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Modelling the mobile target covering problem using flying drones

OPTIMIZATION LETTERS 2016年第5期10卷 1021-1052页

作者： Pugliese, Luigi Di Puglia Guerriero, Francesca Zorbas, Dimitrios Razafindralambo, Tahiry Univ Calabria Dept Mech Energy & Management Engn I-87036 Arcavacata Di Rende CS Italy Inria Lille Nord Europe Villeneuve Dascq France

This paper addresses the mobile targets covering problem by using unmanned aerial vehicles (UAVs). It is assumed that each UAV has a limited initial energy and the energy consumption is related to the UAV's altitude. Indeed, the higher the altitude, the larger the monitored area and the higher the energy consumption. When an UAV runs out of battery, it is replaced by a new one. The aim is to locate UAVs in order to cover the piece of plane in which the target moves by using a minimum number of UAVs. Each target has to be monitored for each instant time. The problem under consideration is mathematically represented by defining mixed integer non-linear optimization models. Heuristic procedures are defined and they are based on restricted mixed integer programming (MIP) formulation of the problem. A computational study is carried out to assess the behaviour of the proposed models and MIP-based heuristics. A comparison in terms of efficiency and effectiveness among models and heuristics is carried out.

关键词： Targets tracking Unmanned aerial vehicles non-linear programming Matheuristic

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Modelling the economic trade-offs of irrigation pipeline investments for improved energy management

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WATER SA 2016年第4期42卷 542-550页

作者： Venter, Marcill Grove, Bennie Univ Free State Dept Agr Econ POB 339 ZA-9300 Bloemfontein South Africa

Higher electricity tariffs have accentuated the importance of the trade-off between lowering investment cost by buying pipes with smaller diameters and the higher operating costs that result from the increased power requirement to overcome the higher friction losses of the thinner pipes. The Soil Water Irrigation Planning and Energy Management (SWIP-E) mathematical programming model was developed and applied in this paper to provide decision support regarding the optimal mainline pipe diameter, irrigation system delivery capacity and size of the irrigation system. SWIP-E unifies the interrelated linkages between mainline pipe diameter choice and the timing of irrigation events in conjunction with time-of-use electricity tariffs. The results showed that the large centre pivot resulted in higher net present values than the smaller centre pivot and the lower delivery capacities were more profitable than higher delivery capacities. More intense management is, however, necessary for delivery capacities lower than 12 mm.d(-1) to minimise irrigation during peak timeslots. Variable electricity costs are highly dependent on the interaction between kilowatt requirement and irrigation hours. For the large centre pivot the interaction is dominated by changes in kilowatt whereas the effect of irrigation hours in relation to kilowatts is more important for smaller pivots. Optimised friction loss expressed as a percentage of the length of the pipeline was below 0.6%, which is much lower than the design norm of 1.5% that is endorsed by the South African Irrigation Institute. The main conclusion is that care should be taken when applying the friction loss norm when sizing irrigation mainlines because the norm will result in pipe diameters that are too small, consequently resulting in increased lifecycle operating costs. A clear need for the revision of the friction loss design norm was identified by this research.

关键词： non-linear programming economic trade-off electricity costs irrigation system investment costs water management net present value

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Real-time smart distribution system reconfiguration using complementarity

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ELECTRIC POWER SYSTEMS RESEARCH 2016年 134卷 97-104页

作者： Masteri, K. Venkatesh, B. Ryerson Univ Toronto ON Canada Ryerson Univ Dept Elect & Comp Engn Toronto ON Canada Ryerson Univ Ctr Urban Energy Toronto ON Canada

Smart Radial Distribution Systems (SRDS) of the future will have improved reliability, performance and flexibility in operation by using algorithms such as optimal reconfiguration in real-time in their distribution management systems. However, today, optimal reconfiguration algorithms are largely academic because of challenges such as they (1) depend upon heuristic techniques that require repeated runs and are not suitable for real-time applications, (2) do not guarantee an optimal solution and, (3) do not provide insight into solution space. In order to realize SRDS of the future, a real-time optimal reconfiguration algorithm is proposed, which uses a classic nonlinear optimization technique and guarantees an optimal solution in the least time. The method is based upon a complementarity technique that transforms discontinuous solution spaces into continuous, enabling use of classical nonlinear optimization techniques without resorting to heuristics. Using the complementarity technique, a nonlinear optimization formulation and classical solution method is needed to optimally reconfigure a SRDS and to minimize losses while obtaining an acceptable voltage solution is proposed. This is successfully demonstrated on 7-bus, 33-bus, and 69-bus distribution systems and the results are compared with those available in literature with respect to solution time, accuracy in results and robustness of the proposed algorithm and demonstrate superiority of the proposed technique. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Radial distribution system Real-time reconfiguration Complementarity non-linear programming

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A priority based assignment problem

