Should Stem Cell Research be Unbound Proposal Example | Topics and Well Written Essays - 4250 words

Should Stem Cell be Unbound - Research Proposal Example Spinal cord injuries and Parkinson's disease are two examples that have been championed by high-profile media personalities (for instance, Christopher Reeve and Michael J. Fox). The Coalition for the Advancement of Medical Research estimates that stem cell research shows promise to develop cures and/or new treatments for 100 million Americans who currently suffer from a wide variety of diseases and disorders. There are several types of issues to consider as we reflect upon stem cell research. ... Many frame the debate about stem cell research around the question of "when life begins," although the issue is not when life begins, but when personhood begins and ends. Human life began millions of years ago when our ancestors reached a stage of evolutionary development that permitted the separate species, Homo sapiens to arise. Human life will end when our species becomes extinct. Stem cell research is a controversial issue in America as, with the present state of technology, the creation of a human embryonic stem cell line requires the destruction of a human embryo. Stem cell debates have motivated and reinvigorated the pro-life movement. There has been a deep and bitter dispute over the conduct of this research; many pro-lifers, for instance, Roman Catholics and conservative Protestants, have opposed this research. According to them, the embryos from which these stem cells are extracted are actually individual entities and have a soul to them. Since the embryos are killed when the stem cells are removed, or stored for long periods of time, long past their viable storage life, pro-lifers view the extraction procedure as murder. In the United States alone, there have been estimates of at least 400,000 such embryos. However, not everyone is opposed to stem cell research. Many groups that even protest it are comfortable with certain forms of cell research. Plent y of experiments and tests have been carried out to determine improved and more efficient ways of saving lives and replacing organs, without having to kill â€Å"pre-embryos.†

The Story of Amy Tan Essay Example for Free

The Story of Amy Tan Essay The story about Amy Tans mothers effort to converse in effective English with people in spite of her broken or fractured English is in fact very common. I think many immigrants face this problem. As they come from a different background their way of thinking results into different Englishes. America has the most number of Englishes of the world as you can find people from all over the world here. I have seen people who dont take other people seriously who speak Broken English or in a certain accent. People use different Englishes everywhere; Spanish people have Spanglish, which is a combination of Spanish and English, Indian people have Hinglish, which is combination of English with Hindi the native language of India and so on. English is a universal language it is spoken slightly different everywhere which causes people to have a tint of background in their English. Why shouldnt people have their own tint of background in their English? People from different countries have different culture, way of thinking and even accents which adds the tint of background in their English. There is no doubt English is going to be spoken differently around the world. English is not only spoken but also written in some cases differently around the world. Such as the word Color Asians and British would spell it as Colour. As a matter of fact, even the MS Word Spell Check has it highlighted it as this is an American Software and Americans dont spell it like that. The word Schedule is pronounced as Sheadule. If everyone was speaking the same English there wouldnt be any difference if you are from England, China or any other part of the world. Everyone would sound the same and would have the same ideology. The diversity in English is in fact a good thing it shows ones cultural background and adds uniqueness to every country. So its fine to have tint of background in your English. These tints in English develop different accents all over the world. Not only all over the world but also in America. There are different accents such as the people from Southern states have different accent than people from the Northern. Not matter the accent English is still communicable and can avoid language conflicts. Language conflicts occur when there is no common language of communication or in other words when there are people speaking different languages and not everyone is aware of each others language. My friends family is very secular it consists of Hindus, Muslims and Portuguese. There are about three different spoken languages. To avoid any language conflicts they use a common language such as English so that everyone can understand each other. There are some people who get affected by difference in English; they are usually students from other countries studying in American Schools. These students often struggle with grades in English in American Schools, which is due to different Englishes. Amy Tan talks about how she struggled with grades in English and got by easily in Math and Science. This is true in the case of Asians as they have natural inclination towards technical subjects. The worlds leading Electronic and IT companies are loaded with Asians due to their natural ability. Asians in American Schools are usually steered away from writing towards Math and Science, which is why there arent many Asians Americans representing American literature. Amy Tan was a victim of such steering towards math and science. Amy Tan was told by her former boss that English writing was not her best skill and she should hone her talents towards account management. But she took all of the disproving assumptions that people made of her in a rebellious way and she over came it and succeeded. Its very annoying when people judge you by your background. As in the case of Amy Tan having Chinese background she was steered towards math and science in spite of her liking towards English writing. My following story is similar in a sense that I was also judged by my background rather than my capabilities. I had just moved from India to Canada and was hit with some irrelevant judgments that people made of me due to my background. The first impression that I got from Canadians was that they werent aware that Indians were able to converse in fluent English as they can. I saw that people were trying to talk to me in a way that I would understand them as if I didnt know English. I immediately informed them I can very well converse in the same English that they speak. I was shocked due to peoples lack of knowledge about third world countries. Its just said that English is our second language, but as a matter of fact English was taught to us before than our own language. Although we lea rned our own language since birth, but we really started reading and writing our own language from grade 3. Whereas we started reading and writing English from Kindergarten level. My classmates in Canada used to ask me whether we do Computer Programming in our own language since English is not our first language to which I replied; Absolutely not, we use the same English as you do, it might be a little different the way we use it but its the same language. I was truly amazed by the lack of awareness that people have about countries where the first language is not English. I had to prove a point that people can be well acquainted with English even if their first language is not English. Like Amy Tan I didnt exactly have any kind of shame in my story, as she feels a sense of shame and pride in her story. She feels shame because of her mothers broken English and pride as its because of her she is a renowned writer; its because of her she became rebellious in her life, wanting to accomplish something, prove something! And she succeeded in her life she achieved what she wanted to achieve. Although, I did have some pride in my story as I managed to change lot of peoples opinion and made good friends for life and had one of the greatest time of my life in Canada. I would conclude by saying that although English is diversified around the world due to language attitudes, difference in accent, background, Englishes or even unawareness to some extent, Its still the most communicable or reachable language in the world. I feel English is more or less like cooking; the taste of the same food differs from region to region and every region adds its own flavor to it.

