• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.914-920
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• 2002

Nonlinear flow-induced vibration characteristics of a generic missile wing (or control surface) are investigated in this study. The wing model has freeplay structural nonlinearity at its pitch axis. Nonlinear aerodynamic flows with unsteady shock waves are considered in the transonic flow region. To practically consider the effects of freeplay structural nonlinearity, the fictitious mass method (FMM) is applied to structural vibration analysis based on a finite element method (FEM). A computational fluid dynamics (CFD) technique is used for computing the nonlinear unsteady aerodynamics of all-movable wings. The aerodynamic analysis is based on the efficient transonic small-disturbance aerodynamic equations of motion using the potential-flow theory. To solve the nonlinear aeroelastic governing equations including the freeplay effect, a modal-based computational structural dynamic (CSD) analysis technique based on fictitious mass method (FMM) is used in time-domain. In addition, CSD and unsteady CFD techniques are simultaneously coupled to give accurate computational results. Various aeroelastic computations have been performed for a generic missile wing model. Linear and nonlinear aeroelastic computations have been conducted and the characteristics of flow-induced vibration are introduced.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.105-113
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• 2018

This paper proposes pre-analysis on planning of high-voltage direct current (HVDC) transmission system applied to Korea electric power grid. HVDC transmission system for interface lines has been considered as alternative solution for high-voltage AC transmission line in South Korea since constructing new high-voltage AC transmission lines is challenging due to political, environmental and social acceptance problems. However, the installation of HVDC transmission system as interface line in AC grid must be examined carefully. Thus, this paper suggests three scenarios to examine the influences of the installation of HVDC transmission system in AC grid. The power flow and contingency analyses are carried out for the proposed scenarios. Power reserves in metro area are also evaluated. And then the transient stability analysis focusing on special protection scheme (SPS) operations is analyzed when critical lines, which are HVDC lines or high voltage AC lines, are tripped. The latest generic model of HVDC system is considered for evaluating the impacts of the SPS operations for introducing HVDC system in the AC grid. The analyses of proposed scenarios are evaluated by electromechanical simulation.

• Advances in aircraft and spacecraft science
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• v.4 no.2
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• pp.185-202
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• 2017

In a flexible airvehicle, an assessment of the structural coupling levels through analysis and experiments provides structural data for the design of notch filters which are generally utilized in the flight control system to attenuate the flexible response pickup. This is necessitated as during flight, closed loop control actuation driven with flexible response inputs could lead to stability and performance related problems. In the present work, critical parameters influencing servoelastic response have been identified. A sensitivity study has been carried out to assess the extent of influence of each parameter. A multi-parameter tuning approach has been implemented to achieve an enhanced analytical model for improved predictions of aircraft servoelastic response. To illustrate the model updation approach, initial and improved test analysis correlation of lateral servoelastic responses for a generic flexible airvehicle are presented.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.5
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• pp.450-457
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• 2004

In this research, the automatic synthesis of knowledge models is proposed. which are the basis of the methods using qualitative models adapted widely in fault diagnosis and hazard evaluation of chemical processes. To provide an easy and fast way to construct accurate causal model of the target process, the Role-Behavior modeling method is developed to represent the knowledge of modularized process units. In this modeling method, Fault-Behavior model and Structure-Role model present the relationship of the internal behaviors and faults in the process units and the relationship between process units respectively. Through the multiple modeling techniques, the knowledge is separated into what is independent of process and dependent on process to provide the extensibility and portability in model building, and possibility in the automatic synthesis. By taking advantage of the Role-Behavior Model, an algorithm is proposed to synthesize the plant-wide causal model, Fault-Causality Graph (FCG) from specific Fault-Behavior models of the each unit process, which are derived from generic Fault-Behavior models and Structure-Role model. To validate the proposed modeling method and algorithm, a system for building FCG model is developed on G2, an expert system development tool. Case study such as CSTR with recycle using the developed system showed that the proposed method and algorithm were remarkably effective in synthesizing the causal knowledge models for diagnosis of chemical processes.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.123-124
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• 2015

국제 전기기술 위원회(International Electro-technical Commission; IEC)에서는 풍력발전 시스템의 표준화된 전력 안정도 연구에 적합한 전기적 시뮬레이션 모델에 대한 규정 IEC 61400-27을 제정 중에 있다. 본 논문에서는 IEC 61400-27에서 제시하고 있는 풍력터빈의 시뮬레이션 모델을 구현하였으며, 이를 통해 규정에서 제시하고 있는 풍력터빈 시뮬레이션 모델의 저전압 사고시 LVRT 제어전략에 따른 특성을 파형을 통해 나타내었다

