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排序方式: 共有265条查询结果,搜索用时 31 毫秒
21.
Mahmut Sonmez 《International Transactions in Operational Research》2007,14(5):411-429
This paper describes the application of an evidential reasoning (ER)‐based decision making process to multiple‐criteria decision making (MCDM) problems having both quantitative and qualitative criteria. The ER approach is based on the decision theory and the theory of evidence and it uses the concept of ‘degree of belief’ to assess decision alternatives on each attribute. When faced with MCDM problems, evaluation and selection or ranking of alternatives appear to be both challenging and vital to arrive at a rational and robust decision. In the presence of both qualitative and quantitative evaluations in an MCDM problem, it is necessary, when using the ER‐based decision making process, to transform or convert quantitative data into a belief structure using a number of grades so that the converted belief structure and the original quantitative data are equivalent in values or utilities. This paper suggests three scenarios for data transformation and examines how the ranking of decision alternatives is changed when different scenarios of data transformation are used. Ranking of UK universities using the ER approach is illustrated as an example. 相似文献
22.
Faster product development and increased competition in retail industries is resulting in shorter and shorter product life-cycles. This phenomenon is making it more difficult for a firm to accurately estimate random demand of such products and to plan their one-time order quantity accordingly. In this paper, we develop a model to assess the multiple effects of coordinated - i.e., joint - stocking and prior-sale discount decisions: (i) on the reduction of demand uncertainty; (ii) on maximization of the expected profit; and (iii) on the probability of achieving or exceeding it. We develop the joint optimal decisions that maximize the expected profit and discuss a procedure for computing the probability that the realized value of the (random) profit will exceed its maximum expected value. We present qualitative results on the varying effects of joint decisions on increasing the expected profit and the probability of achieving or exceeding it. We also describe a detailed numerical study examining the effects of varying parameter values on the percentage increase in expected profit with joint decision making. The paper concludes with extensions of the model that can deal with more general situations. 相似文献
23.
The photophysical and photochemical properties of the tetra- and octa-12-crown-4-substituted zinc (II) phthalocyanines are reported for the first time in the scope of this work. The new compounds have been characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy, electronic spectroscopy and mass spectra. General trends are described for photodegradation, singlet oxygen and fluorescence quantum yields, and fluorescence lifetimes of these compounds in dimethylsulphoxide (DMSO). Photophysical and photochemical properties of phthalocyanine complexes are very useful for photodynamic therapy (PDT) applications. The effects of the substituents on the photophysical and photochemical parameters of the zinc (II) phthalocyanines (5, 6 and 7) are also reported. The singlet oxygen quantum yields (ΦΔ) ranged from 0.48 to 0.78 are indicating the potential of the complexes as photosensitizers in applications of PDT. The fluorescences of the substituted ZnPc complexes are effectively quenched by benzoquinone (BQ). 相似文献
24.
Wei-lun Hung Yuan Xie Narayanan Vijaykrishnan Mahmut Kandemir Mary Jane Irwin 《Journal of Signal Processing Systems》2010,58(2):145-160
Power consumption is a top priority in high performance circuit design today. Many low power techniques have been proposed
to tackle the ever serious, highly pressing power consumption problem, which is composed of both dynamic and static power
in the nanometer era. The static power consumption nowadays receives even more attention than that of dynamic power consumption
when technology scales below 100 nm. In order to mitigate the aggressive power consumption, various existing low power techniques
are often used; however, they are often applied independently or combined with two or at most three different techniques together,
and that is not sufficient to address the escalating power issue. In this paper, we present a power optimization framework
for the minimization of total power consumption in combinational logic through multiple V
dd
assignment, multiple V
th
assignment, device sizing, and stack forcing, while maintaining performance requirements. These four power reduction techniques
are properly encoded into the genetic algorithm and evaluated simultaneously. The overhead imposed by the insertion of level
converters is also taken into account. The effectiveness of each power reduction mechanism is verified, as are the combinations
of different approaches. Experimental results are presented for a number of 65 nm benchmark circuits that span typical circuit
topologies, including inverter chains, SRAM decoders, multiplier, and a 32 bit carry adder. Our experiments show that the
combination of four low power techniques is the effective way to achieve low power budget. The framework is general and can
be easily extended to include other design-time low power techniques, such as multiple gate length or multiple gate oxide
thickness. 相似文献
25.
26.
Ali Erdoğmuş Mahmut Durmuş Ahmet Lütfi Uğur Oğuzhan Avciata Ulvi Avciata Tebello Nyokong 《Synthetic Metals》2010,160(17-18):1868-1876
The synthesis, photophysical and photochemical properties of soluble 3,4-(methylendioxy)-phenoxy substituted oxo-titanium(IV) phthalocyanines (4–6) are reported for the first time. The new compounds have been characterized by elemental analysis, FT-IR, 1H NMR spectroscopy, electronic spectroscopy and mass spectra. General trends are described for fluorescence lifetimes and fluorescence, photodegradation and singlet oxygen quantum yields, of these compounds in dimethylsulfoxide (DMSO) and toluene. The effects of the position of the substituents and solvent effect on the photophysical and photochemical parameters of the oxo-titanium(IV) phthalocyanines (4–6) are also reported. The fluorescence of the substituted oxo-titanium(IV) phthalocyanine complexes (4–6) is effectively quenched by 1,4-benzoquinone (BQ) in both DMSO and toluene. 相似文献
27.
Ceylan Zafer Mahmut Kus Gulsah Turkmen Haluk Dincalp Serafettin Demic Baha Kuban Yildirim Teoman Siddik Icli 《Solar Energy Materials & Solar Cells》2007,91(5):427-431
We have studied the influence of the spacer alkyl chain length of perylenemonoimide (PMI) dyes on the device performance in dye-sensitized solar cells (DSSCs). We observed that the dyes with longer and brunched alkyl chains exhibit higher efficiencies in DSSCs. In line with these statements we now report the highest efficiency obtained under standard conditions for a perylene imide derivative with PMI-DA1 that performs 300 mV open circuit voltage, 9.79 mA/cm2 short-circuit current and 1.61% overall conversion efficiency. 相似文献
28.
Experimental and theoretical analysis of particle distribution in particulate metal matrix composites 总被引:2,自引:0,他引:2
Particle distribution in particulate metal matrix composites was investigated experimentally and theoretically. SiC reinforced Pb 20%Sn alloy mechanically was stirred and cast into a cylindrical mold by an inert gas pressure. Particle distribution in the cast is determined at several locations by sectioning and microscopic investigation techniques. The particle fraction is found to decrease along the axis of the mold. The regions close to the boundary wall are determined as the possible clustering areas. A mathematical model is developed to characterize flow of mixture of molten metal alloy and ceramic particles. The distribution of particles is estimated from the trajectories of representative particles with the Lagrangian point of view. The numerical results are reasonably suited with experimental data. 相似文献
29.