Why I Study Biology Essay Example for Free

Why I Study Biology Essay Biology is fascinating in itself. It teaches us all the ways of life not just from a mankind perspective but through all living things, whether, human species, plants etc. I personally study biology because I want to discover the creation and functions of all living things in the world. Being a Psychology major means studying the mind and in order to better understand the human mind, you have to know the basics in the ways of life and how to incorporate the science of human nature into why people react to life differently, culture, religion, politics, etc. All of these factors are taken into consideration into Biology. This semester was extremely challenging for me, and there were a lot of factors that contributed to my inability to study as hard as I know I am cable of. Had my first child this year, was abandoned by my son’s father to raise my son by myself. To make matters worse, I had some medical complications with my health. I was diagnosed with a Pulmonary Embolism. This news was devastating to me. I was hospitalize for a long time and was so depressed. With all of my problems at hand I had to go to work and work 40 hours a week just so I could support me and my son. With all of these devastating experiences in my life, studying seemed impossible to accomplish the way I wanted to. I was constantly in and out of the hospital, worried about my health and trying to get well. Today I am still recovering and believing that God will bring me peace and happiness in me and my son’s life. Some things I could have done better in studying would be that I could have taken my studies to work with me and studied on my lunch. I never did this because I only had an hour to get lunch and eat and I always thought that if I did this I would end of being late coming back from lunch. Another thing I believe would have helped me study better this semester is a strong support team. I did not have many people to help me like I needed. If I had someone to assist me while I studied I could have been a lot more successful. Instead I had to study and care for my son and that was difficult. Finally, when I think about my future in continuing with my courses, I know that I have to study even when I am tired. One bad habit that I had was when my son was sound asleep; I would try to get a few hours asleep as well so that I could be rested for work the next day. One thing I could have done to help me be more successful is to push myself just a little harder, and I ultimately believe I did not push myself to the max because I was so concerned about my health and stress was a trigger for me to feel sickly and I was so overwhelmed with everything going on in my life. What I hope to accomplish in the future is to be successful in my studies and to obtain my BA in Psychology and get my master’s as well. I have learned one thing through everything that I have been through. I reasoned with life from this analogy, life is like a game of baseball, anything that life pitches at you, it is you that have to ready to swing at any time. Whether it’s a fast ball, trick ball or curve ball, you have to prepare yourself for victory. If your just focus getting a home run, whether you struggle getting there or not, what matters is that you give your best to win.

