• Title/Summary/Keyword: Comparison time constant

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The Study for Software Future Forecasting Failure Time Using Time Series Analysis. (시계열 분석을 이용한 소프트웨어 미래 고장 시간 예측에 관한 연구)

  • Kim, Hee-Cheul;Shin, Hyun-Cheul
    • Convergence Security Journal
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    • v.11 no.3
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    • pp.19-24
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    • 2011
  • Software failure time presented in the literature exhibit either constant monotonic increasing or monotonic decreasing, For data analysis of software reliability model, data scale tools of trend analysis are developed. The methods of trend analysis are arithmetic mean test and Laplace trend test. Trend analysis only offer information of outline content. In this paper, we discuss forecasting failure time case of failure time censoring. In this study, time series analys is used in the simple moving average and weighted moving averages, exponential smoothing method for predict the future failure times, Empirical analysis used interval failure time for the prediction of this model. Model selection using the mean square error was presented for effective comparison.

The Study for Software Future Forecasting Failure Time Using Curve Regression Analysis (곡선 회귀모형을 이용한 소프트웨어 미래 고장 시간 예측에 관한 연구)

  • Kim, Hee-Cheul;Shin, Hyun-Cheul
    • Convergence Security Journal
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    • v.12 no.3
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    • pp.115-121
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    • 2012
  • Software failure time presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing. For data analysis of software reliability model, data scale tools of trend analysis are developed. The methods of trend analysis are arithmetic mean test and Laplace trend test. Trend analysis only offers information of outline content. In this paper, we discuss forecasting failure time case of failure time censoring. In this study, we predict the future failure time by using the curve regression analysis where the s-curve, growth, and Logistic model is used. The proposed prediction method analysis used failure time for the prediction of this model. Model selection using the coefficient of determination and the mean square error were presented for effective comparison.

The Comparison of Activation Protocols for PEMFC MEA with PtCo/C Catalyst (PtCo/C 촉매를 사용한 PEMFC MEA의 활성화 프로토콜 비교)

  • GISEONG LEE;HYEON SEUNG JUNG;JINHO HYUN;CHANHO PAK
    • Transactions of the Korean hydrogen and new energy society
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    • v.34 no.2
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    • pp.178-186
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    • 2023
  • Three activation methods (constant voltage, current cycling, and hydrogen pumping) were applied to investigate the effects on the performance of the membrane electrode assembly (MEA) loaded with PtCo/C catalyst. The current cycling protocol took the shortest time to activate the MEA, while the performance after activation was the worst among the all activation methods. The constant voltage method took a moderate activation time and exhibited the best performance after activation. The hydrogen pumping protocol took the longest time to activate the MEA with moderate performance after activation. According to the distribution of relaxation time analysis, the improved performance after the activation mainly comes from the decrease of charge transfer resistance rather than the ionic resistance in the cathode catalyst layer, which suggests that the existence of water on the electrode is the key factor for activation.

The Performance Evaluation of Parallel and Single Structure MCMA-MDD Adaptive Equalizer for 16-QAM Signal (16-QAM 신호에대한 병렬 구조와 단일 구조를 갖는 MCMA-MDD 적응 등화기의 성능 평가)

  • Lim, Seung-Gag
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.12 no.4
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    • pp.15-22
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    • 2012
  • This paper deals with the performance comparison and evaluation of blind adaptive equalizer, the PMCMA-MDD and DW-MCMA, that is used for compensation of the amplitude and phase distortion which occurs in the time dispersive channel. Basically, these algorithms are modification of MCMA cost function in order to obtain the fast convergence speed and reduced residual isi by taking the parallel and serial double structured and the combination of the concept of RCA for the updating the tap coefficient. We implements the algorithm of it and compare the recovered constellation, residual isi, MSE characteristics curve and SER in the signal to noise ratio given the time dispersive channel. As a result of simulation, the PMCMA-MDD has a good in recovered constellation than DW-MCMA. But in the SER, the DW-MCMA has a good than PMCMA-MDD.

The Performance Comparison of MMA and S-MMA Adaptive Equalization Algorithm for QAM Signal (QAM 신호에대한 MMA와 S-MMA 적응 등화 알고리즘의 성능 비교)

  • Kang, Dae-Soo;Lim, Seung-Gag
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.13 no.1
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    • pp.19-26
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    • 2013
  • This paper deals with the performance comparison of blind adaptive equalization algorithm, the MMA and S-MMA, that is used for compensation of the amplitude and phase distortion simultaneously which occurs in the time dispersive channel. The present CMA algorithm is possible to compensates the amplitude only, but not in phase, so it needs to the another additional circuit for compensating the phase. In order to overcoming the abovemensioned shorthand, the improved cost function is applied to the MMA algorithm. In MMA algorithm, the error is consists of the dispersion constant only, but in S-MMA, the error is consists of the dispersion constant considering the output of decision device (sliced symbol) in order to updating the tap coefficients. By using the two kind error signal, the adaptive equalization algorithm has different performance. In this paper, we compare to the adaptive equalization algorithm performance by using the recovered constellation, residual isi, MD (Maximum Distortion) and SER as a index when the transmitting signal is 16 and 64-QAM and then passing through the same communication channel. As a result of simulation, the S-MMA can improving the Roburstness in SER performance compared to the MMA in the high order QAM signal.

