• 한국국방경영분석학회지
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• 제7권2호
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• pp.63-99
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• 1981

The generalized goal decomposition model proposed by Ruefli as a single period decision model is presented for the purpose of a review and extended to make a multiple period planning model. The multiple period planning model in the three level organization is formulated with, linear goal deviations by introducing the goal programming method. Dynamic formulation using the generalized goal decomposition model for each single period problem is also presented. An iterative search algorithm is presented as an appropriate solution method of the dynamic formulation of the multiple period planning model.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.337-342
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• 2003

The dynamic load effects are conveyed to the railway bridges through tracks which are generated by moving trains The dynamic load effects may vary due to the dynamic characteristics of the applied vehicle loads and the railway bridges containing the track system. However, the track effects have been neglected or simplified by spring elements in the most studies since it is quite complex to consider the track systems in the dynamic analysis models of railway bridges. In this study, track system on railway bridges is modeled using a three-dimensional discrete-support model that can simulate the load carrying behavior of tracks. In addition, this program is developed with the precise 20-car model and a continuous PSC(prestressed concrete) box girder bridge, which is the main bridge type of Korea Train express(KTX). Three-dimensional elements are used for both. The dynamic response of railway bridges is found to be affected depending on whether the track model is considered or not. The influencing rate depends on the traveling speed and different wheel-axle distance. The dynamic bridge response is decreased remarkably by the track systems around the resonant frequency. Therefore, the resonance effect can be reduced by modifying the track properties in the railway bridge.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.981-988
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• 2018

In order to acquire an accurate TOF, this paper proposes a method that produces TOF by using a mathematical model for the envelope of the received signal obtained from a system dynamic model of ultrasonic transducer. The proposed method estimates the arrival time of the received signal retrospectively by comparing its wave form obtained after triggering point with its mathematical envelope model. Experimental result shows that the error due to variation of triggering point can be dramatically decreased by implementing the proposed method.

• 대한교통학회지
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• 제11권1호
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• pp.67-86
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• 1993

A formulation of dynamic traffic assignment between multiple origins and single destination was first introduced in 1987 by Merchant and Nemhauser, and then expanded for multiple destination in the late 1980's (Carey, 1987). Based on behavioral choice theory which provides proper demand elasticities with respect to changes in policy variables, traffic phenomena can be analysed more realistically, especially in peak periods. However, algorithms for these models are not well developed so far(working with only small toy network) and solutions of these models are not unique. In this paper, a new model is developed which keeps the simplicity of static models, but provides the sensitivity of dynamic models with changes of O-D flows over time. It can be viewed as a joint departure time and route choice model, in the given time periods(6-7, 7-8, 8-9 and 9-10 am). Standard multinomial logit model has been used for simulating the choice behavior of destination, mode, route and departure time within a framework of the incremental network assignment model. The model developed is workable in a PC 386 with 175 traffic zones and 3581 links of Seoul and tested for evaluating the exclusive use of Namsan tunnel for HOV and the left-turn prohibition. Model's performance results and their statistical significance are also presented.

• 한국강구조학회 논문집
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• 제12권4호통권47호
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• pp.407-416
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• 2000

본 연구는 실험적인 방법으로 이동하중을 받는 판형교의 동적 응답을 연구하였다. 판형교의 상부 슬래브는 판요소로, 거더는 보요소로 이상화였다. 이동하중과 판형교는 각각 소규모 차량모델과 교량모델로 제작하였다. 이동 하중을 받는 판형교의 동적 응답은 변형계, 변위계, 가속도계 및 변형도 측정기를 이용하여 측정하였고 측정한 자료로부터 얻은 최대동적응답을 유한요소법의 결과와 비교하였다. 실험적인 모형실험으로 판형교의 동적응답을 얻을 수 있음을 알 수 있다.

• 대한의용생체공학회:의공학회지
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• 제25권4호
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• pp.301-307
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• 2004

보행 중 각 관절의 모멘트를 계산하기 위한 역동역학 모델을 개발하였다. 모델은 1개의 상체와 3개의 체절로 하지를 구성하였고 3개의 병진 조인트와 12개의 회전조인트로 각 체절을 연결하고 뉴턴-오일러 방법으로 역동역학 해를 구하였다. 입력자료로서의 기구학적 사료는 3차원 동작분석 시스템에서 추출하였고 외력으로서 지면 반발력은 동기화한 힘측정판에서 구했다. 개발된 모델을 이용하여 비대칭 모델이나 질량중심의 이동을 포함한 해석 등 다양한 인체운동 해석이 가능하다.

