The continuous berth allocation problem (BAPC) solves the BAP with continuous berth space and continuous time to optimize the utilization of space and time of the ports.A non-linear programming (NLP) model is buil...
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The continuous berth allocation problem (BAPC) solves the BAP with continuous berth space and continuous time to optimize the utilization of space and time of the ports.A non-linear programming (NLP) model is built and an immune algorithm (IA) is proposed to solve *** effects of the number of vessels,the berth space length and the length of planning time are well controlled so that the approach can handle supper large-scale BAP with promising *** proposed model and algorithm can be embedded into berth scheduling modules to provide a fast and flexible solution for real-world BAPC to improve the port efficiency.
In most engineering applications, solutions derived from the lower-bound theorem of plastic limit analysis are particularly valuable because they provide a safe estimate of the load that will cause plastic collapse. A...
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In most engineering applications, solutions derived from the lower-bound theorem of plastic limit analysis are particularly valuable because they provide a safe estimate of the load that will cause plastic collapse. A solution procedure based on the meshless local Petrov-Galerkin (MLPG) method is proposed for lower-bound limit analysis. This is the first work for lower-bound limit analysis by this meshless local weak form method. In the construction of trial functions, the natural neighbour interpolation (NNI) is employed to simplify the treatment of the essential boundary conditions. The discretized limit analysis problem is solved numerically with the reduced-basis technique. The self-equilibrium stress field is constructed by a linear combination of several self-equilibrium stress basis vectors, which can be computed by performing an equilibrium iteration procedure during elasto-plastic incremental analysis. The non-linear programming sub-problems are solved directly by the Complex method and the limit load multiplier converges monotonically to the lower-bound of real solution. Several numerical examples are given to verify the accuracy and reliability of the proposed method for lower-bound limit analysis.
Recently, significant attention in compressed sensing has been focused on Basis Pursuit, exchanging the cardinality operator with the l(1)-norm, which leads to a linear formulation. Here, we want to look beyond using ...
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ISBN:
(纸本)9781424414833
Recently, significant attention in compressed sensing has been focused on Basis Pursuit, exchanging the cardinality operator with the l(1)-norm, which leads to a linear formulation. Here, we want to look beyond using the l(1)-norm in two ways: investigating non-linear solutions of higher complexity, but closer to the original problem for one, and improving known low complexity solutions based on Matching Pursuit using rollout concepts. Our simulation results concur with previous findings that once x is "sparse enough", many algorithms find the correct solution, but for averagely sparse problems we find that the l(1)-norm often does not converge to the correct solution - in fact being outperformed by Matching Pursuit based algorithms at lower complexity. The non-linear algorithm we suggest has increased complexity, but shows superior performance in this setting.
A multi-objective optimization technique for the operation of an irrigation reservoir is presented in this paper. The study deals with two different objective functions (OF): the minimization of reservoir release defi...
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A multi-objective optimization technique for the operation of an irrigation reservoir is presented in this paper. The study deals with two different objective functions (OF): the minimization of reservoir release deficit from the irrigation demand (OF1) and the maximization of net benefit by the demand sector (OF2). In the first step, monthly optimization of each individual objective was performed with a deterministic non-linear programming (NLP) algorithm, that gave the lower and upper bounds for the multi-objective analysis. In the second step, multi-objective optimization was performed through the Constraint method that operates by optimising the objective function OF1, while the other (OF2) was constrained to satisfy release strategies generated by the optimization. non-dominated set of release strategies is generated by parametrically varying the bounds of the constraints obtained from the individual optimal solutions. In the third step, the interactive analytical Step method was applied to find the best compromise solution, between the two OFs, by minimizing the distance of each non-dominated solution to an ideal solution that represents the utopian optimum for both OF1 and OF2. Furthermore, the interactive approach allows to improve the performance of the reservoir in terms of compromise irrigation releases, by changing the OF values until the satisfaction of predetermined criteria fixed by the planners and decision makers. The proposed water allocation model was applied to the Pozzillo reservoir operation, that supplies the Catania Plain irrigation area (Eastern Sicily).
The paper presents the topology and standard sizes optimization of a single-storey industrial steel building, made from standard hot rolled I sections. The structure consists of main portal frames, connected with purl...
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The paper presents the topology and standard sizes optimization of a single-storey industrial steel building, made from standard hot rolled I sections. The structure consists of main portal frames, connected with purlins. The structural optimization is performed by the Mixed-Integer non-linear programming approach (MINLP). The MINLP performs a discrete topology and standard dimension optimization simultaneously with continuous parameters. Since the discrete/continuous optimization problem of the industrial building is non-convex and highly non-linear, the Modified Outer-Approximation/Equality-Relaxation (OA/ER) algorithm has been used for the optimization. Alongside the optimum structure mass, the optimum topology with the optimum number of portal frames and purlins as well as all standard cross-section sizes have been obtained. The paper includes the theoretical basis and a practical example with the results of the optimization. (C) 2008 Journal of Mechanical Engineering. All rights reserved.
