• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.660-667
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• 2003

In this study, a Multiple Objective Mixed Integer Programming (MOMIP) Model is developed for sewer rehabilitation planning by considering cost, inflow/infiltration. A sewer rehabilitation planning model is required to decide the economic life of the sewer by considering trade-off between cost and inflow/infiltration. And it is required to find the optimal rehabilitation timing, according to the cost effectiveness of each sewer rehabilitation within the budget. To develop such a model, a multiple objective mixed integer programming model is formulated based on network flow optimization. The network is composed of state nodes and arcs. The state nodes represent the remaining life and the arcs represent the change of the state. The model consider multiple objectives which are cost minimization and minimization of inflow/infiltration. Using the multiple objective optimization, the trade-off between the cost and inflow/infiltration is presented to the planner so that a proper sewer rehabilitation plan can be selected.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.2
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• pp.53-61
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• 2018

Flow is an optimal psychological state that people experience when engaged in an activity that is both appropriately challenging to one's skill level, often resulting in immersion and concentrated focus on a task. Through the study model, we found that Flow can result in deep learning and high levels of learning performance.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.2
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• pp.129-138
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• 2003

The traveling salesman problem (TSP) is an NP-hard problem. As the number of nodes increases, it takes a lot of time to find an optimal solution. Instead of considering all arcs, if we select and consider only some arcs more likely to be included in an optimal solution, we can find efficiently an optimal solution. Arc candidate set is a group of some good arcs. For the Lack of study in the asymmetric TSP. it needs to research arc candidate set for the asymmetric TSP systematically. In this paper, we suggest a regression function determining arc candidate set for the asymmetric TSP. We established the function based on 2100 experiments, and we proved the goodness of fit for the model through various 787problems. The result showed that the optimal solutions obtained from our arc candidate set are equal to the ones of original problems. We expect that this function would be very useful to reduce the complexity of TSP.

• Journal of Digital Convergence
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• v.6 no.1
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• pp.123-135
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• 2008

In this study it is aimed to find out the relationship between the effective factors on learning motivation of the digital textbook. To carry on such exploration the learning motivation theory of Keller has been taken as the theoretical background. This is an experimental research with the data collected from 310 students who took the digital textbook class in the computer-mediated environment. It is compared and verified whether the factors causing learning motivation of the ARCS model embedded in the offline class influence on learner's motivation and achievement. With the outcomes, it has been tried to find out some practical suggestions for the achievement of the digital textbook. The results of the data show that the learning motivation of the digital textbook is significantly influence on the learning achievement.

• The Journal of Korean Association of Computer Education
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• v.13 no.5
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• pp.15-27
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• 2010

Project-based learning is an effective teaching method for improvement of academic achievement and problem-solving ability so that is often applied to programming education. However, a strategy of enhancing motivation is required by a course design considering a learning style of students for advantage of PBL to take effect. Yet, studies on considerations with learning style still lack, when designing project-based programming learning courses for improvement of learning motivation. This research aims to address issues for consideration in designing PBL programming course. Accordingly, we analyzed learning motivation's difference between learning style in PBL programming class. We designed PBL programming course focusing ARCS model, where students making simulation The Kolb Learning Style Inventory is used to determine learning preferences. To assess students' motivation, Keller's Course Interest Survey was used in a pre-post-test-design. The result indicates that pre-post students' motivation differed. Also, we found considerations through comparing difference of ARCS model's detailed elements between learning styles.

• Journal of Digital Convergence
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• v.20 no.1
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• pp.25-32
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• 2022

The purpose of this study was conducted to develop adult distance literacy education program and verify its effects. The program was developed through the examination on factors affecting online literacy education and necessary analysis and feedback. Pre- and post-tests analyzing the effects of distance literacy education measuring academic understanding factor, learner satisfaction and satisfactory levels on the academic were administered to 49 adult literacy learners before and after a distance literacy education course. Also, this paper try to explore learners who participated in distance literacy education experience, change and that meaning. The results of the content analysis on the program are summarized as follows. First, there were statistically significant differences regarding academic understanding factor, learner satisfaction and perceived learning outcome satisfaction variables since distance literacy education program which is based on ARCS model start. In addition, learners were satisfied with replaying the learning videos several times, and the improved ability to use smart devices. But they expressed regrets about not being able to go to school and the difficulty of using the devices. It means that distance literacy education based on the ARCS model draw a positive learning conclusion. On the basis of these results, suggestions for further research were discussed.

• Journal of the Korea Convergence Society
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• v.9 no.5
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• pp.257-267
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• 2018

The purpose of this study was to evaluate the effects of an ESP module program which combines Keller's ARCS model for the $1^{st}$ grade nursing students. Students' learning motivation and academic achievement were compared between an intervention group and a control group and their perception and subjective effects on the module program were identified. Quantitative data showed that the overall level of learning motivation in the intervention group was significantly higher than that in the control group (t=2.391, p=.019). No significant difference was found on the level of academic achievement between two groups (t=0.116, p=.098). Contents analysis on the qualitative data showed that ESP module program was interesting, effective, helpful for understanding clinical settings, and giving confidence and satisfaction. According to the result, it is assumed that the ESP module program which combines ARCS model can be effective in motivating the $1^{st}$ grade nursing students to learn nursing contents and English.

• Journal of Mechanical Science and Technology
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• v.16 no.1
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• pp.46-59
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• 2002

The main purpose of this study is to investigate the variation of tool electrode edge wear and machining performance outputs, namely, the machining rate (workpiece removal rate), tool wear rate and the relative wear, with the varying machining parameters (pulse time, discharge current and dielectric flushing pressure) in EDM die sinking. The edge wear profiles obtained are modeled by using the circular arcs, exponential and poller functions. The variation of radii of the circular arcs with machining parameters is given. It is observed that the exponential function models the edge wear profiles of the electrodes, very accurately. The variation of exponential model parameters with machining parameters is presented.

• Korean Management Science Review
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• v.17 no.2
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• pp.87-95
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• 2000

This paper presents two analytical approaches to determine the vehicle fleet size for container shuttle service. The shuttle service can be defined as the repetitive travel between the designated places during working period. In the first approach, the transportation model is adopted in order to determine the number of vehicles required. Its advantages and disadvantages in practical application are also discussed. In the second approach, a logical network which is oriented on job is transformed from a physical network which is focused on demand site. Nodes on the logical network represent jobs which include loaded travel, loading and unloading and arcs represent empty travel for the next jobs which include loaded travel, loading and unloading and arcs represent empty travel for the next job. Then a mathematical formulation is constructed similar to the multiple traveling salesman problem (TSP). A solution procedure is carried out based on the well-known insertion heuristic with the real world data.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.952-957
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• 1992

When the circuit-breaker switches off, an electric arc is established between the contacts. It is very important to understand the arc characteristics for the design of a circuit breaker. This article describes the theoretical analysis of the arc characteristics by means of energy integral method when convection dominated low current arcs are produced in the dual-airflow nozzle of a model interrupter. In order to investigate the arc radius, the average electric field strength and the arc voltage, the arc column is divided into two regions, and then the energy conservation equation is applied to the arc in each region together with the axial cold flow mass flux function, steady-state mass balance equation and Ohm's law. The results show good agreements with those of other researchers.