Static Channel Versus Dynamic Channel Allocation Systems Computer Science Essay

Static Channel Versus Dynamic Channel Allocation Systems Computer Science Essay Abstract- Channel Allocation Schemes have always held a vital role in achieving better performance of wireless networks. This paper has studied the comparison between two of the most known techniques of channel allocation namely: Static Channel Allocation and Dynamic Channel Allocation. The comparison is made over two types of networks single radio network, in which each of wireless node is equipped with only one radio interface, and multi radio network, in which each of the node is equipped with at least two transceivers. This paper presents the detail survey of all the existing comparison made between these two schemes. Keywords- Channel Allocation Scheme, Dynamic Channel Allocation, Static Channel Allocation, Single radio network, Multi-radio network Introduction Growth in the customers of the wireless networks, let it be cellular systems or any other Wireless network, has amplified the need to have the networks which can have more capacity and accommodate more and more users. Enlargement of wireless market has made capacity of the wireless network a scarce resource. Methods to improve effective capacity utilization of the wireless network are under consideration and in [4], it is realized that these methods involve source coding schemes, power control, better modulation schemes, improved antennas. Other then these methods capacity of wireless system can be improved by installing more bas stations i.e increasing number of transmitting equipment or improving hardware equipment of current system. Using better channel allocation schemes is also one of the methods to improve capacity utilization of wireless network. The aim of this paper is to focus on channel allocation schemes. These channel allocation schemes are not much of importance in the wired networks because their topology is stable and they do not offer any mobility to the users/nodes. But in the wireless networks, channel allocation of key importance. The vital role of the wireless networks is that they offer mobility to users hence, the channel allocation algorithm has to assign channels to ports and portables so that best trade-off between the quality of service and system performance is maintained [3]. A given spectrum of frequency, can be divided into several independent sets, these independent sets are completely disjoint with each other. Hence even if they are used simultaneously, they will not interfere with each other. So splitting the frequency spectrum into independent channels and then using all the channels for communication simultaneously present improvement in the capacity utilization [6]. The channel allocation strategy is considered to be the core of mobile networks because it not only affects the quality and the availability of the channels to the user but changes the distribution of the traffic and hence, overall shapes the capacity of the network [3]. Two of the most common channel allocation schemes are considered in this paper namely, FCA- Fixed Channel Assignment or Fixed Channel Allocation and DCA- Dynamic Channel Allocation. Fixed Channel Allocation (FCA) Fixed Channel Allocation is also known as Static Channel Allocation. It is known as Fixed or Static because once the channel is allocated to a port or a user it does not change for the entire course of operation. It is used in all TDMA/FDMA digital cellular mobile networks [5] as number of frequency carriers in each cell stays fixed and does not depend on traffic load. It is a time insensitive solution, as with the passage of time allocation of the channels to nodes does not change. Although in real-time, traffic load in a cell varies, there are peak hours when the traffic load reaches to almost 100% and then there are quiet hours in a cell when traffic load is very low. This limitation dispirits the use of the FCA. But if a static condition is considered there is most likely a chance to get good performance with this channel allocation algorithm [3]. In a cellular system based on the FCA, channels are partitioned among the cells permanently so that if all the cells use all the channels assigned to them simultaneously, there will be no interference [1]. Figure cell pattern for Static Channel Allocation with N = 7 With more complex systems other channel strategies can achieve higher efficiency but they require processors with more memory. But it is an essential sacrifice to make as in [4] it is discussed that in each cell there are no static conditions, space traffic imbalance varies from 10% to 70%, and this imbalance in the traffic depends on the size of the cell or service area and type of the environment, whether its urban, suburban or rural area [4]. Dynamic Channel Allocation (DCA) In DCA, frequency channels are not fixed for any node or user. Depending upon knowledge of the environment, channels are assigned to the user. The distribution of the frequency carriers in a cell depends upon distribution of the users/nodes in the cell and also on offered traffic load. DCA is currently supported by the GSM [5]. In Dynamic Channel Allocation Scheme all the channels which are available for a system, are kept in a queue or a spool. These channels are allocated to any cell temporarily. The only constraint is to fulfil the distance criteria, so that interference can be minimized [2]. The existing schemes for the Dynamic Channel Allocation can be categorized into three main types: IA-DCA (Interference Adaptive Dynamic Channel Allocation), LA-DCA (Location Adaptive Dynamic Channel Allocation) and TA-DCA (Traffic Adaptive Dynamic Channel Allocation), these schemes are based on the type of network dynamics they consider while making decision [4]. All DCA schemes basically evaluate the cost of using each available channel and opts the channel which introduces lowest cost [2]. For most accurate and good decision for channel allocation, the algorithm should have accurate knowledge of the environment [3]. The main algorithms which are considered under the study of Dynamic Channel Allocation are: DCET, Bellcore and Segregation DCA [3]. In DCET and Bellcore DCA algorithms, the decision of channel allocation is based on only single measurement of channel dynamics, while in the Segregation DCA, a radio interface acquires the channel depending upon its learning through past experience of channel usage. With the past knowledge, channel which has highest probability of success is chosen for operation. Although this algorithm requires processors with memory yet as decision is more meaningful so its performance is better than the DCET and Bellcore DCA algorithms [3]. In figure 2, in [7] results of performance of different type of DCA schemes are compared. Figure Performance of Different DCA methods Section II of the paper compares both of the channel allocation schemes in a single radio network and Section III shares