Showing papers on "Discrete optimization published in 1985"

A Multiobjective Discrete Optimization Model for Land Allocation

Abstract: A multiobjective integer programming model is presented for allocating an area of land for development. The objectives considered in the allocation are cost, proximity to desirable and undesirable land features and the shape of the area. An interactive multiobjective optimization algorithm is presented and applied to the model. The algorithm generates a subset of efficient solutions with some guidance from the decision maker at each iteration as to what constitutes a "preferred" efficient point. The algorithm calls for the frequent solution of subproblems which constrain all but one of the objectives while optimizing the remaining one. In the land allocation model, the subproblems are integer programs solved efficiently by specialized enumeration techniques. For some of the subproblems namely, those using proximity as the single objective, the first feasible solution we enumerate is guaranteed optimal. For the other subproblems, we show that an algorithm with this fortunate property would require the solution of an NP-hard problem at each step of the enumeration. The model and algorithm were tested in locating potential sites for a 13-acre residential development within a 2250-acre study area near Norris, Tennessee.

A large scale machine loading problem in flexible assembly

Abstract: Flexible manufacturing is characterized by versatile work stations with minimum change over times and a versatile material handling system. The loading problem in flexible manufacturing is to assign tools, material, operations and jobs to work stations in order to minimize the total number of job-to-work station assignments. In this paper, we describe a special case of the general loading problem applied to flexible assembly and develop a discrete optimization model. We then discuss approaches for obtaining good heuristic solutions and present results for a large scale study.

Digital Control Systems: Theory, Hardware, Software

Abstract: Introduction continuous-time control-system response characteristics linear systems and the sampling process discrete systems modeling discrete control analysis discrete transform analysis (approximations) principles of signal conversion digital-control-system implementation random porocesses in digital control systems finite word length and compensator approach cascade compensation - digitization (DIG) cascade compensation - direct (DIR) technique feedback compensation discrete state-space design methods discrete quantitative feedback technique modern discrete control theory discrete optimal control discrete estimation and stochastic control. Appendices.

A survey of the perturbation analysis of discrete event dynamic systems

Abstract: This paper introduces an analysis and optimization technique for discrete event dynamic systems, such as flexible manufacturing systems (FMSs), and other discrete part production processes. It can also be used for enhancement of the simulation results of, or the monitoring of the operations of such systems in real time. Extensive references are given where readers may pursue futher details.

Optimal control using discrete Laguerre polynomials

Abstract: This paper presents discrete Laguerre polynomials which approximate the optimal control problems of digital systems. The discrete variational principle, in combination with the idea of a penalty function, is used to construct the modified discrete Euler-Lagrange equations. The discrete Laguerre series is then applied to simplify the modified equations into a set of linear algebraic ones for the approximate solutions of state and control variables. An example is given, and the results obtained are very accurate and attractive.

On the design of a sensitivity-reducing optimal dead-beat controller

Abstract: A method is proposed for the design of constant-gain feedback-control laws for linear multivariable discrete-time systems which reduce trajectory sensitivity to small system parameter variations and ensure the closed-loop eigenvalues at the origin The given quadratic index of performance including a sensitivity term is minimized in an average sense An efficient computational procedure based on direct cost optimization using gradient type algorithm is also reported An example is worked out to illustrate the proposed technique

A discrete optimization method of switched capacitor filters

Abstract: When constructed on a monolithic IC, switched capacitor filters (SCF's) composed of capacitors whose values are integer multiples of a unit value are desirable for miniaturization and reduction of power consumption, since high-precision capacitance ratios are realized using a small unit capacitance value. This paper describes a discrete optimization method of SCF. Variables which are effective to optimization are selected based on “normalized sensitivities,” which are sensitivities at a certain sampled frequency point divided by the absolute sum of sensitivities at all sampled frequency points. The min-max method which minimizes the maximum deviation is used to evaluate the optimization error. Initial discrete values of capacitances are determined by multiplying the pre-quantization capacitance by a positive constant and then minimizing the mean square error of their ratios. Finally, this optimization is applied to an 8th-order biquad bandpass filter and a 5th-order leapfrog lowpass filter and its effectiveness is confirmed.

On a discrete optimal control problem with incomplete information

Abstract: In the present paper multi-stage decision processes with incomplete information on time-dependent parameters are considered. For the discrete optimal control problem with incomplete information using a reduction operator, several different deterministic substitute problems are formulated. For the substitute problems necessary conditions for optimality are derived from the type of discrete maximum principle.