Tuesday, March 24, 2020

Art Essay Essays

Art Essay Essays Art Essay Essay Art Essay Essay Fearing a Savage Goyaâ„ ¢s painting, Saturn, comprises of a man being appalled by an unknown creature, as in Goldings novel, Lord of the Flies, the boys stranded on the island are in fear of a snake like beastie that haunts the island. Goya and Golding exhibit the emotional state of humans when intimidated by the unknown by creating a vivid series of images throughout with a unique style, mood, and a concrete symbol. The images that are in the painting, illustrate a very gruesome creature consuming a human being pleasurably. This thought can also be found throughout the novel, in the minds of the littluns. Once the boy with the mulberry mark on his face, claimed that he saw a snake-thing, all the littluns were terrified by this creature or beastie (Golding 35). The painting exemplifies this idea of imagination. Another way, both Golding and Goya exhibit the emotional state of humans when intimidated by the unknown is by setting a unique style. In the novel, Golding has a very simple style with deep subject matter. The painting compliments this, through a very simple picture. The painting of the creature isnâ„ ¢t too detailed but has a very disturbing thought. The mood in both the image and the novel are complimentary at definite times. The image through the use of very dark colors gives a dark, solemn, bloodcurdling gruesome mood. This same mood can be found when the littluns dear is talked about. An additional technique that both Golding and Goya both use to exhibit the emotional state of mind when intimidated by the unknown, is symbolism. In the novel, the imagination is shown as very wild and impacting. Once the littluns heard, the boy with the mulberry mark on his face, talk bout the creature their imaginations created their own picture due to the lack of details provided. The image, illustrates one possible appearance of the beastie. Both the painting and the images in the littluns minds all symbolize manâ„ ¢s fear of the beastie. Fear of anything that can possibly harm him. Fear of anything unknown. Chapter 2, Fire on the Mountain, and in the painting , Saturn by Goya, both build a foundation to initiate the fear that spreads drastically throughout the novel. The painting exhibits fear of a creature. Which can lead to fearing anything unknown, this fear has been demonstrated that it can take away nobility and turn humans into dangerous savages. These dangerous savages can even take life away with no emotional or mental destruction, as exposed in the painting.

