Chrominimum Essays - Occupational Safety And Health,

Chrominimum Chris Nicholatos 11/29/99 Mr. Cicero Block-D Chromium Chromium is a metal found in natural deposits as ores containing other elements. Chromium is a steel-gray, hard metal that is very brittle. It is classified as a heavy metal. After its refined from the ore chromite its compounds are used in leather tanning and manufacturing of chromic acid, pigments, and corrosion-resistant chrome products. The greatest use of chromium is in metal alloys such as magnetic tapes, paint pigments, cement, paper, and stainless steel. It is also used as an ingrediant in drilling mud, which is used to drill oil wells. Humans do need a certain amount of trivalent chromium to maintain good health. Although, in other forms, chromium can be toxic for humans. Workers in chromium products facilities have increased risks of cancer of the lungs and nose. In 1974, Congess passes the Safe Drinking Water Act. This act required EPA to determine safe levels of chemicals in drinking water which might cauase health problems. These levels are called Maximum Contaminant Level Goals or MCLGs'. The MCLG for chromium is 0.1 parts per million or PPMs'. At this level there is no potential for health problems. This and all other standards for water quality are called National Primary Drinking Water Gegulations. All public water supplies must abide by these regulations. Short-term effects can include, but are not limited to, skin irritation or ulceration. This occurs when a person is exposed to chromium at levels that exceed MCL standards for a relatively short period of time. Long-term effects can include, but are not limited to, damage to liver, kidneys, circulatory and nerve tissue, and skin irratation. This occurs when a person is exposed to chromium at level above MCL standards over a lifetime. Production of chromium contaminated water was about 250,000 tons in 1992. Chromium occurs mostly as chrome iron ore and is widley found in soils and plants, it is rare in natural water. The two largest sources of chromium emissions in the atmosphere are fom the chemical manufacturing industry and combustion of natural gas, oil, and coal. From 1987 to 1993, according to the Toxic Release Inventory, chromium compound released to land and water totaled nearly 200 million pounds. The releases were primarily from industrial organic chemical industries. The largest releases occurred in Texas and North Carolina. The largest direct release to water occurred in Georgia and Pennsylvania. When released to land, chromium compounds bind to soil are not likely to migrate to ground water. They are very persistant in water as sediments. There is a high potential for accumulation of chromuim in aquatic life. Now, EPA monitors your drinking water supply. They take samples and analyze the water to make sure the chromium levels do not exceed MCL standards of 0.1 ppm. If the levels are exceeded the officials must take steps to reduce the contamination. Some steps that have been approved by the EPA for the removal of chromium are: Coagulation/Filtration, Ion Exchange, Reverse Osmosis, Lime Softening. Also, when chromium levels exceed health standards EPA must notify the general public by newspaper, radio, television, or other means. Currently Texas has the highest rate of toxins released into water and land. In closing Massachusettes in general is not in any serious danger of contamination by chromium. Only industrialzed cities and cities with nuclear power plants and facilities. But since are current status is good in that department we should do everything in our power to keep it that way. Science Essays

Solar Energy Essays - Energy Conversion, Renewable Energy

Solar Energy Essays - Energy Conversion, Renewable Energy Solar Energy Tran 1 Solar Energy About 47 percent of the energy that the sun releases to the earth actually reaches the ground. About a third is reflected directly back into space by the atmosphere. The time in which solar energy is available, is also the time we least need it least - daytime. Because the sun's energy cannot be stored for use another time, we need to convert the suns energy into an energy that can be stored. One possible method of storing solar energy is by heating water that can be insulated. The water is heated by passing it through hollow panels. Black-coated steal plates are used because dark colors absorb heat more efficiently. However, this method only supplies enough energy for activities such as washing and bathing. The solar panels generate low grade heat, that is, they generate low temperatures for the amount of heat needed in a day. In order to generate high grade heat, intense enough to convert water into high-pressure steam which can then be used to turn electric generators there must be another method. The concentrated beams of sunlight are collected in a device called a solar furnace, which acts on the same principles as a large magnifying glass. The solar furnace takes the sunlight from a large area and by the use of lenses and mirrors can focus the light into a very small area. Very elaborate solar furnaces have machines that angle the mirrors and lenses to the sun all day. This system can provide sizable amounts of electricity and create extremely high temperatures of over 6000 degrees Fahrenheit. Solar energy generators are very clean, little waste is emitted from the generators into the environment. The use of coal, oil and gasoline is a constant drain, economically and environmentally. Will solar energy be the wave of the future? Could the worlds Tran 2 requirement of energy be fulfilled by the powerhouse of our galaxy - the sun? Automobiles in the future will probably run on solar energy, and houses will have solar heaters. Solar cells today are mostly made of silicon, one of the most common elements on Earth. The crystalline silicon solar cell was one of the first types to be developed and it is still the most common type in use today. They do not pollute the atmosphere and they leave behind no harmful waste products. Photovoltaic cells work effectively even in cloudy weather and unlike solar heaters, are more efficient at low temperatures. They do their job silently and there are no moving parts to wear out. It is no wonder that one marvels on how such a device would function. To understand how a solar cell works, it is necessary to go back to some basic atomic concepts. In the simplest model of the atom, electrons orbit a central nucleus, composed of protons and neutrons. Each electron carries one negative charge and each proton one positive charge. Neutrons carry no charge. Every atom has the same number of electrons as there are protons, so, on the whole, it is electrically neutral. The electrons have discrete kinetic energy levels, which increase with the orbital radius. When atoms bond together to form a solid, the electron energy levels merge into bands. In electrical conductors, these bands are continuous but in insulators and semiconductors there is an energy gap, in which no electron orbits can exist, between the inner valence band and outer conduction band [Book 1]. Valence electrons help to bind together the atoms in a solid by orbiting 2 adjacent nuclei, while conduction electrons, being less closely bound to the nuclei, are free to move in response to an applied voltage or electric field. The fewer conduction electrons there are, the higher the electrical resistively of the material. Tran 3 In semiconductors, the materials from which solar sells are made, the energy gap E.g. is fairly small. Because of this, electrons in the valence band can easily be made to jump to the conduction band by the injection of energy, either in the form of heat or light [Book 4]. This explains why the high resistively of semiconductors decreases as the temperature is raised or the material illuminated. The excitation of valence electrons to the conduction band is best accomplished when the semiconductor is in the crystalline state, i.e. when the atoms are arranged in a precise geometrical formation or lattice. At room temperature and low illumination, pure or so-called intrinsic semiconductors have a high resistively. But the