the comparison done of channel allocation schemes in multi-radio network. Section IV shares the identified regions in which future work can be done and Section V concludes the paper. Comparison of DCA and FCA in Single Radio Network A single radio network a network in which all of the nodes of the wireless network consist of maximum of one radio interface and this single radio interface is used for the communication purposes. In this section the comparison of the DCA and FCA in single radio network is presented. Figure Algorithms for Dynamic Channel Allocation In a given cell, if a node requests a call, it will be served only and only if the cell has an unused channel available, which fulfils the reuse criteria, otherwise the call will be blocked [1]. Such is the case with Static Channel Allocation Scheme. But this is not the case with the Dynamic Channel Allocation Schemes, as for each of the call that is to be served; channel is taken from the overall pool that holds all the channels available for wireless system. In any channel allocation strategy, main aim is to find the best possible way to reuse the channels to maximize the systems capacity, while keeping interference in the system at minimum and provide quality of service to the user [4]. From another view, for allocating channel, the objective is taken as to allocate the channel to a call so that number of blocked calls is minimized and the number of dropped calls is also minimized. In the end, the channel allocation scheme finds the best trade-off between these two objectives because generally priority is given to minimize the number of dropped calls, as having a call dropped is more undesirable then not having the call connected at all [1]. Both schemes for channel allocation FCA and DCA are compared under the assumption that the call arrival distribution is Poisson [5]. For the purpose of modelling in FCA it is considered that there are z numbers of channels per frequency carrier and y is the number of control channels. In a given cell i, let total number of frequency carrier be Ci and the total number of channels in the cell, which will be used to serve a call will be ci. The expression for ci is given as: (1) While this will not be the case for DCA, as frequency carriers are not permanently assigned to any of the cell. As the channel assignment depends on environment so, if we take n as the number of active calls in any cell, then frequency carriers allocated to that cell will be: (2) Total number of channels required, for any cell should be equal to the number of active calls and the control channels. But the number of frequency carriers which has z number of channels each should be either more or equal than actually required [5]. In equation (2), shows that value is always taken equal or greater than a [5]. For the first simulation, the arrival rate of the calls is set at the overload value; this means that the overload period is considered where the numbers of calls initiated per minute are more than the actual capacity of the system. The observation made over here is that, under heavy traffic load, efficiency of the network or the channel utilization and capacity of the network does not improve by using DCA instead of FCA. Although it was considered as the fact that DCA will always perform better than FCA. Figure Effect of the handover on FCA and DCA In figure 4, the phenomenon observed is known as phenomenon of low capacity island [5]. Under heavy load, no benefit is achieved by using DCA, as in such a scenario both of the schemes will be utilizing capacity to the full extent. Rather DCA may perform worse than FCA. The reason is that due to dynamic channel allocation, a cell may borrow some of the frequency channels form the neighbouring cells during the low traffic period and the neighbouring cell does not get the channel back. The cell which has obtained the channel is let us say known as the lucky cell, and the cell which donated the channel and in the end, was unable to get it back is known as unlucky cell [5]. Now during the high load traffic period, if lucky cell wants to handover the call to a neighbouring unlucky cell. But as the unlucky cell would already be out of available channels to be able to serve the call, call will be dropped. Hence under such a scenario the drop out probability of dynamic channel allocation sch eme would be higher than static channel allocation algorithm. Other simulation is to find out the effect of the arrival rate on call blocking probability. Arrival rate is the number of calls initiated per minute. Through simulation, it is concluded that DCA performed better if the traffic load is within the range 0.6 to 0.9 Erlang/BS/Channel. (figure 5) Figure Analysis of DCA and FCA, call blocking ratio with respect to the arrival rate of the calls During the next case it was considered that arrival rate is Poisson and the other parameters like handover rate and call holding time etc are evenly distributed all over the cell. From the figure 6 it is clear that as probability of call blocking increases with the increase in the arrival rate of calls. Which is fairly obvious, more are the number of the users which are to be served, there is more likely a chance that some of them may not be able to get a free channel. Figure Performance analysis of FCA and DCA, Arrival rate of calls with respect to the over all blocking probability Under such consideration as can be observed from the figure 6, DCA performs better than FCA, as in case of congestion in a cell, DCA can borrow channels from the neighbouring cells but in case of FCA, the scheme has no option but to reject the oncoming calls in case of congestion. Figure 7 shows the amount of traffic carried by FCA and DCA according to the traffic load. Figure comparison between FCA and DCA with respect to the carried traffic under the traffic load Figure 8 shows the performance of the channel allocation schemes when traffic imbalance is considered. It is observed that network capacity to carry data, in case of FCA, reduces significantly when data imbalance is considered. But in case of DCA, there is no significant degradation in networks capacity to carry the data. There is also significant increase in the number of calls blocked by FCA, because of the increase in the traffic imbalance. But as the carried capacity does not decrease much in case of the DCA, there is not much of the increment in number of the blocked calls. Figure FCA Vs. DCA, effect of the traffic imbalance on the both channel allocation techniques Comparison of DCA and FCA in Multi Radio Network A multi radio network is the type of the network where each node is equipped with at least two or more than two transceivers. Fixed Channel Allocation in Multi-radio network It is pointed out in [14], throughput and overall performance of wireless networks decreases with increased density of radios, but major reason for this problem is that these radios do not transmit the data simultaneously as the