• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.109-112
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• 2005

In this paper, we propose an improved delay-constrained unicast routing (I-DCUR) algorithm for real-time networks which is based on the delay-constrained unicast routing (DCUR) algorithm. Our I-DCUR algorithm is quite different from DCUR algorithm, because the node will choose the link between the active node and the previous node, and it will replace the original loop path when it detects a loop. Thus, firstly consider to choose the link between the active node and the previous node to replace the original loop path when a node detects a loop. So our algorithm can make the construction of path more efficiently, as compared to DCUR algorithm. We could see that the performance of I-DCUR algorithm is much better than DCUR algorithm in the experimental results. There were over 40% improvement in 100 nodes, 60% in 200 nodes, and 9% reduction of costs.

• 한국CDE학회논문집
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• 제9권2호
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• pp.148-157
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• 2004

Interactive simulators that simulate mechanical systems are being developed for the purpose of performance evaluation of product design, replacement of physical training, and entertainment game. Use of flight simulator is increasing to reduce risk and cost of physical training, and we need virtual environment which covers large area terrain. We need a method that can reduce development cost and construction time of virtual environment that simulate the real environment. There have been attempts to link GIS or remote sensing field with virtual reality. This paper examines a method that helps to construct virtual environment, and attempts to link geographic information with virtual reality. A construction method of virtual environment based on digital map and satellite image has been studied.

• 대한교통학회지
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• 제6권1호
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• pp.5-16
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• 1988

Development is given to an optimal network design method using continuous design variables. Modified Hooke-and-Jeeves algorithm is implemented in order to solve nonlinear programming problem which is approximately equivalent to the real network design problem with system efficiency crieteria and improvement cost as objective function. the method was tested for various forms of initial solution, and dimensions of initial step size of link improvements. At each searching point of evaluating the objective function, a link flow problem was solved with user equilibrium principles using the Frank-Wolfe algorithm. The results obtained are quite promising interms fo numbers of evaluation, and the speed of convergence. Suggestions are given to selections of efficient initial solution, initial step size and convergence criteria. An approximate method is also suggested for reducing computation time.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1495-1500
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• 2004

The interface link for railway signaling systems is generally point-to-point communication scheme, but there have been several efforts to apply the network technology to these interface link in overseas country. However general Ethernet scheme has several drawbacks, so this scheme cannot meet the very high reliability, safety and real-time properties. To overcome these drawbacks, there have been studies reduction and modeling of data collision probability for this ethernet at the industrial and academic world. Therefore, in this paper we analyzed describe a interface trend using network technology between railway signaling equipments and will describe a major technology and framework of a network for railway signaling system.

• Journal of Communications and Networks
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• 제7권2호
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• pp.222-230
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• 2005

This article presents a field evaluation of an IP-based architecture for heterogeneous environments that has been developed under the aegis of the Moby Dick project, covering UMTS-like (universal mobile telecommunications system) TD-CDMA (time division-code division multiple access) wireless access technology, wireless and wired LANs. The architecture treats all transmission capabilities as basic physical and data-link layers, and replaces all higher-level tasks by IP-based strategies. The Moby Dick architecture incorporates mobile IPv6, fast handovers, AAA-control (authentication, authorisation, accounting), charging and quality of service (QoS) in an integrated framework. The architecture further allows for optimised control on the radio link layer resources. It has been implemented and tested by expert users, and evaluated by real users on field trials with multiple services available.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.500-503
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• 1990

Neural network is a computational model of the biological nervous system developed to exploit its intelligence and parallelism. Applying neural networks to robots creates many advantages over conventional control methods such as learning, real-time control, and continuous performance improvement through training and adaptation. In this paper, dynamic control of a six-link robot will be presented using neural networks. The neural network model used in this paper is the backpropagation network. Simulated control of the PUMA 560 arm shows that it can move at high speed as well as adapt to unforseen load changes. The results are compared with the conventional PD control scheme.

• 한국자동차공학회논문집
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• 제8권3호
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• pp.98-109
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• 2000

A new PC-based Engine Control system (ECS) is developed using an object oriented programming method. This system provides more convenient environment for engine tests, easier user interface and extended functions. A Windows-based ECS software is developed with class, and the class structure is built on encapsulation and abstraction. The closed-loop engine control scheme can be easily constructed by using dynamic link library and multitasking. This means that a user can perform desired experiments without clear knowledge of the hardware structure of the ECS. Also this system allows a user to individually control the ignition and fuel injection for each cylinder in a simple manner such as through a keyboard/mouse or in a real-time operation from a closed-loop control program.

• 전자공학회논문지B
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• 제31B권12호
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• pp.137-144
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• 1994

In this paepr, we present a soft switching PWM inverter as reducing switching loss and stress at high power application. The PWM inverter is designed by space voltage about 2$\sqrt{3}$ times (15%) than conventional SPWM method. To reduce switching loss and stress. The DC link requires a capacitor, an inductor and two additional switches. Therefore proposed inverter performs trun PWM operation under the soft switching condition. As a result of soft switching we can reduce switching loss and ensure stability of switching devices. For approach to real time, control system is realized by 8 bit single-chip microprocessor. Therefore, we can construct system is with simplified volumn and structure by eliminating carrier wave and referrence wave generator of conventional SPWM method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.69.6-69
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• 2001

The SSPA makes the power level of EIRP up to 16W, and compensates for temperature to the SSPA´s maximum stability. The up and the down converters are dually conversed like as individual synthesizers for selecting of independent transmit-receive transponder. The function of the up-converter is to convert the 70MHz IF signal modulated in the indoor unit modem into a 14.0 ∼ 14.5 GHz Ku-band up-link signal to be sent to the antenna. The down-converter converts the 12.25 ∼ 12.75 GHz Ku-band down-link signal or a trouble malfunction of SSPA may be a fatal factor to operation of the whole satellite communication network. Therefore, this study developed the remote monitoring and control program to monitor the SSPA´s status before the problem occurs for stable operation of the system. This software ...

• 대한공간정보학회지
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• 제16권3호
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• pp.29-34
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• 2008

차량용 네비게이션 시스템은 자가 운전 차량의 증가, 여가 문화 확산 등으로 수요가 폭발적으로 증가하고 있으며, 실시간 교통 정보, 디지털 멀티미디어 방송 등의 기능이 융합되면서 텔레매틱스의 가장 중요한 분야로 급성장하고 있다. 이러한 네비게이션 시스템의 다양한 구성 요소 중 네트워크 데이터는 실세계의 도로망을 반영하며, 경로탐색의 기반이 되는 데이터로 가장 핵심 요소라 할 수 있다. 하지만, 현재의 네비게이션 시스템은 stand-alone 형태로 단말기 내의 네트워크 데이터는 자체가 과거의 데이터로 이를 보완하기 위하여 사용자는 주기적으로 업데이트를 수행해야 하는 단점을 가지고 있다. 따라서 본 연구에서는 무선 통신을 활용하여 사용자가 요구하는 경로를 검증하여 항상 최신의 네트워크 데이터를 활용할 수 있는 기법을 제안하고 시뮬레이션을 통하여 제안 기법의 타당성을 검증하였다.