Henry Ford Was A Genius In Many Aspects Of Our Everyday Life. He Chang

Henry Ford was a genius in many aspects of our everyday life. He changed industry, production, and everybody's lifestyle. Many people know about him inventing some of the first automobiles, but what came out of it for America was a new encouragement for technology and an easier lifestyle for the average American. Also Henry Ford has changed the perspective of industries around the world. His invention of the assembly line and his five-dollar a day wage for the average worker brought about a total new change in factories. Ford's style and ingenuity helped America to be more prosperous and created a large amount of opulence for America in the early 1900's, all because of one man's creativity and determination to achieve a dream that would help out the common man and the entire world. Henry Ford was born on July 30, 1863, on a farm a few miles from Detroit. As a boy Henry was very creative and liked to work with tools. However, he hated doing chores and he always wanted to make things easier to do in life. This would be Henry's motto in life, always wanted to make things easier to do in life, at home or work. Ford was so creative that in 1893, he built his first engine and in 1896, he completed what he called the quadricycle, which ran for several years and sold it for $200. Ford had his second car finished in 1898 which was lighter and stronger than most cars around then. Soon enough many automobile companies were looking for somebody like Ford to help get their company going. However, Ford would go into automobile racing and then build his own car company. Ford's years in automobile racing was his way to improve the car and a chance to test it under competition. Soon though, he would get out of racing by a tough minded and ambitious James Couzens, who developed plans for a car company. Couzens was able to start out the company with $28,000 in cash, and $21,000 in notes. The Ford Motor Company came out with the model A, the model B, and the model K in their beginning years. However, most of these cars were too expensive for the common man. So Ford decided that he would make a car that was affordable to the ordinary worker. For a few years, Ford and his technicians began building their next and most important car in history. In 1908, Ford brought out for the first time the Model T. It was an ugly car, seven feet high with false doors and a crank. Even though it was ugly and simple, it was modern and affordable. Actually, it was ahead of it's time. The car could generate it's own electricity for ignition and it had a planetary transmission which allowed women and children to drive it. It was easy to operate and had the most efficient gasoline gauge of it's time. The greatest thing that came out from the Model T, was it's influence in all of America. Since the Model T was the first affordable car, which reached a low of only $260 in 1925, it allowed the average American to own a car now. One thing the Model T helped in was the improvement of the roads. With more people out on the roads, many roads were now being paved, and highways and bridges were being built for cars. Also farmers saw the Model T effective, soon the rural population was brought into the mainstream of technology. It was such a popular car, that over fifteen million were sold all over the world. However, the most important thing the Model T did, was it's impact on connecting the people of America. Bridges, roads, and highways were starting to be built for automobiles. Women were starting to leave the house now more because the Model T was easy to drive. Families could now go on trips and see America. Access to places was easier now, which led to the building of more stores, restaurants, and companies. This car was such a great impact, that the lifestyle we know today was created a lot by one automobile. The Model T, was the most affordable car of it's