Nation States Essay Example | Topics and Well Written Essays - 750 words

Nation States - Essay Example processing immediate and untrammeled power over a contiguous territory occupied, in theory, by a population homogenous in speech, culture, and ethnicity. (p. 2) Simply put, capitalism relies on nation-states to maintain local conditions favourable to a culture of capitalist accumulation as well as to help it navigate the economy. The nation state holds the power which assures the creation and reproduction of the capitalist mode of production through a combination of procedures and processes. Hence, the development of capitalism is largely dependent on the progress of the nation-state and the movements within. Depending on one’s standpoint, the role of nation-state in capitalism is either viewed positively or negatively. For instance, Marxist adherents argue that capitalism was an upshot of the English feudalism and that its evolution resulted to a social malady where the sector responsible for the production of goods is protected by the state, to the disadvantage of the labor and the populace in general. There are varying factors in the development of nation-states. Experiences vary from one country to another. For some, nationhood is achieved due to internal developments while for some; it was realized as a result of some crisis which could be external in nature. In the case of the former, it is attained when a movement has succeeded in mobilizing the masses around one common conception of nationhood; while for the latter, political sovereignty is achieved under extraordinary and short-lived circumstances arising from a regional or global crisis rather than strictly internal developments. (Roshwald p. 2) The existence of nation-states has noble objectives. This is what appeals to people within its territory. Constitutions of countries cite these lofty ideals and while there might be some variations, they all bespeak of one important concept and that is identity. According to Martha Cotham et al., the concept of nationalism is similar to that of social

Project Statistics Example | Topics and Well Written Essays - 1250 words

Statistics Project Example The main procedure utilized in this study was regression analysis. It was utilized to explain the total variation of the dependent variable, the price of housing. The dependent variable was accompanied by 5 variables, which were tested against the dependent variable to determine how much of the total variation is explained. The analyses also discussed the comparison of the different regression models, and determine which model is the most effective. In regards to the regression analysis results, it is clearly evident that model 4 and 5 are the strongest model and model 1 being the weakest. Model 2 and 3 does not apply because of the reasons given. The first regression analysis step was to input all the collected data from the surveys into a spreadsheet. This process allows efficient running of regression models. After all the data was entered, there was formulation of the initial regression model. The analysis was done as in the next section. In summary, basing on the multiple regression above it is observed that the cost of construction, inflation rates, interest rates and real property gains tax influence negatively the price of housing. On the other hand population influences positively the price of housing. The analysis of this model can be further analyzed to ascertain the strength of the influence as seen in the next section. This first regression analysis shows a relatively weak model. The coefficient of Determination(R squared) shows that only 4% of the total variation is explained by the cost of construction factor. The standard error is 22.39, determined by the low R squared. In regards to the hypothesis testing, by considering an alpha of 0.05, the results indicate that this age variable is to be rejected. The independent variable of cost of construction demonstrates that the higher the cost of construction is, the less the price of housing and this is in line with several studies done. Thus the performance is less by -0.46633.

Kant and Mill Essay Example | Topics and Well Written Essays - 500 words

Kant and Mill - Essay Example For instance, the gifts of nature such as talents of the mind, encompassing understanding, wit and judgment, as well as qualities of temperament, such as courage, resolution and perseverance are good and desirable for many purposes; however, Kant insists that their goodness is conditional for such things may be extremely evil and harmful without a good will (Baxley 8). Mill believes that something is right if it produces the greatest good for the greatest number (Driver 3). Simply, Mill promoted the general good, that is, tenets and social policy should always endeavor to contribute for the good of the society (MacKinnon 32). Mill believes that the morally best alternative is that which produces the greatest utility, where utility is described in terms of happiness or pleasure; moreover, Mill encourages individuals to do which produces the greatest form of happiness or pleasure for the greatest number of people (McKinnon 32). Mill stressed that something good is anything that is desirable; hence, the individual can only find out what is desirable by attempting to discover what is essentially desired but with this he aims for the higher pleasures in life (Driver 51). Neither Kant nor Mill thought that people usually self-consciously apply the criterion of right action by asking themselves the driving force of why they are doing something good (Jacobs 93). Moreover, they both acclaimed that individuals tend to act on the basis of dispositions to judge and appreciate situations in certain sorts of ways, and in that respect, they both established a role for the virtues (Jacobs 93). Kant and Mill both wrote about the significance of virtues; still, in their views of morality, what makes for a good quality is the fact that the agent acts in accordance with the basic principle (Jacobs 93). Jacobs highlighted that in both Kant’s and Mill’s

