• The Korean Journal of Applied Statistics
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• v.9 no.2
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• pp.161-169
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• 1996

In the design of the sampling, it is important to make a decision about the size of the sample to be selected from the population. We often have a problem to get the optical size of the sample to be considered for cost and time expended for selecting sample unit from highly skewed population. In this case, we give a graphical criterion with Take-all Stratum rate to choose a method and also illustrate the efficiency between the Neyman allocation and the cut-off method with real data.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.91-94
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• 2002

It is important to develop new effective technologies for increasing the interruption capacity and reducing the size of a GCB (Gas Circuit Breaker). It is not easy to test the real GCB model in practice as in theory. Therefore, a simulation tool based on a CFD (Computational Fluid Dynamics) algorithm has been developed to facilitate an optimization of the interrupter. But the choice of grid is not at all trivial in the complicated geometries like a GCB. In this paper, we have applied a CFD-CAD integration using Cartesian cut-cell method, which is one of the grid generation techniques for dealing with complex and multi-component geometries.

• The Transactions of the Korea Information Processing Society
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• v.6 no.7
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• pp.1955-1961
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• 1999

비디오 데이터는 비정형 데이터이고 정보의 양이 방대하기 때문에 내용기반 검색 방법이 필요하다. 비디오 데이터의 내용기반 검색을 위해서는 동영상 데이터의 색인이 필요한데, 일반적으로 비디오 색인을 하기 위한 시작점은 컷 검출이다. 본 논문에서는 컷 검출의 효율성을 향상시키기 위해서 컷 검출 과정 중 임계값이 동적으로 변화하는 동적 임계값 기법을 제안한다. 구현과 실험을 통하여 제안하는 방법이 기존의 방법보다 효율적임을 보였다. 6a A content-based search method is required for video which has an unformatted and huge size of data. The index technique is necessary for the content-based search of the video data. The first step of the video indexing is a cut detection. We propose a dynamic threshold method which changes a threshold value during the cut detection process. We demonstrate that the proposed method is more efficient than the existing methods.

• Proceedings of the Korea Society of Design Studies Conference
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• 2004.10a
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• pp.170-171
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.429-430
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• 2006

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.2
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• pp.113-122
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• 2013

Recently there has been increased interest for the portal and shallow tunnel for an eco-friendly tunneling method. Semi cut & cover tunnel excavation techniques applied to concrete slab and construction and a growing number of cases, but there is no load combinations and arch concrete cross section for the applicable standards. Therefore, in this study, ground conditions and tunnel overburden thickness, thickness of backfill, overburden surface slope angle changes to a variety of conditions in order to propose standards for the semi cut & cover method was performed numerical analysis. Regression analysis method to the analysis of the results of numerical analysis, and linear regression equations derived to classify and organize a rational, economical, and safe semi cut & cover tunneling method based proposed.

• Journal of KIISE:Information Networking
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• v.36 no.2
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• pp.98-107
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• 2009

In this paper, we propose a novel centralized energy-efficient clustering algorithm, called "MCCA : Max k-Cut based Clustering Algorithm for Wireless Sensor Networks." The algorithm does not use location information and constructs clusters via a distributive Max k-Cut based cluster-head election method, where only relative and approximate distance information with neighbor nodes is used and nodes, not having enough energy, are excluded for cluster-heads for a specific period. We show that the energy efficiency performance of MCCA is better than that of LEACH, EECS and similar to BCDCP's by simulation studies.

• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.609-616
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• 2005

Signature-based Intrusion Detection has many false positive and many difficulties to detect new and changed attacks. Alpha-cut is introduced which reduces false positive with a combination of signature-based IDS and machine learning-based IDS in prior paper [1]. This research is a study of a succession of Alpha-cut, and we introduce Beta-rick in which attacks can be detected but cannot be detected in single signature-based detection. Alpha-cut is a way of increasing detection accuracy for the signature based IDS, Beta-pick is a way which decreases the case of treating attack as normality. For Alpha-cut and Beta-pick we use XIBL as a learning algorithm and also show the difference of result of Sd.5. To describe the value of proposed method we apply Alpha-cut and Beta-pick to signature-based IDS and show the decrease of false alarms.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.564-569
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• 2005

Usually, Steel pipe grouting method or cut and cover method has been applied to tunnel with very shallow overburden or it is situated in valley. However, in case of lack of overburden height to reinforcement tunnel crown which is very difficult to construction. Also, application of cut and cover method that do not consider surrounding site condition causes popular enmity generation and environmental damage. It is the best alternative method that reduces the amount of excavated soil and excavate tunnel under ground to solve these problems. The tunneling method using cover structure which is to prevent a tunnel from collapse because this method can be reduce excavation area and construct tunnel under ground after set a cover structure and backfill ground. In this study, to know more effective structure type, comparative analysis was performed to behavior characters of slab and arch type construction that can be used to cover structure. Also a 2D and 3D numerical analysis have been performed to verify the stability of ground during excavation. As the result, the tunneling method using cover structure that it can be good alternative method for tunnel with shallow overburden and it through valley

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.10
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• pp.1341-1347
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• 2002

In order to improve efficiency of a system with three-dimensional flow characteristics, this paper presents a new method that overcomes three-dimensional effects by using two-dimensional CFD and neural network. The method was applied to shape optimization of cut-off in a multi-blade fan/scroll system. As the entrance conditions of two-dimensional CFD, the experimental values at the positions out of the inactive zone were used. The distributions of velocity and pressure obtained by two-dimensional CFD were compared with those of three-dimensional CFD and experimental results. It was found that the distributions of velocity and pressure have qualitative similarity. The results of two-dimensional CFD were used for teaming as target values of neural network. The optimal angle and radius of cut-off were determined as 71$^{\circ}$and 0.092 times the outer diameter of impeller, respectively. It is quantified in the previous report that the optimal angle and radius of cut-off are approximately 72$^{\circ}$and 0.08 times the outer diameter of impeller, respectively.