consumers can choose from. In addition, the threat of buyers comes from their demand for new features in Apple products. However, there are a large number of companies that offer similar products and there is quite a big differentiation in price and performance. Therefore, loyalty is often shown towards a specific brand because there are not many differences in the quality and price between brands (Nistor, 2010). Buyers are often more sensitive to brand rather than price. Apples customers are individuals, education departments, enterprises, governments and creative customers. So, the variety of consumers and their needs has a direct impact on Apples future strategies. Threat of substitutes The technological environment is changing fast every day. There are not many substitutes in this industry because of the high-tech features. However, alternatives are always available from competitors. If some other company such as BlackBerry, Google, Samsung or Microsoft come up with new technology or the same kind of phone at a lower price or with more features at the same price, then this is a problem for Apple (O Grady, 2009). Customers usually tend to look to the latest technology instead of traditional methods. Apple has the ability and efficiently to design and develop its own hardware and application software to become unique and distinct from its competitors. Competitive rivalry The competition in this industry is very high, almost in all areas of business, because of the continuing requirement to provide new products all the time. Competitive prices, new products, design innovations and technology are the main factors that Apple has to compete with other international companies on, such as IBM, HP, Acer and Dell. The consumers choices also differ; some prefer to save some cash rather purchase high performance specification technology and some prefer the newest technology. So, the result is that companies implement different strategies; for example, low-cost and best-cost strategies. Some manufacturers offer products at the lowest price in an attempt to cut their costs by ignoring everything except some basic features. Some other companies in the middle price range, such as Dell and HP, focus on attracting customers by offering varying prices. And the top of the range companies, like Apple, gain customers through their high quality products, features and inn ovative design, which makes their products popular all over the world (O Grady, 2009). APPENDICES: Porters Generic Strategy model: Porters Five Forces model:

Term Essays -- essays research papers

Dreams   Ã‚  Ã‚  Ã‚  Ã‚   Every ninety minutes of every night we’re asleep, a dream unfolds. The short dreams at the beginning of the night are usually no more exciting that the idle thoughts that randomly pop into our heads when we’re awake. But as the night progresses, the length of each dream increases (the last dream can be up to twenty minutes long), the body responds more intensely (increased heartbeat, respiration, muscle twitching), and the dreams become deeper.   Ã‚  Ã‚  Ã‚  Ã‚  Dreams are sometimes said to be ordinary sequences of images that are experienced by the mind during sleep. For thousands of years they were regarded as divine visitations or predictions. Dreams were not really scientifically studied until the 19th century. Today they are still being studied to learn more about man’s nature. Dreaming is a natural ability- we all dream every night. Every one dreams when sleeping at least three to four times every night. The problem however is remembering the dream. But there is a way to remembering dreams. It is believed that dreams are remembered more accurately immediately after awakening during the night rather than in the morning. Remembering dreams takes time, effort, and patience. Researchers discovered that people who tend to forget their dreams show a greater amount of rapid eye movement, which is associated with greater amounts of activity in the dream. However, when these people did remember the content of their dreams, it wa...