Friday, March 6, 2020

Heroes in English Literature

Heroes in English Literature Heroes in English literature constitute a majority of the middle Ages narratives. In epic plays, poems and narratives, heroes were defined as being selfless individuals who deliberately and courageously risked their lives for a justified cause.Advertising We will write a custom essay sample on Heroes in English Literature specifically for you for only $16.05 $11/page Learn More They are said to overcome risky and dangerous obstacles for the benefit of others. In the middle Ages, there is a variety of literal text that depicts heroes. These include epic heroes like Beowulf, romantic or chivalric heroes like Lanval and Lord Gawain and the green Knights (Kline 27). This middle Ages narrative will form the basis of this paper in showing the comparison of these heroes. Then what qualities were deemed to characterize these heroes in the middle ages? From the above mentioned epic heroes, we find that the aspect of heroism is differentiated mostly to suit the time i n which they were written and also to meet the expectation of the audience and preference at the time. In Beowulf, we find that heroism was depicted by being courageous and brave. This is demonstrated by Beowulf who travels far and wide to prove his strength. From the story, it is evident that the community which was the Danes of Denmark and the Geats who constituted Beowulfs own people valued not only physical strength as an attribute, but also the aspect of being selfless for the greater good. This is demonstrated when king Hrothgar of the Danes great hall called Heorot is attacked by a demon called Grendel and kills most of the kings men. It is prudent to mention at this juncture that Beowulf being an epic poem starts at the Medias res. So we learn through narration of king Hrothgar to Beowulf that Grendel has been attacking the village and killing the people (Heaney 56). Beowulf is depicted as a hero because of his ability to defeat Grendel without being armed. According to the story, Beowulf severs Grendel’s arm. Being mortally wounded, Grendel retreats to his borrow to die, but this is not the end of king Hrothgar tribulations as Grandel’s mother avenges her son’s death by killing king Hrothgar close friend Aeschere, Beowulf swears to avenge Aeschere death and goes after Grendel mother in the swamps and kills her by her own sword, heroism in this case is depicted by the ability of the hero or heroin to defeat super natural demons, its a matter of mortal being verses supper natural beings.Advertising Looking for essay on british literature? Let's see if we can help you! Get your first paper with 15% OFF Learn More According to some analysts, epic narratives were meant to depict a man as being in control of his fate and that his destiny was not predetermined by the supernatural beings. At the end of the story we see Beowulf fighting a dragon that had ravaged his kingdom and, although this is fifty years after ki lling Grendel’s mother and himself being old, he still has to prove his ability. Thus, he goes after the dragon and although he managers to kill it, it is at his own demise because he shortly succumbs to death. In Beowulf’s case, a hero is the one who gives his life for other to live. Although Beowulf forms what we may refer to as traditional form of epic poems, Marie de France in Lanval introduces us to a different aspects in terms of how epics were viewed traditionally. Normally, heroes were men who were supposed to save the women at all cost even to their own peril, but in Lanval, it is the direct opposite where it is the woman who saves the man. The reason given for this drastic change from male centered epics that depicted males as being heroes and females being villains is the fact that Marie de France lived in the era of Eleanor of Aquitaine who herself loved plays that women played important roles. In Lanval, the story is about a knight called Lanval who sits a t king Authors table and is overlooked by King Author and rest of the kings official, feeling depressed for having nothing and most importantly land (Marie De France 1-2). He rides of to the countryside to clear his head. Marie de France adopts the fairy mistress motif that is traditionally used in Celtic stories, where a beautiful lady comes from another world and falls in love with the man, but there is a catch, the man should never reveal their love. If the man breaks the pact, then he is punished by the fairy lady by withdrawing her love. Lavals case is not so different, but heroism is depicted by the virtue of love rather than physical strength as was the case in Beowulf. At the time of this writing, the society seemed to uphold the truth and no wander when Lanval stood accused at the court by Guinevere, king Authors wife who wants to have an affair with Lanval, when Laval refuses to engage in such an act Guinevere accuses him of being a homosexual, but Laval sticks to his deci sion saying that he cannot betray king Arthur. Lanval is forced to confess his love to the fairy lady. He is told to prove that he has a lover or else be banished knowing very well that he had broken his world to her fairy lady. He knows that she would not turn up and so prepares to be banished, but out of the blues, she appears in front of the court and confesses her love for Lanval. The story culminates in both Lanval and her fairy lady ridding towards the sunset.Advertising We will write a custom essay sample on Heroes in English Literature specifically for you for only $16.05 $11/page Learn More Marie de France takes epic poems to the next level where heroes suffers for doing the right thing this is typical of Shakespearian tragedy where doing the right thing is the cause of a hero falling from grace to grass, but unlike Shakespeares tragedy that culminates in a sorrowful mood with the demise of the hero, Marie de France culminates Lanval on a happy end ing, where justice is served. Heroism in this aspect is depicted by virtue of love, honesty and justice rather than battles and physical strength of an individual. As mentioned earlier, Marie de France performed for Eleanor of Aquitaine and Henry II of England, by the virtue that they were royal the poems had to be tailored to show bravery in virtues and ideals rather than wars and battles, which at the time were viewed to be barbaric and not befitting nobility In sir Gawain and the Green Knight, heroisms is also depicted as a virtues rather than physical strength. The main protagonist in the story, Sir Gawain who is the nephew of King Arthur and the youngest Knight accepts a challenge from the Green Knight who rides to Camelot on the New Years Day. According to Weston, (50), the challenge is for anyone to strike the Green Knight with his own arks and that the green knight will return the blow one year and one day after. Sir Gawain doesnt just strike the green knight, but severs his head on one strike, but the green knight picks up his head and reminds Gawain to meet him one year later at Green Chappell. Heroism in sir Gawain and the Green Knight, is demonstrated by the fact that sir Gawain honors his word and a year later rides to green Chappell to receive his dues, also the aspect of faithfulness and luck of greed is depicted in the story as being acts of heroism, during the long journey and on the brink of starvation, Sir Gawain encounters a beautiful castle and is hosted by lord Bertilak de Hautdesert and his beautiful wife, sir Gawain informs them of the task at hand to meet the green knight, but Bertilak informs Gawain that the Green chapel is only a mile away and that he should be Lord Bertilak guest. In the meantime each time Lord Bertilak went hunting lady Bertilak would try to seduce Gawain this went on for days, but Gawain would not yield, eventually she hands Gawain a green girdle. Gawain goes to meet the green knight at the chapel and finds him wa iting, Gawain bends and waits for the Green Knight to strike him, but due to fear, he flinches and Green Knight only makes a mark on Gawains neck on the third strike and reveals himself as Lord Bertilak de Hautdesert (Weston 56). Gawain is a hero because of virtues and not his strength, the ability to stick to his word and be faithful to lord Bertilak de Hautdesert saves him and returns to Camelot as a hero. Heaney, Seamus. Beowulf: a new verse translation. Reprint, New York: Norton Co., 2001. Print.Advertising Looking for essay on british literature? Let's see if we can help you! Get your first paper with 15% OFF Learn More Kline, T. Daniel. The medieval British literature handbook: Literature and cultural handbook. New York: Continuum International Publishing Group, 2009. Print. Marie, De France and Gallagher, Edward. The Lays of Marie de France. Upper Saddle River: Hackett Publishing, 2010. Print. Weston, Jessie Laidlay. Sir Gawain and the Green Knight: Dover Books on Literature Drama. New York: Courier Dover Publications, 2003. Print

Wednesday, February 19, 2020

Funding Streams in the Health and Social Care Sector Essay

Funding Streams in the Health and Social Care Sector - Essay Example There will be bids from consortia for approaches will be included in a wide range of client groups and innovation and sustainability beyond funding will be equally vital. A good number of evidence that may inform an evaluation of the approach will be used in supporting organization activity and are effectively self-sustaining in the long run. The proposal is supposed to be based on realistic level of resources that may help in the overall program. Evaluation of the funded program will be analyzed by the implementation group that will have the role of identifying and sharing lessons learned and the organizations that are successful in this round of bids will have the chance to learn from the operation of the program. The Program’s strategy is intended to ensure high quality, accessible advice that provides a key role in enabling informed choice and in supporting an individual’s pathway through support. On the other side, fund priorities include building the capacity of independent advice and support especially in areas where such kind of activities do not exist and addressing the support and information needs of all the user groups such as people providing care. Moreover, the fund will support the development of a range of advice and support services in relation to the relevant authorities and to evaluate the approaches taken within funded bids to support sustainability in the long run such as informing future commissioning strategies (Great Britain 2011, pp. 59-61).

