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41.
Both total irradiation and diffuse irradiation are necessary to building energy consumption analysis. At the most cases in China,only total irradiation is available. So some method is needed to estimate diffuse irradiation. Relationship between daily diffuse irradiation and daily total irradiation is analyzed, based on data form Beijing and Chengdu.Polynomial models for Beijing and Chengdu are established to estimate K d form K t . Validation tests show good performance of the models. Monthly means of predicted daily diffuse irradiation is not significantly different from that of the original daily diffuse irradiation. Also,the auto_correlation function of the predicted diffuse fraction, K d is coincident with that of the original K d . Beijing model can accurately predict the data of Chengdu,which is significantly different from Beijing as to the climate,so it is recommended as the general model. 相似文献
42.
This paper investigates the coordinated operation of the progress planning with the resource planning when carrying out engineering projects and puts forward a method of "RSM" under the resource limit conditions. Then, the "RSM" was improved to avoid complicated calculation. This method not only reduces the calculating work by hand but saves computer's memory as well, making the time-resource optimization work more quick and convenient. 相似文献
43.
The Lexicographic method has subjective and empirical character,so a weighting coefficient is introduced by considering the importance and proportion of each individual object,the preferable result of every individual object can be confirmed by comparing the degree of similarity between the perfect one and the ecumenic one and the Fuzzy optimization will be perfect.The effectiveness of these methods is illustrated by a fuzzy optimal design of the three-bar truss. 相似文献
44.
Image compression is very important in picture archiving and communication system(PACS). The author studied the statistical distribution of image wavelet subimage coefficients and concluded that the distribution of wavelet subimage coefficients is similar to that of Laplasian distribution. On the other hand, in image reconstruction, the coefficient with different amplitude owns different weight, and different accuracy can be applied to different coefficients according to their different weight. Then, the author has designed a image quantization encoding scheme for PACS. In this scheme, they selected the sample-standard-deviation of coefficients in every subimage as the quantization threshold, and accurately encoded those coefficients with higher weight. Also, this algorithm utilized the visual character of human. The test has proved that the main advantages of this method are the simplicity in computing and predictable encoded coefficients, and a high compression efficiency can obtain too. 相似文献
45.
Bill of material of product is data about product structure, and plays an important role in product information management. The paper analyzed characteristics of product BOM, and put forward a product BOM management method based on single layer BOM, witch can well meet requirements of product BOM. 相似文献
46.
The method and principle of the parameter design for the power train of EV is explored and discussed,then the parametersof EV. based on SC7101 are reasonably selected.The method of calculating the SOC of Lead_acid battery is provided and the relation among the electromotive force,the interior resistance, the polarized resistance and the SOC are analyzed. The capacity is compensated according to the relation between the capacity and the temperature, which is the basis on which the energy management system is designed and improved. The dynamic model which reflects the dynamic characteristics of the power train is established,then the dynamic performance of the EV based on SC7101 is simulated, and the factors that affect the continuous mileage of EV are analyzed,the measures to increase the continuous mileage are provided.The result shows that the analysis of the electric characteristics of battery and the dynamic model are correct,and the dynamic performance perfectly meets the need of the design target. 相似文献
47.
This paper provides a conception of brightness and puts stress upon application of brightness to science of illuminating engineering and actual illuminating engineering. 相似文献
48.
The 99% of all microorganisms in naturecannot be isolated by standard culture methods without conspicuous external characters to classify them morphologically. In addition, classification based on physiological or biochemical features are often fuzzy. Molecular techniques are used for uncultured microorganisms to explore the diversity of microbial communities and novel resources without the need of cultivation. DNA dynamics and cloning of PCR products obtained from environmental DNA is now routinely used to identify microbial populations in microbial ecology. For practical reasons the approach is not suited to study the complex dynamics of microbial communities in environment. Genetic fingerprinting techniques are better tools, which give complement for the traditional microbiological methods. The methods are rapid and relatively easy to perform, and they allow the simultaneous analysis of multiple samples, which makes it possible to compare the genetic diversity of microbial communities from different habitats, or to study the behaviour of individual communities over time. 相似文献
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