• Journal of the Korean Mathematical Society
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• v.36 no.1
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• pp.15-36
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• 1999

In this paper, we determine the dimension of the rectangular product of certain finite lattices. In face, if L1 and a L2 be finite lattices which satisfy the some conditions, then we have dim (L1$\square$L2) = dim(L1) + dim(L2) - 1.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.9
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• pp.1-8
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• 1993

In this paper, a new approach to the minimization of two-level Reed-Muller circuits is presented. In contrast to the previous method of using Xlinking operations to join two cubes for minimization. Cube selection method tries to select cubes one at a time until they cover the ON-set of the given function. A simple heuristic for selecting appropriate cubes is presented. In this heuristic, simply all cubes from the largest to the smallest are tried and whenever they decrease the number of remaining terms they are accepted. Since cubes once selected are not considered for a new selection, our method takes less time than other methods that need repetitive optimization process. The experimental results turned out to be improved in many cases compared to the best results in the literature.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.6
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• pp.104-110
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• 1995

In this paper, an effective method for the minimization of two-level Reed-muller expressions by cube selection whcih considers functional complexity is presented. In contrast to the previous methods which use Xlinking operations to join two cubes for minimizatio, the cube selection method tries to select cubes one at a time until they cover the ON-set of the given function. This method works for most benchmark circuits, but for parity-type functions it shows power performance. To solve this problem, a cost function which computes the functional complexity instead of only the size of ON-set of the function is used. Therefore the optimization is performed considering how the trun minterms are grouped together so that they can be realized by only a small number of cubes. In other words, it considers how the function is changed and how the change affects the next optimization step. Experimental results shows better performance in many cases including parity-type functions compared to pervious results.

• Smart Media Journal
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• v.5 no.4
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• pp.41-48
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• 2016

In mobile ad hoc networks(MANETs), all the nodes in a network have limited resources. Therefore, communication topology which has long lifetime is suitable for nodes in MANETs. And MANETs are exposed to various threats because of a new node which can join the network at any time. There are various researches on security problems in MANETs and many researches have tried to make efficient schemes for reducing network power consumption. Power consumption is necessary to secure networks, however too much power consumption can be critical to network lifetime. This paper focuses on energy efficient monitoring node distribution for enhancing network lifetime in MANETs. Since MANETs cannot use centralized infrastructure such as security systems of wired networks, we propose an efficient IDS node distribution scheme using minimum spanning tree (MST) method to cover all the nodes in a network and enhance the network lifetime. Simulation results show that the proposed algorithm has better performance in comparison with the existing algorithms.

• 한국전기화학회:학술대회논문집
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• 1998.12a
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• pp.153-166
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• 1998

Lithium ion Batteries commercially available since the early nineties in Japan are going to be more and more important for portable electronic devices and even EV applications. Today several companies around the world are working hard to join to market for Lithium secondary batteries. Based on the growing interest for commercial use of batteries also the materials have to be reviewed in order to meet large scale production needs. The requirements especially for electrolytes for lithium batteries are extremely high. The solvents and the lithium salts should be of highest purity. So the supply of these chemicals including packaging, transportation and storage but also the handling in production are critical items in this field. Frolic impurities are very critical for LiPF6 based electrolytes. The influence of water is tremendous. But also the other protic impurities like alcoholes are playing an Important role for the electrolyte quality. The reaction of these species with LiPF6 leads to formation of HF which further reacts with cathode materials (spinel) and anode. To understand the role of the protic impurities more clearly the electrolyte was doped with such compounds and was analyzed for protic impurities and HF. These results which directly show the relation between impurities and quality will be presented and discussed. In addition several investigations on different packaging materials as well as methods to analyze and handle the sensititive material will be addressed. These questions which are only partly discussed in literature so far and never been investigated systematically cover some of the key parameters for understanding of the battery chemicals. This investigation and understanding however is of major importance for scientist and engineers in the field of Lithium ion and Lithium polymer batteries.