• 대한교통학회지
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• 제26권6호
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• pp.123-132
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• 2008

동적(dynamic) 기종점(origin-destination, OD) 통행량은 다양한 교통분야에 활용이 가능한데, 대표적으로 동적 통행배정모형의 입력자료와 같은 교통계획분야와 실시간 도로교통 운영분야, 그리고 교통수요 관리분야 등에도 사용할 수 있다. 이런 교통정책들을 평가하기 위해서는 정확한 동적 OD통행량의 추정은 무엇보다 중요하며, 이를 위하여 다양한 기법들이 제시되고 있다. 본 연구에서는 최근 새롭게 연구되고 있는 개인이 소지한 통행 단말기 정보를 이용하여 동적 OD통행량을 추정하고 이를 평가하고자 한다. 이를 위하여 동적 OD추정모형을 개발하고 개발된 추정모형과 동적 통행배정모형(DYNASMART-P)을 이용하여 동적 OD통행량을 추정하는데, 동적OD통행량 추정시 이용되는 단말기 정보가 표본자료(sample data)이기 때문에 이를 전수화하는 과정이 포함된다. 본 연구에서 제안한 방법으로 제주시를 대상으로 동적OD통행량을 추정한 결과, 그 가능성을 확인할 수 있었다.

• ETRI Journal
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• 제34권4호
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• pp.633-636
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• 2012

A dynamic analysis of an amorphous silicon (a-Si) thin film transistor liquid crystal display (TFT-LCD) pixel is presented using new a-Si TFT and liquid crystal (LC) capacitance models for a Simulation Program with Integrated Circuit Emphasis (SPICE) simulator. This dynamic analysis will be useful when predicting the performance of LCDs. The a-Si TFT model is developed to accurately estimate a-Si TFT characteristics of a bias-dependent gate to source and gate to drain capacitance. Moreover, the LC capacitance model is developed using a simplified diode circuit model. It is possible to accurately predict TFT-LCD characteristics such as flicker phenomena when implementing the proposed simulation model.

• Steel and Composite Structures
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• 제10권6호
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• pp.541-561
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• 2010

This paper presents finite element analyses, experimental measurements and finite element model updating of an arch type steel laboratory bridge model using semi-rigid connections. The laboratory bridge model is a single span and fixed base structure with a length of 6.1 m and width of 1.1m. The height of the bridge column is 0.85 m and the maximum arch height is 0.95 m. Firstly, a finite element model of the bridge is created in SAP2000 program and analytical dynamic characteristics such as natural frequencies and mode shapes are determined. Then, experimental measurements using ambient vibration tests are performed and dynamic characteristics (natural frequencies, mode shapes and damping ratios) are obtained. Ambient vibration tests are performed under natural excitations such as wind and small impact effects. The Enhanced Frequency Domain Decomposition method in the frequency domain and the Stochastic Subspace Identification method in the time domain are used to extract the dynamic characteristics. Then the finite element model of the bridge is updated using linear elastic rotational springs in the supports and structural element connections to minimize the differences between analytically and experimentally estimated dynamic characteristics. At the end of the study, maximum differences in the natural frequencies are reduced on average from 47% to 2.6%. It is seen that there is a good agreement between analytical and experimental results after finite element model updating. Also, connection percentages of the all structural elements to joints are determined depending on the rotational spring stiffness.

• 시스템엔지니어링학술지
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• 제11권2호
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• pp.75-83
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• 2015

This paper describes modeling & simulation(M&S) model for dynamic analysis of helicopter rotor blades. Simulation model is developed using Dymola tool which implements the open source language - Modelica. Modelica is appropriate for developing multibody dynamic analysis model. To develop an M&S model efficiently, model based systems engineering(MBSE) is applied. Some diagrams such as requirement diagram, block definition diagram and sequence diagram etc. are drawn to capture the concept of M&S model. This activity is done utilizing the open source tool - Papyrus.