• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제13권1호
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• pp.41-53
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• 2009

A primal-dual interior point method(IPM) not only is the most efficient method for a computational point of view but also has polynomial complexity. Most of polynomialtime interior point methods(IPMs) are based on the logarithmic barrier functions. Peng et al.([14, 15]) and Roos et al.([3]-[9]) proposed new variants of IPMs based on kernel functions which are called self-regular and eligible functions, respectively. In this paper we define a new kernel function and propose a new IPM based on this kernel function which has $O(n^{\frac{2}{3}}log\frac{n}{\epsilon})$ and $O(\sqrt{n}log\frac{n}{\epsilon})$ iteration bounds for large-update and small-update methods, respectively.

• 인터넷정보학회논문지
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• 제6권2호
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• pp.37-47
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• 2005

대부분 소프트웨어 규모 추정 기법들은 사용자에게 제공될 기능에 기반을 두고 있으며, 기능에 대한 점수를 부여하는 과정에서 복잡도를 함께 고려하고 있다. 완전기능점수 기법은 데이터 처리, 실시간 시스템과 알고리즘 소프트웨어 등 광범위한 분야에 적용되는 장점을 갖고 있는 반면에 규모를 추정하는데 필요한 기능 요소들에 대한 가중치를 부여하지 않는 단점도 갖고 있다. 본 논문은 신규로 개발되는 프로젝트와 유지보수 프로젝트들에 적용되는 완전기능점수 계산 방법에 각기능 요소들에 대한 복잡도를 고려하여 소프트웨어 규모를 추정할 수 있는 방법을 제안하였다. 이를 위해 기능 점수 기반으로 실측된 데이터를 이용하여 제안된 방법의 타당성을 검증하였다. 검증한 결과, 소프트웨어의 규모 추정에 사용되는 속성들인 기능 요소들에 다른 가중치를 적용하였을 경우 보다 좋은 규모 추정이 가능하였다.

• 전기학회논문지
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• 제57권7호
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• pp.1290-1294
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• 2008

We present a novel deblurring algorithm for bi-level images blurred by some parameterizable point spread function. The proposed method iteratively searches unknown parameters in the point spread function and noise-to-signal ratio by minimizing an objective function that is based on the binariness and the difference between two intensity values of restoring image. In simulations and experiments, the proposed method showed improved performance compared with the Wiener filtering based method in terms of bit error rate after segmentation.

• Structural Engineering and Mechanics
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• 제45권5호
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• pp.595-611
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• 2013

This paper aims to compare three collocation point methods associated with the odd order stochastic response surface method (SRSM) in a systematical and quantitative way. The SRSM with the Hermite polynomial chaos is briefly introduced first. Then, three collocation point methods, namely the point method, the root method and the without origin method underlying the odd order SRSMs are highlighted. Three examples are presented to demonstrate the accuracy and efficiency of the three methods. The results indicate that the condition that the Hermite polynomial information matrix evaluated at the collocation points has a full rank should be satisfied to yield reliability results with a sufficient accuracy. The point method and the without origin method are much more efficient than the root method, especially for the reliability problems involving a large number of random variables or requiring complex finite element analysis. The without origin method can also produce sufficiently accurate reliability results in comparison with the point and root methods. Therefore, the origin often used as a collocation point is not absolutely necessary. The odd order SRSMs with the point method and the without origin method are recommended for the reliability analysis due to their computational accuracy and efficiency. The order of SRSM has a significant influence on the results associated with the three collocation point methods. For normal random variables, the SRSM with an order equaling or exceeding the order of a performance function can produce reliability results with a sufficient accuracy. The order of SRSM should significantly exceed the order of the performance function involving strongly non-normal random variables.

• Structural Engineering and Mechanics
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• 제42권2호
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• pp.175-189
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• 2012

This paper presents an algorithm for structural reliability with the response surface method. For this aim, an approach with three stages is proposed named as improved response surface method. In the algorithm, firstly, a quadratic approximate function is formed and design point is determined with First Order Reliability Method. Secondly, a point close to the exact limit state function is searched using the design point. Lastly, vector projected method is used to generate the sample points and Second Order Reliability Method is performed to obtain reliability index and probability of failure. Five numerical examples are selected to illustrate the proposed algorithm. The limit state functions of three examples (cantilever beam, highly nonlinear limit state function and dynamic response of an oscillator) are defined explicitly and the others (frame and truss structures) are defined implicitly. ANSYS finite element program is utilized to obtain the response of the structures which are needed in the reliability analysis of implicit limit state functions. The results (reliability index, probability of failure and limit state function evaluations) obtained from the improved response surface are compared with those of Monte Carlo Simulation, First Order Reliability Method, Second Order Reliability Method and Classical Response Surface Method. According to the results, proposed algorithm gives better results for both reliability index and limit state function evaluations.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2325-2330
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• 2005

