• Smart Structures and Systems
• /
• 제26권2호
• /
• pp.175-184
• /
• 2020

Conventional Monte Carlo simulation-based methods for seismic risk assessment of water networks often require excessive computational time costs due to the hydraulic analysis. In this study, an Artificial Neural Network-based surrogate model was proposed to efficiently evaluate the flow-based system reliability of water distribution networks. The surrogate model was constructed with appropriate training parameters through trial-and-error procedures. Furthermore, a deep neural network with hidden layers and neurons was composed for the high-dimensional network. For network training, the input of the neural network was defined as the damage states of the k-dimensional network facilities, and the output was defined as the network system performance. To generate training data, random sampling was performed between earthquake magnitudes of 5.0 and 7.5, and hydraulic analyses were conducted to evaluate network performance. For a hydraulic simulation, EPANET-based MATLAB code was developed, and a pressure-driven analysis approach was adopted to represent an unsteady-state network. To demonstrate the constructed surrogate model, the actual water distribution network of A-city, South Korea, was adopted, and the network map was reconstructed from the geographic information system data. The surrogate model was able to predict network performance within a 3% relative error at trained epicenters in drastically reduced time. In addition, the accuracy of the surrogate model was estimated to within 3% relative error (5% for network performance lower than 0.2) at different epicenters to verify the robustness of the epicenter location. Therefore, it is concluded that ANN-based surrogate model can be utilized as an alternative model for efficient seismic risk assessment to within 5% of relative error.

• 한국주거학회:학술대회논문집
• /
• 한국주거학회 2006년도 추계학술발표대회 논문집
• /
• pp.196-201
• /
• 2006

Existing model houses have played an important role in allow the customers to choose apartment. As the information technology has been advanced (e.g. a high-speed internet available in unit), customers' personality and preference to the design of apartment and the purchasing pattern have been changed. Construction firms have introduced VR(Virtual Reality) model house (e.g. Quick Time Virtual Reality) to meet the customers' expectation and need. The reality-based QTVR model house does not provide enough quality to satisfy the customers' expectation. To complement the shortcoming of the QTVR model house, this study presents a web-based cyber model house developed by using Turntool and Javascript. The cyber model house allows to communicate between supplier and customer over the internet.

• 한국자동차공학회논문집
• /
• 제18권3호
• /
• pp.26-36
• /
• 2010

This paper provides a description of the combustion model to obtain an accurate dynamic engine phenomena that satisfies real-time simulation for model-based engine control. The combustion chamber is modeled as a storage device for mass and energy. The combustion process is modeled in terms of a two-zone model for the burned and unburned gas fractions. The mass fraction burnt is modeled in terms of a Wiebe function. The instantaneous net engine torque is calculated from the engine speed and the instantaneous piston work. The modeling accuracy has been tested with a cylinder pressure data on a test bench and also the ability of real-time simulation has been checked. The results show that combustion model yields sufficiently good performance for the model-based control logic design. However the influence factors effected on model accuracy are some room for improvement.

• Journal of the Korean Data and Information Science Society
• /
• 제16권4호
• /
• pp.1147-1157
• /
• 2005

Bonus-Malus system is generally constructed based on claim frequency and Bayesian credibility model is used to represent claim frequency distribution. However, there is a problem with traditionally used credibility model for the purpose of constructing bonus-malus system. In traditional Bonus-Malus system adopted credibility model, individual estimates of premium rates for insureds are determined based solely on the total number of claim frequency without considering when those claims occurred. In this paper, a new model which is a modification of structural time series model applicable to counting time series data are suggested. Based on the suggested model relatively higher premium rates are charged to insured with more claim records.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 춘계학술대회
• /
• pp.1029-1034
• /
• 2004

Recent engineering process requires fast development and manufacturing of the products. This paper mainly discusses the process of rapid product development (RPD) from the reverse engineering to the optimal design. A laser scanning system scans a product and the efficient data processing method reduces the scanned point data. The reduced (scanned) points model is transformed to a finite element model without the construction of a CAD model. Since CAD modeling is a time-consuming work, skipping this step can save much time. This FE model is updated from the result based on the structural characteristics from modal test of the real model. For FE model updating, Response Surface Method is adopted. Finally, the updated FE model is optimized using the reliability-based topology optimization, which is developed recently. All these processes are applied to the design of an upper part model of a cellular phone.