nodes are generally configured with single radios only and this factor basically limits the forwarding capacity of the network. In [15], the authors have emphasized that with the introduction of more than one NIC (Network interface cards) in wireless networks, performance of the system can be improved 6 to 7 times, instead of just doubling the performance. The same phenomenon has been confirmed in [16]. There has been much work done, in which the performance gain in wireless mesh networks with multiple interfaces is discussed as compared to single radio interface network. In [13], capacity gain between single radio, dual radio and multi-radio wireless mesh networks is compared and realistically the gain achieved by having multiple radio interfaces in the network has been discussed. Apart from that, in [17], authors have proposed that with implementation of multi-radio Diversity approximately 2.3 times performance gain is measured in the single radio network. Under the multi-radio scenario, one important factor is to consider proper channel assignment. Each of the radios should be tuned to a frequency through which the throughput of the whole network is maximized. The introduction of multiple radios is not without the trade off of increased complexity of channel assignment schemes and the traffic allocation methods [20] and apart from that, more work is done in this domain. In [10], [8], [19], the authors have proposed some approaches to get maximum possible throughput by different channel assignment algorithms. The concept of the Static Channel Allocation in this section is extended to Wireless Mesh Networks, as before the start of the operation in the wireless mesh networks the channels are properly allocated and then till the end of the operation, the channel assignment does not change. In this section, multi-radio wireless mesh network is considered and it is observed that how by having multiple radio interfaces the performance of the network improves. Figure Performance of the FCA algorithms with 3 channels Figure 9 shows the impact of the different algorithms for the channel allocation in the three channel scheme [8]. Figure performance of the FCA algorithms with 12 channels Figure 10 shows the impact of the different algorithms for the channel allocation in the twelve channel scheme [8]. Figure 11 shows that with different channel allocation algorithms, how the increment in number of interfaces per node impacts the performance of network. In all algorithms it is observed that with the increase in number of radio interfaces per node, throughput of wireless networks improves [9]. Figure FCA algorithm comparison with different number of radio interfaces per node Figure effect of increased number of interfaces per node on the over all normalized broadcast latency In figure 12, it is shown that with different channel allocation schemes for multi-interface wireless mesh network, normalized latency for broadcast decreases with the increase in number of radio interfaces per node [9]. In figure 13, it is simulated that with the increase in the number of interfaces per node, there is not an unlimited increment in capacity utilization. Multi radios are used so that in a network there could be as many concurrent transmissions as possible. But even this has a limit to it. In [10], it is shown that after achieving the maximum level of capacity utilization, even after by adding more number of radio interfaces in a network, no advantage is gained. Figure capacity degradation with increase in the number of radio interfaces per node Figure Effect of the number of channels and multiple radio interfaces on the throughput In figure 14, it is shown that as long as the number of the available channels in a cell; are more than the number of interfaces per node, with increase in number of radios per node, throughput of the network will increase [11]. Figure throughput increment of a network by increased number of the interfaces per node In figure 15, it is shown that under a proper channel assignment and routing method, with more number of interfaces per node, the throughput of the system improves considerably [12]. In [13], as shown in figure 16 and 17, performance of fixed channel allocation scheme is compared in detail with respect to single radio network and the multi-radio network. Figure overall network capacity increment with more number of radio interfaces present at each node In figure 16, it is proved that the capacity of the overall system improves with the usage of multiple radios per node. Figure capacity of each AP with multiple interfaces per node Comparison between single radio to the multiple radios In figure 17, per Access Point capacity is simulated to have comparison between multi-radio interface per node and single radio interface per node. Dynamic Channel Allocation in Multi-radio Network: There has been little work which proves the introduction of multiple interfaces while using the Dynamic Channel Allocation provides any performance up-gradation. Analytically it is assumed that, as the introduction of multi-interfaces in wireless mesh networks improves performance, similarly the performance of networks using Dynamic Channel Allocation can be improved by introducing more than one interface on a single node. Some of the analysed parameters, which show the relative improvement in performance, are listed below: Parameter I: Improvement in the throughput of the system: In a single radio cognitive network, as shown in figure 18, the node D has two data packets of equal size in its internal queue, one for node C and one for node. Nodes E and C are at the equal distance d from the node D but are tuned at different channels. In this particular case each packet will take time t to reach the destination. Even if we neglect the switching time, cognitive radio present at D will take to switch from one channel to the other channel, the time taken to completely transmit both of the packets will be t+t = 2t. Figure Single Radio Network Now even if the same network topology is considered but now consider that each of the nodes is equipped with two interfaces (figure 19). Node D will be able to transmit both of the packets simultaneously to node C and node E, considering that interface 1 is tuned to the channel on which communication with node E is possible and interface 2 is tuned to the frequency over which communication with node C is possible. In this case there will be no delay caused by the switching of the channel. Figure Multi-interface radio network Figure Effect of channel switching Conclusion: The transmission time is decreased with the factor of N, where N is the number of interface each of the node will have. Throughput is improved with the factor of N. Parameter II: Latency of the network will decrease: With the introduction of the multiple interfaces in the cognitive radio network, latency of the network will decrease. Figure Multi-hop Single interface Wireless Network Initially considering