• Proceedings of the Korea Society for Simulation Conference
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• 1999.10a
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• pp.289-293
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• 1999

디지털 기술을 기반으로 한 조속기 제어시스템의 제어 알고리즘에 대한 적합성과 하드웨어의 신뢰성 시험을 위한 다이나믹 테스트 베드를 구축하기 위해 증기 터빈 및 발전기의 특성을 그대로 모사하는 시뮬레이터 및 하드웨어를 개발하였으며, 개발된 시뮬레이터를 사용자(시험자)가 그 기능들을 적절하고 편리하게 사용할 수 있도록 인간공학의 원칙을 반영하여 설계하였다. 이를 위해 시뮬레이터가 가져야 하는 기능들을 시험 절차의 분석을 통해 도출하고 그 기능들을 사용 목적에 따라 적절하게 그룹핑하였으며, 가장 빈번하게 사용하는 Mimic Display의 경우 사용자가 항상 확인 가능하도록 주 화면에 구성한 인간-기계 연계 설계에 대해 소개하고자 한다.

• Journal of IKEEE
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• v.18 no.3
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• pp.435-441
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• 2014

The V2X cooperative communication system is fusion technology which makes vehicle manuver safer. To evaluate and anticipate effect of these kind of technology, it requires real-car based road construction, implementation of communication devices, hiring inspection specialized personnel. For this reason, many laboratories and universities experience difficulties to test their technology results. Also, the need of implementing reliable testbed for testing vehicle safety applications and V2X communication technology is increasing as V2X device development is being accelerated. In this paper, we implemented a system which synchronizes traffic and network simulators via developing External interface to set simulation based testing environment in order to solve the difficulties.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1721-1724
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• 2005

유비쿼터스 기반 디지털 홈은 하드웨어적 요소인 디지털 홈 공간과 소프트웨어적 요소인 상황인지 에이전트가 결합하여 거주자에게 인간의 삶의 질 향상을 제공하기위해 거주자에게 적합한 서비스를 파악하여 그에게 최적의 서비스들을 제공할 수 있다. 그러나 디지털 홈은 공간은 센서기술과, 센서네트워크 같은 하드웨어적인 제약과 비용 때문에 테스트베드 구축을 통한 상황인지기술에 대한 연구에는 한계가 있다. 본 논문에서는 이러한 한계를 극복하기 위해 디지털 홈의 상황인지 연구를 위한 시뮬레이터를 개발하였으며, 시뮬레이터를 기반으로 상황인지 시스템을 개발하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.5
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• pp.416-422
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• 2016

This paper presents preliminary performance analysis of a satellite formation flying testbed, which is under development by Astrodynamics and Control Laboratory, Department of Astronomy, Yonsei University. A model reference adaptive controller (MRAC) with a first-order reference model is chosen to enhance the response of reaction wheel system which is subject to uncertainties caused by unmodelled dynamics and measurement noise. In addition, an on-line parameter estimation (OPE) technique based on the least square is combined to eliminate the effect of angular measurement noise by estimating the moment of inertia. Both numerical simulations and hardware experiments with MRAC support the effectiveness and applicability of the adaptive control scheme, which maintains the tracking error below $0.25^{\circ}$ for the entire time span. However, the high frequency control input generated in hardware experiment strongly suggests design modifications to reduce the effect of deadzone.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.01a
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• pp.73-74
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• 2016

네트워크 연구 분야에서 실시간 시나리오로 네트워크를 구성하는 것은 제약 사항이 많다. 단 하나의 테스트 베드도 비용과 시간을 굉장히 많이 소모하기 때문에 실제로 네트워크 전체를 구성하는 것 또한 쉽지 않으며 비용소모가 크다. 시뮬레이터는 이러한 실제 비용과 시간의 제약사항을 완화하여 시스템이 어떻게 동작 할지 알아보는데 도움을 준다. 본 논문에서는 서로 다른 몇 가지 네트워크 시뮬레이터의 주요 기능을 소개하고 장점과 단점을 도출해냈다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.10
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• pp.1947-1957
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• 2015