American Protest Literature

American Protest Literature The literary work that will be focused on will be â€Å"the fire next time† which is a book written by James Baldwin in 1963.Advertising We will write a custom assessment sample on American Protest Literature specifically for you for only $16.05 $11/page Learn More The book contains two essays which include â€Å"My Dungeon Shook-Letter to my Nephew on the One Hundredth Anniversary Emancipation† which discusses the central role of race in American history written in the form of a letter addressed to Baldwin’s 14-year old nephew and the second â€Å"Down at The Cross- Letter from a Region of My Mind† which deals with the relationship between race and religion based on Baldwin’s personal experiences with Christianity and Islam when he was young. These two essays were used by Baldwin to provide a more extensive meaning of the Negro Problem or racial tensions that existed in America during the 1960s. The purpose of this assessm ent will be to determine whether this book qualifies to be identified as a piece of protest literature and the various areas the author has chosen which represent protest literature. American protest literature is referred to as a form of literary work that has been written to create some form of awareness within a society that has been subjected to various forms of injustice. This type of literature is meant to highlight the struggle of these communities so that they can be able to overcome the atrocities and abuses they have been subjected to over certain durations of time. Baldwin’s book qualifies for protest literature because it addresses issues to do with American history and also Christianity and the Islamic faith. The first few pages of the book focus on the first essay where Baldwin writes a dedicatory letter to his 14 year old nephew and namesake James. Baldwin basically advises his nephew on how to deal with the racist society of America in which he was born.Advert ising Looking for assessment on american literature? Let's see if we can help you! Get your first paper with 15% OFF Learn More The letter basically offers some form of evaluation on the situation of blacks in America after the Emancipation Proclamation was signed to give the African American society freedom from the white oppressors. Baldwin basically addresses his nephew by pointing out that much of the difficulties the Negro community experienced in the white dominant country were known to the various members of the black society. The letter represents some form of protest writing where he tells his nephew that he believes the Negros (as they were known then) had to take the high road when showing the white Americans how to live a good and proper life (Baldwin 4-6). In his letter, Baldwin talks about the Negro community of America at times terming them as ignorant and also innocent to the actions of the white American society. He generally describes this c ommunity to be one that is strong to the various adversities and brutalities inflicted on them by the white Americans. He also describes them as having an unassailable resilience since they were able to overcome the most terrifying odds to achieve freedom from slavery and racial discrimination which had been directed towards them for a considerable length of time by the white society. This letter is basically meant to reaffirm the importance of the Negro community to Baldwin’s nephew despite the actions of the various members of the community (Baldwin 6-8). Baldwin (9) tells his nephew not to lose faith in his community as a result of their actions against those who sought to defeat their existence in the white society. In the last part of the essay, Baldwin (8-10) talks about how the African American community has been able to overcome the imposed values and belief systems of the white society where they have for example defeated the intention of spelling their names properl y and also practising their religion.Advertising We will write a custom assessment sample on American Protest Literature specifically for you for only $16.05 $11/page Learn More This reflects protest writing as the writer speaks of how the Negro community was empowered to refuse any form of racial discrimination and slavery imposed on them by the white man. He addresses the aspect of integration by saying that the white society members should accept them as they are and stop fleeing from the reality of the social situation in America (10). In the second part of the book titled â€Å"Down at the Cross† Baldwin focuses on religious and race matters by assessing his own background as a Christian minister during his teenage years. In the very first parts of this section, he recounts his religious experiences as a fourteen year old boy by offering an insight into the religion of the Negros (16). He talks about how he joined the church to escape from the b rutality and atrocities committed against his fellow brothers because the church offered him some apparent form of safety from the dangers that were in the street. His escape to the church was also attributed to the moral decay that was being experienced in the Black community of that time. He describes how prostitution had become a problem especially in the place called the Avenue where all the socially immoral members of the black community headed to engage in immoral behaviour (Baldwin 17). In the second part of the â€Å"Down at the Cross† essay, Baldwin dismisses religion especially that practiced by the African Americans to be one that is not taken seriously because they have failed to live up to the ideals that were taught by Jesus in the Bible. He views it to be more of an escapist religion where the African Americans engage in worship to demonstrate their innocence to the racial discrimination they are being subjected to. The Christian Negros failed to practice the p rinciples of faith, hope, love and charity especially when they began to castigate the other members of society who did not observe Christian practices. Their religion was more dramatic and unreserved when compared to that of the white American society (Baldwin 15-22).Advertising Looking for assessment on american literature? Let's see if we can help you! Get your first paper with 15% OFF Learn More Baldwin also talks about the Muslim movement which was beginning to rise within the African American community where he tries to come to terms with the religion of Islam, Prophet Mohammed and other important religious leaders of the Islamic religion (46). Baldwin in his assessment of the Islamic faith focused on Elijah Muhammad (47) who was an African American religious leader during the 1960s. Muhammad led the Nation of Islam from 1934 to 1975 where he taught his African American followers on the ways of Islam. Elijah viewed Christianity as the white man’s rationale for oppressing the Negros because the basic foundation of the African American religion was founded on white Christianity (Baldwin 44-50). Baldwin criticised Elijah’s teachings because they were mostly centred on racial hatred that was not any better from the racial hatred the white people directed towards the African American society. Elijah saw the Christian religion as an extension of white rule and rac ial discrimination against black people. He believed that God was black and that he should have been addressed as Allah, the chosen one who has been selected to end the white devil’s domination in the African American society (Baldwin 49). Baldwin, James. The fire next time. New York: Vintage Books, 1993.

