• Title/Summary/Keyword: Parameter study

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A Development of Traffic Accident Models at 4-legged Signalized Intersections using Random Parameter : A Case of Busan Metropolitan City (Random Parameter를 이용한 4지 신호교차로에서의 교통사고 예측모형 개발 : 부산광역시를 대상으로)

  • Park, Minho;Lee, Dongmin;Yoon, Chunjoo;Kim, Young Rok
    • International Journal of Highway Engineering
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    • v.17 no.6
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    • pp.65-73
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    • 2015
  • PURPOSES : This study tries to develop the accident models of 4-legged signalized intersections in Busan Metropolitan city with random parameter in count model to understanding the factors mainly influencing on accident frequencies. METHODS : To develop the traffic accidents modeling, this study uses RP(random parameter) negative binomial model which enables to take account of heterogeneity in data. By using RP model, each intersection's specific geometry characteristics were considered. RESULTS : By comparing the both FP(fixed parameter) and RP modeling, it was confirmed the RP model has a little higher explanation power than the FP model. Out of 17 statistically significant variables, 4 variables including traffic volumes on minor roads, pedestrian crossing on major roads, and distance of pedestrian crossing on major/minor roads are derived as having random parameters. In addition, the marginal effect and elasticity of variables are analyzed to understand the variables'impact on the likelihood of accident occurrences. CONCLUSIONS : This study shows that the uses of RP is better fitted to the accident data since each observations'specific characteristics could be considered. Thus, the methods which could consider the heterogeneity of data is recommended to analyze the relationship between accidents and affecting factors(for example, traffic safety facilities or geometrics in signalized 4-legged intersections).

A study on numerical modeling method considering gap parameter and backfill grouting of the shield TBM tunnel (쉴드 TBM 터널의 gap parameter와 뒤채움재를 고려한 수치모델링 방법에 대한 연구)

  • You, Kwang-Ho;Kim, Young-Jin
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.5
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    • pp.799-812
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    • 2017
  • Backfill grouting and realistic convergence distribution were not properly considered in previous studies on 2D numerical analysis of a shield TBM tunnel. In this study, a modeling method was suggested to cope with this problem by considering a realistic convergence distribution and proper properties of backfill grouting. To this end, the influence of gap parameter and depth of rock cover on volume loss and composed of ground volume loss around tunnel excavation and surface volume loss were analyzed with a single layer of weathered soil. As a result, most of surface settlements were occurred immediately after excavation. Additional, as depth of rock cover and gap parameter increased, the influence range of surface settlement curves obtained from 2D numerical analyses became broader than a suggested theoretical equation. Therefore, it is inferred that gap parameter should be applied based on load distribution ratio and the property of backfill grouting properly considered for the estimation of the precise behavior of a shield TBM tunnel in 2D numerical analysis.

Calculation of $G_1$ for unidirectional laminated composites by using the two parameter technique (이항변수방법을 사용한 단일방향 적층복합재의 전단모드 에너지방출률 계산)

  • Rhee, Gyeong-Yeop
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.1
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    • pp.164-172
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    • 1997
  • Two parameter technique that uses far-field stress and displacement distributions was applied to composite laminates in order to calculate mode II energy release rate, $G_{II}$ . The $G_{II}$ calculated by two parameter technique was compared with that calculated from the crack closure method to inspect the effectiveness of two parameter technique. Sensitivity study of two parameter technique to the crack extension size was also performed. The results showed that both methods produced comparable $G_{II}$ results. In particular, it was found that although the crack closure method was affected by the crack extension size, the two parameter technique was less affected by the crack extension size.

Development of Fretting Fatigue Parameter (접촉피로 파라미터의 개발)

  • Lee, Hyuk-Jae
    • Journal of the Korea Institute of Military Science and Technology
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    • v.14 no.1
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    • pp.92-99
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    • 2011
  • In this study, new multi-axial, critical plane based, fretting fatigue crack initiation parameter is developed by the addition of a new term into the Modified Shear Stress Range(MSSR) parameter. The newly developed parameter (MSSR') is then used to evaluate fretting fatigue life of titanium alloy, Ti-6A1-4V with various contact conditions. Finite element analysis is also used in order to obtain stress distribution on the contact surface during fretting fatigue test, which is then used for the calculation of fretting fatigue parameter. The MSSR' parameter shows better performance in predicting fretting fatigue lives from the conventional fatigue data, and less scattering within fretting fatigue data with different contact geometries.

Parameter resetting in adult second language acquisition (성인의 제2 언어 습득에 있어서 매개변수 재고정)

  • Kim, Hak-Soo
    • English Language & Literature Teaching
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    • no.5
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    • pp.219-247
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    • 1999
  • The purpose of this paper is to examine how Korean learners of English reset the "prodrop" parameter of Korean into "non-prodrop" parameter of English in the process of English acquisition. An experiment was conducted to 45 Korean learners of English on the prodrop phenomenon, namely on the null referential or null nonreferential subject, and subject-verb agreement by way of grammatical judgment. The results of the experiment are as follows: First, L2 learners follow the parameter of L1, and then reset the parameter of L2 regardless of the parameter of L1 as their L2 abilities advance. Thus, this study provides further support for the hypothesis that universal grammar is available via L1. Second, the referential subject is, at first, easier to acquire than nonreferential subject, and the triggering fact for the switch from [+prodrop] to [-prodrop] was the use of nonreferential subjects. Third, 3rd person agreement has no connection with the acquisition of the prodrop parameter as a result of subject-verb agreement. Therefore, these results indicate that verb agreement is not a trigger for the recognition of the obligatory subject.

