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  Subjects -> ENGINEERING (Total: 2156 journals)
    - CHEMICAL ENGINEERING (186 journals)
    - CIVIL ENGINEERING (168 journals)
    - ELECTRICAL ENGINEERING (93 journals)
    - ENGINEERING (1164 journals)
    - ENGINEERING MECHANICS AND MATERIALS (355 journals)
    - HYDRAULIC ENGINEERING (55 journals)
    - INDUSTRIAL ENGINEERING (54 journals)
    - MECHANICAL ENGINEERING (81 journals)

ENGINEERING (1164 journals)            First | 2 3 4 5 6 7 8 9 | Last

International Journal of Hypersonics     Full-text available via subscription   (Followers: 3)
International Journal of Imaging Systems and Technology     Hybrid Journal   (Followers: 2)
International Journal of Impact Engineering     Hybrid Journal   (Followers: 8)
International Journal of Information Acquisition     Hybrid Journal   (Followers: 1)
International Journal of Innovation and Applied Studies     Open Access   (Followers: 3)
International Journal of Innovation Science     Full-text available via subscription   (Followers: 6)
International Journal of Innovative Technology and Research     Open Access  
International Journal of Integrated Engineering     Open Access   (Followers: 1)
International Journal of Intelligent Engineering Informatics     Hybrid Journal  
International Journal of Intelligent Systems and Applications in Engineering     Open Access  
International Journal of Lifecycle Performance Engineering     Hybrid Journal   (Followers: 1)
International Journal of Machine Tools and Manufacture     Hybrid Journal   (Followers: 5)
International Journal of Manufacturing Research     Hybrid Journal   (Followers: 5)
International Journal of Manufacturing Technology and Management     Hybrid Journal   (Followers: 7)
International Journal of Materials and Product Technology     Hybrid Journal   (Followers: 4)
International Journal of Mathematical Education in Science and Technology     Hybrid Journal   (Followers: 8)
International Journal of Mathematics in Operational Research     Hybrid Journal   (Followers: 1)
International Journal of Medical Engineering and Informatics     Hybrid Journal   (Followers: 5)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 4)
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 1)
International Journal of Microwave Science and Technology     Open Access   (Followers: 2)
International Journal of Mobile Network Design and Innovation     Hybrid Journal   (Followers: 3)
International Journal of Multiphase Flow     Hybrid Journal   (Followers: 2)
International Journal of Nanomanufacturing     Hybrid Journal   (Followers: 1)
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Nanotechnology     Hybrid Journal   (Followers: 5)
International Journal of Nanotechnology and Molecular Computation     Full-text available via subscription   (Followers: 3)
International Journal of Navigation and Observation     Open Access   (Followers: 11)
International Journal of Network Management     Hybrid Journal  
International Journal of Nonlinear Sciences and Numerical Simulation     Hybrid Journal  
International Journal of Numerical Methods for Heat & Fluid Flow     Hybrid Journal   (Followers: 7)
International Journal of Optics     Open Access   (Followers: 1)
International Journal of Organisational Design and Engineering     Hybrid Journal   (Followers: 10)
International Journal of Pattern Recognition and Artificial Intelligence     Hybrid Journal   (Followers: 6)
International Journal of Pavement Engineering     Hybrid Journal   (Followers: 3)
International Journal of Physical Modelling in Geotechnics     Hybrid Journal   (Followers: 3)
International Journal of Plasticity     Hybrid Journal   (Followers: 6)
International Journal of Plastics Technology     Hybrid Journal   (Followers: 1)
International Journal of Polymer Analysis and Characterization     Hybrid Journal   (Followers: 5)
International Journal of Polymer Science     Open Access   (Followers: 20)
International Journal of Precision Engineering and Manufacturing     Hybrid Journal   (Followers: 5)
International Journal of Precision Engineering and Manufacturing-Green Technology     Hybrid Journal  
International Journal of Precision Technology     Hybrid Journal  
International Journal of Pressure Vessels and Piping     Hybrid Journal   (Followers: 3)
International Journal of Production Economics     Hybrid Journal   (Followers: 13)
International Journal of Quality and Innovation     Hybrid Journal   (Followers: 4)