Functional Relationships Assignment Example | Topics and Well Written Essays - 500 words

Functional Relationships - Assignment Example Therefore production function interlink inputs and outputs as in the case provided. Taking for example the industrial production of sugar at a sugar mill. For production of sugar several inputs are required for production process to be complete. Although there are many inputs from labor, fuel, sugarcane supply, water and machinery the main inputs are sugarcane supply. To produce output y, input x1 and x2 are required for it to be produced. Therefore, such input set has the following effects on production of y. x is the sum input x1 and x2 referred to as the isoquant. Consider a situation where there are two main inputs x1 and x2 for production of sugar. Let x1 be sugarcane supply and x2 be labor. All these inputs work together for production of sugar. For Y quantity of sugar to be produced the firm need to use x1 quantity of sugarcane and x2 labor in the firm. Therefore, production process requires different inputs put together to produce a given output required. Inputs such as labor, capital and raw materials are equally important in the production process. In conclusion, addition of extra inputs in production clearly has great impact in production process. Production functions are determined by inputs that are used. Such inputs for example labor, capital and raw materials are used in the production process to determine the amount of outputs in

Migration, remittance and livelyhood Essay Example | Topics and Well Written Essays - 15000 words

Migration, remittance and livelyhood - Essay Example Chapter 1: INTRODUCTION 1.1Background Migration is a key element in the history of humanity in terms of continued existence and it has always gone hand in hand with the expansion of human race. On the other hand, over the years, the awareness of global migration and its impact to expansion has evolved, because of the growing recognition of the importance of remittance. The high quantity of migrant remittance flows to rising countries has guided to both pessimistic and optimistic views on the impacts of remittance. A wide range of literature and research has been available discussing the issue of remittance and its implications on expansion and migration. On the other hand, research to date has primarily concentrated on the impact of remittance to financial development, the connection between migration and remittance and so on. However, there remains an important gap examining the various processes of sending remittance and the wider problems remittance poses. The incomes that migrant s send home to their relatives, mainly global migrants, have expanded in current years to levels, which exceed direct foreign investments and official growth assistance. The World Bank estimated that worldwide remittances increased from about $85.6 billion in the year 2000 to about $167 billion in the year 2004 as contrasted to the direct foreign investment and development assistance. Presently, the bank estimates that global remittances reached about $318 billion in the year 2007, an amount of about $240 billion of that went to developing countries. Whereas potentially of similar importance, the quantity of internal remittances, sent mainly by urban migrants back to rural societies of their origin, as money or kind, are not commonly recorded and are hard to estimate. Extra migrants move internally than worldwide, and their earnings are inclined to be lower. Despite troubles of amount, the clearly huge amounts of remittances sent by global and internal migrants have attracted a lot of researchers to observe their impact on different aspects of growth. Recently, a growing sense of awareness has arisen with regard to the size and impact of informal remittances. Whereas formal remittances denote those remittances that enter a country during official banking channels, the informal remittances contain those money transfers that happen through private channels. Such private transfers contain remittances brought home by relatives, friends and even the migrant herself/himself. Whereas formal remittances to increasing countries have totalled to more than $167 billion in the year 2005, the point of informal remittances is practically unknown for the reason that they be inclined to flow through private channels. Estimates of the range of informal remittances differ widely, ranging from about 35 to 250 percent of formal remittances. This paper aims to fill this research gap by talking about the

