• Journal of Korean Society of Industrial and Systems Engineering
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• v.14 no.24
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• pp.111-121
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• 1991

This paper considers a non preemtive single processor scheduling problem in which each set have the two common due dates. The objective of the problem is to minimize the weighted mean absolute deviation of job completion times about such two common due dates under the assumption that each job has a different weight. Such a job sequence is an W-shaped sequence. We propose three heuristic solution methods based on several dominance conditions. Numerical examples are presented. The performance comparison is made among three heuristic scheduling procedures.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.60
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• pp.67-72
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• 2000

In this paper we consider to parallel machines scheduling problems for minimizing mean tardiness that is known NP-complete. This problems is classified into two cases, one of which is the case which processing time are identical and the other, nonidentical. A Tabu Search method is applied to the problems considered in this paper to get an improved solution. To this end, we design move attribute, Tabu attribute and Tabu tenure, and thereafter perform the experiments to the problems.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.14 no.23
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• pp.27-36
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• 1991

This paper considers scheduling a set of n-jobs on m-paraller identical processors in which all jobs have the common due date. The objective of the problem is to minimize the weighted mean absolute deviation of job completion times about such common due dates under the assumption that each job has a different weight. and to determine the optimal value of a common due date. We propose four heuristic solution methods based on several dominance conditions, and its solution procedure is illustrated with numerical examples. The Performance comparison is made among four heuristic scheduling procedures.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.1
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• pp.25-32
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• 2019

K-BEMS System was introduced to reduce peak load and to save total energy of the 200 buildings that KEPCO headquarter and branch offices use. And K-BEMS system is composed of PV, battery, and hybrid PCS. KEPCO research institute has carried out this K-BEMS research project for 3 years since January 2016. In this paper, the results of the project are shown. 9 modes of test results of K-BEMS system and are operational problems were analyzed. And measures to cure the trouble are also suggested. Batteries are operated more than 20% of SOC, and less than 20% of SOC battery protection switches are automatically shutting down the system and the system no longer respond to EMS, ending the supply of PV, and so therefore to continue the PV power supply it was turn out to be necessary that the EMS should automatically change its policy to change PV only supply mode automatically when the Battery Switch automatically operated. To operate the system continuously and automatically, it is necessary to modify the minimum operational SOC value, and in addition to that the EMS computer must remember the last shut-down SOC and Voltage which interrupted the system and add some margin to reflect the measurement error in the system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7B
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• pp.427-432
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• 2005

Emerging high broad band multimedia service with high quality has led to demand for challenge of optical access network and Passive Optical Network is one of the most important technologies for future optical access network. In this paper, we study the scheduling algorithm for WDM-PON in SUCCESS network architecture, a next generation hybrid WDM/TDM optical access network architecture. Due to economic implementation of this architecture, the shared resources efficiently need to be assigned and then we propose the efficient scheduling algorithm based on specific architecture and characters of SUCCESS. We evaluate and analyze the performance in terms of the average packet delay and throughput of the whole system.

• Convergence Security Journal
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• v.4 no.3
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• pp.57-82
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• 2004

The confluence of computers, communications, and databases is quickly creating a distributed database where many applications require real-time access to temporally consistent sensor data. We have developed an object-oriented real-time database system called BeeHive to provide a significant improvement in performance and functionality over conventional non-real-time database and object management systems. In this paper, the performance of two data-deadline cognizant scheduling policies EDDF and EDF-DC and the baseline EDF policy with/without admission control are evaluated through extensive experiments on BeeHive. The ranges where data-deadline cognizant scheduling policies are effective and where admission control plays a role are identified.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.12
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• pp.539-546
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• 2002

In this paper, we consider a wireless multimedia environment to service both real-time video traffic and non-real-time WWW-application traffic In our suggested new packet scheduling algorithm, we consider both the accumulation counter and SIR to reduce delay in real-time traffic. In addition, our packet scheduling algorithm gives priority first to real-time video traffic service and then to non-real-time internet Packet service when real-time traffic service is absent. From the simulation results, we find that the AC (Accumulation Counter) scheme has much smaller delay than the conversional M-LWDF scheme for real-time video data users, which has a special quality sensitive to its own delay. We also consider the transmission structure of using both the frame period in the time-axis and the OVSF codes in the code-axis at the same time, which is similar to the structure of HSDPA system.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.215-217
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• 2004

In wireless sensor networks, fair allocation of bandwidth among different nodes is one of the critical problems that effects the serviceability of the entire system. Fair bandwidth allocation mechanisms, like fair queuing, usually need to maintain state, manage buffers, and perform packet scheduling on a per flow basis, and this complexity may prevent them from being cost-effectively implemented and widely deployed. It is a very important and difficult technical issue to provide packet scheduling architecture for fairness in wireless sensor networks. In this paper, we propose an packet scheduling architecture for sensor node, called FISN (Fairness Improvement Sensor Network), that significantly reduces this implementation complexity yet still achieves approximately fair bandwidth allocations. Sensor node for sensing estimate the incoming rate of each sensor device and insert a label into each transmission packet header based on this estimate. Sensor node for forwarding maintain no per flow state; they use FIFO packet scheduling augmented by a probabilistic dropping algorithm that uses the packet labels and an estimate of the aggregate traffic at the gathering node. We present the detailed design, implementation, and evaluation of FISN using simulation. We discuss the fairness improvement and practical engineering challenges of implementing FISN in an experimental sensor network test bed based on ns-2.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.8
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• pp.689-696
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• 2014

This paper presents a scheduling problem for a high-density robotic workcell using multi-objective genetic algorithm. We propose a new algorithm based on NSGA-II(Non-dominated Sorting Algorithm-II) which is the most popular algorithm to solve multi-objective optimization problems. To solve the problem efficiently, the proposed algorithm divides the problem into two processes: clustering and scheduling. In clustering process, we focus on multi-robot positions because they are fixed in manufacturing system and have a great effect on task distribution. We test the algorithm by changing multi-robot positions and compare it to previous work. Test results shows that the proposed algorithm is effective under various conditions.

• Journal of Korea Multimedia Society
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• v.5 no.3
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• pp.323-330
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• 2002

Recently, the existing embedded real-time operating systems(RTOSs) are being developed in terms of various modified versions in every application fields. Major characteristics and difference of these OSs lie in their distinct development of mechanisms which can be used in various environment and task-scheduling function which can control time-limited contingencies. In this paper, we design and implement round/robin scheduling algorithm based on time-sharing with equal-priority for multiple tasks which are provided preemptive and priority task allocation function in $\mu{C/OS-II}$ version 2.03. We propose the most important event-ready list structure in $\mu{C/OS-II}$; kernel, and provide the running result for multiple tasks with equal priority for the proposed structure.