This paper presents the implementation of a new method in calculating the optimal unit commitment and economic dispatch of industrial enterprises with its own energy supply system, mostly with CHP-plants. To yield the...
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This paper presents the implementation of a new method in calculating the optimal unit commitment and economic dispatch of industrial enterprises with its own energy supply system, mostly with CHP-plants. To yield the most synergetic effects, both the marketplace and the demand of disposable industrial processes are taken into account. Because of the complexity of the formulated mathematical model and, thus, of the optimization problem, a new dynamic search strategy (DSS) based on mixed integer linear programming (MILP) is presented. With DSS, a considerable acceleration of calculation time could be achieved.
The cyclotomic polynomial (CP) prefilter design problem is formulated as an optimization problem with linear objective functions by applying the logarithm to the transfer function of the CP prefilter. Then this proble...
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ISBN:
(纸本)0780331923
The cyclotomic polynomial (CP) prefilter design problem is formulated as an optimization problem with linear objective functions by applying the logarithm to the transfer function of the CP prefilter. Then this problem is solved by mixed integer linear programming (MILP). Design examples demonstrate that this method leads to more efficient cascaded FIR prefilter-equalizers than existing methods.
We propose an optimal design method for digital IIR filters with powers-of-two coefficients. This method is based upon the formulation of a linear optimization problem that minimizes the filter's complexity for gi...
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We propose an optimal design method for digital IIR filters with powers-of-two coefficients. This method is based upon the formulation of a linear optimization problem that minimizes the filter's complexity for given specifications. It is shown that by taking the logarithm to the transfer function of cascade-form IIR filters, the design problem becomes linear and can be solved by mixed integer linear programming (MILP). Design examples are presented to demonstrate the efficiency of the proposed method.
In this paper, a mathematical model is developed that facilitates daily production scheduling in a tobacco processing plant. The implied objectives are to meet specific horizon production targets (obtained from a mast...
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In this paper, a mathematical model is developed that facilitates daily production scheduling in a tobacco processing plant. The implied objectives are to meet specific horizon production targets (obtained from a master production schedule), to maintain safety stock requirements and to ensure that the demand for labour lies within given limits. The express objective is to minimise the number of machines used in the production process. Additionally, the model incorporates work-in-progress, aspects of the demand for product transportation within the plant and machine capacity (utilisation) reduction effects associated with production sequencing. These aspects are relevant when dealing with time intervals as small as a day but can be averaged out when dealing with monthly time intervals. The developments in this paper represents stage II of the modelling of the tobacco plant, where stage I (already completed) was centred on obtaining a monthly master production schedule for a year ahead and assisting in macro planning activities. This paper also sees the development of a simple user-friendly heuristic which facilitates production sequencing on a daily basis given the master production schedule obtained from Stage I.
In this paper a two-dimensional trim-loss problem connected to the paper-converting industry is considered. The problem is to produce a set of product paper rolls from larger raw paper rolls such that the cost for was...
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In this paper a two-dimensional trim-loss problem connected to the paper-converting industry is considered. The problem is to produce a set of product paper rolls from larger raw paper rolls such that the cost for waste and the cutting time is minimized. The problem is generally non-convex due to a bilinear objective function and some bilinear constraints, which give rise to difficulties in finding efficient numerical procedures for the solution. The problem can, however, be solved as a two-step procedure, where the latter step is a mixed integer linear programming (MILP) problem. In the present formulation, both the width and length of the raw paper rolls as well as the lengths of the product paper roils are considered variables. All feasible cutting patterns are included in the problem and global optimal cutting patterns are obtained as the solution from the corresponding MILP problem. A numerical example is included to illustrate the proposed procedure. (C) 1998 Elsevier Science B.V.
This paper presents an integrated mathematical programming formulation of the manufacturing cell formation problem introduced by Nagi et al. The formulation incorporates critical production planning issues that includ...
