• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7C
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• pp.1015-1023
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• 2004

In order to protect an exchanged data, it is indispensable to establish a peer-to-peer key between the two communicating nodes. Pre-distributing keys among the nodes is unrealistic in Ad-Hoc network environment because of the dynamic nature of its network topology and the equal authority of its nodes. This paper presents a peer-to-peer key establishment scheme without pre-distributing keys in Ad-Hoc networks. The proposed scheme is based on the Diffie-Hellman key exchange protocol. Main idea is to prevent the falsification of Diffe-Hellman values using some elements of a hash chain. As a result, it is as safe as the underlying hash function against a man-in-the-middle attack. Simulation results have shown that the proposed scheme dramatically reduces the number of messages, and has relatively higher scalability, as compared with the key pre-distribution based scheme.

• Journal of Korean Library and Information Science Society
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• v.9
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• pp.33-61
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• 1982

It is an established fact that the university library is an important element in the higher education system. To keep abreast with the changing social environment industrial development and explosive increase of knowledge, the university library must also find new a n.0, pproaches to better serve the users in the university community. Also, on the part of university faculty, instructional methods must be improved from text book oriented education toward assignment oriented education. To facilitate effective teaching, the role of university library and its efficient use has become more important and indispensable. The objective of this study was to review the literature, and to find out current practice among students and professional librarians on the library instruction in order to find ways to strengthen and improve it. A specially designed questionnaire was used to survey current status. Results of the survey are summarized as follows; (1) Most university students received some guidance on library utilization as part of their freshman orientation program. However, it is found that the elementary nature of the guidance program was insufficient for their subsequent actual attempt to use. Students are not familiar with library organization, search procedure, and they lack basic knowledge on library service available to them. (2) Problem areas related to library instruction are insufficient amount of time allocated for the guidance program, big size of orientation program, and lack of interest on the part of students, etc. It is therefore recommended that the above mentioned problem areas be overcome through cooperative and concerted efforts among faculty members, professional librarians, and the university administration by increasing library instruction hours, improving the contents of program in its scope and depth to be practically useful. To sum up, the lecture oriented education should be shifted toward library oriented education by improved instruction program on library use.

• YAKHAK HOEJI
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• v.48 no.6
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• pp.384-390
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• 2004

Polyphenol oxidase-catalyzed oxidation of substrates (t-butylcatechol, 4-methylcatechol, chlorogenic acid, caffeic acid and pyrocatechol) were performed in the Ph range 4~8. Co ncentrations of substrate's major oxidation products were monitored by high performance liquid chromatograph. The nature and amounts of products formed were highly pH dependent. They also were ifluenced by kinds of substrates. Major oxidation product of 4-methylcatechol appeared the maxium value at pH 5, them of chlorogenic acid, caffeic acid and pyrocatechol at pH 6.0 and that of t-butylcatechol at pH 5~7. Time-dependent PPO activity was determined at $4^{\circ}C\;and\;30^{\circ}C$. PPO extracted by phosphate buffer containing triton X-114 (t-PPO) was more stable than PPO by phosphate buffer (b-PPO). The result of electrophoresis, at first PPO was showed only a band at 48 kd. After 1~3 days a partial degrade band was appeared in b-PPO and three partial degrade bands in t-PPO. No activity band was appeared in PPOs at $30^{\circ}C$ and b-PPO at $4^{\circ}C$ after 4 days. And a band (37 kDa) in t-PPO was remained finally and disappered. PPO from Perillae leaves has two activity bands at 48 and 37 kDa in previous paper. It was supposed that PPO in the leaves of Perilla frutescens was a protein having one molecular weight as 48 kDa. And 37 kDa protein, relatively proteolysis-resistant, was a proteolyzed form of a major form.

