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Development of Optimal-Path Finding System(X-PATH) Using Search Space Reduction Technique Based on Expert System (전문가시스템을 이용한 최적경로 탐색시스템(X-PATH)의 개발)

  • 남궁성;노정현
    • Journal of Korean Society of Transportation
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    • v.14 no.1
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    • pp.51-67
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    • 1996
  • The optimal path-finding problem becomes complicated when multiple variables are simultaneously considered such as physical route length, degree of congestion, traffic capacity of intersections, number of intersections and lanes, and existence of free ways. Therefore, many researchers in various fields (management science, computer science, applied mathematics, production planning, satellite launching) attempted to solve the problem by ignoring many variables for problem simplification, by developing intelligent algorithms, or by developing high-speed hardware. In this research, an integration of expert system technique and case-based reasoning in high level with a conventional algorithms in lower level was attempted to develop an optimal path-finding system. Early application of experienced driver's knowledge and case data accumulated in case base drastically reduces number of possible combinations of optimal paths by generating promising alternatives and by eliminating non-profitable alternatives. Then, employment of a conventional optimization algorithm provides faster search mechanisms than other methods such as bidirectional algorithm and $A^*$ algorithm. The conclusion obtained from repeated laboratory experiments with real traffic data in Seoul metropolitan area shows that the integrated approach to finding optimal paths with consideration of various real world constraints provides reasonable solution in a faster way than others.

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Comparative Analysis of Technology Acceptance Model : Focusing on UTAUT1 and UTAUT2 (기술수용 모델의 비교분석 : UTAUT1과 UTAUT2를 중심으로)

  • Chung, Byoung-gyu
    • Journal of Venture Innovation
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    • v.1 no.2
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    • pp.109-121
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    • 2018
  • New technology had been introduced continually and in many cases, we approached technology persepectives when the new technology were introduced. It was very important that researching users acceptance of the new technology in the areas of marketing and strategy. Regarding to user accepatance of new technology, many research models had been exited. This study compared with 2 models which were proposed by Venkatesh et al. named UTAUT1, UTAUT2 based on the criteria which composed of application context, variables of model, the impacts of variables. The dominant matric which was applied in all functions and industries was not exited. For the purpose of improving predictability, single or compound matrics were useful according to industries and usage

An Experiment on Low NOx Combustion Characteristics in a Multi-Staged Burner (다단연소기를 이용한 저 NOx 연소특성 연구)

  • Cho, Eun-Seong;Sung, Yong-Jin;Chung, Suk-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.1
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    • pp.32-38
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    • 2003
  • Staged combustion, such as air- and fuel-staging, is a relatively well-known technique fur reduction of NOx emission and used in combination with other techniques nowadays. However, the design variables are still selected depending upon operating conditions. There are many variables tested to investigate the NOx emission characteristics fur changing of fuel or air velocity, swirl intensity, and staging ratio of air and fuel in multi-staged burner. In air-staging case, the fuel-rich condition of the primary combustion zone is very helpful to reduce NOx emission and its range is known to be restricted by the increase of carbon monoxide. However, in many cases carbon monoxide level is not too high to be restricted operating condition. So we tried to expand the equivalence ratio range to the richer condition in the primary combustion zone and certificate the function of each burner component and its contribution to the overall NOx production.

A study on the mapping between the feeding force of filter wire and welding position for the control of back bead shape in orbital TIG welding (원주 TIG 용접에서 이면 비드 형상 제어를 위한 Filter Wire 송급힘과 용접자세의 상관관계에 대한 연구)

  • 강선호;조형석;장희석;우승엽
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.792-795
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    • 1996
  • In TIG welding of pipe, back bead size monitoring is important for weld quality assurance. Many researches have been performed on estimation of the back bead size by heat conduction analysis. However numerical conduction model based on many uncertain thermal parameters causes remarkable errors and thermomechanical phenomena in molten pool can not be considered. In this paper, filler wire feeding force in addition to weld current, wire feedrate, torch travel speed and orbital position angle is monitored to estimate back bead size in orbital TIG welding. Monitored welding process variables are fed into an artificial neural network estimator which has been trained with the monitored process variables (input patterns) and actual back bead size (output patterns). Experimental verification of the proposed estimation method was performed. The predicted results are in a good agreement with the actual back bead shape. The results are quite promising in that estimation of invisible back bead shape can be achieved by analyzing the welding parameters without any conventional NDT of welds.

