• Title/Summary/Keyword: intersection design

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A Study on the Minimization of Cutting Slope around Tunnel Portal (지형과 사교하는 갱구부의 비탈면 최소화 방안 연구)

  • Jeong Kwan Sik;Park Ji Hoon;Kim Gun Ho;Lee Wan Jae
    • 한국터널공학회:학술대회논문집
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    • 2005.04a
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    • pp.359-371
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    • 2005
  • The Cutting slope is to be minimized when a tunnel meets the contour of slope terrain at a right angle around its portal. However, a tunnel portal has been generally installed at a right angle to the longitudinal axis of a tunnel with no consideration of the intersection angle with the slope terrain. This sometimes tended to cause huge cutting slope that resulted in many disadvantage in terms of safty, economy and environment. Therefore, the minimization of cutting slope is studied by taking the intersection angle into account, and the result is compared with that by the conventional method. In addition a design method for the inclined portal to the tunnel axis is proposed through 3D-FEM analysis, also the applicable ground condition is suggested.

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Techniques of Automatic Finite Element Mesh Generation on Surface Primitives (원시곡면 위의 유한요소망 자동생성 기법)

  • 이재영
    • Korean Journal of Computational Design and Engineering
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    • v.1 no.3
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    • pp.189-202
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    • 1996
  • Complex geometric shapes can be defined simply and efficiently by combining and operating various surface primitives. These primitives and their intersection curves are used in finite element mesh generation to form an easy and intuitive procedure for finite element modelling of curved surfaces. This paper proposes techniques of automatic mesh generation on surface primitives with arbitrarily shaped boundaries and control curves, which may be created by surface to surface intersection. A method of automatic mesh generation on plane, which was previously developed by the author, has been modified for application to the surface mesh generation. Owing to the mesh generation-wise differences between planes and surfaces, the surfaces should be transformed into conceptual plane so that the modified plane mesh generation method can be applied. Surface development, mapping and mesh reconstruction are the key techniques suggested in this paper. The selection of the technique to apply can be determined automatically on the basis of the developability, existence of singularity and other characteristics of the surfaces on which the mesh is to be generated. The suggested techniques were implemented into parts of mesh generation functions of the finite element software, MacTran. Their validity and practicality were manifested by the actual use of this software.

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A Study on Automatic Modeling of Pipelines Connection Using Point Cloud (포인트 클라우드를 이용한 파이프라인 연결 자동 모델링에 관한 연구)

  • Lee, Jae Won;Patil, Ashok Kumar;Holi, Pavitra;Chai, Young Ho
    • Korean Journal of Computational Design and Engineering
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    • v.21 no.3
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    • pp.341-352
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    • 2016
  • Manual 3D pipeline modeling from LiDAR scanned point cloud data is laborious and time-consuming process. This paper presents a method to extract the pipe, elbow and branch information which is essential to the automatic modeling of the pipeline connection. The pipe geometry is estimated from the point cloud data through the Hough transform and the elbow position is calculated by the medial axis intersection for assembling the nearest pair of pipes. The branch is also created for a pair of pipe segments by estimating the virtual points on one pipe segment and checking for any feasible intersection with the other pipe's endpoint within the pre-defined range of distance. As a result of the automatic modeling, a complete 3D pipeline model is generated by connecting the extracted information of pipes, elbows and branches.

Reduction of Cogging Torque in BLDC Motors (BLDC 전동기의 코깅 토오크 저감설계)

  • Kim, Suk-Ki;Chung, Tae-Kyung
    • Proceedings of the KIEE Conference
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    • 1995.07a
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    • pp.83-85
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    • 1995
  • In a permanent magnet motor, cogging torque arises from the intersection of the rotor magnets with the steel teeth on the stator. This paper describes design measures which can be taken to reduce the cogging torque. In this paper for the optimal shape design of brushless DC motor, evolution strategy is investigated to find the dimension of stator of BLDC motor that minimizes the cogging torque. The corresponding field analysis is performed by two-dimensional finite element method.

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DEVELOPMENT OF SAFETY-BASED LEVEL-OF-SERVICE CRITERIA FOR ISOLATED SIGNALIZED INTERSECTIONS (독립신호 교차로에서의 교통안전을 위한 서비스수준 결정방법의 개발)