Statistical techniques for cryptanalysis

Statistical techniques for cryptanalysis Introduction: Cryptography is the art of writing messages in code or cipher, to disguise, and thereby secure the content of a particular stream of text. When encrypted, a plain text message can be revealed only through the use of the key used to encode the cipher. Cryptography does not mask the existence of the message, but does disguise its content [1]. In contrary, cryptanalysis is the art of recovering the plaintext of a message without access to the key. Successful cryptanalysis may recover the plaintext or the key for a specific ciphertext [2]. There are five general types of cryptanalytic attacks:- 1. Ciphertext-only attack: In this type of attack, the cryptanalyst has a series of cipher texts encrypted using the same encryption algorithm. Then, the cryptanalyst deduces the plain text of each of the cipher texts or identifies the key used to encrypt the cipher text 2. Known-plaintext attack: In this type of attack, the cryptanalyst has a series of ciphertext and their corresponding plaintext values encrypted using a specific key. The cryptanalyst then tries to deduce the key by forming a relationship between the ciphertext and plaintext entries. 3. Chosen-plaintext attack: In this type of attack, the cryptanalyst not only has access to the ciphertext and associated plaintext for several messages, but he also chooses the plaintext that gets encrypted. His job is to deduce the key used to encrypt the messages or an algorithm to decrypt any new messages encrypted with the same key. 4. Frequency analysis: It is the study of thefrequency of lettersor groups of letters in aciphertext. The method is used as an aid to breakingclassical ciphers. Frequency analysis is based on the fact that, in any given stretch of written language, certain letters and combinations of letters occur with varying frequencies. 5. Rubber-hose cryptanalysis: The cryptanalyst threatens, tortures or blackmails the person who has the key until they give it up. Among the many cryptanalytic techniques, frequency analysis or frequency counting is the most basic technique applied to break substitution cipher based algorithms, among the varied list of attack techniques. The basic use of frequency analysis is to first count the frequency of ciphertext letters and then associate guessed plaintext letters with them. More complex use of statistics can be conceived, such as considering counts of pairs of letters digrams, trigrams, and so on. This is done to provide more information to the cryptanalyst. It exploits the weakness in the substitution cipher algorithm to encrypt similar plaintext letters to similar ciphertext letters. Frequency analysis based cryptanalysis techniques were used to break ciphers based on the traditional cryptographic algorithms, but they do not work well with the modern block cipher based cryptographic algorithms. Statistical properties of English: Frequency analysis based cryptanalysis uses the fact that natural language is not random in nature and single alphabetic based substitution does not hide the statistical properties of the natural language. In the case of encryption using monoalphabetic substitution, to start deciphering the encryption it is useful to get a frequency count of all the letters. The most frequent letter may represent the most common letter in English, E followed by T, A, O and I whereas the least frequent are Q, Z and X [7]. Statistical patterns in a language can be detected by tracing the redundancy of the text in the language. It has been realized that various universal regularities characterize text from different domains and languages. The best-known is Zipfs law on the distribution of word frequencies [5], according to which the frequency of terms in a collection decreases inversely to the rank of the terms. Zipfs law has been found to apply to collections of written documents in virtually all langu ages [5]. English language characters have a very high redundancy rate when used for cryptographic substitutions. If we have a message encrypted using the substitution cipher that needs to be cracked, we can use frequency analysis. In other words, if the sender has used an encryption scheme, that replaces one letter in the English to be another letter in English, we can still recognize the original plain text as, the frequency characteristics of the original plain text will be passed on the new cipher text characters [4]. To apply frequency analysis, we will need to know the frequency of every letter in the English alphabet, or the frequency characteristics of the language used by the sender to encrypt the text. Below is a list of average frequencies for letters in the English language. So, for example, the letter E accounts for 12.7% of all letters in English, whereas Z accounts for 0.1 %. All the frequencies are tabulated and plotted below:- For example, let us consider the following sentence: We study Cryptography as part of our course. Using a simple substitution cipher, let us consider the following: a->c , b-> d, c->e..w->y, x->z, y->a, z->b So, the cipher text becomes: yg uvwfa etarvqitcrja cu rctv qh qwt eqwtug. A simple frequency analysis of the cipher text can be carried out and the results are as given below: The above data can be used by a cryptanalyst to identify the key or the plaintext by using simple substitution to the cipher text till a suitable plaintext value is not identified. Apart from the use of mono alphabetic frequency analysis, cryptanalysts also identify frequency of paired letters better known as digram frequency and that of three letter words, called as Trigram frequencies. These help the cryptanalyst to exploit the redundant features of English language to break the cipher. The most common Digrams (in order): th, he, in, en, nt, re, er, an, ti, es, on, at, se, nd, or, ar, al, te, co, de, to, ra, et, ed, it, sa, em, ro. The most common Trigrams (in order): the, and, tha, ent, ing, ion, tio, for, nde, has, nce, edt, tis, oft, sth, men Table 1: Digram and Trigram Frequencies [6] These help in identifying the most commonly used terms in English to break a cipher. The digram frequencies are used to break two letter words such as an, to, of etc and the trigram frequencies are used to break three letter words such as the, are, for etc. After breaking a significant two letter and three letter words, it is practically east to identify the key from the cracked values of plaintext by matching the corresponding values in the ciphertext. This huge weakness in English language is used to break cipher texts encrypted using simple algorithms that make use of English alphabets. In practice the use of frequency analysis consists of first counting the frequency of ciphertext letters and then assigning guessed plaintext letters to them. Many letters will occur with roughly the same frequency, so a cipher with Xs may indeed map X onto R, but could also map X onto G or M. But some letters in every language using letters will occur more frequently; if there are more Xs in the c iphertext than anything else, its a good guess for English plaintext that X is a substitution for E. But T and A are also very common in English text, so X might be either of them also [4]. Thus the cryptanalyst may need to try several combinations of mappings between ciphertext and plaintext letters. Once the common single letter frequencies have been resolved, then paired patterns and other patterns are solved. Finally, when sufficient characters have been cracked, then the rest of the text can be cracked using simple substitution. Frequency analysis is extremely effective against the simpler substitution ciphers and will break astonishingly short cipher texts with ease. Attacks on Traditional algorithms Encrypting using traditional algorithms have been defenseless against cryptanalytic attacks as they use bit by bit encryption, which can be easily broken using frequency analysis based attacks. 