• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.4
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• pp.98-108
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• 2015

This paper introduces the existence of purchase dependence that was identified during the analysis of inventory operations practice at a sales agency of dealing with spare parts for ship engines and generators. Purchase dependence is an important factor in designing an inventory replenishment policy. However, it has remained mostly unaddressed. Purchase dependence is different from demand dependence. Purchase dependence deals with the purchase behavior of customers, whereas demand dependence deals with the relationship between item-demands. In order to deal with purchase dependence in inventory operations practice, this paper proposes (Q, r) models with the consideration of purchase dependence. Through a computer simulation experiment, this paper compares performance of the proposed (Q, r) models to that of a (Q, r) model ignoring purchase dependence. The simulation experiment is conducted for two cases : a case of using a lost sale cost and a case of using a service level. For a case of using a lost sale cost, this paper calculates an order quantity, Q and a reorder point, r using the iterative procedure. However, for a case of using a service level, it is not an easy task to find Q and r. The complexity stems from the interactions among inventory replenishment policies for items. Thus, this paper considers the genetic algorithm (GA) as an optimization method. The simulation results demonstrates that the proposed (Q, r) models incur less inventory operations cost (satisfies better service levels) than a (Q, r) model ignoring purchase dependence. As a result, the simulation results supports that it is important to consider purchase dependence in the inventory operations practice.

• Journal of Korean society of Dental Hygiene
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• v.12 no.1
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• pp.93-101
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• 2012

Objectives : The purpose of this study was to examine the educational effect of cooperative learning, which enables learners to make portfolio by taking advantage of their knowledge and skills acquired through practice, on an oral prophylaxis practice course in an attempt to stir up the spontaneous learning of learners, their learning interest and problem-solving skills. Methods : The selected dental hygiene students engaged in cooperative learning in oral prophylaxis practice III class in the second semester of their sophomore year by utilizing portfolio that was prepared by altering an inclusive dental hygiene practice model. They completed all the 15-week practice course, and then their portfolio was evaluated. They were divided into eight nonequivalent groups whose members were all different in academic standing, and their learning strategies and academic self-efficacy were checked before and after the instruction was provided. And their satisfaction with the class was investigated after the instruction was provided. Results : 1. There were significant gaps to $0.36{\pm}0.07$ in the charge of learning strategies after they engaged in cooperative learning(p<0.01). There were the broadest differences in cognitive strategies to 3.61, followed by metacognitive strategies to 3.19, and significant differences were found in all the subfactors(p<0.01). 2. There were significant gaps in the charge of self-efficancy to $0.13{\pm}0.06$ after they engaged in cooperative learning(p<0.01). There were the widest differences in self-regulating efficancy to 3.49, followed by confidence to 3.03 and task difficulty preference to 2.97, and significant differences were found in all the subfactors(p<0.01). 3. When their satisfaction level was analyzed after engaging in cooperative learning, there were significant gaps to 3.94 in the satisfaction level with all of the lectures(p<0.01). There were significant gaps in the satisfaction level with lecture to 4.20, with ensuring academic achievement to 4.13 and with cooperative learning to 3.48 (p<0.01). Conclusions : The above-mentioned findings indicated that cooperative learning had a positive impact on the learning strategies, academic self-efficacy and class satisfaction of the learners, and this study is expected to lay the foundation for the development of new teaching methods for dental hygiene.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1468-1477
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• 2011

Central government and local self-governing bodies are actively promoting bicycle-riding as a solution for transportation, environment, energy and health. They put lot of efforts in the practice of bicycle-related policies such as building bicycle-related infrastructure and creating task force team to improve the bicycle-related systems. However, there is no substantive improvement in the city rail operation agencies regarding the bicycle-related facilities and operation. The expansion of bicycle-related infrastructure in city rail stations is urgently required considering the increase in demands from the bicycle-riders for the facility and bicycle-related service improvement. Accordingly, this study suggests a bicycle-riding vitalization plan linking the city rail and bicycle by providing with a bicycle custody place in the city rail stations which will have comprehensive convenience facilities including the safe-keeping facility for bicycles.

• Journal of Industrial Technology
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• v.17
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• pp.255-260
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• 1997

The analysis of eigenvalue and eigenvector is a crucial procedure for many electromagnetic computation problems. Although it is always the case in practice that only selected eigenpairs are needed, computation of eigenpair still seems to be a time-consuming task. In order to compute the eigenpair more quickly, there are two resorts: one is to select a good algorithm with care and another is to use parallelization technique to improve the speed of the computing. In this paper, one of the best eigensolver, the Davidson method, is parallelized on a cluster of workstations. We apply this scheme to a ridged waveguide design problem and obtain promising linear speedup and scalability.

