Solution of discrete optimal control problems via mathematical programming

In this paper we consider the solution of discrete optimal control problems via mathematicalprogramming. In particular we examine iterative schemes, such as Hestenes' method of multipliers and interior-point method, which are suitable for linear-quadratic optimal control problems and for nonlinear optimal control problems respectively. Convergence results are reported as well as numerical evaluation of the effectiveness of these methods

Nonlinear programming methods for solving optimal control problems

This paper concerns with the problem of solving optimal control problems by means of nonlinear programming methods. The technique employed to obtain a mathematical programming problem from an optimal control problem is explained and the Newton interior-point method, chosen for its solution, is presented with special regard to the choice of the involved parameters. An analysis of the behaviour of the method is reported on four optimal control problems, related to improving water quality in an aeration process and to the study of diffusion convection processes

Numerical solution of discrete quadratic optimal control problems

This paper is concerned with the development of the Hestenes' method of multipliers combined with the conjugate gradient algorithm for solving discrete quadratic optimal control problems. This method is well suitable for parallel implementation on vector-parallel computers. Conditions for the convergence of the method are established and results of computational experiments, which are aimed at evaluating the effectiveness of the method, are reported

Upper limb disability in hemodialysis patients: evaluation of contributing factors aside from amyloidosis.

This cross-sectional case-control study evaluated upper limb muscle strength and shoulder mobility in hemodialysis (HD) patients with arteriovenous fistula or graft. Twenty-five adult patients on thrice-a-week HD treatment for 6 months at least, were selected for the study. In all the patients and control subjects, handgrip tests and tests of range of motion in the upper extremities were evaluated by physiotherapy tests. Patients on HD showed lower muscle strength than age and sex matched subjects without severe chronic kidney disease (right: 30.1 ± 11.6 vs 40.5 ± 15.1 kg, P < 0.001; left 29.1 ± 12.9 vs 40.7 ± 11.1 kg, P < 0.01), and a reduced range of shoulder mobility. The presence of fistula or graft was associated with a greater limitation of both active (74.0 ± 18.3 vs 85.2 ± 8.8 °, P < 0.01) and passive (82.2 ± 9.9 vs 87.2 ± 6.6 °, P < 0.05) extra-rotation than the contralateral limb, with a higher prevalence of impingement (72 vs 36%, P < 0.05). Muscle strength was related to albumin and inversely to age; whereas β(2) -microglobulin and CRP serum levels were associated with impairment of passive and active extra-rotation of the shoulder that was free from the fistula or graft. In summary, patients on HD have a reduced range of shoulder mobility and marked reduction of muscle strength. The abnormalities are more prevalent in upper limbs with fistula or grafts. The arteriovenous fistula or graft may worsen the disability of the patient's upper limbs presumably due to the obligate position required during the HD sessions. Proper pre- and post-dialysis exercise programs should be implemented to maintain mobility and strength of the upper limbs

The impact of the melting layer on the passive microwave cloud scattering signal observed from satellites: A study using TRMM microwave passive and active measurements

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