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A Study on the Development of a Real Time Simulator for the ESP (Electronic Stability Program) (전자식 차체 자세 제어 장치를 위한 실시간 시뮬레이터 개발에 관한 연구)

  • Kim, Tae Un;Cheon, Seyoung;Yang, Soon Young
    • Journal of Drive and Control
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    • v.16 no.4
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    • pp.48-55
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    • 2019
  • The Electronic Stability Program (ESP), a system that improves vehicle safety, also known as YMC (Yaw Motion Controller) or VDC (Vehicle Dynamics Control), is a system that operates in unstable or sudden driving and braking situations. Developing conditions such as unstable or sudden driving and braking situations in a vehicle are very dangerous unless you are an experienced professional driver. Additionally, many repetitive tests are required to collect reliable data, and there are many variables to consider such as changes in the weather, road surface, and tire condition. To overcome this problem, in this paper, hardware and control software such as the ESP controller, vehicle engine, ABS, and TCS module, composed of three control zones, are modeled using MATLAB/SIMULINK, and the vehicle, climate, and road surface. Various environmental variables such as the driving course were modeled and studied for the real-time ESP real-time simulator that can be repeatedly tested under the same conditions.

A Study on the Relationship between Impact Point of Vehicle and Throw Distance of Pedestrian (충격 지점과 보행자 전도 거리의 상관관계에 관한 연구)

  • Kang, Dae-Min;Ahn, Seung-Mo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.6 no.3
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    • pp.71-76
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    • 2007
  • The fatalities of pedestrian account for about 40.0% of all fatalities in Korea 2005. Vehicle-Pedestrian accident generates trajectory of pedestrian. In pedestrian involved accident, the most important data to inspect accident is throw distance of pedestrian. The throw distance of pedestrian can be influenced by many variables. The variables that influence trajectory of pedestrian can be classified into vehicular factors, pedestrian factors, and road factors. Vehicular factors are the frontal shape of vehicle, impact speed of vehicle, the offset of impact point. Many studies have been done about the relation between impact speed and throw distance of pedestrian. But the influence of the offset of impact point was neglected. The influence of the offset of impact point was analyzed by Working Model, and the trajectory of pedestrian, dynamic characteristics of multi-body were analyzed by PC-CRASH, a kinetic analysis program for a traffic accident. Based on the results, the increase of offset reduced the throw distance of pedestrian. However box type vehicle just like bus, the offset of impact point did not influence the throw distance of pedestrian considerably.

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Improved Response Surface Method Using Modified Selection Technique of Sampling Points (개선된 평가점 선정기법을 이용한 응답면기법)

  • 김상효;나성원;황학주
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1993.10a
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    • pp.248-255
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    • 1993
  • Recently, due to the increasing attention to the structural safety under uncertain environments, many researches on the structural reliability analysis have been peformed. Some useful methods are available to evaluate performance reliability of structures with explicit limit states. However, for large structures, in which structural behaviors can be analyzed with finite element models and the limit states are only expressed implicitly, Monte-Carlo simulation method has been mainly used. However, Monte-Carlo simulation method spends too much computational time on repetitive structural analysis. Many alternative methods are suggested to reduce the computational work required in Monte-Carlo simulation. Response surface method is widely used to improve the efficiency of structural reliability analysis. Response surface method is based on the concept of approximating simple polynomial function of basic random variables for the limit state which is not easily expressed in explicit forms of design random variables. The response surface method has simple algorithm. However, the accuracy of results highly depends on how properly the stochastic characteristics of the original limit state has been represented by approximated function, In this study, an improved response surface method is proposed in which the sampling points for creating response surface are modified to represent the failure surface more adequately and the combined use of a linear response surface function and Rackwitz-Fiessler method has been employed. The method is found to be more effective and efficient than previous response surface methods. In addition more consistent convergence is achieved, Accuracy of the proposed method has been investigated through example.

