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4th International Conference on Wireless Communications, Networking and Mobile Computing

作者： Wang, Ning Wang, Lu Yang, Nannan Beijing Univ Posts & Telecommun Econ & Management Sch Beijing 100088 Peoples R China Beijing Univ Technol Coll Econ & Management Beijing Peoples R China Beijing Inst Fashion Technol Business Sch Beijing Peoples R China

ISBN: (纸本)9781424421077

In order to effectively avoid risks that might result in loss of failure in software development process, based on the experiences of software development and project management, this paper identifies 4 potential risk factors specific to software development projects which are integrated with 6 stages in software development process, and proposes a non-linear programming model to optimize funds allocation to reduce the risks. The paper provides an example to validate the effectiveness of the model.

关键词： software project development risk factors funds allocation non-linear programming K-T Condition

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Power-aware scheduling of preemptable jobs on identical parallel processors to meet deadlines

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EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 2012年第1期218卷 68-75页

作者： Rozycki, R. Weglarz, J. Poznan Univ Tech Inst Comp Sci PL-60965 Poznan Poland

This paper deals with a power-aware scheduling of preemptable independent jobs on identical parallel processors where ready time for each job is given and its completion time has to meet a given deadline. Jobs are described by (different) continuous, strictly concave functions relating their processing speeds at a time to the amount of power allotted at the moment. Power is a continuous, doubly constrained resource, i.e. both: its availability at each time instant and consumption over scheduling horizon are constrained. A methodology based on properties of minimum-length schedules is utilized to determine the existence of a feasible schedule for given amounts of energy and power. The question about minimum levels of power and energy ensuring the existence of a feasible schedule for a given set of jobs is also studied. (C) 2011 Elsevier B.V. All rights reserved.

关键词： Power-aware computing Preemptable jobs Ready times Deadlines non-linear programming

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The economic value of improved agrometeorological information to irrigators amid climate variability

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INTERNATIONAL JOURNAL OF CLIMATOLOGY 2012年第4期32卷 567-581页

作者： Mushtaq, Shahbaz Chen, Charlie Hafeez, Mohsin Maroulis, Jerry Gabriel, Hamza Univ So Queensland Australian Ctr Sustainable Catchments Toowoomba Qld 4350 Australia Charles Sturt Univ Int Ctr Water Food Secur Wagga Wagga NSW 2678 Australia CSIRO Black Mt CSIRO Canberra ACT Australia

In Australia, climate variability and the predicted impact of climate change help in making seasonal rainfall less predictable and seasonal irrigation supplies more uncertain, eroding agricultural production prospects and profitability. Water allocation forecasts have economic value to irrigators for making informed cropping decisions. This study estimated the economic value of improved irrigation allocation forecasts in the Coleambally irrigation area (CIA) in southeastern Australia using a non-linear programming model. The model uses production and profit functions to estimate yield and gross margins for various water allocation levels rather than using given crop yields and gross margins. The model also captures the tactical response of improved cropping decisions made by irrigators based on water allocation announcements throughout the irrigation season. Tactical responses include changing the winter crop combinations, abandoning irrigation for a percentage of the summer crops, temporary purchase or sale of water, and deficit irrigation. The estimated economic benefit of improved seasonal water allocation forecasts to the CIA irrigators ranges from AU$1.33 ha(-1) to AU$9.58 ha(-1) (AU$1 = US$0.77). The economic analysis of water allocation forecasts shows that the potential total gross margin for the irrigators at the 100% allocation level was AU$47.6 m, assuming accurate forecast of the end-of-season allocations. A more realistic scenario generates a forecast value of AU$8.9 million reduction in the gross margin (pessimistic water allocation outlook) and AU$1.60 million in the forgone gross margin (optimistic water allocation outlook) for only 5% variation in outlook above or below the actual allocation level of 60%. This suggests that losses far exceed when water allocations are over-estimated by irrigators, as resources and inputs could be overly committed to execute the less-informed cropping plans. The knowledge benefits from forecasts are far greater at th

关键词： water allocation water policy forecasting economic value non-linear programming Australia

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Design optimization with chaos embedded great deluge algorithm

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APPLIED SOFT COMPUTING 2012年第3期12卷 1055-1067页

作者： Baykasoglu, Adil Dokuz Eylul Univ Fac Engn Dept Ind Engn TR-35160 Izmir Turkey

In this paper, the great deluge algorithm (GDA), which has not been previously used in constrained mechanical design optimization problems is employed to solve several design optimization problems selected from the literature. The GDA algorithm needs only one basic parameter to setup, which makes it very attractive for solving optimization problems. First time in this paper, an attempt is made to see whether it is possible to enhance the performance of a very simple algorithm like GDA to solve complex constrained non-linear design optimization problems by embedding chaotic maps in its neighborhood generation mechanism. Eight different chaotic maps are tested and compared in this paper. It is observed that chaotic maps can considerably improve the performance of GDA and enables it to find the best possible solutions for the studied problems. (C) 2011 Elsevier B.V. All rights reserved.

