• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.12
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• pp.1417-1422
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• 1991

In this paper we develop an analytic model for end-to-end communication protocols and study the window mechanism for flow control in store-and-forward computer networks. We develop a flow control model in which the parameters of the system are not dynamically adjusted to the stochastic fluctuation of the system load. Simulation results are presented and it is shown that the throughput-delay performance of a network can be improved by proper selection of the design parameter, such as timeout, the number of retransmission, etc.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2616-2618
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• 2001

본 논문에서는 홈 오토메이션용 제어 통신망에 널리 사용되는 Ethernet, CEBus, Lonworks 통신규약에 대해서 성능을 분석하고 이를 평가한다. 각 통신시스템의 MAC 규약을 살펴보고 시간 해석에 관한 분석을 제시한다. 본 논문에서는 평균 지연 시간, 네트워크 이용률, 전송 성공 확률 등을 성능분석의 지표로 사용한다. 이를 이용하여 각 통신 규약에 대해 시뮬레이션 결과를 비교, 분석한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1597-1600
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• 2003

컴퓨터시스템은 여러 가지 복잡하고 민감한 시스템을 제어하는데 광범위하게 쓰이고 있다. 최근에 와서는 운영시스템, 제어프로그램, 적용프로그램과 같은 여러 가지 소프트웨어 시스템이 더욱더 복잡화 및 대형화되고 있기 때문에 신뢰성이 높은 소프트웨어 시스템을 개발하는 일이 매우 중요하며, 소프트웨어 제품개발에 있어서 소프트웨어의 신뢰도가 핵심사항이다. 1970년대 이후 소프트웨어의 신뢰성을 향상시키기 위한 여러 가지 소프트웨어의 신뢰도 모델이 제시되고 검토되었으며, 특히, 소프트웨어 개발 후 테스트단계에 적용하는 신뢰도를 추정하고 예측하는 모델이 많이 개발되었다. 소프트웨어가 주어진 시간간격동안 고장이 발생하지 않을 확률 즉, 신뢰도는 소프트웨어의 테스트과정을 계속해서 반복 및 수정하면 더욱 더 증가된다. 그러한 결함검출현상을 설명해주는 소프트웨어 신뢰도 모델을 소프트웨어 신뢰도 성장 모델(SRGM)이라 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1372-1377
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• 2013

In this Paper, a back propagation neural network learning algorithm based on the complex multilayer perceptron is represented for controling and detecting interference of the received signals in cellular mobile communication system. We proposed neural network adaptive correlator which has fast convergence rate and good performance with combining back propagation neural network and the receiver of cellular. We analyzed and proved that NNAC has lower bit error probability than that of traditional RAKE receiver through results of computer simulation in the presence of the tone and narrow-band interference and the co-channel interference.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.1 s.232
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• pp.139-144
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• 2005

A vehicle cruise control algorithm using an Interacting Multiple Model (IMM)-based Multi-Target Tracking (MTT) method has been presented in this paper. The vehicle cruise control algorithm consists of three parts; track estimator using IMM-Probabilistic Data Association Filter (PDAF), a primary target vehicle determination algorithm and a single-target adaptive cruise control algorithm. Three motion models; uniform motion, lane-change motion and acceleration motion. have been adopted to distinguish large lateral motions from longitudinal motions. The models have been validated using simulated and experimental data. The improvement in the state estimation performance when using three models is verified in target tracking simulations. The performance and safety benefits of a multi-model-based MTT-ACC system is investigated via simulations using real driving radar sensor data. These simulations show system response that is more realistic and reflective of actual human driving behavior.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.3
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• pp.542-546
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• 2009

In this Paper, a back propagation neural network learning algorithm based on the complex multilayer perceptron is represented for controling and detecting interference of the received signals in cellular mobile communication system. We proposed neural network adaptive correlator which has fast convergence rate and good performance with combining back propagation neural network and the receiver of cellular. We analyzed and proved that NNAC has lower bit error probability than that of traditional RAKE receiver through results of computer simulation in the presence of the tone and narrow - band interference and the co-channel interference.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.408-414
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• 2005

The VCDRO(Voltage Controlled Dielectric Resonate. Oscillator) with low phase noise is designed using nonlinear analysis, and its phase noise characteristics are compared with that of Lesson's equation. The microstripline coupled with dielectric resonator is realized as a high impedance inverter to improve the phase noise performance, and the quality factor of resonator circuit can be transferred to active device with the enhanced the loaded quality factor. The worst case and part stress analyses are achieved to obtain the high reliability of VCDRO and the reliability analysis is accomplished to estimate the probability of operation at the end of life. The developed VCDRO has the oscillating tuning factor of 0.56MHZ1V for the control voltage range of 0-l2V. This VCDRO requires the DC power of 136mW. The phase noise characteristics exhibit good performances of -94.18dBc/Hz (a)10KHz and -116.3dBc/Hz (a)100KHz. And, the output power over 7.33dBm is measured.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1A
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• pp.9-17
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• 2004

Adapt ive and fixed step size PC (power control) schemes for accommodating voice, video, and data are evaluated according to the different PC command rates and their effects on integrated Voice/Video/Data are investigated. The required minimum power levels are derived as PC thresholds and the effects of PC errors on channel quality and radio 1 ink capacity are investigated. The services with high bit rates and low bit error rates can cause a significant effect on the radio link qualifies of the other types of traffic. The results show that the adapt ive step size PC scheme for voice/video/data services can achieve more capacity and cause less interference to the radio channels because less minimum PIL(Power Increment Level) is required for the specified radio link outage probability.

• Journal of Digital Contents Society
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• v.19 no.5
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• pp.1011-1019
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• 2018

Existing exploration robot is able to control its speed using technologies such as the remote control and deep learning. However its speed control method using weather information has not been proposed. To overcome the problem of conventional methods without using the weather information which is an useful ordinary life information, this paper proposes a new speed control method of exploration robot using weather information gathered from RSS service which is offered without cost by the Meteorological Agency. The exploration robot implemented in this paper is controled by the remote control through the TCP/IP communication and provides real-time real spot figure gathered from its camera sensor within the range of WiFi. Additionally, according to the weather information from URL of the Meteorological Agency, the implemented exploration robot autonomously controls it speed. The correct performance of the proposed method is verified by the experimental measurement data of its speed according to the precipitation probability and wind speed in this paper.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.6 s.52
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• pp.47-56
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• 2006

A method is presented for evaluating the economic efficiency of a semi-active magneto-rheological (MR) damper system for cable-stayed bridges under earthquake loadings. An optimal MR damper capacity maximizing the cost-effectiveness is estimated for various seismic characteristics of ground motion. The economic efficiency of MR damper system is addressed by introducing the life-cycle cost concept. To evaluate the expected damage cost, the probability of failure is estimated. The cost-effectiveness index is defined as the ratio of the sums of the expected damage costs and each device cost between a bridge structure with the MR damper system and a bridge structure with elastic bearings. In the evaluation of cost-effectiveness, the scale of damage cost is adopted as parametric variables. The results of the evaluation show that the MR damper system can be a cost-effective design alternative. The optical capacity of MR damper is increased as the seismic hazard becomes severe.