• International Journal of Control, Automation, and Systems
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• v.6 no.4
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• pp.596-606
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• 2008

In this paper, we present a co-design methodology of dynamic optimal network-bandwidth allocation (ONBA) and adaptive control for networked control systems (NCSs) to optimize overall control performance and reduce total network-bandwidth usage. The proposed dynamic co-design strategy integrates adaptive feedback control with real-time scheduling. As part of this co-design methodology, a "closed-loop" ONBA algorithm for NCSs with communication constraints is presented. Network-bandwidth is dynamically assigned to each control loop according to the quality of performance (QoP) information of each control loop. As another part of the co-design methodology, a network quality of service (QoS)-adaptive control design approach is also presented. The idea is based on calculating new control values with reference to the network QoS parameters such as time delays and packet losses measured online. Simulation results show that this co-design approach significantly improves overall control performance and utilizes less bandwidth compared to static strategies.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.94-103
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• 2003

In case of environment requiring safety such as human body and requiring flexible shape, a conventional mechanical actuator system does not satisfy requirements. Therefore, in order to solve these problems. a research of various smart material such as EAP (Electro Active Polymer), EAC (Electro Active Ceramic) and SMA (Shape Memory Alloy) is in progress. Recently, the highest preferring material among various smart material is EP (Electrostictive Polymer), because it has very fast response time, powerful force and large displacement. The previous researches have been studied properties of polymer and simple control, but present researches are studied a polymer actuator. An EP (Electostrictive Polymer) actuator has properties which change variably ils shape and environmental condition. Therefore, in order to coincide with a user's purpose, it is important not only to decide a shape of actuator and mechanical design but also to investigate a efficient controller. In this paper, we constructed the control logic with an adaptive fuzzy algorithm which depends on the physical properties of EP that has a dielectric constant depending on time. It caused for a sub-actuator to operate at the same time that a sub-actuator system operation increase with a functional improvement and control efficiency improvement in each actuator, hence it becomes very important to manage it effectively and to control the sub-system which Is operated effectively. There is a limitation on the management of Main-host system which has multiple sub-system, hence it brings out the Multi-Vehicle Control process that disperse the task efficiently. Controlling the multi-dispersion system efficiently, it needs the research of Main-host system's scheduling, data interchange between sub-actuators, data interchange between Main-host system and sub-actuator system, and data communication process. Therefore in this papers, we compared the fuzzy controller with the adaptive fuzzy controller. also, we applied the scheduling method for efficient multi-control in EP Actuator and the algorithm with interchanging data, protocol design.

• Journal of Internet Computing and Services
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• v.5 no.6
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• pp.11-20
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• 2004

Proportional Fair (PF) share policy has been adopted as a downlink scheduling scheme in CDMA2000 l×EV-DO standard. Although It offers optimal performance in aggregate throughput conditioned on equal time share among users, it cannot provide a bandwidth guarantee and a strict delay bound. which is essential requirements of real-time (RT) applications. In this study, we propose a new scheduling policy that provides quality-of-service (QoS) guarantees to a variety of traffic types demanding diverse service requirements. In our policy data traffic is categorized Into three classes, depending on sensitivity of Its performance to delay or throughput. And the primary components of our policy, namely, Proportional Fair (PF), Weighted Fair Queuing (WFQ), and delay-based prioritized scheme are intelligently combined to satisfy QoS requirements of each traffic type. In our policy all the traffic categories run on the PF policy as a basis. However the level of emphasis on each of those ingredient policies is changed in an adaptive manner by taking into account the channel conditions and QoS requirements. Such flexibility of our proposed policy leads to offering QoS guarantees effectively and. at the same time, maximizing the throughput. Simulations are used to verify the performance of the proposed scheduling policy. Experimental results show that our proposal can provide guaranteed throughput and maximum delay bound more efficiently compared to other policies.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.95-97
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• 1998

본 논문에서는 멀티미디어 프로세서의 특성을 반영한 프로세서 스케줄러를 설계하고 실제 구현을 통해 성능을 분석하였다. 제안한 프로세서 스케줄링 기법은 주기가 짧은 프로세서에 높은 우선순위를 부여하지만 우선 순위를 결정하기 위한 주기를 이전 작업의 주기에 위해 동적으로 계산하고 프로세서의 수행 중의 중단을 제한함으로써 Rate Monotonic 알고리즘을 동적이고 비중단적으로 수정하였다. 제안한 스케줄링 기법은 BSD를 기초로 한 운영체제인 FreeBSD 상에서 구현하여 스케줄링의 성능을 평가하였다. 제안한 스케줄러에 대한 실험에서 FreeBSD 스케줄러에 비해 멀티미디어의 실시간적인 특성을 만족하면서 수행 중의 동적인 상황 변화에 적응된 결과를 보인다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.1
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• pp.287-307
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• 2018