• The Journal of Natural Sciences
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• v.16 no.1
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• pp.111-128
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• 2005

This study was conducted under the theory of hermitage ever built from buddhist belief. Directing to hermitages within temples of Korea Jogye Order, we focused on the layout correspondence relationship among them. and 161 hermitages were the first object of the investigation. For the accomplishment of the research purpose, the general epitome and spatial specification through various literature studies, on-the-spot survey and personal communications with a lot of priests were made. As one of the basic surveys, the foundation year were thoroughly investigated, followed by the form of building, main buddha and hermitage name. The results obtained were summarized as follows : Forty five hermitages which are equivalent to twenty eight percent of total hermitages within the parish-level temples of Korea Jogye Order, were built in shilla Dynasty and twenty hermitages that are 12.4 percent of the total were constructed in Koryo Dynasty and thirty seven percent of the total were founded during both of dynasties. This fact makes us to consider that many of hermitages in those days were constructed with the simultaneity of principal temple foundation which means hermitage had responded the spirit of the times. Every hermitage has its main Buddha and this thing happened that each hermitage enshrines its main Buddha according to the thought which was developed with the Buddhism expansion and sutra that is in accordance with their own intention. .Basically a capital temple has differed in its central sanctum in accordance with resourceful sutra, and, at the same time, twenty seven in avatamsk sectenshrine for Sakyamuni as their sanction and eight for the Merciful Goddess and 42.7 percent for Chajang's hermitages. The name of hermitage not only represents its symbol but comprises the characteristic meaning of ascetic practice. 31.7 percent of the hermitages studies was found to have the names of relating to 'ascetic practice' or 'thought' followed by the 'nature' or 'environment' to 21.7 percent.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.221-229
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• 2011

Road design needs to ensure the economic justification and the preservation of nature by adapting road alignment to the natural terrain. Though current road design guideline only defines a flat and a mountainous terrain, classification including rolling terrain should be needed while considering the fact that about 25.8% of our land can be classified as rolling and the road design guideline of developed countries such as United States and Australia has a terrain classification including rolling in order to take a deep consideration on the natural environment. The study attempts to draw a criterion to classify the assumed three individual terrains in a quantitative way by using a index like the undulation of the original ground profile. The study carried out a case study based on a conceptual frame developed in the study as an approach to differentiate each terrain. As a result, the study suggests a criterion in that a flat terrain has less than 40 meters in the difference between the highest and the lowest point of original ground from 40 to 60 meters for rolling terrain, and greater than 60 meters for mountainous respectively.

• Journal of Convergence for Information Technology
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• v.8 no.1
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• pp.139-145
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• 2018

Ransomeware is a kind of malware. Computers infected with Ransomware have limited system access. It is a malicious program that must provide a money to the malicious code maker in order to release it. On May 12, 2017, with the largest Ransomware attack ever, concerns about the Internet security environment are growing. The types of Ransomware and countermeasures to prevent cyber terrorism are discussed. Ransomware, which has a strong infectious nature and has been constantly attacked in recent years, is typically in the form of Locky, Petya, Cerber, Samam, and Jigsaw. As of now, Ransomware defense is not 100% free. However, it can counter to Ransomware through automatic updates, installation of vaccines, and periodic backups. There is a need to find a multi-layered approach to minimize the risk of reaching the network and the system. Learn how to prevent Ransomware from corporate and individual users.

• Journal of the Korea Safety Management & Science
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• v.17 no.1
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• pp.75-84
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• 2015

Successful development of weapon systems requires a stringent verification and validation (V&V) process due to the nature of the weapons in which continual increase of operational capability makes the system requirements more complicated to meet. Thus, test and evaluation (T&E) of weapon systems is becoming more difficult. In such a situation, live fire tests appear to be effective and useful methods in not only carrying out V&V of the weapon systems under development, but also increasing the maturity of the end users operability of the system. However, during the process for live fire tests, a variety of accidents or mishaps can happen due to explosion, pyro, separation, and so on. As such, appropriate means to mitigate mishap possibilities should be provided and applied during the live fire tests. To study a way of how to accomplish it is the objective of this paper. To do so, top-level sources of hazard are first identified. A framework for T&E is also described. Then, to enhance the test range safety, it is discussed how test scenarios can be generated. The proposed method is based on the use of the anticipatory failure determination (AFD) and multiple event tree analysis (ETA) in analyzing range safety. It is intended to identify unexpected hazard components even in the environment with constraints. It is therefore expected to reduce accident possibilities as an alternative to the traditional root-cause analysis.

