• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.206-212
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• 2006

Many image and video compression algorithms work by splitting the input image into blocks and producing variable-length coded bits for each block data. If variable-length coded data are transmitted consecutively, then the resulting coder is highly sensitive to channel errors. Therefore, most image and video techniques for providing some protection to the stream against channel errors usually involve adding a controlled amount of redundancy back into the stream. Such redundancy might take the form of resynchronization markers, which enable the decoder to restart the decoding process from the known state, in the event of transmission errors. The Error Resilient Entropy Code (EREC) is a well known method which can regain synchronization without any redundant information to convert from variable-length code to fixed-length code. This paper proposes an enhancement to EREC, which greatly improves its transmission ability for the compressed image quality without any redundant bits in the event of errors. The simulation result shows that the both objective and subjective quality of transmitted image is enhanced compared with the existing EREC at the same BER(Bit Error Rate).

• Journal of the Korean School Mathematics Society
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• v.14 no.3
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• pp.261-275
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• 2011

Seok-Jung Choi's Jisuguimundo mentioned as a brilliant legacy in the history of Korean mathematics had been cloaked in mystery for 300 years. In the meantime there has been some efforts to find solutions, and some particular answers were found, but no one achieved full success mathematically. By the way, H-alternating method showed that to find solutions of Jisuguimundo is possible, even though that method restricted magic number to 88~92 and 94~98. In this paper, $n{\times}n$ Jisuguimundo is defined, and it is showed that finding solutions of it is always possible in case of partition $({\upsilon}+1)+{\upsilon}+({\upsilon}+1)$ & co-partition ${\upsilon}+({\upsilon}+1)+{\upsilon}$, partition $({\upsilon}+1)+({\upsilon}-1)+({\upsilon}+1)$ & co-partition $({\upsilon}-1)+({\upsilon}+1)+({\upsilon}-1)$, partition $({\upsilon}+1)+({\upsilon}+2)+({\upsilon}+1)$ & co-partition $({\upsilon}+2)+({\upsilon}+1)+({\upsilon}+2)$, and partition $({\upsilon}+1)+({\upsilon}+3)+({\upsilon}+1)$ & co-partition $({\upsilon}+3)+({\upsilon}+1)+({\upsilon}+3)$. And It is suggested to find solutions of $n{\times}n$ Jisuguimundo could be used as a task for problem solving.

• Aerospace Industry
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• v.47
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• pp.56-59
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• 1997

''''95년 10월 3일 일본 나고야 근교의 미쓰비시 중공업 고마끼 공장에서 차기 전투기 FX-2의 처녀 비행이 여러 관계기관 사람들이 주목하는 가운데 실시되어 40여분간 비행하고 가볍게 내려 앉았다. 이보다 약 2개월 앞서 일본 신관이 참석한 엄숙한 의식을 치르고 미쓰비시 중공업 고마끼 공장에서 치러진 출고식에 이은 경사였다.

• Social Workers
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• no.9 s.53
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• pp.23-23
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• 2006

한국보건복지인력개발원은 지난 9월 5일 개발원 서래당에서 유시민 장관 초청 사회복지직 공무원 간담회를 개최하였다. 이날 간담회는 유시민 장관, 한국보건복지인력개발원 이태수 원장, 사회복지직 공무원 과정 수강생 40명 등이 참석한 가운데 사회복지직 공무원들이 가지고 있는 현안에 대해 대화를 나누는 시간으로 80여분가량 진행되었다.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.8
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• pp.377-384
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• 2007

With the advance of VLSI technology, the capacity and density of memories is rapidly growing. In this paper, We proposed a reallocation algorithm for faulty memory part to efficient reallocation with row and column redundant memory. Reallocation information obtained from faulty memory by only every test. Time overhead problem occurs geting reallocation information as every test. To its avoid, one test resulted from reallocation information can save to flash memory. In this paper, reallocation information increases efficiency using flash memory.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.1-3
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• 2002

