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1.
Vincent T’kindt Karima Bouibede-Hocine Carl Esswein 《4OR: A Quarterly Journal of Operations Research》2005,3(1):1-21
In this paper we tackle an important point of combinatorial optimisation: that of complexity theory when dealing with the counting or enumeration of optimal solutions. Complexity theory has been initially designed for decision problems and evolved over the years, for instance, to tackle particular features in optimisation problems. It has also evolved, more or less recently, towards the complexity of counting and enumeration problems and several complexity classes, which we review in this paper, have emerged in the literature. This kind of problems makes sense, notably, in the case of multicriteria optimisation where the aim is often to enumerate the set of the so-called Pareto optima. In the second part of this paper we review the complexity of multicriteria scheduling problems in the light of the previous complexity results.Received: November 2004 / Received version: March 2005MSC classification:
90B40, 90C29, 68Q15 相似文献
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Aicha Benabad Karima Bakhous Fatima Cherkaoui Elizabeth M. Holt 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):1292-1293
BiV0.4Fe3IIIO(PO4)3 crystallizes with two Fe atoms (one on an inversion centre and one on a mirror plane) displaying octahedral geometry and a third Fe atom (on a mirror plane) with trigonal bipyramidal coordination. Fe atoms are seen in oxygen‐bridged chains. BiV atoms are found in the interstitial sites between these chains. Bi shows sevenfold coordination, with Bi—O distances between 2.357 (7) and 2.529 (6) Å. 相似文献
4.
This paper studies pricing strategies in a market channel composed of one national brand manufacturer and two retailers who, each, carry their own store brand and a national brand products. The model accounts for product competition between store brands and the national brand products, as well as for store competition between retailers. 相似文献
5.
Ighilahriz K Boutemeur B Chami F Rabia C Hamdi M Hamdi SM 《Molecules (Basel, Switzerland)》2008,13(4):779-789
We have investigated a microwave-assisted synthesis of 4(3H)-quinazolinones by condensation of anthranilic acid, orthoesters (or formic acid) and substituted anilines,using Keggin-type heteropolyacids (H(3)PW(12)O(40).13H(2)O, H(4)SiW(12)O(40).13H(2)O,H(4)SiMo(12)O(40).13H(2)O or H(3)PMo(12)O(40).13H(2)O) as catalysts. We found that the the use of H(3)PW(12)O(40).13H(2)O acid coupled to microwave irradiation allows a solvent-free, rapid (approximately 13min) and high-yielding reaction. 相似文献
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Acid-promoted asymmetric sulfoxidations of prochiral sulfides using binaphthyl-derived oxaziridines have been studied. The reactions of dialkyl or aryl-alkyl sulfides gave good yields of the corresponding sulfoxides with enantiopurities ranging from 20% to 80%. The influence of temperature and strength of the acid catalyst on enantioselectivity was studied. The absolute configuration of the resulting major enantiomer varied with the structure of the sulfide. 相似文献
7.
This work is concerned with the existence of unbounded positive solutions for a second-order nonlinear three-point boundary
value problem on the positive half-line. The interesting points of the results are that the nonlinearity depends on the solution
and its derivative and may change sign. Moreover, it satisfies general polynomial growth conditions. New existence results
of nontrivial single and multiple positive solutions are proved using recent fixed point theorems on cones in a special Banach
space. 相似文献
8.
The aim of this paper is to study, for L
1-data, the absorption problem of parabolic type : with Dirichlet boundary conditions and initial conditions. Here a satisfies the classical Leray-Lions hypotheses and β(x, ·) is the subdifferential ∂j(x, ·), where j is a convex function such that j(·, 0) = 0. Existence and uniqueness of an entropy solution is established.
相似文献
9.
Microwave‐Assisted Synthesis of Arylazoaminopyrazoles as Disperse Dyes for Textile Printing 下载免费PDF全文
Tawfik A. Khattab Karima M. Haggag Mohamed H. Elnagdi Amal A. Abdelrahman Sherif Abdelmoez Aly 《无机化学与普通化学杂志》2016,642(13):766-772
The synthesis of heterocyclic azo‐dyes via conventional heating and microwave (MW) heating was investigated. From a sequence of reactions starting from cyanoacetic acid, 4‐arylazo‐2H‐pyrazol‐3‐ylamines and 4‐arylazo‐2‐phenyl‐2H‐pyrazol‐3‐ylamines were obtained. The structures these compounds were obtained by inspection of spectroscopic and analytical techniques including 1H and 13C NMR spectroscopy, IR spectroscopy, mass spectrometry, and elemental analysis. The fastness properties and UV/Vis absorption spectroscopic data of these disperse dyes in printing polyester fabrics were investigated. 相似文献
10.
Focusing on mitigation strategies for global pandemic influenza, we use elementary mathematical models to evaluate the implementation and timing of non-pharmaceutical intervention strategies such as travel restrictions, social distancing and improved hygiene. A spreadsheet model of infection spread between several linked heterogeneous communities is based on analytical calculations and Monte Carlo simulations. Since human behavior will likely change during the course of a pandemic, thereby altering the dynamics of the disease, we incorporate a feedback parameter into our model to reflect altered behavior. Our results indicate that while a flu pandemic could be devastating; there are coping methods that when implemented quickly and correctly can significantly mitigate the severity of a global outbreak. 相似文献