• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.199-202
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• 2006

The objective of this study is to propose methods of controlling the wake behind a sphere for drag reduction using the suboptimal control theory and surrogate management framework, respectively. The Reynolds numbers considered is 300 at which the base flow is unsteady planar symmetric. Given the cost function defined as the square of the difference between the target pressure (potential-flow pressure) and real flow pressure on the sphere surface, the suboptimal control makes the flow steady axisymmetric and produces drag reduction. Based on the actuation profile from the suboptimal control, the optimal wavy actuation profile is obtained using the surrogate management framework and produces drag reduction.

• Journal of Information Technology Applications and Management
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• v.21 no.3
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• pp.53-64
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• 2014

It is important to keep learners' feeling positive during learning to enhance learning performance. According to flow theory,challenge-skill balance is a precondition for flow experience: Learners feel anxiety when the challenge of learning is higher than their ability, feel boredom when the challenge of learning is lower than learners' ability, and engage in flow status when the challenge of learning matches the learners' ability. However, the current empirical study reveals that emotions related to enjoyment may appear when the learners' skill is equal to or higher than the learning challenge. Nevertheless, boredom emotion may appear when learners perceive the courses are difficult but unimportant. These empirical survey results revealed the necessary of rethinking the appearance of boredom and enjoyment emotions in computer education.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.243-243
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• 1996

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1989.10a
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• pp.51-51
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• 1989

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.471-474
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• 2003

An attempt was made to evaluate on water supply capability of river management flow of four agricultural dam at the Yongsan River which is required instream flow because of water pollution. As a result, supply capability of agricultural use was sufficient, but supply capability of river management flow was insufficient.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.423-426
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• 2004

Costs of public rental housing development project consist on various kinds of profits and expenses such as national housing fund, rental cost, construction cost, financing cost. Therefore, project would not be executed without minute management and precise prediction about each item. Cash (low prediction and analysis are necessary to grasp current situation of project, because construction project which is conducted for a long period has fluent risks and inflows and outflows of cash. Although cash flow analysis has been conducted, cash flow has never been expected and managed. General matters to expect cash flow can be known by actual results and literatures. Hut there is no thesis which is studied about risk to enhance precision of expectation of cash flow. As existing thesises studied the risk about whole project, we haven't known precise relations of cash flow and project. Therefore, in this study, we are supposed to analysis and distinguish risk facts which can affect each item of cash flow for precise cash flow expectation and management of public rental housing development project.

• Journal of Korean Society on Water Environment
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• v.31 no.2
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• pp.196-208
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• 2015

This study analyzed the characteristics of sewer flow and its water quality, and investigated changes in the characteristics in three areas where the sewer rehabilitation projects have been carried out. In S1 area, the patterns of the flow became regular and the range of the fluctuation decreased after the sewer rehabilitation. The flow and its BOD concentration increased. The infiltration/inflow and exfiltration showed clear distinction before and after the sewer rehabilitation in this area. In S2 area, the patterns and the range of the fluctuation of the flow made no differences before and after the sewer rehabilitation. The flow decreased slightly and its BOD concentration increased considerably after the sewer rehabilitation. Big decrement in stormwater inflow but small in exfiltration appeared in this area. In S3 area, the patterns and the range of the fluctuation of the flow made no differences before and after the sewer rehabilitation. The flow decreased slightly and its BOD concentration increased in a small rate in this area.

• Knowledge Management Research
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• v.13 no.1
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• pp.13-24
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• 2012

Unlike the traditional belief that knowledge flows along the formal reporting procedures, recent social network research has reported the importance of informal social networks which may play a critical role as the real knowledge conduits. In fact, as a complementary approach of utilizing knowledge management systems (KMSs), many firms have focused on managing informal knowledge flow through which to acquire and transfer valuable knowledge in a fast and effective way. In a case of global companies that have newly developed foreign branches or subsidiaries, due to cultural or institutional differences and lack of understanding of knowledge management and its benefits, they often have difficulties in activating knowledge sharing in local branches. In these situations, diagnosing organizational knowledge flow through SNA can be a first step to solve the problems. Therefore, in this paper, I report on the result of case study on a foreign branch of "A" global company by identifying organizational knowledge paths. Based on the results of the diagnosis, some implications and insights for building knowledge management (KM) strategy specified for a newly developed foreign branch will also be discussed.

• Quality Improvement in Health Care
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• v.7 no.2
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• pp.244-261
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• 2000

Background : In order to cope with changes in the management environment at hospitals, increased interests are drawn in patient foodservice system on Continuous Quality Improvement Activity as the method of approaching a quality food service and effective management. Thus, as a part of this activity, this study was conducted to evaluate job flow improvement that was already performed and the results of that process at the dietetic department of a university hospital, focusing on improving management. Method : On February 15 of 1998. the dietetic department formed a job flow-improvement to decide on the priority of job flow improvement, and prepared specific action strategies and schedule of the priority: after a 5 month process period, job improvement achieved on June 15. 1998. Also, economic achievement of the task was evaluated through labor productivity analysis and cost-benefit analysis. Results : The patient food service system which was managed decentralized at the present hospital was centralized, some steps of the food service process were integrated, and quality of patient food was improved. Also, as a solution of the problems expected when conducting job flow improvement was made on food service equipments and utensils. The result of evaluating the job flow improvement that labor productivity improved by 18.2% compared to before the improvement and the result of the analysis of cost-benefit showed that Benefit-Cost (B/C) ratio was 2.22. showing financial merit on the investment. Conclusions : Continuous Quality Improvement Activity needs to be initiated and conducted in the future in various areas of hospital foodservice system in order to actively adopt to ever changing hospital management environment. In order to achieve this goal, many researches and more efforts need to be put in by people in charge of hospital food service management, and interests and support are needed from hospital policy makers.

• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.167-175
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• 2010

The ubiquitous transportation system environments make it possible to collect each vehicle's position and velocity data and to perform more sophisticated traffic flow management at the individual vehicle or platoon level through vehicle to vehicle (V2V) and vehicle to infrastructure (V2I) communication. It is necessary to develop a traffic flow management scheme to take advantage of the ubiquitous transportation system environments. This paper proposes an algorithm to advise the optimal speed for each vehicle according to the traffic flow condition. The algorithm aims to stabilize the traffic flow by advising the equilibrium speed to the vehicles speeding or crawling under freely flowing condition. And it aims to prevent or at least alleviate the shockwave propagation by advising the optimal speed that should dampen the speed drop under critical flow conditions. This paper builds a simulation testbed and performs some simulation experiments for the proposed algorithm. The proposed algorithm shows the expected results in terms of travel time reduction and congestion alleviation.