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Design and behavior of two profiles for structural performance of composite structure: A fluid interaction

  • Thobiani, Faisal Al;Hussain, Muzamal;Khadimallah, Mohamed Amine;Ghandourah, Emad;Alhawsawi, Abdulsalam;Alshoaibi, Adil
    • Steel and Composite Structures
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    • v.43 no.2
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    • pp.221-228
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    • 2022
  • Two-dimensional stagnation point slip flow of a Casson fluid impinging normally on a flat linearly shrinking surface is considered. The modeled PDEs are changed into nonlinear ODEs through appropriate nonlinear transformations.The flow is assumed to be steady and incompressible, with external magnetic field acting on it. Similarity transformation is utilized to investigate the behavior of many parameters for heat and velocity distributions using truncation approach.The influence of buoyancy parameter, slip parameter, shrinking parameter, Casson fluid parameter on the heat profile. The effect of the magnetic parameter on the streamwise velocity profile is also investigated.

Correlation Analysis between the Rheology Parameters of Concrete and the Rheological Parameters of Wet Sieving Mortar (콘크리트 레올로지 정수와 Wet Sieving 모르타르 레올로지 정수의 상관관계 분석)

  • Kim, In-Tae;Lee, Yu-Jeong;Han, Dong-Yeop
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.05a
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    • pp.103-104
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    • 2023
  • In this study, the correlation between the rheolog y parameter of fresh concrete and the rheology parameter of wet sieving mortar was analyzed for analyzing to possibility predicting the rheology parameter of fresh concrete. Through the experiment, the dynamic yield stress and plastic viscosity of concrete and wet sieving mortar show a direct proportional relationship, and the two data had a correlation. Therefore, it is thought that it is possible to predict the rheology parameter of fresh concrete through the rheology parameter of wet sieving mortar. However, in order to more accurately predict the rheology parameter of fresh concrete, it is need additional relationship analysis by collecting more rheology parameter data of fresh concrete and wet sieving mortar.

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An Estimation Algorithm for the Earth Parameter and Resistivity using Artificial Neural Network (신경회로망을 이용한 대지파라미터와 대지저항률 해석 알고리즘)

  • Ryu, Bo-Hyuk;Kim, Jung-Hoon
    • Proceedings of the KIEE Conference
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    • 2005.07a
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    • pp.563-565
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    • 2005
  • In this study, a algorithm to estimate Equivalent earth resistivity and Earth parameter using Artificial Neural Network(ANN) was proposed. Structures of the soil are grouped by using SOM algorithm before estimation. Earth parameter and Equivalent earth resistivity are obtained by using BP algorithm. The effectiveness of the proposed algorithm was verified. In the case study. afterwards, the algorithm proposed in this study will be used in more applications and gained more reliability.

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A Study on the Robust Controller in Independent Modal space for Parameter Errors (파라메타 오차에 강인한 독립모달공간 제어기법에 대한 연구)

  • 황재혁;김준수;박대성;박명호
    • Journal of KSNVE
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    • v.6 no.5
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    • pp.595-605
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    • 1996
  • If the control force designed on the basis of the mathematical model with parameter errors is applied to control the actual system, the closed-loop performance of the actual system will be degraded depending on the degree of the errors, In this study, the effect of parameter errors on the robustness of several natural controls has been analyzed and compared. Every asymptoic stability condition for the natural controls has been derived using Lyapunov approach, and the characteristics of the stability conditions has also been compared. The extent of deviation of the closed-loop performance from the designed one for the natural controls is derived using operator techniques, and evaluated by numerical method. It has been found that the optimal control, acceleration feedback control, and acceleration-position feedback control among the considered natural controls would be robust one with respect to the parameter errors.

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Estimation of the Heat Budget Parameter in the Atmospheric Boundary Layer considering the Characteristics of Soil Surface (지표면의 특성을 고려한 대기경계층내의 열수지 parameter 추정 -열수지 parameter를 이용한 중규모 순환의 수치예측-)

  • 이화운;정유근
    • Journal of Environmental Science International
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    • v.5 no.6
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    • pp.727-738
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    • 1996
  • An one dimensional atmosphere-canopy-soil interaction model is developed to estimate of the heat budget parameter in the atmospheric boundary layer. The canopy model is composed of the three balance equations of energy, temperature, moisture at ground surface and canopy layer with three independent variables of Tf(foliage temperature), Tg(ground temperature), and qg(ground specific humidity). The model was verilied by comparative study with OSUID(Oregon State University One Dimensional Model) proved in HAPEX-MOBILHY experiment. Also we applied this model in two dimensional land-sea breeze circulation. According to the results of this study, surface characteristics considering canopy acted importantly upon the simulation of meso-scale circulation. The factors which used in the numerical experiment are as follows ; the change for a sort of soil(sand and peat), the change for shielding factor, and the change for a kind of vegetation.

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