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871.
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Daniel S. Yeung Wing W. Y. Ng Aki P. F. Chan Patrick P. K. Chan Michael Firth Eric C. C. Tsang 《系统科学与系统工程学报(英文版)》2007,16(2):166-180
Company bankruptcies cost billions of dollars in losses to banks each year. Thus credit risk prediction is a critical part of a bank's loan approval decision process. Traditional financial models for credit risk prediction are no longer adequate for describing today's complex relationship between the financial health and potential bankruptcy of a company. In this work, a multiple classifier system (embedded in a multiple intelligent agent system) is proposed to predict the financial health of a company. In our model, each individual agent (classifier) makes a prediction on the likelihood of credit risk based on only partial information of the company. Each of the agents is an expert, but has limited knowledge (represented by features) about the company. The decisions of all agents are combined together to form a final credit risk prediction. Experiments show that our model out-performs other existing methods using the benchmarking Compustat American Corporations dataset. 相似文献
874.
1 Results Starch is considered a suitable source material because of its inherent biodegradability,ready viability and relatively low cost[1].In the present work,polymer electrolytes based on starch have been prepared by the solution cast technique.The conductivity of the films is characterized using impedance spectroscopy at room temperatures.The imaginary impedance (Zi) versus real impedance (ZR) plot of pure starch films consists of a semicircle.The bulk resistance (Rb) was taken from the intercept o... 相似文献
875.
1 Results Transition metal-catalyzed [2 2 2] cycloaddition is one of the most efficient protocols for the construction of six-membered ring system.Our group has comprehensively studied various types of highly enantioselective [2 2 2] cycloaddition for the synthesis of chiral cycloadducts; we already reported an iridium-catalyzed intermolecular [2 2 2] cycloaddition between α,ω-diynes,having various tethers and substituents on the alkyne termini,and monoalkynes,possessing oxygen or/and nitrogen functiona... 相似文献
876.
LU Li S. MCKENNA-LAWLOR S. BARABASH LIU ZhenXing CAO JinBin J. BALAZ K. KUDELA T. L. ZHANG C. M. CARR 《科学通报(英文版)》2007,52(12):1719-1723
The NUADU (NeUtral Atom Detector Unit) instrument aboard TC-2 recorded 4л solid angle images of charged particles (E >180 keV) spiraling around the magnetic field lines in the near-Earth plasma sheet (at ~ -7 RE, equatorial dawn-to-night side) during a geomagnetic storm (Dst =-219 nT) on August 24, 2005. Energetic ion beam events characterized by symmetrical, ring-like, solid angle distributions around ambient magnetic field lines were observed during a 34-minute traversal of the plasma sheet by the TC-2 spacecraft. Also, observations during these multiple crossings of the plasma sheet were monitored by the magnetometer experiment (FGM) aboard the same spacecraft. During each crossing, a whistler-mode chorus enhancement was observed in the anisotropic area by the TC-2 low frequency electromagnetic wave detector (LFEW/TC-2) at a frequency just above that of the local lower hybrid wave. A comparison of the ion pitch angle distribution (PAD) map with the ambient magnetic field shows that an enhancement in the field aligned energetic ion flux was accompanied by tailward stretching of the magnetic field lines in the plasma sheet. In contrast, the perpendicular ion-flux enhancement was accompanied by a signature indicating the corresponding shrinkage of the magnetic field lines in the plasma sheet. Since both parallel ion-flux and perpendicular ion-flux enhancements occurred intermittently, the data were interpreted to imply a dynamical, oscillatory process of the magnetic field line (stretching and shrinking) in the near-Earth plasma sheet, which might have acted to help establish an interaction region in this area which would support continuous aurora-substorm triggering during the ongoing magnetic storm. The whistler-mode chorus may have been produced due to ion gyro-resonance during particle pitch angle diffusion after the plasma sheet compression. 相似文献
877.
K.G. Subramanian R. Saravanan M. Geethalakshmi P. Helen Chandra M. Margenstern 《自然科学进展》2007,17(4):479-485
Array P systems were introduced by Paun Gh. which is linking the two areas of membrane computing and picture grammars. Puzzle grammars were introduced by us for generating connected picture arrays in the two-dimensional plane, motivated by the problem of tiling the plane. On the other hand, incorporating into arrays the developmental type of generation used in the well-known biologically motivated L systems, Siromoney and Siromoney proposed a very general rectangular array generating model, called extended controlled tabled L array system (ECTLAS). In this paper we introduce two variations of the array P system, called BPG array P system and parallel array P system. The former has in the regions array objects and basic puzzle grammar rules (BPG), which are a specific kind of puzzle grammar rules. In the latter, the regions have rectangular array objects and tables of context-free rules. We examine these two types of P systems for their array generative power. 相似文献
878.
Qiu Baoli Susan A. Coats Ren Shunxiang Ali M. Idris Xu Caixia Judith K. Brown 《自然科学进展》2007,17(6):645-654
Phylogenetic relationships for Bemisia tabaci were reconstructed by analysis of a ~780 bp fragment of the mitochondrial cytochrome oxidase I (mtCOI) gene with an emphasis on geographic range and distribution among eight eudicot plant families that are common hosts of B. tabaci worldwide to elucidate key phylogeographic linkages between populations extant in China (n=31) and India (n=34). Bootstrap values for the Maximum Parsimony tree were highly robust for all major nodes involving the major Asian clade, subgroups, and sister groups within, at 92%—100%. Between-clade distances for the Southeast Asia and three other major clades, e.g. from sub-Sahara Africa, North Africa-Mediterranean, and the Americas, were approximately >16% divergent. Two major Asian subgroups (I, II) were resolved, which represented populations indigenous to the region, comprising two (I a, I b) and five (II a—e) sister groups, respectively, which diverged by 11%. Two distinct populations from sunflower in Hyderabad grouped separately within the two Asian subgroups. All other populations grouped uniquely within Asian subgroup II or I. The “B” biotype was identified in 23 collections from China at 97.3%—99.5% nucleotide identity with “B” biotype reference sequences; it was not identified in collections from India. The majority of haplotypes were associated with 3—4 plant families, with one exception that for sister group IId (sesame, India), it might be monophagous. Thus, B. tabaci from the southeastern and near eastern regions of the Asian continent comprise of a large number of ancestral, richly divergent, mostly polyphagous populations. This region is therefore hypothesized to constitute an important Old World center of diversification for the B. tabaci complex, together with sub-Saharan Africa. 相似文献
879.
本书的作者在大学讲授应用数学有30多年,在教学中发现,已有的一些教材并不完全适用,于是作者根据实际情况,逐步用自已的方式教学,最后编写了本书。虽然书中的内容并不是全新的,但表述的方式要比已有教材好,使大学生容易阅读,因此, 相似文献
880.
An experimental pectate lyase enzyme was used toscour knitted cotton fabric and the emphasis was on pectinremoval. Using an enzyme dosage of 0.2 g/L at temperature55℃ and pH 6.35 for 30 rain, good scouring properties wereobtained. When appropriate concentrations of 1 - HydroxyEthylidene- 1, 1 - Diphosphonic Acid(HEDP) and CaCl2were added, the percentage pectin removal improvedsignificantly. 相似文献