• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1311-1317
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• 2010

In this paper, for a uplink space division multiple access system named cooperative spatial multiplexing(CSM), radio resource management(RRM) algorithms are proposed based on sharing uplink channel information among a serving base station(BS) and interfering BSs in a uplink coordinated wireless communication system. A constrained maximum transmit power algorithm is proposed for mobile station(MS) to limit uplink inter-cell interference(ICI). And joint scheduling algorithm among coordinated BSs is proposed to enhance uplink capacity through ICI mitigation by using channel information from interfering BSs. It is shown that the proposed RRM algorithm provides a considerable uplink capacity enhancement by effective ICI mitigation only with moderate complexity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9B
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• pp.591-595
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• 2005

In this paper, we propose the fairness improvement leaky bucket (PILB) algorithm as a traffic policing mechanism. In the proposed algorithm, there is a cell buffer for every ATM connection in order to store date cells. Network decides whether an ATM connection obeys the contracted traffic parameter, and stores data cells in the cell buffer if the connection obeys but is considered as violated the contract due to temporary lack of network resource. By using the proposed algorithm, we can obtain the statistical multiplexing gain that is the superiority of packet switching network. Moreover, when a connection tries to transmit more data cells by violating the contracted traffic parameters, the connection is prevented from using excess network resource, which incurs all connections sharing network resource fairly. The performance of the proposed FILB algorithm is investigated by using the simulation. The result shows that the proposed algorithm provides superior performance and all connections within a group share network resource fairly. The proposed algorithm can be applied not only the ATM network but also IP network.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06a
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• pp.211-213
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• 2006

실시간으로 변화하는 컴퓨터 통신 환경에서 멀티미디어 응용 프로그램은 QoS를 만족하기 위해 안정적으로 튜닝 되고 재구성되는 것이 필요하다. 그러나 안정적으로 QoS를 보장하는 것은 응용 프로그램의 자원 예약이나 실시간 보장과 같은 메카니즘을 제공하지 않은 일반적인 목적의 시스템 상에서 수행될 때 많은 어려움을 가지게 된다. 특히, 예측 불가능한 개방형 환경에서 최우선 자원 할당에 의해 발생되는 자원의 유효성에 대응하기 위해 QoS 적응은 수행되어야 한다. 그러나 적응을 언제, 어떻게 조정해야 하고 폭 넓은 범위에서 응용 프로그램에 어떻게 적용시킬지를 알기 위해 일반적인 알고리즘을 제시해야할 필요가 있다. 이러한 목적을 위해, 본 논문에서는 멀티미디어 어플리케이션의 파라미터를 모델링하고, 파라미터간의 관계를 정량적으로 얻기 위해 계층적 QoS 프로빙 알고리즘을 적용한다. 이것을 기반으로 설계된 베이지안 네트워크를 이용하여 불확실한 정보를 확률값으로 처리함으로써 적응 행동을 예측하도록 한다. 마지막으로 실제 실험을 통해 제안된 미들웨어의 유용성을 확인한다.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.4
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• pp.31-41
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• 2009

IEEE 802.11e proposed by IEEE 802.11 working group to guarantee QoS has contention based EDCA and contention free based HCCA. HCCA, a centralized polling based mechanism of 802.11e, needs a scheduling algorithm to allocate the network resource efficiently. The existing standard scheduler, however, is inefficient to support for QoS guarantee for real-time service having VBR traffic. To improve these limit, in this paper, we First, we propose priority polling algorithm which additionally considers the size of MSI and TXOP based on EDD algorithm to increase number of QSTAs. We also propose a dual token bucket TXOP allocation algorithm to reduce congestion caused by stations which enters network with considerable delay variance. TSPEC parameters, Maximum Burst Size (MBS) and Peak Data Rate (PR), are applied to design depth and token generation rate of two buckets. Simulation results show that the proposed algorithm has much higher performance compared with reference and SETT-EDD scheduler in terms of throughput and delay.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.4
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• pp.106-113
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• 2008

본 논문에서는 유한용량 재진입 생산라인에서의 스케줄링 문제에 대한 유전자적 접근 방법을 제안하였다. 알고리즘에서 사용되는 염색체의 구조는 워크스테이션의 버퍼레벨에 대한 모든 가능한 경우를 고려하여 정의되었으며, 염색체의 각 유전자에는 그에 대응되는 시스템 상태에서 우선 순위를 갖는 작업 단계의 값이 할당되도록 하였다. 또한, 제안된 알고리즘의 구현 방법으로서 워크스테이션의 버퍼와 프로세싱 자원을 할당할 때 작업 간 우선 순위를 고려하는 동시에 각 워크스테이션의 로컬 유휴 상태를 지양하는 우선순위 기반 랜덤화 정책 알고리즘을 제안하였다. 실험을 통하여 제안된 알고리즘의 성능을 평가하였으며, 기존에 무한용량 재진입 생산라인 스케줄링 문제에 많이 이용되었던 휴리스틱과 비교하여 보다 효율적임을 보였다.

