• KSII Transactions on Internet and Information Systems (TIIS)
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• v.2 no.5
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• pp.222-238
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• 2008

In this paper, the random key pre-distribution scheme introduced in ACM CCS'02 by Eschenauer and Gligor is reexamined, and a generalized form of key establishment is introduced. As the communication overhead is one of the most critical constraints of any successful protocol design, we introduce an alternative scheme in which the connectivity is maintained at the same level as in the original work, while the communication overhead is reduced by about 40% of the original overhead, for various carefully chosen parameters. The main modification relies on the use of a two-level key pool design and two round assignment/key establishment phases. Further analysis demonstrates the efficiency of our modification.

• Journal of Acupuncture Research
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• v.33 no.2
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• pp.109-116
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• 2016

Objectives : Our primary objective lies in understanding the current landscape of translational research on acupuncture, moxibustion and pharmacopuncture. Methods : We searched our own selection of keywords of acupuncture, moxibustion and pharmacopuncture and translational research from three overseas databases (Pubmed, Scopus, Medicine) and four domestic databases (DBpia, KISS, Riss4u, Korea Med). Results : We have chosen 41 articles in total-40 articles on acupunture, 6 article on moxibustion(5 articles were duplicated in use in each category). Origin-wise, 48.8 %/24.8 %/17.0 % of our articles pool came from USA/China/Korea, respectively. UK, Austria, Thailand and Italy contributed the rest of our article pool. For those articles written in USA and China, review articles were the most common type. For the US articles, all 10 review articles were non-systematic reviews, while, for China's contribution, one out of 4 review articles were systematic review. Type-wise, our research pool's breakdown is as follows ; 17 review articles, 11 experimental research, 2 randomized controlled trials(RCT), 1 clinical trial, 4 conference reports, 1 letter, 1 study protocol and 4 uncategorized. Topic-wise, brain-neurology was most frequently referred with 8 articles, followed by parkinson's disease (3 articles) and epilepsy (2 articles). Conclusion : 1. In terms of research submission articles, Korea appears to be lacking translational research on acupuncture, moxibustion and pharmacopuncture, compared to USA and China, in our view. 2. Unlike the cases of USA and China, most of Korean translational research is limited to doing a T1 level of translational research. In order to bring bench-to-bedside to light. we believe, there should be more studies, and thereby a certain level of activation, to the T2 level of translational research in Korea. 3. Further, in our view there should be more efforts to improve article quality at the T1 level of translational research, which eventually becomes the fundamentals of the next level of research (i.e. T2 research), as well as to increase the number of research submissions, going forward.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.505-512
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• 2019

We propose a new method to monitor the water level of spent fuel pool in a nuclear power plant without electric power. We also analyze the performance and limitation of the proposed method. Our method is based on the reflected optical power at the end of optical fiber through a $1{\times}N$ optical coupler. We reveal that there is no problem to monitor the water level when using a $1{\times}8$ optical coupler. However, when a $1{\times}16$ optical coupler is used, only 15 out of 16 output ports can be used due to Rayleigh back-scattering. When a $1{\times}32$ optical coupler is used, only 25 out of 32 output ports can be used to monitor the water level.

• Journal of Environmental Health Sciences
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• v.27 no.4
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• pp.41-46
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• 2001

Trihalomethane(THMs) levels in drinking tap water, indoor swimming pool water and industrial effluent in Kunsan area were surveyed in this study. During experimental period, the monthly averages of THMs in drinking tap water from Keumkang wide-area supply ranged from 15$\mu\textrm{g}$/ι/to 50 $\mu\textrm{g}$ showing the highest level in summer. 3 indoor swimming pools showed the monthly average levels of THMs formation ranging from 8$\mu\textrm{g}$/ι/to 20$\mu\textrm{g}$/ι and the pool under public management seemed to maintain its water quality more stable than those under private management THMs concentrations in the effluents. discharged from 10 manufacturing companies, ranged from N.D. to 95$\mu\textrm{g}$/ι and it was estimated that the overall THMs level discharged front those manufacturing companies is not high, reflecting the traces recorded for most effluents. The composition ratios of individual THMs for industrial effluents showed a difference from those for drinking water and swimming pool water, along with their wide variations according to the company and relatively high composition ratios of Br substituents.

• The Journal of Korean Association of Computer Education
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• v.6 no.1
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• pp.95-107
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• 2003

For effective web-based teaching and learning, it is necessary to estimate. whether activities for it have attained to the learning goal. In HTML and file based item pool systems, it is difficult to manage, to create questions into various forms, and to share with other systems. It is also not easy to provide suitable questions according to the level of learners. On the contrary, XML document can systematically create a structured information. Since XML represents a structure with meaningful information units, it can be effectively used to manage, search, and store documents. Therefore, we designed and implemented a web-based item pool system based on XML, which can support leveled assessment by analyzing the level of learners and providing appropriate questions according to it.

