• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.14 no.4
• /
• pp.1579-1602
• /
• 2020

In the design of production system, buffer capacity allocation is a major step. Through polymorphism analysis of production capacity and production capability, this paper investigates a buffer allocation optimization problem aiming at the multi-stage production line including unreliable machines, which is concerned with maximizing the system theoretical production rate and minimizing the system state entropy for a certain amount of buffers simultaneously. Stochastic process analysis is employed to establish Markov models for repairable modular machines. Considering the complex structure, an improved vector UGF (Universal Generating Function) technique and composition operators are introduced to construct the system model. Then the measures to assess the system's multi-state reliability and structural complexity are given. Based on system theoretical production rate and system state entropy, mathematical model for buffer capacity optimization is built and optimized by a specific genetic algorithm. The feasibility and effectiveness of the proposed method is verified by an application of an engine head production line.

• Journal of Korean Society of Water and Wastewater
• /
• v.21 no.2
• /
• pp.215-224
• /
• 2007

The purpose of this study was to estimates water supply reliability indices of the water supply by Allocation Rules(AR) for parallel reservoirs. Rule (A) can be considered it as only current storage, Rule(B) can be considered it as current storage and inflow and Rule(C) can be considered it as current storage, inflow and water supply capacity. First, conditions of water supply are divided by Condition I for the monthly constant water supply and Condition II for the monthly varied water supply. Second, results of allocation coefficients are revealed the smallest different at Rule(C). The analysis of water supply showed that the capability of water supply is superior to the Rule(B), it is superior to the Rule(C) on the base of the balance of water supply. The reliability analysis was highly showed at the Rule(B) and Rule(C). A methodology for the analysis of water supply was developed and applied to the parallel reservoir system from this research, The operation rule for the parallel reservoir can be slightly modified and successfully applied to the different kinds of the parallel reservoir system.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.1
• /
• pp.204-226
• /
• 2018

Big data processing applications have been migrated into cloud gradually, due to the advantages of cloud computing. Hadoop Distributed File System (HDFS) is one of the fundamental support systems for big data processing on MapReduce-like frameworks, such as Hadoop and Spark. Since HDFS is not aware of the co-location of virtual machines in the cloud, the default scheme of block allocation in HDFS does not fit well in the cloud environments behaving in two aspects: data reliability loss and performance degradation. In this paper, we present a novel location-aware data block allocation strategy (LDBAS). LDBAS jointly optimizes data reliability and performance for upper-layer applications by allocating data blocks according to the locations and different processing capacities of virtual nodes in the cloud. We apply LDBAS to two stages of data allocation of HDFS in the cloud (the initial data allocation and data recovery), and design the corresponding algorithms. Finally, we implement LDBAS into an actual Hadoop cluster and evaluate the performance with the benchmark suite BigDataBench. The experimental results show that LDBAS can guarantee the designed data reliability while reducing the job execution time of the I/O-intensive applications in Hadoop by 8.9% on average and up to 11.2% compared with the original Hadoop in the cloud.

• Journal of the military operations research society of Korea
• /
• v.30 no.1
• /
• pp.48-69
• /
• 2004

An optimal allocation model for SAM-X by using a set covering model is suggested. This allocation model considers to guarantee the maximum security of vital areas from the attack of enemy aircraft(s) and missiles. In order to formulate this model, we applied the concept of parallel structure reliability to set covering model. This model gives both direction of the primary target line and location of the facility. When applied this model to the real situation, the solution of this model can be used to the references of decision making for the optimal military facility allocation.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.4
• /
• pp.334-340
• /
• 2017

Reliability is considered a particularly important design factor for systems that have critical results once a failure occurs in a system, such as trains, airplanes, and passenger ships. The reliability of the system can be improved in several ways, but in a system that requires considerable reliability, the redundancy of parts is efficient in improving the system reliability. In the case of duplicating parts to improve reliability, the kind of parts and the number of duplicating parts should be determined under the system reliability, part costs, and resources. This study examined the redundancy allocation of multi-level systems with serial structures. This paper describes the definition of a multi-system and how to optimize the kind of parts and number of duplications to maximize the system reliability. To optimize the redundancy, the cuckoo search algorithm was applied. The search procedure, the solution representation and the development of the neighborhood solution were proposed to optimize the redundancy allocation of a multi-level system. The results of numerical experiments were compared with the genetic algorithm and cuckoo search algorithm.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.9 no.14
• /
• pp.45-48
• /
• 1986

This paper studies reliability growth model in redundancy allocation of Parallel-series system in which several series system is linked parallelly, The model is generalized by system redundancy of sub-system that have components redundancy. The stage of components in each sub-system is established differently. At the same time by assigned the different number of constraints to the sub-system, this paper deals with rather practical reliability growth model.

• Proceedings of the KIEE Conference
• /
• 2000.07a
• /
• pp.394-396
• /
• 2000

This paper presents a new algorithm for the allocation of the reliability level of composite power system under deregulated electricity market. Under deregulated electricity market, it is required to establish a methodology that can evaluate supply cost and supply reliability of each demand to realize the available priority service reflected a preference of each customer. In this study, a concept of reliability differentiated electricity service as priority service to keep reliability of particular customer within a desirable level is proposed on HLII under deregulated competitive electricity market. The uncertainties of not only generators but also transmission lines are considered for the reliability evaluation in this study. The characteristics and effectiveness of this methodology are illustrated by the case studies on MRBTS and IEEE-RTS.

• Proceedings of the KIEE Conference
• /
• 2003.11a
• /
• pp.151-153
• /
• 2003

This paper proposes determining a optimal number, size and allocation of DGs(Distributed Generations) needed to minimize operation cost of distribution system, obtains economic benefit in operation planning of DG and improves system reliability. System reliability is assessed whether DG install and reliability cost consider. DG optimal allocations are determined to minimize total cost with power buying cost, operation cost of DG, loss cost and outage cost using GA(Genetic Algorithm). And it was determined installed load-point and order.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.53 no.9
• /
• pp.481-486
• /
• 2004

In operation of distribution system, $DG_s$ Distributed Generations) are installed as an alternative of extension and establishment of substations and transmission and distribution lines according to increasing power demand. In operation planning of $DG_s$, determining optimal capacity and allocation gets economical pro(it and improves power reliability. This paper proposes determining a optimal number, size and allocation of $DG_s$ needed to minimize operation cost of distribution system. Capacity of $DG_s$ (or economical operation of distribution system estimated by the load growth and line capacity during operation planning duration, DG allocations are determined to minimize total cost with power buying cost. operation cost of DG, loss cost and outage cost using GA(Genetic Algorithm).

• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.360-362
• /
• 2003

In operation of distribution system, DGs(Distributed Generations) are installed as an alternative of extension and establishment of substations, transmission and distribution lines according to increasing power demand. Optimal capacity and allocation of DGs improve power quality and reliability. This paper proposes a method for determining the optimal number, size and allocation of DGs needed to minimize operation cost of distribution system. Capacity of DGs for economic operation of distribution system can be estimated by the load growth and line capacity during operation planning duration. DG allocations are determined to minimize total cost with failure rate and annual reliability cost of each load point using GA(Genetic Algorithm).