• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.207-209
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• 1996

The software of the midclass commuter flight simulation is running on multiprocessor/multitasking environments The software is consist of tasks which are periodically alive at a given interval. Each task communicates via shared memory. The data shared by tasks is divided by several block. Only one task, called producer, can produce data for a data block but several tasks, called consumers, can read data from the data block. Double buffer and conditional flag are used to implement a mutual exclusion which prevents the producer and consumers from accessing the same data block simultaneously.

• Annual Conference of KIPS
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• 2002.11a
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• pp.555-558
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• 2002

실시간 시스템의 개발 및 운영에 사용되는 실시간 운영체제는 여러 개의 태스크가 동시에 작업할 수 있는 멀티태스킹 환경과 각 태스크에 우선순위를 부여하여 가장 높은 우선순위의 태스크가 CPU 를 선점하는 스케줄링 방법, 태스크간 동기화 및 통신을 위한 메커니즘을 제공하고 있다. 그리고 여러 태스크들에 의해 사용되는 공유자원을 관리하기 위해 세마포어를 사용하여 태스크간에 동기화를 제공한다. 하지만 세마포어만으로 공유자원을 관리하게 되면 더 높은 우선순위의 태스크가 실행 준비 되어 있음에도 불구하고 상대적으로 낮은 우선순위의 태스크가 CPU 를 선점하는 우선순위 역전이 발생하여 실시간 운영체제의 핵심인 시간 결정성을 만족하지 못해 시스템에 심각한 문제를 발생 시킬 수 있다. 본 논문에서는 실시간 운영체제인 $iRTOS^{TM}$에서 우선순위 역전을 예방하기 위한 방법중 하나인 Priority Ceiling Protocol을 이용한 Mutual Exclusion Semaphore를 설계하고 구현한 내용을 기술한다.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.10
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• pp.1206-1216
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• 1999

이동 호스트란 시간과 공간의 제약 없이 필요한 기능을 수행하고, 또한 원하는 정보에 접근할 수 있는 휴대용 컴퓨터를 일컫는다. 이동 컴퓨팅 환경이란 이러한 이동 호스트들을 지원할 수 있도록 구성된 분산 환경이다. 따라서 이동 컴퓨팅 환경에서의 분산 알고리즘은 정적 호스트만을 고려한 기존의 분산 환경에서와는 다르게 이동 호스트의 여러 가지 특성들을 고려하여 제안되어야 한다. 즉, 이동 컴퓨팅 환경의 도래로 인하여 이동성과 휴대성, 그리고 무선 통신과 같은 특성들을 고려한 새로운 분산 상호 배제 알고리즘이 필요하다. 이제까지 이동 컴퓨팅 환경에서의 상호 배제 알고리즘은 토큰 링 구조에 기반을 두고 설계되었다. 토큰 링 구조는 이동 호스트들의 위치를 유지하기 위하여 높은 비용을 필요로 하는 단점을 가지고 있다. 본 논문에서는 균형 높이 트리(height-balanced tree)라는 새로운 모형을 제안함으로써 정적 분산 환경과 이동 분산 환경이 혼합된 환경에서 상호 배제 비용을 감소시킬 수 있는 새로운 알고리즘을 제안하며, 각 경우에 있어서의 비용을 산출하고 평가한다.Abstract The mobile host is a potable computer that carries out necessary functions and has the ability to access desirable informations without any constraints in time and space. Mobile computing environment is a distributed environment that is organized to support such mobile hosts. In that environment, distributed algorithms of which environment not only with static hosts but with mobile host's several properties should be proposed. With the emergence of mobile computing environments, a new distributed mutual exclusion method should be required to consider properties mobile computing system such as mobility, portability, and wireless communication. Until now, distributed mutual exclusion methods for mobile computing environments are designed based on a token ring structure, which have the drawbacks of requiring high costs in order to locate mobile hosts. In this paper, we propose a distributed mutual exclusion method that can reduce such costs by structuring the entire system as a height-balanced tree for static distributed networks and for networks with mobile hosts. We evaluated the operation costs in each case.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.182-189
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• 2010

This paper defines the quorum-based fault-tolerant mutual exclusion problem in a message-passing asynchronous system and determines a failure detector to solve the problem. This failure detector, which we call the modal failure detector star, and which we denote by $M^*$, is strictly weaker than the perfect failure detector P but strictly stronger than the eventually perfect failure detector ◇P. The paper shows that at any environment, the problem is solvable with $M^*$.