• Nuclear Engineering and Technology
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• v.44 no.8
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• pp.847-854
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• 2012

Despite extensive research efforts, the mechanism of the nucleate boiling phenomena is still not clear. A direct numerical simulation of the boiling phenomena is one of the promising approaches in order to clarify its heat transfer characteristics and discuss their mechanism. Therefore, many DNS procedures have been developed based on recent highly advancing computer technologies. This brief review focuses on the state of the art in direct numerical simulation of the pool boiling phenomena over the past two decades. In this review, the fundamentals of the boiling phenomena and the bubble departure and micro-layer models are briefly introduced, and then the numerical procedures for tracking or capturing interface/surface shape such as the front tracking method, level set method, volume of fluid treatments, and other methods (Lattice Boltzmann method, phase-field method and so on) are briefly reviewed.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.650-653
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• 2013

IT기술의 발전과 인터넷의 끊임없는 확장은 정보유출과 같은 보안사고의 발생 빈도를 꾸준하게 증가 시키고 있다. 더불어 경제적 사회적 손실이 함께 증가됨에 따라 이를 예방하기 위한 목적으로 전세계 많은 기업과 국가기관에서 정보보호를 위한 법 제도를 제정하거나 강화하여 개정 하고 있다. 하지만, 국내 200만여 개 달하는 기업과 공공기관들 중에 극히 일부를 제외한 대부분은 관련 법 제도에 명시한 의무대상에 포함되지 않는다. 즉, 대부분의 기업이나 기관에서는 정보보호의 공백이 발생할 수 있다는 반증인 것이다. 따라서 본 연구에서는 이처럼 국가차원의 정보보호 공백이 될 수 있는 국내 대부분의 기업과 기관들을 대상으로 하여 조직에서 보유한 정보자산들에 대해 자가 정보보호수준을 진단하기 위한 방안으로 제시하는 복합평가항목Pool을 이용한 정보보호 수준진단 모델을 활용하여 비용절감 및 시간효율개선과 함께 정보보호 수준을 향상시키고자 한다.

• Advances in aircraft and spacecraft science
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• v.8 no.1
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• pp.31-51
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• 2021

Selective laser melting (SLM), one of the most widely used powder bed fusion (PBF) additive manufacturing (AM) technology, enables the fabrication of customized metallic parts with complex geometry by layer-by-layer fashion. However, SLM inherently poses several problems such as the discontinuities in the molten track and the steep temperature gradient resulting in a high degree of residual stress. To avoid such defects, thisstudy proposes a temperature thread multiscale model of SLM for the evaluation of the process at different scales. In microscale melt pool analysis, the laser beam parameters were evaluated based on the predicted melt pool morphology to check for lack-of-fusion or keyhole defects. The analysis results at microscale were then used to build an equivalent body heat flux model to obtain the residual stress distribution and the part distortions at the macroscale (part level). To identify the source of uneven heat dissipation, a liquid lifetime contour at macroscale was investigated. The predicted distortion was also experimentally validated showing a good agreement with the experimental measurement.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.148-153
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• 2009

Failure Mode Effects and Criticality Analysis (FMECA) is one of most widely used methods in modem engineering system to investigate potential failure modes and its severity upon the system. FMECA evaluates criticality and severity of each failure mode and visualize the risk level matrix putting those indices to column and row variable respectably. Generally, those indices are determined subjectively by experts and operators. However, this process has no choice but to include uncertainty. In this paper, a method for eliciting expert opinions considering its uncertainty is proposed to evaluate the criticality and severity. In addition, a fuzzy expert system is constructed in order to determine the crisp value of risk level for each failure mode. Finally, an illustrative example system is analyzed in the case study. The results are worth considering while deciding the proper policies for each component of the system.

• Nuclear Engineering and Technology
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• v.50 no.5
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• pp.627-638
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• 2018

This article describes an integrated Level 1-Level 2 probabilistic risk assessment (PRA) methodology to evaluate the radiological risk during postulated accident scenarios initiated during the decommissioning phase of a typical Mark I containment boiling water reactor. The fuel damage scenarios include those initiated while the reactor is permanently shut down, defueled, and the spent fuel is located into the spent fuel storage pool. This article focuses on the integrated Level 1-Level 2 PRA aspects of the analysis, from the beginning of the accident to the radiological release into the environment. The integrated Level 1-Level 2 decommissioning PRA uses event trees and fault trees that assess the accident progression until and after fuel damage. Detailed deterministic severe accident analyses are performed to support the fault tree/event tree development and to provide source term information for the various pieces of the Level 1-Level 2 model. Source terms information is collected from accidents occurring in both the reactor pressure vessel and the spent fuel pool, including simultaneous accidents. The Level 1-Level 2 PRA model evaluates the temporal and physical changes in plant conditions including consideration of major uncertainties. The goal of this article is to provide a methodology framework to perform a decommissioning Probabilistic Risk Assessment (PRA), and an application to a real case study is provided to show the use of the methodology. Results will be derived from the integrated Level 1-Level 2 decommissioning PSA event tree in terms of fuel damage frequency, large release frequency, and large early release frequency, including uncertainties.