Tuesday, February 4, 2020

Maine - A novel- J.courtney Sullivan Essay Example | Topics and Well Written Essays - 250 words

Maine - A novel- J.courtney Sullivan - Essay Example In this excerpt, like the other three women, Maggie is struggling with universal issues that are affecting women in this last century. As a result, she is forced to confront the real truths about themselves together with their relationships. Maggie is thirty-two years of age, and she is pregnant. However, she is still waiting for that perfect moment to break the news to her imperfect boyfriend (Sullivan, 430). However, when she got pregnant, her boyfriend backed away showing the continues string of inapproriate partners for the four women. Maggie can be located in her generation in the way she dressed. Sullivan writes, she appeared in â€Å"tiny tight dress in Lewinsky blue† (431). When Alice learns that Maggie is pregnant, she says, â€Å"Well, that’s, then,† (437). This shows her anger towards Maggie’s pregnancy. This contributes to the theme of love and anger in the story. As the story drifts towards the end, Kathleen says to Maggie, "Its going to be okay," (444) to which she responds, "It has to be"(446). This shows the existence of love between the women. This brings out the charms of Maggie’s adopted home in Brooklyn. Sullivan portrays three generations of women in the Kelleher’s family who take the guilt in their secrets of their private lives. In alternating accounts late spring and early summer, the female figures contradict and complement each other in surprising but contradictable manner. By the time the story comes to an end, the reader is also ready to leave the beach. Summarily, through Maggies, the story unveils the theme of sibling rivalry, irrational love, social climbing, alcoholism, and Catholic guilt all at the centre of this Keller family. Sullivan uses the four women to show their contrasting behaviours since they belong to different