• Journal of Information Science Theory and Practice
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• v.3 no.3
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• pp.64-74
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• 2015

Despite the number of developed theories, it still remains a difficult task for some established and emerging scholars in various academic fields to clearly articulate new theories from research studies. This paper reviews and collates the views of scholars on what a theory is and how a good theory can be developed. It explains the concept of a theory, and the different components that make up a theory. The paper discusses the different processes of theory development by emphasizing what theory is and what theory is not. This review found that scholars differ in their definition of a theory, which leads to using terms such as model, paradigm, framework, and theory interchangeably. It found the lack of theoretical constructs in a study to be one of the factors which explains why articles are rejected for publication. This paper may be of benefit to established researchers who may be struggling with theory development, and especially younger academics who are the future of scholarship in various academic fields, particularly in information science.

• Research in Mathematical Education
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• v.4 no.2
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• pp.63-77
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• 2000

The purpose of this article is to devise the activities based on van Hiele levels of geometric thought using computer software, Geometer\\\\`s Sketchpad(GSP) as a tool. The most challenging task facing teachers of geometry is the development of student facility for understanding geometric concepts and properties. The National Council of teachers of Mathematics(Curriculum and Evaluation Standards for School Mathematics, 1991; Principles and Standards for School Mathematics, 2000) and the National Re-search Council(Hill, Griffiths, Bucy, et al., Everybody Counts, 1989) have supported the development of exploring and conjecturing ability for helping students to have mathematical power. The examples of the activities built is GSP for students ar designed to illustrate the ways in which van Hiele\\\\`s model can be implemented into classroom practice.

• Journal of the Ergonomics Society of Korea
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• v.23 no.3
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• pp.53-72
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• 2004

Today we are observing a lot of injuries, casualties, and property losses that are mainly caused by the defects of products. In order to derive safety designs, which minimize the possibility of such product liability-related accidents, we need to take into account the user-product interaction as an important part of the danger factor analysis. Existing risk analysis techniques, however, have some limitations in detecting comprehensive danger factors that are peculiarly involved in human errors and the functional defects of products. Researches on danger factor analysis regarding the user-product interaction have been carried out actively in ergonomics. In this paper, we suggest a novel product risk analysis technique, which is more objective and systematic compared to the previous ones, by combining a modified TAFEI (Task Analysis For Error Identification) technique with SASA (Systematic Approach to Accident Scenario Analysis) technique. By applying this technique to the product design practice in industry, corporations will be able to improve the product safety, consequently strengthening the competitiveness.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.2
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• pp.45-51
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• 2011

The article specified in aviation legislation, 'The captain has the final authority and responsibility in flight safety' could be one reason running counter to applying "Vertrauensgrundsatz". In practice, however, captains do not have professional skills in every task and they should distribute duties and responsibilities to flight attendents and other staffs to operate the flight as safely and efficiently as possible. Therefore, in aviation, fair criterion, namely, "Vertrauensgrundsatz" is necessary to balance between efficiency and legal interest for participants. In addition, when it comes to mutual trust of duty which was the starting point of this study, the standard in mutual advice or interference must be based on the duty specified in air law and flight regulations. Also, pervasive trust will not only be attributed to joint responsibility but an act that cannot be trusted.

• The Journal of Korean Physical Therapy
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• v.17 no.4
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• pp.493-504
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• 2005

The purpose of this study is to determine the effect of constraint-induced movement therapy on the involved hand function and ADL in stroke patients. Five subjects with fixing unaffected arms by CIMT were assigned to the experimental patient group and the other five patients to control group without fixing unaffected arms. The function of hand for both groups were evaluated by using Jebsen-Taylor hand function test and ADL for both groups were evaluated by FIM(Functional Independence Measure) before and after task practice. In conclusion, results of this study showed that improved hand function and ADL by CIMT in stroke patients. We concluded that CIMT can improved the involved hand function and ADL in stroke patients.

• Journal of Electrical Engineering and Technology
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• v.4 no.2
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• pp.149-158
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• 2009

It is important to derive reliable parameter values in the measurement-based load model development of electric power systems. However parameter estimation tasks, in practice, often face the parameter identifiability issue; whether or not the model parameters can be estimated with a given input-output data set in reliable manner. This paper introduces concepts and practical definitions of the local identifiability of model parameters. A posteriori local identifiability is defined in the sense of nonlinear least squares. As numerical examples, local identifiability of third-order induction motor (IM) model and a Z-induction motor (Z-IM) model is studied. It is shown that parameter ill-conditioning can significantly affect on reliable parameter estimation task. Numerical studies show that local identifiability can be quite sensitive to input data and a given local solution. Finally, several countermeasures are proposed to overcome ill-conditioning problem in measurement-based load modeling.