• Journal of the Korean association of regional geographers
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• v.19 no.2
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• pp.340-351
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• 2013

International society has been making a lively discussion about natural disaster by climate change to mitigate natural hazard centering around intra-government association. This study dealt with a strategic mitigation and technical adaptation to support a habitual natural disaster region such as Bangladesh in terms of international cooperation for assistance to protect against the natural hazard. The land-cover on scale of one third of Bangladesh is situated lower than sea level that causes habitual flooding accident which gets increasing in the strengthen every single year. Most of people lives around exterior sea coast being faced with disaster of abnormal storm forming every three year cycle. Especially, the socio-economic status of the people in the coast is usually very low, and it need to get help from international cooperation aid. Therefor, the case study for the vulnerability of natural disaster in Bangladesh on geographical analysis is meaningful to join the international cooperation taking a part of role on technical support and education for adaptation of the natural disaster.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.16
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• pp.183-203
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• 2001

To accomplish international electronic commerce via the Internet, the most serious dilemma is the international payment system. The BBL is a secure and effective electronic commerce framework for the replacement of traditional paper documents by electronic messages via the Internet providing significant benefits in terms of cost savings, improved logistics and reduced errors in documentation. The most important legal obstacles in the BBL are how to secure authenticity, non-repudiation and message integrity as well as the status of negotiability equivalent to paper B/L. These kinds of functions may be carried out through the electronic title registry of the Bolero International Limited. The technical structure is supported contractually by the Bolero Rulebook. And other documents except B/L can be made out without any legal or technical problems. What are the handicaps of the BBL in its practical use at this time? I can summarize the current and expected problems as follows: First, the fee to join Bolero Association Limited is burdensome to sellers, buyers and trade related organizations all over the world. Second, the liability in errors or defaults in operating central data registry of Bolero International Limited is limited to U.S.$100,000. The amount is not sufficient to the many bulk cargo owners to cover the damages. Third, businessmen are used to traditional paper documents; therefore it takes much time for them to change their customs and practices. So the BBL and traditional papers would be used simultaneously for the time being. Finally, it is very important to incorporate the Rulebook, a multilateral contract binding on all users signed, in each domestic law, which will accomplish the uniform law basis.

• Korean Journal of Health Education and Promotion
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• v.23 no.3
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• pp.17-35
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• 2006

Objectives: This study was conducted to investigate the determining factors that have influence on elementary students who go without breakfast and identified their physical, mental and social health that may resulted by skipping breakfast. Methods: For data collection, total 855 elementary students at the 5th and 6th grade in an urban and a rural area were asked to join the survey using a self-administered questionnaire from March 25 to April 9, 2005. The data were analyzed through a series of statistical methods including frequency, percentage, chi-square$(X^2)$ test, t-test and multiple logistic regression analysis. Results: It was found that 24.0 % of respondents would skip breakfast, and influential socioeconomic factors on their skipped breakfast were economic level and mother's occupation. A group that has meals more with family everyday and a group that has breakfast served by mother as usual showed significantly low percentage of going without breakfast at statistical level(p<0.05). In case that other family members used to go without breakfast, there was a tendency to significantly high rate of skipped breakfast(p<0.01). And a group who got up early in the morning and a group who scored high points in the assessment of dietary habit showed significantly low percentage of skipped breakfast(p<0.01). In the result of multiple logistic regression analysis, the significant variables in urban area were economic level, person setting up breakfast, getting-up time and family members who would skip a meal. In rural area, meal-skipping family member, person setting up breakfast and dietary habit were significant variables(p<0.05). In physical influences according to skipping breakfast, students would skip breakfast had more stomach or dizziness(p<0.05). Depression score were higher and school life score were lower in group skipping breakfast, but not statistically significant. Conclusions: In conclusion, in order to reduce the rate of elementary students who often go without breakfast, it is favorable that they should be instructed in the importance of breakfast and the harm of skipped meal, so that they can cultivate positive living habits and dietary attitudes as well. And it is necessary that this health education cover not only students but also all of their family members(especially mother). Furthermore, it is necessary to develop systematic programs for them to get over environment factors.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.2
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• pp.281-292
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• 2017

