• Nuclear Engineering and Technology
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• 제49권5호
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• pp.989-995
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• 2017

Distributed Control System (DCS) communication networks, which use Fast Ethernet with redundant networks for the transmission of information, have been installed in digitalized nuclear power plants. Normally, failover tests are performed to verify the reliability of redundant networks during design and manufacturing phases; however, systematic integrity tests of DCS networks cannot be fully performed during these phases because all relevant equipment is not installed completely during these two phases. In additions, practical verification tests are insufficient, and there is a need to test the actual failover function of DCS redundant networks in the target environment. The purpose of this study is to verify that the failover functions works correctly in certain abnormal conditions during installation and commissioning phase and identify the influence of network failover on the entire DCS. To quantify the effects of network failover in the DCS, the packets (Protocol Data Units) must be collected and resource usage of the system has to be monitored and analyzed. This study introduces the use of a new methodology for verification of DCS network failover during the installation and commissioning phases. This study is expected to provide insight into verification methodology and the failover effects from DCS redundant networks. It also provides test results of network performance from DCS network failover in digitalized domestic nuclear power plants (NPPs).

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1992년도 봄 학술발표회 논문집
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• pp.79-84
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• 1992

An integrated design system has as its aim the incoporation of all the design processes, such as, planning, preliminary design, analysis, detailed design (mamber design), evaluation, and drafting into an unified software system. Successful implementation such a system could lead to major improvements in efficiency by eliminating duplication of data and efforts. reducing errors, saving design time, providing management support, and so on. This study presents a methodology for an computer-integrated design system for building structures, synthesizing algorithmic procedures and knowledge based expert systems on the network database. Network database, which was designed to store all information systematically during the design processes, provides centeral communication area between algorithms and expert systems. The conventional procedural codes automate the routine design phases such as structural analysis, whereas knowledge-based expert systems support designer's decisions at the creative design phases such as preliminary design etc. The user interface with interactive and batch modes controls the design phases and manages design information and activates the algorithms and the expert systems. The concept presented in this paper will contribute to the formulation of automated design systems for building structures.

• 한국콘텐츠학회논문지
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• 제9권9호
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• pp.235-242
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• 2009

이 연구는 생물테러리즘을 위기로 인식하고 생물테러리즘을 위기관리별로 어떻게 관리할 것인가에 대한 관리방안을 연구하는데 그 목적이 있다. 9.11 테러 이후 발생한 탄저균 테러는 전 세계에 생물병원체에 의한 공포감을 인식시켜 주었으며, 그 위험성이 강조된 사례이다. 본 연구결과 생물테러리즘 위기는 4단계로 구분하여 관리할 때 완화 및 예방단계에서는 테러리즘의 기준을 정하고, 대비를 하기 위하여 테러관련 법을 제정하고, 조기발견을 위한 감시체계를 확보해야 한다. 대비단계에서는 초동조치 팀을 편성하고 교육훈련을 통해 대응하는 요령을 숙달시켜야 하며, 각종 자원을 확보해야 한다. 대응단계에서는 숙달된 초동조치팀이 즉각 투입되어 현장 정리 및 확산을 방지해야 하며, 복구단계에서는 평가체제를 구축하여 조기에 정상적인 생활로 복귀할 수 있도록 조치해야 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권2호
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• pp.649-663
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• 2012

We propose a percolation based M2M networking architecture and its data transmission method. The proposed network architecture can be server-free and router-free, which allows us to operate routing efficiently with percolations based on six degrees of separation theory in small world network modeling. The data transmission can be divided into two phases: routing and data transmission phases. In the routing phase, probe packets will be transmitted and forwarded in the network thus multiple paths are selected and performed based on the constriction of the maximum hop number. In the second phase, the information will be encoded, say, with the fountain codes, and transmitted using the paths generated in the first phase. In such a way, an efficient routing and data transmission mechanism can be built, which allow us to construct a low-cost, flexible and ubiquitous network. Such a networking architecture and data transmission can be used in many M2M communications, such as the stub network of internet of things, and deep space networking, and so on.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권4호
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• pp.1866-1888
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• 2017

Efficient energy consumption in WSN is one of the key design issues for improving network stability period. In this paper, we propose a new Heterogeneity-aware Energy-efficient Clustering (HEC) technique which considers two types of heterogeneity - network lifetime and of sensor nodes. Selection of cluster head nodes is done based on the three network lifetime phases: only advanced nodes are allowed to become cluster heads in the initial phase; in the second active phase all nodes are allowed to participate in cluster head selection process with equal probability, and in the last dying out phase, clustering is relaxed by allowing direct transmission. Simulation-based performance analysis of the proposed technique as compared to other relevant techniques shows that HEC achieves longer stable region, improved throughput, and better energy dissipation owing to judicious consumption of additional energy of advanced nodes. On an average, the improvement observed for stability period over LEACH, SEP, FAIR and HEC- with SEP protocols is around 65%, 30%, 15% and 17% respectively. Further, the scalability of proposed technique is tested by varying the field size and number of sensing nodes. The results obtained are found to be quite optimistic. The impact of energy heterogeneity has also been assessed and it is found to improve the stability period though only upto a certain extent.