The Role of Women in Perfume and the Assault

The Role of Women in Perfume and The Assault In most cases, women are portrayed either as mother, lovers or people that fulfill men’s sexual needs. Both Perfume by Patrick Suskind and The Assault by Harry Mulisch is no exception. However, the reader might notice that in both novels women are portrayed in a flat, two-dimensional way and yet, paradoxically, have a significant symbolic value. The women of these novels seem to project the protagonists’ needs for these kinds of love and without them the novel would not exist. Therefore, they are not important for who they are, but rather for what they represent- the maternal and sexual love for men. In The Assault, Anton’s mother barely appears in the novel and yet we can notice how her subtly strong character had left a mark on Anton’s life. Her importance lays in what she represents in his childhood memory- a strong woman who is the core of the family. â€Å" †¦ She had a cavity in her tooth that could not be treated just then; to relieve the pain she had found a leftover clove in the kitchen to put on the sore spot, just as her mother and grandmother used to do. She sat up straight, but her husband across the table was bent over, reading a book. † (Mulish,10) Though this is a little detail that Mulisch had added, it characterizes her by inferring that she was strong. A contributing factor could be the setting of the novel. They were in time of war and the circumstances force her to be strong. We can also see a contrast between the mother and the father, the father was bending while she was sitting straight up. This infers that she was the more dominant figure. Therefore, even though Anton had lost both parents. The reader notices that Anton later on seeks Truus and Saskia to replace her, but does not search for anyone to replace his father. Truus who is also barely appears in the novel is a proof of how Anton never fully recovered of losing his mother. She was present in a time where he needed her affection. However, she is like a bridge to Anton between maternal and sexual love. â€Å"He touched her fingers; she took hold of his hand and pulled him close. On the cot she embraced him with one arm and with her other hand pressed his head against her breast. She smelled of sweat but also of something sweetish that he couldn’t identify. Perhaps it was perfume. † (Mulish, 32). Though she represents security and love like his mother did to him. The word choice by Mulisch insinuates Anton’s sexual awakening. The fact that they are on a ‘cot’ or a bed highlights the intimacy. She embraced him like a mother would embrace her child, however the focus on her ‘breasts’ arouses sexual feelings in Anton which he will realize later on in his life. Moreover, in the absence of light and presence of complete darkness, Anton cannot use his sight that is where the tactile and olfactory sense becomes heightened. This causes the scene to be more intense in the reader’s head. Saskia who is Anton’s first wife is also a two dimensional character in the book that is only present as Anton’s image of Truss. When Anton grows up he realizes that Truus was more than a mother figure to him. â€Å"There was nothing wrong with Saskia’s looking like the idea of Truus. Truus had under these circumstances, aroused an image in his mind to which Saskia seemed to respond, and that was fine, for it was not Truus’s image, but his own, and where it came from was unimportant†¦Ã¢â‚¬  (Mulish, 131) The use of the word ‘aroused’ has a sexual connotation which came from the fact he felt intimacy in the dark and as a young boy, though unconsciously this intimacy aroused something inside him. Truus became like a fantasy of love that he perused. Saskia represents that love that he needed. Moreover, the addition of ‘under the circumstances’ insinuates that at the previous moment Anton needed certain affection which was in a form of a mother. However, now he needs it in a non-platonic form. This is where it shows that Anton never wholly recovered from losing his mother. As Sigmund Freud’s theory suggests, a man unconsciously marries a mother figure. Therefore, since Truus seemed to represent a mother figure and Saskia is his image of Truus, the mother figure in this novel is linked with romantic interest. Due to all the events that had happened to Anton, the woman he encounters in the dark (Truus) embodies his need for courageous, maternal and erotic love. This makes the two dimensional character Saskia, a symbol for his erotic desire. Anton in this passage is trying to reassure himself that where Saskia’s image came from is ‘unimportant’, however later on the readers realize that it actually does matter to him as they get divorced. Similarly to The Assault, the women in Perfume are portrayed very superficially and like Sasika, they represent erotic love. Although Grenouille seems uninterested in sex, there are many sexual parallels. In passages where Grenouille smells the women, Suskind describes it very sexually. â€Å"†¦ he (Grenouille) tore off her dress, and the stream of scent became a flood that inundated him its fragrance. He thrust his face to her skin and wept his flared nostrils across her, from belly to breast, to neck, over her face and hair.. †¦ down her genitals, to her thighs and white legs. † (Suskind, 45). Suskind uses imagery to form an image the reader’s mind. Like Mulisch did in the scene where Anton meets Truus, Suskind highlights the olfactory sense rather than others. This makes us smell the women and almost feel Grenouille’s sensation. He describes the power of the scent as a flood of water that moves towards Grenouille and floods him. He is completely taken over by it as if it were sexual feelings. However, he has no interest in the girl herself, but rather what she possesses. Here is where he parallels to Anton, who is not interested in whom Truus was but in what she represents to him. Stripping the females from their scent degrades them and reveals how Grenouille, like Anton, extracts what he needs of the woman and forgets about her as a whole. The remains of the females, which are their individualities, are forgotten like dead flower petals. â€Å"They lay on the surface for a moment, like eyes facing instant death, and lost all the color the moment the spatula pushed them down into the warm, oily embrace. †¦And it was not that the dead blossoms continued to give off scent there in the oil – no, the oil itself had appropriated the scent of the blossoms. † (Suskind, 181). This is the processes that Grenouille uses to steal scents from girls. Therefore, the blossoms here are a metaphor for the girls. This insinuates that they are only important for their scent which pleases Grenouille. The rest of the girl, which is her personality and her individuality all lies insignificantly on the surface ‘like eyes facing instant death’. Suskind continues to say how the blossoms had lost their color the moment Grenouille pushed the spatula. Sine color is what makes them beautiful it is insinuated that when Grenouille steals their scents, they are no longer beautiful for their inner selves. This makes Grenouille selfish. Anton and him extract what they need from the women and forget about her a whole. They do this to replace love that they were deprived of in their childhood. Like Anton Grenouille is deprived of his mother’s love and losing her has had a crucial impact on him. Since there is a thin line between different kinds of love, Grenouille, who is missing maternal love projects his needs in a sexual way. HE steals the essence of women for his own personal pleasure. â€Å"They lay on the surface for a moment, like eyes facing instant death, and lost all the color the moment the spatula pushed them down into the warm, oily embrace. And it was not that the dead blossoms continued to give off scent there in the oil – no, the oil itself had appropriated the scent of the blossoms. †(Suskind, 181) The use of specific time emphasizes the extent of Grenouille’s love- with the scent. Smell is always a strong sense that people associate with people they care for. It is intimate. Therefore it seems like non-platonic love. Moreover, the fact that Suskind writ es that Grenouille is not in love with the girl, but the scent emphasizes how Grenouille, like Anton uses women to project his needs. In conclusion, both Mulisch and Suskind do not show any effort in making the reader know the female characters deeply. Some women even remain unnamed for the whole novel! However, their presence is extremely crucial for the protagonists. Women are a projection of men’s needs. Some people may be offended when noticing such aspects of the portrayal of women in these two novels. There are two interpretations to why the authors portrayed the women that way. They could be either critiquing society for objectifying women or this portrayal reflects the authors’ own opinions

