• Journal of Korea Water Resources Association
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• v.33 no.3
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• pp.289-298
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• 2000

In order to minimize the impact of water hammer In a pipeline, a determination of optimum position of hydraulic structures with best operation of pressure relief valve was explored at the Seobyun pumping station. Method of characteristics is used to simulate a surge impact originating from abrupt stop of pumping operation in a pipeline. Genetic algorithm shows a powerful capability in searching a global solution, especially for a nonlinear problem The application results suggests that the maximum positive pressure can be relaxed by decreasing the opening time of pressure relief valve, meanwhile the maximum negative pressure can be relaxed by increasing the opening time of pressure relief valve. This study shows that the integration of a genetic algorithm with a transient analysis technique such as method of characteristic can improve the design of hydraulic structure in a pipe network.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.1
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• pp.42-48
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• 2006

In this study, a repetitive response surface enhancement technique (RRSET) is proposed as a new system approximation method for the efficient multidisciplinary design and optimization (MDO). In order to represent the highly nonlinear behavior of the response with second order polynomials, RRSET introduces a design space transformation using stretching functions and repetitive response surface improvement. The tentative optimal point is repetitively included to the set of experimental points to better approximate the response surface of the system especially near the optimal point, hence a response surface with significantly improved accuracy can be generated with very small experimental points and system iterations. As a system optimizer, the simulated annealing, which generates a global design solution is utilized. The proposed technique is applied to several numerical examples, and demonstrates the validity and efficiency of the method. With its improved approximation accuracy, the RRSET can contribute to resolve large and complex system design problems under MDO environment.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.2 no.4
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• pp.190-199
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• 1990

The solution for wind drift current in a three-layered open sea region is derived using the Galerkin-Eigenfunction mothod. The presence of discontinuities in the vertical eddy viscosity required a definition of a scalar product which involves the summation of integrals defined over each layer. The expansion of fourth-order B-spline functions is used in determining eigenvalues and corresponding eigenfunctions. In a three-layered system a low value of eddy viscosity is prescribed within the pycnocline to represent the suppression of turburent intensity at the thermocline level. A high concentration of knots within the pycnocline is important in determining eigenfunctions and the associated eigenvalues accurately. Due to the global property of eigenfunctions nonphysical oscillations appear in the current profiles below the surface layer, particularly within the pycnocline.

• Journal of Engineering Education Research
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• v.12 no.2
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• pp.83-88
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• 2009

In this paper the author proposes a case study of a freshmen introduction to engineering design course ing LEGO Mindstorm NXT and analyzes the survey results of the course. The diffilculties are that this course should provide various aspects of design experiences to the students while not requiring the major knowledge and skills and it should attract the students to the engineering major. According to our case study LEGO mindstorm can be a good solution to this problem. The design experience with LEGO Mindstorm NXT provides students with various aspects of design experiences including defining problem, finding constraints and functions, exploring design space, and performing preliminary design, as well as fun. This paper also provides a project list that can be used for freshmen design experience including soccer game robots, line tracer, and vacuum cleaner etc.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4357-4378
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• 2017

In cooperative multi-relay networks, the relay nodes which are selected are very important to the system performance. How to choose the best cooperative relay nodes is an optimization problem. In this paper, multi-relay selection schemes which consider either single objective or multi-objective are proposed based on evolutionary algorithms. Firstly, the single objective optimization problems of multi-relay selection considering signal to noise ratio (SNR) or power efficiency maximization are solved based on the quantum bee colony optimization (QBCO). Then the multi-objective optimization problems of multi-relay selection considering SNR maximization and power consumption minimization (two contradictive objectives) or SNR maximization and power efficiency maximization (also two contradictive objectives) are solved based on non-dominated sorting quantum bee colony optimization (NSQBCO), which can obtain the Pareto front solutions considering two contradictive objectives simultaneously. Simulation results show that QBCO based multi-relay selection schemes have the ability to search global optimal solution compared with other multi-relay selection schemes in literature, while NSQBCO based multi-relay selection schemes can obtain the same Pareto front solutions as exhaustive search when the number of relays is not very large. When the number of relays is very large, exhaustive search cannot be used due to complexity but NSQBCO based multi-relay selection schemes can still be used to solve the problems. All simulation results demonstrate the effectiveness of the proposed schemes.