• 정보교육학회논문지
• /
• 제6권2호
• /
• pp.187-200
• /
• 2002

본 연구에서는 인터넷 기반의 문제 해결 학습에서 교수자와 학습자가 겪게 되는 교수 학습의 어려운 점에 기초하여 인터넷 기반의 문제 해결 학습 모형을 개발하였다. 이를 위해 먼저 ICT-EUS[8]를 필요한 단계에 적용하는 7단계 문제 해결 모형을 제안하였다. 다음으로 7단계 문제 해결 모형을 반영한 인터넷 기반 문제 해결 학습 모형을 개발하였고, 모형의 수업 적용을 위한 지원시스템의 개요와 특징을 살펴보았다. 교수 학습 모형은 (1) 설계 (2) 준비 (3)교수 학습 실행 (4) 관리의 네 단계로 구성되어 있고 ICT-EUS 기반의 7단계 문제 해결 모형을 교수 학습 실행의 핵심 단계로 설정하였다. 본 연구에서 제안하는 7단계 문제 해결 모형, 인터넷 기반 문제 해결 학습 모형은 각 교과별 ICT 활용 학습에 구체적으로 적용할 수 있는 기능적 성격보다는 모든 교과에서 보편적으로 활용할 수 있는 범용성을 추구한다.

• 지능정보연구
• /
• 제6권1호
• /
• pp.35-50
• /
• 2000

Diverse requirements of users on web-based model management force a system agent to develop user-adaptive building a model in reality and providing an adequate solution method of the model. The relationship between models is important knowledge for the agent to effectively build a new model to adaptively adjust an existing model under a problem and to efficiently connect the new model into an adequate solution method. Since the generating process of the inter-model relationship is more difficult than the building a new model however the process mostly depends on the knowledge of operation research experts. Without the adequate scheme of the inter-model relationship the burden of the management for the agent increases rapidly and the quality of the services may worsen. This study shows that meta-knowledge generated from relationship between models is important for the user to build a model in reality and to acquire the solver appropriate to the model. The relationship that consists of common and exclusive objects between models can be represented by frames. The system under development to implement the idea includes user-adaptive ability which identifies a model through forward chaining method and searches the solver appropriate to the model by using the meta knowledge. We illustrate the meta knowledge with an applied delivery system in supply chain management.

• Journal of information and communication convergence engineering
• /
• 제9권6호
• /
• pp.666-670
• /
• 2011

In this paper, we propose a stable active contour based tracking method which utilizes the bimodal segmentation technique to obtain a background color diminished image frame. The proposed method overcomes the drawback of the Mansouri model which is liable to fall into a local minimum state when colors appear in the background that are similar to the target colors. The Mansouri model has been a foundation for active contour based tracking methods, since it is derived from a probability based interpretation. By stabilizing the model with the proposed speed function, the proposed model opens the way to extend probability based active contour tracking for practical applications.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
• /
• pp.211-218
• /
• 2002

An entity-based integrated design product and process model uses product and process entities to describe design information and design activities, respectively. The concepts and notation for product and process entities in the entity-based integrated design model are similar to the concepts of object-oriented programming languages such as C++ and Smalltalk. This paper uses C++ to program an entity-based integrated design model for building frames structures. The design information and activities involved in the three dimensional building space, the locations of frames, and the grouping of frames represented as entities in the entity-based integrated design model are transformed to C++ codes. Each product or process entity can be basically transformed to an class. The attributes of an entity can be defined as variables and member functions of a class.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 D
• /
• pp.2280-2282
• /
• 2000

This paper presents a simple and new digital redesign algorithm for fussy-model-based controllers. In the first stage, a continuous-time TS fuzzy model is constructed for a given continuous-time nonlinear system and a corresponding continuous-time fuzzy-model-based controller is established based on the existing controller synthesis algorithms. In the second stage, the continuous-time fuzzy-model-based controller is converted to equivalent discrete-time fuzzy-model-based controller, aiming at maintaining the property of the analogue controlled system, which are called intelligent digital redesign. Finally, the proposed method is applied to the digital control of inverted pendulum system to shows the effectiveness and the feasibility of the method.