The paper starts giving the main results that allow a sensitivity analysis to be performed in a general optimization problem, including sensitivities of the objective function, the primal and the dual variables with r...
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The paper starts giving the main results that allow a sensitivity analysis to be performed in a general optimization problem, including sensitivities of the objective function, the primal and the dual variables with respect to data. In particular, general results are given for non-linear programming, and closed formulas for linearprogramming problems are supplied. Next, the methods are applied to a collection of civil engineering reliability problems, which includes a bridge crane, a retaining wall and a composite breakwater. Finally, the sensitivity analysis formulas are extended to calculus of variations problems and a slope stability problem is used to illustrate the methods. (C) 2008 Elsevier Ltd. All rights reserved.
Long-term financial transmission rights (FTRs) could be used to create incentives for small-scale transmission investments. However, these new investments may cause negative externalities on existing FTRs. Therefore t...
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Long-term financial transmission rights (FTRs) could be used to create incentives for small-scale transmission investments. However, these new investments may cause negative externalities on existing FTRs. Therefore the system operator needs a protocol for awarding incremental FTRs for new transmission capacity that maximize investors' preferences while simultaneously accounting for under-allocation of the existing network capacity by existing FTRs. To preserve revenue adequacy, the system operator calculates a minimum amount of currently unallocated FTRs (or proxy FTRs) that satisfies the power flow constraints in the existing network. The challenge is to define the proxy awards. Hogan proposes to define them as the best use of the current network along the same direction as the incremental FTR awards. This includes allowing positive or negative incremental FTR awards. In this paper we present an implementation through bi-level programming of Hogan's proposal for allocation of long-term FTRs and apply it to a radial line and one of Hogan's examples. Our results show that the simultaneous feasibility of the transmission investment depends on factors such as investor and preset proxy preferences, existing FTRs, and transmission capacity in both the existing network and all proposed expansions of it. (C) 2006 Elsevier B.V. All rights reserved.
This paper deals with the optimal selection of in out of n facilities to first perform in given primary jobs in Stage-1 followed by the remaining (n - m) facilities performing optimally the (n - m) secondary jobs in S...
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This paper deals with the optimal selection of in out of n facilities to first perform in given primary jobs in Stage-1 followed by the remaining (n - m) facilities performing optimally the (n - m) secondary jobs in Stage-II. It is assumed that in both the stages facilities perform in parallel. The aim of the proposed study is to find that set of in facilities performing the primary jobs in Stage-I for which the sum of the overall completion times of jobs in Stage-I and the corresponding optimal completion time of the secondary jobs in Stage-II by the remaining (n - m) facilities is the minimum. The developed solution methodology involves solving the standard time minimizing and cost minimizing assignment problems alternately after forbidding some facility-job pairings and suggests a polynomially bound algorithm. This proposed algorithm has been implemented and tested on a variety of test problems and its performance is found to be quite satisfactory. (C) 2006 Elsevier Ltd. All rights reserved.
I applied perspectives on operations research (OR) to propose a non-linear mathematical model, termed the APWs (allocation of pumping wells) model, to address problems associated with allocating pumping rates of a mul...
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I applied perspectives on operations research (OR) to propose a non-linear mathematical model, termed the APWs (allocation of pumping wells) model, to address problems associated with allocating pumping rates of a multi-well system for a brackish water reverse osmosis (BWRO) plant. In some and and inshore regions, feed water mostly preferred to exploit groundwater, owing to its easier desalted characteristic than seawater. However, the operations of most multi-well systems are always arbitrary, and we could not guarantee the strategies of operation might be optimal;additionally, the pumping quantity and quality variation of each well would all induce the unstable quality of feed water, and then lead to the problem of scaling. Though adding acid could treat the problem of scaling, the acidification, on the other hand, means the increasing cost and damage risk of a reverse osmosis (RO) system. Therefore, the overriding objective of this study is to decide the optimal allocating pumping rate among wells for a RO system on the premise of no acid added and under finite groundwater resources, to ensure feed water has no scaling potential and achieve marginal usage of groundwater resources. The APWs model tries to integrate engineering and management aspects to replace subjective operation of a multi-well system. Here, I apply scaling intensity (SI) proposed by literature that considered calcium carbonate (CaCO3), calcium sulfate (CaSO4) and silica (SiO2) as mainly potential scaling compounds in feed water to assess the scaling potential of a RO system. Besides, I present a solving algorithm for achieving the maximal SI with no scaling occurred. Moreover, I apply the proposed model to a case study in Taiwan by considering four-well system, to obtain optimal allocation with retaining the cleanest residual storage of whole groundwater resources, to avoid the waste of water resources. The results shown that through the assistance of OR technique, it could provide helpful info
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