• Journal of KIISE:Computer Systems and Theory
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• v.29 no.10
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• pp.561-572
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• 2002

Deadlock detection in distributed systems is considered difficult since no single site knows the exact information on the whole system state. This paper proposes a time-efficient algorithm for distributed deadlock detection and resolution. The initiator of the algorithm propagates a deadlock detection message and builds a reduced wait-for graph from the information carried by the replies. The time required for deadlock detection is reduced to half of that of the other algorithms. Moreover, any deadlock reachable from the initiator is detected whereas most previous algorithms only find out whether the initiator is involved in deadlock. This feature accelerates the detection of deadlock. Resolution of the detected deadlock is also simplified and precisely specified, while the current algorithms either present no resolution scheme or simply abort the initiator of the algorithm upon detecting deadlock.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.5_6
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• pp.257-267
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• 2004

Most algorithms for handling distributed deadlock problem in the generalized request model use the diffusing computation technique where propagation of probes and backward propagation of replies carrying dependency information between processes are both required to detect deadlock Since fast deadlock detection is critical, we propose an algorithm that lets probes rather than replies carry the information required for deadlock detection. This helps to remove the backward propagation of replies and reduce the time cost for deadlock detection to almost half of that of the existing algorithms. Moreover, the proposed algorithm is extended to deal with concurrent executions, which achieves further improvement of deadlock detection time, whereas the current algorithms deal only with a single execution. We compare the performance of the proposed algorithm with that of the other algorithms through simulation experiments.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.343-346
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• 2011

대부분의 퍼즐 게임에서 발생 할 수 있는 중요한 문제 중 하나는 교착상태 문제이다. 본 논문에서는 이러한 교착상태를 해결하기 위해 퍼즐 게임을 그래프 기법으로 나타낸 뒤, 이를 이용한 새로운 교착상태 발견 기법인 Cycle Detection을 제안한다. 기존의 기법들은 알고리즘을 수행하는데 너무 많은 시간이 걸리거나, 패턴에 대한 데이터베이스가 구축되어 있어야 하기 때문에 실시간으로 교착상태를 발견하기엔 문제가 있다. 본 논문에서는 이러한 문제점을 해결하기 위하여 탐색해야 하는 노드의 개수를 최대한 줄이는 Local search 기법과 Pruning 기법을 적용하여 퍼즐 게임을 플레이하는 동안 실시간으로 교착상태를 발견할 수 있는 기법을 제안한다. 본 기법은 성능을 평가하기 위해 실제 퍼즐게임 환경에서 알고리즘을 수행하고, 그 결과로 검색하는 노드의 개수와 검색 시간을 기존의 기법과 비교하여 성능향상을 확인하였다.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.5_6
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• pp.280-289
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• 2003

Deadlock recovery-based routing algorithms in wormhole networks have gained attraction due to low hardware complexity and high routing adaptability Progressive deadlock recovery techniques require a few dedicated resources to transmit deadlocked packets rather than killing them. Selection of deadlocked packets is primarily based on time-out value which should be carefully determined considering various traffic patterns or packet length. By its nature, current techniques using time-out accompany unignorable number of false deadlock detections especially in a heavy-loaded network or with long packet size. Moreover, when a deadlock occurs, more than one packet may be marked as deadlocked, which saturate the resources allocated for recovery. This paper proposes more accurate deadlock detection scheme which does not make use of time-out to declare deadlock. The proposed scheme reduces the probability to detect false deadlocks considerably. Furthermore, a single message is selected as deadlocked for each cycle of blocked messages, thereby eliminating recovery overheads.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.2
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• pp.49-54
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• 2005

This Paper Presents a non-blocking deadlock detection scheme with immediate cycle detection in multiprocessing systems. We assume an expedient state and a special case where each type of resource has one unit and each request is limited to one resource unit at a time. Unlike the previous deadlock detection schemes, this new method takes O(1) time for detecting a cycle and O(n+m) time for blocking or handling resource release where n and m are the number of processes and that of resources in the system. The deadlock detection latency is thus minimized and is constant regardless of n and m. However, in a multiprocessing system, the operating system can handle the blocking or release on-the-fly running on a separate processor, thus not interfering with user process execution. To some applications where deadlock is concerned, a predictable and zero-latency deadlock detection scheme could be very useful.