International Journal of Quality Assurance in Engineering and Technology Education     Full-text available via subscription   (Followers: 2)
International Journal of Quality Engineering and Technology     Hybrid Journal   (Followers: 2)
International Journal of Quantum Information     Hybrid Journal  
International Journal of Rapid Manufacturing     Hybrid Journal   (Followers: 3)
International Journal of Reliability, Quality and Safety Engineering     Hybrid Journal   (Followers: 7)
International Journal of Renewable Energy Technology     Hybrid Journal   (Followers: 9)
International Journal of Robust and Nonlinear Control     Hybrid Journal   (Followers: 3)
International Journal of Science Engineering and Advance Technology     Open Access  
International Journal of Sediment Research     Full-text available via subscription   (Followers: 1)
International Journal of Self-Propagating High-Temperature Synthesis     Hybrid Journal   (Followers: 2)
International Journal of Signal and Imaging Systems Engineering     Hybrid Journal  
International Journal of Six Sigma and Competitive Advantage     Hybrid Journal  
International Journal of Social Robotics     Hybrid Journal   (Followers: 2)
International Journal of Software Engineering and Knowledge Engineering     Hybrid Journal   (Followers: 2)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 2)
International Journal of Speech Technology     Hybrid Journal   (Followers: 4)
International Journal of Spray and Combustion Dynamics     Full-text available via subscription   (Followers: 6)
International Journal of Superconductivity     Open Access  
International Journal of Surface Engineering and Interdisciplinary Materials Science     Full-text available via subscription   (Followers: 1)
International Journal of Surface Science and Engineering     Hybrid Journal   (Followers: 8)
International Journal of Sustainable Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Manufacturing     Hybrid Journal   (Followers: 4)
International Journal of Systems and Service-Oriented Engineering     Full-text available via subscription  
International Journal of Systems Assurance Engineering and Management     Hybrid Journal  
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 2)
International Journal of Technoethics     Full-text available via subscription   (Followers: 1)
International Journal of Technology Management and Sustainable Development     Hybrid Journal   (Followers: 1)
International Journal of Technology Policy and Law     Hybrid Journal   (Followers: 5)
International Journal of Telemedicine and Applications     Open Access   (Followers: 2)
International Journal of Thermal Sciences     Hybrid Journal   (Followers: 7)
International Journal of Thermodynamics     Open Access   (Followers: 2)
International Journal of Turbo & Jet-Engines     Hybrid Journal  
International Journal of Ultra Wideband Communications and Systems     Hybrid Journal  
International Journal of Vehicle Autonomous Systems     Hybrid Journal   (Followers: 1)
International Journal of Vehicle Design     Hybrid Journal   (Followers: 8)
International Journal of Vehicle Information and Communication Systems     Hybrid Journal   (Followers: 2)
International Journal of Vehicle Noise and Vibration     Hybrid Journal   (Followers: 3)
International Journal of Vehicle Safety     Hybrid Journal   (Followers: 5)
International Journal of Vehicular Technology     Open Access   (Followers: 3)
International Journal of Virtual Technology and Multimedia     Hybrid Journal   (Followers: 4)
International Journal of Wavelets, Multiresolution and Information Processing     Hybrid Journal  
International Journal on Artificial Intelligence Tools     Hybrid Journal   (Followers: 4)
International Nano Letters     Open Access   (Followers: 9)
International Review of Applied Sciences and Engineering     Full-text available via subscription  
International Scholarly Research Notices     Open Access   (Followers: 226)
Inverse Problems in Science and Engineering     Hybrid Journal   (Followers: 2)
Ionics     Hybrid Journal  
IPTEK The Journal for Technology and Science     Open Access  
IRBM News     Full-text available via subscription  
Ironmaking & Steelmaking     Hybrid Journal   (Followers: 2)
Irrigation and Drainage Systems     Hybrid Journal   (Followers: 1)
ISA Transactions     Full-text available via subscription   (Followers: 1)
IT Professional     Full-text available via subscription   (Followers: 3)
Johnson Matthey Technology Review     Open Access   (Followers: 2)