Sunday, January 26, 2020

Rowhammer and Microarchitectural Attacks

Rowhammer and Microarchitectural Attacks Problem 1: Hardware Oriented Security and Trust Problem 2: Wireless Networking Problem 1 Introduction The analyzed paper deals with Side-Channel attacks on mobile devices, providing a thorough categorization based on several factors. Side-channel attacks aims to extract sensitive information taking advantage of apparently harmless information leakage of computing devices, both from the SW and HW point of view. Side-channel attacks are initially categorized as active or passive, depending on the level of influence and involvement the attack has on the system. The concept of Software and Hardware attacks are identified to separate attacks that exploit, respectively, logical and physical properties of a device. Also the distance of an attacker is a relevant element in the analysis of Side-channel attacks. The authors distinguish among Local, Vicinity and Remote Side Channel Attacks, depending on how close is the attacker to the attacked device. A comprehensive list of examples for every type of attacks is given, along with a constructive discussion on possible countermeasures. In this report, we will focus on the Rowhammer and Microarchitectural attacks that will be discussed in the following paragraphs. a) Rowhammer Attack As miniaturization of hardware architectures is pushed more and more, the density of memory cells of the DRAM drives the size of these cells to a dramatic reduction in dimensions. For the intrinsic properties of DRAMs, this leads to a decreases in the charge of single cells and could cause electromagnetic coupling effects between cells. Rowhammer attack takes advantage of this Hardware vulnerability. a.i) Principle The Rowhammer glitch takes place in a densely-populated cell hardware environment allowing an attacker to modify memory cells without directly accessing it. The aforementioned vulnerability in DRAM cells can be exploited by repeatedly accessing a certain physical memory location until a bit flips in an adjacent cell. A well-orchestrated Rowhammer attack could have devastating power, even getting to have root privileges. Rowhammer base its strength on a principle called Flip Feng Shui [2] where the attacker abuses the physical memory allocator to strike precise hardware locations and cause bits to flip in attacker-chosen sensitive data. Rowhammer can be either probabilistic [3] or deterministic [4]. The latter shows a greater impact as the lack of control of the first one could corrupt unintended data. The most effective Rowhammer attack is the double-sided Rowhammer [5], capable of having more flips in less time than other approaches. a.ii) Architecture The objective of Rowhammer attack is the DRAM. DRAM usually stores electric charges in an array of cells, typically implemented through a capacitor and an access transistor. Cells are then organized in rows. Thus memory cells inherently have a limited retention time and they have to be refreshed regularly in order to keep their data. From an OS point of view, a page frame is the smallest fixed-length adjacent block of physical memory that maps an OS memory page. From a DRAM point of view, a page frame is just a contiguous collection of memory cells with a fixed page size (usually 4KB). With this in mind, triggering bit flips through Rowhammer is basically a race against the DRAM internal memory refresh scheme to have enough memory accesses and cause sufficient disturbance to adjacent rows. a.iii) Instruction Set Architecture The Instruction Set Architecture (ISA) is a functional specification of a processor programming interface. It is used to abstract over microarchitecture implementation details (e.g. pipelines, issue slots and caches) that are functionally irrelevant to a programmer. Even though it is practically transparent, the microarchitecture incorporates a hidden state, which can be observed in several ways. To test whether Rowhammer can be exploited, a precise knowledge of memory cells dimension is crucial. In mobile devices, ARM processor represents the most widespread and used microprocessor. In [4] the authors determine the minimum memory access time that still results in bit flips by hammering 5MB of physical memory while increasing the time between two read operations by means of inserting NOP instructions. The rows are all initialized to a certain value, therefore all the changes are due to Rowhammer. Results show that up to 150 bit flips happen per minutes with around 150 ns read time. a.iv) Procedure The Rowhammer attack procedure is a combination of three main system primitives: P1. Fast Uncached Memory Access: Enable attackers to activate alternating rows in each bank fast enough to trigger the Rowhammer bug; P2. Physical Memory Massaging: The attacker tricks the victim component into storing security-sensitive data (e.g., a page table) in an attacker-chosen, vulnerable physical memory page. P3. Physical Memory Addressing: To perform double-sided Rowhammer, an attacker needs to repeatedly access specific physical memory pages. Mobile devices have Direct Memory Access (DMA) mechanisms that facilitates the implementation of P1 and P3. In particular, Android devices run ION, a DMA that allows user unprivileged apps to access uncached physically contiguous memory. To enforce P2 the attacker tricks the physical memory allocator built in Linux (buddy allocator) so as to partition the memory in a predictable way. Accurately selecting the dimensions of memory chunks to allocate, memory cells can be exhausted through Phys Feng Shui. Once the position of Page Table Pages (PTPs) and Page Table Entries (PTEs) is indirectly known, double-sided Rowhammer is performed. Once the desired flip triggered, write access is gained to the page table by mapping into the attacker address space. Modifying one of the attacker PTPs, any page in physical memory can be accessed, including kernel memory. b) Microarchitectural attack  ­The evolution of hardware architecture lead to a wide use of cache memories. Having several levels of cache between a CPU and the main memory, helps optimizing the memory access time with respect to the clock frequency. Microarchitectural attacks take advantage of the timing behavior of caches (e.g. execution times, memory accesses) to read into sensitive information. In [6] a comprehensive survey that presents microarchitectural attacks is given. b.i) Principle Microarchitectural attacks are based on different cache exploitations. Among them, three main methods are identified: Prime + Probe: The attacker fills one or more sets of the cache with its own lines. Once the victim has executed, the attacker accesses its previously-loaded lines, to probe if any were evicted showing the victim have modified an address mapping the same set. Flush + Reload: Its the inverse of Prime+Probe where the attacker first flushes a shared line of interest. Once the victim has executed, the attacker then reloads the evicted line by touching it, measuring the time taken. A fast reload indicates that the victim touched this line (reloading it), while a slow reload indicates that it didnt. Evict + Time: The attacker first tricks the victim to run, through the preload of its working set, and establish a baseline execution time. In a second step the attacker then eliminates a line and runs the victim again. The difference in execution time indicates that the analyzed line was accessed. All microarchitectural attacks are a combination of those previously explained principles. Another noteworthy approach is causing Denial of Service (DoS) saturating the lower-level cache bus [7]. .b.ii) Architecture As mentioned before, microarchitectural attacks objective is the cache. Caches are organized into lines. A cache line holds a block of adjacent bytes that are taken from memory. Cache are further organized in levels. Each level has a different size and is carefully selected to balance service time to the next highest (smaller in dimension therefore faster) level. Caches can enforce either Virtual or Physical addressing. In Virtual addressing, L1 cache level stores the index of virtual-to-physical addresses. .b.iii) Instruction Set Architecture The inference process of the internal state of the cache is a key parameter to perform devastating microarchitectural attacks. Analyzing the ISA of a cache can provide an attacker with useful information about the hardware structure. Several different states can be exploited and are briefly summarized here: Thread-shared State: cache stores information that are shared between threads. Accessing them could lead