• Journal of Korean Society for Quality Management
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• v.23 no.3
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• pp.156-166
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• 1995

Job shop scheduling problem is a complex system and an NP-hard problem. Thus it is natural to look for heuristic method. We consider the multi-part production scheduling problem for quality level in a job shop scheduling under the existence of alternative routings. The problem is more complex if the processing time is imprecision. It requires suitable method to deal with imprecision. Fuzzy set theory can be useful in modeling and solving scheduling problems with uncertain processing times. Li-Lee fuzzy number comparison method will be used to compare processing times that evaluated under fuzziness. This study presents heuristic method for quality level in bottleneck-based job shop scheduling under fuzzy environment. On the basis of the proposed method, an example is presented.

• The Mathematical Education
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• v.27 no.1
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• pp.15-23
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• 1988

We are at the onset of a major revolution in education, a revolution unparalleled since the invention of the printing press. The computer will be the instrument of this revolution. Computers and computer application are everywhere these days. Everyone can't avoid the influence of the computer in today's world. The computer is no longer a magical, unfamiliar tool that is used only by researchers or scholars or scientists. The computer helps us do our jobs and even routine tasks more effectively and efficiently. More importantly, it gives us power never before available to solve complex problems. Mathematics instruction in secondary schools is frequently perceived to be more a amendable to the use of computers than are other areas of the school curriculum. This is based on the perception of mathematics as a subject with clearly defined objectives and outcomes that can be reliably measured by devices readily at hand or easily constructed by teachers or researchers. Because of this reason, the first large-scale computerized curriculum projects were in mathematics, and the first educational computer games were mathematics games. And now, the entire mathematics curriculum appears to be the first of the traditional school curriculum areas to be undergoing substantial trasformation because of computers. Recently, many research-Institutes of our country are going to study on computers in orders to use it in mathematics education, but the study is still start ing-step. In order to keep abreast of this trend necessity, and to enhance mathematics teaching/learning which is instructed lecture-based teaching/learning at the present time, this study aims to develop/present practical method of computer-using. This is devided into three methods. 1. Programming teaching/learning method This part is presented the following five types which can teach/learn the mathematical concepts and principle through concise program. (Type 1) Complete a program. (Type 2) Know the given program's content and predict the output. (Type 3) Write a program of the given flow-chart and solve the problem. (Type 4) Make an inference from an error message, find errors and correct them. (Type 5) Investigate complex mathematical fact through program and annotate a program. 2. Problem-solving teaching/learning method solving This part is illustrated how a computer can be used as a tool to help students solve realistic mathematical problems while simultaneously reinforcing their understanding of problem-solving processes. Here, four different problems are presented. For each problem, a four-stage problem-solving model of polya is given: Problem statement, Problem analysis, Computer program, and Looking back/Looking ahead. 3. CAI program teaching/learning method This part is developed/presented courseware of sine theorem section (Mathematics I for high school) in order to avail individualized learning or interactive learning with teacher. (Appendix I, II)

• Journal of Educational Research in Mathematics
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• v.14 no.3
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• pp.267-281
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• 2004

Many students feel the word problems are very difficult. This study analyzes the linguistic and cognitive factors that affect word problem solving so that we help students bring through the difficulty. There are a text base, a situation model, and a real world in the linguistic aspects. Students have a difficulty at the transition from text base to situation model(equation), and make lots of errors at the situation model. In the cognitive aspects, I investigated problem solving schemes, strategies, and complexity level. Students are likely to choose strategy by the contents which teacher instructed, but not by low complexity level, and mix up the amount of sugar and sugar water, and concentration. We can recognize how complex the types of word problems are to solve, which strategies students choose largely, and what errors that students make in the problem solving are.

• Journal of Digital Convergence
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• v.19 no.3
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• pp.13-24
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• 2021

This was a one-group pretest-protest pre-experimental study designed to find out the effects of writing programs on college students using flipped learning for training convergence talents with complex problem solving skills. Data were collected from 27 C university students in G-do, from September 1st to October 30th, 2020. Analysis was done using IBM SPSS 25.0 for frequency (percentage), average, standard deviation, and paired t-test. The study showed that self leadership was enhanced by an average of 0.45 points (p<.001), metacognition by 0.87 points (p<.001), goal orientation by 0,77 points (p<.001), and creativity by 0.51 points (p<.001), so was statistically significant. The study demonstrated that writing programs using filpped learning had the effect of improving complex problem solving skills. so the results are expected to be used as basic data for the development of educational programs for traning convergence talents with problem solving skills at university-level. Also, for current college students that can freely access the online environment, development of various e-learning classes that apply flipped learning is needed.

