Principles and Practice of Constraint Programming 

About: Principles and Practice of Constraint Programming is an academic conference. The conference publishes majorly in the area(s): Excited state & Ab initio. Over the lifetime, 11394 publications have been published by the conference receiving 250058 citations.

Self-consistent molecular Hartree—Fock—Slater calculations I. The computational procedure

Abstract: A numerical—variational computational scheme for performing self-consistent molecular MO LCAO calculations in the HFS model is presented. The local exchange approximation is used, but the usual muffin-tin approximation for potentials or densities is avoided. Procedures specifically optimized for treating large systems, such as transition-metal complexes, are developed. Some illustrative results are given for small molecules. We show that one-electron energies can be calculated rapidly and that the charge distribution is also easily obtained. Total energies, and therefore optim- ized molecular geometries, require more computation time.

Auxiliary basis sets to approximate Coulomb potentials

Abstract: We demonstrate accuracy and computational efficiency resulting from an approximate treatment of Coulomb operators which is based on the expansion of molecular electron densities in atom-centered auxiliary basis sets. This is of special importance in density functional methods which separate the treatment of Coulomb and exchange-correlation terms. Auxiliary basis sets are optimized as much as possible for isolated atoms and then augmented for use in molecular electronic structure calculations. For molecules involving atoms up to Br this typically affects energies by only 10−4 au per atom, and computed structure constants by less than 0.1 pm in bond distances and 0.1° in bond angles.

Approximate evaluations of the electrostatic free energy and internal energy changes in solution processes

Abstract: A recently proposed procedure for introducing solvent effects in the molecular hamiltonian of a solute is here re-elaborated to get approximate solutions of the corresponding classical electrostatic problem. The basic feature of the original procedure, i.e. the direct utilization of a quantum-mechanical ab initio description of the solute charge distribution in the “continuum” solution model, with cavities of arbitrary shape, is maintained. The meaning of supplementary assumptions introduced in classical calculation 0is discussed, and a comparison is made with analogous evaluations obtained with other approaches

STOPP (Screening Tool of Older Person's Prescriptions) and START (Screening Tool to Alert doctors to Right Treatment). Consensus validation.

Abstract: Objective Older people experience more concurrent illnesses, are prescribed more medications and suffer more adverse drug events than younger people. Many drugs predispose older people to adverse events such as falls and cognitive impairment, thus increasing morbidity and health resource utilization. At the same time, older people are often denied potentially beneficial, clinically indicated medications without a valid reason. We aimed to validate a new screening tool of older persons' prescriptions incorporating criteria for potentially inappropriate drugs called STOPP (Screening Tool of Older Persons' Prescriptions) and criteria for potentially appropriate, indicated drugs called START (Screening Tool to Alert doctors to Right, i.e. appropriate, indicated Treatment). Methods A Delphi consensus technique was used to establish the content validity of STOPP/START. An 18-member expert panel from academic centers in Ireland and the United Kingdom completed two rounds of the Delphi process by mail survey. Inter-rater reliability was assessed by determining the kappa-statistic for measure of agreement on 100 data-sets. Results STOPP is comprised of 65 clinically significant criteria for potentially inappropriate prescribing in older people. Each criterion is accompanied by a concise explanation as to why the prescribing practice is potentially inappropriate. START consists of 22 evidence-based prescribing indicators for commonly encountered diseases in older people. Inter-rater reliability is favorable with a kappa-coefficient of 0.75 for STOPP and 0.68 for START. Conclusion STOPP/START is a valid, reliable and comprehensive screening tool that enables the prescribing physician to appraise an older patient's prescription drugs in the context of his/her concurrent diagnoses.

Using Constraint Programming and Local Search Methods to Solve Vehicle Routing Problems

Abstract: We use a local search method we term Large Neighbourhood Search (LNS) to solve vehicle routing problems. LNS is analogous to the shuffling technique of job-shop scheduling, and so meshes well with constraint programming technology. LNS explores a large neighbourhood of the current solution by selecting a number of "related" customer visits to remove from the set of planned routes, and re-inserting these visits using a constraint-based tree search. Unlike similar methods, we use Limited Discrepancy Search during the tree search to re-insert visits. We analyse the performance of our method on benchmark problems. We demonstrate that results produced are competitive with Operations Research meta-heuristic methods, indicating that constraint-based technology is directly applicable to vehicle routing problems.