Search results for "operation"
showing 10 items of 2969 documents
An Operator-Based Exact Treatment of Open Quantum Systems
2005
"Quantum mechanics must be regarded as open systems. On one hand, this is due to the fact that, like in classical physics, any realistic system is subjected to a coupling to an uncontrollable environment which influences it in a non-negligible way. The theory of open quantum systems thus plays a major role in many applications of quantum physics since perfect isolation of quantum system is not possible and since a complete microscopic description or control of the environment degrees of freedom is not feasible or only partially so" [1]. Practical considerations therefore force one to seek for a simpler, effectively probabilistic description in terms of an open system. There is a close physi…
Bayesian design in queues: An application to aeronautic maintenance
2007
We exploit Bayesian criteria for designing M/M/c//r queueing systems with spares. For illustration of our approach we use a real problem from aeronautic maintenance, where the numbers of repair crews and spare planes must be sufficiently large to meet the necessary operational capacity. Bayesian guarantees for this to happen can be given using predictive or posterior distributions.
Analysis of the renal transplant waiting list in the País Valencià (Spain).
2005
In this paper we analyse the renal transplant waiting list of the Pais Valencia in Spain, using Queueing theory. The customers of this queue are patients with end-stage renal failure waiting for a kidney transplant. We set up a simplified model to represent the flow of the customers through the system, and perform Bayesian inference to estimate parameters in the model. Finally, we consider several scenarios by tuning the estimations achieved and computationally simulate the behaviour of the queue under each one. The results indicate that the system could reach equilibrium at some point in the future and the model forecasts a slow decrease in the size of the waiting list in the short and mid…
On surrogating 0–1 knapsack constraints
1999
In this note, we present a scheme for tightening 0–1 knapsack constraints based on other knapsack constraints surrogating.
A Bayesian analysis of a queueing system with unlimited service
1997
Abstract A queueing system occurs when “customers” arrive at some facility requiring a certain type of “service” provided by the “servers”. Both the arrival pattern and the service requirements are usually taken to be random. If all the servers are busy when customers arrive, they usually wait in line to get served. Queues possess a number of mathematical challenges and have been mainly approached from a probability point of view, and statistical analysis are very scarce. In this paper we present a Bayesian analysis of a Markovian queue in which customers are immediately served upon arrival, and hence no waiting lines form. Emergency and self-service facilities provide many examples. Techni…
A tabu search algorithm for assigning teachers to courses
2002
In this paper we deal with the problem of assigning teachers to courses in a secondary school. The problem appears when a timetable is to be built and the teaching assignments are not fixed. We have developed a tabu search algorithm to solve the problem. The parameters involved in the algorithm have been estimated by using multiple regression techniques. The computational results, obtained on a set of Spanish secondary schools, show that the solutions obtained by this automatic procedure can be favourably compared with the solutions proposed by the experts.
ARC A computerized system for urban garbage collection
1993
In this paper we present ARC a computerized system developed for urban garbage collection. The package is intended to help the planners in the design of efficient collection routes and to facilitate the study and evaluation of alternatives concerning issues such as the type and number of vehicles, frequency of collection and type and location of refuse containers. The final product is a “user friendly” system designed to be used by the planners without outside assistance.
Validity of the electroneutrality and goldman constant-field assumptions in describing the diffusion potential for ternary electrolyte systems in sim…
1986
Abstract Three numerical algorithms capable of simulating transport processes through simple, porous membranes in the steady state have been employed in order to study the change in the diffusion potential with the membrane thickness and the ionic concentrations for the ternary systems NaClHClH20 and CaCI2NaC1H 2 O. The first simulation procedure uses Poisson's equation, the two others replace this equation by the electroneutrality and Goldman constant-field approximations respectively. From the results presented here, conditions for the applicability of the electroneutrality and constantfield assumption to ternary electrolyte systems are given.
[Fe(TPT)(2/3){M(I)(CN)2}2]⋅nSolv (M(I) = Ag, Au): new bimetallic porous coordination polymers with spin-crossover properties.
2013
Two new heterobimetallic porous coordination polymers with the formula [Fe(TPT)2/3{MI(CN)2}2]¿nSolv (TPT=[(2,4,6-tris(4-pyridyl)-1,3,5-triazine]; MI=Ag (nSolv=0, 1¿MeOH, 2¿CH2Cl2), Au (nSolv=0, 2¿CH2Cl2)) have been synthesized and their crystal structures were determined at 120¿K and 293¿K by single-crystal X-ray analysis. These structures crystallized in the trigonal R-3m space group. The FeII ion resides at an inversion centre that defines a [FeN6] coordination core. Four dicyanometallate groups coordinate at the equatorial positions, whilst the axial positions are occupied by the TPT ligand. Each TPT ligand is centred in a ternary axis and bridges three crystallographically equivalent Fe…
Synthesis, structure, and nuclease properties of several binary and ternary complexes of copper(II) with norfloxacin and 1,10 phenantroline
2007
Three new binary Cu(II) complexes of norfloxacin have been synthesized and characterized. We also report the synthesis, characterization and X-ray crystallographic structures of a new binary compound, [Cu(HNor)(2)]Cl(2).2H(2)O (2) and two new ternary complexes norfloxacin-copper(II)-phen, [Cu(Nor)(phen)(H(2)O)](NO(3)).3H(2)O (4), and [Cu(HNor)(phen)(NO(3))](NO(3)).3H(2)O (5). The structure of 2 consists of two crystallographically independent cationic monomeric units of [Cu(HNor)(2)](2+), chloride anions, and uncoordinated water molecules. The Cu(II) ion is placed at a center of symmetry and is coordinated to two norfloxacin ligands which are related through the inversion center. The struct…