the multi-hop scenario, considering an intermediate node, it has to receive an incoming transmission on channel 1 and then it has to tune its radio to the channel 2 to be able transmit the received transmission to the destination node. Latency of such network will consist of: Transmitting time of packet over channel 1 from source node to intermediate node: t1 Transmitting time of packet over channel 2 from intermediate node to destination node: t2 Switching time required for the interface on intermediate node to switch from channel 1 to channel 2: t3 Hence the total latency of such a system will be: t1+ t2+ t3 Figure Multi-hop Multi interface Wireless Network Now comparing the previous scenario with the one in which each of the node is equipped with at least two interfaces. Now on the intermediate node interface 1 will be tuned to channel 1 and interface 2 will be tuned to channel 2. If there is an incoming transmission on channel 1 and it is to be transmitted to the channel 2, the total latency will be: Transmitting time of packet over channel 1 from source node to intermediate node: t1 Transmitting time of packet over channel 2 from intermediate node to destination node: t2 Hence the total latency of such a system will be: t1+ t2 The switching time will not be considered over here; hence comparatively the latency is decreased with the introduction of another interface on the cognitive radio node. Conclusion: The latency factor is dependent on switching time of the cognitive radio. This factor comes into effect with more dominance with increase in the number of hops in the multi-hop network. Latency can be greatly reduced with the introduction of multi interfaces on the cognitive radio network. Parameter III: Connectivity of the network will improve: The probability of isolation of any node in a network will be reduced with the introduction of the multi-interfaces in the cognitive radio network. Figure Single interface node with the available channels Considering the scenario, in figure 23, where a secondary network has four channels available for its utilization, now for a given condition, all radio interfaces are tuned to either one of the channel 1, 2 or 3. If a single interface chooses channel 4, it will be isolated from the rest of the network. Assuming that the probability of opting for such a channel is p then the overall probability of getting a node isolated from the rest of the network will be p. Figure Multi-Interface node with the available channels Now for multiple interfaces, a node will only be separated if both the interfaces of a single node choose channel 4. A node will be isolated if and only if: Interface 1 chooses channel 4 AND interface 2 chooses channel 4 P2 As according to the probability rules p Conclusion: The probability of isolating a node, is decreased with the factor of N [N is the number of radios] as compared to the probability of node isolation in case of single interface cognitive radio networks. Here mutual independence among the DCA algorithms running on both of the radio interfaces is considered, but this is not generally the case. The performance of a cognitive radio network is strictly dependent on the number of cognitive radios present in its vicinity [21]. Figure Improvement in throughput using multiple radios Figure Improvement in throughput of the network with multiple radio using different number of available channels Figure 25 and 26 shows the throughput improvement gained by the introduction of multiple radios as compared to a single radio and in both of the figures different number of available channels are considered [24]. Comparison: Up till so far, none of the research has been carried out to find out whether any advantage is gained by deploying Dynamic Channel Allocation scheme in the multi-radio wireless network domain as compared to the implementation of the Fixed Channel Assignment algorithm. Considering the study made regarding the performance improvement gained by fixed channel allocation scheme and dynamic channel allocation scheme in multi-radio wireless network, there could be several hypotheses made. The complexity of implementation of Dynamic Channel Allocation algorithm will be more than that of Fixed Channel Allocation algorithm. Although the same is true in case of single radio network, but in case of the Multi-radio network, the complexity increment will be more significant. The reason can be taken as if the spectrum view of a single interface of a node changes in multi-radio network, for the similar node the situation changes for the other interfaces as well [21]. The performance improvement obtained by implementation of the Dynamic Channel Allocation algorithm as compared to the Fixed Channel Allocation in the multi-radio will have similar effects as it has in the Single radio network. The same effect on the throughput of the system, data carrying capacity and the effect of the traffic load and traffic imbalance will be observed. Another important factor that can be predicted because of the observation made via simulation figures is as the performance of the wireless network depends upon the density of the nodes in a network. As compared to the Fixed Channel Allocation Scheme, Dynamic Channel Allocation Algorithms will be more sensitive to the density of the network [23]. There will be no matter of connectivity in case the Fixed Channel Assignment Scheme is deployed on the wireless network. As before the point of operation with FCA, it is made sure that all of the nodes are connected and none of the node is left isolated. With the Dynamic Channel Allocation there will still be a small probability that a node can get isolated from the rest of the network. In the Fixed Channel Allocation for the multi-radio wireless network the distribution of radio interfaces do not matter for the performance. But in case of the DCA, better performance can be improved if radio interface distribution on the nodes is not uniform. DCA will perform better if the first hop nodes have more number of radio interfaces than rest of the network nodes [22]. Future Work The points raised, during this study are just concluded through observation and analytically studying the response of the Fixed Channel Allocation Algorithm in the Multi-Radio network and Dynamic Channel Allocation Algorithm in Multi-Radio Network. These observations can be further improved by using proper simulating tools. Conclusion In the single radio wireless network, DCA exhibits better performance than FCA. The same behaviour is predicted for the multi-radio wireless network, but with the increased complexity. And much better performance can be achieved by taking care of the distribution of the radios in the network. Still it should be considered that there will not be infinite performance gain obtained by using multi-radio network and DCA. The limitation imposed is that number of channels available to a cell should always be greater than the number of interfaces per node has.

