• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.505-508
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• 2000

We discuss simulation results concerning the performance of the TCP protocol when running over high-speed HFC networks. Hybrid Fiber Coaxial are likely to provide fast and cost effective sup-port to a variety of applications including Video on demand, interactive computer games, and internet-type applications such as Webbrowsing, ftp, and telephony. Since most of these applications, use TCP as the transport later protocol, the key to their success largely depends on the effectiveness of the TCP protocol. In all simulation scenarios the TCP traffic is maxed with some background traffic whose level is taken as a variable parameter. Both the background traffic and TCP traffic are either unshaped, or shaped according to the GCRA algorithm. The effect of the background traffic on the TCP protocol performance is discussed varying the buffering capacity with nodes as well as the peak bit rate that each TCP connection is allowed to use.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.287-288
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• 2007

This paper is for a Real-time Active Control System to operate a boiler. By sensing of flame we wanted to get status of a furnace as many as possible, like load, efficiency, and/or amount of pollutant. These data can be used to make optimal running point by controlling the ratio of air and fuel. So the last object is to make a closed actual control loop from optical head to valve controllers. The first job was to design and to develop a optical data acquisition system. including optical sensor module. And we gathered flame data in variable situations for taking the trend of flame against burning environment. Currently we are developing a general system model, designing some control strategy and testing this active control system.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.761-768
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• 2018

In this paper, the performance analysis of a control topology based on the direct output power control (DPC) for robust and inexpensive permanent magnet-assisted synchronous reluctance generator (PMa-SynRG) system is presented. The PMa-SynRG might be coupled to an internal combustion engine running at variable speed. A three-phase PWM rectifier rectifies the generator output and supplies the dc link. A single-phase PWM inverter supplies constant ac voltage at constant frequency to the grid. The overall control algorithm is implemented on a TMS320F2812 digital signal processor board. Simulations results and experimental results verify the operation of the proposed system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2626-2634
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• 1997

The purpose of multicasting is to reduce the network costs for transmitting the same traffic to multiple destinations. In this paper, an efficient delay-bounded multicasting routing algorithm is proposed, which satistifies the network conditions of cost minimization and can adjust the dynamic events, such as 'leave and/or join ones' from the multicast group. Also, our algorithm is designed for various network requirements such as the efficiet dynamic group support, high-quality data distribution, and adaptability to variable situation. After the delay tolerance and the maximum group size are determined according to network state and requirements for delay and cost, the dynamic delay-bounded multicast tree is constructed using partial multicast routing. We evaluate the performance of the proposed algorithm by running simulations on randomly generated test networks using a Sun Sparc 20 workstation. We were able to obtain good simulation resutls, which means solutions that lies between the minimum cost solution and the minimum delay one.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.11
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• pp.1020-1026
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• 2013

An accurate railway environmental noise prediction model is required to make the proper solution of the railway noise problems. In this paper, an engineering model for predicting the noise of conventional passenger cars is presented considering the acoustic source strength in octave-band frequencies and the propagation over grounds with varying surface properties. Since the formation of a train can be variable, the source strength of each locomotive and passenger car was estimated by measuring the pass-by noise and analysing the wheel-rail rolling noise. Some validation cases show on the average small differences between the predictions of the present model and the measurement results.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.179-182
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• 2004