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.57.5-57
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• 2001

This paper presents an enhanced web-based distributed system with Single Access Object Protocol(SOAP), which uses HTTP as a communication protocol and XML as a data presentation. The suggested system is applied into a Generic Equipment Model (GEM) for exchanging specified messages(SECS-II), which are encoded into XML presentation, between Equipment and Host via the web sorrel. In this paper, the designed system architecture and its soap components are presented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7C
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• pp.670-676
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• 2002

The object of ATM network is to the guarantee quality of service(QoS). Therefore, various of traffic management schemes have been proposed. Among these schemes, call admission control(CAC) is very important to provide real-time services and ON-OFF model, which is single source traffic model, has been used. But ON-OFF model differ from GCRA(Generic Cell Rate Algorithm) controlled traffic in ATM network. In this paper, we analyze the traffic, which is controlled as dual GCRA, and propose TWM(Three-state Worst-case Model), which is new single source traffic model. We also proposed CAC to guarantee peak-to-peak CDV(Cell Delay Variation) based on the TWM. In experiments, ON-OFF model and TWM are compared to show that TWM is superior to ON-Off model in terms of QoS guaranteeing.

• Korean System Dynamics Review
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• v.12 no.1
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• pp.75-87
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• 2011

Congestion problems can be approached from the viewpoint of system dynamics theory. The relationship between road capacity and congestion can be explained by the 'relative control' archetype among four system archetypes suggested by Wolstenholme. There is a balancing feedback loop between road capacity and road congestion. However, there is another balancing loop between road congestion and car traffic volume, which keeps disrupting the equilibrium of the former loop. A system dynamics model, which is based on a partial adjustment model of induced traffic in the literature, is built to simulate three road building scenarios: 'Expanding investment', 'Balancing investment' and 'Frozen road investment' scenarios. The 'Expanding investment' scenario manages to drop congestion levels by 9% over 30 years, however, causing much higher emissions of $CO_2$ than other scenarios. The trade-off relationship between congestion levels and environmental costs must be taken into consideration for road investment policies.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.179-182
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• 1997

In a training simulator for power plant, operator's action in the MCR(Main Control Room) are given to plant process and computer system model as an inputs, and the same response as in real power plant is provided in real time. Inter-process communication and synchronization are especially important among various inputs. In the plant simulator, to simulate the digital control system such as FOXBORO SPEC-200 Micro control system, modification and adaptation of control card(CCC) and its continuous display station(CDS) is necessary. This paper describes the modeling and simulation of FOXBORO SPEC-200 Micro control system applied to Younggwang nuclear power plant unit #3 & 4, and its integration process to the full-scope replica type training simulator. In a simulator, display station like CDS of FOXBORO SPEC-200 Micro control system is classified as ITI(Intelligent Type Instrument), which has a micro processor inside to process information and the corresponding alphanumeric display, and the stimulation of ITI limits the important functions in a training simulator such as backtrack, replay, freeze and IC reset. Therefore, to achieve the better performance of the simulator, modification of CDS and special firmware is developed to simulate the FOXBORO SPEC-200 Micro control system. Each control function inside control card is modeled and simulated in generic approach to accept the plant data and control parameter conveniently, and debugging algorithms are applied for massive coding developed in short period.

• Journal of Food Hygiene and Safety
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• v.19 no.4
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• pp.185-192
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• 2004

Generic HACCP models for bakery products may help HACCP implementation at the wholesale bakery production lines easier. When baking, the internal temperature of bakery products went up to $85^{\circ}C$, which resulted in gelatinization of starch. Considering the characteristics of bakery products, general sanitation control procedures are the main target tool to keep bakery products safe. Monitoring of pathogenic microorganisms at bakery plant environment including production lines was carried out. At the wholesale bakery environment pathogenic microorganisms were detected. It gave a clue that general sanitation control procedures should be implemented for safe bakery products supply. Hazard analysis of raw materials and processing of bakery products, and determination of critical control points and critical limits at the wholesale bakeries lead to present generic model of bakery product HACCP plan. CCPs for the wholesale bakery products may be applied and modified for the implementation of HACCP plan at the wholesale bakery plant.