• Title/Summary/Keyword: near optimal

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Cross Layer Optimal Design with Guaranteed Reliability under Rayleigh block fading channels

  • Chen, Xue;Hu, Yanling;Liu, Anfeng;Chen, Zhigang
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.7 no.12
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    • pp.3071-3095
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    • 2013
  • Configuring optimization of wireless sensor networks, which can improve the network performance such as utilization efficiency and network lifetime with minimal energy, has received considerable attention in recent years. In this paper, a cross layer optimal approach is proposed for multi-source linear network and grid network under Rayleigh block-fading channels, which not only achieves an optimal utility but also guarantees the end-to-end reliability. Specifically, in this paper, we first strictly present the optimization method for optimal nodal number $N^*$, nodal placement $d^*$ and nodal transmission structure $p^*$ under constraints of minimum total energy consumption and minimum unit data transmitting energy consumption. Then, based on the facts that nodal energy consumption is higher for those nodes near the sink and those nodes far from the sink may have remaining energy, a cross layer optimal design is proposed to achieve balanced network energy consumption. The design adopts lower reliability requirement and shorter transmission distance for nodes near the sink, and adopts higher reliability requirement and farther transmission distance for nodes far from the sink, the solvability conditions is given as well. In the end, both the theoretical analysis and experimental results for performance evaluation show that the optimal design indeed can improve the network lifetime by 20-50%, network utility by 20% and guarantee desire level of reliability.

Air-Gap Control Using Optimal PID Controller for SIL-Based Near-Field Recording System (SIL 기반 근접장 기록 시스템의 간극 제어를 위한 최적화된 PID 제어 알고리즘 성능평가)

  • Shin, Won-Ho;Kim, Jung-Gon;Park, No-Cheol;Yang,, Hyun-Seok;Park, Young-Pil;Park, Kyoung-Su
    • Transactions of the Society of Information Storage Systems
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    • v.5 no.1
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    • pp.41-46
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    • 2009
  • In SIL-based NFR servo systems, the residual error and the overshoot that are occurred in the process of the modes-witching servo which consists of approach, gap-control modes, and safety mode are reduced by using PID controller. However, the design method of conventional PID controller is not sufficient for the stable air gap control system. Therefore, the optimal PID controller using LQR manner is more useful to find the designed parameters of PID controller. In this paper, we show that the performance of the optimal PID controller is better than that of the lead-lag controller.

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A Bayesian Approach to Linear Calibration Design Problem

  • Kim, Sung-Chul
    • Journal of the Korean Operations Research and Management Science Society
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    • v.20 no.3
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    • pp.105-122
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    • 1995
  • Based on linear models, the inference about the true measurement x$_{f}$ and the optimal designs x (nx1) for the calibration experiments are considered via Baysian statistical decision analysis. The posterior distribution of x$_{f}$ given the observation y$_{f}$ (qxl) and the calibration experiment is obtained with normal priors for x$_{f}$ and for themodel parameters (.alpha., .betha.). This posterior distribution is not in the form of any known distributions, which leads to the use of a numerical integration or an approximation for the calculation of the overall expected loss. The general structure of the expected loss function is characterized in the form of a conjecture. A near-optimal design is obtained through the approximation nof the conditional covariance matrix of the joint distribution of (x$_{f}$ , y$_{f}$ $^{T}$ )$^{T}$ . Numerical results for the univariate case are given to demonstrate the conjecture and to evaluate the approximation.n.

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Optimal Design of NFR Coarse Actuator (근접장 광기록 장치용 조동 구동기의 최적 설계)

  • 정재화;이성규;김기현;권대갑
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.592-596
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    • 2001
  • Near field technology makes it possible to overcome the diffraction limit of laser beam and create the small spot. Because of the small spot size, the pit size and track pitch can be decreased. So the high performance actuator is needed for near field recording system. And the light mass and the small form factor are also important properties of the NFR actuator in order to be used for hand held device. The purpose of this paper is the optimal design of the NFR coarse actuator to maximize actuating force. The structure of NFR coarse actuator is the same as HDD VCM actuator. The permeance method is used for modeling of the coarse actuator. The optimal result and the FEM simulation result are presented.

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Dynamic Optimal Design of Continuous Beams (연속보의 동적 최적설계에 관한 연구)

  • 이병구;오상진;모정만
    • Computational Structural Engineering
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    • v.10 no.2
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    • pp.233-242
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    • 1997
  • The main purpose of this paper is to investigate the dynamic optimal design of continuous beams. The computer-aided optimization technique is used to obtain the near-optimal parameters of continuous beam. The computer program is developed to obtain the natural frequency parameters and the forced vibration responses to a transit point load for the continuous beam with variable support spacing, mass and stiffness. The model test data is in good agreement with the computer calculation, which serves to validate the mathematical analysis. The optimization function to describe the design efficiency is defined as a linear combination of four dimensionless span characteristics; the maximum dynamic stress; the stress difference between span segments; the rms deflection under the transit point load; and the total span mass. Studies of three span beams show that the beam with near-optimal parameters can improve design efficiency when compared to a uniform beam with even spacing of the same total span length.