to performance degradation of the involved threads. Core-shared state: Analyzing L1 and L2 cache contention usage between competing threads, it is possible to infer the encryption keys for algorithm used in internal communication (e.g. RSA, AES). Package-shared State: Running a program concurrently in different cores residing in the same package, could lead to the saturation of that packages last-level cache (LLC). The saturation affects all the lower levels, exposing sensitive data. Numa-shared State: Memory controllers memory in multi-core systems are exploited to enforce DoS attacks. .b.iv) Procedure A plethora of attacks are presented in [6], therefore the procedure of the Flush + Reload for Android systems using ARM processors [8] is discussed. The most powerful methods to perform Flush + Reload is to use the Linux System Call clflush. However it is provided by the OS on x86 systems, on mobile devices using ARM this function is not available. A less powerful version of it is clearcache and is used in [8]. When the attack starts, the service component inside the attacker app creates a new thread, which calls into its native component to conduct Flush-Reload operations in the background: Flush: The attacker invokes clearcache to flush a function in the code section of this shared line. Flush-Reload interval: The attacker waits for a fixed time for the victim to execute the function. Reload: The attacker executes the function and measures the time of execution. With a small execution time, the function has been executed (from L2 cache) by some other apps (possibly the victims). In [8] the authors show that this method is capable of detecting hardware events (touchscreen interrupts, credit card scanning) and also tracing software executions paths. c) Rowhammer vs Microarchitectural attack Following the categorization used in [1], both Rowhammer and Microarchitectural attacks are active software attacks that exploits physical properties of the victim device. In particular Rowhammer uses the coupling effect of DRAM cells while Microarchitectural attacks gather sensitive information through the analysis of cache timing. The two attacks act at two different levels: while Rowhammer needs to work fast on an uncached DRAM, Microarchitectural attack objective are cache memories that are usually SRAM. Both of them can be applied to desktop and to mobile OS [4][8], as well as cloud environments. c) Mobile vs Desktop attacks Mobile devices are inherently more vulnerable than Desktop computers. Their portability and close integration with everyday life make them more available to attackers. Moreover, apps are way more easy to install on mobile devices and general carelessness helps hackers in installing malicious software. Also, with respect to desktop computers, mobile phones have several sensors that can be exploited to gather information about users behavior. But from a OS point of view, mobile OS are way more limited than Desktop OS. Specifically, Rowhammer suffers from the limited subset of features available in desktop environments (e.g. no support for huge pages, memory deduplication, MMU paravirtualization). Same limitations happens in Microarchitectural attacks for ARM , where clflush function to perform Flush + Reload is not supported. 2) NAND Mirroring NAND mirroring is categorized in [1] as an active local Side Channel attack that exploits physical properties out of a device chip. In particular, in [13] a NAND mirroring attack is performed on an iPhone 5c. The security of Apple iPhone 5c became an objective of study after FBI recovered such mobile device from a terrorist suspect in December 2015. As FBI was unable to retrieve data, NAND mirroring was suggested by Apple technology specialists as an optimal way to gain unlimited passcode attempts so as to bruteforce it. As the encryption key is not accessible from runtime code and its hardcoded in the CPU, it is impossible to brute-force the Passcode key without the getting at the hardware level. In iPhones such memory is a NAND flash memory. In NAND memories the cells are connected in series which reduces the cell size, but increases the number of faulty cells. For this reason, external error correction strategies are required. To help with that, NAND memory allocates additional sp ace for error correction data. In [13] the authors desoldered the NAND memory and mirrored it on a backup file. Although this method seems promising, several challenges were encountered by the authors, who had to balance some electrical anomalies with additional circuitry and also mechanically plug in a PCB at every attempt of bruteforcing the iPhone code. Such method could be applied to Desktop Computers, but the complexity of NAND memories would be way higher and it may unfeasible, in terms of time and complexity, to perform such attack. Countermeasures Side-channel attacks are discovered and presented to the scientific world on a daily basis and suitable defense mechanisms are often not yet implemented or cannot be simply deployed. Even though countermeasures are being studied, it looks like a race between attackers and system engineers trying to make systems more secure and reliable. 3.a) Rowhammer Attack Countermeasures against Rowhammer have already been thoroughly explored, but not many are actually applicable in the mobile context. Powerful functions as CLFLUSH [9] and pagemap [10] have been disabled for users apps, but Rowhammer can still be performed through JavaScript. Furthermore, analyzing the cache hits and miss could raise a flag of alarm, but methods such as [4] dont cause any miss. Error correcting codes arent even that efficient in correcting bit flips. Most hardware vendors doubled the DRAM refresh rate, but results in [11] show that refresh rate would need to be improved by 8 times. Moreover, the power consumption would increase, making this solution not suitable for mobile devices. In Android devices Rowhammer attacks, the biggest threat is still user apps being able to access ION. Google is developing mechanisms so as to avoid it to happen in a malicious way. One solution could be to isolate ION regions controlled by user apps from kernel memory, in order to avoid ad jacent regions. But even in the absence of ION an attacker could force the buddy allocator to reserve memory in kernel memory zones by occupying all the memory available for users apps. Prevention of memory exhaustion need to be considered to avoid Rowhammer countermeasures workarounds. 3.b) Microarchitectural Attack As the final goal of microarchitectural attack is deciphering cryptographic codes (e.g. AES), a straightforward approach to protect them would be to avoid having tight data-dependencies (e.g sequence of cache line accesses or branches must not depend on data). If they depend on private data, the sequence, the program is destined to leak information through the cache. The constant-time implementation of modular exponentiation approach [12] represents a good way to fight data dependency. These are more general rules to follow, whether to combat specific attacks such as Flush + Reload in mobile devices with ARM [8]. Disabling the system interfaces to flush the instruction caches, the Flush-Reload side channels can be removed entirely from ARM- based devices, but feasibility and security of this method havent been studied yet. Also, by removing system calls to have accurate time from Android could mitigate all timing side channels. Another way to fight Flush + Reload would be by preventing physical memory sharing between apps, but that would cause the memory footprint to expand and therefore exposing the system to other Sidechannel attacks. Problem 2 Protocol Design The proposed solution for Problem 1 is represented in Figure 1. To solve this problem, four moments in which the Path-centric channel assignment algorithm from [14] are identified: : B receives a packet on its Channel 1 and, as an interferer is acting on Channel 1 on node A, B cant transmit. B1 is the active subnode, B2 and B3 are inactive subnodes. : B switches from Channel 1 to Channel 2 (total cost: 3), and forward the packet to A through Channel 2 (total cost: 3+6=9). B2 is the active subnode, B1 and B3 are inactive subnodes. A2 is the active subnode, A1 and A3 are inactive subnodes. : A can either transmit on Channel 2 and Channel 3, but transmitting on Channel 2 is more expensive, so it switches to Channel 3 (total cost: 9+3=12). A3 is the active subnode, A1 and A2 are inactive subnodes; : A send the packet at C through Channel 3 (total cost: 12+2=14). Network Applications In our K-out-of-N system we are interested in understanding how