• The Transactions of the Korea Information Processing Society
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• v.4 no.9
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• pp.2221-2234
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• 1997

Distributed mutual exclusion algorithms have employed two approaches to achieve mutual exclusion and can be divided into two broad classes:token-based and permission-based. Token-based algorithms share a unique token among the nodes and a node is allowed to access its common resources if it possesses the token. Permission-based algorithms require one or more successive rounds of message exchanges among the nodes to obtain the permission to access the common resources. A hypercube architecture has earned wide acceptance in multiprocessor systems in the past few years because of its simple, yet rich topology. Accordingly, we study distributed permission-based mutual exclusion algorithms for hypercubes, and design a distributed permission-based mutual exclusion algorithm based on a new information structure adapted to the hypercubes. The new information structure is a request set of T-pattern from a logical mesh that is embedded into a hypercube. If a node wants to access the common resources, it sends request message to all nodes in the request set by Lan's multicast algorithm. Once the node receives a grant message from all nodes in the request set, it accesses the common resource. We evaluate our algorithm with respect to minimum round-trip delay, blocking delay, and the number of messages per access to the common resource.

• The Transactions of the Korea Information Processing Society
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• v.3 no.5
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• pp.1207-1214
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• 1996

We present an efficient decentralized, symmetric mutual exclusion algorithm for the hypercube architecture. The algorithm is based on the technique which embeds a mesh into a hypercube. We compare the performance of our algorithm with that of Gupta et al.'s algorithm. As a result of performance comparison, the minimum round-trip delay is equal to that of Gupta et al.'s algorithm, the average blocking delay is a little longer than that of Gupta et al.'s algorithm, and the number of messages per access to critical resource is fewer than that of Gupla et al.'s algorithm.

• Fashion & Textile Research Journal
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• v.4 no.4
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• pp.339-346
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• 2002

This study analyzed the works, introduced in the collections of Yohji Yamamoto in an aim to identify traditional aesthetic and design concepts. As the data to study the concept and expression of the designer, fashion photographs were gathered in a focus on collections since 1990's. The traditional aesthetic expressed in the works of Yohji Yamamoto were characterized by the external aesthetics and the internal aesthetics. The traditional aesthetic of external aesthetics were classified into the plasticity and the wearing, and those of internal aesthetics were divided into the moderation, expertness and aesthetic exclusion. The plasticity was extracted into line, form and color. The wearing was presented artist of purpose through the mutual text. The moderation was based on the moral goodness and the aesthetical beauty. The expertness represented the fitting method and mutual reaction of color. through the natural beauty. The aesthetic exclusion was expressed through simplicity, loftiness, and unbalance.

• Journal of Industrial Technology
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• v.18
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• pp.355-362
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• 1998

The deadlock detector is a DBMS sub-component that examines periodically whether system is in a deadlock state based on lock waiting information of transactions. The deadlock detector and transactions execute concurrently in a DBMS and read and/or write the lock waiting information simultaneously. Since the lock waiting information is a shared one, we need an efficient method guaranteeing its physical consistency by using mutual exclusion. In this paper, we propose a new method that effectively guarantees physical consistency of lock waiting information. Two primary goals of our method is to minimize the processing overhead and to maximize system concurrency.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.745-747
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• 2005

컴포넌트 기반 미들웨어에서 기본 단위를 이루는 컴포넌트가 특정 동일 목적을 위하여 그룹을 생성하고 정해진 서비스를 제공할 수 있다. 이렇게 생성된 그룹은 멤버들간에 리소스를 공유하는데, 이에 따른 상호배제(mutual exclusion) 문제가 그룹 멤버들 사이에서 발생한다. 커뮤니티 컴퓨팅과 같은 그룹 서비스에서는 환경이 다양하고 변화가 심하기 때문에 그룹의 구조 또한 생성, 삭제, 통합, 분리가 빈번히 일어난다. 본 논문에서는 분산 시스템에서의 상호배제 알고리즘을 컴포넌트 기반 미들웨어에서 생성된 그룹에 적용하고, 상호배제 기법이 적용된 상태에서 그룹이 통합하거나 분할될 때 상호배제의 일치성을 유지 할 수 있는 방법을 제시하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.9
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• pp.2927-2941
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• 2022

The primary task of machine fault diagnosis is to judge whether the current state is normal or damaged, so it is a typical binary classification problem with mutual exclusion. Mutually exclusive events and out-of-domain detection have one thing in common: there are two types of data and no intersection. We proposed a fusion model method to improve the accuracy of machine fault diagnosis, which is based on the mutual exclusivity of events and the commonality of out-of-distribution detection, and finally generalized to all binary classification problems. It is reported that the performance of a convolutional neural network (CNN) will decrease as the recognition type increases, so the variational auto-encoder (VAE) is used as the primary model. Two VAE models are used to train the machine's normal and fault sound data. Two reconstruction probabilities will be obtained during the test. The smaller value is transformed into a correction value of another value according to the mutually exclusive characteristics. Finally, the classification result is obtained according to the fusion algorithm. Filtering normal data features from fault data features is proposed, which shields the interference and makes the fault features more prominent. We confirm that good performance improvements have been achieved in the machine fault detection data set, and the results are better than most mainstream models.