  First | 2 3 4 5 6 7 8 9 | Last

Journal Cover   Journal of Global Optimization
  [SJR: 0.919]   [H-I: 51]   [4 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1573-2916 - ISSN (Online) 0925-5001
   Published by Springer-Verlag Homepage  [2299 journals]
  • On the existence of saddle points for nonlinear second-order cone
           programming problems
    • Abstract: Abstract In this paper, we study the existence of local and global saddle points for nonlinear second-order cone programming problems. The existence of local saddle points is developed by using the second-order sufficient conditions, in which a sigma-term is added to reflect the curvature of second-order cone. Furthermore, by dealing with the perturbation of the primal problem, we establish the existence of global saddle points, which can be applicable for the case of multiple optimal solutions. The close relationship between global saddle points and exact penalty representations are discussed as well.
      PubDate: 2015-07-01
       
  • Unified framework for the propagation of continuous-time enclosures for
           parametric nonlinear ODEs
    • Abstract: Abstract This paper presents a framework for constructing and analyzing enclosures of the reachable set of nonlinear ordinary differential equations using continuous-time set-propagation methods. The focus is on convex enclosures that can be characterized in terms of their support functions. A generalized differential inequality is introduced, whose solutions describe such support functions for a convex enclosure of the reachable set under mild conditions. It is shown that existing continuous-time bounding methods that are based on standard differential inequalities or ellipsoidal set propagation techniques can be recovered as special cases of this generalized differential inequality. A way of extending this approach for the construction of nonconvex enclosures is also described, which relies on Taylor models with convex remainder bounds. This unifying framework provides a means for analyzing the convergence properties of continuous-time enclosure methods. The enclosure techniques and convergence results are illustrated with numerical case studies throughout the paper, including a six-state dynamic model of anaerobic digestion.
      PubDate: 2015-07-01
       
  • Extended Lorentz cones and mixed complementarity problems
    • Abstract: Abstract In this paper we extend the notion of a Lorentz cone in a Euclidean space as follows: we divide the index set corresponding to the coordinates of points in two disjoint classes. By definition a point belongs to an extended Lorentz cone associated with this division, if the coordinates corresponding to one class are at least as large as the norm of the vector formed by the coordinates corresponding to the other class. We call a closed convex set isotone projection set with respect to a pointed closed convex cone if the projection onto the set is isotone (i.e., order preserving) with respect to the partial order defined by the cone. We determine the isotone projection sets with respect to an extended Lorentz cone. In particular, a Cartesian product between an Euclidean space and any closed convex set in another Euclidean space is such a set. We use this property to find solutions of general mixed complementarity problems recursively.
      PubDate: 2015-07-01
       
  • Projective dualities for quasiconvex problems
    • Abstract: Abstract We study two dualities that can be applied to quasiconvex problems. They are conjugacies deduced from polarities. They are characterized by the polar sets of sublevel sets. We give some calculus rules for the associated subdifferentials and we relate the subdifferentials to known subdifferentials. We adapt the general duality schemes in terms of Lagrangians or in terms of perturbations to two specific problems. First a general mathematical programming problem and then a programming problem with linear constraints.
      PubDate: 2015-07-01
       
