International Journal of Industrial Engineering: Theory, Applications and Practice
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A Multi-objective scheduling of hybrid manufacturing systems with walking workers
No full textHybrid manufacturing systems (HMSs) are the combination of cells and the functional area. It is more suitable in terms of real-world applications to include workers in the product scheduling problem in these systems by the nature of the cells. The multi-objective product scheduling problem in HMS is addressed together with the worker objectives in this study. Three different objectives are identified for the problem: One of them is the minimization of average flow time, and the other two are the minimization of maximum number of workers and the minimization of maximum number of workers changing. Including the number of workers in the objectives presents a realistic approach as well as bringing problem's novelty out. A new detailed mathematical model which reflects real-world applications is developed for the multi-objective product scheduling problem. NSGA-II which is a metaheuristic algorithm and a local search also developed for the study are combined and utilized together. The algorithm proposed through six different hypothetical cases and the original NSGA-II algorithm are compared, and the efficiency of the proposed algorithm is mentioned in the conclusion
EVALUATION OF SYSTEM RELIABILITY FOR A FREEWAY SYSTEM WITH STOCHASTIC SPEED
No full textThe purpose of this study is to apply network analysis 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. From the quality management viewpoint, this can serve as an important performance indictor in the planning and management of freeway system traffic flow. 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
ON THE ROLE OF UNBIASED INVERSE VARIANCE-STABILIZING TRANSFORMATION IN WAVELET SHRINKAGE ESTIMATION FOR NHPP-BASED SOFTWARE RELIABILITY ASSESSMENT
No full textIn non-homogeneous Poisson process (NHPP) based software reliability models (SRM), specifying the software intensity function or the mean value function accurately is important. A wavelet shrinkage estimation (WSE) method has been proposed for estimating NHPP-based SRMs in a non-parametric way. We concentrate on the inverse variance-stabilizing transformation (IVST) used in the last step of WSE and apply unbiased IVST instead of the commonly-used direct algebraic IVST to reduce the bias of the WSE estimator. Through numerical studies with real software fault count data, we show the effectiveness of the WSE combined with unbiased IVST
MASS-CUSTOMIZED OUTPATIENT APPOINTMENT RULE GENERATOR
No full textThis study claims that if a mass-customized appointment rule is developed for each individual outpatient doctor, it could improve the performance and service quality of outpatient clinics. A simulation-based optimization algorithm is proposed for mass-customized appointment rule generation. Various environmental factors, such as preferred appointment intervals, new and return patients, no-shows, walk-in patients, stochastic consultation times, and patient unpunctuality, are considered to generate implementable and practical rules. The simulation-based optimization algorithm uses several well-known appointment rules as initial solutions, evaluates the effectiveness of rules by simulation that considers practical environmental factors, improves rules using a neighborhood search, and reports the best rule. The algorithm generates a variable-block-size/fixed-interval rule consisting of the numbers of new and return patients in each appointment interval. Computational experiments show that the proposed algorithm can generate effective appointment rules with user-provided preferred appointment interval considering the various environmental factors
A DATA-DRIVEN APPROACH TO DESIGNING NEW SERVICES FOR VEHICLE OPERATIONS MANAGEMENT
No full textVarious types and massive amounts of data are collected in the automotive industry. Such data proliferation facilitates and improves the design of services for vehicle operations management (VOM). A VOM service is a service that helps drivers drive safely, conveniently, and pleasurably with the use of VOM-related data. Despite the applicability of big data to VOM service design, few efforts have been made to establish a big data-based design process for VOM services. To fill the research gap, this study proposes an approach to analyzing and utilizing VOM-related data for designing VOM services. The proposed approach aids service designers in designing VOM services by using VOM-related data. A case study on the design of an eco-driving service, a popular VOM service, is presented to demonstrate the feasibility and effectiveness of the approach. The proposed approach could facilitate the design of VOM services and provide a foundation for data-driven service innovations
A SCOR-BASED ANALYTICAL COORDINATION MODEL FOR AN INTEGRATED SUPPLY CHAIN
