• Journal of the Korea Society of Computer and Information
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• v.15 no.9
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• pp.35-46
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• 2010

Sequential pattern mining is one of the essential data mining tasks, and it is widely used to analyze data generated in various application fields such as web-based applications, E-commerce, bioinformatics, and USN environments. Recently data generated in the application fields has been taking the form of continuous data streams rather than finite stored data sets. Considering the changes in the form of data, many researches have been actively performed to efficiently find sequential patterns over data streams. However, conventional researches focus on reducing processing time and memory usage in mining sequential patterns over a target data stream, so that a research on mining more interesting and useful sequential patterns that efficiently reflect the characteristics of the data stream has been attracting no attention. This paper proposes a mining method of sequential patterns over data streams with a gap constraint, which can help to find more interesting sequential patterns over the data streams. First, meanings of the gap for a sequential pattern and gap-constrained sequential patterns are defined, and subsequently a mining method for finding gap-constrained sequential patterns over a data stream is proposed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.671-678
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• 2006

In this study, to describe vehicle-structure dynamic interaction phenomena with 1/4 vehicle model, nonlinear Hertzian contact spring and nonlinear contact damper are adopted. The external loads acting on 1/4 vehicle model are selfweight of vehicle and geometry information of running surface. The constraint equation on contact surface is implemented by the Penalty method with stabilization and the reaction from constraint violation. To describe pitching motion of various vehicles two types of the displacement constraint equations are exerted to connect between car bodies and between bogie frames, i.e., the rigid body connection and the rigid body connection with pin, respectively. For the time integration of dynamic equations of vehicles and structure Newmark time integration scheme is adopted. To reduce the error caused by inadequate time step size, adaptive time-stepping technique is also adopted. Thus, it is expected that more versatile dynamic interaction phenomena can be described by this approach and it can be applied to various railway dynamic problems with low computational cost.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.213-214
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• 2008

이종망 핸드오버시 동종망 핸드오버를 저해하지 않고 시행하는 방안을 제안하였다. 해당 방법은 동종망의 인접기지국을 이용한 임계조건만을 적용하는 것으로 불필요한 핸드오버가 발생하는 경우를 제한하여 저전력 구동 기반으로 동작하기 적합하며 핸드오버 정책 등에서 적용할 수 있도록 기준 성능을 조건으로 이용하는 핸드오버를 제공할 수 있다. 해당방법의 적용으로 무선망의 경계지역을 구분하는 핸드오버 제공이 가능하고 잦은 핸드오버 발생을 억제하는 신뢰성 있는 서비스 품질을 기대할 수 있다.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.226-235
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• 2017

이 논문에서는 워핑 구속조건이 박벽 구조물의 비틀림 거동에 주는 효과를 확인하였다. Vlasov torsion theory를 통해 얻은 이론해 및 EDISON SW의 해석해를 St.Venent torsion theory를 통해 얻은 이론해와 비교하는 방법으로 그 영향을 확인하였다. 이를 통해 Clamped end조건이 단면의 형상 및 단면의 세부 파라미터에 따라 단면의 워핑발생을 제한하여 비틀림거동에 큰 영향을 미칠 수 있음을 확인했다.

• 월간 기계설비
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• no.11 s.208
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• pp.29-40
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• 2007

국가계약법 시행령이 개정됨에 따라 재정경제부는 공사계약 일반조건, 입찰조건, 입찰유의서 등 회계예규를 개정하고 지난 10월 12일부터 시행에 들어갔다. 개정된 시행규칙은 공사계약일반조건에서 설계서와 물량내역서 등의 범위에 대한 정의규정 보완/손해보험 관련 손해공제 포함/설계변경 관련 조문정리/설계변경 계약금액조정 제한대상 추가 및 입찰금액조정 규정 마련/특정규격의 자재별 가격변동에 따른 계약금액조정 관련 등이 개정되었고, 공사입찰유의서에는 입찰에 관한 서류의 열람 및 교부/입찰무효사유 보완/낙찰자가 부적격자로 판명된 경우 낙찰자 결정 방법 개선/조문정리 등이 개선되었다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.365-370
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• 1996

