• 경영과학
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• 제24권1호
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• pp.113-126
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• 2007

This paper deals with a mathematical approach for finding the time-fractions for the time-fraction based scheduling method in multimedia wireless networks. By introducing a constraint that regulates the performance fairness amongst users, we present a systematic method for harmonizing both the system and user performance. Numerical results show that the time-fraction based scheduling method reinforced with our scheme is very effective especially in multimedia environments.

• Journal of Computing Science and Engineering
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• 제2권1호
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• pp.74-97
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• 2008

A scheduling policy or a schedulability test is defined to be sustainable if any task system determined to be schedulable remains so if it behaves "better" than mandated by its system specifications. We provide a formal definition of sustainability, and subject the concept to systematic analysis in the context of the uniprocessor scheduling of periodic and sporadic task systems. We argue that it is, in general, preferable engineering practice to use sustainable tests if possible, and classify common uniprocessor schedulability tests according to whether they are sustainable or not.

• Journal of Construction Engineering and Project Management
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• 제4권3호
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• pp.53-59
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• 2014

Project managers are responsible to conduct project on time with least amount of costs and the most possible quality with respect to shortage of resources and environmental certainties. They have to make the best decision to reach such conflicting objects. In this study the project scheduling with multi goals-multi modes was planned in fuzzy conditions under resource constraints and expanded by fuzzy goal programing (FGP). The project cost was calculated by the price of renewable resources and the quality criteria were evaluated by the quality function deployment method (QFD). Finally the model was verified by a construction case study with 22 activities along with solving by GAMS. The results showed that this model could provide a systematic framework to facilitate the decision making process and made the project managers to be able to schedule the project closer to reality.

• 제어로봇시스템학회논문지
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• 제5권7호
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• pp.777-786
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• 1999

This work is concerned with the assignment of the desired eigenstructure for linear time-varying systems such as missiles, rockets, fighters, etc. Despite its well-known limitations, gain scheduling control appeared to be the focus of the research efforts. Scheduling of frozen-time, frozen-state controller for fast time-varying dynamics is known to be mathematically fallacious, and practically hazardous. Therefore, recent research efforts are being directed towards applying time-varying controllers. In this paper, ⅰ) we introduce a differential algebraic eigenvalue theory for linear time-varying systems, and ⅱ) we also propose an eigenstructure assignment scheme for linear time-varying systems via the differential Sylvester equation based upon the newly developed notions. The whole design procedure of the proposed eigenstructure assignment scheme is very systematic, and the scheme could be used to determine the stability of linear time-varying systems easily as well as provides a new horizon of designing controllers for the linear time-varying systems. The presented method is illustrated by a numerical example.

• 대한안전경영과학회지
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• 제19권1호
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• pp.181-189
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• 2017

The systematic management of technology infrastructure increasingly becomes critical as it represents the driving power for creating competitive advantage of nations and enterprises. In this sense, public facility and equipment, which is one major asset of technology infrastructure, should be managed effectively, systematically and efficiently to increase its overall equipment effectiveness. However, the manual and off-line communication was the unique way to communicate between the suppliers who provide facilities in the public sector and the customers who utilize the facilities in the industrial sector. This communication way caused invisibility of available usage time and increase of idle time, thereby decreasing the equipment effectiveness. This paper presents an web-based scheduling system that enables real-time collaboration and information sharing for increasing the equipment effectiveness. The designed system performs scheduling, facility management, order management and customer relationship management in an on-line platform, and carries out the processing and storing of relevant information in an integrated database. The paper includes a development approach to identify business process models and standardized system models by using object-modeling technique. The deliverable of the present work will contribute to increasing the equipment effectiveness by enhancing visibility, transparency and predictability by means of the integration with a legacy Enterprise Resource Planning.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.215-224
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• 2005

It is a fundamental requirement for the medium-sized manufacturing company with multiple-types of products and mixed process flows to have a real time feedback system for systematic production scheduling and process control to maximize the productivity and delivery achievement. However it is very inferior in actual condition to make infrastructure for a systematic production scheduling and process control in middle-sized manufacturing company, Proposed in this paper is an MES implementation approach for the successful construction of MES infrastructure, implementation and operation in medium-sized manufacturing companies with multiple-types of products and mixed process flows.