  • Dr. Tae-Jun Ha
    • Proceedings of the KOR-KST Conference
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    • 1995.02a
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    • pp.3-32
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    • 1995
  • The Highway Capacity Manual specifies procedures for evaluating intersection performance in terms of delay per vehicle. What is lacking in the current methodology is a comparable quantitative procedure for ass~ssing the safety-based level of service provided to motorists. The objective of the research described herein was to develop a computational procedure for evaluating the safety-based level of service of signalized intersections based on the relative hazard of alternative intersection designs and signal timing plans. Conflict opportunity models were developed for those crossing, diverging, and stopping maneuvers which are associated with left-turn and rear-end accidents. Safety¬based level-of-service criteria were then developed based on the distribution of conflict opportunities computed from the developed models. A case study evaluation of the level of service analysis methodology revealed that the developed safety-based criteria were not as sensitive to changes in prevailing traffic, roadway, and signal timing conditions as the traditional delay-based measure. However, the methodology did permit a quantitative assessment of the trade-off between delay reduction and safety improvement. The Highway Capacity Manual (HCM) specifies procedures for evaluating intersection performance in terms of a wide variety of prevailing conditions such as traffic composition, intersection geometry, traffic volumes, and signal timing (1). At the present time, however, performance is only measured in terms of delay per vehicle. This is a parameter which is widely accepted as a meaningful and useful indicator of the efficiency with which an intersection is serving traffic needs. What is lacking in the current methodology is a comparable quantitative procedure for assessing the safety-based level of service provided to motorists. For example, it is well¬known that the change from permissive to protected left-turn phasing can reduce left-turn accident frequency. However, the HCM only permits a quantitative assessment of the impact of this alternative phasing arrangement on vehicle delay. It is left to the engineer or planner to subjectively judge the level of safety benefits, and to evaluate the trade-off between the efficiency and safety consequences of the alternative phasing plans. Numerous examples of other geometric design and signal timing improvements could also be given. At present, the principal methods available to the practitioner for evaluating the relative safety at signalized intersections are: a) the application of engineering judgement, b) accident analyses, and c) traffic conflicts analysis. Reliance on engineering judgement has obvious limitations, especially when placed in the context of the elaborate HCM procedures for calculating delay. Accident analyses generally require some type of before-after comparison, either for the case study intersection or for a large set of similar intersections. In e.ither situation, there are problems associated with compensating for regression-to-the-mean phenomena (2), as well as obtaining an adequate sample size. Research has also pointed to potential bias caused by the way in which exposure to accidents is measured (3, 4). Because of the problems associated with traditional accident analyses, some have promoted the use of tqe traffic conflicts technique (5). However, this procedure also has shortcomings in that it.requires extensive field data collection and trained observers to identify the different types of conflicts occurring in the field. The objective of the research described herein was to develop a computational procedure for evaluating the safety-based level of service of signalized intersections that would be compatible and consistent with that presently found in the HCM for evaluating efficiency-based level of service as measured by delay per vehicle (6). The intent was not to develop a new set of accident prediction models, but to design a methodology to quantitatively predict the relative hazard of alternative intersection designs and signal timing plans.

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A Tall Building Ethos of Integration

  • Lee, Brian
    • International Journal of High-Rise Buildings
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    • v.7 no.1
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    • pp.47-64
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    • 2018
  • The last decade has seen great design opportunities for tall building construction around the globe. The best designs represent a new generation of skyscrapers that go beyond willful preconceptions of building form and iconography, trying instead to simultaneously address interrelated issues of program space utility, structural efficiency, and environmentally sustainable systems. The resulting identities of these towers are unique because of their search for the intersection of spaces tuned to people's needs, expressive optimized structures, and high performance, site-responsive systems. This paper, through examples of recent SOM towers, both built and unbuilt, will discuss how a design becomes content-driven, how ideas create value, and how the typology of the tall building is advanced through the integration of architecture design and engineering systems.

A Study on the Modern Fashion Design Applying Light and Rays -Focused on Italian Futurism and Russian Rayonism -

  • Park, Yoon-Jeong;Yang, Sook-Hee
    • The International Journal of Costume Culture
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    • v.3 no.3
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    • pp.212-222
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    • 2000
  • This study intends to observe how the essential elements of art have changed Human's sense of beauty extending over the whole lives as well as fashion through the investigation of Light and Rays which have played a important role in giving birthe to the new trend of art within the upheaval age of various cultures. The peculiarities of which Futurism of Italy and Rayonism of Russia including Impressionism have a great role in giving birth to a new trend of art by means of the development of science technology are like these. Impressionists looked for the origin of the subtle harmony in nature within changes of sun-rays. The special feature of Impressionism paintings was to express the line of vision diversely according to changes of light rather than to focus on the line of vision with clear outlines. Henceforth, Neo-Impressionism which developed Impressionism more systematically leaded changes of Light and Rays more systematically and scientifically and maintained Divisionnisme techniques which extends to lead towards color and light through dividing and juxtaposing color. In the early 20th century Futurists tried to express dynamism through the interpenetration of light and revive color and light through the division techniques of color and persist an artificial light like eletricity rather than a natural light. Rayonism of Russia which was ifluenced from Impressionism and Futurism maintained intersection of reflecting rays which emerges from an object of things more deeply. This pursuit of light and rays also light and rays also appears as it is in modern fashion. First, it is the fashion which applied sun-rays persisted by Impressionists and expressed colors which show differently according to direction of light. Second, it is the fashion design which re-analyzed what Futurists expressed artificial light and rays. Third, it is the design which expressed Divisionnisme theory persisted by Impressionists and Futurists into fashion as it is and was made of being divided the form of glittering light into small dots. Fourth, it is the fashion design which applied Rayonists'work which applied intersection of reflected rays. Like this, it is aproved that the pursuit of light and rays expresses as it is in modern fashion of the 21st.