1. Caesar Cipher: Considering the case of one of the oldest ciphers, the Caesar Cipher, this cipher replaces one letter of the plaintext with another to produce the ciphertext, and any particular letter in the plaintext will always, turn into the same letter in the cipher for all instance of the plaintext character. For instance, all Bs will turn into Fs. Frequency analysis is based on the fact that certain letters, and combinations of letters, appear with characteristic frequency in essentially all texts in a particular language [9]. For instance, in the English language, E is very common, while X is not. Likewise, ST, NG, TH, and QU are common combinations, while XT, NZ, and QJ are very uncommon, or even impossible to occur in English. This clearly shows how the Caesar cipher can be broken with ease by just identifying the frequency of each letter in the cipher text. A message encrypted using Caesar cipher is extremely insecure as an exhaustive cryptanalysis on the keys easily breaks the code. 2. Substitution Ciphers: The Caesar cipher forms a subset of the entire set of substitution ciphers. Here, the key of the encryption process is the permutation of all the twenty six characters of the English alphabets. Rather than choosing a particular key for all encryption process, we use a different key for successive encryption processes. This technique increases the number of possible key to 26!, which is about 4 X 1026, which eliminates the exhaustive cryptanalysis attack on the keyspace [7]. To decrypt the cipher the, statistical frequency distribution of single letter occurrence in English language is analyzed. Then, the digram and trigram frequencies of standard English words are compared with the frequencies of the trigrams in the cipher to finally reconstruct the key and in turn decipher the text. This is an efficient method to break the substitution cipher as, each plaintext letter is represented by the same ciphertext letter in the message. So, all properties of plaintext are carried on to the cipher text. 3. Vigenere Cipher: In a Vigenere cipher, there is greater security as, a given plaintext letter is not always represented by the same ciphertext letter. This is achieved by using a sequence of n different substitution ciphers to encrypt a message. This technique increases the possible number of keys from 26! to (26!)n. Although this was considered to be unbreakable, the Kasiskis method of attacking a Vigenere cipher yielded successful results of decrypting the message. According to this method, the first step is to find the key length (n). Find identical segments of plain text that get encrypted to the same ciphertext, when they are b positions apart, where b=0 mod n. According to Kasiski, the next step is to find all the identical segments of length greater than 3, and record the distance between them [7]. This can then be used to predict the length of the key (n). Once this is found the key is found by an exhaustive search of the keyspace for all possible combinations to identify the key. This is done by substituting all possible values for n to generate substrings. Once the substring is formed, the plaintext message can be automatically identified by using the back substitution of the key into the cipher [7]. This can be done for all possible values for n until finally arriving at the actual key, which reveals the plaintext that was encrypted. This method can take a long time to break the key to identify the plaintext incase the key length is very long, as the keyspace value would be large for larger keys. Defeating frequency based attacks: Frequency based attacks have been used for a long time to break traditional encryption algorithms. It uses the fact that, traditional encryption algorithms do not eliminate the statistical properties of the language upon encryption. The first way to defeat frequency based attacks is to encrypt blocks of characters at a time rather than single letters [7]. This would ensure that, the same text in the plaintext is not encrypted to the same text in the ciphertext upon encryption. For e.g., if we use the Caesar cipher encryption scheme, the word ADDITIONAL will be encrypted to CFFKVKQPCN, we can see that the alphabets A, D and I are repeated more than once and at each instance, the encryption scheme used always encrypts A to C, D to F and I to K. This can clearly be used during frequency analysis to analyze the redundancy of the characters and in turn map them back to get the original plaintext character. Using a block encryption scheme, one can be satisfied that, this phenomenon does not occur as, in a block encryption scheme, the whole plaintext is broken into chunks or blocks of data, that is fed in as input to the encryption algorithm. The algorithm then, reads the input block along with the key and encrypts th e complete block of plaintext, rather than individual characters, so there is a smaller chance that two blocks will produce the same chunk of ciphertext. The second way of defeating frequency analysis is to make use of synonyms of words [7], rather than repeating the same word over and over again in a sentence. There are a lot of words in English, which have more than one synonym, thus providing with a set of words to be used as convenient in the particular context. To help in the selection of a synonym, grammar checking would have to be used to ensure that, the meaning expressed in the sentence is not altered by changing the words. Attacks against this technique could include creating a list of the best synonyms, but this would not help the attacker as different word could be used at each instance the same meaning needs to be expressed, defeating the benefit of this technique. This technique of using alternate words to represent common words to defeat cryptanalysis attacks is called Homophones [7] in cryptography. A third technique that can effectively defeat cryptanalysis is Polyalphabetic substitution, that is, the use of several alphabets to encrypt the message [3], rather than using the same substitution technique again and again. The Vigenere Cipher is a form of Polyalphabetic cipher. This ensures that, no two characters are encrypted to the same ciphertext alphabet in the same message. This ensures that, direct frequency analysis of the cipher is not possible to successfully retrieve the original