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Shipyard Spatial Scheduling Solution using Genetic Algorithms

  • Yoon Duck Young;Ranjan Varghese
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2004.11a
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    • pp.35-39
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    • 2004
  • In a shipyard, there exist various critical decision making components pertaining to various production hindrances. The most prominent one is best-fit spatial arrangement for the minimal spatial occupancy with better pick-ability for the erection of the ship in the dock. During the present research, a concept have been conceived to evade the gap between the identification oj inter-relationships among a set of blocks to be included on a pre-erection area, and a detailed graphical layout of their positions, is called an Optimal Block Relationship Diagram A research has been performed on generation of optimal (or near Optimal) that is, with minimal scrap area. An effort has been made in the generation of optimal (or near-optimal) Optimal Block Relationship Diagram with the Goldberg's Genetic Algorithms with a representation and a set of operators are 'trained' specifically for this application. The expected result to date predicts very good solutions to test problems involving innumerable different blocks to place. The suggested algorithm could accept input from an erection sequence generator program which assists the user in defining the nature and strength of the relationships among blocks, and could produce input suitable for use in a detailed layout stage.

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Tight Lower Bound of Optimal Non-Coherent Detection for FSK Modulated AF Cooperative Communications in Rayleigh Fading Channels

  • Tian, Jian;Zhang, Qi;Yu, Fengqi
    • Journal of Communications and Networks
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    • v.13 no.4
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    • pp.313-318
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    • 2011
  • When wireless channels undergo fast fading, non-coherent frequency shift keying (FSK) (de)modulation schemes may be considered for amplify-and-forward (AF) cooperative communications. In this paper, we derive the bit-error-rate performance of partial non-coherent receiver as a lower bound of the optimal non-coherent receiver for FSK modulated AF cooperative communications. From the simulation and analytical results, it is found that the derived lower bound is very closed to simulation results. This result shows that knowing partial channel state information may not improve system performance significantly. On the other hand, conventional optimal non-coherent receiver involves complicated integration operation. To address the above complexity issue, we also propose a near optimal non-coherent receiver which does not involve integration operation. Simulation results have shown that the performance gap between the proposed near optimal receiver and the optimal receiver is small.

Development of the Algorithm for Optimizing Wavelength Selection in Multiple Linear Regression

  • Hoeil Chung
    • Near Infrared Analysis
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    • v.1 no.1
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    • pp.1-7
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    • 2000
  • A convenient algorithm for optimizing wavelength selection in multiple linear regression (MLR) has been developed. MOP (MLP Optimization Program) has been developed to test all possible MLR calibration models in a given spectral range and finally find an optimal MLR model with external validation capability. MOP generates all calibration models from all possible combinations of wavelength, and simultaneously calculates SEC (Standard Error of Calibration) and SEV (Standard Error of Validation) by predicting samples in a validation data set. Finally, with determined SEC and SEV, it calculates another parameter called SAD (Sum of SEC, SEV, and Absolute Difference between SEC and SEV: sum(SEC+SEV+Abs(SEC-SEV)). SAD is an useful parameter to find an optimal calibration model without over-fitting by simultaneously evaluating SEC, SEV, and difference of error between calibration and validation. The calibration model corresponding to the smallest SAD value is chosen as an optimum because the errors in both calibration and validation are minimal as well as similar in scale. To evaluate the capability of MOP, the determination of benzene content in unleaded gasoline has been examined. MOP successfully found the optimal calibration model and showed the better calibration and independent prediction performance compared to conventional MLR calibration.

NoCOM: Near-Optimal Cell Outage Management for Guaranteeing User QoS (사용자 서비스 품질 보장을 위한 근접-최적 셀 아웃티지 관리 기법)

  • Lee, Kisong;Lee, Howon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.4
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    • pp.794-799
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    • 2015
  • To manage cell outage problem in indoor wireless communication systems, we should resolve the problem of abrupt network failure quickly. In this paper, we propose a near-optimal cell outage management (NoCOM) scheme to support seamless services to users. In consideration of system throughput, user fairness, and the guarantee of QoS simultaneously, the NoCOM scheme finds the solution of subchannel and power allocations using a non-convex optimization technique and allocates radio resources to users iteratively. Through intensive simulations, we verify the outstanding performances of the proposed NoCOM scheme with respect to the average cell capacity, user fairness, and computational complexity.