• Journal of Internet Computing and Services
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• v.4 no.1
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• pp.53-65
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• 2003

I/O processing speed of relatively sluggish storage devices incurs overall performance degradation in computer systems. As a solution to improve the situation, SAN(Storage Area Network) has been proposed. In order to utilize a SAN system more effectively, where storage devices are directly connected with a high speed network such as Fibre Channel, a proper management tool is needed. In this paper, we present a design and implementation of a performance monitoring and configuration management tool for the SANtopia system which supports global file sharing in the SAN environment The developed tool is to monitor the performance of the Linux hosts composing the SANtopia system and to manage the configuration of the hosts and storage devices. It also supports GUI(Graphic User Interface) environment using the JAVA programming language.

• Journal of Korea Port Economic Association
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• v.26 no.1
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• pp.234-258
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• 2010

This research attempts to explore the competitive advantage of the Busan New Port based on the comparative analysis against the major ports. The competitive environment of the global shipping business poses a variety of challenges for the port authorities. Pursuing the hub position in the Northeast Asia, Busan new port needs an in-depth competitive analysis against the major ports in Singapore and China. This research proposes the strategies to exploit the locational advantage of the port while upgrading the operational efficiency. The recent development of the information technology suggests a viable solution for the Busan port.

• Journal of Korea Game Society
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• v.5 no.4
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• pp.39-48
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• 2005

The gift coupon system was introduced in the AWP(Amusement With Prize) Game Industry in February 2002 to revitalize the sluggish domestic game industry and establish the cultural industry base. Today, however, speculations regarding these coupons are fast becoming a serious social issue. Therefore, this study proposes the establishment of the MCTF Management System as a possible solution to the analysis and resolution of the problem of gift coupons aimed at promoting the AWP Game Industry and ensuring its soundness as well as bridging the gap between the domestic and international game markets in terms of the industrial structure; thus securing global competitiveness. Unlike any other measure taken to date to prevent speculations, the MCTF Management System can eradicate problems related to coupons offered for free in the AWP Game Industry. This strategic system consists of Merchandise Coupon Management, Central Management, Tripartite Guarantee Management, and Fund Management System. Finally, this system is expected to help root out the problems related to gift coupons.

• 기술발표회
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• s.2006
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• pp.146-155
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• 2006

A study for damage degree and reduction programs of disaster was performed after collecting and analyzing the damage data by the type of flood damage resulting from the localized rainfall Gangwon area has been damaged by heavy localized rainfall between July 15 and 17 in 2006 Specially, a number of people was killed and much properties were lost in Inje, Yangyang and Pyeongchang area Recently, the damages by debris flow has been increased more than any other disaster causes, because heavy rainfall closed to about 100mm/hr by global warming in short time has been developed frequently. In other words, an area forming a highland has a potential debris flow Therefore, in this study, the damages data by debris flow in the area of Inje and Yangyang were collected and analyzed to consider the type of flood damage In future, it must be tried to find a complementary solution and establishing management system for debris flow when the civil construction begins

• The Journal of the Korea Contents Association
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• v.18 no.6
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• pp.564-573
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• 2018

External environment of enterprises are rapidly changing brought about mainly by global competition, cost and profitability pressures, and emerging new technology. In particular, frequent change of customer requirements is a tough challenge to manufacturing company. To cope with these challenges, a production planning and scheduling (PP&S) function might be established to provide accountability for both customer service and operational efficiency. PP&S deals with short-term decision making in the production process of whole supply chain. The task of PP&S is to seek a balance between customer orders and limited resources. At present, many PP&S software solutions have been utilized in many enterprises to generate a realistic production plan and schedule efficiently. The aim of this paper is to analyze the PP&S functionalities and its system architecture from the perspective of SCM (Supply Chain Management), and propose the PP&S solution classification framework to facilitate the comparison among various solutions.