关键词： Great deluge algorithm Chaotic maps Design optimization non-linear programming

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A breakpoint search approach for convex resource allocation problems with bounded variables

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OPTIMIZATION LETTERS 2012年第4期6卷 629-640页

作者： De Waegenaere, Anja Wielhouwer, Jacco L. Tilburg Univ Ctr Econ Res NL-5000 LE Tilburg Netherlands Tilburg Univ Dept Econometr & Operat Res NL-5000 LE Tilburg Netherlands Vrije Univ Amsterdam Dept Accounting Fac Econ NL-1081 HV Amsterdam Netherlands

We present an efficient approach to solve resource allocation problems with a single resource, a convex separable objective function, a convex separable resource-usage constraint, and variables that are bounded below and above. Through a combination of function evaluations and median searches, information on whether or not the upper- and lowerbounds are binding is obtained. Once this information is available for all upper and lower bounds, it remains to determine the optimum of a smaller problem with unbounded variables. This can be done through a multiplier search procedure. The information gathered allows for alternative approaches for the multiplier search which can reduce the complexity of this procedure.

关键词： Resource allocation Multiplier search non-linear programming Pegging

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Energy-efficient spectrum sensing by optimal periodic scheduling in cognitive radio networks

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IET COMMUNICATIONS 2012年第6期6卷 676-684页

作者： Deng, R. He, S. Chen, J. Jia, J. Zhuang, W. Sun, Y. Zhejiang Univ State Key Lab Ind Control Technol Hangzhou 310027 Zhejiang Peoples R China Univ Waterloo Dept Elect & Comp Engn Waterloo ON N2L 3G1 Canada

Nowadays, with the dramatically increased penetration of wireless access, the conflict between spectrum scarcity and under-utilisation is becoming more and more aggravating. A promising technology to tackle such challenge is cognitive radio, of which spectrum sensing is one of the most important functionalities. In this study, the authors consider an essential problem of energy-efficient spectrum sensing in cognitive radio networks. Although most existing works of spectrum sensing mainly focus on determining an optimal sensing time to maximise the detection probability and/or to minimise the false alarm probability, our problem of how to schedule the power-constrained sensor is much more challenging, because of the trade-off among interests of the primary user, secondary user and sensor. The authors formulate it as a non-linear optimisation problem to maximise the sensor lifetime, with necessary constraints of quality and delay of spectrum sensing, and throughput for performance guarantee of primary and secondary users. Moreover, the authors incorporate the distribution information of channel occupancy/vacancy durations into the problem to yield a desirable solution. They propose a novel framework to obtain the optimal energy-efficient periodic scheduling by adopting both non-linear programming and linear programming. Extensive simulation results are provided to validate our theoretical analysis.

关键词： Radio access systems energy-efficient spectrum sensing non-linear programming false alarm probability radio access networks optimal periodic scheduling primary users power-constrained sensor radio spectrum management cognitive radio energy-efficient periodic scheduling cognitive radio networks non-linear optimisation problem wireless access scheduling secondary users

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A generalized compensation theory for active filters based on mathematical optimization in ABC frame

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ELECTRIC POWER SYSTEMS RESEARCH 2012年 90卷 1-10页

作者： Garces, Alejandro Molinas, Marta Rodriguez, Pedro Norwegian Univ Sci & Technol N-7034 Trondheim Norway Univ Tecnol Pereira La Julita Pereira Colombia Univ Politecn Cataluna Terrassa 08222 Spain

This paper presents a generalization of the ABC compensation theory based on mathematical optimization which integrates the neutral losses into the optimization model. The classical ABC theory is shown to be a particular case of the presented generalized compensation approach. The main contribution of this paper is the generalization of the ABC theory considering conflictive objectives which include among them the minimization of the network losses. The work presented here takes. into account not only conventional balanced and pure sinusoidal voltage source but also unbalances and harmonic distortions on the voltage. Four different compensation objectives are studied: invariant instantaneous power, constant power, unity power factor, and pure sinusoidal current. Through these four cases, the flexibility and simplicity of implementation of this approach is demonstrated. In addition, the proposed compensation strategy optimizes the line currents and therefore minimizes the network losses. The main contributions A simulation study which considers the switching effect, the control of the DC link and the size of the shunt compensator is presented. Experimental tests are carried out to verify the theory. (C) 2012 Elsevier B.V. All rights reserved.

