• 품질경영학회지
• /
• 제34권2호
• /
• pp.122-128
• /
• 2006

One feature of a computer simulation experiment, different from a physical experiment, is that the output is often deterministic. Moreover the codes are computationally very expensive to run. This paper deals with the design and analysis of computer experiments(DACE) which is a relatively new statistical research area. We model the response of computer experiments as the realization of a stochastic process. This approach is basically the same as using a spatial linear model. Applications to the optimal mechanical designing and model calibration problems are illustrated. Algorithms for selecting the best spatial linear model are also proposed.

• 한국공작기계학회논문집
• /
• 제13권6호
• /
• pp.107-113
• /
• 2004

This paper presents the pillar section optimization technique considering the reliability of the vehicle body structure consisted of complicated thin-walled panels. The response surface method is utilized to obtain the response surface models that describe the approximate performance functions representing the system characteristics on the section properties of the pillar and on the mass and the natural frequencies of the vehicle B.I.W. The reliability-based design optimization on the pillar sections Is performed and compared with the conventional deterministic optimization. The FORM is applied for the reliability analysis of the vehicle body structure. The developed optimization system is applied to the pillar section design considering the fundamental natural frequencies of passenger car body structure. By applying the proposed RBDO technique, it can be possible to optimize the pillar sections considering the reliability that engineers require.

• Nuclear Engineering and Technology
• /
• 제52권2호
• /
• pp.448-455
• /
• 2020

The H.B. Robinson Unit 2 (HBR-2) pressure vessel dosimetry benchmark is an in- and ex-Reactor Pressure Vessel (RPV) neutron dosimetry benchmark based on experimental data from the HBR-2 reactor, a 2300-MW PWR designed by Westinghouse and put in operation in March 1971, openly available through the SINBAD Database at OECD/NEA data Bank. The goals of the present work were to carry out three-dimensional (3D) fixed source transport calculations in both Cartesian (X,Y,Z) and cylindrical (R,θ,Z) geometries by using the TORT-3.2 discrete ordinates code on very detailed 3D HBR-2 geometrical models and to test the latest broad-group coupled (47 neutron groups + 20 photon groups) working cross section libraries in FIDO-ANISN format with same structure as BUGLE-96, such as BUGJEFF311.BOLIB, BUGENDF70.BOLIB and BUGLE-B7. The results obtained with all the cited libraries were satisfactory and are here reported and compared.

• 한국안전학회지
• /
• 제13권1호
• /
• pp.70-76
• /
• 1998

The smoke filling process for the atrium space containing a fire source is simulated using two types of deterministic fire models : Zone model and Field model. The zone model used is the CFAST(version 1.6) model developed at the Building and Fire Research Laboratories, NIST in the USA. The field model is a self-developed fire field model based on Computational Fluid Dynamics(CFD) theories. This article is focused on finding out the smoke movement and temperature distribution in atrium space which is cubic in shape. A computational procedure for predicting velocity and temperature distribution in fire-induced flow is based on the solution, in finite volume method and non-staggered grid system, of 3-dimensional equations for the conservation of mass, momentum, energy, species and so forth. The fire model i. e. Zone model and Field model predicted similar results for the clear height and the smoke layer temperature.

• 경영과학
• /
• 제19권1호
• /
• pp.13-28
• /
• 2002

This Paper discusses how to estimate the container yard space of a port container terminal as well as how much the Inventory level of containers Is affected by related factors such as allowable dwell time for containers, handling volume per containership, and loading/unloading productivity of a port container terminal. Under the assumption of static relations among the factors, a model for estimating the container yard space is suggested. In terms of arrival patterns of containers, sub-models for export, import, and transshipment containers are constructed separately. A numerical example and the sensitivity analysis for some parameters are provided to help intuitive understanding the characteristics of the suggested model. The experimental results show that the allowable dwell time for containers is the most critical one of the factors to influence on the maximum Inventory level of containers.

• Journal of Information Processing Systems
• /
• 제10권3호
• /
• pp.412-428
• /
• 2014

Request oriented sensor networks have stricter requirements than conventional event-driven or periodic report models. Therefore, in this paper we propose a minimum energy data aggregation (MEDA), which meets the requirements for request oriented sensor networks by exploiting a low power real-time scheduler, on-demand time synchronization, variable response frame structure, and adaptive retransmission. In addition we introduce a test bed consisting of a number of MEDA prototypes, which support near real-time bidirectional sensor networks. The experimental results also demonstrate that the MEDA guarantees deterministic aggregation time, enables minimum energy operation, and provides a reliable data aggregation service.

• Journal of Communications and Networks
• /
• 제16권5호
• /
• pp.534-547
• /
• 2014

Large-scale failures resulting from natural disasters or intentional attacks are now causing serious concerns for communication network infrastructure, as the impact of large-scale network connection disruptions may cause significant costs for service providers and subscribers. In this paper, we propose a new framework for the analysis and prevention of network service disruptions in large-scale failure scenarios. We build dynamic deterministic and probabilistic models to capture the impact of regional failures as they evolve with time. A probabilistic failure model is proposed based on wave energy behaviour. Then, we develop a novel approach for preventive protection of the network in such probabilistic large-scale failure scenarios. We show that our method significantly improves uninterrupted delivery of data in the network and reduces service disruption times in large-scale regional failure scenarios.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 하계학술대회 논문집 B
• /
• pp.623-625
• /
• 1998

This paper focuses on the fast convergence in nonlinear parameter optimization which is necessary for the fitting of nonlinear models to data. The simulated annealing(SA) and genetic algorithm(GA), which are widely used for combinatorial optimization problems, are stochastic strategy for search of the ground state and a powerful tool for optimization. However, their main disadvantage is the long convergence time by unnecessary extra works. It is also recognised that gradient-based nonlinear programing techniques would typically fail to find global minimum. Therefore, this paper develops a modified SA which is the SDS(Stochastic deterministic stochastic) algorithm can minimize cost function of optimal problem.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.795-800
• /
• 2009

Railway safety is one aspect of the transport service quality delivered to passengers, employees and third parties. To improve safety by a cultural shift from a deterministic to a risk based approach, European Railway Agency (ERA) introduces common and transparent methods to monitor safety performance and set targets and establishes safety management systems. The objective of this study is to review the common safety performance management method of the ERA(European Railway Agency) for it's application to the Korea railway. For this end, the risk assessment models were developed based on the accident scenarios and domestic railway accidents had been investigated and quantitative and qualitative analyses was performed using the developed information system.

• 전산구조공학
• /
• 제5권2호
• /
• pp.93-104
• /
• 1992

최적화기법의 최종목표는 전체최적점(golbal optimum point)을 정확히 그리고 효율적으로 구하는 것이다. 이를 위해 확률론적인 탐색과정을 가지는 Simulated Annealing과 Genetic Algorithm에 의한 최적화과정을 살펴보고, 수학적함수와 트러스, 보 구조물에 대해 최적설계를 행하여 전체최적점에 도달한 신뢰도 및 계산시간을 기준으로 기존의 확정론적 최적화기법에 의한 결과와 그 유용성을 비교검토하였다.