Wall Superheat Effect on Single Bubble Growth During Nucleate Boiling at Saturated Pool (풀 핵비등시 단일 기포 성장에 대한 벽면 과열도의 영향에 관한 연구)

  • Kim Jeong bae;Lee Han Choon;Kim Moo Hwan
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.5 s.236
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    • pp.633-642
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    • 2005
  • Nucleate pool boiling experiments for R11 under a constant wall temperature condition were carried out. A microscale heater array was used for the heating and the measurement of high temporal and spatial resolution by the Wheatstone bridge circuit. Very sensitive heat flow rate data were obtained by the control for the surface condition with high time resolution. The measured heat flow rate shows a discernable peak at the initial growth stage and reaches an almost constant value. In the thermal growth region, bubble shows a growth proportional to $t^{\frac{1}{5}}$. The bubble growth behavior is analyzed with a dimensionless parameter to compare with the previous results in the same scale. As the wall superheat increases, the departure diameter and the departure time increase, and the waiting time decreases. But the asymptotic growth rate is not affected by the wall superheat change. The effect of the wall superheat is resolved into the suggested growth equation. Dimensionless parameters of time and bubble radius characterize the thermal growth behavior well, irrespective of wall condition. The comparison between the result of this study and the previous results shows a good agreement at the thermal growth region. The quantitative analysis for the heat transfer mechanism is conducted with the measured heat flow rate behavior and the bubble growth behavior. The required heat flow rate for the volume change of the observed bubble is about twice as much as the instantaneous heat flow rate supplied from the wall.

Development of Integrated Simulator for AC Traction Power Supply System (윈도우즈 기반의 교류 전기철도 급전시스템 통합 시뮬레이터 개발)

  • Kim, Joo-Rak;Kim, Jung-Hoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.1
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    • pp.76-81
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    • 2010
  • This paper describes the development of integrated simulator with GUI(Graphic User Interface) for traction power supply system. This simulator consists of a lot of calculation modules such as TPS, train time schedule, line constant, and power supply system analysis. Each module has input and output structure respectively. The algorithms of all modules have confirmed the validity to comparison with field test that is performed on both high speed railway line and conventional line.

An Analysis of Surface irrigation's Hydraulic Characteristics at a Paddy Field Using a Two-Dimensional Numerical Model (2차원 유한체적 수치모형을 이용한 논의 지표관개 수리특성 분석)

  • Park, Seung-Woo;Park, Jong-Min;Kang, Min-Goo
    • Journal of The Korean Society of Agricultural Engineers
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    • v.46 no.4
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    • pp.3-11
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    • 2004
  • A finite volume model is developed to simulate the surface irrigation at a paddy field. The model's capabilities are validated through comparison with the simulafed results and the observed data obtained by various experimental tests, and the simulated results are in good agreement with the observed pending depth. The result of surface irrigation simulation shows that the longer the paddy field's the length of long-sided becomes, the longer the advance and storage time is taken. To analyze surface irrigation performance with variable inflow rate, three patterns of flow variation-constant rate, initially high then low, and initially low then high-were studied. The results show that at the pattern with initially high followed by low during the latter half of the irrigation the advance time is shortest, but the pending depth of irrigation completion and irrigation effiency are the little difference between irrigation patterns.

To Determine the Characteristic Polynomial Coefficients Based On the Transient Response

  • Haeri, Mohammad;Tavazoei, Mohammad Saleh
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.11-15
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    • 2005
  • This paper presents a method to determine the characteristic polynomial of a closed loop all-pole system in order to obtain desired transient response in terms of the overshoot and speed (rising/settling time). The method adjusts the overshoot by doing some changes in the characteristic ratios of the Bessel-Thompson filter. The closed loop speediness is then tuned by suitable choice of the generalized time constant. Simulation results are presented to evaluate the achievements and make comparison with those of a similar method.

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Comparison Studies of PSO Techniques for PV System Allocation Problem (PV 시스템 계획 문제에 대한 PSO 기법들의 비교 연구)

  • Diolata, Ryan;Song, Hwa-Chang;Joo, Young-Hoon
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.482-483
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    • 2008
  • This paper compares particle swarm optimization techniques for PV allocation planning problem in power systems. PV allocation planning problem is formulated as a mixed-integer nonlinear problem. Five variants of PSO techniques are investigated for the applicability on the PV allocation problem. Namely, PSO with constant inertia weight approach (PSO-CIW), PSO with time varying inertia weight (PSO-TVIW), PSO with random inertia weight (PSO-RIW), PSO with constriction factor (PSO-CF) and PSO with time varying acceleration coefficients (PSO-TVAC).

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