• Title/Summary/Keyword: Sequencing problem

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A SCORM-based e-Learning Process Control Model and Its Modeling System

  • Kim, Hyun-Ah;Lee, Eun-Jung;Chun, Jun-Chul;Kim, Kwang-Hoon Pio
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.5 no.11
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    • pp.2121-2142
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    • 2011
  • In this paper, we propose an e-Learning process control model that aims to graphically describe and automatically generate the manifest of sequencing prerequisites in packaging SCORM's content aggregation models. In specifying the e-Learning activity sequencing, SCORM provides the concept of sequencing prerequisites to be manifested on each e-Learning activity of the corresponding tree-structured content organization model. However, the course developer is required to completely understand the SCORM's complicated sequencing prerequisites and other extensions. So, it is necessary to achieve an efficient way of packaging for the e-Learning content organization models. The e-Learning process control model proposed in this paper ought to be an impeccable solution for this problem. Consequently, this paper aims to realize a new concept of process-driven e-Learning content aggregating approach supporting the e-Learning process control model and to implement its e-Learning process modeling system graphically describing and automatically generating the SCORM's sequencing prerequisites. Eventually, the proposed model becomes a theoretical basis for implementing a SCORM-based e-Learning process management system satisfying the SCORM's sequencing prerequisite specifications. We strongly believe that the e-Learning process control model and its modeling system achieve convenient packaging in SCORM's content organization models and in implementing an e-Learning management system as well.

Minimizing Total Flow Time for Multiple Parts and Assembly Flow Shop (복수의 부품 및 조립 흐름공정의 총흐름시간 최소화)

  • Moon, Gee-Ju;Lee, Jae-Wook
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.34 no.4
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    • pp.82-88
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    • 2011
  • A typical job sequencing problem is studied in this research to improve productivities in manufacturing companies. The problem consists of two-stage parts and assembly processes. Two parts are provided independently each other and then two sequential assembly processes are followed. A new heuristic is developed to solve the new type of sequencing problem. Initial solution is developed in the first stage and then the initial solution is improved in the second stage. In the first stage, a longer part manufacturing time for each job is selected between two, and then a sequence is determined by descending order of the times. This initial sequence is compared with Johnson's sequence obtained from 2-machine assembly times. Any mismatches are tried to switch as one possible alternative and completion time is calculated to determine whether to accept the new sequence or not to replace the current sequence. Searching process stops if no more improvement can be made.

Whole genome sequencing of foot-and-mouth disease virus using benchtop next generation sequencing (NGS) system

  • Moon, Sung-Hyun;Oh, Yeonsu;Tark, Dongseob;Cho, Ho-Seong
    • Korean Journal of Veterinary Service
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    • v.42 no.4
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    • pp.297-300
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    • 2019
  • In countries with FMD vaccination, as in Korea, typical clinical signs do not appear, and even in FMD positive cases, it is difficult to isolate the FMDV or obtain whole genome sequence. To overcome this problem, more rapid and simple NGS system is required to control FMD in Korea. FMDV (O/Boeun/ SKR/2017) RNA was extracted and sequenced using Ion Torrent's bench-top sequencer with amplicon panel with optimized bioinformatics pipelines. The whole genome sequencing of raw data generated data of 1,839,864 (mean read length 283 bp) reads comprising a total of 521,641,058 (≥Q20 475,327,721). Compared with FMDV (GenBank accession No. MG983730), the FMDV sequences in this study showed 99.83% nucleotide identity. Further study is needed to identify these differences. In this study, fast and robust methods for benchtop next generation sequencing (NGS) system was developed for analysis of Foot-and-mouth disease virus (FMDV) whole genome sequences.

정수계획법을 이용한 프로젝트 확장순서결정에 관한 연구

  • Gang Seok-Ho;Kim Ji-Seung
    • Journal of the military operations research society of Korea
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    • v.11 no.2
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    • pp.15-22
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    • 1985
  • Planning for the expansion of production capacity is of vital importance in many applications within the private and public sectors. This paper considers a sequencing expansion problem in which capacity can be added only at discrete points in time. Given the demand forecast of each period, capacity and cost of each expansion project, we are to determine the sequence of expansion necessary to provide sufficient capacity to meet the demand in all periods at minimum cost. This problem is formulated as a pure integer programming and solved by branch and bound method using Lagrangian relaxation. At first, simple sequencing expansion problem is presented, and in the latter part, extension to include precedence between projects is suggested.

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A Genetic Algorithm for Single Machine Scheduling with Unequal Release Dates and Due Dates (상이한 납기와 도착시간을 갖는 단일기계 일정계획을 위한 유전 알고리즘 설계)

  • 이동현;이경근;김재균;박창권;장길상
    • Journal of the Korean Operations Research and Management Science Society
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    • v.24 no.3
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    • pp.73-82
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    • 1999
  • In this paper, we address a single machine non-preemptive n-job scheduling problem to minimize the sum of earliness and tardiness with different release times and due dates. To solve the problem, we propose a genetic algorithm with new crossover and mutation operators to find the job sequencing. For the proposed genetic algorithm, the optimal pair of crossover and mutation rates is investigated. To illustrate the suitability of genetic algorithm, solutions of genetic algorithm are compared with solutions of exhaustive enumeration method in small size problems and tabu search method in large size problems. Computational results demonstrate that the proposed genetic algorithm provides the near-optimal job sequencing in the real world problem.