• Journal of The Korean Association of Information Education
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• v.2 no.2
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• pp.269-277
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• 1998

In most of the distributed deadlock detection algorithms using messages called probes, only a portion of the generated messages are effectively used, and hence the wasted probes cause heavy communication traffic. In this paper, a distributed deadlock detection algorithm is proposed which can efficiently detect deadlocks making use of those residue probes. Our algorithm is complete in the sense that they detect not only those deadlocks in which the initiator is involved as most other algorithms do, but all the other deadlocks that are present anywhere in a connected wait-for-graph. To detect all the deadlocks, the algorithms known to be most efficient require O(ne) messages, where e and n are the number of edges and nodes in the graph, respectively. The single execution of the presented algorithm can accomplish the same task with O(e) messages.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.489-491
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• 2000

본 논문은 ATM(Abstract Timed Machine)으로 명세된 실시간 시스템을 검증하기 위한 방법을 기술한다. ATM은 임무 위급 시스템인 실시간 시스템을 명세, 분석, 검증하기 위한 정형기법이다. ATM은 모드와 전이, 포트로 구성된다. 다른 정형기법과 비교하여 ATM은 소프트웨어의 순환공학 과정에서 사용하기 위해 설계되었다. 역공학 과정에서 ATM은 계산 논리 뿐만 아니라 실시간 시스템의 실제 소스코드에 있는 설계나 환경정보를 표현할 수 있다. 이러한 목적을 위해 ATM은 다양한 모드를 사용한다. ATM을 사용한 실시간 시스템의 검증은 도달성 그래프를 생성함으로써 수행한다. 도달성 그래프는 상태와 시간을 추상화되고 압축된 형태로 표현할 수 있으며 그 결과 시간 속성을 지닌 상태 공간을 감소시킬 수 있다. 또한 시스템의 교착상태를 쉽게 발견할 수 있다. 본 논문은 ATM과 실행 모델, 도달성 그래프, 검증을 위한 속성 등을 기술하며 이들을 다른 정형 기법들과 예제를 통하여 비교한다.

• Journal of KIISE:Software and Applications
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• v.28 no.3
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• pp.224-238
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• 2001

