• 한국정밀공학회지
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• 제10권1호
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• pp.89-99
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• 1993

A solid modeller was developed in this paper. Representation scheme of modelling is nonmanifold B-rep. While namy B-rep modellers use edges as basic element of modelling, this modeller is triangle-based. New modelling element, split triangle that is composed of 3 pure half-edges and has no information about the adjoining triangles, was defined to enlarge the range of representation. Corresponding algorithms for Boolean set operations were also developed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권10호
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• pp.2567-2586
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• 2012

Localization of sensor nodes is a key technology in Wireless Sensor Networks(WSNs). Trilateration is an important position determination strategy. To further improve the localization accuracy, a novel Trilateration based on Point In Triangle testing Localization (TPITL)algorithm is proposed in the paper. Unlike the traditional trilateration localization algorithm which randomly selects three neighbor anchors, the proposed TPITL algorithm selects three special neighbor anchors of the unknown node for trilateration. The three anchors construct the smallest anchor triangle which encloses the unknown node. To choose the optimized anchors, we propose Point In Triangle testing based on Distance(PITD) method, which applies the estimated distances for trilateration to reduce the PIT testing errors. Simulation results show that the PIT testing errors of PITD are much lower than Approximation PIT(APIT) method and the proposed TPITL algorithm significantly improves the localization accuracy.

• 한국학교수학회논문집
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• 제13권2호
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• pp.263-287
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• 2010

본 연구에서는 초등학생이 삼각형을 어떻게 정의하고 있으며, 삼각형인 예와 삼각형이 아닌 예의 식별 과정에서 나타난 학생들의 추론 유형을 조사하였다. 그리고 학생들의 추론 유형과 학생들의 기하적 수준이 어떤 관련성이 있는지 알아보았다. 연구 결과 대부분의 학생들은 세 개, 꼭짓점, 닫힌 도형, 직선성 등 도형의 본질적인 속성에 기초하여 삼각형을 식별하였으며, 몇 몇 학생들은 도형의 크기, 방향 등 도형의 비본질적인 속성에 기초하여 삼각형을 식별하였다. 특히 기하적 수준이 낮은 몇 몇 학생들은 도형의 전체적인 형태에 기초한 시각적 추론을 통하여 도형을 식별하였다.

• 한국정밀공학회지
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• 제14권2호
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• pp.136-144
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• 1997

Usually triangular patches are used to transfer geometric shape in Rapid Prototyping CAM system. STL, a list of triangles, is de facto standard in RP industry. Because STL does not have topological infoma- tion, it can cause errornous results. So STL should be verified before using. After adding support structures to anchor the part to the platform and to prevent sagging or distortion, slicing and layer by layer manufactur- ing process are done. But triangular patch is surface model and cannot provide sufficient information on geometry in the above processes. So, geometric modeling is necessary in verifying STL, adding support structures and slicing. It is natural that triangle based modeling is the best when tringular patches are used as input. Considering support structures, solid and faces coexist in RP process. Therefore non-manifold modeler is required. In this study, triangle based non-manifold geometric modeling is proposed for RP sys- tem consistent with STL input.

• Journal of Advanced Marine Engineering and Technology
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• 제21권5호
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• pp.571-578
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• 1997

This paper presents a method for designing a control system to stand upright inverted triangle. A linearized model is obtained form the nonlinear system by Taylor series expansion and a state controller is designed based on the model. After implementing the control system which is combined control law and estimator with reference input, experiments are carried out to stand upright inverted triangle at any angluar position.

• Journal of the Korean Data and Information Science Society
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• 제18권3호
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• pp.793-801
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• 2007

For multiply Type-II censored samples from a half-triangle distribution, the maximum likelihood method does not admit explicit solutions. In this case, we propose some explicit estimators of the location parameter in the half-triangle distribution by the approximate maximum likelihood methods. We compare the proposed estimators in the sense of the mean squared error for various censored samples.

• Journal of the Korean Data and Information Science Society
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• 제20권5호
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• pp.961-969
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• 2009

A hybrid censoring is a mixture of Type-I and Type-II censoring schemes. This paper deals with estimation based on Type-I hybrid censored samples from the half triangle distribution. We derive some estimators of the scale parameter of the half triangle distribution based on Type-I hybrid censored samples. We compare the proposed estimators in the sense of the mean squared error for various censored samples.

• Journal of the Korean Data and Information Science Society
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• 제19권3호
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• pp.951-957
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• 2008

We derive some approximate maximum likelihood estimators(AMLEs) and maximum likelihood estimator(MLE) of the scale parameter in the half-triangle distribution based on progressively Type-II censored samples. We compare the proposed estimators in the sense of the mean squared error for various censored samples. We also obtain the approximate maximum likelihood estimators of the reliability function using the proposed estimators. We compare the proposed estimators in the sense of the mean squared error.

• Journal of Information Processing Systems
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• 제13권4호
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• pp.818-833
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• 2017

This paper introduces a new algorithm that renders motion blur using triangular motion paths. A triangle occupies a set of pixels when moving from a position in the start of a frame to another position in the end of a frame. This is a motion path of a moving triangle. For a given pixel, we use a motion path of each moving triangle to find a range of time that this moving triangle is visible to the camera. Then, we sort visible time ranges in the depth-time dimensions and use bitwise operations to solve the occlusion problem. Thereafter, we compute an average color of each moving triangle based on its visible time range. Finally, we accumulate an average color of each moving triangle in the front-to-back order to produce the final pixel color. Thus, our algorithm performs shading after the visibility test and renders motion blur in real time.

• 한국컴퓨터그래픽스학회논문지
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• 제17권3호
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• pp.9-19
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• 2011

삼각형간의 교차 계산은 많은 3 차원 기하 문제들을 해결하는데 있어서 기본적으로 요구되는 연산 과정이다. 본 논문에서는 대량의 삼각형 집합 안에서의 교차 계산을 효율적이며 강인하게 처리할 수 있는 GPU 알고리즘을 제안한다. 이 알고리즘은 k-d 트리의 구성, 삼각형쌍 생성, 정확한 교차 계산을 모두 GPU에서 처리한다. 여기서 사용되는 k-d 트리에서는 분할 과정 중에 삼각형들의 복사가 많이 발생한다. 이렇게 복사된 삼각형들로 인하여 중복된 삼각형쌍들이 많이 생성되는데, 이러한 중복 삼각형쌍들을 효율적으로 제거하기 위하여 분할 인덱스를 도입하였다. 분할 인덱스는 간단한 논리곱 연산만으로 중복 여부를 효과적으로 판단할 수 있다. 수치적 강인성을 높이기 위하여는 부동소숫점 필터링을 통해 불안전한 삼각형쌍들을 분리하고, CLP(controlled linear perturbation)를 이용하여 CPU쓰레드에서 처리하도록 하였다. 제안한 알고리즘은 기존의 민코스키합 알고리즘의 합삼각형 교차계산에 적용하여 효율성과 강인성을 입증하였다.