• Journal of Energy Engineering
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• v.11 no.3
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• pp.194-202
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• 2002

In this paper, we simulate the power system transient stability of Kwang Yang steel works using object-oriented programming (OOP). OOP is a more flexible method than procedural programming. There are several advantages in dynamic system simulation using OOP, The maintenance and repair of program are easy because it is sufficient to modify necessary parts which correspond to the change of system without overall change of program. We have implemented a graphical man-machine interface (MMI) that can be used draw one-line system diagram and analyze power flow and dynamic stability. The implemented MMI also provide a graphical viewer that display dynamic stability analysis results by mouse event handling. The proposed method have been applied to Kwang Yang steel works network for on-line dynamic stability analysis. The dynamic behaviour of 17 synchronous generators and 25 synchronous motors has been studied in the Kwang Yang network.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.2
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• pp.119-129
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• 2010

Many algorithms for processing LIDAR data have been developed for diverse applications not limited to patch segmentation, bare-earth filtering and building extraction. However, since we cannot exactly know the true locations of individual LIDAR points, it is difficult to assess the performance of a LIDAR data processing algorithm. In this paper, we thus attempted the performance assessment of the segmentation algorithm developed by Lee (2006) using the LIDAR data generated through simulation based on sensor modelling. Consequently, based on simulation, we can perform the performance assessment of a LIDAR processing algorithm more objectively and quantitatively with an automatic procedure.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.713-713
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• 2012

그동안 사회적 여러 갈등의 갈등 조정을 위한 연구나 기술들은 주로 갈등발생원인들 중 법/제도적이나 정책추진 방법론 등 한 두 가지측면을 고려하여 평면적 분석을 시도하는 것이 대부분이고 특정지역 및 사례에 제한적으로 적용되는 것이 일반적이었다. 이와 같은 갈등 조정의 한계를 극복하기 위해 최근에는 이해당사자의 참여를 유도하고 공학적으로 접근하여 여러 대안 및 시나리오에 대해 모색할 수 있는 공영시각모형이 소개되면서 많은 정책결정과 수자원관리, 수질관리 분야 등에 널리 활용되고 있다. 하지만 객체지향을 내세우고 있는 공영시각모형은 신속한 모의 및 쉽게 모형을 다룰 수가 있다는 장점이 있으나, 공간적인 분석 및 표현은 불가능하다는 단점을 가지고 있다. 이에 본 연구에서는 ArcGIS를 기반으로 HEC-RAS와 연계하여 대상지역의 선 면적 개념의 치수적인 문제점을 도출시켜 이해당사자들에게 인식 및 이해시킬 수 있도록 하였으며, 댐 규모나 다른 대안이 수립되는 경우 이에 따른 수위저감효과와 홍수범람모의 및 홍수피해액 등을 제시할 수 있도록 개발하였다. 모형의 정확성, 신속성 및 다른 지역에서의 적용성 등을 확인하기 위하여 한탄강댐 갈등사례가 있었던 임진강 유역에 적용하여 모의운영 하였다. 그 결과 가상의 여러 대안에 의한 각 결과를 잘 제시하고 있었으며, 댐 건설 갈등현안 중 치수부문에 적용되어 갈등 조정에 기여할 수 있을 것이라고 판단된다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.915-916
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• 2009

프로그램 개발 단계에서 프로그램을 수정할 경우, 전체 프로그램을 다시 평가하는 대신 수정한 부분과 그 부분에 영향 받는 부분만을 다시 평가하는 것이 점진 평가 방법이다. 본 논문에서는 의미 구조에 직접적으로 영향을 주는 변수의 값을 나타내는 속성을 중심으로 종속성을 표시하고, 여러 프로세서에서 병렬로 처리하는 대신 멀티쓰레딩 기능을 활용하여 객체 지향언어인 자바 언어에서 점진 평가를 동시에 효율적으로 수행할 수 있는 병행 점진 평가 방법을 제시하고 모의실험을 통해 병행 점진 평가 방법의 효율성을 분석한다.

• The Journal of the Korea Contents Association
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• v.16 no.9
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• pp.451-459
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• 2016

While an object detection algorithm plays a key role in many computer vision applications, it requires extensive computation to show robustness under varying lightning and geometrical distortions. Recently, some approaches formulate the problem in a classification framework and show improved performances in object recognition. Among them, random fern algorithm drew a lot of attention because of its simple structure and high recognition rates. However, it reveals performance degradation under the illumination changes and noise addition, since it computes patch features based only on pixel intensities. In this paper, we propose a new structure of combined random fern which incorporates depth information into the conventional random fern reflecting 3D structure of the patch. In addition, a new structure of object tracker which exploits the combined random fern is also introduced. Experiments show that the proposed method provides superior performance of object detection under illumination change and noisy condition compared to the conventional methods.