본 논문은 GIS를 이용하여 원자력 발전소 건설을 위한 최적의 부지 선택 방안을 연구한 것이다. 근래 고도 경제 성장에 따라 전력 사용량이 날로 증가되고 있으며 이에 따라 발전소의 추가 건설이 시급한 실정이다. 그러나 발전소 건설에 필요한 적지가 희소한 실정이며 정부의 국토이용 계획, 각종 개발 제한 사항에 의해 갈수록 제약을 받게 되어 부지 선정에 많은 어려움이 예상된다. 본 논문에서는 기존의 원자력 발전소 입지선정 절차를 근간으로하여 부지평가에 영향을 주리라 예상되는 지질, 골재원, 수송조건, 부지표고, 용수원, 해상조건, 접안조건 및 주변환경, 인구 분포 등의 부지평가 요소들을 중심으로 하고, GIS를 이용한 부지평가 항목의 분석을 통하여 원자력 발전소 부지의 최적 후보지를 결정하는 개념적 방안을 제시하였다.

• The Journal of the Acoustical Society of Korea
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• v.13 no.1E
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• pp.11-19
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• 1994

Hidden Markov Models (HMM's) with explicit state duration density (HMM/SD) can represent the time-varying characteristics of speech signals more accurately. However, such an advantage is reduced in relatively smooth state duration densities or ling bounded duration. To solve this problem, we propose HMM's with global path constraint (HMM/GPC) where the transition between states occur only within prescribed time slots. HMM/GPC explicitly limits state durations and accurately describes the temproal structure of speech simply and efficiently. HMM's formed by combining HMM/GPC with HMM/SD are also presented (HMM/SD+GPC) and performances are compared. HMM/GPC can be implemented with slight modifications to the conventional Viterbi algorithm. HMM/GPC and HMM/SD_GPC not only show superior performance than the conventional HMM and HMM/SD but also require much less computation. In the speaket independent isolated word recognition experiments, the minimum recognition eror rate of HMM/GPC(1.6%) is 1.1% lower than the conventional HMM's and the required computation decreased about 57%.

• Geophysics and Geophysical Exploration
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• v.10 no.4
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• pp.314-321
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• 2007

Recently, multi-dimensional joint inversion of geophysical data based on fundamentally different physical properties is being actively studied. Joint inversion can provide a way to obtaining much more accurate image of the subsurface structure. Through the joint inversion, furthermore, it is possible to directly estimate non-geophysical material properties from geophysical measurements. In this study, we developed a new algorithm for jointly inverting dc resistivity and seismic traveltime data based on the multiple constraints: (1) structural similarity based on cross-gradient, (2) correlation between two different material properties, and (3) a priori information on the material property distribution. Through the numerical experiments of surface dc resistivity and seismic refraction surveys, the performance of the proposed algorithm was demonstrated and the effects of different regularizations were analyzed. In particular, we showed that the hidden layer problem in the seismic refraction method due to an inter-bedded low velocity layer can be solved by the joint inversion when appropriate constraints are applied.

• Journal of the Korea Society of Computer and Information
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• v.10 no.3 s.35
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• pp.45-54
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• 2005

The existing access control models have the demerits that do not provide the limit function of using resources by time constraint, the restricted inheritance function as a superior role in role hierarchy, the delicate delegation policy and the limit function of using resources by the location information about a user for the access control in ubiquitous environment. This paper proposes an Extended-GTRBAC model is suited to the access control in ubiquitous environment by applying to sub-role concept of GTRBAC model that the application of resources can be restricted by the period and time and PBDM and considering the location information about a user on temporal constraint. The proposal model can restrict the inheritance of permission in role hierarchy by using sub-role, provide the delicate delegation policy such as user-to-user delegation, role to role delegation, multi-level delegation. multi-step delegation, and apply diverse and delicate access control policy which is suited the characteristic of ubiquitous environment by considering the location information about a user on temporal constraint.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.3
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• pp.285-291
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• 2003

Switched reluctance machine has much attention as a traction drive because of high efficiency, high power and DC series torque characteristics. But the motor has to have a regenerative mode when it is adopted in electric vehicle and current divergence during the regeneration makes difficulties in the control. This paper proposes a reference current limitation strategy for a stable regeneration based on simulations and experimented tests. The motor is operated with conventional current limit and switching angle control method in motoring mode. Simulations and experiments are excuted to verify the feasibility of the proposed method.