• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.5
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• pp.1-6
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• 2012

Unlike the past, modern urban intersections have dramatic growth in size and utilizations. As a result, continual traffic signal control is essential. Hence the individual or regional electrical blackout may bring about uncontrollable traffic congestion. Late summer of 2011 a regional blackout brought about traffic nightmare not including time and revenue loss associated with this disaster. Due to this disaster our national police agency and other government agencies are in process of introducing an UPS (uninterruptible power supply) system into essential intersections. This study estimates the power consumption necessary to sustain at least 2 continuous hours for a standard four-legged intersection. Prototype was studied using these standards. The field experiment of prototype showed positive results and was able to meet standard guidelines set forth. Prototype tested was able to meet standards in medium to large capacity of traffic size.

• Journal of The Korean Association of Information Education
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• v.15 no.3
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• pp.517-524
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• 2011

This paper presents a fast blind deconvolution method that produces a deblurring result from a single image in only a few seconds. The high speed of our method is enabled by considering the Discrete Fourier Transform (DFT), and its relation to filtering and convolution, and fast computation of Moore-Penrose inverse matrix. How can we predict the behavior of an arbitrary filter, or even more to the point design a filter to achieve certain specifications. The idea is to study the frequency response of the filter. This concept leads to an useful convolution formula. A Matlab implementation of our method usually takes less than one minute to deblur an image of moderate size, while the deblurring quality is comparable.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.6
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• pp.16-21
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• 2005

In paper, propose new partial resonance ZCS PWM controlled High frequency insulating Full-bridge DC/DC converter not using exciting current of high frequency transformer. It is compared with the existing principles in characteristics. It also realizes a widely stabilized ZVS operating using new ON-OFF control method at synchronized power rectification MOSFET of high frequency insulating transformer secondary. Besides, it is brought over 97[%] measurement efficiency by proposed DC-DC converts. It is proved effectiveness of new methods using DC UPS PWM rectifier as switching power supply.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.395-401
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• 2004

In the current high network-centralized computing and enterprising environment, it is getting essential to transmit data reliably at very high rates. Until now previous client/server model based NFS(Network File System) or AFS(Andrew's Files System) have met the various demands but from now couldn't satisfy those of the today's scalable high-performance computing environment. Not only performance but data sharing service redundancy have risen as a serious problem. In case of NFS, the locking issue and cache cause file system to reboot and make problem when it is used simply as ip-take over for H/A service. In case of AFS, it provides file sharing redundancy but it is not possible until the storage supporting redundancy and equipments are prepared. Lustre is an open source based cluster file system developed to meet both demands. Lustre consists of three types of subsystems : MDS(Meta-Data Server) which offers the meta-data services, OST(Objec Storage Targets) which provide file I/O, and Lustre Clients which interact with OST and MDS. These subsystems with message exchanging and pursuing scalable high-performance file system service. In this paper, we compare the transmission speed of gigabytes file between Lustre and NFS on the basis of concurrent users and also present the high availability of the file system by removing more than one OST in operation.

• The Korean Journal of Applied Statistics
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• v.16 no.2
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• pp.335-349
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• 2003

In this paper, we use Bayesian method for model selection of poisson vs. negative binomial distribution, and normal, double exponential vs. cauchy distribution. The fractional Bayes factor of O'Hagan (1995) was applied to Bayesian model selection under the assumption of noninformative improper priors for all parameters in the models. Through the analyses of real data and simulation data, we examine the usefulness of the fractional Bayes factor in comparison with intrinsic Bayes factors of Berger and Pericchi (1996, 1998).