message. However, other techniques need to be used to identify the key length, if this is possible, then frequency analysis attack could be used to identify the original plaintext message successfully. Finally, a possible technique that could be used to defeat frequency analysis is to encrypt a single character of plaintext with two ciphertext characters [3]. Upon encountering the same character twice, then different characters should be used to encrypt the message. This can be achieved by using a key size double that of the plaintext message and then encrypting the same plaintext with two values in the key and save them together for the same plaintext character. This would ensure that no two plaintext characters will have the same ciphertext character, defeating the frequency analysis method of breaking the cipher. Modern encryption algorithms and cryptanalysis: Modern cryptographic algorithms take a better approach in defeating frequency analysis based attacks. The cryptographic algorithms nowadays use block encryption, rather than encrypting characters bit by bit, thus eliminating the redundancy of ciphertext alphabets for similar plaintext alphabets. Block ciphers are the central tool in the design of protocols for shared-key cryptography. A block cipher is a function E: {0, 1}k ÃÆ'- {0, 1}n à ¢Ãƒ ¢Ã¢â€š ¬Ã‚   {0, 1}n. This notation means that E takes two inputs, one being a k-bit string and the other an n-bit string, and returns an n-bit string [2]. The first input is the key, which is used to encrypt the secret message. The second string is called the plaintext, and the output is called a ciphertext. The key-length k and the block-length n are parameters associated to a specific block cipher. They vary from block cipher to block cipher, and depend on the design of the algorithm itself. Some of the most trusted symmetric ciphers inclu de AES, Triple-DES, Blowfish, CAST and IDEA. In public-key cryptography, the most commonly used cryptosystems are RSA and the Diffie-Hellman systems, which have not been found to have any vulnerabilities till date. Preferably, the block cipher E is a public specified algorithm. In typical usage, a random key K is chosen and kept secret between a pair of users. The function EK is used by the sender to encrypt the message, for a given key, before sending it to the intended receiver, who decrypts the message using the same key [2]. Security relies on the secrecy of the key. So, at first, one might think of the cryptanalysts goal as recovering the key K given some ciphertext, intercepted during transmission. The block cipher should be designed to make this task computationally difficult. In order to achieve this, the algorithms that are used to encrypt the message must be designed with a high degree of mathematical complexity, which cannot be reversed to obtain the plaintext from a known ciphertext. The length of the key used during encryption of a message plays an important role in deciding the effectiveness of an algorithm. Key length is conventionally measured in bits, and most of the well known strong ciphers have key lengths between 128 and 256 bits. A cipher is considered strong if, after years of attempts to find a weakness in the algorithm, there is no known effective cryptanalytic attack against it. This indicates that, the most efficient way of breaking an encrypted message without knowing the key used to encrypt it is to brute force it, i.e. trying all possible keys. The effort required to break an encrypted message is determined by the number of possible keys, known as thekeyspace. Knowing the speed of the computer to break the key, it is easy to calculate how long it would take to search the keyspace to break a particular cipher [2]. For example, considering a cipher that uses 128-bit keys, each bit can either be 0 or 1, so, there are 2128 or 3ÃÆ'-1038 keys approximately. Suppose we imagine that about ten billion computers are assigned the task of breaking the code, each capable of testing ten billion keys per second, then, the task of running through the entire keyspace would take around 3ÃÆ'-1018seconds, which is about 100 billion years. But, in fact, it would be necessary to run through only half the keyspace to hit upon the correct key, which would take around 50 billion years. This is longer than the estimated age of the universe according to modern cosmology, which is about 15 billion years [2]. This shows that, it is practically infeasible to crack modern cryptographic algorithms using Brute Force attacks. So, one can imagine the effectiveness of the modern cryptographic algorithms and their resistance towards cryptanalytic attacks. Conclusions: Cryptography has progressed in recent years and modern cryptographic algorithms have proved to be successful in defending against most forms of cryptanalytic attacks. Frequency analysis based attacks have proved to exploit the weaknesses in traditional encryption algorithms into revealing the plaintext message that was encrypted using them. The natural language used to encrypt messages is not considered to be random in nature, which is exploited by frequency counting based attacks. Based upon the frequency of letters that occur in the ciphertext, one can guess the plaintext characters due to their redundancy rate and the specific combination of letters in a word. This weakness can be repelled by using stream ciphers, which do not carry the redundancy in the plaintext to the ciphertext. Modern block cipher, encrypt a chunk of plaintext into ciphertext and vice versa, eliminating the redundancy of language used in encryption. Although the algorithm plays an important part, it is the key length used in block ciphers that helps in repelling cryptanalysis. Modern ciphers use a key length starting from 128 bits, eliminating the possibility of a brute force attack to decrypt the message. The higher the key length, the more time it takes to break these ciphers. These advantages have made modern cryptographic algorithms more popular among the security community. No known weaknesses have been found in these algorithms yet, that may allow one to identify the plaintext message. Bibliography: [1] Stallings, W., Cryptography and Network Security, Chapter 1, Third Edition, Prentice Hall, 2003 [2] Schneier, B., Applied Cryptography, Chapter 1, Second Edition, John Wiley Sons, New York City, New York, USA, 1996 [3] Hart, G.W., To Decode Short Cryptograms, Communications of the ACM 37(9), 1994, pp. 102-108 [4] Lee, K.W., Teh, C.E., Tan, Y.L., Decrypting English Text Using Enhanced Frequency Analysis, National Seminar on Science, Technology and Social Sciences (STSS 2006), Kuantan, Pahang, Malaysia [5] Zipf, GK., Human Behaviour and the Principle of Least Effort, 1949, Cambridge: Addison Wesley Publications. [6] Lewand, R.E., Cryptological Mathematics, The Mathematical Association of America, 2000, Pages 345-346 [7] Stamp, M and Low, R.M., Applied Cryptanalysis, 2007, Chapter 1 and 2, John Wiley Sons, New York City, New York, USA [8] http://www.simonsingh.net, Online internet frequency analysis tools [9] http://www.textalyser.net, online text analysis and frequency analysis information

