• Title/Summary/Keyword: Optimizing Parameters

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Development and Application of TFT-LCD Pixel Design Tool (PDAST) (TFT-LCD 화소 설계 도구(PDAST)의 개발과 응용)

  • Lee, Yeong-Sam;Gwak, Ji-Hun;Choe, Jong-Seon
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.48 no.6
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    • pp.416-428
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    • 1999
  • A user-interactive pixel design tool for high-quality TFT-LCDs is realized and used to explore the sensitivity of the various array and device parameters for optimizing pixel design. In this tool, the Thompson cable equation and gradual-channel approximation were used for the gate time delay and TFT current modeling respectively. With this tool, each capacitance element, and TFT and array dimensions can be optimized under given design specifications. The electrical characteristics such ascharging ratio, gate time delay, pixel voltage level-shift, and holding ratio can be analyzed. The sensitivity analysis of those design parameters were executed and presented.

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Modeling methods used in bioenergy production processes: A review

  • Akroum, Hamza;Akroum-Amrouche, Dahbia;Aibeche, Abderrezak
    • Advances in Computational Design
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    • v.5 no.3
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    • pp.323-347
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    • 2020
  • The enhancements of bioenergy production effectiveness require the comprehensively experimental study of several parameters affecting these bioprocesses. The interpretation of the obtained experimental results and the estimation of optimum yield are extremely complicated such as misinterpreting the results of an experiment. The use of mathematical modeling and statistical experimental designs can consistently supply the predictions of the potential yield and the identification of defining parameters and also the understanding of key relationships between factors and responses. This paper summarizes several mathematical models used to achieve an adequate overall and maximal production yield and rate, to screen, to optimize, to identify, to describe and to provide useful information for the effect of several factors on bioenergy production processes. The usefulness, the validity and, the feasibility of each strategy for studying and optimizing the bioenergy-producing processes were discussed and confirmed by the good correlation between predicted and measured values.

An Adaptive Companding Scheme for Peak-to-average Power Ratio Reduction in OFDM Systems

  • Mazahir, Sana;Sheikh, Shahzad Amin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.12
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    • pp.4872-4891
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    • 2015
  • Orthogonal frequency division multiplexing (OFDM) signals suffer from the problem of high peak-to-average power ratio (PAPR), which complicates the design of analog front-end of the system. Companding is a well-known PAPR reduction technique that involves transforming signal amplitudes using a deterministic function. OFDM signal amplitude, on average, is Rayleigh distributed but the distribution can vary significantly from symbol to symbol, especially when constellation size increases. In this paper, a new adaptive companding scheme is proposed along with its design methodology aiming at optimizing the compander performance by accommodating this variation in its design. This is achieved by designing compander parameters separately for statistically dissimilar symbols in OFDM waveform and making the compander select from these parameters, during run-time, according to the features of input symbols.

Communication-Theoretic Analysis of Capture-Based Networks

  • Nguyen, Gam D.;Wieselthier, Jeffrey E.;Ephremides, Anthony
    • Journal of Communications and Networks
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    • v.14 no.3
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    • pp.243-251
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    • 2012
  • Under the power-based capture model, a transmission is successfully received at the destination, even in the presence of other transmissions and background noise, if the received signal-to-interference-plus-noise ratio exceeds a capture threshold. We evaluate the spectral efficiency of simple multi-user channels by combining the basic capture model with a communication-theoretic model. The result is a more refined capture model that incorporates key system design parameters (such as achievable bit rate, target bit error rate, channel bandwidth, and modulation signal constellations) that are absent from the basic capture model. The relationships among these parameters can serve as a tool for optimizing the network performance.

Optimal Condition Determination of Glass Sealing Parameters using the Design of Experiment (실험계획법을 이용한 유리접합의 최적 공정 조건 결정)

  • Lee, Jong-Gon;Jeon, Euy-Sik
    • Proceedings of the KWS Conference
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    • 2009.11a
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    • pp.78-78
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    • 2009
  • Glass sealing method is used glass bond as called frit in LCD, PDP process. but new sealing method is need to consider the endurance and economy. This paper present the new glass sealing method using high density gas torch in the furnace and process variable are defined by experiment. Taguchi Robust Experimental Design methods were applied for optimizing these four main processing parameters.

