• Title/Summary/Keyword: geometric safety

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Datalog Information System을 이용한 도로선형설계 및 안전분석기법

  • 최재성
    • Journal of Korean Society of Transportation
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    • v.6 no.1
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    • pp.33-41
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    • 1988
  • The Wisconsin Department of Transportation currently has a Datalog Information System which facilitates the collection of geometric characteristics at every 0.01 mile high way section. The objectives of this study are to develop the plan and profile drawing of a highway section utilizing the Datalog Information system and to develop a methodology of investigating the safety aspects associated with the highway section being considered. For this purpose, two of the highway design elements, the minimum stoping sight distance as well as passing sight distance based on the AASHTO requirements, were applied in this study. A computer program was also developed to facilitate the data processing activity. The results from the computer program and from a manual analysis which adopted the identical methodology used in the computer program were in a good agreement. a few discrepancies between the two results were due to the data collection error and they were believed to be negligible. Using the computerized methodology developed in this study one does not need the plan and profile drawing to investigate the safety of a highway section, which appears to be an essential progress to the Computer Aided design and Draft in highway engineering field.

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A Study on Surface Integrity in Ground Layers (연삭 가공면의 표면성상에 관한 연구)

  • Kim, Gyung-Nyun;Cheong, Chae-Cheon;Cha, Il-Nam
    • Journal of the Korean Society for Precision Engineering
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    • v.8 no.4
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    • pp.64-75
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    • 1991
  • The design of structures of modern industry has developed to satisfy stringent service, realiability and safety. Up to now, geometric profile which means surface foughness and dimension accuracy is mainly treated in manufacturing process of work surface. But it is inevitable to evaluate changes of surface geometry as well as the nature of alterations in surface layers because surface of workpiece changes as a result of phase transformation, chemical changes, plastic deformation and stress changes. This paper is to present principal data for safety design by verifying the effect of grinding conditions and method in grinding layers and to explain the method of measuring surface integrity. In this paper, structural steel(SM20C) is used as a workpiece. Of integrity, surface roughness in view of surface texture is analyzed by frequency domain and residual stress, structures and defect of ground layers in view of surface metallurgy are investigated.

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Traffic Accident Models of 3-Legged Signalized Intersections in the Case of Cheongju (3지 신호교차로의 교통사고 발생모형 - 청주시를 사례로 -)

  • Park, Byung-Ho;Han, Sang-Uk;Kim, Tae-Young
    • Journal of the Korean Society of Safety
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    • v.24 no.2
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    • pp.94-99
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    • 2009
  • This study deals with the traffic accidents at the 3-legged signalized intersections in Cheongu. The goals are to analyze the geometric, traffic and operational conditions of intersections and to develop a various functional forms that predict the accidents. The models are developed through the correlation analysis, the multiple linear, the multiple nonlinear, Poisson and negative binomial regression analysis. In this study, two multiple linear, two multiple nonlinear and two negative binomial regression models were calibrated. These models were all analyzed to be statistically significant. All the models include 2 common variables(traffic volume and lane width) and model-specific variables. These variables are, therefore, evaluated to be critical to the accident reduction of Cheongju.

A Study on the Highway Ramp Section for Simulation of Commercial Vehicle ESC Assesment (상용 ESC 평가 시뮬레이션을 위한 국내 고속도로 진출입로 연구)

  • Lee, Hongguk;Park, Joongyoung;Chang, Kyungjin;Suh, Leejung;Yoo, Songmin
    • Journal of Auto-vehicle Safety Association
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    • v.6 no.2
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    • pp.23-28
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    • 2014
  • Commercial vehicle ESC assessment for curvature road was conducted. The previous study of ESC activation condition for losing controllability utilizing the test protocols of double lane change and sine with dwell method was conducted without considering the geometric complexity of roadway design. Since critical rollover accidents were frequently observed in the exit ramp zone, variety of curve, slope and bank have been added for analysis conditions. Detailed feature of the ramp including location, dimension and design characteristics have been analyzed from the typical trumpet type ramp design. Analyzing accident data from 2008, two specific ramps have been selected due to their complexity in design and severity in steering operation.

On-road Vehicle Tracking using Laser Scanner with Multiple Hypothesis Assumption

  • Ryu, Kyung-Jin;Park, Seong-Keun;Hwang, Jae-Pil;Kim, Eun-Tai;Park, Mignon
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.9 no.3
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    • pp.232-237
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    • 2009
  • Active safety vehicle devices are getting more attention recently. To prevent traffic accidents, the environment in front and even around the vehicle must be checked and monitored. In the present applications, mainly camera and radar based systems are used as sensing devices. Laser scanner, one of the sensing devices, has the advantage of obtaining accurate measurement of the distance and the geometric information about the objects in the field of view of the laser scanner. However, there is a problem that detecting object occluded by a foreground one is difficult. In this paper, criterions are proposed to manage this problem. Simulation is conducted by vehicle mounted the laser scanner and multiple-hypothesis algorithm tracks the candidate objects. We compare the running times as multi-hypothesis algorithm parameter varies.