Research Proposal Childhood Obesity Essay

The topic of this research proposal is addressing childhood obesity in the United States. This epidemic has been going on for many years now and has become an issue most recently being addressed by the United States government through their task force, which hopes to end this problem. By reviewing the many factors involved which include economic boundaries for the children’s families, early education in nutrition, and progress made in battling this epidemic thus far, we will be able to determine when it is the best time to introduce good nutritional knowledge and application, as well as physical activity, for children in the United States in hopes of ending this problem overall. In order to determine this answer, the researcher will need to research the changes that have taken place thus far by reviewing articles that show what certain states have been actively promoting healthy eating and physical activity, like in Portland ME who has educational programs for residents. This program also allows for scholarships for these programs for families who cannot afford the classes. The researcher will also have to review articles in the ProQuest database that show what has been studied so far regarding nutrition for young children as well as other sources like the White House website articles related to the task force being led by First Lady Michelle Obama. The researcher will also need to show an overview of the current problem at hand with one in three children in the country qualifying as obese. The researcher will review some of the problems that may be contributing factors like target marketing to children by fast food establishments and limited physical activity by children today, By reviewing all of this information, the researcher should be able to show progress made toward ending this problem and answer when good nutrition and physical activity should be introduced in a child’s life.

Kiddie Land Gym Essay

Starting in March Kiddie Land would begin to promote a new a new product Super Gym Outdoor children’s Exercise center. The problem or the issue was the company has never shipped something this big, they had to come up with ideas of how to make a profit and how to reach it to the customers. Case Questions: 1. Advantages and disadvantages of purchasing a two-wheeled trailer for each store to use for delivery of the Super Gym †¢ Advantage Kiddie land could do its own deliveries saving the company some money †¢ Disadvantage Bumpers on the newest autos cannot accommodate trailer hitches. 2. Advantages and disadvantages of using local trucking companies deliver from the retail stores to the customer †¢ Advantage According to market research 85% of the customers drive less than 25 minutes to the store, so with the flat rate of $40 per shipment it would be cheaper to deliver for the company. †¢ Disadvantage Local companies that were found prefer deliveries twice a week but not daily. 3. Advantages and disadvantages of stocking Super Gym at the distribution center and having the truck make deliveries to the retail stores also make deliveries to customers †¢ Advantages Consolidator-Ship more than one delivery to the retailer or customer equals fewer trips. †¢ Disadvantages Burning too much fuel with double deliveries to distribution center then retailer stores Squeezing an 18 wheeler into a subdivision would not make any sense Knocking down a couple of mail boxes and Truck tracks in some homeowner lawns. 4. Advantages and Disadvantages of charging customers for home delivery if unable to carry †¢ Advantage Charging customers for delivery would absorb the cost of $40 for delivery per set. †¢ Disadvantage Chasing away customers With added minor insects to catch customers attention may cost the company later. 5. I would prefer using Local trucking company due to The company can avoid expensive shipping and handling expense to the customers and Avoid charging the customers for home deliveries. 6. With a purchase of our new product the Super Gym Center we will deliver to your doorstep for free 7. My Follow up on SUV would be †¢ Do they have enough room for the Super Gym? †¢ To maintain sales, how many SUVs would the company require? †¢ How many employees would be willing to part with their trucks for company business and for how much?

Three Roads To One Hero essays

Three Roads To One Hero essays Throughout the two epics, Beowulf, and Gilgamesh, and the novel Grendel, we see certain heroic characteristics of the main characters. Although Beowulf, Grendel, and Gilgamesh all come to a heroic end, they differ in way in which they came to that end. In Beowulf we read of a great warrior who cares about nothing but honor and his people. In Gilgamesh, we see a man who comes to a realization of his mortality, and then does all he can to overcome that "weakness." Finally, in Grendel, we see a "monster" that was born in a cruel world, and comes to a cruel ending. Throughout the epic poem of Beowulf, we not only read of the heroism of Beowulf himself, but the guile of the antagonist, Grendel. By the fifth chapter, Beowulf is showing a characteristic that was vital to a Greek hero. He is boasting of his accomplishments. He tells of how he once fought a serpent in the open ocean. This might not seem to heroic, but you must attempt to become an archeological reader to begin fully understanding why this is so heroic. During the fist century of this millenium, one of the many things that scared people, and continues to do so today, is the unknown. Beowulf braved the unknown on not only land, but also where man has never belonged. He braved the unknown in the ocean. Grendel throughout the poem is, however, shown in a different light. He is a monster. He is a descendant of the first murderer, Cain. He kills simply for sport. He relishes in the blood of mankind. He is a monster who knows no bounds. In Grendel however, the point of view of the reader has changed. We now read from the point of view of the "monster." We see how he has been born into a world where he understands next to nothing, and does not even have the comfort of a true mother. He can talk to no one, save for a dragon that sees everything, past, present and future, and he is alone in a world of humans. There is no place of refuge where he can escape the world of hate that he ...