• 한국전기전자재료학회논문지
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• 제17권3호
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• pp.249-258
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• 2004

We investigated structural phases of potassium intercalated into carbon nanotubes using a structural optimization process applied to atomistic simulation methods. As the radius of carbon nanotubes increased, structures were found in various phases from an atomistic strand to multishell packs composed of coaxial cylindrical shells and in helical, layed, and crystalline structures. Numbers of helical atom rows composed of coaxial tubes and orthogonal vectors of a circular rolling of a triangular network could explain multishell phases of potassium in carbon nanotubes.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1997년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Fall 1997
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• pp.67-76
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• 1997

The seismic records of the main shock and two after shocks of the Yeongwol Earthquake are studied based on the phsase analysis. The travel time curves with 12 different possible phases are constructed to analysis the phases of the records. which were provided by KIGAM seismic network. The results of phase analysis show that 1) The main shock (Ms=4.5) shows clear Pn phase but two after shocks (Ms=4 and Ms=2.5) do not show Pn phase. 2) The Pg or PmP phases look as first arrival phase in the after shock records whose edicental distance is smaller or larger than 150 km. 3) It is very difficult to identity the phases related to the Conrad discontinuity even if the Conrad discontiuity arrival exists. 4) The record of GRE station located outside of the Kueongsan Basin shows different arrival time of Pn phase, P-S duration time and frequency compared with those of the other stations located within the Kyeongsan Basin.

• 천문학회지
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• 제47권6호
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• pp.293-302
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• 2014

Simultaneous time monitoring observations of $H_2O$ $6_{16}-5_{23}$, SiO J = 1-0, 2-1, 3-2, and $^{29}SiO$ ${\upsilon}=0$, J = 1-0 lines are carried out in the direction of the Mira variable star TX Cam with the Korean VLBI Network single dish radio telescopes. For the first time, the $H_2O$ maser emission from TX Cam is detected near the stellar velocity at five epochs from April 10, 2013 (${\phi}=3.13$) to June 4, 2014 (${\phi}=3.89$) including minimum optical phases. The intensities of $H_2O$ masers are very weak compared to SiO masers. The variation of peak antenna temperature ratios among SiO ${\upsilon}=1$, J = 1-0, J = 2-1, and J = 3-2 masers is investigated according to their phases. The shift of peak velocities of $H_2O$ and SiO masers with respect to the stellar velocity is also investigated according to observed optical phases. The $H_2O$ maser emission occurs around the stellar velocity during our monitoring interval. On the other hand, the peak velocities of SiO masers show a spread compared to the stellar velocity. The peak velocities of SiO J = 2-1, and J = 3-2 masers show a smaller spread with respect to the stellar velocity than those of SiO J = 1-0 masers. These simultaneous observations of multi-frequencies will provide a good constraint for maser pumping models and a good probe for investigating the stellar atmosphere and envelope according to their different excitation conditions.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(1)
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• pp.271-274
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• 2002

This paper presents tile efficient polling architecture for simple network management protocol (SNMP). Now a day, tile internet traffics have been increasing rapidly within a few years as the subscriber's network to connect internet is provided commonly. With this trend, the network management traffics also make the same phases. To provide numerous higher Quality services to the customers, the management traffic must be controlled within the permitted limit. This paper proposes the policy-based felling architecture for SNMP MIB with several parameters and suggests the data collecting layer architecture for the efficient polling.

• 제어로봇시스템학회논문지
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• 제18권7호
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• pp.644-649
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• 2012

This paper proposes the gait phase classifier using backpropagation neural networks method which uses the angle of lower body's joints and ground reaction force as input signals. The classification of a gait phase is useful to understand the gait characteristics of pathologic gait and to control the gait rehabilitation systems. The classifier categorizes a gait cycle as 7 phases which are commonly used to classify the sub-phases of the gait in the literature. We verify the efficiency of the proposed method through experiments.