• Korean Management Science Review
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• v.24 no.1
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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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• v.2 no.1
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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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• v.4 no.3
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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.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.7
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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.

• Journal of the Korea Safety Management & Science
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• v.19 no.1
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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.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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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.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.7 no.4
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• pp.159-168
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• 2012

The purpose of this study is to analyze the relationship of MOT and NPD performance in medium-sized manufacturing firms. To accomplish the purpose of the study, working hypotheses were established based on the literatures about the impacts of MOT factors on the NPD performance. The sample of this study is as follows : 12 electrical and electronics companies, 18 machine and engineering companies, 16 parts and materials companies. In order to verify hypotheses, the data were collected from team leader and manager of research center, R&D, and production department of these companies and the leader of R&D project team who all had experience in project or were participating in it in latest 3 years. The results of study were summarized as follows : First, in analysis on the reality of MOT factors in sample firms, will of top management level on the MOT was comparatively high but relatedness of business strategy and technology strategy, open R&D system, systematic time scheduling, management of R&D manpower, and developing and adapting PLM system were common level. Second, to improve NPD performance in medium-sized manufacturing firms, will of top management level on the MOT, relatedness of business strategy and technology strategy, open R&D system, systematic time scheduling, management of R&D manpower, and developing and adapting PLM system were intensively required.

• Journal of KIISE:Software and Applications
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• v.30 no.3_4
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• pp.293-307
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• 2003

Object-oriented development has been generalized, but object-oriented project planning and scheduling techniques have not been studied enough. Furthermore, it is difficult to apply the conventional software management techniques to object-oriented projects. Especially, the large scaled projects are increasing, but the project planing techniques for these large scaled projects have not been proposed enough. In this paper, we propose systematic techniques for OO based project scheduling. We suggest a 7 step-process for deriving the OO project schedule from the use-case diagram which is describing the functional requirements of the system. The proposed process includes identifying use-cases, drawing preliminary chart through interdependency analysis, identifying characteristics of each use case, determining the number of iteration, assigning use-cases to iteration, considering available resource and constraints, drawing revised PERT chart. Each step has the explanation of the input, output, and the guidelines needed to perform the step. The project scheduling technique proposed in this paper ran be used effectively in the planning phase which the purpose is to plan a development schedule to yield the high quality software in minimum time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.5
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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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• v.6 no.1
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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.