USS Saipan (CVL-48) - Cold War

USS Saipan (CVL-48) - Cold War USS Saipan (CVL-48) - Overview: Nation:  United States Type:  Light Aircraft Carrier Shipyard:  New York Shipbuilding Corporation Laid Down:  July 10, 1944 Launched:  July 8, 1945 Commissioned:  July 14, 1946 Fate:  Sold for scrap, 1976 USS Saipan (CVL-48) - Specifications: Displacement:  14,500 tons Length:  684 ft. Beam:  76.8 ft. (waterline) Draft:  28 ft. Propulsion:  Geared steam turbines, 4 Ãâ€" shafts Speed:  33 knots Complement:  1,721 men USS Saipan (CVL-48) - Armament: 10 Ãâ€" quadruple 40 mm guns Aircraft: 42-50 aircraft USS Saipan (CVL-48) - Design Construction: In 1941, with World War II underway in Europe and growing tensions with Japan, President Franklin D. Roosevelt became increasingly worried that the US Navy did not anticipate any new carriers joining the fleet until 1944.   To remedy the situation, he ordered the General Board to examine whether any of the light cruisers then being built could be converted into carriers to reinforce the services Lexington- and Yorktown-class ships.   Though the initial report recommended against such conversions, Roosevelt pressed the issue and a design to utilize several Cleveland-class light cruiser hulls then under construction was developed.   Following the Japanese attack on Pearl Harbor on December 7 and the US entry into the conflict, the US Navy moved to accelerate the construction of the new  Essex-class fleet carriers and approved the conversion of several cruisers into light carriers. Dubbed the Independence-class, the nine carriers that resulted from the program possessed narrow and short flight decks as a result of their light cruiser hulls.   Limited in their capabilities, the primary advantage of the class was the speed with which they could be completed.   Anticipating combat losses among the Independence-class ships, the US Navy moved forward with an improved light carrier design.   Though intended as carriers from the outset, the design of what became the Saipan-class drew heavily from the hull shape and machinery used in the Baltimore-class heavy cruisers.   This allowed for a wider and longer flight deck and improved seakeeping.   Other benefits included a higher speed, better hull subdivision, as well as stronger armor and enhanced anti-aircraft defenses.   As the new class was larger, it was capable of carrying a more sizable air group than its predecessors.    The lead ship of  class, USS Saipan (CVL-48), was laid down at the New York Shipbuilding Company (Camden, NJ) on July 10, 1944.   Named for the recently fought Battle of Saipan, construction moved forward over the next year and the carrier slid down the ways on July 8, 1945, with Harriet McCormack, wife of House Majority Leader John W. McCormack, serving as sponsor.   As workers moved to complete Saipan, the war ended.   As a result, it was commissioned into the peacetime US Navy on July 14, 1946, with Captain John G. Crommelin in command.       USS Saipan (CVL-48) - Early Service: Completing shakedown operations, Saipan received an assignment to train new pilots off Pensacola, FL.   Remaining in this role from September 1946 through April 1947, it then was transferred north to Norfolk.   Following exercises in the Caribbean, Saipan joined the Operational Development Force in December.   Tasked with assessing experimental equipment and developing new tactics, the force reported to the commander-in-chief of the Atlantic Fleet.   Working with ODF, Saipan primarily focused on crafting operational practices for using new jet aircraft at sea as well as electronic instrument evaluation.   After brief break from this duty in February 1948 to transport a delegation to Venezuela, the carrier resumed its operations off the Virginia Capes. Made flagship of Carrier Division 17 on April 17, Saipan steamed north Quonset Point, RI to embark Fighter Squadron 17A.   Over the course of the next three days, the entirety of the squadron qualified in the FH-1 Phantom.   This made it the first fully-qualified, carrier-based jet fighter squadron in the US Navy.   Relieved of flagship duties in June, Saipan underwent an overhaul at Norfolk the following month.   Returning to service with ODF, the carrier embarked a pair of Sikorsky XHJS and three Piasecki HRP-1 helicopters in December and sailed north to Greenland to aid in the rescue of eleven airmen who had become stranded.   Arriving offshore on the 28th, it remained on station until the men were rescued.   After a stop in Norfolk, Saipan proceeded south Guantanamo Bay where it conducted exercises for two months before rejoining ODF. USS Saipan (CVL-48) - Mediterranean to the Far East: The spring and summer of 1949 saw Saipan continue duty with ODF as well as conduct reservist training cruises north to Canada while also carrier qualifying Royal Canadian Navy pilots.   After another year of operating off the Virginia coast, the carrier received orders to assume the post of flagship of Carrier Division 14 with the US Sixth Fleet.   Sailing for the Mediterranean, Saipan remained abroad for three months before steaming back to Norfolk.   Rejoining the US Second Fleet, it spent the next two years in the Atlantic and Caribbean.   In October 1953, Saipan was directed to sail for the Far East to aid in supporting the truce that had recently ended the Korean War.    Transiting the Panama Canal, Saipan touched at Pearl Harbor before arriving at Yokosuka, Japan.   Taking station off the Korean coast, the carriers aircraft flew  surveillance and reconnaissance missions to assess Communist activity.   During the winter, Saipan provided air cover for a Japanese convey transporting Chinese prisoners of war to Taiwan.   After taking part in exercises in the Bonins in March 1954, the carrier ferried twenty-five AU-1 (ground attack) model Chance Vought Corsairs and five  Sikorsky H-19 Chickasaw helicopters to Indochina for transfer to the French who were engaged in the Battle of Dien Bien Phu.   Completing this mission, Saipan delivered helicopters to US Air Force personnel in the Philippines before resuming its station off Korea.   Ordered home later that spring, the carrier departed Japan on May 25 and returned to Norfolk via the Suez Canal. USS Saipan (CVL-48) - Transition: That fall, Saipan steamed south on a mission of mercy following Hurricane Hazel.   Arriving off Haiti in mid-October, the carrier delivered a variety of humanitarian and medical aid to the ravaged country.   Departing on October 20, Saipan made port at Norfolk for an overhaul prior to operations in the Caribbean and a second stint as the training carrier at Pensacola.   In the fall of 1955, it again received orders to aid in hurricane relief and moved south to the Mexican coast.   Using its helicopters, Saipan assisted in evacuating civilians and distributed aid to the population around Tampico.   After several months at Pensacola, the carrier was directed to make for Bayonne, NJ for decommissioning on October 3, 1957.   Too small relative to the Essex-, Midway-, and new Forrestal-class fleet carriers, Saipan was placed in reserve.      Reclassified AVT-6 (aircraft transport) on May 15, 1959, Saipan found new life in March 1963.   Transferred south to the Alabama Drydock and Shipbuilding Company in Mobile, the carrier was slated to be converted into a command ship.   Initially re-designated CC-3,  Saipan was instead re-classified as a major communications relay ship (AGMR-2) on September 1, 1964.   Seven months later, on April 8, 1965, the ship was renamed USS Arlington in recognition of one of the US Navys first radio stations.   Re-commissioned on August 27, 1966, Arlington underwent fitting out and shakedown operations into the new year before taking part in exercises in the Bay of Biscay.   In the late spring of 1967, the ship made preparations to deploy to the Pacific to take part in the Vietnam War.      Ã‚      USS Arlington (AGMR-2) - Vietnam Apollo: Sailing on July 7, 1967, Arlington passed through the Panama Canal and touched in Hawaii, Japan, and the Philippines before taking up a station in the Gulf of Tonkin.   Making three patrols in the South China Sea that fall, the ship provided reliable communications handling for the fleet and supported combat operations in the region.   Additional patrols followed in early 1968 and Arlington also participated in exercises in the Sea of Japan as well as made port calls in Hong Kong and Sydney.   Remaining in the Far East for most of 1968, the ship sailed for Pearl Harbor in December and later played a support role in the recovery of Apollo 8.   Returning to the waters off Vietnam in January, it continued to operate in the region until April when it departed to aid in the recovery of Apollo 10.    With this mission complete, Arlington sailed for Midway Atoll to provide communications support for a meeting between President Richard Nixon and South Vietnamese President Nguyen Van Thieu on June 8, 1969.   Briefly resuming its mission off Vietnam on June 27, the ship was again withdrawn the following month to aid NASA.   Arriving at Johnston Island, Arlington embarked Nixon on July 24 and then supported the return of Apollo 11.   With the successful recovery of Neil Armstrong and his crew, Nixon transferred to USS Hornet (CV-12) to meet with the astronauts.   Departing the area, Arlington sailed for Hawaii before departing for the West Coast.    Arriving at Long Beach, CA on August 29, Arlington then moved south to San Diego to begin the process of inactivation.   Decommissioned on January 14, 1970, the former carrier was stricken from the Navy List on August 15, 1975.   Briefly held, it was sold for scrap by the Defense Reutilization and Marketing Service on June 1, 1976.    Selected Sources DANFS: USS  Saipan  (CVL-48)NavSource: USS  Saipan  (CVL-48)USS  Saipan  (CV-48) Association