Dialectoc Composition In Purgatorio V :: Purgatorio V Poem Poetic Essays

Dialectoc Composition In Purgatorio V In this canto there appear to be none of those cruces on which contemporary criticism often fastens as basic for the understanding of the poem's deeper meaning. It nevertheless contains some of the most vivid episodes of the journey, especially in its second part, involving the stories of three memorable characters. As is characteristic of the whole cantica, and is especially evident in the first cantos, we find that the three souls we meet here are, by the very definition of their realm, in a liminal state between two forms of existence, the earthly and the celestial. They are gradually shedding the prejudices and passions that had made them cling to the illusory goods of their earthly existence, and getting ready, through their painful purgation, for the permanent bliss to come. We shall see how, by the very progression that distinguishes them among themselves, the three main characters are increasingly detached from the worldly values and increasingly ready for the final step. In one of the more recent  «lecturae » Giambattista Salinari (1969, 311 and 313f) finds that this canto is marked by a high degree of lyricism, considering the progression of the three generic ingredients of the whole poem, namely the descriptive (or epic), the dramatic, and the lyric. He also stresses here the particularly conspicuous presence of what he calls the three types of  «contrappunto » in which Dante excels, namely the  «horizontal » (when contrasting episodes are juxtaposed for the sake of variation and emphasis), the  «vertical » (when over several characters the same situation or theme is developed through rising tonalities), and finally the  «stylistic » (when in the same episode the epic or narrative element is expressed through elegiac description, the dramatic through dialogue, and the lyric through monologue). This is, in short exposition, an interesting analytic point that concerns a striking yet little noticed feature of Dante's method o f composition, and which this writer has attempted to define and analyze under the term of  «dialectic composition ». The structure of Purgatorio V leans, as it were, backward and forward, tying in with the conclusion of the episode of the lazy in the preceding canto and then concluding the episode of the violently slain, who properly occupy this canto, in the following canto, when the same group continues to crowd around Dante in order to secure prayers on their behalf from the living.

Plato and Lockes Views on an Innate Idea Essay -- Philosophy essays

Plato and Locke's Views on an Innate Idea      Ã‚  Ã‚  Ã‚   What is an innate idea?   This can be defined as some idea or mental representation that is produced by outside perception or created anew by our imagination. It exists in the mind in virtue of the nature of the human mind.   According to Plato most if not all of our knowledge is innate. However, John Locke feels that we do not have any innate ideas.   Then the question arises of who is right or are they both wrong.   In this paper I will attempt to examine the conflicting views of Plato and Locke.    The problem that I will be dealing with involves the different views of Locke and Plato.   The main focus of the paper will be to deal with both sides of the view on innate ideas and determine which is plausible. I will be looking particularly at Plato's treatment of the concepts in the Meno and Locke's treatment in certain parts of the essay on human understanding.    It is very hard to determine what if anything the mind possesses.   It could possess everything we will ever know, as Plato seems to think, or the mind could possess nothing.   Both of these views will be discussed in the following paper. Plato's view on knowledge stems from Socrates and his teachings.   Socrates claimed to not know what virtues were or if they existed.   However, he develops a peculiar view of ideas and knowledge acquisition. [Meno 70-100b].   First, I will begin by setting up the background of the Meno.   Socrates has been on a quest to find if anyone knows what virtues are and who has the virtues.   While in the process of this Socrates makes many enemies.   At the beginning of the d... ...the experience at hand.   When we learn from this experience it is engraved on our minds or slates. Locke is a model empiricist.   But I also feel he should compromise on the issue of innate capacities.   This would allow for all the knowledge we gain from experience to be filtered and classified to further our learning.   Therefore, we would have no innate ideas but we would gain our knowledge from experiences.   However, we would have the innate capacities to filter our knowledge. Works Cited Brown, M. (1971). Plato's Meno. New York: The Bobbs-Merrill Company, Inc Chappell, V. (1994). The Cambridge Companion to Locke. New York: Cambridge University Press. Chappell, V. (1998). Locke. New York: Oxford University Press. Cooper, J.M.,(1997). Plato: Complete Works. Indianapolis, IN : Hackett Publishing Company.