A potential field method for solving the problem of path planning based on global and local information for a mobile robot moving among a set of stationary obstacles is described. The concept of various method used path planning is used design a planning strategy. A real human living area is constructed by many moving and imminence obstacles. Home service mobile robot must avoid many obstacles instantly. A path that safe and attraction towards the goal is chosen. The potential function depends on distance from the goal and heuristic function relies on surrounding environments. Three additional combined methods are proposed to apply to human living area, calibration robots position by measured surrounding environment and adapted home service robots. In this work, we proposed the application of various path planning theory to real area, human living. First, we consider potential field method. Potential field method is attractive method, but that method has great problem called local minimum. So we proposed intermediate point in real area. Intermediate point was set in doorframe and between walls there is connect other room or other area. Intermediate point is very efficiency in computing path. That point is able to smaller area, area divided by intermediate point line. The important idea is intermediate point is permanent point until destruction house or apartment house. Second step is move robot with sensing on front of mobile robot. With sensing, mobile robot recognize obstacle and judge moving obstacle. If mobile robot is reach the intermediate point, robot sensing the surround of point. Mobile robot has data about intermediate point, so mobile robot is able to calibration robots position and direction. Third, we gave uncertainty to robot and obstacles. Because, mobile robot was motion and sensing ability is not enough to control. Robot and obstacle have uncertainty. So, mobile robot planed safe path planning to collision free. Finally, escape local minimum, that has possibility occur robot do not work. Local minimum problem solved by virtual obstacle method. Next is some supposition in real living area.

• 한국컴퓨터정보학회논문지
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• 제14권12호
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• pp.225-232
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• 2009

소프트웨어 규모 측정에 국제표준(IFPUG, FPA)에 기반한 기능점수 방식은 개발자 관점이 아닌 사용자 관점의 접근이라는 장점으로 널리 활용되고 있다. 그러나 현재의 기능점수 측정 방식은 복잡도 적용에서의 상한이 존재하는 등 문제점을 내포하고 있다. 본 논문에서는 이러한 복잡도 상한의 문제를 극복하고, 회귀식을 내장하고 있어 쉽게 소프트웨어 규모를 측정할 수 있으며, 특히 대형 애플리케이션에도 적용할 수 있는 개선된 기능점수 측정모델을 제시한다. 조직내에서 운영중인 10개 애플리케이션에 적용하여 적합성을 평가한 결과, 제시한 개선 모형이 기존의 FPA(Function Point Analysis) 방식보다 LOC(Line of Code) 규모를 비교하여 상관관계가 더 높은 장점을 확인할 수 있었다.

• Journal of applied mathematics & informatics
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• 제27권5_6호
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• pp.981-1000
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• 2009

This paper considers asset liability management problems when their deterministic equivalent formulations are general nonlinear optimization problems. The presented approach uses a nonmonotone trust region strategy for solving a sequence of unconstrained subproblems parameterized by a scalar parameter. The objective function of each unconstrained subproblem is an augmented penalty-barrier function that involves both primal and dual variables. Each subproblem is solved approximately. The algorithm does not restrict a monotonic decrease of the objective function value at each iteration. If a trial step is not accepted, the algorithm performs a non monotone line search to find a new acceptable point instead of resolving the subproblem. We prove that the algorithm globally converges to a point satisfying the second-order necessary optimality conditions.

• ETRI Journal
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• 제39권1호
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• pp.76-86
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• 2017

In this study, we propose an automatic contrast enhancement method based on transfer function modification (TFM) by histogram equalization. Previous histogram-based global contrast enhancement techniques employ histogram modification, whereas we propose a direct TFM technique that considers the mean brightness of an image during contrast enhancement. The mean point shifting method using a transfer function is proposed to preserve the mean brightness of an image. In addition, the linearization of transfer function technique, which has a histogram flattening effect, is designed to reduce visual artifacts. An attenuation factor is automatically determined using the maximum value of the probability density function in an image to control its rate of contrast. A new quantitative measurement method called sparsity of a histogram is proposed to obtain a better objective comparison relative to previous global contrast enhancement methods. According to our experimental results, we demonstrated the performance of our proposed method based on generalized measures and the newly proposed measurement.

• 정보처리학회논문지D
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• 제15D권3호
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• pp.375-386
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• 2008

최근 정보시스템 개발 패러다임이 객체지향 및 컴포넌트 기반으로 변해가고 있으며 이러한 방법론이 소프트웨어 산업계를 주도하고 있다. 소프트웨어 비용측정 분야도 이러한 변화에 적응하기 위해서 OO 환경에 적합한 비용 측정 모델로의 전환이 요구되고 있으며 실제 UCP 기법 등 객체지향 개념의 기능점수 연구가 진행되고 있다. 특히 객체지향 기능점수 측정 기법은 사용사례 중심으로 개발 프로젝트 초기에 적용 가능하고, 개발 진행 단계별 소프트웨어 산출물에 따라 생명주기 전체에 걸쳐서 적용 가능하고, UML 표기법에 의한 사용자와 의사소통으로 이해가 항상 가능하기 때문에 LOC 및 기존 기능점수 측정 기법의 한계를 극복하는 장점이 있다. 따라서 본 논문은 최근 객체지향 정보시스템 개발 환경에서 널리 사용되고 있는 UML 표기법 및 국방 CBD 방법론 절차에 의한 정보시스템 개발 프로젝트 진행에 따라 초기단계 시점(ROFP)과 분석단계 시점(AOFP)에서 기능점수를 측정하며, 전통적인 FPA 모델과 객체지향 FPA 모델을 통해 UML 모델링과 산출물을 기반으로 한 유스케이스와 클래스의 상관도 분석에서 서비스 기능과 객체/클래스 기능을 식별하고 기능점수를 구하는 측정기법을 제안한다. 무엇보다 전통적인 기능점수 측정 기법인 IFPUG-CPM 및 소프트웨어 대가기준의 기능점수 측정기법을 개선하여 객체지향 정보시스템 개발에 적합한 기능점수 측정 프로세스를 제시하고 사례연구를 통한 적합성 평가 결과를 제시한다.