Changing Decisions

      Recently, changing one's promise has been an issue as president election is approaching. Current president is now being evaluated by electors and their questioning whether candidates have capability to keep their promises. It is true that “ Man should not change that they have said”, however we should recognize that changing some decisions according to the situation in necessary. To live in modern society, revised change should not be prohibited but proposed.

Decisions, it might seem unnecessary in human lives however it modified human history several times significantly. For instance, Truman’s decision to bomb Hiroshima has changed the history of science which easily enabled homicide. So, such decisions should be made seriously. So to be a perfect decision, it should be revised for several times

Decisions should be revised due to the numerous changes of the situation. When situations change, decisions should adapt to the changed situation to maintain its’ effectiveness. For example, when one decides to go abroad one week later and one have recognized that typhoon will strike one week after, one should change decision like changing dates. Even though this is an example of unimportant decision, some important decisions like which are from army seldom change following to the climate. If one refuses to change decisions when circumstances change the decisions would not have power than the previous one possessed. In addition, decisions are sometimes forced to change when circumstances modify. Even though one have decided to go to the University they wanted to attend, one should change their decisions when his or her scores are to low that one could not even register for the test

Moreover, unrevised decisions provoke anxiety and nervousness. When a person changes their decision when the situation changes, they would feel relaxed because revised decisions are the latest and has safety proved. On the other hand, when decisions are unrevised one would gradually feel anxiety because they believe that there decisions are old an inadequate to the changed circumstances.  An epitome would be the changed standards of acceptance of a school. When one prepared to go to the school and received qualification the school required previously, but they may change decision to go to that school because one cannot be accepted following to the changed standards. However, if one does not change his or her decision one would be nervous due to the decreased possibility of being accepted. So, one should change decision following to the changes of situation to be satisfied and relaxed.

    Furthermore, education changes the decision. When a person is educated, they might change the decision that they have made earlier.  After learning a specific fact that wasn’t previously educated, decisions might change because the fact will prove that the latter would be a better one. So, when one is educated they would have variety of decisions to make and also they would have improved ability. Rather than educations, there are also some changed circumstances that changes decisions like ability and accidents. For example, when one had a traffic accident and as a result one could not dance, one should change their decision being a dancer.

     In conclusion, one’s decision should be flexible rather than being stable to maintain the effectiveness of the decision, to be comfortable and modification which occurred in oneself. In the global society, stubborn leaders are not welcomed because they do not change imperfect decisions that they have made. To add, successful managers usually revise their decisions over and over when the situation changes over and over to make the situation easily adapt to the situation.

History of cryptology

History of cryptology

10B1 조형우

    Cryptography is derived from combination of two ancient Greek Words krypto meaning hidden and grafo meaning to write. Therefore the literal meaning of cryptology is “hidden writing” which is crucial tool for secure communication. Nevertheless, the first intention of the cryptography was not related to concealing the message, it was utilized to decorate tombs to make one’s life seem noble in Egypt, around 2,000 B.C. Cryptology have started from decoration but it developed and started to function as a tool to conceal messages. This history of cryptology is widely classified in three eras: from ancient civilizations to 1940s, around Second World War, after Second World War to modern society.

   