Gay, Lesbian, Bisexual issues - HIV Positive Children Must be Allowed t

HIV Positive Children Must be Allowed to Attend School Do you remember when Ryan White tried to attend public school in the 80's? Remember the media blitz and all the panic of the community? Parents and teachers were afraid to let HIV+ children attend public school. There was a fear that children with AIDS would somehow infect their healthy classmates. The truth is, AIDS is a disease which is not transmitted by casual contact. Normal play and interaction with HIV+ children is no threat to healthy children. So in recent years, fears have subsided and the policies of many school districts have changed. In Oklahoma for example, the Putnam City School District now allows HIV+ children to attend its schools. As a result of the District's decision, the people involved in the schools are reaping life-enriching benefits. First of all, the healthy children who attend Putnam City schools experience significant benefits by routinely interacting with classmates who have AIDS. Perhaps the most important benefit healthy children gain is they learn to fear the disease itself, not persons afflicted with it. Healthy children soon realize they can not only talk to but also study beside and even play with their AIDS infected classmates without fear. On the other hand, they clearly learn to fear the disease itself, for children who are friends with HIV+ children watch their friends slowly die. Christy's experience with her friend, Mark, is a typical example. Christy had known Mark since they were in kindergarten. Mark was a hemophiliac who had contracted AIDS at the age of seven via the clotting factor medication he had to take for his condition. When he was 11, Mark developed full-blown AIDS, and AIDS claimed him when he was only 15. Christ... ... and they are included in social activities beyond the school environment, such as going to the mall, the movies, and restaurants. These opportunities help the AIDS infected young people enjoy a happier life, even if it is tragically short. It is unquestionable that Putnam City School District's policy of allowing HIV+ children to attend their schools has benefited all involved. First, parents' fears that their healthy children would be in grave danger from casual contact with AIDS infected children have been proven false. Second, healthy children have gained a respectful fear of a deadly disease, a wisdom they probably would not have gained had they just been isolated from the horrors of AIDS. And finally, HIV+ children have taught their peers and adults alike that it is people who count, that all people need friends, and that all have the right to be educated. Gay, Lesbian, Bisexual issues - HIV Positive Children Must be Allowed t HIV Positive Children Must be Allowed to Attend School Do you remember when Ryan White tried to attend public school in the 80's? Remember the media blitz and all the panic of the community? Parents and teachers were afraid to let HIV+ children attend public school. There was a fear that children with AIDS would somehow infect their healthy classmates. The truth is, AIDS is a disease which is not transmitted by casual contact. Normal play and interaction with HIV+ children is no threat to healthy children. So in recent years, fears have subsided and the policies of many school districts have changed. In Oklahoma for example, the Putnam City School District now allows HIV+ children to attend its schools. As a result of the District's decision, the people involved in the schools are reaping life-enriching benefits. First of all, the healthy children who attend Putnam City schools experience significant benefits by routinely interacting with classmates who have AIDS. Perhaps the most important benefit healthy children gain is they learn to fear the disease itself, not persons afflicted with it. Healthy children soon realize they can not only talk to but also study beside and even play with their AIDS infected classmates without fear. On the other hand, they clearly learn to fear the disease itself, for children who are friends with HIV+ children watch their friends slowly die. Christy's experience with her friend, Mark, is a typical example. Christy had known Mark since they were in kindergarten. Mark was a hemophiliac who had contracted AIDS at the age of seven via the clotting factor medication he had to take for his condition. When he was 11, Mark developed full-blown AIDS, and AIDS claimed him when he was only 15. Christ... ... and they are included in social activities beyond the school environment, such as going to the mall, the movies, and restaurants. These opportunities help the AIDS infected young people enjoy a happier life, even if it is tragically short. It is unquestionable that Putnam City School District's policy of allowing HIV+ children to attend their schools has benefited all involved. First, parents' fears that their healthy children would be in grave danger from casual contact with AIDS infected children have been proven false. Second, healthy children have gained a respectful fear of a deadly disease, a wisdom they probably would not have gained had they just been isolated from the horrors of AIDS. And finally, HIV+ children have taught their peers and adults alike that it is people who count, that all people need friends, and that all have the right to be educated.