• Journal of Korea Multimedia Society
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• v.9 no.1
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• pp.89-100
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• 2006

The introduction of GSMP open interface to OBS network can materialize to separate the transport plane and the control plane in OBS network. This makes the implementation of OBS switches simple and provides various flexibility. However, the introduction of open interface will cause the connection setup delay because of the additional processing overhead of open interface protocol. Also, in GSMP based network, the location of network management functions are not defined explicitly and the research result about the OBS network management is almost nothing. This paper proposes a parallel connection setup mechanism using centralized connection control server to minimize connection setup delay in OBS network with GSMP open interface and defines managed objects to support connection, configuration, performance, and fault management for the management of OBS network with GSMP open interface. This paper also proposes a distributed network management model, in which the above managed objects are distributed in a controller and an OBS switch according to network management functions. We verify the possibility of OBS control and network management by implementing network management function using proposed parallel connection setup mechanism and distributed network management model.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.2
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• pp.125-132
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• 2015

This paper is about analysis of UDRE monitoring method for Korean Satellite navigation system, which is the correction parameter of satellite measurements. New receiver clock bias and tropospheric delay error estimation method to make pseudo-range residual for UDRE monitoring is proposed. Saastamoinen model and Neill mapping function are used for estimate the tropospheric delay and EKF is used for estimgate the receiver clock bias. Through the satellite measurements and regional weather data received directly from the domestic is using for UDRE monitoring analysis, more suitable UDRE monitoring threshold can be deducted and it is expected to be utilized for fault detection technique of Korean Satellite Navigation System.

• Journal of the Korean Society for Railway
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• v.18 no.5
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• pp.439-446
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• 2015

The turnout system, which determines the direction of the train, is not only a key system but also a vulnerable system. Failure of this system may lead to a delay of the train or even casualties. In this light, it is necessary to precisely the conditions of the turnout system. Currently, ROADMASTER of Germany is used as a diagnostic system in Korea. However, a new diagnostic system should be developed for optimized operation of the turnout system with maintenance that is suitable for the Korean railway environment. In this paper, a Fault Tree Analysis for the representative faults of the turnout system is conducted and physical quantities, which can be the cause of the fault, are classified according to the component and function. Also, the measuring factors for the monitoring are derived and a decision making theory is suggested. On the basis of the results, we propose a new turnout diagnostic system that can provide more driverse and precise information than the conventional system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.8B
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• pp.482-491
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• 2007

This paper proposes a k-disjoint-path routing algorithm that provides energy efficient and reliable message transmission in wireless sensor networks. The proposed algorithm sends messages through a single path without the occurrence of critical events. However, it sends through k disjoint paths(k>1) under the occurrence of critical events. The proposed algorithm detects the occurrence of critical events by monitoring changing data patterns, and calculates k from a well-defined fault model and the target-delivery ratio. Our simulations reveal that the proposed algorithm is more resilient to node failure than other routing algorithms, and it also decreases energy consumption and reduces the average delay much more than multi-path and path-repair algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.648-654
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• 2010

Request operations and release operations occur repeatedly in resource allocation systems. The process requesting a resource acquires one by any priority-based mechanism, and returns the resource after some periods. In this system, resource failures lead to delay of resource allocation, or to termination of process holding the failed resource. To analyze this process effectively, this paper designs a probabilistic ACSR, a process algebra that extends ACSR with the probabilistic choice operation. The ability to express/analyze both request-release rates and failure-recovery rates is illustrated using probabilistic ACSR.

• The KIPS Transactions:PartA
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• v.11A no.3
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• pp.181-188
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• 2004

PDF(Parallel/Distributed Processing) is an internet-based parallel/distributed processing system that utilizes resources from hosts on the internet in idle state to perform large scale application through parallel processing, thus decreasing the total execution time. In this paper. do propose an adaptive method to be changed network environment at any time using realtime monitoring of host. It is found from experiments that parallel/distributed processing has better performance than its without monitoring as an adaptive strategy, which copy with task delay factor by overload and fault of network, be applicable to the cockpits of task allocation algorithm in PDP.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.121-121
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• 2000