Cryptography was used for mainly three purposes in the ancient society which is private communications, delineation of religion and secure communication for military. The most important function in the ancient period was delineation of religion and decoration of tombs. For example, in the Book of Jeremiah, a few English words transformed into other English words: "hob"="sly", "hold"="slow", "holy"="slob", "horn"="slim", "zoo"="all", "irk"="rip", "low"="old", "glow"="told, and "grog"="tilt". Furthermore, it was sometimes used for secrete communications such as Caesar cipher which was used for politic purpose. This was a method shifting alphabet three positions so that e 'a' is transformed into 'd', 'f' into 'i', 'z' into 'c'. For example, if there is a word “Term paper” it will be enciphered to “Whuo SdShu”. So, the plaintext would be term paper, ciphertext would be whuo sdshu and the key would be shifting alphabet for three positions. Even though this technique might be seen easy to decipher, majority was not able to read such codes in the time of Julio Caesar which made cipher powerful. After Caesar cipher the development of cryptology was unnoticeable. Nevertheless the French diplomat Blaise de Vigenère have developed polyalphabetic cipher in 16^th century. This cipher has been called “the unbreakable cipher” and actually has been unable to be broken for the four centuries. It has been deciphered by numerous researchers between the end of the 19^th century and the beginning of 20^th century. Another important, more modern, substitution cipher in the history of cryptography was The Hill cipher, a polygraphic substitution cipher. It was the first cipher which enabled use more than two symbols for a word.  Instead of substituting one letter for another letter, a polygraphic cipher one can substitute a word by more than a two group of words. This has made frequency analysis (a technique based on the fact that inside a text certain letters and combinations of letters occur with varying frequencies). attack ineffective since a word could be substituted by various words.

   

As time passed, when it became Second World War, people began to recognize the importance of machine in cryptography since machine was capable of making cipher more complicated and also easier to create cryptography. Therefore, Germans have made enigma machine which have played significant role win Second World War, which was used to encrypt and decrypt the cipher. As the war continued, however, allies were able to decrypt the cipher so that they could receive information about Germany. Therefore, some people believe that deciphering enigma was one of the main reasons of ally’s victory. As a result cryptography has played a significant role in the World’s History.

 

After Second World War, modern cryptology starts with the work that Claude Shannon have done during Second World War. He established the robust basis of cryptography by introducing the term called confusion and diffusion. First, confusion is a skill making the relationship between the key and the ciphertext complicated. On the other hand, diffusion is a skill spreading the influence of the plaintext over numerous ciphertexts. After introduction of two skills there were not significant developments at the beginning of the 1970s. However, in the mid 1970s there have been two major developments in the history of cryptography.  The first was the development of Data Encryption Standard by IBM which was used to develop secure electronic communication. Even though DES itself was not powerful enough, the alternatives made by using similar method was powerful enough to guarantee people secure communication. The second major development was development of new process, distributing cryptographic keys. It has raised the level of cryptography significantly since it have introduced asymmetric key algorithm to the world. Asymmetric key algorithm enables decrypting and encrypting key different. Therefore, we can designate one key of the pair as one private key and one public key(visible) so that no secure channel is needed for key exchange. So long as the private key stays secret, the public key can be widely known for a very long time without compromising security. In modern society, this is the ultimate version of the cryptography used in real life such as digital signatures and online purchasing.

Nacimera? American!

Nacimera? American!

121132 Jo Hyung Woo

      When people judge certain culture or a society, they do it in their own standards. Therefore, the evaluation differs from a person to person. This variety has derived from difference in personal experience, knowledge and the environment that the each panel was raised on. By their own standards, people sometimes criticize others and praise others. Therefore, there are some situations which seem extremely bizarre while others think it is not.

     For those people like me who are not familiar with metaphors, Body Ritual Among the Nacimera seemed like an article criticizing at Nacimeran culture. After having a lot of researches, however, I soon recognized that the article was actually focusing on American culture. When we spell the word nacimera backwards, it actually becomes the word American. Men scraping and lacerating the surface of the face with a sharp instrument meant shaving and women baking their heads in small ovens for about an hour meant drying hairs. Furthermore ancient code alludes that the doctor’s handwriting is illegible in prescription. There are other numerous metaphors that could be found in the book such as holy mouth man, medicine man etc. Actually, every sentences are metaphor of daily lives of American.

     After finishing the research, I was able to find out that the author was actually talking about the American culture. When I first read the article, I was not able to comprehend author’s intention since I was reading the passage based on by personal experience. There is a famous saying “ritual makes a society one, but it does not make societies one.” Rituals are an indigenous part of the society which differentiates society from others. Therefore, to fully understand others culture, one should approach in different perspective. The most important thing to understand other culture is to become free of bias which has been formed by rituals in one’s own society. As a matter of fact, to understand different culture, one should exclude prejudice and think outside of the box.