• Journal of the Mineralogical Society of Korea
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• v.29 no.2
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• pp.35-45
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• 2016

Clays, which are abundant in nature and eco-friendly, have been utilized throughout human history due to their characteristic physicochemical properties. Recently, a variety of clays such as montmorillonite, kaolinite, sepiolite and layered double hydroxide with or without chemical modification have been extensively studied for potential application in industries. Clays that possess a large specific surface area, high aspect ratio, nanometer sized layer thickness and controllable surface charge could be utilized as polymer fillers after appropriate chemical modifications. These modified clays can improve mechanical and gas barrier properties of polymer materials but also provide sustained antibacterial activity to polymer films. Furthermore, engineered clays can be utilized as scavengers for chemical or biological pollutants in water or soil, because they have desirable adsorption properties and chemical specificity. In this review, we are going to introduce recent researches on engineered clays for potential applications in future industries such as food packaging and environmental remediation.

• The Korean Journal of Malacology
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• v.28 no.3
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• pp.277-291
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• 2012

Aquaculture is challenged by a number of constraints with future efforts towards sustainable production. Global climate change has a potential damage to the sustainability by changing environmental surroundings unfavorably. The damaging parameters identified are water temperature, sea level, surface physical energy, precipitation, solar radiation, ocean acidification, and so on. Of them, temperature, mostly temperature elevation, occupies significant concern among marine ecologists and aquaculturists. Ocean acidification particularly draws shellfish aquaculturists' attention as it alters the marine chemistry, shifting the equilibrium towards more dissolved CO2 and hydrogen ions ($H^+$) and thus influencing signaling pathways on shell formation, immune system, and other biological processes. Temperature elevation by climate change is of double-sidedness: it can be an opportunistic parameter besides being a generally known damaging parameter in aquaculture. It can provide better environments for faster and longer growth for aquaculture species. It is also somehow advantageous for alleviation of aquaculture expansion pressure in a given location by opening a gate for new species and aquaculture zone expansion northward in the northern hemisphere, otherwise unavailable due to temperature limit. But in the science of climate change, the ways of influence on aquaculture are complex and ambiguous, and hence are still hard to identify and quantify. At the same time considerable parts of our knowledge on climate change effects on aquaculture are from the estimates from data of fisheries and agriculture. The consequences may be different from what they really are, particularly in the temperature region. In reality, bivalves and tunicates hung or caged in the longline system are often exposed to temperatures higher than those they encounter in nature, locally driving the farmed shellfish into an upper tolerable temperature extreme. We review recent climate change and following environment changes which can be factors or potential factors affecting shellfish aquaculture production in the temperate region.

• Journal of Digital Convergence
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• v.11 no.4
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• pp.91-99
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• 2013

While there is the active integration of various industries, a convergence of the software and knowledge service industries including software used in finance and counseling products is creating the necessity to include software industry utilization sectors aside from covering only software products and service production activities. Furthermore, to cope with the radical environment changes in the software industry when it comes to categorizing mobile and cloud computing areas into a software and classification system, we are at a point where there is a need to establish a directional nature on what should be included. In order to establish an integrated classification of newly introduced technologies, products and services, this paper aims to discover areas not included in the classification standard because of the ecological characteristics of the software. It also wants to differentiate the classification system and identify its incomplete areas such as the lack of connections within the system to ultimately establish such for newly surfacing software fields.