Accident Analysis of 3-legged and 4-legged Roundabouts (3지와 4지 회전교차로의 사고분석)

  • Park, Min-Kyu;Park, Byung-Ho
    • Journal of the Korean Society of Safety
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    • v.27 no.3
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    • pp.161-166
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    • 2012
  • This study deals with the accident of roundabout. The objective is to analyze the traffic accidents occurred in 3-legged and 4-legged roundabouts through the developed models. In developing the multiple linear regression models, this study uses the number of traffic accidents as a dependent variable and such the variables as geometric structures, traffic characters and others as the independent variables. The correlation and multicollinearity of variables were analyzed using SPSS17.0. The main results are as follows. First, R-square value of developed models were analyzed to be 0.851(3-leg) and 0.689(4-leg), respectively. Second, the independent variables in the 3-legged roundabout accident model were analyzed to be the traffic volume and number of crosswalk, and the variables in the 4-legged roundabouts were evaluated to be the traffic volume and signal. Finally, the paired t-test shows that the predicted values and observed values are not statistically different.

Fatigue Characteristics of Non Load-Carrying Fillet Welded Joints According to Post-Processing (용접후처리에 따른 하중비전달형 필렛용접부의 피로특성)

  • Hong, Sung-Wook
    • Journal of the Korean Society of Safety
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    • v.25 no.6
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    • pp.161-168
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    • 2010
  • A series of fatigue tests have been performed on the non-load carrying fillet welded joints in order to quantitatively assess the fatigue characteristics due to the grindings and TIG(Tungsten Inert Gas) welding treatments. From the results of fatigue tests, it has been shown that the fatigue strengths at $2{\times}106$ load cycles were improved in the case of the grinding sand TIG welding treatments, and we could know that it is satisfying fatigue strength prescribed in fatigue design standard in general. Besides, from the results of fracture mechanics approaches, the geometric shape correction factors were the most dominant factors in the initial fatigue crack growth, but as the fatigue crack develops, the finite plate correction factor were became the most dominant factor, and the fatigue life on non-load carrying fillet welded joints could be relatively exactly estimated by using the relations between fatigue crack growth rate and stress intensity factor obtained from finite element analysis and existing proposed formulae.

Inelastic Buckling Analysis of Semi-rigid Frames with Shear Deformations by Haringx's Theories (Haringx의 전단변형 이론을 고려한 부분강절 뼈대구조의 비탄성 좌굴해석)

  • Min, Byoung-Cheol
    • Journal of the Korean Society of Safety
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    • v.29 no.3
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    • pp.64-71
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    • 2014
  • The generalized tangential stiffness matrix of semi-rigid frame element with shear deformations based on Haringx's shear theory is newly derived and compared with the previous study based on Engesser's shear theory. Also, linearized elastic and geometric stiffness matrices are newly presented from the exact tangential stiffness matrix. In oder to obtain the inelastic system buckling load of shear flexible semi-rigid frame structure, the Ef method by tangential modulus theory is adopted and the FE analysis programs are developed. Finally, the shear and semi-rigid effects of system bucking are investigated by two numerical examples.

A New Multivariate System Process Capability Index (다변량 시스템 공정능력지수(SCpsk))

  • 조남호;이용훈
    • Journal of the Korea Safety Management & Science
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    • v.5 no.3
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    • pp.145-156
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    • 2003
  • As we understand it, Process Capability indices are intended to provide single-number assessments of ability to meet specification limits on quality characteristics of interest. As a consequence of the varied ways in which PCIs are used, there have been two natural lines of research work: $\circled1$ studies on the properties of PCIs and their estimators in many different environments; $\circled2$ construction of new PCIs purporting to have better properties in certain circumstances. The most of existing process capability indices are concerned with the single variable. But, in many cases, a quality characteristic is composed with several factors. In that case, we want to know the integrated process capability of a quality characteristic not those of each factor. In this paper, we proposed a new multivariate system process capability index called $MSPCI:SC_{psk}$ which is the geometric mean of performance measure $C_{psk}$'S, and will be used as the criterion to assess multiple response process designs. Numerical illustration is done for $SC_{psk}$, $\overline{C_p}$(f), Cp, Cpk, Cpm, and Cpsk.

Evaluation of Running Stability of Tilting Trains in Conventional Curved Track (틸팅차량의 기존선 곡선부 주행안정성 평가)

  • 엄기영;엄주환;유영화;최정호
    • Journal of the Korean Society for Railway
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    • v.7 no.4
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    • pp.367-373
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    • 2004
  • The investigation of running stability of the train for curved track is necessary in view of preventing the train from derailment caused by unbalanced forces transferred from the wheel and guaranteeing moderate level of running safety in curve sections. This paper carried out an analysis of running stability of tilting trains in conventional line which the test operation of tilting trains under development are scheduled. For this purpose, the wheel load and lateral pressure to the rail are evaluated. The criteria for the calculated wheel load and derailment coefficient are compared to the design criteria for running stability. It is founded that the running stability of tilting trains for curved track is guaranteed to have sufficient safety and the train speed in curve is governed by the geometric layout of track rather than the criteria for running stability.