Browsing by Author "Lin, Yi-Kuei"

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A Binding Algorithm of Lower Boundary Points Generation for Network Reliability Evaluation
(2020-09-01)
Huang, Ding-Hsiang
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Huang, Cheng-Fu
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Lin, Yi-Kuei
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工業工程與管理學系
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Department of Industrial Engineering and Management
Network reliability evaluation for a stochastic flow network (SFN) can be computed in terms of all lower boundary points (LBPs). Although several algorithms have been presented in the literature as solutions for the LBP problem, the efficiency is always occurring at the present for the large SFN. In this paper, a binding technique generating binding-flow vectors is therefore developed to narrow down the searching range of flows for demand. This technique is able to reduce the loading of the candidate comparison procedure greatly. An algorithm based on this binding technique is proposed to solve the LBP problem. We compare the performance of the proposed algorithm to well-known algorithms in terms of CPU time, through three benchmark networks and a practical case. The experimental results show the functional efficiency of our proposed binding LBP algorithm.
A novel minimal cut-based algorithm to find all minimal capacity vectors for multi-state flow networks
(2020-05-01)
Huang, Ding-Hsiang
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Huang, Cheng-Fu
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Lin, Yi-Kuei
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工業工程與管理學系
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Department of Industrial Engineering and Management
y Real systems, such as computer systems, can be modeled as network topologies with vertices and edges. Owing to equipment failures and maintenance requirements, the capacities of edges have several states. Such systems are regarded as multi-state flow networks (MSFN). System reliability of an MSFN is the probability that the required flow (i.e., demand) can successfully be sent from the source to the sink. By adopting a minimal path (MP) approach, system reliability can be computed in terms of all minimal capacity vectors meeting the demand d. A minimal capacity vector is called a d-MP. Although several algorithms have been presented in the literature for finding all d-MP, improving efficiency in the search for all d-MP is always a challenge. A group approach with both the concepts of minimal cut and MP is developed in this study, narrowing the search range of feasible flow vectors. An algorithm based on the group approach is then proposed to improve the efficiency of the d-MP search. According to the structure of the proposed algorithm, parallel computing can be implemented with significant improvement in the efficiency of the d-MP generation, where the proposed algorithm is compared with previous ones based on three benchmarks, in terms of CPU time. (C) 2019 Elsevier B.V. All rights reserved.
A permutation-and-backtrack approach for reliability evaluation in multistate information networks
(2020-05-15)
Chen, Shin-Guang
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Lin, Yi-Kuei
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工業工程與管理學系
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Department of Industrial Engineering and Management
Nowadays, people live heavily on information systems to handle their business and schedules. A reliable information system helps people smoothly and efficiently deal with their daily-life affairs. An information system usually consists of connected software and hardware components, and can be modeled by connected graphs. In network theory, such graphs are called multistate information networks. Therefore, the reliability of an information system can be evaluated by network theory, namely network reliability. The most popular approach to evaluate network reliability is the three-stage-approach (TSA), which involves (a) finding all minimal paths (MPs), (b) finding all d-system vectors (d-SVs), and (c) calculating the union probability of d-SVs for reliability. Approaches for creating all MPs has been reported. There is a need for a more efficient approach to generate all d-SVs for such calculation. In this article, an approach based on permutation-and-backtrack facility is proposed to generate all such d-SVs. The efficiency of this approach is generally accepted to be superior to the existing approaches. The proposed approach provides us an efficient, and simple way to speed up TSA as a more powerful tool for evaluating the reliability of multistate information networks. (C) 2020 Elsevier Inc. All rights reserved.
Bi-objective optimization for a multistate job-shop production network using NSGA-II and TOPSIS
(2019-07-01)
Lin, Yi-Kuei
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Chang, Ping-Chen
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Yeng, Louis Cheng-Lu
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Huan, Shang-Fu
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工業工程與管理學系
A job-shop production system (JPS) is a manufacturing system wherein each workstation configures multiple types of machines to produce small batches of a variety of products. In each workstation of a JPS, the number of machines that operate normally exhibits multiple levels of capacity owing to failures, partial failures, and maintenance. That is, the number of normal machines in each workstation is stochastic (i.e., multistate). To analyze such a JPS, the JPS is transformed into a multistate job-shop production network (MJPN) using a network topology. For the MJPN, a critical issue is to maximize the network reliability and to minimize the purchase cost when setting up the JPS. To achieve such bi-objective optimization, a machine vector (MV) representing the current number of normal machines in each workstation is introduced to evaluate network reliability. An algorithm based on a depth-first search (DFS) with an expanding technique is proposed to search all MVs for satisfying demand. Subsequently, to obtain a machine configuration (MF) simultaneously having the maximal network reliability and the minimal purchase cost, a two-stage approach is developed based on the non-dominated sorting genetic algorithm II (NSGA-II) and the technique for order of preference by similarity to ideal solution (TOPSIS). A real case of t-shirt production is utilized to illustrate the proposed method.
