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An extended corner point method for the synthesis of flexible water network

PROCESS SAFETY AND ENVIRONMENTAL PROTECTION 2021年 148卷 210-224页

作者： Poplewski, Grzegorz Foo, Dominic C. Y. Rzeszow Univ Technol Dept Chem & Proc Engn Al Powstancow Warszawy 6 PL-35959 Rzeszow Poland Univ Nottingham Malaysia Dept Chem & Environm Engn Ctr Green Technol Broga Rd Semenyih 43500 Selangor Malaysia

This paper presents an extended methodology for the design of flexible water network (FWN). In many water network systems, parameters of the water-using processes (e.g. flow rate, concentration, etc.) vary due to operational changes. Hence, it is important to synthesize a FWN that can absorb these changes, so to ensure business sustainability. In this paper, the recently established corner point method for FWN synthesis is extended to cater the discrete way of process parameters change. The newly proposed methodology ensures the synthesized FWN to achieve the intended objective, i.e. minimum fresh water intake and minimum total pipeline length, while satisfying the various process constraints (e.g. flow rate, concentration, etc.). To address the multiple-objective problem, a three-step optimization method has been developed. The corner point method is also extended to synthesize a FWN that achieves the minimum total annualized costs (TAC). A literature case study was used to show the usefulness of the proposed method. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

关键词： Process integration Water minimization mathematical programming Process changes Flexible designa

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A heuristic algorithm for optimal cost design of gravity-fed water distribution networks. a real case study

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APPLIED mathematical MODELLING 2021年 95卷 379-395页

作者： Aragones, David G. Calvo, Gabriel F. Galan, Alvaro Univ Castilla La Mancha Sch Civil Engn Dept Math Ciudad Real Spain Univ Castilla La Mancha Sch Civil Engn Dept Construct & Civil Engn Ciudad Real Spain

In this work, we put forward a new algorithm for minimizing the total cost of gravity-fed water distribution networks (WDN) by optimally choosing pipe diameters. Our approach is based on network theory and heuristic procedures and aims at overcoming a number of limitations found in the current scientific literature. WDN optimization problems belong to those that are discrete, non-linear and non-convex, making the use of standard optimization algorithms inefficient. Furthermore, resorting to metaheuristic search techniques to test many different solutions has an exceedingly expensive computational cost, due to the inherent complexity of the problem. Here we present an efficient heuristic algorithm that circumvents these limitations, exploiting detailed aspects, such as the specific network topology. In order to check the capability of the algorithm in a realistic setting, we have developed and analyzed a mathematical model of a water distribution network in a Spanish municipality, considerably larger than those addressed in previous works. Our numerical results indicate significant potential construction savings over current design practices, which justifies the interest of our approach in addressing this class of optimization problems. (c) 2021 Elsevier Inc. All rights reserved.

关键词： Water supply Civil engineering Hydraulics Graph theory Combinatorial optimization mathematical programming

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Optimization problems for machine learning: A survey

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EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 2021年第3期290卷 807-828页

作者： Gambella, Claudio Ghaddar, Bissan Naoum-Sawaya, Joe IBM Res Ireland Dublin 15 Ireland Univ Western Ontario Ivey Business Sch London ON N6G 0N1 Canada

This paper surveys the machine learning literature and presents in an optimization framework several commonly used machine learning approaches. Particularly, mathematical optimization models are presented for regression, classification, clustering, deep learning, and adversarial learning, as well as new emerging applications in machine teaching, empirical model learning, and Bayesian network structure learning. Such models can benefit from the advancement of numerical optimization techniques which have already played a distinctive role in several machine learning settings. The strengths and the shortcomings of these models are discussed and potential research directions and open problems are highlighted. (C) 2020 Elsevier B.V. Allrights reserved.

