A new methodology for sensitivity and stability analysis of analytic network models

In this paper we develop a methodology to study the sensitivity and the stability of models built using the Analytic Network Process. We study two types of stability: core and solution stability. The former deals with finding the region of the perturbation space in which the initial solution (i.e., the alternative that is ranked first) obtained from the ANP model remains most preferred. The latter deals with finding the regions of the perturbation space in which the solutions that were not initially most preferred (i.e., alternatives that were not ranked first) become most preferred (i.e., they are ranked first). The methodology consists of three stages: generation of the perturbation space, finding the boundaries of the regions in the perturbation space in which the different alternatives are ranked first, and finding the stability regions.     

Small Ball Probabilities Around Random Centers of Gaussian Measures and Applications to Quantization

Let be a centered Gaussian measure on a separable Hilbert space (E, ). We are concerned with the logarithmic small ball probabilities around a -distributed center X. It turns out that the asymptotic behavior of –log (B(X,)) is a.s. equivalent to that of a deterministic function _R (). These new insights will be used to derive the precise asymptotics of a random quantization problem which was introduced in a former article by Dereich, Fehringer, Matoussi, and Scheutzow.⁽⁸⁾     

高阶导数的插值公式

本文我们得到一种插值公式,它通过一系列点,且满足该点列上的初始高阶导数值.最后还给出这种插值公式的误差估计.     

Stable and transient color centers in Gd3Ga5O12 crystals

The work is devoted to investigation of stable color centers (CC) that are created in Gd₃Ga₅O₁₂ (GGG) crystals under irradiation with γ-quanta (E = 1.25 MeV, D = 10⁵ Gy ) as well as transient CC created in the crystals under irradiation with pulsed electron beam (E = 0.25 MeV, pulse duration 10 ns, fluence 10¹² cm^-2, time interval of registration 0-500 ns). On the basis of the performed study of optical absorption spectra of the as-grown and irradiated crystals it was established the correlation between a defect subsystem of as-grown crystals and a type of CC induced by radiation in the crystals. The role of Ca²⁺ dopant ions in the processes of CC formation is examined. Models of the stable and transient CC are proposed. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

光学活性螺-环丙烷双内酯化合物的合成

描述了5-(l-孟氧基)-3-溴-2(5H)-呋喃酮新手性试剂1与氮亲核试剂发生的串联不对称双Michael加成/分子内亲核取代反应,一举生成4个新手性中心。报道了含有叔胺官能团的螺-环丙烷双内酯化合物4a-4d的合成方法以及结构测定。     

Radiation-induced color centers in the near-surface layer of lithium fluoride crystals

For radiation-induced intrinsic color centers, we show that the concentrations of identical centers and the concentration ratios of different centers are quite different in the near-surface layer and within the interior volume of a lithium fluoride crystal. We have established that these differences also depend on the sign of the difference between the temperature at which the crystal was irradiated with γ photons and the vacancy mobility temperature. We provide an interpretation for the results obtained, based on the structural features of the near-surface layer and the concentration ratio of vacancies and electrons in the layer, serving as the starting components for color center formation. We found that the concentrations of centers change over the course of a few days by tens of percent in the layer “emerging” from the interior onto the surface as a result of cleavage of the crystal. We measured the luminescence lifetimes of F₃ (R2) and F₄ centers: 6.6 nsec and 11.7 nsec. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 775–781, November–December, 2006.     

Optimal control of parallel server systems with many servers in heavy traffic

We consider a parallel server system that consists of several customer classes and server pools in parallel. We propose a simple robust control policy to minimize the total linear holding and reneging costs. We show that this policy is asymptotically optimal under the many-server heavy traffic regime for parallel server systems when the service times are only server pool dependent and exponentially distributed. J.G. Dai’s research supported in part by National Science Foundation grants CMMI-0727400 and CNS-0718701, and by an IBM Faculty Award.     

Reduction of Cr(VI) Assisted by Sol-Gel Generated Electron-Hole Centers

We report an in-situ harvesting technique of electron-hole (e⁻-h⁺) carriers (e.g., the defect electrons in the O^{2 −} matrix and the self-trapped holes, Si–O⁻–Si) generated during sol-gel processing. In the absence of redox species, the e⁻-h⁺ centers created during room temperature sol-gel polycondensation steps are quickly annihilated and deactivated. However, when Cr(VI) ions are pre-dispersed in sol-gel solutions, the ejected electrons can be effectively harvested for the reduction of Cr(VI) to Cr(III) ions which are encapsulated in the silica gel matrix. The Cr(VI) ions, the possible intermediate oxidation states of chromium ions such as Cr(V) and/or Cr(IV), and the stable Cr(III)-hole complexes in the sol-gel matrix are investigated using uv-visible spectroscopy, electron paramagnetic resonance spectroscopy, and cyclic voltammetry. The chemical stability of Cr(VI) and Cr(III) in sol-gel networks is compared to that in aqueous solutions. The results indicate that the utilization of e⁻-h⁺ carriers generated in the sol-gel can be an effective and selective means for investigating the redox process of Cr(VI) and encapsulating the stable Cr(III) ions in the confined sol-gel environments.