We consider linearprogramming (LP) models for metabolic networks in which alternate optima often arise, and need to be identified to allow for data interpretation or the effective design of follow-up experiments. A r...
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We consider linearprogramming (LP) models for metabolic networks in which alternate optima often arise, and need to be identified to allow for data interpretation or the effective design of follow-up experiments. A recursive mixed-integerlinearprogramming (MILP) algorithm is proposed for rigorously finding all alternate optima. The carbon trafficking alternatives of an Escherichia coli mutant lacking pyruvate kinase are analyzed with the proposed algorithm. The results are discussed in terms of using them as an input to isotopomer mapping matrix calculations in order to design C-13 NMR experiments for maximum contrast. (C) 2000 Elsevier Science Ltd. All rights reserved.
The problem considered in this paper deals with the short term scheduling of a two stage continuous process with intermediate storage tanks. The major scheduling decisions in this problem are: a) the assignment of ord...
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The problem considered in this paper deals with the short term scheduling of a two stage continuous process with intermediate storage tanks. The major scheduling decisions in this problem are: a) the assignment of orders to various storage tanks;b) the sequence of orders in each unit;c) the timing of various operations in different stages. The problem is highly combinatorial in nature. The major challenge is to develop strong integerprogramming formulations and to devise efficient solution techniques. An initial model is presented in the form of a disjunctive program which is later transformed to a mixed integer linear programming (MILP) problem. A number of example problems are solved which highlight the limitations of this model as the number of orders increases. A heuristic based on partial preordering is considered which solves industrial sized problems very quickly. The objective function values for the heuristic solutions are within 7% of the optimal values.
One of the key problems in hardware/software codesign is hardware/software partitioning. This paper describes a new approach to hardware/software partitioning using integerprogramming (IP). The advantage of using IP ...
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One of the key problems in hardware/software codesign is hardware/software partitioning. This paper describes a new approach to hardware/software partitioning using integerprogramming (IP). The advantage of using IP is that optimal results are calculated for a chosen objective function, The partitioning approach works fully automatic and supports multi-processor systems, interfacing and hardware sharing. In contrast to other approaches where special estimators are used, we use compilation and synthesis tools for cost estimation. The increased time for calculating values for the cost metrics is compensated by an improved quality of the values. Therefore, fewer iteration steps for partitioning are needed. The paper presents an algorithm using integerprogramming for solving the hardware/software partitioning problem leading to promising results.
This paper introduces an integrated dynamic optimization approach for nonrenewable energy (NRE) resources management under uncertainty. A hybrid inexact chance-constrained mixed-integerlinearprogramming (ICCMILP) me...
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This paper introduces an integrated dynamic optimization approach for nonrenewable energy (NRE) resources management under uncertainty. A hybrid inexact chance-constrained mixed-integerlinearprogramming (ICCMILP) method is proposed, with an objective of maximizing economic return under constraints of resources availability and environmental regulations. In its solution process, the ICCMILP is transformed into two deterministic submodels, which correspond to the upper and lower bounds for the desired objective function value. Interval solutions, which are feasible and stable in the given decision space, can then be obtained by solving the two submodels sequentially. Thus, decision alternatives can be generated by adjusting decision variable values within their solution intervals. The obtained solutions are useful for decision makers to optimally allocate limited NRE resources over time for acquiring maximized benefit. Meanwhile, regional air quality could be maintained to keep the communities from health damage. Results of a hypothetical case study indicate that reasonable solutions for dynamic planning of NRE resources allocation in a regional system have been obtained. A number of decision alternatives were generated based on the ICCMILP solutions as well as the projected applicable conditions. (C) 2000 Elsevier Science B.V. All rights reserved.
We consider linearprogramming (LP) models for metabolic networks in which alternate optima often arise, and need to be identified to allow for data interpretation or the effective design of follow-up experiments. A r...
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We consider linearprogramming (LP) models for metabolic networks in which alternate optima often arise, and need to be identified to allow for data interpretation or the effective design of follow-up experiments. A recursive mixed-integerlinearprogramming (MILP) algorithm is proposed for rigorously finding all alternate optima. The carbon trafficking alternatives of an Escherichia coli mutant lacking pyruvate kinase are analyzed with the proposed algorithm. The results are discussed in terms of using them as an input to isotopomer mapping matrix calculations in order to design C-13 NMR experiments for maximum contrast. (C) 2000 Elsevier Science Ltd. All rights reserved.
Arterial progression methods, adapted for application to grid networks, use mixed integer linear programming models for the maximization of the bandwidths. Due to the number of discrete variables involved, these metho...
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Arterial progression methods, adapted for application to grid networks, use mixed integer linear programming models for the maximization of the bandwidths. Due to the number of discrete variables involved, these methods are computationally demanding and inefficient when applied to large networks. This paper develops a fast heuristic procedure, which can be applied to both uniform and variable bandwidth optimization. The procedure uses the traffic characteristics of the network and involves an iterative decomposition into priority arterial sub-networks . This facilitates the determination of the optimal values for the integer variables and enables the application of bandwidth optimization methods to large-scale networks.
This paper study the general facility layout problem is studied. A mathematical model is proposed and the optimal plant layout obtained based on the minimisation of the connectivity cost. In particular, the model cons...
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This paper study the general facility layout problem is studied. A mathematical model is proposed and the optimal plant layout obtained based on the minimisation of the connectivity cost. In particular, the model considers different equipment orientations, distance restrictions, different equipment connectivity inputs and outputs, and space availability. Rectangular shapes, within a 2D plant continuous space, describe the equipment items. The problem is formulated as a mixedintegerlinear Problem (MILP) where binary variables are introduced to characterise topological choices and continuous variables describe the distances and locations involved. The applicability of the proposed formulation is illustrated via a representative example.
Activity Based Costing and Management are important topics in today's management accounting literature. While there has been much attention paid in the Activity Based Costing literature to customer profitability a...
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Activity Based Costing and Management are important topics in today's management accounting literature. While there has been much attention paid in the Activity Based Costing literature to customer profitability analysis, process improvement and product design, there has been far less notice taken of purchasing. In this paper we develop an Activity Based Costing approach for the determination of procurement strategies. Vendor selection using an Activity Based Costing approach is choosing the combination of suppliers for a given product group that minimizes the total costs associated with the purchasing strategy. To this end we develop a mathematical programming model where decisions involve the selection of vendors and the determination of order quantities. The system computes the total cost of ownership, thereby increasing the objectivity in the selection process and giving the opportunity for various kinds of sensitivity analysis.
This paper presents a simulation model to be used for water supply planning by a metropolitan water utility, Water supply operations for a single, monthly time step are formulated as a mixedintegerlinear program (or...
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This paper presents a simulation model to be used for water supply planning by a metropolitan water utility, Water supply operations for a single, monthly time step are formulated as a mixedintegerlinear program (or more simply, LP). The LP is then embedded in a month-by-month simulation model, The LP is formulated using a priority-based objective function, The model has been used successfully by the Alameda County Water District (California) staff for its long-range, integrated planning. The model also shows that some of the inherent weaknesses of math programming in general and mixed integer linear programming in particular, can be overcome to build a successful model.
mixed integer linear programming models are presented to develop a schedule for the mining of precious metal from available deposits. Alternate formulations and branch-and-bound search strategies are discussed. LINGO ...
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mixed integer linear programming models are presented to develop a schedule for the mining of precious metal from available deposits. Alternate formulations and branch-and-bound search strategies are discussed. LINGO was used to build and solve the models. (C) 1999 Elsevier Science Ltd. All rights reserved.
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