EVALUATION OF SYSTEM RELIABILITY FOR A FREEWAY SYSTEM WITH STOCHASTIC SPEED
(2019-01-01)
Lin, Yi-Kuei
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Huang, Cheng-Fu
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Lin, Jsen-Shung
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Li, Shin-Ying
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工業工程與管理學系
The purpose of this study is to evaluate the service performance of a freeway system, in which the speed on each section is stochastic owing to user behavior, accidents, tunnels, road gradient, and road repairs. A stochastic-flow freeway network (SFFN) is constructed to model the freeway system with stochastic speed. System reliability is defined as the probability of a certain number of vehicles in a freeway system completing their journey smoothly within a restricted time. Two SFFN models were built to describe the relationships among traffic flow, system time and stochastic speed. After obtaining the probability distribution of speed by collecting historical data, two algorithms with respect to different models were proposed to generate all minimal speed vectors (MSVs). The system reliability can be subsequently computed in terms of MSVs. The Taiwan freeway system was considered as a case study to demonstrate the effectiveness of the proposed models and algorithms.
Exact project reliability for a multi-state project network subject to time and budget constraints
(2020-03-01)
Huang, Ding-Hsiang
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Huang, Cheng-Fu
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Lin, Yi-Kuei
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工業工程與管理學系
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Department of Industrial Engineering and Management
In a project, the duration of every activity is uncertain because of weather, availability of machines, human resources, and unexpected situations, and the cost is influenced by the duration. For modeling the uncertain durations, a multi-state project network (MPN) is proposed. To understand the performance of an MPN, project reliability is calculated and defined as the probability that a project can be completed within time and budget constraints. All feasible project state vectors are contained in upper and lower boundary points. The previous literature only calculated an estimated project reliability. To obtain the exact project reliability, a decomposition approach is developed to obtain subsets of feasible project state vectors. Each subset is firstly formed in terms of one upper boundary point and all lower boundary points. Each subset is further simplified to reduce the number of lower boundary points for computational efficiency. An algorithm with the decomposition approach is subsequently proposed to evaluate the exact project reliability. A real project of new manufacturing lines is demonstrated with several combinations of time and budget constraints to show the effectiveness of the proposed algorithm, and project managers can make decisions based on project reliability.
Network reliability evaluation for a distributed network with edge computing
(2020-09-01)
Huang, Cheng-Fu
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Huang, Ding-Hsiang
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Lin, Yi-Kuei
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工業工程與管理學系
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Department of Industrial Engineering and Management
Reliability and speed are crucial for ensuring robustness in a computer network, which is used for sharing information and resources within a business. The two most recent and important developments in the field of computing are cloud computing and edge computing. In this study, a modern distributed network comprising computers, internet of things (IoT), edge servers, and cloud servers for data transmission was investigated. A distributed network can be modeled as a graph with nodes and arcs, in which each arc represents a transmission line, and each node represents an IoT device, an edge server, or a cloud server. The data are transmitted through these transmission lines which are combined with numerous physical lines such as fiber cables. Therefore, each transmission line has several possible capacities and the capacity of each arc in the distributed network can be regarded as a multistate. Such the distributed network is called a multi-state distributed network (MDN). In an MDN, the data produced by IoT devices are transmitted to the edge servers. After being processed and compressed by the edge servers, the data are then transmitted to the cloud servers for advance computing. The purpose of this study is to first construct a model of a network in order to elucidate the flow relationship among the IoT devices, edge servers, and cloud servers and subsequently develop an algorithm to evaluate network reliability, which is the probability of the data being successfully processed by the MDN.
Preface: reliability and quality management in stochastic systems
(2019-06-01)
Lin, Yi-Kuei
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Zuo, Ming J.