Enola Gay Display at the Smithsonian essays

Enola Gay Display at the Smithsonian essays America is in the midst of a culture war, and one of the latest skirmishes occurred between the houses and hedgerows surrounding the Smithsonian Museum. On one side were the members of a growing numbers of acedemians and cultural theorists who believe that American should not be honored as a country which has been a continued source of peace, and leadership in the world. History should be taught in a context, and that context needs to challenge individuals to think on a larger social scale of how our actions may adversely affect others. The opposing forces are those who have fought, and sometimes given the ultimate sacrifice to earn the countries place of responsibility as the leader of the free world, and only remaining superpower. These men and women look back at America's actions and remember the issues and limitations of the day. This group has a living memory of historical events, and is opposed to reinterpreting them in light of 21st century political cynicism, or academic enlighten. One group believes that if the military forces were downsized, and moneys spent on nation building and international charity projects, that the world would become a safer, more peaceful place. The other legion understands that some men and organizations in the world have set their desires on dominating others and loose no sleep at night over trampling civil and human rights in order to gain their objectives. This group understands that a strong military, as well as a will to use it, is an important building block which has created the peace and prosperity which America and the entire world now enjoy. This cultural war cannot always be identified in terms of liberal or conservative, because individuals from either group may launch salvos from either front. The war cannot be called one of educated vs. uneducated or public sector politicians vs. private sector business interests. ...

The resistivity of Constantan Essays

The resistivity of Constantan Essays The resistivity of Constantan Paper The resistivity of Constantan Paper The resistance of a piece of wire is dependant on its length, cross-sectional area and the type of metal the wire is made of. The resistance of a given wire can be calculated using the following equation: R = ? L / A where: L = Length (m) A = cross-sectional area (mi ) ? = resistivity of the metal By rearranging the equation the resistivity of the metal can be calculated: ? = R A / L The resistivity differs depending on the metal however it is constant at room temperature for each metal. This means that two pieces of wire made of the same metal and at room temperature should give the same result when calculating resistivity regardless of its length and cross-sectional area. The following equation can be used to calculate the resistance of a wire: R = V / I where: V = volts I = amps R = resistance When rearranged it can be compared with the equation of a straight line graph: V = R I y = m x (where m = the gradient) This means a graph plotted with volts against amps, the gradient of the graph will equal the resistance of the wire and from this the resistivity can be calculated. Constantan was chosen as unlike most metals, its resistivity does not change when the temperature is raised so the results will not be affected by the wire heating up. Method and apparatus Take two lengths of constantan wire, one 34 SWG (standard wire gage) and the second 30 SWG. Measure the diameter of each wire using a micrometer and then measure their lengths in metres. Set up the apparatus as shown in fig. 1 using the 30 SWG wire first and ensuring the power pack is on direct current. Using the rheostat alter the number of volts running through the circuit until approximately 3 amps is reached. Note the voltage and ensure the scale of volts used does not exceed this as the wire will get too hot. Use the rheostat to change the voltage to the first on your scale and note the amps. Repeat this until six readings have been taken. Set up the apparatus with the 34 SWG wire and repeat experiment. Plot a graph for each wire and calculate the resistivity of the constantan, both wires should give the same result. In the interest of safety all electrical appliances should be regularly checked. It is also important that the wire is not handled while in use in the experiment as it may heat up. To ensure little error the crocodile clips should be at the very end of the wire as the length is a factor in the calculation. If the wire curls onto itself and is touching at any point then this will affect the results as it will shorten the length of the wire the current must travel through. Apparatus: Ruler Voltmeter Micrometer Wires Rheostat Crocodile clips Power pack Amp meter Fig. 1 Results 30 SWG 34 SWG Volts i 0. 1 Amps i 0. 01 Volts i 0. 1 Amps i Discussion The resistivity of the two wires should have given the same result as they were both made from constantan, however the wires gave two different results. The 30 S. W. G. wire gave a result of 5. 49 x 10 ? m whereas the 34 S. W. G. wire gave a result of 4. 62 x 10 ? m. Although both wires gave a relatively close result to the expected value of 5. 49 x 10 ? m when tested, it does suggest some error was made. It was noted that all the experimenters present found they calculated a lower value for the 30 S. W. G. wire than that of the 34 S. W. G. wire. This may mean that the properties of the two wires differ slightly, perhaps because of a difference in the company that produced it or a different batch. The equipment used was limited as to how accurate the readings could be with the accuracy being i 0. 01 for the ammeter and only i 0. 1 for the voltmeter. This may have affected the results and could account for why the graph for the 34 S. W. G. wire did not form a straight line and so a line of best fit had to be drawn. The graph for the 30 S. W. G. did form a straight line as expected so perhaps there was less error in the testing on this wire. If the experiment was to be repeated, a more accurate voltmeter and ammeter should ideally be used. It may also be beneficial to use wires that come from the same batch and company to ensure this is not a factor affecting the results. Bibliography Kaye and Laby (1995) Physical and Chemical Constants 16th Ed : Longman Carol Slack Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.