• 벤처창업연구
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• 제7권4호
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• pp.159-168
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• 2012

본 연구는 우리나라 중규모 제조기업에서 전기전자, 기계 및 엔지니어링, 부품 소재산업을 모집단으로 하고 이들 모집단에서 전기전자 부문 12개 기업, 기계 및 엔지니어링 부문 18개 기업, 부품 소재 부문 16개 기업 등을 표본으로 선정하여 이들 표본기업의 기술경영의 실태를 분석하고 기술경영의 펙터가 신제품개발 성과에 미치는 영향을 분석하였다. 분석 결과 기술경영 펙터 중에 CTO를 비롯한 최고경영층의 기술경영에 대한 의지는 비교적 높게 나타났으나 그 외 사업전략과 기술전략의 연계성, 개방형 연구개발 시스템, 체계적 일정관리, 연구개발 인력관리, 제품수명주기관리 시스템 개발과 적용 등은 보통보다 조금 높은 수준인 것으로 나타난 점으로 볼 때 이들 각 분야에 대한 중요성의 인식과 더불어 보다 많은 노력을 강구하여야 할 필요성을 알 수 있다. 또한 가설검정 결과에서 이들 중규모 기업들이 신제품개발성과(신제품개발 기간 단축, 제품수명주기에 부합, 제품경쟁력 증대)를 높이기 위해서는 기술경영에 대한 최고경영층의 확고한 의지와 지원이 따라야 하고 사업전략과 기술전략의 연계성을 반드시 고려하여야 하며 신제품개발 일정관리를 체계적으로 하고 개방형 연구개발 시스템을 강화하며 연구개발 인력관리와 특히 PLM시스템 개발과 적용을 동시에 수행하여야 함을 알 수 있다.

• 한국정보과학회논문지:소프트웨어및응용
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• 제30권3_4호
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• pp.293-307
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• 2003

객체지향 개발이 보편화되었지만 객체지향 프로젝트를 지원하는 소프트웨어 관리 기법에 대한 연구가 미흡하다. 또한, 기존의 소프트웨어 관리 기법을 객체지향 프로젝트에 적용하는 것 역시 어려움이 있다. 특히, 늘어가는 객체지향 기반의 대형 프로젝트에 적합한 프로젝트 계획 기법에 대한 연구가 미흡하다. 본 논문에서는 객체지향 프로젝트를 위한 관리 요소 중 스케줄링에 대한 체계화된 기법을 제안한다. 시스템의 기능적인 요구사항이 기술된 Use Case 다이어그램을 이용하여 객체지향 프로젝트 스케줄을 도출해 가는 과정을 Use Case 식별, 상호의존성 분석을 통한 초기 PERT 차트 작성, 각 Use Case의 특성 규명, Iteration 개수 결정, Iteration에 Use Case 할당, 유용한 자원과 제약 사항 고려, Revised PERT 차트 작성의 7 단계로 나누어 제안한다. 각 단계에 내한 입력 물과 중간 산출물, 그리고 수행 지침을 제시한다. 본 논문의 프로젝트 스케줄링 기법은 짧은 개발 기간 동안 고품질의 소프트웨어 생산에 목적을 둔 프로젝트 계획 단계에서 효율적인 기법으로 사용된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권5호
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• pp.691-708
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• 2010

An important issue of supporting multi-users with diverse quality-of-service (QoS) requirements over wireless networks is how to optimize the systematic scheduling by intelligently utilizing the available network resource while, at the same time, to meet each communication service QoS requirement. In this work, we study the problem of a variety of communication services over multi-media heterogeneous cognitive OFDM system. We first divide the communication services into two parts. Multimedia applications such as broadband voice transmission and real-time video streaming are very delay-sensitive (DS) and need guaranteed throughput. On the other side, services like file transmission and email service are relatively delay tolerant (DT) so varying-rate transmission is acceptable. Then, we formulate the scheduling as a convex optimization problem, and propose low complexity distributed solutions by jointly considering channel assignment, bit allocation, and power allocation. Unlike prior works that do not care computational complexity. Furthermore, we propose the FAASA (Fairness Assured Adaptive Sub-carrier Allocation) algorithm for both DS and DT users, which is a dynamic sub-carrier allocation algorithm in order to maximize throughput while taking into account fairness. We provide extensive simulation results which demonstrate the effectiveness of our proposed schemes.

• International Journal of Automotive Technology
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• 제6권1호
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• pp.71-77
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• 2005

This paper presents a systematic approach which determines the optimal period to minimize performance measure subject to the schedulability constraints of a real-time control system by formulating the scheduling problem as an optimal problem. The performance measure is derived from the summation of end-to-end response times of processed I/Os scheduled by the static cyclic method. The schedulability constraint is specified in terms of allowable resource utilization. At first, a uniprocessor case is considered and then it is extended to a distributed system connected through a communication link, local-inter network, UN. This approach is applied to the design of an automotive body control system in order to validate the feasibility through a real example. By using the approach, a set of optimal periods can easily be obtained without complex and advanced methods such as branch and bound (B&B) or simulated annealing.