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A Study on Performance Optimization of a Hydraulic Breaker (범용 유압 브레이커의 성능 최적화를 위한 연구)

  • Shin, Dae-Young;Kwon, Ki-Beom
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.6
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    • pp.677-682
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    • 2011
  • In this study, a simulation model developed for a hydraulic breaker is verified through comparison of simulation results to the experimental results. For performance optimization, the design parameters are selected based on the physical parameters of the equipment for ease of modification. Also a factorial experiment and regression analysis were conducted to observe the effect of each parameter on the performance of the hydraulic breaker. As a result, a method for optimizing the performance of a hydraulic breaker is proposed.

Advance Neuro-Fuzzy Modeling Using a New Clustering Algorithm (새로운 클러스터링 알고리듬을 적용한 향상된 뉴로-퍼지 모델링)

  • 김승석;김성수;유정웅
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.53 no.7
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    • pp.536-543
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    • 2004
  • In this paper, we proposed a new method of modeling a neuro-fuzzy system using a hybrid clustering algorithm. The initial parameters and the number of clusters of the proposed system are optimally chosen simultaneously with respect to the process of regression, which is a unique characteristics of the proposed system. The proposed algorithm presented in this work improves the overall performance of the proposed a neuro-fuzzy system by choosing a proper number of clusters adaptively according the characteristics of given data. The process of clustering is performed by deciding on the number of classes, which yields the property of convergence of the system. In experiments, the superiority of the proposed neuro-fuzzy system is demonstrated, especially the process of optimizing parameters and clustering of learning speed.

Optimizing the Net Gain of a Raman-EDFA Hybrid Optical Amplifier using a Genetic Algorithm

  • Singh, Simranjit;Kaler, Rajinder Singh
    • Journal of the Optical Society of Korea
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    • v.18 no.5
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    • pp.442-448
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    • 2014
  • For the first time, a novel analytical model of the net gain for a Raman-EDFA hybrid optical amplifier (HOA) is proposed and its various parameters optimized using a genetic algorithm. Our method has been shown to be robust in the simultaneous analysis of multiple parameters (Raman length, EDFA length, and pump powers) to obtain large gain. The optimized HOA is further investigated at the system level for the scenario of a 50-channel DWDM system with 0.2-nm channel spacing. With an optimized HOA, a flat gain of >17 dB is obtained over the effective ITU-T wavelength grid with a variation of less than 1.5 dB, without using any gain-flattening technique. The obtained noise figure is also the lowest value ever reported for a Raman-EDFA HOA at reduced channel spacing.

Development of a computer aided program for slipforming operations incorporating maturity approach

  • Hossain, K.M.A.;Anagnostopoulos, C.;Lachemi, M.
    • Computers and Concrete
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    • v.3 no.2_3
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    • pp.177-195
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    • 2006
  • Slipforming is a construction method in which the forms move continuously during the placement of concrete. This paper presents the development of a computer aided program designated as "CADSLIPFORM" for slipforming operations. The program incorporates maturity methods for the prediction of initial setting times of slipform concrete layers using laboratory data (time-temperature histories and setting times of concrete mixtures at different temperatures) and generates slipform mock-up times. The performance of CADSLIPFORM is validated by comparing simulated mock-up times with those estimated in the field through conventional hard front by rod (R) method. Moreover, the program versatility is demonstrated by illustrating mock-up simulations for different cases with variable slipform parameters such as: number and thickness of concrete layers, concrete temperature (simulating variable setting times) and slipform speed. The program also incorporates the choice of Freiesleben Hansen & Pederson (FHP) and Carino & Tank (CT) maturity functions. CADSLIPFORM can assist user to develop reliable schedule of slipforming operation suitable for a specific project by optimizing various slipform parameters.

A Novel Image Classification Method for Content-based Image Retrieval via a Hybrid Genetic Algorithm and Support Vector Machine Approach

  • Seo, Kwang-Kyu
    • Journal of the Semiconductor & Display Technology
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    • v.10 no.3
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    • pp.75-81
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    • 2011
  • This paper presents a novel method for image classification based on a hybrid genetic algorithm (GA) and support vector machine (SVM) approach which can significantly improve the classification performance for content-based image retrieval (CBIR). Though SVM has been widely applied to CBIR, it has some problems such as the kernel parameters setting and feature subset selection of SVM which impact the classification accuracy in the learning process. This study aims at simultaneously optimizing the parameters of SVM and feature subset without degrading the classification accuracy of SVM using GA for CBIR. Using the hybrid GA and SVM model, we can classify more images in the database effectively. Experiments were carried out on a large-size database of images and experiment results show that the classification accuracy of conventional SVM may be improved significantly by using the proposed model. We also found that the proposed model outperformed all the other models such as neural network and typical SVM models.