CCN networking is one of the future internet. With the rapid development of network platforms emerged a wide range of services through a virtual network environment. The performance of CCN in the high bandwidth delay is important to provide various services between nations. We can check the high bandwidth delay product in federation. Federation between the nations has the advantage of being effective to do a various services for the users, and the remote heterogeneous physical hardware engine supports various environments. Data transmission delay can be occur in long distance network even though the network is federated network. In this paper, we propose CCN-Helper protocol for data transmission delay in ling distance networks. We connect from KREONET in Korea to iLab.t in Belgique in order to test CCNx over heterogeneous federated environment.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.1
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• pp.63-71
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• 2012

Most of sensor networks are difficult to be debugged, verified, and upgraded once they are deployed in the fields, for they are usually deployed in real world and large scale. Therefore, before deploying the sensor networks, we should test and verify them sufficiently in realistic testbeds. However, since we need to control physical environments which interact with sensor networks, it takes much of time and cost to test and verify sensor networks at the level of resource-constrained sensor nodes in such environments. This paper proposes an efficient software framework for evaluating and verifying sensor networks in the view points of network and application operations (i.e., accuracy of sensing algorithms). Applying the proposed software framework to the development of a simulator for a smart parking application based on wireless sensor network, this paper verifies the feasibility of the proposed framework.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1059-1067
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• 2006

AODV(Ad-hoc On-demand Distance Vector) routing protocol was devised for use of mobile nodes in Ad-hoc network. When we use the AODV routing protocol in Ad-hoc networks with high mobility, disturbance of optimized route path and link break occur. In order to solve the shortcomings, this paper proposes a new routing protocol in which new routing control messages are added to the existing AODV. The proposed protocol minimizes link break and transmission delay while is able to secure the optimized route path constantly in changes of network topology The performance of the proposed routing protocol was evaluated by using us2 network simulator. The actual Ad-hoc network test bed provides us the most reliable experimental data for Ad-hoc networks. In order to support this experimental environment, the dissertation also developed an efficient embedded system on which AODV routing protocol, NAT, Netfilter can run and other event message can be verified without declining efficiency. The correct operation of AODV routing protocol has been verified in both the Ad-hoc network test bed in which the embedded system was used, and Ad-hoc networks linked with Ethernet backbone network.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.123-124
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• 2022

자율운항선박 원격제어시스템의 실습선 한나라호를 이용한 실험을 수행하기 위한 하드웨어부분과 소프트웨어 부분의 환경조성이 필요하다. 본 연구에서는 이를 진행하기 위한 육상제어센터(SRC)와 실습선의 실험환경 구축현황을 제시하였다. 현재 SRC에는 육상측의 육상제어콘솔, 선박제어모사장치, 메시지교환서버, 네트워크 장치를 설치완료하였으며, 선박측에는 선박제어모사장치, 메시지교환서버, 네트워크장치, 선박시뮬레이터를 설치완료하였다. 자율운항선박의 원격제어에 필요한 테스트베드 설치가 진행중이며, 향후 이에 대한 통합운용시스템 구축을 통해 핵심모듈정상작동여부를 판단하여 저해요인을 식별하고 이를 제거 및 방지하기 위한 방법에 대해 제안하고자 한다.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.4
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• pp.286-290
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• 2011

LBS(Location Based System) is the essential technology of ubiquitous market and utilizes the GNSS(Global Navigation Satellite). GNSS includes GPS of USA, Galileo of Europe Union, QZSS of Japan, Compass of China, and IRNSS of India. Related researches have recently been conducted. Once the satellite is launched, the maintenance such as modification and verification of its function is difficult. Therefore, before the launch of satellites, more precise and concrete verification of performance and operations are needed. In order to do this, hardware testbed may be developed. but software simulators can provide more flexible and cost effective simulation results. These simulators should provide the essential function handling all kinds of error features experienced upon propagation of the GNSS signal. In this paper, we present a design and implementation results of a window-based simulator applying the modeling of various error features for several GNSS.