• Journal of information and communication convergence engineering
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• 제7권4호
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• pp.469-474
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• 2009

Q-algorithm is proposed at EPC global Class-1 Generation-2 RFID systems to determine the frame size of next query round. In Q-algorithm, the reader calculates the frame size without estimating the number of tags. But, it uses only the slot conditions: empty, success, or collision. Therefore, it wastes less computational cost and is simpler than other algorithms. However, the constant parameter C value, which is used for calculating the next frame size, is not optimized. In this paper, we propose the optimized C values of Q-algorithm according to the number of tags within the identification range of reader through a lot of computer simulations.

• 전자공학회논문지A
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• 제33A권2호
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• pp.23-31
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• 1996

This paper proposes a new UPC(usage parameter control) mechanism that varies the token generation rate of leaky bucket by observing virtual buffer, thus achieving an improvement of performance. An acceptance of a call in B-ISDN is determined by call admission control. A UPC that polices the agreed traffic parameters of a call and takes appropriate actions to prevent congestion in networks. The cell loss probability of conventional UPC is far from that of ideal UPC. The proposed mechanism has a better policing ability and response time for nonconforming call. The proposed mechanism uses ON-OFF model as input traffic. The results of simulation show the efficiency of the proposed mechanism.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.13-14
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• 2008

This paper describes the optimal PSS parameter design for the PSS of EX2000 excitation system. The suggested tuning technique uses the model-based PSS tuning method which have three steps: generation system modeling, determination of PSS parameters, and on-site test. Using this method, the PSS parameters of EX2000 system in Dangjin T/P #4 was designed and verified by linear analysis program, PSS/E, and EMTDC/PSCAD.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2005년도 춘계 종합학술대회 논문집
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• pp.410-415
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• 2005

Recent measurements of local-area and wide-area traffic have shown that network traffic exhibits at a wide range of scales - Self-similarity. Self-similarity is expressed by long term dependency, this is contradictory concept with Poisson model that have relativity short term dependency. Therefore, first of all for design and dimensioning of next generation communication network, traffic model that are reflected burstness and self-similarity is required. Here self-similarity can be characterized by Hurst parameter. In this paper, when different many data traffic being integrated under various environments is arrived to communication network, Hurst Parameter's change is analyzed and compared with simulation results.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.114-114
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• 2000

In this paper a self-tuning modified skyhook control for the semi-active suspension systems is investigated. The damping force generation mechanism is modeled We consider a 2 DOF time-varying quarter car model that permits parameter variations of the sprung mass and suspension spring coefficient. The modified skyhook control algorithm proposed in this paper requires only the measurement of body acceleration. The absolute velocity of the sprung mass and the relative velocity of the suspension deflection are estimated by using integral filters, according to parameter variations. The skyhook gains are designed in such a way that the body acceleration and the dynamic tire force are optimized. An ECU prototype will be discussed

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.47-50
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• 1990

Deafs cannot speak straight voice as normal people in lack of feedback of their pronunciation, therefore speech training is required. In this study, fundamental frequency, intensity, formant frequencies, vocal tract graphic and vocal tract area function, extracted from speech signal, are used as feature parameter. AR model, whose coefficients are extracted using inverse filtering. is used as speech generation model. In connect ion between vocal tract graphic and speech parameter, articulation distances and articulation distance functions in selected 15-intervals are determined by extracted vocal tract areas and formant frequencies.

• 비파괴검사학회지
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• 제33권1호
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• pp.1-6
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• 2013

Ultrasonic guided wave techniques have been widely used for long range nondestructive detection in tube-like structures. The present paper investigates the ultrasonic linear and nonlinear parameters for evaluating the thermal damage in aluminum pipe. Specimens were subjected to thermal loading. Flexible polyvinylidene fluoride (PVDF) comb transducers were used to generate and receive the ultrasonic waves. The second harmonic wave generation technique was used to check the material nonlinearity change after different heat loadings. The conventional linear ultrasonic approach based on attenuation was also used to evaluate the thermal damages in specimens. The results show that the proposed experimental setup is viable to assess the thermal damage in an aluminum pipe. The ultrasonic nonlinear parameter is a promising candidate for the prediction of micro-damages in a tube-like structure.

• 설비공학논문집
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• 제10권5호
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• pp.523-534
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• 1998

The convection heat transfer on horizontal circular tube is studied as a conjugated heat transfer problem. With uniform heat generation in a cylindrical heater placed in a cross flow boundary condition, heat flow that is conducted along the wall of the heater creates a non-isothermal surface temperature and non-uniform heat flux distribution. In the present investigation, the effects of circumferential wall heat conduction on convection heat transfer are investigated for the case of forced convection around horizontal circular tube in cross flow of air and water. Non-dimensional conjugation parameter $ K^*$ which can be deduced from the governing energy differential equation should be used to express the effect of circumferential wall heat conduction. Two-dimensional temperature distribution$ T({\gamma,\theta})$ is presented. The influence of circumferential wall heat conduction is demonstrated on graph of local Nusselt number.

• Journal of KIEE
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• 제10권1호
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• pp.16-22
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• 2000

The Main role of the gas turbine lies in the utilization of waste heat which may be found in exhaust gases from the gas turbine or at some other points of the process to produce additional electricity. Up to date, the PID controller has been used to operate under such difficult conditions, but since the gain of PID controller manually experience. In this paper parameter separation type 2-DOF PID controllers are proposed based on the gas turbine control system. Gas turbine transfer function is achieved from operation data of Gun-san gas turbine and Tuning algorithms of parameter separation type 2-DOF PID controller is ANFIS. Results represents satisfactory response.

• Nuclear Engineering and Technology
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• 제51권3호
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• pp.867-876
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• 2019

Second harmonic generation using nonlinear ultrasonic waves have been shown to be an early indicator of possible fatigue damage in nuclear power plant components. This technique relies on measuring amplitudes, making it highly susceptible to variations in transducer coupling and instrumentation. This paper proposes an experimental procedure for in-situ surface wave nonlinear ultrasound measurements on specimen with permanently mounted transducers under high cycle fatigue loading without interrupting the experiment. It allows continuous monitoring and minimizes variation due to transducer coupling. Moreover, relations describing the effects of the measurement system nonlinearity including the effects of the material transfer function on the measured nonlinearity parameter are derived. An in-situ high cycle fatigue test was conducted using two 304 stainless steel specimens with two different excitation frequencies. A comprehensive analysis of the nonlinear sources, which result in variations in the measured nonlinearity parameters, was performed and the effects of the system nonlinearities are explained and identified. In both specimens, monotonic trend was observed in nonlinear parameter when the value of fundamental amplitude was not changing.