关键词： Analytics mathematical programming Machine learning Deep learning

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On the Use of Equivalence Classes for Optimal and Suboptimal Bin Packing and Bin Covering

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IEEE TRANSACTIONS ON AUTOMATION SCIENCE AND ENGINEERING 2021年第1期18卷 369-381页

作者： Roselli, Sabino Hagebring, Fredrik Riazi, Sarmad Fabian, Martin Akesson, Knut Chalmers Univ Technol Dept Elect Engn SE-41296 Gothenburg Sweden

Bin packing and bin covering are important optimization problems in many industrial fields, such as packaging, recycling, and food processing. The problem concerns a set of items, each with its own value, that are to be sorted into bins in such a way that the total value of each bin, as measured by the sum of its item values, is not above (for packing) or below (for covering) a given target value. The optimization problem concerns minimizing, for bin packing, or maximizing, for bin covering, the number of bins. This is a combinatorial NP-hard problem, for which true optimal solutions can only be calculated in specific cases, such as when restricted to a small number of items. To get around this problem, many suboptimal approaches exist. This article describes the formulations of the bin packing and covering problems that allow finding the true optimum, for instance, counting hundreds of items using general-purpose MILP-solvers. Also presented are suboptimal solutions that come within less than 10% of the optimum while taking significantly less time to calculate, even ten to 100 times faster, depending on the required accuracy. Note to Practitioners-A typical case for bin covering is in food processing where food items are automatically sorted into trays of similar weight so that the overweight is minimized. Another application is in recycling, where items such as batteries should be put in crates of similar weight, so that the crates do not exceed a target weight due to later manual handling, but, at the same time, we want as few crates as possible. This is a bin packing problem. On an industrial scale, these tasks are fully automated. Though modern software tool's efficiency to solve bin sorting problems has increased significantly in later years, the problems are inherently tough in the sense that the solution time grows exponentially with the number of items. This limits the problem sizes that can be solved to optimality within a reasonable time. Therefore, much

关键词： Combinatorial mathematics integer linear programming mathematical programming optimization sorting

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Regret Theory-Based Case-Retrieval Method with Multiple Heterogeneous Attributes and Incomplete Weight Information

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INTERNATIONAL JOURNAL OF COMPUTATIONAL INTELLIGENCE SYSTEMS 2021年第1期14卷 1022-1033页

作者： Zhang, Kai Wang, Ying-Ming Zheng, Jing Fujian Chuanzheng Commun Coll Coll Informat & Intelligent Transportat Fuzhou 350007 Fujian Peoples R China Wuchang Univ Technol Business Sch Wuhan 430223 Hubei Peoples R China Fujian Jiangxia Univ Coll Elect & Informat Sci Fuzhou 350108 Fujian Peoples R China

Case retrieval is a crucial step in case-based reasoning (CBR), which is related to decision-making effectiveness. To improve decision support, CBR usually calculates case similarity and evaluates utility. However, the psychological behavior of decision makers is seldom considered in case retrieval. This paper proposes a novel case-retrieval method that deals with multiple heterogeneous attributes and incomplete weight information based on regret theory (RT). First, we define the function of the perceived utility based on attribute similarity and RT. Next, a mathematical programming model is constructed to determine the attribute weights based on linear programming technique for multidimensional analysis of preference (LINMAP). Based on this, we can calculate the perceived utility and determine a set of similar historical cases. Furthermore, the utilities of the evaluated attributes are calculated based on RT and LINMAP. Subsequently, we compute the comprehensive utilities of similar historical cases and obtain the ranking order of similar historical cases. Thus, the most suitable historical case is obtained. Finally, a case study of a gas explosion is conducted to illustrate the use of the proposed method. (C) 2021 The Authors. Published by Atlantis Press B.V.

关键词： Case retrieval Regret theory Multiple heterogeneous attributes Incomplete weight information mathematical programming

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Hysteretic models with stiffness and strength degradation in a mathematical programming format

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INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS 2013年 51卷 10-27页

作者： Sivaselvan, M. V. SUNY Buffalo Dept Civil Struct & Environm Engn Buffalo NY 14260 USA

In this paper, we present several hysteretic models formulated using an energy approach. In each case, the behavior of the model is completely described by specifying two scalar-valued functions-a stored energy function and a dissipation potential. Consequently, different types of mathematical programs arise in incremental non-linear analyses involving these models. It is relatively well-known how classical plasticity models can be described using an energy approach, and lead to mathematical programming problems. However, in this paper, we demonstrate that plasticity models with nonassociated flow rules, softening plasticity or strength degradation models, and damage or stiffness degradation models can be represented in this framework as well. The energy approach serves to unify formulation and implementation of a broad class of hysteretic models. In addition, it helps motivate regularization strategies needed in optimization and inverse problems. The types of models considered in this paper are ones commonly applied in earthquake engineering. MATLAB implementations are included as online supplemental data with this paper to illustrate the conceptual simplicity of implementing models formulated using this approach. (C) 2012 Elsevier Ltd. All rights reserved.