반도체 산업의 발달에 따라 소자의 보다 빠른 동작 속도와 큰 집적도를 갖은 ULSI 구조를 얻기 위해, 새로운 금속배선 재료가 요구되고 있다. 기존의 금속 배선인 Al 및 Al 합금은 비교적 낮은 비저항과 박막형성의 용이함으로 인하여 현재까지 금속배선 재료로 사용되고 있으나, 고집적화에 따라 RC Time Delay와 Electromigration의 문제점을 들어내었다. 이러한 문제를 해결할 새로운 배선 재료로 Al보다 낮은 비저항을 가지며, electromigration 저항성을 갖는 Cu 금속배선 재료가 활발히 연구되고 있다. 본 실험에서는 (100) Si 웨이퍼를 기판으로 사용하였으며, 각층은 SiO2/Si3N4/EP Cu/Seed Cu/ TaN/SiO2/Si wafer 상태로 증착하였다. 확산방지막으로 TaN을 사용하였고, seed Cu는 sputtering 으로 증착하였으며, seed Cu 만으로 된 박막과 seed Cu + electro plating Cu로 구성된 박막을 제작하였다. 제작 완료된 박막은 N2 분위기에서 20$0^{\circ}C$ 120 min, 45$0^{\circ}C$ 60min 동안 열처리하여 Cu 박막의 조직 변화를 TEM 및 여러 분석방법을 이용하여 분석하였다. Plan-view TEM결과, 45$0^{\circ}C$, 60min 열처리함에 따라 결정립 성장이 일어난 것을 확인 할 수 있었다. 그러나, 성장후에도 twin boundary, stacking fault, dislocation, small defect 등은 여전히 남아 있음이 관찰된다. 그림 1(a)는 as-deposit 상태이며, 그림 1(b)는 45$0^{\circ}C$, 60min 열처리한 plan-view TEM 사진이다.

• Korean Management Science Review
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• v.10 no.1
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• pp.139-156
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• 1993

Various ATM switches have been proposed since Asynchronous Transfer Mode (ATM) was recognized as appropriate for implementing broadband integrated services digital network (BISDN). An ATM switching network may be evaluated on two sides : traffic performances (maximum throughput, delay, and packet loss probability, etc.) and structural features (complexity, i.e. the number of switch elements necessary to construct the same size switching network, maintenance, modularity, and fault tolerance, etc.). ATM switching networks proposed to date tend to show the contrary characteristics between structural features and traffic performance. The Knockout Switch, which is well known as one of ATM switches, shows a good traffic performance but it needs so many switch elements and buffers. In this paper, we propose an input and output buffered Knockout Switch for the purpose of reducing the number of switch elements and buffers of the existing Knockout Switch. We analyze the traffic performance and the structural features of the proposed switching architecture through a discrete time Markov chain and compare with those of the existing Knockout Switch. It was found that the proposed architecture could reduce more than 40 percent of switch elements and more than 30 percent of buffers under a given requirement of cell loss probability of the switch.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.6
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• pp.898-904
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• 2017

DFT(Discrete Fourier Transform) is one of the most widely used method to estimate the phasor of a relaying signal. The harmonics are eliminated by the DFT. However, high frequency components, except for harmonics, are not removed and cause an error in DFT-based phasor estimation process. This paper suggests high frequency noise reduction method by using a newly designed low-pass filter to estimate a signal phasor. When selecting a stop-band cut-off frequency of the low-pass filter, high frequency components generated by faults are considered. To reduce the phasor estimation delay caused by a low-pass filter, this paper proposes a low-pass filter whose settling time is reduced. An adverse effect of high frequency noise on DFT-based phasor estimation is reduced. To evaluate the performance of the proposed method, signals which are collected under a fault condition at a 345[kV] transmission system modeled by EMTP-RV are used.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.10
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• pp.801-807
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• 2009

In this paper, we propose a novel shoot-through protection circuit and pulse generator for half-bridge driver IC. We designed a robust half-bridge driver IC over a variation of processes and power supplies. The proposed circuit is composed a delay circuit using a beta-multiplier reference. The proposed circuit has a lower variation rate of dead time and pulse-width over variation of processes and supply voltages than the conventional circuit. Especially, the proposed circuit has more excellent pulse-width matching of set and reset signals than the conventional circuit. Also, the proposed pulse generator is prevented from fault operations using a logic gate. Dead time and pulse-width of the proposed circuit are typical 250 ns, respectively. The variation ratio is 68%(170 ns) of maximum over variation of processes and supply voltages. The proposed circuit is designed using $1\;{\mu}m$ 650 V BCD (Bipolar, CMOS, DMOS) process parameter, and the simulations are carried out using Spectre simulator of Cadence corporation.