• ETRI Journal
• /
• 제39권3호
• /
• pp.364-372
• /
• 2017

For the reliability of controllers in a software defined network (SDN), a dynamic and self-learning schedule method (DSL) is proposed. This method is original and easy to deploy, and optimizes the combination of multiple controllers. First, we summarize multiple controllers' combinations and schedule problems in an SDN and analyze its reliability. Then, we introduce the architecture of the schedule method and evaluate multi-controller reliability, the DSL method, and its optimized solution. By continually and statistically learning the information about controller reliability, this method treats it as a metric to schedule controllers. Finally, we compare and test the method using a given testing scenario based on an SDN network simulator. The experiment results show that the DSL method can significantly improve the total reliability of an SDN compared with a random schedule, and the proposed optimization algorithm has higher efficiency than an exhaustive search.

• Journal of Biosystems Engineering
• /
• 제38권1호
• /
• pp.18-24
• /
• 2013

Purpose: This study was conducted to develop an optimal combine scheduling program using Max-Coverage algorithm which derives the maximum efficiency for a specific location in harvest seasons. Methods: The combine scheduling program was operated with information about combine specification and farmland. Four operating types (Max-Coverage algorithm type, Boustrophedon path type, max quality value type, and max area type) were selected to compare quality and working capacity. Result: The working time of Max-Coverage algorithm type was shorter than others, and the total quality value of Max-Coverage algorithm and max quality value type were higher than others. Conclusion: The developed combine scheduling program using Max-Coverage algorithm will provide optimal operation and maximum quality in a limited area and time.

• 경영과학
• /
• 제20권2호
• /
• pp.33-43
• /
• 2003

In this paper we applied dynamic programming to determining work schedule type. In dynamic programming formulation, each day during a planning horizon represents a stage for which a decision is made. The alternatives are given by work schedule types that combine regular time, overtime, additional shift, and so on. In this case, their associated return function is labor cost. The state is defined as the amount of work time allocated to stage 1, stage 2,…, and current stage. A case study for a real manufacturing company was performed to apply dynamic programming to scheduling daily work hours during a week. The case study showed that total cost of our solution derived from dynamic programming decreased by about 6％ as compared with the solution obtained from the previous method.

• 한국콘텐츠학회논문지
• /
• 제6권7호
• /
• pp.50-57
• /
• 2006

대표적인 개인용 단말기인 휴대폰은 하드웨어의 독립성을 확보할 수 있는 WIPI라는 새로운 플랫폼으로 표준화되고 있어 응용 개발의 가속도를 더하고 있다. 본 논문에서는 이메일과 아바타를 접목시켜 사용자가 이메일을 보내고 받는데 있어서 아바타를 통해 자신을 나타내 보일 수 있도록 WIPI 기반으로 구현하였고, 또한 일반적인 이메일 응용 프로그램들이 이메일과 일정 관리 프로그램을 같이 가지고 있듯이, 본 논문에서도 일정 관리 프로그램을 이메일과 통합하여 쓸 수 있도록 구현하였다. 이 구현 프로그램의 유용성을 더하기 위해, 일정을 통보하기 위한 방법으로 SMS 문자 서비스를 이용하였고, 휴대폰에서 입력한 일정을 PC 기반의 Microsoft Outlook의 일정과 동기화 할 수 있도록 개발하였다.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2019년도 춘계학술발표대회
• /
• pp.79-81
• /
• 2019

Collecting data in wireless sensor networks in minimum time is a traditional problem which is known NP-hard. Previous studies built the schedule using the node-based or link-based metrics to prioritize the transmissions. In this work, we combine the effect of both metrics to obtain a smaller aggregation time. We compare our work with state of the art schemes and report the improvement.

