• 한국자동차공학회논문집
• /
• 제16권5호
• /
• pp.128-133
• /
• 2008

In this paper, a new technique was suggested to estimate vehicle speed for the traffic accident reconstruction, and accident investigators can estimate initial vehicle speed based on this suggested technique. Turning tests with several vehicle speeds were executed and compared with the motion of the vehicle and the shape of the tire marks. A new method for estimating the coefficient of friction is suggested by using the longitudinal and lateral components of tire marks. And also, a speed calculation graph is suggested to estimate vehicle speed for traffic accident reconstruction.

• 한국해안해양공학회:학술대회논문집
• /
• 한국해안해양공학회 2008년도 발표논문집
• /
• pp.9-12
• /
• 2008

• 한국산업정보학회:학술대회논문집
• /
• 한국산업정보학회 1999년도 춘계학술대회 발표논문집
• /
• pp.205-209
• /
• 1999

일반화된 지수생존모형(generalized exponential survival model)을 고려하여 이 모형의 모수를 추정하는 수정된 FS(modified Fisher scoring)방법을 제안한다. 이를 위해 우도방정식(likelihood equation)을 유도하고 초기추정치 (initial estimate)를 포함한 추정알고리즘(estimating algorithm)을 개발한다.

• 한국해안해양공학회:학술대회논문집
• /
• 한국해안해양공학회 2008년도 발표 논문집 제17권
• /
• pp.9-12
• /
• 2008

• Communications for Statistical Applications and Methods
• /
• 제2권1호
• /
• pp.99-111
• /
• 1995

It is shown that the adaptive kernel methods can potentially produce superior density estimates to the fixed one. In using the adaptive estimates, problems pertain to the initial choice of the estimate can be solved by iteration. Also, simultaneous recommended for variety of distributions. Some data-based method for the choice of the parameters are suggested based on simulation study.

• 대한수학회지
• /
• 제60권3호
• /
• pp.619-634
• /
• 2023

This paper considers a parabolic-hyperbolic-hyperbolic type chemotaxis system in ℝ^d, d ≥ 3, describing tumor-induced angiogenesis. The global existence result and temporal decay estimate for a unique mild solution are established under the assumption that some Sobolev norms of initial data are sufficiently small.

• 한국안전학회지
• /
• 제30권5호
• /
• pp.131-137
• /
• 2015

For the evaluation of safety margin of a nuclear power plant using a conservative methodology, the influence of applied assumptions such as initial conditions and boundary conditions needs to be assessed deliberately. Usually, a combination of the most conservative initial conditions is determined, and the safety margin for the transient is evaluated through the analysis for this conservative conditions. In existing conservative methodologies, a most-conservative condition is searched through the analyses for the maximum, minimum, and nominal values of the major parameters. In the present study, we investigates a new approach which can be applied to choose a most-conservative initial condition effectively when a best-estimate computer code and a conservative evaluation methodology are utilized for the evaluation of safety margin of transients. By constituting the band of various initial conditions using the random sampling of input parameters, the sensitivity study for various parameters are performed systematically. A method of sampling the value of control or operation parameters for a certain range is adopted by use of MOSAIQUE program, which enables to minimize the efforts for achieving the steady-state for various different conditions. A representative control parameter is identified, which governs the reactor coolant flow rate, pressurizer pressure, pressurizer level, and steam generator level, respectively. It is shown that an appropriate distribution of input parameter is obtained by adjusting the range and distribution of the control parameter.

• Structural Engineering and Mechanics
• /
• 제29권5호
• /
• pp.469-488
• /
• 2008

Finite element methods have often been used for structural analyses of various mechanical problems. When finite element analyses are utilized to resolve mechanical systems, numerical uncertainties in the initial data such as structural parameters and loading conditions may result in uncertainties in the structural responses. Therefore the initial data have to be as accurate as possible in order to obtain reliable structural analysis results. The typical finite element method may not properly represent discrete systems when using uncertain data, since all input data of material properties and applied loads are defined by nominal values. An interval finite element analysis, which uses the interval arithmetic as introduced by Moore (1966) is proposed as a non-stochastic method in this study and serves a new numerical tool for evaluating the uncertainties of the initial data in structural analyses. According to this method, the element stiffness matrix includes interval terms of the lower and upper bounds of the structural parameters, and interval change functions are devised. Numerical uncertainties in the initial data are described as a tolerance error and tree graphs of uncertain data are constructed by numerical uncertainty combinations of each parameter. The structural responses calculated by all uncertainty cases can be easily estimated so that structural safety can be included in the design. Numerical applications of truss and frame structures demonstrate the efficiency of the present method with respect to numerical analyses of structural uncertainties.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2003년도 ICCAS
• /
• pp.990-994
• /
• 2003

When the low cost IMU is used, the result of the stationary self alignment is not suitable for navigation. In this paper, an in-motion alignment method is proposed to obtain an accurate initial attitude of a low cost IMU based GPS/INS integration system. To design Kalman filter for alignment, large heading error model is introduced. And then Kalman filter is designed to estimate initial attitude error as the indirect feedback filter. In order to assess performance of the alignment method, computer simulations are carried out. The simulation results show that initial attitude error rapidly reduces.

• 한국자동차공학회논문집
• /
• 제1권1호
• /
• pp.59-65
• /
• 1993

In a spark ignition engine, in order to make research on flame propagation, attentive concentration should be paid on initial combustion stage about the formation and development of flame. In addition, the initial stage of combustion governs overall combustion period in a spark ignition engine. With the increase of the size of flame kernel, it could reach initial flame stage easily, and the mixture could proceed to the combustion of stabilized state. Therefore, we must study the theoretical calculation of minimum flame kernel radius which effects on the formation and development of kernel. To calculate the minimum flame kernel radius, we must know the thermal conductivity, flame temperature, laminar burning velocity and etc. The thermal conductivity is derived from the molecular kinetic theory, the flame temperature from the chemical reaction equations and the laminar burning velocity from the D.K.Kuehl's formula. In order to estimate the correctness of the theoretically calculated minimum flame kernel radius, the researcheres compared it with the RMaly's experimental values.