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This paper presents an integrated mathematical programming formulation of the manufacturing cell formation problem introduced by Nagi et al. The formulation incorporates critical production planning issues that include long-term projected production requirements, resource capacity constraints, functionally identical machines and alternative process plans in the cell formation problem, with a common objective of minimizing the resulting intercell material handling effort. This problem is NP-hard. The previous work presented a heuristic solution based on decomposing the integrated problem into capacitated route selection and cell formation sub-problems that are solved iteratively until convergence. Like all fast heuristics, the method may suffer from poor solution quality, and non-heuristic methods cannot address problems of typical industrial dimensions because they would require exorbitant amounts of computing time. To overcome both these deficiencies, this paper (i) presents a 0-1 mixed integer linear programming (MILP) formulation alternative to the integrated cell formation problem, (ii) based on this formulation, develops a branch-and-bound procedure that provides improved solutions compared to those obtained by the heuristic of Nagi et al. (1990), and (iii) makes possible derivation of lower bounds to assess the quality gap when optimal solutions are unavailable or require excessive computing time. This work is important because it allows for better solutions to realistic industrial-sized problem instances.
A production optimization problem concerned with the paper-converting industry is considered in the present paper. The problem can be written as a cost minimization or as a profit maximization problem. The problem is ...
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A production optimization problem concerned with the paper-converting industry is considered in the present paper. The problem can be written as a cost minimization or as a profit maximization problem. The problem is to produce a set of product paper reels from larger raw paper reels such that certain specifications are satisfied, while the overall objective function is minimized/maximized. In this formulation, both the widths and lengths of the different raw paper used are utilized as variables. The lengths as well as the ordered amounts of the product paper reels are allowed to vary within certain specified limits. In addition to the trim-loss constraints, constraints for the simultaneous sequential scheduling of the cutting machines is also included, giving time constraints for the cutting machines in the considered formulation. The income from the product paper and overproduction as well as costs derived from the raw paper used, machine time, format changes as well as knife changes are all included in the objective function. A numerical example from the paper-converting industry under consideration is included to illustrate the proposed procedure.
The strategic decision to integrate Advanced Manufacturing Systems (AMS) within a traditional production system has become an attractive and sometimes necessary alternative in many industrial settings. The purpose of ...
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The strategic decision to integrate Advanced Manufacturing Systems (AMS) within a traditional production system has become an attractive and sometimes necessary alternative in many industrial settings. The purpose of this paper is to develop a model that focuses on this particular decision-making problem. Simplifications and approximations introduced at the operational level permit two key issues to be addressed: (1) where should AMS be implemented;and (2) when should this implementation occur. The model is shown to have good structure for a simplified analysis, thus making it particularly useful in instances where only rough estimates of costs are available and extensive 'what if' type analyses are therefore required.
This paper presents a mixed integer linear programming formulation for load-side control of electrical energy demand. The formulation utilizes demand prediction to determine if control actions are necessary, and it sc...
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This paper presents a mixed integer linear programming formulation for load-side control of electrical energy demand. The formulation utilizes demand prediction to determine if control actions are necessary, and it schedules both shedding and restoration times based on an optimization model that minimizes the net cost of load shedding. Operational constraints are satisfied through the use of minimum/maximum uptimes/downtimes, which depend upon the current state of the system. The algorithm is evaluated using a simulation model of an underground coal mining operation where, (i) its performance is compared with a traditional static, priority-based, load-shedding schedule, and, (ii) its potential is established for producing net savings through demand control.
The trim-loss problem appears when a customer's demand is to be satisfied in a paper converting mill. A set of product paper reels need to be cut from raw-paper reels. The problem is by nature an integer problem a...
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The trim-loss problem appears when a customer's demand is to be satisfied in a paper converting mill. A set of product paper reels need to be cut from raw-paper reels. The problem is by nature an integer problem and therefore gives rise to a difficult combinatorial problem. Maybe the most difficult problem beside. the combinatorics, is the fact that the paper converting mill needs to adapt itself to both the customer specified widths and the raw paper widths that are delivered from a raw paper mill. This fact makes it difficult to avoid material losses during the process. In the present paper some key issues are considered as to the combining the paper mill and the paper converting mill. (C) 1998 published by Elsevier Science Ltd. All rights reserved.
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