There are two targets to schedule parallel jobs in the Cloud: (1) scheduling the jobs as many as possible, and (2) reducing the average execution time of the jobs. Most of previous work mainly focuses on the computing speed of resources without considering other attributes, such as bandwidth, memory and so on. Especially, past work does not consider the supply-demand condition from those attributes. Resources have different attributes, considering those attributes together makes the scheduling problem more difficult. This is the problem that we try to solve in this paper. First of all, we propose a new parallel job scheduling method based on a classification method of resources from different attributes, and then a scheduling method-CPLMT (Cloud parallel scheduling based on the lists of multiple attributes) is proposed for the parallel tasks. The classification method categories resources into different kinds according to the number of resources that satisfy the job from different attributes of the resource, such as the speed of the resource, memory and so on. Different kinds have different priorities in the scheduling. For the job that belongs to the same kinds, we propose CPLMT to schedule those jobs. Comparisons between our method, FIFO (First in first out), ASJS (Adaptive Scoring Job Scheduling), Fair and CMMS (Cloud-Minmin) are executed under different environments. The simulation results show that our proposed CPLMT not only reduces the number of unfinished jobs, but also reduces the average execution time.

• Journal of the Korean Operations Research and Management Science Society
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• v.30 no.2
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• pp.29-40
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• 2005

In this research, we propose packet scheduling algorithm considering different QoS characteristics of real-time traffic and non-real-time traffic in the next generation wireless communication system serving the multimedia traffic and a new efficient framing method cooperated with this packet scheduler. When the selected traffic classes of the selected users are transmitted, our proposed framing method can increase the number of serviced traffic classes by mixing the many different traffic classes within one frame considering data rate decided by the allocated AMC (Adaptive Modulation and Coding) option. Using this proposed method, the fairness among the traffic classes can be achieved and the system performance for total throughput and delay can be enhanced. Simulations are performed to analyze the performance of the proposed framing method. Our proposed packet scheduler and framing method will be applied to the next generation multimedia wireless communication system serving many traffic classes.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.261-266
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• 2007

UMTS release 5 에서 소개된 HSDPA 를 위해 도입된 새로운 기술 Adaptive Modulation and Coding, Hybrid Automatic Repeal reQuest, Fast Packet Scheduling 에 대해 알아보고 여기서 key role 이 되는 Fast Packet Scheduling 알고리즘 가운데 대표적인 세 가지 Round Robin(RR), Promotional Fairness(PF), Maximum Channel Quality Index(Max CQI) 알고리즘의 성능을 시스템 수율과 공평성의 관점에서 분석해보았다. 시스템 수율에서는 Max CQI, PF. RR 알고리즘 순이었으며 공평성 측면에서는 RR, PF Max CQI 알고리즘 순으로 나타났다. 같은 시스템, 같은 망 구조 내에서라면 알고리즘을 최적화하여 QoS와 성능을 극대화할 수 있도록 지속적인 연구가 필요하다.

• Transactions on Control, Automation and Systems Engineering
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• v.3 no.2
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• pp.106-110
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• 2001

The external force disturbance is the one of the main causes that deteriorate the performance of the magnetic suspension. Thus, this paper develops a fuzzy estimator for gain scheduling control of magnetic suspension system suffering from the unknown disturbance. The propose fuzzy estimator computes the disturbance injected to the plant the gain scheduled controller generates the corresponding stabilizing control input associated with estimated disturbance. In the simulation results we confirm the novelty of the proposed control scheme comparing with the other method using a feedback linearization.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.345-348
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• 2004

Every bridge node participating in multiple piconets and forming a scatternet should schedule the inter-piconet traffics in an efficient manner. Frequent piconet switching due to short polling intervals for the links of a bridge node leads to considerable time slots loss caused by the guard time and power consumption for transceiving and processing. On the other hand, restrained piconet switching may result in failures of fulfilling QoS (Quality of Service) requirements for some links. Tn this paper, we present a QoS aware inter-piconet scheduling scheme minimizing the piconet switching events within guaranteed QoS requirements. According to simulation results, the proposed scheme is confirmed to have great improvement in throughput and number of switching events over the credit scheme as current inter-piconet scheduling scheme for the scatter mode.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.322-325
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• 2000

In a batch scheduling policy being different from real video system, the requests are not served immediately due to grouping user's requests upon every scheduling points. Such waiting delays by inefficient managements makes an unfair service to users and increases the possibility of higher reneging rates. This paper proposes an adaptive batch scheduling scheme which reduces the average waiting time of user’s requests and reduces the starvation problem for requesters of less popular movies. The proposed scheme selects dynamically multiple videos in given intervals based on the service patterns which reflect the popularity distribution and resource utilizations. Experimental simulation shows that proposed scheme improves about 20-30 percent of average waiting time and reduces significantly the starving requesters comparing with those of conventional methods such as FCFS and MQL.