본 논문은 ATM(Abstract Timed Machine)으로 명세된 실시간 시스템을 검증하기 위한 방법을 기술한다. ATM은 임무 위급 시스템인 실시간 시스템을 명세, 분석, 검증하기 위한 정형기법이다. ATM은 모드와 전이, 포트로 구성되어 있으며 모드는 머신의 압축된 상태를 표현한다. 전이는 하나의 모드에서 다른 모드로의 전환을 나타내며 조건과 이벤트로 구성되어 있다. 포트는 ATM간의 상호작용을 위한 진입을 표현한다. 다른 정형기법과 비교하여 ATM은 소프트웨어의 순환공학 과정에서 사용하기 위해 설계되었다. 역공학 측면에서 볼 때 ATM은 계산 논리뿐만 아니라 실시간 시스템의 실제 소스코드에 있는 설계나 환경정보를 표현할 수 있다. 이러한 목적을 위해 ATM의 모드는 계산모드, 추상화 모드, 주제모드로 구분된다. 계산 모드는 코드 상에서의 논리와 계산을 나타내며 추상화 모드는 모드와 전이의 블록을 하나의 ATM으로써 표현한다. 대개의 경우, 이것은 코드 상에서의 블록을 ATM내 하나의 모드로 나타낼 때 사용한다. 주제 모드는 예외나 주기적 동작 등과 같은 다수의 ATM의 주제를 표현한다. 실시간 시스템을 검증하기 위해 시스템의 소스 코드는 역명세 과정을 통하여 ATM으로 표현된다. 검증은 ATM에 대한 도달성 그래프를 생성하는 것에 의해 수행된다. 도달성 그래프는 상태와 시간을 추상화되고 압축된 형태로 표현할 수 있으며 그 결과 시간 속성을 지닌 상태 공간을 감소시킬 수 있다. 또한 시스템의 교착상태를 쉽게 발견할 수 있다. 본 논문은 ATM과 실행 모델, 도달성 그래프, 검증을 위한 속성 등을 기술하며 이들을 다른 정형 방법들과 예제를 통하여 비교한다.수 있다. 모피우스는 헤더나 광고와 같은 불필요한 정보들을 제거하는 별도의 단계를 거치지 않으므로 wrapper를 빠르게 생성한다. 궁극적으로 모피우스는 새로운 웹 상점을 사용자가 자유롭게 추가, 삭제할 수 있는 환경을 제공한다.X>와 반응시킬 경우에는 반응식 c에 의거 진행됨을 예측할 수 있었다.의거 진행됨을 예측할 수 있었다.이 거의 산화되지 않았고, $700^{\circ}C$에서도 ZnS와 ZnO 상이 공존한 것으로 보아 SnO$_2$코팅이 ZnS의 산화를 억제하는 것으로 나타났다.pplied not only to the strike system in the RSC circle, but also to the logistics system in the SLC circle. Thus, the RSLC model can maximize combat synergy effects by integrating the RSC and the SLC. With a similar logic, this paper develops "A Revised System of Systems with Logistics (RSSL)" which combines "A New system of Systems" and logistics. These tow models proposed here help explain several issues such as logistics environment in future warfare, MOE(Measure of Effectiveness( on logistics performance, and COA(Course of Actions)

• The Korean Journal of Zoology
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• v.11 no.3
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• pp.83-84
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• 1968

An attempt was made to estimate the possible homology between human and bacterial DNA by the method of DNA-agar gel hybridization. HeLa DNA was embedded in the agar and $^14C-DNA$ Xanthomonas pelargonii was used as bacterial DNA for the sheared fragments. No homology between human and bacterial DNA was detected. If homology exists at all, it can be estimated from the sensitivity of the method and assuming some 1,000 nucleotide pairs per cistron, the not more than $2\times10^5$ base pairs or 200 bacterial cistrons would be preserved in human DNA, corresponding to less than 0.01 per cent of the total human genome.

• Journal of Popular Narrative
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• v.26 no.2
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• pp.191-219
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• 2020

This paper aims to identify the key features of the novel writing of Korean American immigrants and their meaning as one aspect of movement and contact occuring in the early modern period. The late return of the novels written by Nakcheong THUN in the 1930s is significant in that it restored ideas on the diversity of early modern mobility and confronted the history and culture of immigrants who were excluded from records and memories. Not only are these novels a product of the phenomenon of immigration, but they have also created a crack in the dichotomous perceptions of domination and subordination, center and periphery by envisioning it as a space that creates new history, culture, institutions and values. These novels treat the free love of intellectual, emotional, and ethical figures as a central event, demystifying Western free love, and at the same time, a society divided by various identities including class, race, and gender. The novels by Nakchung THUN visualize the active exchange between the immigrant and the indigenous community through the character of Jack, and imagines the heterotopia as a place where not for the immigrants' utopia, but for everyone's coexists. These novels have declared a kind of memory war on the subordinate and marginalized contact zones. The contact zones of the immigration area had been a place for experiencing extreme conflicts and discords, and at the same time, it has served as a place where various groups and communities are connected. The contact zones were common areas of solidarity and creation before being subject to division and occupation. The contact zones are far from the border or borderlands, so it is not a fixed and immutable deadlock. As a world free from central domination the contact zones have been a space that preoccupied history and culture through various encounters, and have been a community.