much is a probability of getting errors in sensing from N sensor, where K represent a threshold for accepting a reliable measurement. This reasoning follows the binomial distribution: In our case at each node, errors can be induced by a false measurement (with probability ) or by channel flipping a bit during the over-the-air time (with probability ). Therefore for our N-out-of-K nodes system we have: Assuming that and are independent, the final probability of having an erroneous detection is a linear combination of the two: For completion, the probability of a successful measurement and transmission is . Network Standards Spectrum scarcity is a widely known problem in the world of wireless communications. The explosive wireless traffic growth pushes academia and industry to research novel solutions to this problem. Deploying LTE in unlicensed spectrum brings up the conflict problem of LTE-WiFi coexistence. This conflict can be analyzed with a close look at 802.11 MAC level. In Figure 2, a comparison between WLAN MAC layer and what is casually called MAC in LTE is depicted [19]. WiFi 802.11 uses CSMA/CA to regulate accesses in MAC layer. In CSMA, a node senses the traffic before transmitting over the channel. If a carrier signal is sensed in the channel, the node waits until its free. In particular, in CSMA/CA the backoff time of a node is exponential. In LTE, multiple access is handled through TDMA (Time Division Multiple Access) meaning that all accesses to the channel are scheduled. Historically LTE has been developed for environments with little interference, while WiFi combats interference in ISM with CSMA. Using them in the same spectrum would see LTE dominating over WiFi, causing sever performance degradation in both the cases. Several solutions has been proposed and implemented in the past years. Qualcomm [15] and Huawei [16] proposed a separation in time and frequency domain. In [17] a Technology Independent Multiple-Output antenna approach is presented so as to clean interfered 802.11 signals. This method was made more robust in [18] but still they relied on the fact that at least one signal from the two technologies had a clear reference. Traffic demands analysis could help mitigate the performance drop due to interference, but even with an accurate demand estimation, only one can be active at a certain time and frequency, limiting the overall throughput. When interference is high, packet transmission is corrupted and error correction strategies are needed. In WiFi, standard Forward Error Correction (FEC) is used. In FEC, a redundancy is added to the transmitted packet, so as a receiver can detect and eventually correct the wrong received bits. On the other hand, LTE uses HARQ (Hybrid-Automated Repeat reQuest) which is a combination of FEC and ARQ. In the standard implementation of ARQ, redundancy bits are embedded in the packets for error detection. When a corrupted packet is received, the receiver request a new packet to the transmitter. In HARQ, FEC codes are encoded in the packet, so as the receiver can directly correct wrong bits, when a known subset of errors is detected. If an uncorrectable error happens, the ARQ method is used to request a new packet. Hybrid ARQ performs better than ARQ in low signal conditions, but leads to an unfavorable throughput when the signal is good. To better see this interference behavior, a small simulation has been performed using ns3, in particular the LAA-WiFi-coexistence library [20]. The scenario was built using two cells whose radio coverage overlaps. The technologies used are LTE Licensed Assisted Access (LAA) operating on EARFCN 255444 (5.180 GHz), and Wi-Fi 802.11n operating on channel 36 (5.180 GHz). Two base station positioned at 20 mt distance from another, and they both have one user connected to them at a distance of 10 mt. Both BS are connected to a backhaul client node that originates UDP in the downlink direction from client to UE(s). In Figure 3(a) and Figure 3(b), we see how the throughput and the number of packets received by the WiFi BS varies when the two BSs coverage area overlaps and when they are isolated (e.g. their distance is 10 Km). Other scenarios were tested: Figure 4 (a) represent the scenario of two WiFi BSs and Figure 4(b) two LTE BSs. It is possible to see the behavior of the two technologies . Table 1 Throughput A Throughput B Packet loss A Packet loss B Distant BSs Figure 3(a) 73.78 Mbps 77.55 Mbps 4.6% 0% Interfering BSs Figure 3(b) 73.62 Mbps 4.95 Mbps 4.8% 93% Two WiFi BSsFigure 4(a) 53.45 Mbps 54.41 Mbps 27% 25% Two LTE BSsFigure 4 (b) 30.88 Mbps 30.4 Mbps 60% 61% In Figure 4(a) we can see how the channel is split between the two BSs and the Carrier Sensing Multiple Access keeps a high throughput and a low packet loss. In Figure 4(b) we can see how the interference between the two LTE cells affects the throughput and gives a high packetloss. In Table 1 results from simulations are summarized. References [1] R. Spreitzer, V. Moonsamy, T. Korak, S. Mangard. Systematic Classification of Side-Channel Attacks on Mobile Devices ArXiv2016 [2] K. Razavi, B. Gras, E. Bosman, B. Preneel, C. Giurida, and H. Bos. Flip Feng Shui: Hammering a Needle in the Software Stack. In Proceedings of the 25th USENIX Security Symposium, 2016. [3] D. Gruss, C. Maurice, and S. Mangard. Rowhammer.js: A Remote Software-Induced Fault Attack in JavaScript. In Proceedings of the 13th Conference on Detection of Intrusions and Malware Vulnerability Assessment (DIMVA), 2016. [4] V. van der Veen, Y. Fratantonio, M. Lindorfer, D. Gruss, C. Maurice, G. Vigna, H. Bos, K. Razavi, and C. Giuffrida, Drammer: Deterministic Rowhammer Attacks on Mobile Platforms, in Conference on Computer and Communications Security CCS 2016. ACM, 2016, pp. 1675-1689. [5] Z. B. Aweke, S. F. Yitbarek, R. Qiao, R. Das, M. Hicks, Y. Oren, and T. Austin. ANVIL: Software-Based Protection Against Next-Generation Rowhammer Attacks. In Proceedings of the 21st ACM International Conference on Architectural Support for Programming Languages and Operating Systems (ASPLOS), 2016. [6] Ge, Q., Yarom, Y., Cock, D., Heiser, G. (2016).A survey of microarchitectural timing attacks and countermeasures on contemporary hardware. Journal of Cryptographic Engineering [7] Dong HyukWoo and Hsien-Hsin S. Lee. Analyzing performance vulnerability due to resource denial of service attack on chip multiprocessors. In Workshop on Chip Multiprocessor Memory Systems and Interconnects, Phoenix, AZ, US, 2007. [8] X. Zhang, Y. Xiao, and Y. Zhang, Return-Oriented Flush-Reload Side Channels on ARM and Their Implications for Android Devices in Conference on Computer and Communications Security CCS 2016. ACM, 2016, pp. 858-870. [9] M. Seaborn and T. Dullien. Exploiting the DRAM Rowhammer Bug to Gain Kernel Privileges. In Black Hat USA (BH-US), 2015. [10] M. Salyzyn. AOSP Commit 0549ddb9: UPSTREAM: pagemap: do not leak physical addresses to non-privileged userspace. http://goo.gl/Qye2MN,November 2015. [11] Y. Kim, R. Daly, J. Kim, C. Fallin, J. H. Lee, D. Lee, C. Wilkerson, K. Lai, and O. Mutlu. Flipping Bits in Memory Without Accessing Them: An Experimental Study of DRAM Disturbance Errors. In Proceedings of the 41st International Symposium on Computer Architecture (ISCA), 2014. [12] Ernie Brickell. Technologies to improve platform security. Workshop on Cryptographic Hardware and Embedded Systems11 Invited Talk, September 2011. [13] S. Skorobogatov, The Bumpy Road Towards iPhone 5c NAND Mirroring, arXiv ePrint Archive, Report 1609.04327, 2016. [14] Xin, Chunsheng, Liangping Ma, and Chien-Chung Shen. A path-centric channel assignment framework for cognitive radio wireless networks Mobile Networks and Applications 13.5 (2008): 463-476. [15] Qualcomm wants LTE deployed in unlicensed spectrum. http://www.fiercewireless.com/story/qualcomm-wants-lte-deployed-unlicen% sed-spectrum/2013-11-21 [16] Huawei U-LTE solution creates new market opportunities for mobile operators. http://www.huawei.com/ilink/en/about-huawei/newsroom/ press-release/HW 3%27768. [17] S. Gollakota, F. Adib, D. Katabi, and S. Seshan. Clearing the RF smog: making 802.11 robust to cross-technology interference. In Proc. of ACM SIGCOMM, 2011. [18] Y. Yubo, Y. Panlong, L. Xiangyang, T. Yue, Z. Lan, and Y. Lizhao. ZIMO: building cross-technology MIMO to harmonize Zigbee smog with WiFi flash without intervention. In Proc. of MobiCom, 2013. [19] Long-Term Evolution Protocol: How the Standard Impacts Media Access Control Tim Godfrey WMSG Advanced Technology, http://www.nxp.com/files-static/training_presentation/TP_LTE_PHY_MAC.pdf [20] https://www.nsnam.org/wiki/LAA-WiFi-Coexistence