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.6
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• pp.561-568
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• 2011

This paper describes the operation characteristic of a single-phase PFC converter with 1-switch voltage doubler strategy for single-phase double-conversion UPS. A single-phase PFC converter with 1-switch voltage doubler strategy needs a diode bridge and one bidirectional active switch. Thus it is possible to reduce the material cost. However, the study results of operation characteristic and controller design has not been known after the converter circuit was proposed. For the performance evaluation of PFC converter, single-phase 3kVA double-conversion UPS was tested. The performance of PFC converter is experimentally confirmed with followings - input current reference traking, input power factor correction.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.4
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• pp.100-105
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• 1998

This paper proposes a new control strategy of bidirectional uninterruptible power supply (UPS) with the performance of active power filter which compensates the harmonics and reactive power. With only one power stage, it is working simultaneously as the AC/DC rectifier/battery charger and DC/AC inverter to the operation of battery charging or back-up power supplying. Therefore the operation of the proposed system can be divided into the modes, such as the active power filter mode and the battery back-up power mode. And a novel closed-loop control strategy is used to calculate the reference current. The performance of the proposed 5[kVA] system is verified by the simulation and experimental results.

• Proceedings of the KIEE Conference
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• 2004.11d
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• pp.114-121
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• 2004

에너지 저장 방식은 양질의 전원이 요구되는 중요 부하를 보호하기 위해 꾸준히 개발되어 왔다. 그 중 현재 가장 관심 있는 분야 중 하나인 것은 bridging power 시스템이다. 이 bridging power 시스템은 25kW에서부터 2,500k범위까지 다양한 제품이 용도에 맞게 출시되고 있다. Bridging Power 방식들은 4가지로 크게 요약될 수 있다. 즉, 저/고속의 플라이휠, 배터리, ultra capacitors 및 magnetic storage 기술 등이다. 이 논문은 bridging power 시스템의 개요에 대해 설명하고, 주요 기능 감시 시스템의 특징 및 장/단점에 대해 기술했으며, 현재 EPRI와 EPRI PEAC과 함께 TVA Public Power Institute가 제공하는 R&D 활동에 대해 요약하였다.

• Journal of the Korea Society of Computer and Information
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• v.13 no.3
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• pp.131-138
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• 2008

This paper designed an Internet Convention e-Portal Information System through an experience and knowledges accumulated in case of information utilization regarding international meeting and conventions in knowledge information societies. Established the Non-stop Cluster system that was the H/W side, L4 and the applied system which was the 3-tier structure and Firewall, VPN, IDS/IPS security control system, S/W side, that utilized the WAS MVC architecture used WAS and a SOA architecture. an ASP EAI function. A user and a manager, designs and constructor, the user efficiency who were an evaluation basis of a Verification commissioner, Ubiquitous evaluated system stability. Information security anger, and evaluated former system and comparison. Therefore is evaluated to the excellent Convention e-Portal Systems that a performance 25.9% improvement consisted of compare with the existing Convention e-Portal Systems, and will contribute so as to be able to carry out-driven enemy role in development of the industrial our country Convention Ubiquitous Internet IT information Industry and International Society Conventions.

• 한국IT서비스학회:학술대회논문집
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• 2008.05a
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• pp.483-488
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• 2008

현대의 제 기술 시스템, 특히 IT 시스템의 서비스의 운용은 전기에너지와 불가분의 관계에 있다. 주요 IT 시스템 일수록 전기의 안정적인 공급을 위해 무정전전원 장치(UPS)를 두고 있다. 그러나 UPS는 상용전원(commercial power)에 문제가 생겼을 때 작동하지 않는 사례가 많이 보고되고 있으며 이로 인해 해당 기업 혹은 기관에서는 설비 및 데이터의 손상과 서비스의 중단으로 인해 기업브랜드 가치 손상과 많은 복구비용을 부담하게 된다. 본 논문에서는 UPS 및 정류기 등에 예비전력으로 사용되는 산업용 고정형 축전지설비에 대한 서비스의 배경, 축전지 관리, 도입 효과를 기술하고 이를 IT 서비스화 하는 것에 대해 기술한다. 또한 축전지설비 진단 기술 및 예비전력 관리시스템 설계 시 고려사항에 대해 기술하고 예비전력관리에 관한 시장, 사업모델, 향후 전망 그리고 시장활성화 방안에 대해서 제안한다.