It is demanded to promote research and development of cyber weapons system and core technology in response to the ongoing cyber attack of North Korea. In this paper, core technologies of the future cyber weapon system are developed and the factors affecting the realization timing of core technologies were analyzed. 9 core technology groups and 36 core technologies are derived. Afterwards, these core technology groups are compared to the operation phase of the joint cyber warfare guideline and the cyber kill chain of Lockheed Martin. As a result of the comparison, it is confirmed that the core technology groups cover all phases of the aforementioned tactics. The results of regression analyses performed on the degree of influence by each factor regarding the moment of core technology realization show that the moment of core technology realization approaches more quickly as factors such as technology level of the most advanced country, technology level of South Korea, technology transfer possibility from the military sector to the non-military sector(spin-off factor), and technology transfer possibility from the non-military sector to the military sector(spin-on factor) increase. On the contrary, the moment of core technology realization is delayed as the degree at which the advanced countries keep their core technologies from transferring decrease. The results also confirm that the moment of core technology realization is not significantly correlated to the economic ripple effect factor. This study is meaningful in that it extract core technologies of cyber weapon system in accordance with revision of force development directive and join cyber warfare guideline, which incorporated cyber weapon system into formal weapon system. Furthermore, the study is significant because it indicates the influential factor of the moment of core technology realization.

• The Journal of Industrial Distribution & Business
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• v.2 no.2
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• pp.39-45
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• 2011

The Korean distribution industry is gearing up for an endless competition. Greeting low growth era, less competitive parties will be challanged seriously for their survival. But for large discount stores, they have shown steady annual growth for years. However, because of the saturation for numbers of stores, the difficulty of gaining new sites, and the changes in the consumer's consumption behavior caused by the recession, now they are seeking for a new customers-based business formats. Accordingly, a large corporate comopanies made supermarkets which are belonged to affiliated companies of large corporate comopanies. They based on the strong buying power, focused on SSM(Super Super Market) ave been aggressively develop nationwide multi-stores. The point is that these stores are threatening at small and medium-sized, community-based private supermarkets. Private supermarkets and retailers, who are using existing old operation systems and their dilapidated facilities, are losing a competitive edge in business. Recent the social effects of large series of corporate supermarkets for traditional markets has been very controversial, and commercial media, academia, and industry associated with it have been held many seminars and public hearings. This may slow down the speed in accordance with the regulations, but will not be the crucial alternative. The reason for this recent surge of enterprise-class SSM up, one of the reasons is a stagnation in their offline discount mart, so they are finding new growth areas. Already in the form of large supermarkets across the country got most of the geographical centre point and is saturated with stages. Targeting small businesses that do not cover discount Mart, in order to expand business in the form of SSM is urgent. By contrast, private supermarkets are going to lose their competitiveness. The vulnerability of individual supermarkets, one of the vulnerabilities is price which economies of scale can not be realized so they are purchasing a small amount of products and difficult to get a quantity discount. The lack of organization and collaboration, and education which is not practical, caused the absencer of service-oriented situations. As a first solution, making specialty shops which are handling agricultures, fruits and vegetables and manufactured goods is recommended. Second, private supermarkets franchisees join the organization for the organization and collaboration is recomaned. It can be meet the scale of economy and can be formed a alternative business formats to a government. Third, the education is needed as a good service will get consumer's awareness. In addition, a psychological stores operating is also one way to stimulate consumer sentiment as SSM can't operate. Japan already has a better conditions of their lives through small chain expression. This study includes the vulnerabilities of private supermarkets, and suggests a competitiveness reinforcement strategies.