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A Study of the Relationship between Communication Patterns and Conflict between Old Parents and Adult Children (노부모와 성인자녀간의 의사소통 유형과 갈등에 관한 연구)

  • Shin, Il-Jin;Kim, Tae-Hyun
    • Journal of Families and Better Life
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    • v.9 no.1 s.17
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    • pp.27-44
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    • 1991
  • The purpose of this study is to investigate the relationship between communication pattern and conflict between old parents and their adult children. For this purose, 380 adult children are surveyed therefore the answers of survey are described by adult children only. The number of old parents turn to be 230 old fathers and 301 old mothers respectively, there numbers have included the case both parents are alive. The data were analysed several method with SPSS and the methods used for the analysis are Factor analysis, one way ANOVA, Scheffe-Test, Pearson's Correlation, Multple Regression. The results of this study are summarizd as follows ; 1) Old parents's communication patterns differ each other and under many variables. 2) In the conflicts between old parents and adult children differ each other and under many variables, too. 3) The relationship between communication patterens and conflict between old parent and adult children turn to be as follows : Two communication styles ie, the autoritarian style and insincere style increse conflicts. Frendly style have negatve affect to conflicts and decreses the conflicts. Sacrifice style is turn to have slightly affect the conflict.

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Estimation on the effect of design variables for sealing performance of the dust seal using finite element simulation (유한요소해석을 이용한 더스트 씰 밀봉성에 대한 설계변수의 영향평가)

  • Lee K.O.;Lee S.U.;Huh Y.M.;Kang S.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.123-124
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    • 2006
  • Usually, hydraulic cylinder is widely used as the actuator in the equipment of construction machines, airplane and military machines. In case of these devices, due to use under severe environment such as water, $SiO^2$ and dust, etc. seal which has high packing ability and long service life has been required. These characteristics are largely influenced by material and geometries of seal such as approach angle, withdrawal angle and interference. Recently, many a study about seal material has been performed so that many materials have been developed. But the concrete studies including the relationships between geometry of seal and sealing performance have hardly been performed yet. Therefore, in this study, we predicted the deformation behavior and contact normal distribution of dust seal with the variation of geometries of seal lip using finite element analysis. And based on the results of analyses, we discussed the effects of the design variables fur sealing performance of the dust seal.

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Design Automization for Torque Converter Damper Spring Using Optimization (최적화를 통한 토크 컨버터 댐퍼 스프링 설계 자동화에 관한 연구)

  • Park, Byoung-Keon;Hwang, Gil-Un;Kim, Jay-Jung;Jang, Jae-Deok
    • Korean Journal of Computational Design and Engineering
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    • v.12 no.3
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    • pp.163-170
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    • 2007
  • A torque converter, connected to a transmission/transaxle input shaft, connects, multiplies and interrupts the flow of engine torque into the transmission. Damper springs are usually equipped in a torque converter to convert stably the torque power supplied from engine. Damper Springs generally have the most flexible design variables among vehicle transmission parts, so that they could be effective design factors to improve the entire vehicle's performance. Damper spring, however, has geometric complexity after it equipped in a torque converter. For that reason, modeling a damper spring requires expert's knowledge to determine many design parameters and satisfy the functional requirements at the same time. In this paper, we introduce an optimum design method applied in detailed-design stage to reduce design process and financial loss caused by adequate design. Many design variables have to be classified and structuralized for Optimization. This also could make designer concentrate on functional requirements of damper spring, not on design possibility. In addition, modeling an assembled spring has technical restriction with primitives of the current major CAD solutions because of complexity of assembled spring shape. Thus, one of modeling solution presented in this paper since detailed and exact modeling is important for CAE or DMU.