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Hoang Pham
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工業工程與管理學系
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Department of Industrial Engineering and Management
This special issue of the Annals of Operations Research is related to the Asia-Pacific International Symposium on Advanced Reliability and Maintenance Modeling (APARM 2016), held during 24-26 August 2016, at the Hanyang University, Seoul, South Korea. It focuses on new international research in theoretical and related applications to solve quality management problems. Reliability and quality management are quite important in many practical stochastic systems, such as computer systems, logistic systems, production systems, and the like. Developing and applying operations research methods to measure the robustness and to solve the engineering problem of a stochastic system is indeed a crucial task, enabling the system manager to carry out improvements after measuring the stochastic system.
Reliability Evaluation for a Stochastic Flow Network Based on Upper and Lower Boundary Vectors
(2019-11-01)
Huang, Ding-Hsiang
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Huang, Cheng-Fu
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Lin, Yi-Kuei
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工業工程與管理學系
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Department of Industrial Engineering and Management
For stochastic flow network (SFN), given all the lower (or upper) boundary points, the classic problem is to calculate the probability that the capacity vectors are greater than or equal to the lower boundary points (less than or equal to the upper boundary points). However, in some practical cases, SFN reliability would be evaluated between the lower and upper boundary points at the same time. The evaluation of SFN reliability with upper and lower boundary points at the same time is the focus of this paper. Because of intricate relationships among upper and lower boundary points, a decomposition approach is developed to obtain several simplified subsets. SFN reliability is calculated according to these subsets by means of the inclusion-exclusion principle. Two heuristic options are then established in order to calculate SFN reliability in an efficient direction based on the lower and upper boundary points.
Reliability evaluation in terms of flow data mining for multistate networks
(1970-01-01)
Lin, Yi-Kuei
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Chen, Shin-Guang
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工業工程與管理學系
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Department of Industrial Engineering and Management
Network reliability is famous for its problem solving ability in several real-life applications. However, due to its NP-hard nature (Ball in IEEE Trans Reliab 35(3):230-238, 1986), researchers are devoted to the improvement of computational efficiency in various approaches. Although flow in networks depicts its combination properties, only few of them are useful in the calculation of network reliability. In some point of views, we call it mining in flow data. This paper presents techniques of how to efficiently do the flow data mining tasks. A skill based on backtrack and maximal flow is illustrated with examples and benchmarks. The results show that the proposed approach is valuable in the calculation of network reliability.
Reliability of time-constrained multi-state network susceptible to correlated component faults
(1970-01-01)
Lin, Yi-Kuei
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Fiondella, Lance
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Chang, Ping-Chen
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工業工程與管理學系
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Department of Industrial Engineering and Management
Correlation can seriously degrade reliability and capacity due to the simultaneous failure of multiple components, which lowers the probability that a system can execute its required functions with acceptable levels of confidence. The high cost of fault in time-critical systems necessitates methods to explicitly consider the influence of correlation on reliability. This paper constructs a network-structured model, namely time-constrained multi-state network (TCMSN), to investigate the capacity of a computer network. In the TCMSN, the physical lines comprising the edges of the computer network experience correlated faults. Our approach quantifies the probability that d units of data can be sent from source to sink in no more than T units of time. This probability that the computer network delivers a specified level of data before the deadline is referred to as the system reliability. Experimental results indicate that the negative influence of correlation on reliability could be significant, especially when the data amount is close to network bandwidth and the time constraint is tight. The modeling approach will subsequently promote design and optimization studies to mitigate the vulnerability of networks to correlated faults.
System reliability estimation and sensitivity analysis for multi-state manufacturing network with joint buffers-A simulation approach
(2019-08-01)
Chang, Ping-Chen
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Lin, Yi-Kuei
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Chiang, Yu-Min
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工業工程與管理學系
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Department of Industrial Engineering and Management
This paper proposes a simulation approach to estimate system reliability of a multi-state manufacturing network (MSMN) with joint buffers. The system reliability is an indicator to evaluate the probability that an MSMN can provide sufficient capacity to meet a given demand. From the perspective of industrial and systems engineering, the MSMN is constructed as a network topology in which each node denotes an inspection point and arcs denote workstations. In particular, joint buffers with finite volume are embedded in such a topology. Based on the topology, workload processed by each workstation is derived according to a given demand. Subsequently, a simulation approach is applied to randomly generate the current capacity state for the MSMN and to compute the buffer usage under such a state. System reliability is estimated after several iterations of simulation to check if the generated capacity state is available to process the workload or not. Besides, sensitivity analysis is adopted to investigate the most potential location to increase buffer volume. Two practical examples are adopted to validate the effectiveness of the proposed simulation approach. Experimental results show that using joint buffers is more reliable than using parallel buffers in separated production lines.