Saturday, January 18, 2020

Ap Psychology Fall Term Project

AP Psychology Fall Term Project Introduction I am more interested in the abstract and philosophical aspects rather than the more concrete biological aspects of psychology. The topic that interested me the most so far this year and the topic that I continued to research was the topic of morality. I didn’t have a specific question I wanted to address but as I read some articles about people who were institutionalized for violently expressing psychopathic personality traits, I came across an article that asked a question of its own.The article brought up the idea that traits of psychopathy including ruthlessness, charm, mindfulness, focus, fearlessness, and action can be beneficial to the individual. From this idea, the question I sought to answer was â€Å"If we all take on typically immoral psychopathic tendencies, are they no longer immoral? † Summary The article I read came from Scientific American adapted from the non-fiction book The Wisdom of Psychopaths: What Saint s, Spies, and Serial Killers Can Teach Us about Success by Kevin Dutton. The main question posed by Dutton is: Can the typical traits of a psychopath benefit people at certain points in their lives?The article is more of an interview with some patients at Broadmoor, â€Å"the best-known high-security psychiatric hospital in England† and an observation rather than a study with measurements and variables. However, applying knowledge of Kohlberg, Brofenbrenner, and Gillian’s theories make the article even more interesting. In the article, Dutton discusses the inmates’ solutions to problems similar to that of the Heinz dilemma, psychopathy and the brain, and a relation to psychopathic traits to religion and happiness.If what he discusses were put into terms of variables, the independent variable could be expression of psychopathic traits and the dependent variable could be anything the traits effect from happiness to inner or universal morality. Discussion In the ar ticle, the ideas of the psychopaths can be looked at and evaluated using both Kohlberg and Brofenbrenner’s theories on moral development. In the article Dutton asks one of the inmates a hypothetical question. An old woman moves out of her house to live with her daughter and son-in-law.The house is in an up and coming neighborhood and she can get a good price if she sold it. The only problem is the tenant who doesn’t want to move out. How do you get the tenant to leave? The first thing the psychopath said was â€Å"I’m presuming we’re not talking violence here† indicating that psychopaths do have a sense of the Level II conventional morality described by Kohlberg. The psychopath recognizes that violence is typically punished and looked down upon by law and society, putting the psychopath into at least Stage 4 of Kohlberg’s theory of moral development.Essentially the psychopath solves the problem by saying that someone should pretend to be som eone from the health department and tell the tenant that the house is not safe to live in and he must leave as soon as he can. He doesn’t explain his reasoning but most psychopaths are concerned with one thing only: getting the job done. However, the article doesn’t go into why or how the psychopath determined this was the best way to remove the tenant.If the psychopath figured the action would lead to reward (getting the tenant out) and that is the only consequence, he would be in Stage 1 of Kohlberg’s theory and orientation 1of Bronfenbrenner’s theory. On the other end of the spectrum, if the psychopath figured that if the house got sold and the old woman and her daughter and son-in-law could live comfortably, that the expulsion of the tenant (whether he became homeless or even finds another place to stay) would be the greatest good for the greatest number, putting him in Stage 5 of Kohlberg’s theory.This would be orientation 4 of Bronfenbrennerà ¢â‚¬â„¢s theory called objectively oriented morality in which the standing goals of the group override that of the individual. As the conversation continues, the discussion turns to worrying about the future affecting actions in the present. The psychopaths discuss the idea that there’s no use in getting your mind wrapped in what might happen when everything in the present is perfectly fine and that you shouldn’t let your brain get ahead of you. Do in the moment what makes you happy. Dutton describes this as mindfulness.Dutton brings up the fact that embracing the present is something that psychopathy and schools of spiritual enlightenment have in common. When it comes to psychology, Dutton brings up a â€Å"mindfulness-based cognitive-behavior therapy program for sufferers of anxiety and depression. † Surely, mindfulness and living in the present has its benefits but ignoring the future can produce dangerous consequences as well. Since some stages of morality a re based on self satisfaction, others the law and religion, and further the good of society, I have answered my question â€Å"If we all take on typically immoral psychopathic tendencies, are hey no longer immoral? † The answer I came up with is, â€Å"it depends. † The reason â€Å"it depends† is because, well, it does. Anyone can have psychopathic traits of mindfulness, ruthlessness, action, charming, and fearlessness; it’s just about how we use them. Sure, Dutton suggests these traits can lead to happiness and success, but in the right amount and for the right reasons. What we consider the â€Å"right reasons† and â€Å"right amount† is also based on our own levels of morality. If everyone was charming, fearless, ruthless, and mindful, we would all be doing what we could to get ahead and be happy.If doing what is necessary to be happy and get ahead became a universally moral idea, then sure, there wouldn’t be a problem with psychop aths, liars, and cheaters. But in the world in which we live, where we all have our own different ideas of good and bad with exceptions and loopholes included, under the â€Å"right† circumstances, these traits are acceptable and useful, but at the â€Å"wrong† times they can be damaging and violating. Should we all just become psychopaths? I guess it just depends. Citation Dutton, K. (2013, January). Wisdom from Psychopaths? [Electronic version]. Scientific American.

