• The KIPS Transactions:PartB
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• v.8B no.4
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• pp.403-410
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• 2001

물체의 형상을 부호화하기 위한 베이스라인기반 기법을 개선하였다. 베이스라인 기반 기법은 2차원인 물체의 형상 데이터를 전환점(turning point)과 기준선(Baseline)으로 부터의 거리값으로 부호화하는 방식이다. 즉, 가로나 세로의 한 방향의 거리 값과 다른 방향의 전환점을 부호화하는 방식이다. 본 논문에서는 기존의 베이스라인 기반 기법의 성능을 개선하기 위한 방법을 제안하였다. 첫 번째 방법은 허용 왜곡과 비트율을 판단하여 가로나 세로로 기준점의 방향을 변화시킴으로서 부호화해야하는 점들과 전환점들의 개수를 감소시켜서 압축률을 높이는 것이다. 두 번째 방법은 기존의 부표본화에서 사용된 왜곡을 판단보다 더 세밀하게 판단하여 더 많은 종류의 부표본화를 가능케 함으로써 압축률을 높이는 방법이다. 제안하는 방법이 기존의 베이스라인 기반 부호화와 MPEG-4에서 채택하고 있는 CAE(Context-based Arithmetic Encoding)와 비교해 보았을 때 보다 우수한 성능을 보임을 모의실험을 통해 확인하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6C
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• pp.624-633
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• 2003

We propose a novel method of selecting key VOPs from MPEG-4 compressed domain without fully decoding the compressed data. Approximated shapes of VOPs are obtained from the shape coding mode and then VOPs are clustered by shape similarity to generate key VOPs. The proposed method reduces the computation time of shape approximation, compared with Erol's method. Nevertheless, the resulting VOPs have a good summarizing capability of a video sequence. NMHD (normalized mean Hausdorff distance) values are 2-means clustered to generate key VOPs. In the video search, the MHD of a query VOP from key VOPs are computed and the VOP with the lowest distance is returned. Tests on standard MPEG-4 test sequences show that the computational complexity is very low. Recursive clustering proved to be very effective for generating suitable key VOPs.

• International Journal of Highway Engineering
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• v.11 no.4
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• pp.9-15
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• 2009

This research presents the structural performance and an improving technique for flexural capacity of road safety facilities based on the damage cases by wind pressure. Among road safety facilities, a support frame of soundproofing walls is considered as a prototype structure and its corresponding structural behaviors and section design are performed mainly by analytical and experimental studies. On the basis of analytical results, glass fiber reinforced polymer(GFRP) with an epoxy matrix which is high stiffness-to-weight ratio was used for applied one of strengthening techniques and their results shows that support frame strengthened by GFRP is the most effective compared to other cases proposed in this research for advancing its flexural improvement, Finally, optimum section design was performed analytically to evaluate wind-resistance capacity and its result would be very useful for developing a practical design guideline for Road safety facilities under strong wind.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1D
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• pp.81-89
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• 2009

CM(Configuration Management) is a field of management that focuses on establishing and maintaining consistency of a product's performance and its functional and physical attributes with its requirements, design, and operational information throughout its life. Recently upcoming concept of CM, regardless of various definitions, consists of the organization and the process for value creation through project change management, value preservation by Risk, Project Management implementation by Change management. The CM provide a basis for, and a record of, the project's performance in meeting the scope, time, cost. Overseas international companies have already adopted the CM system and enjoyed the benefits arising from such systems. And the CM provides perspectives and insights applicable to all types of projects. This study presents the review on the current systems now in use at jobsites and known to be efficient, and the introduction and application of configuration systems now at big issue. Hereby indicates the connective system consisted of work process, change control and knowledge referring to the methods and actual cases as an effective promotion of CM.