  • Optimization over the Pareto outcome set associated with a convex
           bi-objective optimization problem: theoretical results, deterministic
           algorithm and application to the stochastic case
    • Abstract: Abstract Our paper consists of two main parts. In the first one, we deal with the deterministic problem of minimizing a real valued function \(f\) over the Pareto outcome set associated with a deterministic convex bi-objective optimization problem (BOP), in the particular case where \(f\) depends on the objectives of (BOP), i.e. we optimize over the Pareto set in the outcome space. In general, the optimal value \(U\) of such a kind of problem cannot be computed directly, so we propose a deterministic outcome space algorithm whose principle is to give at every step a range (lower bound, upper bound) that contains \(U\) . Then we show that for any given error bound, the algorithm terminates in a finite number of steps. In the second part of our paper, in order to handle also the stochastic case, we consider the situation where the two objectives of (BOP) are given by expectations of random functions, and we deal with the stochastic problem \((S)\) of minimizing a real valued function \(f\) over the Pareto outcome set associated with this Stochastic bi-objective Optimization Problem (SBOP). Because of the presence of random functions, the Pareto set associated with this type of problem cannot be explicitly given, and thus it is not possible to compute the optimal value \(V\) of problem \((S)\) . That is why we consider a sequence of Sample Average Approximation problems (SAA- \(N\) , where \(N\) is the sample size) whose optimal values converge almost surely to \(V\) as the sample size \(N\) goes to infinity. Assuming \(f\) nondecreasing, we show that the convergence rate is exponential, and we propose a confidence interval for \(V\) . Finally, some computational results are given to illustrate the paper.
      PubDate: 2015-07-01
       
  • SymNMF: nonnegative low-rank approximation of a similarity matrix for
           graph clustering
    • Abstract: Abstract Nonnegative matrix factorization (NMF) provides a lower rank approximation of a matrix by a product of two nonnegative factors. NMF has been shown to produce clustering results that are often superior to those by other methods such as K-means. In this paper, we provide further interpretation of NMF as a clustering method and study an extended formulation for graph clustering called Symmetric NMF (SymNMF). In contrast to NMF that takes a data matrix as an input, SymNMF takes a nonnegative similarity matrix as an input, and a symmetric nonnegative lower rank approximation is computed. We show that SymNMF is related to spectral clustering, justify SymNMF as a general graph clustering method, and discuss the strengths and shortcomings of SymNMF and spectral clustering. We propose two optimization algorithms for SymNMF and discuss their convergence properties and computational efficiencies. Our experiments on document clustering, image clustering, and image segmentation support SymNMF as a graph clustering method that captures latent linear and nonlinear relationships in the data.
      PubDate: 2015-07-01
       
  • Heuristic rating estimation: geometric approach
    • Abstract: Abstract Heuristic rating estimation is a newly proposed method that supports decisions analysis based on the use of pairwise comparisons. It allows the ranking values of some alternatives (herein referred to as concepts) to be initially known, whilst ranks for other concepts have yet to be estimated. To calculate the missing ranks it is assumed that the priority of every single concept can be determined as the weighted arithmetic mean of the priorities of all the other concepts. It has been shown that the problem has an admissible solution if the inconsistency of the pairwise comparisons is not too high. The proposed approach adopts heuristics according to which a weighted geometric mean is used to determine the missing priorities. In this approach, despite increased complexity, a solution always exists and its existence does not depend on the inconsistency or reciprocity of the input matrix. Thus, the presented approach might be appropriate for a larger number of problems than previous methods. Moreover, it turns out that the geometric approach, as proposed in the article, can be optimal. The optimality condition is presented in the form of a corresponding theorem. A formal definition of the proposed geometric heuristics is accompanied by two numerical examples.
      PubDate: 2015-07-01
       
  • Characterizations of the solution set for quasiconvex programming in terms
           of Greenberg–Pierskalla subdifferential
    • Abstract: Abstract In convex programming, characterizations of the solution set in terms of the subdifferential have been investigated by Mangasarian. An invariance property of the subdifferential of the objective function is studied, and as a consequence, characterizations of the solution set by any solution point and any point in the relative interior of the solution set are given. In quasiconvex programming, however, characterizations of the solution set by any solution point and an invariance property of Greenberg–Pierskalla subdifferential, which is one of the well known subdifferential for quasiconvex functions, have not been studied yet as far as we know. In this paper, we study characterizations of the solution set for quasiconvex programming in terms of Greenberg–Pierskalla subdifferential. To the purpose, we show an invariance property of Greenberg–Pierskalla subdifferential, and we introduce a necessary and sufficient optimality condition by Greenberg–Pierskalla subdifferential. Also, we compare our results with previous ones. Especially, we prove some of Mangasarian’s characterizations as corollaries of our results.
      PubDate: 2015-07-01
       