• 산업경영시스템학회지
• /
• 제30권2호
• /
• pp.44-50
• /
• 2007

This paper deals with the problem of scheduling jobs and rate-modifying activities on parallel machines. A rate-modifying activity is an activity that changes the production rate of equipment such as maintenance and readjustment. If a job is scheduled after the rate-modifying activity, then the processing time varies depending on the modifying rate of the activity. In this study, we extend the single machine problem to parallel machines problem and propose algorithms is to schedule the rate-modifying activities and jobs to minimize the makespan on parallel machines which is NP-hard. We propose a branch and bound algorithm with three lower bounds to solve medium size problems optimally. Also we develop three heuristics, Modified Longest Processing Time, Modified MULTIFIT and Modified COMBINE algorithms to solve large size problems. The test results show that branch and bound algorithm finds the optimal solution in a reasonable time for medium size problems (up to 15 jobs and 5 machines). For large size problem, Modified COMBINE and Modified MULTIFIT algorithms outperform Modified LPT algorithm in terms of solution quality.

• 한국콘텐츠학회:학술대회논문집
• /
• 한국콘텐츠학회 2005년도 춘계 종합학술대회 논문집
• /
• pp.333-336
• /
• 2005

대표적인 개인용 단말기인 휴대폰은 하드웨어의 독립성을 확보할 수 있는 WIPI라는 새로운 플랫폼으로 표준화되고 있어 응용 개발의 가속도를 더하고 있다. 본 논문에서는 이메일과 아바타를 접목시켜 사용자가 이메일을 보내고 받는데 있어서 아바타를 통해 자신을 나타내 보일 수 있도록 WIPI 기반으로 구현하였고, 또한 일반적인 이메일 응용 프로그램들이 이메일과 일정 관리 프로그램을 같이 가지고 있듯이, 본 논문에서도 일정 관리 프로그램을 이메일과 통합하여 쓸 수 있도록 구현하였다. 이 구현 프로그램의 유용성을 더하기 위해, 일정을 통보하기 위한 방법으로 SMS 문자 서비스를 이용하였고, 휴대폰에서 입력한 일정을 PC 기반의 Outlook의 일정과 동기화 할 수 있도록 개발하였다.

• 대한전기학회논문지:전력기술부문A
• /
• 제51권12호
• /
• pp.591-596
• /
• 2002

This Paper Presents a new methodology for Direct Load Control(DLC) and Unit Commitment. To consider economical effect of DLC, we developed 3-Dimensional dynamic programming which can combine unit commitment and DLC. Traditional dynamic programming has 2-Dimensional which consist of state and stage, but newly developed dynamic programming has DLC state, U.C. state, and stage. As a result, economical DLC and unit commitment schedule of the power system is possible. This method is applied to the test system, and the usefulness of the method is verified.

• 국제학술발표논문집
• /
• The 1th International Conference on Construction Engineering and Project Management
• /
• pp.902-907
• /
• 2005

This study was undertaken to develop a comprehensive scheduling method which applied the core concept(DBR) of TOC to PERT, and to combine Monte Carlo Simulation to revise the uncertainties of activities then to eliminate project duration uncertainty. Most of the project duration overlooks the fact that in spite of minimizing the project duration, the uncertainty of constrained resources still puts the reliability of project duration in jeopardy. For the contractor, however, the most important thing is to comply the project scheduling with the planning to reduce the uncertainty of the project activities, operational interaction and project duration. In order to demonstrate that the model can be used in construction project, the scheduling of a steel-structure project was used as a case study to verify the validity of this model.

• 터널과지하공간
• /
• 제19권4호
• /
• pp.275-286
• /
• 2009

해저터널을 굴착할 때 다양한 지반조건에서 발생하는 기술적인 위험에 대한 원인 규명과 조치를 수립하기 위해서는 예상되는 위험 시나리오를 구성하는 것이 중요하다. 또한, 위험 시나리오를 분류할 때 터널 굴착노선 전반에 걸쳐 발생되는 시나리오와 일부 구간에 국한하여 발생되는 시나리오를 함께 고려함으로써 프로젝트관리 측면에서 체계적이고 조직적인 대응을 할 수 있는 논리적인 틀을 제공할 수 있다. 본 연구에서는 위험 시나리오에 대한 관리기법으로 프로젝트 위험 시나리오와 프로젝트 관리요소를 구성하고 파일럿 프로젝트를 선정하여 프로젝트 일정을 수립하였다. 특히 해저터널에서 예상되는 위험 시나리오를 일반 위험 시나리오와 특정 위험 시나리오로 분류하고 프로젝트 관리요소와 연계할 수 있는 개념을 도출하였다.