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Balancer design for scroll compressors using vibration plane model (진동평면모델을 이용한 스크롤 압축기 균형추 설계)

  • Suh, Jeong-Hwan;Lee, Dong-Soo;Kim, Seung-Yup;Joh, Nam-Gyu;Lee, Hyung-Gook
    • 유체기계공업학회:학술대회논문집
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    • 2004.12a
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    • pp.527-532
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    • 2004
  • An effective balancing method for mil compressors is developed based on vibration plane model. By assuming the design range of balancer size is not large and considering only the radial axial direction rigid vibration of the mil compressors, we can find the vibration plane (V-plane) describing the vibration level of the scroll compressor depending upon balancer design specifications. By in the intersection of two minimum lines (areas) obtained from the couple of V-Planes we can find the design lesion to minimize vibration level of the compressor. The full design process is described by using an illustrative example with upper and lower balancer weights. Further more sensitivity analysis of parameters important for designation of size and positioning of the balancer is analyzed.

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Hysteretic behaviour of circular tubular T-joints with local chord reinforcement

  • Shao, Y.B.;Wang, Y.M.;Yang, D.P.
    • Steel and Composite Structures
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    • v.21 no.5
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    • pp.1017-1029
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    • 2016
  • When a welded circular hollow section (CHS) tubular joint is subjected to brace axial loading, failure position is located usually at the weld toe on the chord surface due to the weak flexural stiffness of the thin-walled chord. The failure mode is local yielding or buckling in most cases for a tubular joint subjected to axial load at the brace end. Especially when a cyclic axial load is applied, fracture failure at the weld toe may occur because both high stress concentration and welding residual stress along the brace/chord intersection cause the material in this region to become brittle. To improve the ductility as well as to increase the static strength, a tubular joint can be reinforced by increasing the chord thickness locally near the brace/chord intersection. Both experimental investigation and finite element analysis have been carried out to study the hysteretic behaviour of the reinforced tubular joint. In the experimental study, the hysteretic performance of two full-scale circular tubular T-joints subjected to cyclic load in the axial direction of the brace was investigated. The two specimens include a reinforced specimen by increasing the wall thickness of the chord locally at the brace/chord intersection and a corresponding un-reinforced specimen. The hysteretic loops are obtained from the measured load-displacement curves. Based on the hysteretic curves, it is found that the reinforced specimen is more ductile than the un-reinforced one because no fracture failure is observed after experiencing similar loading cycles. The area enclosed by the hysteretic curves of the reinforced specimen is much bigger, which shows that more energy can be dissipated by the reinforced specimen to indicate the advantage of the reinforcing method in resisting seismic action. Additionally, finite element analysis is carried out to study the effect of the thickness and the length of the reinforced chord segment on the hysteretic behaviour of CHS tubular T-joints. The optimized reinforcing method is recommended for design purposes.

Analysis of Dilemma Zone Safety Considering Signal Location (신호기 위치에 따른 딜레마존 안전율 분석)

  • Ryu, Chang-Nam;Kim, Won-Chul;Jang, Tae-Youn;Lim, Sam-Jin
    • Journal of Korean Society of Transportation
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    • v.26 no.1
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    • pp.7-14
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    • 2008
  • One of purposes of installing signals at intersections is to protect traffic conflicts and accidents from occurring by means of arranging the right-of-way of travel more clearly. On the other hand, the installation of signals, and especially their location, can also have negative effects on safety. Therefore, the location of signals is of great importance. To secure a high safety level for urban signalized intersection, efforts are required to introduce a comprehensive recommendation or guideline for safety aspects of signal installation that takes local conditions into account. In this context, this reports on a study that analyzed the influence of signal location on the behavior of drivers who approach a signalized intersection in urban area. As a result, the study found out that the traffic signal location strongly affects the braking point of the Dilemma Zone(DZ), and the braking point of the DZ based on driving speed. Also, in terms of design layout, it has been illustrated that there is a close relation between signal location and road safety, especially DZ safety. Finally, this paper proposes a practical recommendation for signal installation related to how to locate the signal in practice for the sake of securing the safety level of signalized intersection.