• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.100-103
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• 1999

In this paper, a method for the efficient implementation of the PICNET network configurator for a distributed control system(DCS) is proposed. The network configurator is composed of the time parameter estimator and the period scheduler, the file generator. The main role of network configurator estimates time parameter, the pre-run time scheduling of the user input and make the period transmission table for operating the PICNET based distributed control system.

• Journal of the Korea Society for Simulation
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• v.8 no.2
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• pp.87-100
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• 1999

A manufacturing environment without a computerized system causes numerous problems, since many important decisions are made based on the experience of veteran staffs. Especially, when a strategy for the improvement of manufacturing efficiency is considered, it is hard to predict the effect of the strategy. A solution to the problem without large investment of the computerized system is the simulation study. This paper shows the modeling and simulation based on DEVS(Discrete Event System Specification). Two types of models are implemented, one for representing the current production strategy and the other for the new strategy. The new strategy is expressed as priority rules within the model. The process in concern is the metal grating production process in which the size of the group, for applying a specific cutting and scheduling strategies, is one of the important factors in improving the production efficiency. Some reliable criteria for the evaluation related to the production effeciency are established from the simulation study.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.475-477
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• 2004

글로벌 컴퓨팅 시스템 환경에서 자원 제공자에 의해 수행하는 연산 결과에 대한 정확성을 제공하기 위한 결과 검사 기법은 중요한 고려사항이다. 자원 제공자들은 인터넷에 연결되어 인증 없이 자율적으로 연산에 참여할 수 있기 때문에 이들에 의해 수행된 연산 결과에 대한 정확성을 보장해야만 한다. 기존 연구에서 결과에 대한 정확성을 보장하기 위해 다수 투표법과 결점 검사법을 사용하지만 정확성 검사 기법을 위한 스케줄링 기법을 사용하고 있지 않아 높은 연산 지연 시간과 부하가 발생한다. 따라서, 본 논문에서는 결과 검사에 대한 연산 지연 시간과 부하를 줄일 수 있는 신용도 기반 그룹 구성을 통한 스케줄링 기법을 제안한다.

• Journal of Korean Institute of Industrial Engineers
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• v.19 no.4
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• pp.125-135
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• 1993

An Unrelated Parallel Processing with Weighted jobs and Setup times scheduling prolem is studied. We consider a parallel processing in which a group of processors(machines) perform a single operation on jobs of a number of different job types. The processing time of each job depends on both the job and the machine, and each job has a weight. In addition each machine requires significant setup time between processing jobs of different job types. The performance measure is to minimize total weighted flow time in order to meet the job importance and to minimize in-process inventory. We present a 0-1 Mixed Integer Programming model as an optimizing algorithm. We also present a simple heuristic algorithm. Computational results for the optimal and the heuristic algorithm are reported and the results show that the simple heuristic is quite effective and efficient.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.2
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• pp.142-148
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• 2005

This paper proposes a cell age model for Penicillium chrysogenum fed-batch cultivation to supply a qualitative insight into morphology-associated dynamics. The average ages of the segregated cell populations, such as growing cells, non-growing cells and intact productive cells, were estimated by this model. A combined model was obtained by incorporating the aver-age ages of the cell sub-populations into a known but modified segregated kinetic model from literature. For simulations, no additional effort was needed for parameter identification since the cell age model has no internal parameters. Validation of the combined model was per-formed by 20 charges of industrial-scale penicillin cultivation. Meanwhile, only two charge-dependent parameters were required in the combined model among approximately 20 parameters in total. The model is thus easily transformed into an adaptive model for a further application in on-line state variables prediction and optimal scheduling.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.54
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• pp.13-26
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• 2000

Machining route selection to produce parts should be based on shop flow information because of input data at scheduling tasks and is one of the main problem in process planning. This paper addresses the problem of machining route selection in multi-stage process with machine group included a similar function. The model proposed is formulated as 0-1 integer programing considering the relation of parts and machine table size, avaliable time of each machine for planning period, and delivery date. The objective of the model is to minimize the sum of processing, transportation, and setup time for all parts. Genetic algorithm approach is developed to solve this model. The efficiency of the approach is examined in comparison with the method of branch and bound technique for the same problem. Also, this paper is to solve large problem scale and provide it if the multiple machining routes are existed an optimal solution.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.1288-1289
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• 2012