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APPLIED MATHEMATICAL MODELLING 2016年第17-18期40卷 7784-7795页

作者： Kaur, Prabhjot Sharma, Anuj Verma, Vanita Dahiya, Kalpana Panjab Univ Univ Inst Engn & Technol Chandigarh 160014 India Panjab Univ Dept Math Chandigarh 160014 India Panjab Univ Dept Comp Sci & Applicat Chandigarh 160014 India

This paper discusses a priority based assignment problem related to an industrial project consisting of a total of n jobs. Depending upon its work breakdown structure, the execution of the project is carried out in two stages where the m primary jobs are performed first, in Stage-I whereas the (n - m) secondary jobs are performed later in Stage-II (as the secondary jobs cannot be performed until the primary jobs are finished). A number of manufacturing units exactly equal to n, each of them capable of performing all the n jobs involved in the project, are available. A tentative job-performance time taken by each of these manufacturing units for each of the n jobs is available. The purpose of the current study is to assign the jobs to the manufacturing units in such a way that the two stage execution of the project can be carried out in the minimum possible time. For this, a polynomial time iterative algorithm is proposed, which at each iteration, aims at selecting m manufacturing units to perform primary jobs corresponding to which, the remaining (n - m) manufacturing units perform the secondary jobs optimally and from this selection, a pair of times of Stage-I and Stage-II is obtained. The proposed algorithm is such that at each iteration, time of Stage-I decreases strictly and time of Stage-II increases. Out of the pairs so generated, the one with minimum sum of Stage-I and Stage-II times is considered as optimum and the corresponding assignment as the optimal assignment. A numerical illustration is given in the support of the theory. Also, the proposed algorithm is implemented and tested on a variety of test problems and the average run time for each problem is calculated. (C) 2016 Elsevier Inc. All rights reserved.

关键词： Optimization non-linear programming Combinatorial analysis Allocation Assignment problem

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Solving fractional optimal control problems with fixed or free final states by Haar wavelet collocation method

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IMA JOURNAL OF MATHEMATICAL CONTROL AND INFORMATION 2016年第2期33卷 543-561页

作者： Hosseinpour, Soleiman Nazemi, Alireza Univ Shahrood Sch Math Sci Dept Math POB ***-316 Shahrood Iran

A numerical method using Haar wavelets for solving fractional optimal control problems (FOCPs) is studied. The fractional derivative in these problems is in the Caputo sense. The operational matrix of fractional Riemann-Liouville integration and the direct collocation method are considered. The proposed technique is applied to transform the state and control variables into non-linear programming (NLP) parameters at collocation points. An NLP solver can then be used to solve FOCPs. Illustrative examples are included to demonstrate the validity and applicability of the proposed method.

关键词： fractional optimal control problems Caputo derivative rationalized Haar functions operational matrix non-linear programming

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Base Station Location -Aware Optimization Model of the Lifetime of Wireless Sensor Networks

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MOBILE NETWORKS & APPLICATIONS 2016年第1期21卷 10-17页

作者： Nguyen Thanh Tung Huynh Thi Thanh Binh Vietnam Natl Univ Int Sch Hanoi Vietnam Hanoi Univ Sci & Technol Hanoi Vietnam

Recently, wireless sensor networks (WSNs) have been progressively applied in various fields and areas. However, its limited energy resources is indisputably one of the weakest point that strongly affects the network's lifetime. A WSN consists of a sensor node set and a base station. The initial energy of each sensor node will be depleted continuously during data transmission to the base station either directly or through intermediate nodes, depending on the distance between sending and receiving nodes. This paper consider determining an optimal base station location such that the energy consumption is kept lowest, maximizing the network's lifetime and propose a nonlinear programming model for this optimizing problem. Our proposed method for solving this problem is to combine methods mentioned in [1] respectively named the centroid, the smallest total distances, the smallest total squared distances and two greedy methods. Then an improved greedy method using a LP tool provided in Gusek library is presented. Finally, all of the above methods are compared with the optimized solution over 30 randomly created data sets. The experimental results show that a relevant location for the base station is essential.

关键词： Base station location Wireless sensor network Routing non-linear programming

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Changing old habits: The case of feeding patterns in anaerobic digesters

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RENEWABLE ENERGY 2016年 92卷 212-221页

作者： Willeghems, Gwen Buysse, Jeroen Univ Ghent Fac Biosci Engn Dept Agr Econ B-9000 Ghent Belgium

A non-linear programming model was developed to maximize the economic profit from an anaerobic co-digester. The model consists of a combination of technical and economic equations, linked through the biogas production variable. Five scenarios were simulated. These differed with regard to substrate inlet mass flow rate, organic loading rate and hydraulic retention time. The impact on biogas production was investigated and an economic analysis was undertaken based on the concepts of profitability and Net Present Value. The model results indicate that varying the substrate inlet mass flow rate and organic loading rate could have a positive impact on the profitability of co-digesters in Flanders. This can be achieved either by increasing the interval time between feedstock input, or by feeding individual streams of feedstock separately into the system, while at the same time reducing the hydraulic retention. time. (C) 2016 The Authors. Published by Elsevier Ltd.