• Journal of the Korean Operations Research and Management Science Society
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• v.10 no.1
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• pp.54-64
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• 1985

This paper deals with analysis on complex and dynamic Primary Health Care (PHC) Systems in rural community to increase understanding of the nature of PHC feedback systems. Because Industrial Dynamics can be very useful for the analysis of such complex and dynamic systems. We used that as a basic tool of Modelling and simulation running. Even If PHC system-models require many assumptions, simulations based on these models can lead decision makers to a better way of problem solving.

• Journal of Information Technology Applications and Management
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• v.21 no.2
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• pp.127-147
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• 2014

A methodology is often used in solving complex problems. As a typical case of complex problem solving, development of information systems mostly requires a use of system development methodology. However, it is not always easy or smooth for organizations to adopt the methodology and to achieve a positive outcome from their application in real project situations. Although there are a few studies to find out success factors in the implementation of the methodology, they did not take into consideration essential characteristics of the methodology. This study aims to analyze the quality of the methodology as a key determinant to influence the performance of the methodology application.

• Advances in aircraft and spacecraft science
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• v.2 no.1
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• pp.57-76
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• 2015

We investigated complex damped modes in beams in the presence of a viscoelastic layer sandwiched between two elastic layers. The problem was solved using two approaches, (1) Rayleigh beam theory and analyzed using the Ritz method, and (2) by using 2D plane stress elasticity based finite-element method. The damping in the layers was modeled using the complex modulus. Simply-supported, cantilever, and viscously supported boundary conditions were considered in this study. Simple trigonometric functions were used as admissible functions in the Ritz method. The key idea behind sandwich structure is to increase damping in a beam as affected by the presence of a highly-damped core layer vibrating mainly in shear. Different assumptions are utilized in the literature, to model shear deformation in the core layer. In this manuscript, we used FEM without any kinematic assumptions for the transverse shear in both the core and elastic layers. Moreover, numerical examples were studied, where the base and constraining layers were also damped. The loss factor was calculated by modal strain energy method, and by solving a complex eigenvalue problem. The efficiency of the modal strain energy method was tested for different loss factors in the core layer. Complex mode shapes of the beam were also examined in the study, and a comparison was made between viscoelastically and viscously damped structures. The numerical results were compared with those available in the literature, and the results were found to be satisfactory.

• Journal of Computing Science and Engineering
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• v.8 no.4
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• pp.199-206
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• 2014

The ant colony optimization (ACO) algorithm is a new heuristic algorithm that offers good robustness and searching ability. With in-depth exploration, the ACO algorithm exhibits slow convergence speed, and yields local optimization solutions. Based on analysis of the ACO algorithm and the genetic algorithm, we propose a novel hybrid genetic ant colony optimization (NHGAO) algorithm that integrates multi-population strategy, collaborative strategy, genetic strategy, and ant colony strategy, to avoid the premature phenomenon, dynamically balance the global search ability and local search ability, and accelerate the convergence speed. We select the traveling salesman problem to demonstrate the validity and feasibility of the NHGAO algorithm for solving complex optimization problems. The simulation experiment results show that the proposed NHGAO algorithm can obtain the global optimal solution, achieve self-adaptive control parameters, and avoid the phenomena of stagnation and prematurity.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.203-210
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• 2002

The great advantages on the Genetic Algorithms(GAs) are ease of implementation, and robustness in solving a wide variety of problems, several GAs based optimization models for solving complex structural problems were proposed. However, there are two major disadvantages in GAs. The first disadvantage, implementation of GAs-based optimization is computationally too expensive for practical use in the field of structural optimization, particularly for large-scale problems. The second problem is too difficult to find proper parameter for particular problem. Therefore, in this paper, a Distributed Hybrid Genetic Algorithms(DHGAs) is developed for structural optimization on a cluster of personal computers. The algorithm is applied to the minimum weight design of steel structures.

• Journal of the Korea Society of Computer and Information
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• v.24 no.9
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• pp.9-20
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• 2019

In this paper, we study the university timetabling problem, which consists of two subproblems, the university course timetabling problem and the examination timetabling problem. Given a set of classrooms, students, teachers, and lectures, the problem is to assign a number of courses (and examinations) to suitable timeslots and classrooms while satisfying the given set of constraints. We discuss the modeling and solution approaches to construct course and examination timetables for one of the largest Korean university. By using binary integer programming formulations, we describe these two complex real-world problems. Then, we propose a solution method, called NOGOOD, to solve the examination timetabling model. The computation results show that NOGOOD finds the optimal examination schedule for the given instance. Although we consider a specific instance of the university timetabling problem, the methods we use can be applicable to modeling and solving other timetabling problems.