  • Optimal curvature and gradient-constrained directional cost paths in
           3-space
    • Abstract: Abstract In the design of underground tunnel layout, the development cost is often dependent on the direction of the tunnel at each point due to directional ground fracturing. This paper considers the problem of finding a minimum cost curvature-constrained path between two directed points in 3-space, where the cost at every point along the path depends on the instantaneous direction. This anisotropic behaviour of the cost models the development cost of a tunnel in ground with faulting planes that are almost vertical. The main result we prove in this paper is that there exists an optimal path of the form \(\mathcal {C}\mathcal {S}\mathcal {C}\mathcal {S}\mathcal {C}\mathcal {S}\mathcal {C}\) (or a degeneracy), where \(\mathcal {C}\) represents a segment of a helix with unit radius and \(\mathcal {S}\) represents a straight line segment. This generalises a previous result that in the restriction of the problem to the horizontal plane there always exists a path of the form \(\mathcal {C}\mathcal {S}\mathcal {C}\mathcal {S}\mathcal {C}\) or a degeneracy which is optimal. We also prove some key structural results which are necessary for creating an algorithm which can construct an optimal path between a given pair of directed points in 3-space with a prescribed directional cost function.
      PubDate: 2015-07-01
       
  • On ergodic algorithms for equilibrium problems
    • Abstract: Abstract In this paper, we present a new iteration method for solving monotone equilibrium problems. This new method is based on the ergodic iteration method Ronald and Bruck in (J Math Anal Appl 61:159–164, 1977) and the auxiliary problem principle Noor in (J Optim Theory Appl 122:371–386, 2004), but it includes the usage of symmetric and positive definite matrices. The proposed algorithm is very simple. Moreover, it simplifies the assumptions necessary in order to converge to the solution. Specifically, whereas previous methods require strong monotonicity and Lipschitz-type continuous conditions, our proposed method only requires weak monotonicity conditions. Applications to the generalized variational inequality problem and some numerical results are reported.
      PubDate: 2015-06-28
       
  • The extended supporting hyperplane algorithm for convex mixed-integer
           nonlinear programming
    • Abstract: Abstract A new deterministic algorithm for solving convex mixed-integer nonlinear programming (MINLP) problems is presented in this paper: The extended supporting hyperplane (ESH) algorithm uses supporting hyperplanes to generate a tight overestimated polyhedral set of the feasible set defined by linear and nonlinear constraints. A sequence of linear or quadratic integer-relaxed subproblems are first solved to rapidly generate a tight linear relaxation of the original MINLP problem. After an initial overestimated set has been obtained the algorithm solves a sequence of mixed-integer linear programming or mixed-integer quadratic programming subproblems and refines the overestimated set by generating more supporting hyperplanes in each iteration. Compared to the extended cutting plane algorithm ESH generates a tighter overestimated set and unlike outer approximation the generation point for the supporting hyperplanes is found by a simple line search procedure. In this paper it is proven that the ESH algorithm converges to a global optimum for convex MINLP problems. The ESH algorithm is implemented as the supporting hyperplane optimization toolkit (SHOT) solver, and an extensive numerical comparison of its performance against other state-of-the-art MINLP solvers is presented.
      PubDate: 2015-06-25
       
  • Convexity with respect to families of sections and lines and their
           application in optimization
    • Abstract: Abstract The main goal of this paper is to introduce two generalized convexity notions, to examine their properties and their use in optimization theory, in particular, to deduce necessary and sufficient first order conditions.
      PubDate: 2015-06-24
       