关键词： Hysteretic models Degradation mathematical programming Optimization Complementarity Standard material

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A dual reformulation and solution framework for regularized convex clustering problems

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EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 2021年第3期290卷 844-856页

作者： Pi, J. Wang, Honggang Pardalos, Panos M. Siemens Corp Corp Technol Princeton NJ 08540 USA Calif Polytech State Univ Pomona Dept Technol & Operat Management Pomona CA 91768 USA Univ Florida Dept Ind & Syst Engn Gainesville FL 32611 USA

Clustering techniques are powerful tools commonly used in statistical learning and data analytics. Most of the past research formulates clustering tasks as a non-convex problem, where a global optimum often cannot be found. Recent studies show that hierarchical clustering and k-means clustering can be relaxed and analyzed as a convex problem. Moreover, sparse convex clustering algorithms are proposed to extend the convex clustering framework to high-dimensional space by introducing an adaptive group-Lasso penalty term. Due to the non-smoothness nature of the associated objective functions, there are still no efficient fast-convergent algorithms for clustering problems even with convexity. In this paper, we first review the structure of convex clustering problems and prove the differentiability of their dual problems. We then show that such reformulated dual problems can be efficiently solved by the accelerated first-order methods with the feasibility projection. Furthermore, we present a general framework for convex clustering with regularization terms and discuss a specific implementation of this framework using L-1,L-1-norm. We also derive the dual form for the regularized convex clustering problems and show that it can be efficiently solved by embedding a projection operator and a proximal operator in the accelerated gradient method. Finally, we compare our approach with several other co-clustering algorithms using a number of example clustering problems. Numerical results show that our models and solution methods outperform all the compared algorithms for both convex clustering and convex co-clustering. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Global optimization Convex clustering mathematical programming Gradient descent Duality

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A variational rigid-block modeling approach to nonlinear elastic and kinematic analysis of failure mechanisms in historic masonry structures subjected to lateral loads

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EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS 2021年第12期50卷 3332-3354页

作者： Portioli, Francesco P. A. Godio, Michele Calderini, Chiara Lourenco, Paulo B. Univ Naples Federico II Dept Struct Engn & Architecture Via Forno Vecchio 36 I-80134 Naples Italy RISE Res Inst Sweden Boras Sweden Univ Genoa Dept Civil Chem & Environm Engn Genoa Italy Univ Minho Dept Civil Engn ISISE Guimaraes Portugal

Displacement-based methods contained in recent standards for seismic safety assessment require the determination of the full nonlinear pushover curve for local failure mechanisms in historic masonry structures. This curve should reflect both the initial elastic behavior and the rigid body behavior after the activation of rocking. In this work, a rigid block model is proposed for the displacement-based seismic assessment of local collapse mechanisms of these structures. Masonry is modeled as an assemblage of two-dimensional rigid blocks in contact through frictional interfaces. Two types of contact models are formulated to capture, respectively, the pre and postpeak branches of the pushover curve: a unilateral elastic contact model, capturing the initial nonlinear behavior up to the force capacity of the structure, corresponding to the activation of the collapse mechanism, and a rigid contact model with finite friction and compressive strength, which describes the rigid-body rocking behavior up to the attainment of the displacement capacity of the structure. Tension-only elements are also implemented to model strengthening interventions with tie-rods. The contact problems associated with the elastic and rigid contact models are formulated using mathematical programming. For both models, a sequential solution procedure is implemented to capture the variation of the load multiplier with the increasing deformation of the structure (P-Delta effect). The accuracy of the modeling approach in reproducing the pushover curve of masonry panels subjected to horizontal seismic loads is evaluated on selected case studies. The solution is first tested against hand calculations, existing analytical models, and distinct element simulations. Then, comparisons against experimental tests follow. As a final application, the failure mechanism and pushover curve of a triumphal masonry arch are predicted by the model and its seismic assessment is performed according to codified force- and