Levendary Cafe case Study Example | Topics and Well Written Essays - 750 words

Levendary Cafe - Case Study Example However, the failure of this company and other companies in the Chinese market is not due to poor management. The failure has primarily resulted from failure to carry out a concise and thorough research. For example, Pretzel Time was unsuccessful in the market as a result of ignorance of proper sitting arrangements. This company overlooked the need to study and adapt decent decor. Hence, the tile dà ©cor they used in its establishment was for a bathroom. The failure by the designer of this company made it lose many potential customers. In addition, the other element which needs to be noted concerning entry into the market revolves around the VP’s decision to select many locations across the country. One can easily assume that VP’s objective for the entry was to ensure that the businesses succeed even during their first year of operations. The assumption is null, since your objective seems to have been to come up with a reliable market niche. From this, the business would have been expanded further. It seems that Chen’s choice of locations depended on their prices. Therefore, he wanted to reduce costs at all levels, so as to come attain his desired goal of achieving a successful business. It is also important to note that the plans to enter the Chinese market were poorly implemented. The poor implementation of the plans is depicted by how this company took long to realize its need to adopt GAAPs for accounting purposes of revenue collected. The VP considered this step to be so expensive. 1. The company needs to close down Chinese-like restaurants and to replace them with those restaurants that assume an American concept. This decision will be effective since competitors such as McDonalds and KFC have remained in foreign markets and still have a good customer base. 2. The headquarters, under your leadership, can embrace a mixed concept aspect. The aspect needs immediate change of the services offered so that at least two menus are served in

Leadership in management Essay Example | Topics and Well Written Essays - 2750 words

Leadership in management - Essay Example Opposed to this trait theory of leadership, evolved a system of understanding called the behavioural theories of leadership. Behavioural theories of leadership are based upon the idea that great leaders are made, not born. Rooted in behaviourism, this leadership theory focuses on the actions of leaders, not on mental qualities or internal states. According to this theory, people can learn to become leaders through teaching and observation. Conditioning occurs through interaction with the environment. According to behaviourism, behaviour can be studied in a systematic and observable manner with no consideration of internal mental states. Behavioral theories of leadership do not seek inborn traits or capabilities. Rather, they look at what leaders actually do. If success can be defined in terms of describable actions, then it should be relatively easy for other people to act in the same way. This is easier to teach and learn then to adopt the more ephemeral traits or capabilities. Thus , Behavioral leadership is a big leap from Trait Theory, in that it assumes that leadership capability can be learned, rather than being inherent. This opens the floodgates to leadership development, as opposed to simple psychometric assessment that sorts those with leadership potential from those who will never have the chance. A behavioral theory is relatively easy to develop, as you simply assess both leadership success and the actions of leaders. With a large enough study, you can then correlate statistically significant behaviors with success.