关键词： non-linear programming Kinetic model Biogas plant Economic profit Organic loading rate

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Stand-Level Forest Management Planning ApproachesEEXONLY

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CURRENT FORESTRY REPORTS 2016年第3期2卷 163-176页

作者： Yoshimoto, Atsushi Asante, Patrick Konoshima, Masashi Inst Stat Math Dept Math Anal & Stat Inference 10-3 Midori Cho Tachikawa Tokyo 1908562 Japan Govt British Columbia Minist Forests Lands & Nat Resources Operat POB 9515 Victoria BC V8W 9C2 Canada Univ Ryukyus Fac Agr 1 Senbaru Okinawa 9030213 Japan

Seeking an optimal operational regime under different management environments has been one of the main concerns of forest managers. Traditionally, the main operational regime includes planting density or regeneration scheme, thinning time/intensity, and optimal time to harvest over the given time horizon. Deterministic approaches to tackle this type of optimization problem with different controls have dominated the solution techniques in forestry literature. We present in this paper an overview of the methodologies used in stand-level optimization, in which we show the strengths and weaknesses of these methodologies as well as provide comments on the effectiveness of the methodology. We then propose a new dynamic programing approach for generalizing solution specification and techniques.

关键词： non-linear programming Heuristics Dynamic programming Dynamic optimization Forest stand-level planning

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Environmental evaluation of biomass pelleting using life cycle assessment

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BIOMASS & BIOENERGY 2016年 84卷 107-117页

作者： Kylili, Angeliki Christoforou, Elias Fokaides, Paris A. Frederick Univ Sch Engn & Appl Sci CY-1036 Nicosia Cyprus

The exploitation of biomass for energy production purposes can significantly reduce the environmental burdens associated with the highly criticized fossil fuelled energy production. Life cycle assessment (LCA) methodology has proven to be one of the most effective tools for carrying out environmental impact analysis of any process or system. The interpretation of the findings of LCA can be used as a basis for recommendations and decision making in accordance to the goal and scope definition. The aim of this paper is to conduct a comprehensive LCA for the environmental evaluation of the biomass pelleting process with the focus being on the transportation and manufacturing stages. To achieve this aim, four scenarios are presented, investigating the pelleting process of olive husk, an abundant waste biomass found in Cyprus. Two alternative scenarios are developed in an effort to compare the centralised and the decentralised management of olive husk. Regarding those two scenarios, a novel mathematical parametric model was developed and non-linear programming was applied for the computation of the optimal locations for a set of management facilities which achieve the lowest energy needs for transportation purposes. Additionally, a third and fourth scenario aimed to the comparison of the potential improvement of the environmental footprint of the olive husk pellets with regard to their reference cases (Scenario 1 and 2 respectively), when Renewable Energy Sources (RES) are incorporated in the pelleting process system. The authors concluded that the selection of location for the biomass management centres, as well as the employment of renewable energy technologies (RET) for energy generation can significantly affect the environmental impact of biomass utilisation. The environmental impact of olive husk pellet production was improved by more than 85% in selected impact categories when RES were incorporated in the manufacturing stage. The comparison of centralised and decent

关键词： Life cycle assessment Pellets non-linear programming Olive husk

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Cutting and packing problems for irregular objects with continuous rotations: mathematical modelling and non-linear optimization

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JOURNAL OF THE OPERATIONAL RESEARCH SOCIETY 2016年第5期67卷 786-800页

作者： Stoyan, Yuriy Pankratov, Alexander Romanova, Tatiana Natl Acad Sci Ukraine Inst Mech Engn Problems UA-61046 Kharkov Ukraine

We further improve our methodology for solving irregular packing and cutting problems. We deal with an accurate representation of objects bounded by circular arcs and line segments and allow their continuous rotations and translations within rectangular and circular containers. We formulate a basic irregular placement problem which covers a wide spectrum of packing and cutting problems. We provide an exact non-linear programming (NLP) model of the problem, employing ready-to-use phi-functions. We develop an efficient solution algorithm to search for local optimal solutions for the problem in a reasonable time. The algorithm reduces our problem to a sequence of NLP subproblems and employs optimization procedures to generate starting feasible points and feasible subregions. Our algorithm allows us to considerably reduce the number of inequalities in NLP subproblems. To show the benefits of our methodology we give computational results for a number of new challenger and the best known benchmark instances.

关键词： cutting and packing irregular shapes circular arcs continuous rotations non-linear programming optimization

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