• 대한교통학회지
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• 제11권2호
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• pp.63-84
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• 1993

The main purpose of this paper is to develop a route guidance system which is a part of the intelligent vehicle-highway system and to apply to a real world in order to evaluate usefulness of the system. To this end, significant literature review works with regard to vehicle navigation and route guidance systems were conducted and have provided an important information about state-of-the-art systems developed and tested by the advanced countries. A geographic information system, called INTGIS, was used to find the shortest path in a given road network. Three scenarios to find minimum path were simulated and observed : 1) with-constraint on intersections and road segments, 2) without-constraint on intersections and road segments, and 3) via several stops from origin to destination. Based on a series of experiments, the results indicate that the route guidance system developed in this research is very useful to inform drivers on highway and arterial the traffic informations such as congestion and incident.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1995년도 춘계공동학술대회논문집; 전남대학교; 28-29 Apr. 1995
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• pp.603-616
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• 1995

Presented in this paper is an algorithm to obtain the intersections of a polyhedral surface composed of triangle facets with a series of parallel planes for extracting machining information from the surface. The change of the topology of the intersection curves is caused by characteristic points of the surface when sectioning the surface with parallel planes. The characteristic points are internal maximum, internal minimum, internal saddle, boundary maximum, boundary minimum, boundary max-saddle, and boundary min-saddle points. The starting points of the intersects are found efficiently and robustly using the characteristic points. The characteristic points as well as the intersection contours can be used to evaluate the machining information for process planning, and to generate NC tool path in CAD/CAM system.

• 대한수학회보
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• 제51권1호
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• pp.253-266
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• 2014

Commutative rings in which every prime ideal is an intersection of maximal ideals are called Hilbert (or Jacobson) rings. We propose to define classical Hilbert modules by the property that classical prime submodules are intersections of maximal submodules. It is shown that all co-semisimple modules as well as all Artinian modules are classical Hilbert modules. Also, every module over a zero-dimensional ring is classical Hilbert. Results illustrating connections amongst the notions of classical Hilbert module and Hilbert ring are also provided. Rings R over which all modules are classical Hilbert are characterized. Furthermore, we determine the Noetherian rings R for which all finitely generated R-modules are classical Hilbert.

• 대한교통학회지
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• 제1권1호
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• pp.10-27
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• 1983

In order to improve the traffic enviroments in the urban streets of Seoul, the computer controlled traffic signal system was installed on 45 intersections at 1980. Afterward, yearly expansion was done to the numbers of 132 intersections and 232 loop detectors. The problems of timing plans were discussed, mainly pedestrian crossing timing as well as the generations of split and offset. The broad urban streets more than 30m require long phasing time of pedestrians, even though the equivalent or correspondent traffic volume is rare. The configuration of computer system for traffic control was disscussed in terms of control strategy. An overview also given. The improvements were measured at every quater. The travel speed improved to 42%, delay time reduced to 41% and number of stops to 43% respectively.

• 한국정밀공학회지
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• 제26권1호
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• pp.63-70
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• 2009

Proposed in the paper is an algorithm to generate tool-path for sculptured surface machining. The proposed algorithm computes tool path by slicing offset triangular mesh, which is the CL-surface (Cutter Location surface). Since the offset triangular mesh includes invalid triangles and self-intersections, it is necessary to remove invalid portions. For the efficient removal of the invalid portions, we extended the sweep line algorithm. The extended sweep line algorithm removes invalid portions very efficiently, and it also considers various degeneracy cases including multiple intersections and overlaps. The proposed algorithm has been implemented and tested with various examples.

• 한국CDE학회논문집
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• 제3권2호
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• pp.113-120
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• 1998

Calculation of intersection points by two curves is fundamental to computer aided geometric design. Bezier clipping is one of the well-known curve intersection algorithms. However, this algorithm is only applicable to Bezier curve representation. Therefore, the NURBS curves that can represent free from curves and conics must be decomposed into constituent Bezier curves to find the intersections using Bezier clipping. And the respective pairs of decomposed Bezier curves are considered to find the intersection points so that the computational overhead increases very sharply. In this study, extended Bezier clipping which uses the linear precision of B-spline curve and Grevill's abscissa can find the intersection points of two NURBS curves without initial decomposition. Especially the extended algorithm is more efficient than Bezier clipping when the number of intersection points is small and the curves are composed of many Bezier curve segments.

• 한국CDE학회논문집
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• 제5권4호
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• pp.336-346
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• 2000

This paper presents a geometric method that can detect and compute all conic sections in the intersection of two tori. Conic sections contained in a torus must be circles. Thus, when two tori intersect in a conic section, the intersection curve must be a circle as well. Circles in a torus are classified into profile circles, cross-sectional circlet, and Yvone-Villarceau circles. Based on a geometric classification of these circles, we present a procedural method that can detect and construct all intersection circles between two tori. All computations can be carried out using simple geometric operations only: e.g., circle-circle intersections, circle-line intersections, vector additions, and inner products. Consequently, this simple structure makes our algorithm robust and efficient, which is an important advantage of our geometric approach over other conventional methods of surface intersection.

• 한국도로학회논문집
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• 제14권5호
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• pp.145-155
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• 2012

PURPOSES: This study proposes a novel method based on microscopic simulation models to evaluate bicycle passing ways in mixed traffic flow conditions at signalized intersections. METHODS: Both operational efficiency and safety are taken into consideration in the evaluation. A widely used performance measure, delay, is used for evaluating the operational efficiency. Regarding the safety evaluation, surrogate safety measures (SSM) to represent traffic conflicts and the level of crash severity, DeltaS and Max.DeltaV, are applied in the proposed method. RESULTS: Extensive simulations and statistical tests show that an integrated bike-box way is identified as the best in terms of operational efficiency and safety. CONCLUSIONS: The proposed method and outcomes of this study will be valuable for bicycle traffic operations and facility design.

• Journal of applied mathematics & informatics
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• 제38권3_4호
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• pp.311-334
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• 2020

The solution of the elliptic partial differential equation has interface singularity at the points which are either the intersections of interfaces or the intersections of interfaces with the boundary of the domain. The singularities that arises in the elliptic interface problems are very complex. In this article we propose an exponentially accurate nonconforming spectral element method for these problems based on [7, 18]. A geometric mesh is used in the neighbourhood of the singularities and the auxiliary map of the form z = ln ξ is introduced to remove the singularities. The method is essentially a least-squares method and the solution can be obtained by solving the normal equations using the preconditioned conjugate gradient method (PCGM) without computing the mass and stiffness matrices. Numerical examples are presented to show the exponential accuracy of the method.

• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.527-529
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• 2015

The control delays at signal intersections have proved the source of numerous vehicular and environmental complications. Control delays both directly and indirectly hinder time- and cost-effective driving by extending the duration of time spent on the road and exhausting excessive amounts of fuel. They furthermore cause traffic congestion, thereby raising overall emission levels. It is therefore imperative to reduce control delays in order to achieve time and fuel economy and reduce vehicle-related pollution. The following study accordingly uses genetic algorithms to optimize traffic signals in congested environments.