关键词： displacement-based method distinct element method large displacements masonry mathematical programming rigid block model sequential limit analysis unilateral elastic contacts

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A scenario-based decision support system for allocating temporary-disaster-response facilities

JOURNAL OF THE FACULTY OF ENGINEERING AND ARCHITECTURE OF GA...

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JOURNAL OF THE FACULTY OF ENGINEERING AND ARCHITECTURE OF GAZI UNIVERSITY 2021年第3期36卷 1500-1514页

作者： Cavdur, Fatih Sebatli-Saglam, Asli Kose-Kucuk, Merve Bursa Uludag Univ Muhendisl Fak Endustri Muhendisligi Bolumu TR-16059 Bursa Turkey

Disaster operations management is carried out in a chaotic environment under uncertainty and time pressure. Therefore, it is necessary to use information and communication technologies in the decision making processes. In this study, a standalone decision support system is developed for temporary-disaster-response facilities allocation for relief supplies distribution as one of the important problems in disaster operations management. The decision support system consists of three main components as its database, decision engine and user interface. It is noted that the decision support system allows decision makers to allocate temporary-disaster-response facilities under many different disaster situations by utilizing a scenario-based approach. Thus, disaster operations managers are given the opportunity to create different scenarios and analyze the results that will help them make critical decisions before and during the disaster. In the scenario definition process, in addition to taking into account different values of affected population rate and planning period, some model configurations consisting of the combinations of various problem parameters are also defined. Although it is illustrated with a specific example case in this paper, the flexibility of the system allows its users to consider other cases with different scenarios. Due to the user-friendly interface of the decision support system, reports of the results obtained for various disaster scenarios are presented to the user in an understandable way. The proposed system might be a useful tool to help decision makers in allocating temporary-disaster-response facilities for relief supplies distribution.

关键词： Humanitarian logistics facility allocation relief supplies distribution decision support systems mathematical programming

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Economic potential of adopting genomic technology in Alberta's tree improvement sector

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FORESTRY CHRONICLE 2021年第3期97卷 277-299页

作者： Wang, Shuo An, Henry Chang, Wei-Yew Gaston, Chris Thomas, Barb R. Univ Maryland Dept Agr & Resource Econ Symons Hall College Pk MD 20742 USA Univ Alberta Dept Resource Econ & Environm Sociol 551 Gen Serv Bldg Edmonton AB T6G 2H1 Canada Lanzhou Univ Sch Econ 222 South Tianshui Rd Lanzhou 730000 Gansu Peoples R China Univ British Columbia Dept Wood Sci 4028 Forest Sci Ctr Vancouver BC V6T 1Z4 Canada Univ Alberta Dept Renewable Resources 442 Earth Sci Bldg Edmonton AB T6G 2E3 Canada

The adoption of genomic technology and the use of improved seeds are expected to improve timber productivity in Alberta. However, this improvement will need to take place within the confines of the public-private nature of the sector where 93% of the total forest area is publicly owned. The purpose of this study is to explore the extent to which a timber harvest policy known as the allowable cut effect can affect the welfare outcomes of adopting genomics-assisted tree breeding. Using the forest industry of Alberta as the empirical setting, the economic returns to the adoption of this new breed-ing technology in lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) and white spruce (Picea glauca (Moench) Voss) are calculated by estimating a timber supply model and a spatial equilibrium model. Under certain pol-icy and technology improvement scenarios, the economic returns are negative, which would result in non-adoption of the technology. However, under other feasible conditions, the payoffs of genomics-assisted tree breeding research are large and positive. These results illustrate the important role that government policies can have on the returns to adopting new technologies.

关键词： allowable cut effect forestry genomics mathematical programming returns to R&D tree improvement

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