• The Transactions of the Korea Information Processing Society
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• v.7 no.10
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• pp.3055-3063
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• 2000

In this paper, a task duplication based heuristic scheduling algorithm is proposed to solve the problem of task scheduling on Shared Memory Multiporcessors (SMM). The proposed algorithm pre-allocates network resources so as to avoid potential communication conlhct, and the algorithm uses heuristies to select duplication tasks so as to recuce of a multiprocessors, and generates scheduling accorting to the available number of processors ina system. The proposed algorithm has been applied to some practical task graphs in the simulation, and the results show that the proposed algorithm achieves considerable performance improvement, in respect of schedule length.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.4
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• pp.443-454
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• 1999

최소 여유시간 우선(Least-Laxity-First)스케쥴링 알고리즘은 여유시간이 작은 태스트가 높은 우선순위를 갖는 동적 우선순위 스케줄링 방법으로서 단일프로세서 시스템에서 최적임이 증명되었다. 그러나, 이 알고리즘은 최소 여유시간을 가진 태스크가 여러 개 존재하여 여유시간 충돌이 발생한 경우 이 태스크들 간에 빈번한 문맥교환이 발생하게 되는 문제점이 있어 실용적이지 못하다. 본 논문에서 제한하는 최소 여유시간 우선 기반의 최소선점을 갖는 스케줄링 알고리즘(Least-Laxity-First with Minimum Preemption 또는 LLF/MP)은 여유시간이 충돌했을 때에 문맥교환을 최소화함으로써 최소 여유시간 우선 스케줄링 알고리즘의 단점을 해결하였다. LLF/MP 스케줄링 알고리듬은 불필요한 문맥교환을 줄임으로써 시스템 오버헤드로 인한 시스템의 성능 저하를 방지할 수 있고 보다 많은 시스템 자원을 예측 불가능한 비주기적 태스크에게 할당할수 있다.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.7
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• pp.370-379
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• 2006

Computational grid provides the environment which integrates v 따 ious computing resources. Grid environment is more complex and various than traditional computing environment, and consists of various resources where various software packages are installed in different platforms. For more efficient usage of computational grid, therefore, some kind of integration is required to manage grid resources more effectively. In this paper, a global scheduler is suggested, which integrates grid resources at meta level with applying various scheduling policies. The global scheduler consists of a mechanical part and three policies. The mechanical part mainly search user queues and resource queues to select appropriate job and computing resource. An algorithm for the mechanical part is defined and optimized. Three policies are user selecting policy, resource selecting policy, and executing policy. These can be defined newly and replaced with new one freely while operation of computational grid is temporarily holding. User selecting policy, for example, can be defined to select a certain user with higher priority than other users, resource selecting policy is for selecting the computing resource which is matched well with user's requirements, and executing policy is to overcome communication overheads on grid middleware. Finally, various algorithms for user selecting policy are defined only in terms of user fairness, and their performances are compared.

• Journal of the Korea Society for Simulation
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• v.32 no.4
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• pp.41-58
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• 2023

As naval warfare changes to composite warfare that includes simultaneous engagements against surface, underwater, and air enemies, performance and tactical analysis are required to respond to naval warfare. In particular, for practical analysis of composite warfare, it is necessary to study engagement simulations that can appropriately utilize the limited performance resources of the detection system. This paper proposes a DEVS (Discrete Event Systems Specifications)-based simulation model for composite warfare analysis. The proposed model contains generalized models of combat platforms and armed objects to simulate various complex warfare situations. In addition, we propose a detection performance allocation algorithm that can be applied to a detection system model, considering the characteristics of composite warfare in which missions must be performed using limited detection resources. We experimented with the effectiveness of composite warfare according to the strength of the detection system's resource allocation, the enemy force's size, and the friendly force's departure location. The simulation results showed the effect of the resource allocation function on engagement time and success. Our model will be used as an engineering basis for analyzing the tactics of warships in various complex warfare situations in the future.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.2
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• pp.156-163
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• 2004

This paper is concerned with coordinated collaboration of multiagent system in which there exist multiple agents which have their own set of skills to perform some tasks, multiple external resources which can be either used exclusively by an agent or shared by the specified number of agents at a time, and a set of tasks which consists of a collection of subtasks each of which can be carried out by an agent. Even though a subtask can be carried out by several agents, its processing cost may be different depending on which agent performs it. To process tasks, some coordination work is required such as allocating their constituent subtasks among competent agents and scheduling the allocated subtasks to determine their processing order at each agent. This paper proposes a genetic algorithm-based method to coordinate the agents to process tasks in the considered multiagent environments. It also presents some experiment results for the proposed method and shows that the proposed method is a useful coordination collaboration method of multiagent system.