무선통신분야에서 LMS5(Least Mean Square) 알고리즘은 식이 간단하고 계산량이 비교적 적기 때문에 널리 사용되고 있다. 그러나 시간영역에서 처리할 경우 입력신호의 고유치 변동폭이 넓게 분포되어 수렴속도가 저하하는 문제점이 있다. 이를 해결하기 위하여 신호를 FFT(Fast Fourier Trasnform)나 DCT(Discrete Cosine Transform)로 변환하여 신호간의 상관도를 제거함으로써 시간영역에서 LMS알고리즘을 적용할 때 보다 수렴속도를 크게 향강시킬 수 있다. 본 논문에서는 수렴속도 향상을 위해 시간영역의 적응 알고리즘을 직교변환인 고속웨이브렛(wavelet)변환을 이용하여 변환영역에서 수행하며, 짧은 필터계수를 가지는 DWT(Discrete Wavelet Transform)특성에 맞는 Fast running FIR 알고리즘을 이용하여 WTLMS(Wavelet Transform LMS)적응알고리즘을 통신시스템에 적용한다. 적응 알고리즘의 성능향상을 위하여 시간에 따라 적응상수의 크기를 가변시켜 수렴 초기에는 큰 적응상수로 따른 수렴이 가능하도록 하고 점차 적응상수의 크기를 줄여서 misadjustment도 줄이는 방법의 적응 알고리즘을 제안하였다. 제안한 알고리즘을 실제로 적응잡음제거기(adaptive noise canceler)에 적용하여 컴퓨터 시뮬레이션을 하였으며, 각 알고리즘들의 계산량, 수렴속도를 이용하여 각각 비교, 분서하여 그 성능이 우수함을 입증하였다.

• KEPCO Journal on Electric Power and Energy
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• v.7 no.1
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• pp.85-91
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• 2021

With the social atmosphere of respect for human life and the increasing interest in safety of field workers, research and development is underway in various ways to transform direct live method into indirect live method in the field of distribution. As part of this measure, it was necessary to convert electric pole and complex facilities work from machining power distribution to indirect live operation, and install a straight connecting sleeve that connects cut wires for by-pass method, but it failed to meet the tensile strength standard when constructing a sleeve constructed by direct method. In this paper, the design factors were derived based on the case of overseas similar sleeves and the tensile strength evaluation of each variable was performed, based on the analysis of these test results, the method for securing tensile strength of straight-line access sleeves for indirect running was presented.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.244-247
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• 1999

This paper presents a methodology of the technique for controlling DC motor drive by implementation of 2-quadrant operating mode which can ensure the torque controlling and speed with response time less than 2 seconds at all loading conditions. By implementation of BRM technique, energy is fed with definite values of BRM 256 bits, with different patterns of high accuracy, and fixing scan time at 0.667 ms, the ripple is less than 1%, thus high efficiency can be achieved, from the consequence of the accuracy of energy feeding at low current. The stability of the whole system can be determined from circle criterion by root locus method . The instant reverse direction of rotation can be done by decreasing the energy to the lowest level while motor is running with no load and variable load at the speed about 100-120 rpm and 50-60 rpm.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.7
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• pp.693-699
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• 2011

Internal combustion engines running on syngas, which can be obtained from biomass or organic wastes, are expected to be one of the suitable alternatives for power generation, because they are environment-friendly and do not contribute to the depletion of fossil fuels. However, syngas has variable compositions and a lower heating value than pure natural gas, owing to which the combustion conditions need to be adjusted in order to achieve stable combustion. In this study, a gas that has the same characteristics as syngas, such as low heating value (LHV), was produced by mixing $N_2$ with compressed natural gas (CNG). In addition, this study investigates the combustion characteristics of syngas when it is mixed with hydrogen in a ratio ranging from 10% to 30% with a constant LHV of total gas.

• Convergence Security Journal
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• v.13 no.3
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• pp.17-23
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• 2013

Clustering is required to configure clustering interdependent structural technology. Clustering handles variable workloads or impede continuity of service to continue operating in the event of a failure. Long as high-availability clustering feature focuses on server operating systems. Active-standby state of two systems when the active server fails, all services are running on the standby server, it takes the service. This function switching or switchover is called failover. Long as high-availability clustering feature focuses on server operating systems. The cluster node that is running on multiple systems and services have to duplicate each other so you can keep track of. In the event of a node failure within a few seconds the second node, the node shall perform the duties broken. Structure for high-availability clustering efficiency should be measured. System performance of infrastructure systems performance, latency, response time, CPU load factor(CPU utilization), CPU processes on the system (system process) channels are represented.