Computationally Efficient Methods for Calculating the Ideal Solution for MOLP Problems

This paper presents the results of an investigation into computational considerations that are relevant to large-scale multiobjective linear programming (MOLP) problems. Four approaches to obtaining a representation of the ideal solution are compared. Statistics on the number of simplex iterations and CPU time required are analysed for a set of randomly generated multiobjective linear programming problems. Recommendations are made based on the analysis of these results which are applicable to many MOLP solution algorithms.     

Medicinal Inventory Control in a University Health Centre

This paper presents a stochastic, periodic-review model used to control the medicine inventories in a university health centre. Features and formulation of the model are discussed in terms of the stockout objective and the budgetary constraint. Demand and cost data used for the three medicine groups are provided. Findings of the study are analysed within the framework of sensitivity analysis, where the expected shortage levels for the medicine groups studied are taken as the performance criteria.     

New Heterocyclic Phosphorus Ylides: Synthesis,Crystal Structure,and Theoretical Calculation of Alkyl Substituted 3-(4-Benzoyl-1,5-diphenyl-2,3-dihydro-1H-pyrazol-3-yl)-3-oxo-2-(triphenylphosphoranylidene) Propanoates

Novel alkyl substituted 3-(4-benzoyl-1,5-diphenyl-2,3-dihydro-1H-pyrazol-3-yl)-3-oxo-2-(triphenylphosphoranylidene) propanoates (3) were synthesized from 4-benzoyl-1,5-diphenyl-1H-pyrazole-3-carbonylchloride (1) and alkyl (triphenylphosphoranylidene) acetates (2a–b). The synthesized compounds were characterized by elemental analysis, spectroscopic studies (3a–b), and single crystal X-ray diffraction (3a). The mechanism of the reaction between (1) and (2a) was studied by AM1, and the geometrical parameters of the studied molecules were also carried out in B3LYP methods with the standard 6–31G (d,p) basis set. NBO analysis were studied for 1 and 2a B3LYP methods with the standard 6–31G (d,p) basis set.     

Hamilton’s principle and associated variational principles in polar thermopiezoelectricity

We express Hamilton’s principle for a regular region of thermopiezoelectric polar materials. First, we obtain a four-field variational principle which leads, as its Euler-Lagrange equations, to the divergence equations and the associated natural boundary conditions only. Next, we adjoin the rest of the fundamental equations into the variational principle through an involutory transformation. Thus, we formulate a differential type of unified variational principles operating on all the field variables. The unified variational principle is extended for the region with a fixed internal surface of discontinuity and for a curvilinear laminated region as well. The principles derived in invariant form are expressible in a system of particular coordinate system most appropriate to the geometry of the regions. They are indicated to recover some of earlier principles as special cases.     

The linear symmetries of Hill’s lunar problem

Archiv der Mathematik - A symmetry of a Hamiltonian system is a symplectic or anti-symplectic involution which leaves the Hamiltonian invariant. For the planar and spatial Hill lunar problem, four...