• The KIPS Transactions:PartB
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• v.11B no.6
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• pp.653-660
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• 2004

Object-oriented analysis-synthesis coding (OOASC) subdivides each image of a sequence into a number of moving objects and estimates and compensates the motion of each object. It employs a motion parameter technique for estimating motion information of each object. The motion parameter technique employing gradient operators requires a high computational load. The main objective of this paper is to present efficient motion parameter estimation techniques using the hierarchical structure in object-oriented analysis-synthesis coding. In order to achieve this goal, this paper proposes two algorithms : hybrid motion parameter estimation method (HMPEM) and adaptive motion parameter estimation method (AMPEM) using the hierarchical structure. HMPEM uses the proposed hierarchical structure, in which six or eight motion parameters are estimated by a parameter verification process in a low-resolution image, whose size is equal to one fourth of that of an original image. AMPEM uses the same hierarchical structure with the motion detection criterion that measures the amount of motion based on the temporal co-occurrence matrices for adaptive estimation of the motion parameters. This method is fast and easily implemented using parallel processing techniques. Theoretical analysis and computer simulation show that the peak signal to noise ratio (PSNR) of the image reconstructed by the proposed method lies between those of images reconstructed by the conventional 6- and 8-parameter estimation methods with a greatly reduced computational load by a factor of about four.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.10C
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• pp.1015-1026
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• 2002

As per increasing research interest in the field of collaborative computing in recent year, the importance of security issues on that area is also incrementally growing. Generally, the persistency of collaborative system is facilitated with conventional authentication and cryptography schemes. It is however, hard to meet the access control requirements of distributed collaborative computing environments by means of merely apply the existing access control mechanisms. The distributed collaborative system must consider the network openness, and various type of subjects and objects while, the existing access control schemes consider only some of the access control elements such as identity, rule, and role. However, this may cause the state of security level alteration phenomenon. In order to handle proper access control in collaborative system, various types of access control elements such as identity, role, group, degree of security, degree of integrity, and permission should be taken into account. Futhermore, if we simply define all the necessary access control elements to implement access control algorithm, then collaborative system consequently should consider too many available objects which in consequence, may lead drastic degradation of system performance. In order to improve the state problems, we propose a novel access control framework that is suitable for the distributed collaborative computing environments. The proposed scheme defines several different types of object elements for the accessed objects and subjects, and use them to implement access control which allows us to guarantee more solid access control. Futhermore, the objects are distinguished by three categories based on the characteristics of the object elements, and the proposed algorithm is implemented by the classified objects which lead to improve the systems' performance. Also, the proposed method can support scalability compared to the conventional one. Our simulation study shows that the performance results are almost similar to the two cases; one for the collaborative system has the proposed access control scheme, and the other for it has not.

• The Korean Journal of Applied Statistics
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• v.28 no.6
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• pp.1275-1288
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• 2015

A microscale weather analysis module (about 1km or less) is a microscale numerical weather prediction model designed for operational forecasting and atmospheric research needs such as radiant energy, thermal energy, and humidity. The accuracy of the module is directly related to the usefulness and quality of real-time microscale weather information service in the metropolitan area. This paper suggests an object based verification method useful for spatio-temporal evaluation of the accuracy of the microscale weather analysis module. The method is a graphical method comprised of three steps that constructs a lattice field of evaluation statistics, merges and identifies objects, and evaluates the accuracy of the module. We develop lattice fields using various evaluation spatio-temporal statistics as well as an efficient object identification algorithm that conducts convolution, masking, and merging operations to the lattice fields. A real data application demonstrates the utility of the verification method.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.11
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• pp.853-858
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• 2006

In this paper, we propose a practical method for hardware-accelerated rendering of the depth image-based representation(DIBR) of 3D graphic object using graphic processing unit(GPU). The proposed method overcomes the drawbacks of the conventional rendering, i.e. it is slow since it is hardly assisted by graphics hardware and surface lighting is static. Utilizing the new features of modem GPU and programmable shader support, we develop an efficient hardware-accelerating rendering algorithm of depth image-based 3D object. Surface rendering in response of varying illumination is performed inside the vertex shader while adaptive point splatting is performed inside the fragment shader. Experimental results show that the rendering speed increases considerably compared with the software-based rendering and the conventional OpenGL-based rendering method.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.4
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• pp.13-20
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• 2016

It is possible to implement an optical character recognition system using a high-resolution camera mounted on smart phones in the modern society. Further, characters extracted from the implemented application is possible to provide the voice service for the visually impaired person by using TTS. But, it is difficult for the visually impaired person to properly shoot the objects that character information are included, because it is very hard to accurately understand the current state of the object. In this paper, we propose a method of inducing an appropriate shooting for the visually impaired persons by using a smartphone gyro sensor. As a result of simulation using the implemented program, we were able to see that it is possible to recognize the more character from the same object using the proposed method.