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1.
The problem of rerostering nurse schedules arises in hospitals when at least one nurse informs that she will be unable to perform the shifts assigned to her on one or more future work days. As a result, the current roster must be rebuilt in accordance with labour contract rules and institutional requirements. All such restraints are regarded as hard constraints. However, major alterations in the previously assigned nurse schedules must be avoided. This paper is based on a case study of a public hospital in Portugal. It presents two new integer multicommodity flow formulations for the rerostering problem, besides a computational experiment performed using real data. The first model is based on a directed multilevel acyclic network. The aggregation of nodes in this network led to the second model. The results obtained show that the second integer multicommodity flow formulation outperforms the first, both in terms of solution quality, as well as in computational time. 相似文献
2.
The part families with precedence constraints problem (PFP) arises in industry, when flexible manufacturing systems are designed within a group technology approach. The aim of this problem is to arrange parts into families by imposing capacity constraints, concerning both the number of parts and processing times, besides precedence constraints in the building of families. 相似文献
3.
E. G. Boos D. I. Ermilova V. V. Samoilov T. Temiraliev B. V. Batyunya I. V. Boguslavsky N. B. Dashian I. M. Gramenitsky R. Lednický S. V. Levonian V. Vrba Z. Zlatanov E. Hannula P. Villanen J. Patočka R. K. Dementiev I. A. Korzhavina E. M. Leikin A. G. Pyzyrny V. I. Rud L. A. Tikhonova I. Herynek M. Lokajíček J. Řídký V. Šimák M. Suk A. Valkárová A. M. Khudzhadze G. O. Kuratashvili T. P. Topuriya V. D. Tsintsadze 《Zeitschrift fur Physik C Particles and Fields》1982,15(4):287-291
The 22.4 GeV/c \(\bar p\) p interactions with the leading particle and the slow proton subtracted are used as data on soft processes. Considerable similarity between them and hard processes, such ase + e ? annihilation into hadrons, is found by means of studying charged multiplicities, KNO scaling and longitudinal as well as transverse spectra. 相似文献
4.
Propagation of SH waves in an irregular monoclinic crustal layer 总被引:2,自引:0,他引:2
A. Chattopadhyay S. Gupta V. K. Sharma Pato Kumari 《Archive of Applied Mechanics (Ingenieur Archiv)》2008,78(12):989-999
The present paper discusses the dispersion equation for SH waves in a monoclinic layer over a semi-infinite elastic medium
with an irregularity. In the absence of the irregularity, the dispersion equation reduces to standard dispersion equation
for SH waves in a monoclinic layer over an isotropic semi-infinite medium. The dispersion curves for different size of the
irregularity are computed and compared for the half-space without any irregularity. It can be seen that the phase velocity
is strongly influenced by the wave number and the depth of the irregularity. 相似文献
5.
A. Chattopadhyay S. Gupta V.K. Sharma Pato Kumari 《International Journal of Solids and Structures》2009,46(17):3241-3256
The reflection and refraction pattern of elastic waves at a corrugated interface between two triclinic half-spaces is discussed. The incident wave is taken to be the cause of the interface disturbance and the reflected and refracted waves are effects. This leads to the causality requirement that the reflected and refracted waves must propagate away from the interface. Closed form expressions of reflection and transmission coefficients are derived using Rayleigh’s method of approximation. The formulae of reflection and transmission coefficients are derived in closed form for the first-order approximation of the corrugation. The analytical expressions of all the three phase velocities of qP, qSV and qSH waves have been derived. The variation of reflection and refraction coefficients with the angle of incidence and also with the corrugation parameter is shown. In this paper we have developed Graphical User Interface (GUI) Software in MATLAB which shows the variation of reflection and refraction coefficients with respect to incident angle and corrugation parameter. This software can be generalized to show the variation of reflection and refraction coefficients. Numerical computations are performed for a scientific model and the results obtained are shown graphically. 相似文献
6.
Propagation of torsional waves in an inhomogeneous layer over an inhomogeneous half-space 总被引:1,自引:0,他引:1
The present paper is concerned with the study of propagation of torsional waves in an inhomogeneous isotropic layer whose
material properties vary harmonically with a space variable, lying over a semi-infinite inhomogeneous isotropic half-space.
The closed form solutions for the displacement in the layer and half-space are obtained separately. The dimensionless phase
velocity has been plotted against dimensionless wave number and scaled wave number for different values of inhomogeneity parameters.
The effects of inhomogeneity have been shown in the dispersion curves using 2D and 3D plot. 相似文献
7.
P. P. Monteiro H. L. Castro J. Castro R. Luí s D. Fonseca J. Pedro L. Pellegrino M. Hajduczenia S. Pato N. Garcia C. Santiago T. Silveira A. Ferreira 《Fiber and Integrated Optics》2005,24(3):395-410
This article summarizes the research activities carried out by the R&D Optical Networks Communications group (COM RD1), at Siemens S.A., in collaboration with both universities and other research institutes. These activities cover various aspects of advanced modulation formats, all optical wavelength conversion, optical quality of signal monitoring in transparent WDM networks, routing, and wavelength assignment in optical networks. 相似文献
8.
Aliano Filho Angelo de Oliveira Florentino Helenice Pato Margarida Vaz Poltroniere Snia Cristina da Silva Costa Joo Fernando 《Annals of Operations Research》2022,314(2):347-376
Annals of Operations Research - This work proposes a binary nonlinear bi-objective optimization model for the problem of planning the sustainable cultivation of crops. The solution to the problem... 相似文献
9.
E. G. Boos V. V. Samojlov Zh. S. Takibaev M. A. Tashinov T. Temiraliev B. V. Batyunya I. V. Boguslavsky N. A. Buzdavina I. M. Gramenitsky V. G. Ivanov R. Lednický L. A. Tikhonova A. Valkárová V. Vrba Z. Zlatanov I. Ervanne S. Ljung R. Orava H. Villanen P. Villanen J. Patočka B. V. Korolev Ya. M. Selektor V. N. Shulyachenko V. F. Turov P. K. Dementiev E. M. Lejkin A. G. Pavlova N. A. Pozhidaeva V. T. Rud L. Rob J. Záček J. Böhm J. Chýla J. Cvach I. Herynek P. Reimer J. Sedlák V. šimák 《Czechoslovak Journal of Physics》1976,26(11):1281-1289
The inclusive spectra for ¯pp collisions at 22·4 GeV/c are investigated. The transversal momentum distribution resembles the corresponding one in high energy pp interactions. The cross section in the central region is 28±mb. They
*-distribution of secondary particles in the central region indicates a charge asymmetry with the asymmetry parameter having the value 0.15±0·01. The upper limit of the diffraction dissociation of the beam particle is estimated to be
mb.The authors want to express their gratitude to the staff responsible for the operation of the Serpukhov accelerator and of the beam channel no. 9 and to the technical staff of the LUDMI-LA HBC. We also thank the technicians and assistants at all laboratories for their excellent work. The authors from the Moscow State University want to express their gratitude to Prof. V. G.Shevchenko for his continuous support of this work. 相似文献
10.
2,5-Dideoxy-2,5-imino-D-glucitol (DGDP) has been synthesized via the tin(II)-mediated anti-selective aldol reaction of bislactim ether 5 and a 3-O-silylated 2,4-ethylidene-D-erythrose derivative 6. In accordance with density functional theory calculations (at the B3LYP/cc-pVDZ-PP level), pericyclic transition structures with a boat-like conformation and a stabilizing hydrogen bond can account for the unexpected stereoselectivity. 相似文献