분산 시스템과 관련하여 P2P 기술은 분산 환경에서 자원을 보유한 개인은 효율적으로 다른 사용자들과 자원을 공유하는 측면에서 활용도 높은 분야이다. 그러나 P2P 시스템은 자원 검색, 전송, 재전송 작업이 이뤄질 때마다 네트워크 트래픽이 과다하게 발생되는 단점을 갖고 있다. 이러한 문제를 해결하여 P2P 시스템의 성능 향상을 목표로 하는 연구가 많은 부분 진행되고 있다. 이러한 성능 향상의 다양한 방향성 가운데 사용자 입장에서의 사용성 개선 측면이 최근 중요한 부분으로 대두되고 있는데 본 연구에서는 사용성을 개선하기 위한 P2P 그룹 관리 검색 알고리즘을 제안한다.

• Journal of Internet Computing and Services
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• v.6 no.6
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• pp.127-137
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• 2005

This paper presents implementation of client-based VOD service using multicast delivery, Conventional system provide server-based system in multicast delivery but implemented system provides on-demand client-based multicast system. The Multicast Agent Scheduler aggregates clients' request and it generate multicast group addresses and port numbers according to requested video items and service request time. Then it transmits immediately multicast address to VOD server and client who request service. And then VOD server transmits requested streams with a multicast group address and the client joins the group automatically. The Multicast Agent Scheduler assigns the same multicast group address when other clients request an identical video within the same scheduling duration. The proposed system can reduce load of server and support many clients at the same time and applies it to WMT(window media technology) of Microsoft.

• Journal of KIISE
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• v.44 no.2
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• pp.213-222
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• 2017

The Internet of Things (IoT) technology is rapidly developing in recent years, and is applicable to various fields. A smart factory is one wherein all the components are organically connected to each other via a WSN, using an intelligent operating system and the IoT. A smart factory technology is used for flexible process automation and custom manufacturing, and hence needs adaptive network management for frequent network fluctuations. Moreover, ensuring the timeliness of the data collected through sensor nodes is crucial. In order to ensure network timeliness, the power consumption for information exchange increases. In this paper, we propose an IEEE 802.15.4e DSME-based distributed scheduling algorithm for mobility support, and we evaluate various performance metrics. The proposed algorithm adaptively assigns communication slots by analyzing the network traffic of each node, and improves the network reliability and timeliness. The experimental results indicate that the throughput of the DSME MAC protocol is better than the IEEE 802.15.4e TSCH and the legacy slotted CSMA/CA in large networks with more than 30 nodes. Also, the proposed algorithm improves the throughput by 15%, higher than other MACs including the original DSME. Experimentally, we confirm that the algorithm reduces power consumption by improving the availability of communication slots. The proposed algorithm improves the power consumption by 40%, higher than other MACs.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.8
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• pp.432-444
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• 2004

In this paper, we construct the TMO-based object group model on distributed environment, and analyze and evaluate the executability for distributed real-time service of our object group model by developing the distributed real-time application simulator applying the model. The Time-triggered Message-triggered Object(TMO) is a real-time server object having real-time property itself. The TMO-based object group is defined as a set of objects which logically reconfigured the physically distributed one or more TMOs on network by a given distributed application. For supporting group management of the server objects, the TMO-based object group we suggested provides the functions which register and withdraw the solver objects as a group member to an arbitrary object group, and also provides the functions which insert and delete the access rights of server objects from clients. Also, our model was designed and implemented to support the appropriate object selection and dynamic binding service for a single TMO as well as the duplicated TMOs, and to support the real-time scheduling service for the clients which are requesting the service. Finally, we developed the Defence System against Invading Enemy Planes(DSIEP) simulator as a practical example of distributed real-time application by applying our model, and evaluated the adaptability of distributed service strategies for the group components and the executability of real-time services that the TMO-based object group model provides.