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Constraint Description language and Automatic Code Generator for Single-Machine Job Sequencing Problems (단일기계 일정계획을 위한 제약조건 표현언어 및 코드 자동생성기)

  • Lee, You-K.;Baek, Seon-D.;Bae, Sung-M.;Jun, Chi-H.;Chang, Soo-Y.;Choi, In-J.
    • Journal of Korean Institute of Industrial Engineers
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    • v.22 no.2
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    • pp.209-229
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    • 1996
  • Scheduling problems which determine the sequence of jobs are one of the Important issues to many industries. This paper deals with a single-machine job sequencing problem which has complex constraints and an objective function. To solve the problem, an expressive constraint description language and an automatic code generator are developed for our scheduling system. The user just needs to describe the scheduling problem using the constraint description language that allows to express both quantitative and qualitative constraints as well as an objective function in real world semantics. Then, a complete scheduling program based on constraint satisfaction technique is automatically generated through the code generator. Advantage of this approach is that models of the scheduling problems are easily developed and maintained because models ore formulated by using the language which reflects real world semantics.

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Job Sequencing Problem for Three-Machine Flow Shop with Fuzzy Processing Times

  • Park, Seunghun;Chang, Inseong;Gen, Mitsuo
    • Journal of the Korean Operations Research and Management Science Society
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    • v.18 no.1
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    • pp.139-157
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    • 1993
  • This paper presents possibilistic job scheduling based on the membership function as an alternative to probabilistic job scheduling and illustrates a methodology for solving job sequencing problem which the opinions of experts greatly disagree in each processing time. Triangular fuzzy numbers are used to represent the processing times of experts. Here, the comparison method is based on the dominance property. The criteria for dominance are presented. By the dominance criteria, for each job, a mojor TFN and a minor TFN are selected and apessimistic sequence with mojor TFNs and an optimistic sequence with minor TFNs are computed. The three-machine flow shop problem is considered as an example to illustrate the approach.

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A Study on the Heuristic Algorithm for n/m Flow- Shop Problem (n/m 흐름작업의 Heuristic 기법에 관한 연구)

  • 이근부
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.5 no.6
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    • pp.41-48
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    • 1982
  • This paper analyzed md developed flow - shop sequencing heuristic method. The essence of the heuristic approach is in the application of selective routine that reduce the size of a problem. The advantages of this approach are consistency. Speed, endurance and the ability to cope with more data and larger systems than is humanly possible, In recent years many heuristic procedures have been suggested for the flow - shop sequencing problem. Although limited comparisons of these procedures have been made, a full scale test and evaluation have not been reported previously. The maximum flow - time criterion is selected as the evaluation criterion is selected as the evaluation criterion of flow - shop's efficiency. The author evaluated these 3 heuristic method's performance. By the evaluation of the result, we can see that the modified methods produce a shorter maximum flow - time than the original methods.

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Efficiently Solving Dispatching Process Problems in Nurseries by Heuristic Techniques

  • Erhan, Kozan
    • Industrial Engineering and Management Systems
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    • v.1 no.1
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    • pp.10-18
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    • 2002
  • A more comprehensive analytical framework for examining the relative merits of alternative dispatching process policies for nurseries is developed in this paper. The efficiency of the dispatch process of plants in a nursery is analysed using a vehicle routing model. The problem then involves determining in what order each vehicle should visit its locations. The problem is NP-hard. Several heuristic techniques are used to solve a real life nursery sequencing problem. The results obtained by these heuristic techniques are compared with each other and the current sequencing of orders. The model with some minor alterations can be also used to minimise the dispatching and collecting process in different agricultural plants.

Heuristics for Sequencing Printed Circuit Boards on a Surface Mount Device Placement Machine (SMD기계의 PCB 생산순서 결정을 위한 발견적 기법)

  • Song, Chang-Yong;Shinn, Seong-Whan
    • IE interfaces
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    • v.13 no.2
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    • pp.195-203
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    • 2000
  • This paper considers the problem of sequencing printed circuit boards(PCBs) on an automatic surface mount device(SMD) placement machine in order to minimize total setup time. Since the total set of component feeders needed by all boards cannot be loaded simultaneously on the magazine, the setup must be made between two successive boards in the sequence. It is assumed that the setup time depends on the number of component feeders to be replaced in the magazine. An important characteristic is that each feeder occupies a different number of slots in the magazine. This problem is equivalent to travelling salesman problem(TSP) except that the distances between two cities, that is, the setup times between two boards, are not known in advance. So, TSP-based heuristics with new distance functions are presented and their performances are compared through various test problems. Computational results indicate that our heuristics outperform existing methods.

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