No full textAn analytical coordination model (ACM) for a multinational corporation (MNC) supply chain is presented in this paper. To improve the supply chain performance, we study the coordination of supply chain parties from the strategic to operational levels. The Supply Chain Operations Reference (SCOR) model is adopted to support the MNC to choose and refine the supply chain management strategies. An optimal integer-ratio inventory coordination (IIC) policy is devised to coordinate the inventory replenishment at the tactical and operational levels. By combining the SCOR model and IIC policy, a systematic approach is proposed. We focus on the derivation and analysis of the total operational cost (TOC) of the supply chain based on cost performance metrics across three levels of the SCOR model version 10. TOC is proven to reach its global minimum after the integer constraint is relaxed. The findings reinforce the proposition that the adoption of an ACM based on the metrics of the SCOR model is promising to assist decision makers in improving the supply chain performance. Numerical experiments are conducted to show how to compute the optimal TOC in practice. The computational results show that the TOC savings through the SCOR-based ACM are significant
COMMON DUE-DATE ASSIGNMENT AND SCHEDULING ON A SINGLE MACHINE WITH SEQUENCE-DEPENDENT SETUPS AND DISCRETELY CONTROLLABLE PROCESSING TIMES
No full textThis study addresses a common due-date assignment and scheduling problem on a single machine in which job processing times are not given, but controllable. The problem is to determine the common due-date, the processing times and the sequence of the jobs to be processed on the single machine. The controllable processing times are considered in the discrete form in that the processing time of a job is determined by selecting one of its discretely available ones with different processing costs. In particular, sequence-dependent setups, in which setup times depend on the type of job just completed and the job to be processed, are also considered. A mixed integer programming model is proposed for the problem that minimizes the sum of earliness, tardiness, due-date assignment and job processing costs. Then, due to the problem complexity, two-stage heuristic algorithms are proposed in which an initial solution is obtained by the positional weights and it is improved by the pairwise interchange method together with determining the job processing times. Computational experiments were done on a number of random instances and the results are reported
Integer Programming versus Constraint Programming: A Course Timetabling Case Study
No full textIn this article, two solution approaches are compared for a real-world, moderate-size but a highly constrained university course timetabling problem. The first approach is developing an integer programming model, and solving it by using a commercial solver. The model proposes new formulations for the constraints that are hard to formulate. The second approach is developing a constraint programming heuristic, and implementing it by a programming language and solving the problem by this heuristic. The heuristic employs a backtracking mechanism inspired from tabu search which was found to be very helpful in identifying the inconsistencies in the input data. Indeed, it was initially developed to identify the courses that prevent feasible timetables from being produced. In order to be able to show the performance of this heuristic, we tested it on different instances of a well-known course timetabling problem, ITC-2007 datasets. A performance comparison of the two methods in terms of both solution quality and computational time is presented for the real-world problem. Different constraint configurations of the problem has been created and the two solution methods have also been compared under different constraint configurations. It has been observed that the relative performances of the two methods significantly differ under various constraint configurations
PLATFORM PLANNING FRAMEWORK FOR OPEN SOURCE HARDWARE DEVELOPMENT WITH CASE STUDY OF PROJECT ARA
No full textThis article illustrates how to evaluate platform design for an open source hardware development project. First, we will look at the open source hardware development as a methodology that fulfills demands for mass customization. In the open source hardware development, project owner offers platform sources and individual developers separately develop various functional modules based on the given platform sources. Then customers will choose each module which best meets their needs. Second, the evaluation model for the open source hardware platform will be suggested. For open source hardware development, developers’ participation is one of key factors to successful project management. Developers will consider both estimated development costs and market size to make decision on participation. With all these concerns, we built a platform evaluation model for open source hardware projects in terms of how much it boosts developers' participation
A multi-agent-based approach to dynamic scheduling and control for a flexible assembly line system
No full textThe success of a flexible assembly manufacturing system depends on efficacious production scheduling and control. Current assembly manufacturing scheduling and control algorithms lack the flexibility and reconfiguration abilities to manage disturbances when they occur. Consequently, system performance worsens quickly when the operation of the system is interrupted. The objective of this research was to examine whether the performance of a flexible assembly line system can be enhanced by implementing a radio frequency identification-based multi-agent distributed (RFIDMAD) scheduling and control system. A multi-agent manufacturing scheduling model was developed and implemented in a flexible assembly manufacturing system using a simulation model. Several measures of the performance of the system were considered in the simulation analysis. The simulation results indicate that an RFIDMAD scheduling and control system can increase the uptime productivity and production rate of an assembly manufacturing system