  • Lower bound sets for biobjective shortest path problems
    • Abstract: Abstract This article considers the problem of calculating the set of all Pareto-optimal solutions in one-to-one biobjective shortest path problems with positive cost vectors. The efficiency of multiobjective best-first search algorithms can be improved with the use of consistent informed lower bounds. More precisely, the use of the ideal point as a lower bound has recently been shown to effectively increase search performance. In theory, the use of lower bounds that better approximate the Pareto frontier using sets of vectors (bound sets), could further improve performance. This article describes a lower bound set calculation method for biobjective shortest path problems. Improvements in search efficiency with lower bound sets of increasing precision are analyzed and discussed.
      PubDate: 2015-06-24
       
  • Gradient-constrained discounted Steiner trees II: optimally locating a
           discounted Steiner point
    • Abstract: Abstract A gradient-constrained discounted Steiner tree is a network interconnecting given set of nodes in Euclidean space where the gradients of the edges are all no more than an upper bound which defines the maximum gradient. In such a tree, the costs are associated with its edges and values are associated with nodes and are discounted over time. In this paper, we study the problem of optimally locating a single Steiner point in the presence of the gradient constraint in a tree so as to maximize the sum of all the discounted cash flows, known as the net present value (NPV). An edge in the tree is labelled as a b edge, or a m edge, or an f edge if the gradient between its endpoints is greater than, or equal to, or less than the maximum gradient respectively. The set of edge labels at a discounted Steiner point is called its labelling. The optimal location of the discounted Steiner point is obtained for the labellings that can occur in a gradient-constrained discounted Steiner tree. In this paper, we propose the gradient-constrained discounted Steiner point algorithm to optimally locate the discounted Steiner point in the presence of a gradient constraint in a network. This algorithm is applied to a case study. This problem occurs in underground mining, where we focus on the optimization of underground mine access to obtain maximum NPV in the presence of a gradient constraint. The gradient constraint defines the navigability conditions for trucks along the underground tunnels.
      PubDate: 2015-06-24
       
  • Gradient-constrained discounted Steiner trees I: optimal tree
           configurations
    • Abstract: Abstract A gradient-constrained discounted Steiner tree T is a maximum Net Present Value (NPV) tree, spanning a given set N of nodes in space with edges whose gradients are all no more than an upper bound m which is the maximum gradient. The nodes in T but not in N are referred to as discounted Steiner points. Such a tree has costs associated with its edges and values associated with its nodes. In order to reach the nodes in the tree, the edges need to be constructed. The edges are constructed in a particular order and the costs of constructing the edges and the values at the nodes are discounted over time. In this paper, we study the optimal tree configurations so as to maximize the sum of all the discounted cash flows, known as the NPV. An application of this problem occurs in underground mining, where we want to optimally locate a junction point in the underground access network to maximize the NPV in the presence of the gradient constraint. This constraint defines the navigability conditions on mining vehicles along the underground tunnels. Labellings are essential for defining a tree configuration and indicate gradients on the edges of the network. An edge in a gradient-constrained discounted Steiner tree is labelled as an f edge, an m edge or a b edge, if the gradient is less, equal or greater than m respectively. Each tree configuration is identified by the labellings of its edges. In this paper the non-optimal sets of labellings of edges that are incident with the discounted Steiner point in a gradient-constrained discounted Steiner network are classified. This reduces the number of configurations that need to be considered when optimizing. In addition, the gradient-constrained discounted Steiner point algorithm is outlined.
      PubDate: 2015-06-20
       