백본 라우터에서의 최장 길이 프리픽스 검색(LPM: Longest Prefix Matching) 속도를 향상시키기 위해 활발히 연구된 방식들은 계산 량과 사용 메모리 량을 교환하는 방식들이다. 이러한 방식들은 성능향상을 위해서 대용량의 포워딩 테이블(Forwarding Table)을 캐쉬(Cache)에 저장할 수 있는 소용량 인덱스 테이블(Index Table)로 압축함으로써 고속 캐쉬 접근 회수와 그 계산량은 증가하는 대신 저속 메모리 접근 회수를 줄이는 방식이다.〔1〕본논문에서는 저속 메모리 사용량이 증가하는 반면 저속 메모리의 접근 빈도와 계산량을 동시에 감소시키는 FPLL(Fixed Prefix Length Lookup) 방식을 소개한다. 이 방식은 포워딩 엔트리(Entry)들을 프리픽스의 상위 비트(Bit)에 의해 그룹으로 나누고, 각 그룹에 속하는 엔트리들을 같은 길이로 정렬한다. FPLL에서의 LPM검색은 목적지 주소가 속하는 그룹들의 길이를 계산하여 검색할 최장 프리픽스의 길이를 미리 결정하고, 결정된 프리픽스를 키(key)로 하여 해시 테이블(Hash Table)로 구성된 포워딩 테이블에서 완전 일치(Exact Matching) 검색을 한다. 완전 일치 검색을 위해 같은 그룹에 속한 엔트리들을 정렬할 필요가 있는데 이 정렬을 위해 여분의 포워딩 테이블 엔트리가 생성된다. 3만개 엔트리를 갖는 Mae-West〔2〕 경우에, FPLL방식은 12만개 정도의 여분의 엔트리가 추가로 생성되는 대신에 1번 캐쉬 접근과 O(1)의 복잡도를 갖는 해시 테이블 검색으로 LPM 검색을 수행한다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.1
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• pp.216-224
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• 1999

In the paper we propose two recovery methods by adopting a rollback and/or roll-forward technique (S) to recover TMR failures in a TMR (structured ) system that is the simplest spatial redundancy. This technique is apparently effective to recovering TMR failures primarily caused by transient faults. The proposed policies carry out few reconfigurations at the cost of (minimal) time-overhead needed for those time-redundant schemes. The optimal checkpoint-interval vectors are derived for both methods through the likelihoods of all (possible) states of the system as well as the total execution-time. Consequently the effectiveness of our proposed policies is validated through certain numerical examples and simulations.

• The Journal of Korean Association of Computer Education
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• v.7 no.1
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• pp.37-44
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• 2004

Differentiated services network (DiffServ) aims to provide the same service to a group of connections that have similar Quality of Service requirements. One of the essential function to realize DiffServ is the traffic conditioning mechanism. The paper proposes the enhanced traffic conditioning mechanism which can assure the reserved rates of TCP and UDP flows and support fair distribution of excess bandwidth. The simulation results show that the new mechanism is rather insensitive of the effect of UDP against TCP throughput, and performs better both in terms of throughput assurance and fair distribution of excess bandwidth in case of well-provisioned and over-provisioned network environment.

• The KIPS Transactions:PartA
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• v.8A no.2
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• pp.81-90
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• 2001

As the rapid growth of Internet, computer systems are growing in its size and complexity. To meet high availability requirements for the systems, one usually uses both hardware and software fault tolerance techniques. To prevent failures of computer systems from software-aging phenomenon that come from long mission time, we adopt software rejuvenation method that stops and restarts the software in the servers intentionally. The method makes the systems clean and healthy state in which the probability of fault occurrence is very low. In this paper, we study how switchover time affects software rejuvenation of primary-backup server systems. Through experiments, we find that switchover time is an essential factor for deciding the rejuvenation policy.

• The Transactions of the Korea Information Processing Society
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• v.6 no.12
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• pp.3662-3674
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• 1999

This paper addresses some design issues for establishing the optimal number of spare units in array systems manufactured using fault-tolerant multichip modules(MCM's) for massively parallel computing(MPC). We propose a new quantitative approach to an optimal cost-effective MCM system design under yield and reliability constraints. In the proposed approach, we analyze the effect of residual redundancy on operational reliability of fault-tolerant MCM's. In particular, the issues of imperfect support circuitry, chip assembly yield and array topology are investigated. Extensive parametric results for the analysis are provided to show that our scheme can be applied to design ways using MCM's for MPC applications more efficiently, subject to yield and reliability constraints.