关键词： Reactive power compensation ABC theory Optimization non-linear programming Lagrange multipliers Active filters

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Identifying optimal cleaning cycles for heat exchangers subject to fouling and ageing

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APPLIED ENERGY 2012年第1期89卷 60-66页

作者： Pogiatzis, Thomas Ishiyama, Edward M. Paterson, William R. Vassiliadis, Vassilios S. Wilson, D. Ian Dept Chem Engn & Biotechnol Cambridge CB2 3RA England

Fouling of heat exchangers causes reduced heat transfer and other penalties. Regular cleaning represents one widely used fouling mitigation strategy, where the schedule of cleaning actions can be optimised to minimise the cost of fouling. This paper investigates, for the first time, the situation where there are two cleaning methods available so that the mode of cleaning has to be selected as well as the cleaning interval. Ageing is assumed to convert the initial deposit, labelled 'gel', into a harder and more conductive form, labelled 'coke', which cannot be removed by one of the cleaning methods. The second method can remove both the gel layer and the coke layer, but costs more and requires the unit to be off-line longer for cleaning. Experimental data demonstrating the effects of ageing are presented. The industrial application is the comparison of cleaning-in-place methods with off-line mechanical cleaning. A process model is constructed for an isolated counter-current heat exchanger subject to fouling, where ageing is described by a simple two-layer model. Solutions generated by an NLP-based approach prove to be superior to a simpler heuristic. A series of case studies demonstrate that combinations of chemical and mechanical cleaning can be superior to mechanical cleaning alone for certain combinations of parameters. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： Ageing Cleaning Fouling non-linear programming Optimisation Scheduling

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Fuzzy Bayesian system reliability assessment based on prior two-parameter exponential distribution under different loss functions

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SOFTWARE TESTING VERIFICATION & RELIABILITY 2012年第3期22卷 203-217页

作者： Gholizadeh, Ramin Shirazi, Aliakbar Mastani Gildeh, Bahram Sadeghpour Islamic Azad Univ Iran Dept Stat Fac Sci Mashhad Branch Mashhad Iran Islamic Azad Univ Fars Sci & Res Branch Shiraz Iran Univ Mazandaran Dept Stat Fac Basic Sci Babol Sar Iran

The fuzzy Bayesian system reliability assessment based on prior two-parameter exponential distribution under squared error symmetric loss function and precautionary asymmetric loss function is proposed in this paper. In order to apply the Bayesian approach, the fuzzy parameters are assumed as fuzzy random variables with fuzzy prior distributions. Because the goal of the paper is to obtain fuzzy Bayes point estimators of system reliability assessment, prior distributions of location-scale family has been changed to scale family with change variable. On the other hand, also the computational procedures to evaluate the membership degree of any given Bayes point estimate of system reliability have been provided. In order to achieve this purpose, we transform the original problem into a non-linear programming problem. This non-linear programming problem is then divided into four sub-problems for the purpose of simplifying computation. Finally, the sub-problems can be solved by using any commercial optimizers, e.g. GAMS or LINGO. Copyright (c) 2010 John Wiley & Sons, Ltd.

关键词： Bayes point estimators confidence degree fuzzy real numbers non-linear programming system reliability two-parameter exponential distribution precautionary loss function

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Optimization of lift gas allocation in a gas lifted oil field as non-linear optimization problem

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MODELING IDENTIFICATION AND CONTROL 2012年第1期33卷 13-25页

作者： Sharma, Roshan Fjalestad, Kjetil Glemmestad, Bjorn Telemark Univ Coll Dept Elect Informat & Cubernet Porsgrunn Norway Statoil Res Ctr Porsgrunn Norway

Proper allocation and distribution of lift gas is necessary for maximizing total oil production from a field with gas lifted oil wells. When the supply of the lift gas is limited, the total available gas should be optimally distributed among the oil wells of the field such that the total production of oil from the field is maximized. This paper describes a non-linear optimization problem with constraints associated with the optimal distribution of the lift gas. A non-linear objective function is developed using a simple dynamic model of the oil field where the decision variables represent the lift gas flow rate set points of each oil well of the field. The lift gas optimization problem is solved using the 'fmincon' solver found in MATLAB. As an alternative and for verification, hill climbing method is utilized for solving the optimization problem. Using both of these methods, it has been shown that after optimization, the total oil production is increased by about 4%. For multiple oil wells sharing lift gas from a common source, a cascade control strategy along with a nonlinear steady state optimizer behaves as a self-optimizing control structure when the total supply of lift gas is assumed to be the only input disturbance present in the process. Simulation results show that repeated optimization performed after the first time optimization under the presence of the input disturbance has no effect in the total oil production.

关键词： Optimization non-linear programming cascade control structure gas lifted oil well hill climbing self-optimization

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