Friday, January 10, 2020

Literature as a Looking Glass

Perhaps it is the aim of every storyteller to leave their reader a little changed after having read the tales they so carefully weave.   But how many authors can actually achieve this? Leaving their audience with a story that broadens the mind, asks deep questions, and probes into the way we work is not easily done.   The ability to move us from one plane to another is what distinguishes a really great writer from a storyteller.   For many, Stephen King is such an author.   Some may say even more so because of the use of his genre of the fantastical, the horrific and the gruesome. Exploring the darker parts of our psyches, and our everyday lives, he manages to lead us along the path to contemplate difficult social questions. Always leaving them open for us to determine the answers for ourselves.In a comparison of his two works, The Long Green Mile and Hearts of Atlantis, we can explore his use of the fantastical as an opportunity to raise thought provoking social questions.   Although both books, also interestingly both written as a series, are very different in nature, they share the common theme of finding the extraordinary in ordinary life.   Each book finds the hero that seems to hide in everyday circumstances while at the same time forcing us to look at several of the factors that shape our lives, for the good or the bad. As mentioned by Jonathan Davis in his work, Stephen King’s America, â€Å"While some of his stories focus more on one area than others, a close reading of his works will often show that King seldom fails to include a wide view of American society.† (Davis)The Long Green Mile is a prime example of King’s use of storytelling as social commentary.   In the book the main characters are themselves symbols of the society in which we live.   John Coffey, and innocent man sent to death row for a crime he didn’t commit. Is it because he is simple, or because he is black? As Sharon Russell states in her c ritical review, Revisiting Stephen King , â€Å"While Coffey dominates the action, he remains an enigma, a symbol of a good beyond understanding.† (Russell)And his mysterious gift to heal is starkly contrasted with William Wharton’s ability to destroy.   Just as Coffey is the symbol for good, so is Wharton the symbol for evil.Moreover, the underlying theme that resonates throughout the book is just that; the nature of good and evil. And Stephen King shows us how that battle rages in many arenas of our lives. One obvious question is that of racism. Was Coffey found guilty because he was black? Another character in the story, a white business man, was released from a murder he obviously committed. There was nothing to point to Coffey but the fact that he was found with the girls. Was racism a factor?Also, the question of the death penalty raises its head several times. Delacroix, a horrible man, suffered death in the electric chair. However, the brine filled sponge tha t was supposed to make the electrocution quick and painless was omitted purposefully by one of the jailers. This resulted in a horrific and torturous death by Delacroix.   Was his suffering justifiable?Delving a little more deeply we probe the seemingly senseless death of Janice who had just escaped death by the miraculous hands of Coffey.   After all the trouble and the wondrous miracle that saved her life, to die in a bus accident leaves lingering questions of human justice versus divine justice.Similarly, in Hearts of Atlantis   King dances the fine line between fantasy and reality, although in a different way.   Although some of the characters are recurring, we are able to see them forming the opinions and beliefs that will be the basis of their actions in the future. Also, again King explores the realm and power of childhood.   In The Long Green Mile Coffey is used and explored as childlike and also, interestingly, he is the one that has the mystical and unquestioned healing power.   In Hearts of Atlantis   we see the children as they are and watch their struggle with reality and fantasy defines them.Those transitional moments are very apparent in the first story of Bobby and Carol.   Bobby was an everyday hero, Stephen King style. The ordinary fabric of society, hiding hero’s in every thread.   However, King goes one step further by reintroducing the few key characters throughout a string of seemingly unrelated stories.   By doing this he shows us the connectivity of individuals. How the actions we make today have huge impacts on others and shape their lives. Bobby’s bravery inspired Carol’s courage to stand up for what she believed later in life.By looking closely at the lives of the characters we could see how the past could have drastic effects on the future. Although with the case of Carol it empowers her, it is not the same for everyone. This is illustrated in the story, â€Å"Blind Willie†.   Bill r elives each day trying to resolve the regret for his past actions. We see the old baseball glove of Bobby’s that Blind Willie uses to collect the money he earns as a broken Vietnam veteran while his wife and family believe him to be a successful business man busy at the office.   Willie tries to find answers by living a double life.Moreover, King uses the opportunity to stir up a social commentary on the effects the Vietnam War had on people specifically and then society as a whole.   He uses the series of stories to look at different aspects of reaction. From the earliest stages, when war is just playing in the background, as in the case with Bobby in â€Å"Low Men in Yellow Coats† and then also with young adults drifting in and out of adulthood and drafting such as was portrayed in â€Å"Hearts in Atlantis†.Although it seems to be a simple peek into the issues that concern college aged kids trying to leap into adulthood, the story sells its moral in the en d, as stated by Russell, â€Å"The story ends with an incident long after the main events—a reunion between Pete and one of his college friends. No matter what happened, they both agree that they tried during that period. They were not the big heroes, but they did something—just as Bobby saved Carol but failed with Ted. King suggests that any positive action is important even if it is not truly heroic.† (Russell)Davis, Johnathan. Stephen king's America. Bowling Green: Bowling Green State University, 1994.Russell, Sharon. Revisiting Stephen King. Wesport, CT: Greenwood Press, 2002.Davis, Johnathan. Stephen king's America. Bowling Green: Bowling Green State University, 1994.Russell, Sharon. Revisiting Stephen King. Wesport, CT: Greenwood Press, 2002.In this way, everyone has the opportunity to be a type of hero, no matter how small the action, the effects can be long lasting.While an extensive look at any author’s works reveals a repeating and recurring the me or message that appears to be central in their writing, it is Stephen King’s use of his particular genre that continually draws in his readers again and again.   The parallel of the darker side of humanity with the fantastical opens windows to explore and question the reasons we think, act and believe as we do.   Perhaps it is just that use of the darker and less explored side of humanity that holds such a fascination.Russell   comments,   â€Å"The ongoing battle in King’s fantastic universe to follow the beam and keep the world from falling apart is mirrored by later actions in the real world.†   So, in addition to his use of the genre to explore our social fabric,   his consistent use of our interconnectedness and how the past affects the present are major recurring themes.   By playing on our fears and opening up our minds to the impossible, we are able to look openly at issues that affect our lives without judgment, and perhaps emerge a bet ter person.