Learning to Look Essay Example | Topics and Well Written Essays - 500 words

Learning to Look - Essay Example This feature makes it be more attractive to youth who participates in various activities such as games. Secondly, the products come in various colors in order to satisfy the interests of diverse range of customers. Different customers prefer products that have been branded using specific colors. In order to satisfy all market segments, Pepsi Company has branded the products using ribbons of different colors. Third, the products have been packed using different masses. This is to cater for different age groups ranging from small children to adults. Fourth, the bottle surface is rough rather than smooth an aspect that would make it not to slip from the hands of the users. Lastly, the products have been presented in different forms. These include unflavored and flavored water. This makes the customer to select his/her choice of the product (MacRury 2009). Three principles of art are well represented in this advert. First, art principle that is represented is repetition. The name Aquafina has been repeated in all related products. This makes the products to be distinct. Secondly, an aspect of variety is seen through the advert. The company has advertised variety of the products in order to attract different parts of the customers. In addition, this is aimed at increasing the market size. Lastly, the principle of unity is also well presented. All products are presented in one magazine an aspect that creates a unifying factor towards the products. This plays a very great role in segmenting the market. The product being advertised is refreshment. It has been advertised in youth magazine as a result, the major target of the advert is the teenagers. The text accompanying the product is simple to understand an aspect that makes the readers understand the use of the product. The clear image characterizes the product as of high quality and healthy for human consumption. This would

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

A Comparison of Men and Women Essay -- comparison compare contrast ess

Men vs. Women      Ã‚  Ã‚  Ã‚  Ã‚   I do not pretend to be a complete expert in the vast world of men and women. However, as one of these creatures, I decided early on in life to do my best to figure out the relationship between us and our counterparts. This was very interesting to me because, unlike most people, I do not believe that we simply "evolved" to become what we are today. I believe we were created the way we are by a very big God who knew what He was doing, and did it for a purpose.   After a mere 18 years of observation, I have concluded that we as humans are trying to look too deeply into the purpose of "man" and "woman." We make the relationship too complicated. We need to stop prying into why men like football and women like quilts, and simply accept that we do. That is the way it is. And as I shall point out, that is the way it is best.      Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   You may have recoiled at my earlier statement that men like football and women like quilts. I admit that it is a gross simplification of the differences between men and women.   However, you knew what I was talking about. These are the stereotypes that have been pounded into our brains since we were age two.   The man is the grunting, unfeeling one in the easy chair, who only takes a break from football to work on his car, or go drink with his buddies.   He is a brute, and is not interested in communication, only sex.   The woman is the one who screams at spiders, nags at the children, shops till she drops and holds those amazing sessions with her friends where all who are present talk at the exact same time for an hour and then pack up the coffee cups and diaper bags and leave with a complete understanding of everything that was said.        Ã‚  Ã‚  Ã‚  ... ...us into a concentrated effort to fulfill the desires of our spouses. It is then that we would find more harmony in our homes. As Henry W. Longfellow wrote in "Hiawatha": "As to the bow the cord is/So unto man is woman;/Tho' she bends him,/She obeys him./Tho' she draws him,/Yet she follows;/Useless each without the other."   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   And so we are.      Works Cited Tannen, Deborah. "Sex, Lies and Conversation." The McGraw-Hill Reader: Issues Across the Disciplines 8th edition. Ed. Gilbert H. Muller. Boston: McGraw- Hill, 2003. 229. The Holy Bible, New International Version. Grand Rapids: Zondervan, 1973. Theroux, Paul. "Being a Man." The McGraw -Hill Reader: Issues Across the Disciplines 8th edition. Ed. Gilbert H. Muller. Boston: Mc-Graw-Hill, 2003. 221, 219-220. Weber, Stu. Tender Warrior. Sisters: Multnomah, 1999. 117-118.