• The Journal of the Acoustical Society of Korea
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• v.20 no.4
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• pp.12-16
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• 2001

To analyze the performance of array shape estimation techniques using auxiliary sensors, the appropriate number and the positions of auxiliary sensors are investigated. Also, a post-processing technique based on spline interpolation is proposed to improve the performance of array shape estimation. The simulation results showed that when auxiliary sensors are arranged uniformly, the performance of shape estimation is better than other arrangements of auxiliary sensors. Also, the proposed post-processing technique improved the performance of the existing shape estimation method, such as Kalman filter method.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.68-74
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• 2015

This paper describes about the efficiency improvement of switched reluctance generator (SRG) over the rated speed region. Since the current shape has a great influence on the loss of the machine, so the system efficiency can be improved by optimizing the current shape. In case the wide speed range application such as wind power and medium size hydraulic power generation, a method of switching angle control is suggested to obtain the wanted current shapes. In order to verify the method, the experimental platform is set up. The feasibility of the theory is verified by simulation and experimental results.

• Journal of the Korean Geotechnical Society
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• v.27 no.12
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• pp.127-136
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• 2011

The laboratory tests were performed to investigate the strength characteristic of shotcrete reinforced with improved shape steel fiber developed in this study. Two different type of tests, the flexural toughness test and the bending strength test, were conducted for analyzing shotcrete strengths using three types of specimens (unreinforced shotcrete, exiting steel fiber reinforced shotcrete, and new concept steel fiber reinforced shotcrete). The results of tests represented the advancement of the strength characteristic of shotcrete reinforced with improved shape steel fiber with respect to that of shotcrete reinforced with existing steel fiber.

• Journal of Korean Society of Steel Construction
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• v.16 no.6 s.73
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• pp.819-832
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• 2004

This study describes an efficient and facile method for configuration optimum design of structures. One of the ways to achieve numerical shape representation and the selection of design variables is using the design element concept. Using this technique, the number of design variables could be drastically reduced. Isoparametric mapping was utilized to automatically generate the finite element mesh during the optimization process, and this made it possible to easily calculate the derivatives of the coordinates of generated finite element nodes w.r.t. the design variables. For the structural analysis, finite element analysis was adopted in the optimization procedure, and two different techniques(the deterministic method, a modified method of feasible direction; and the stochastic method, a genetic algorithms) were applied to obtain the minimum volumes and section areas for an efficient configuration optimization procedure. Futhermore, spline interpolation was introduced to present a realistic optimum configuration that meet the manufacturing requirements. According to the results of several numerical examples(steel structures), the two techniques suggested in this study simplified the process of configuration optimum design of structures, and yielded improved objective function values with a robust convergence rate. This study's applicability and capability have therefore been demonstrated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.7
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• pp.637-646
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• 2010

A time-domain panel method based on the potential flow theory and the time-stepping method is developed to predict the steady/unsteady aerodynamic characteristics of FM07, which is the BWB (Blended-wing body) type MAV. In the aerodynamic analyses, we used two types of the initial model(Case I) and the improved model(Case II), which is moved the gravity center toward the rear and has larger aspect ratio. In the steady aerodynamic analyses, it is revealed that improved model has higher lift to drag ratio(L/D) and more stable pitch characteristic than those of the initial model. In the unsteady aerodynamic analyses for sudden acceleration motion similar to the launch phase of MAV, it seemed that there is a rapid increase of the lift coefficient after the launch and unsteady results are good agreed compare with steady results in just a few times. In the analysis for pitch oscillation motion, which is occurred at the cruise condition of the FM07, it shows that unsteady aerodynamic coefficients looped around steady results and the improved model has more sensitive aerodynamic characteristics.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.912-913
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• 2011

본 논문은 Yoke 형상 변화에 따른 EV-Relay 구동 액츄에이터의 동작특성에 대해 연구하였다. 요크는 기본 형상을 포함하여 3가지 형태이며, 각 형상에 대해 유한요소해석으로 동작특성을 계산하였다. 계산시간 단축을 위해 2차원 축대칭 모델을 이용하였고, 기계적 부하를 동작특성 계산과정에 포함하여 실제동작상태와 유사하게 표현하였다. 마지막으로, 요크 형상에 따른 3가지 모델의 계산결과를 비교하여 기존 모델보다 형상이 변화된 모델의 동작특성이 개선되었음을 확인하였다.