  • Maximizing the sum of a generalized Rayleigh quotient and another Rayleigh
           quotient on the unit sphere via semidefinite programming
    • Abstract: Abstract The problem is a type of “sum-of-ratios” fractional programming and is known to be NP-hard. Due to many local maxima, finding the global maximizer is in general difficult. The best attempt so far is a critical point approach based on a necessary optimality condition. The problem therefore has not been completely solved. Our novel idea is to replace the generalized Rayleigh quotient by a parameter \(\mu \) and generate a family of quadratic subproblems \((\hbox {P}_{\mu })'s\) subject to two quadratic constraints. Each \((\hbox {P}_{\mu })\) , if the problem dimension \(n\ge 3\) , can be solved in polynomial time by incorporating a version of S-lemma; a tight SDP relaxation; and a matrix rank-one decomposition procedure. Then, the difficulty of the problem is largely reduced to become a one-dimensional maximization problem over an interval of parameters \([\underline{\mu },\bar{\mu }]\) . We propose a two-stage scheme incorporating the quadratic fit line search algorithm to find \(\mu ^*\) numerically. Computational experiments show that our method solves the problem correctly and efficiently.
      PubDate: 2015-06-17
       
  • Erratum to: A box-constrained differentiable penalty method for nonlinear
           complementarity problems
    • PubDate: 2015-06-17
       
  • Notes on the single route lateral transhipment problem
    • Abstract: Abstract Previous research has analyzed deterministic and stochastic models of lateral transhipments between different retailers in a supply chain. In these models the analysis assumes given fixed transhipment costs and determines under which situations (magnitudes of excess supply and demand at various retailers) the transhipment is profitable. However, in reality, these depend on aspects like the distance between retailers or the transportation mode chosen. In many situations, combining the transhipments may save transportation costs. For instance, one or more vehicle routes may be used to redistribute the inventory of the potential pickup and delivery stations. This can be done in any sequence as long as the vehicle capacity is not violated and there is enough load on the vehicle to satisfy demand. The corresponding problem is an extension of the one-commodity pickup and delivery traveling salesman and the pickup and delivery vehicle routing problem. When ignoring the routing aspect and assuming given fixed costs, transhipment is only profitable if the quantities are higher than a certain threshold. In contrast to that, the selection of visited retailers is dependent on the transportation costs of the tour and therefore the selected retailers are interrelated. Hence the problem also has aspects of a (team) orienteering problem. The main contribution is the discussion of the tour planning aspects for lateral transhipments which may be valuable for in-house planning but also for price negotiations with external contractors. A mixed integer linear program for the single route and single commodity version is presented and an improved LNS framework to heuristically solve the problem is introduced. Furthermore, the effect of very small load capacity on the structure of optimal solutions is discussed.
      PubDate: 2015-06-14
       
  • Balancing mixed-model assembly lines with sequence-dependent tasks via
           hybrid genetic algorithm
    • Abstract: Abstract Close connections existing among sequence-dependent tasks should be emphasized while assembling products within automotive or electronic industries. This paper addresses the mixed-model assembly line balancing problem with sequence-dependent tasks with two objectives, the minimization of cycle time and workload variance. A hybrid genetic algorithm with novel logic strings was proposed to address the problem. First, both the sequence-dependent connections and precedence relations are integrated into the combined precedence graph so as to transform the original problem into the single-model assembly line balancing problem and to decrease the computational complexity. Second, three heuristic factors are hybridized into the process of initialization with the purpose of improving the quality of initial solution population. Third, considering sequence-dependent tasks, logic strings are designed to ensure the feasibility of chromosomes during two-point crossover and insertion mutation operations. Computational studies have demonstrated that the proposed algorithm can solve problems to near-optimality and even optimality with less computational effort.
      PubDate: 2015-06-10
       
  • Serial-batching scheduling with time-dependent setup time and effects of
           deterioration and learning on a single-machine
    • Abstract: Abstract This paper deals with serial-batching scheduling problems with the effects of deterioration and learning, where time-dependent setup time is also considered. In the proposed scheduling models, all jobs are first partitioned into serial batches, and then all batches are processed on a single serial-batching machine. The actual job processing time is a function of its starting time and position. In addition, a setup time is required when a new batch is processed, and the setup time of the batches is time-dependent, i.e., it is a linear function of its starting time. Structural properties are derived for the problems of minimizing the makespan, the number of tardy jobs, and the maximum earliness. Then, three optimization algorithms are developed to solve them, respectively.
      PubDate: 2015-06-07
       
 
 
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