Reviewing Paintings Essay Example | Topics and Well Written Essays - 750 words

Reviewing Paintings - Essay Example In the paper "Nudity and 19th Century Americans" the focus will be placed on American attitudes towards nudity during the 19th century. In order to gauge the American response, three art works containing nudity at varying degrees will be analyzed for the responses that they inspired from this population. The works featured here include Nymph with Bittern by William Rush, Ariadne Asleep on the Island of Naxos by John Vanderlyn and Raphaelle Peale’s Venus Rising from the Sea-A Deception. Nymph with Bittern is a statue of a woman who is draped from the waist down. Upon her shoulder she bears the weight of a bittern. This statue had been created specifically for public display. After the Yellow Fever epidemic, the city of Philadelphia built their first water treatment facility which was located in what William Penn had decided would be the town center. The center was a place where all of the government buildings were to be located, however the area sat empty for a while, as Pennâ €™s carefully designed plans were not followed. Rush carved the statue and it was placed in this center. There were no major uprisings or protests because of this stature. The level of nudity displayed seems to have been acceptable among the people. Rush’s work was appreciated and he was commissioned to create other works. On the contrary, the work of Vanderlyn was not so well received. Vanderlyn is considered to be the first American painter to use nudes. In his painting the woman lying on the grass is totally nude accept. for a small piece of cloth on her thigh. It was Vanderlyn’s mission to enhance the tastes of the American people. He had studied abroad in France and this overseas education influenced his work. Of the painting it has been reported that â€Å"†¦when it was first displayed in America in 1815, its sensual approach caused controversy and as late as the 1890s, when it was firmly ensconced in the Pennsylvania Academy’s collection, there protests against its ‘flagrant indelicacy’ and calls for it to be removed from display† (Venus Observations 2009). For a while the painting resided in the home of Asher B. Durand who had a great appreciation for it. However, Durand kept the painting covered with a veil so that it would no offend his guests (Lane 1999). Raphaelle Peale felt that all of the controversy over paintings of nudes was ridiculous. He was a friend of Durand and had taken interest, not only veiled painting, but in people’s attitudes towards nude paintings. As it was reported â€Å"†¦Raphaelle Peale, chose to satirise this prudery in a painting of his own† (Lane 1999). Even his father held the position that such paintings should be covered up. Peale however did not agree. To prove a point and scoff at the conservatives Peale created Venus Rising from the Sea-A deception. The painting is of a woman who is rising from her bath, but see cannot be seen because she is behind a sheet that is secured to a clothes line. The sheet, however, is exquisite. The history of these three works of art demonstrates that there was some tolerance to nudity amongst Americans in the 19th century. The statue by Rush, Nymph with Bittern, seems to have been acceptable. The woman in it is only partially nude. However, when it came to full nudity the people gathered to protest. Full

Pope John Paul II, A man for others Essay Example | Topics and Well Written Essays - 1500 words

Pope John Paul II, A man for others - Essay Example In the later part of his pontificate, he spoke against war, communism, dictatorship, materialism, abortion, contraception, relativism and unrestrained capitalism. John Paul II was Pope during a period in which the Catholic Church's influence declined in developed countries but expanded in the Third World countries. During his reign, the pope traveled extensively, visiting over 100 countries, more than any of his predecessors. He remains one of the most-traveled world leaders in history. He was fluent in numerous languages. He canonized a great number of people. In 1992, he was diagnosed with Parkinson's disease. On April 2, 2005 at 9:37 p.m. local time, Pope John Paul II died in the Papal Apartments. Millions of people came to Rome to pay their respects for his funeral. This paper researches how he was a man for others and how he developed himself through his childhood and adulthood days. Childhood days: St.John Paul II was born as Karol Jozef Wojtyla in Wadowice, a town of 8,000 Catholics and 2,000 Jews 35 miles southwest of Krakow in 1920, the second son of Karol Wojtyla Sr., a retired army officer and tailor, and Emilia Kaczorowska Wojtyla, a schoolteacher of Lithuanian descent. The Wojtylas were strict Catholics, but did not share the anti-Semitic views of many Poles..His playmate Kluger had once remarked about the pope as "The people in the Vatican do not know Jews, and previous popes did not know Jews but this pope is a friend of the Jewish people because he knows Jewish people." In fact, Wojtyla became the first pope to visit a synagogue and the first to visit the memorial at Auschwitz to victims of the Holocaust. In ending the Catholic-Jewish estrangement, he called Jews "our elder brothers." John Paul II was very athletic in his youth days: he played soccer as a goal keeper, took daring swims in the flooded Skawa River and enjoyed skiing, hiking, mountain climbing and kayaking. He was also an excellent student. Adversities: His infant sister died before he was born. In 1929 his mother died of heart and kidney problems. When he was 12, his 26 year old brother died of scarlet fever. He himself had two near-misses with mortality in his youth. He was hit once by a streetcar and again by a truck in 1944 while he was a college student. He had been beset by physical difficulties including a dislocated shoulder, a broken thigh that led to femur-replacement surgery, the removal of a precancerous tumor from his colon Passions and occupations: Wojtyla's passions in those early years were poetry, religion and the theater. After graduating from secondary school in 1938, he and his father moved to Krakow where he enrolled at Jagiellonian University to study literature and philosophy. He also joined an experimental theater group and participated in poetry readings and literary discussion groups. He was an intense and gifted actor, and a fine singer. After the Germans invaded Poland, he escaped deportation and imprisonment in late 1940 by taking a job as a stone cutter in a quarry. His father was very much interested in making him a priest before he died but died with his interest unfulfilled. After his father's death he began studying at an underground seminary in Krakow and registered for theology courses at the university. He continued his studies,