14,687 research outputs found
On-line extensible bin packing with unequal bin sizes
No full textAnalysis of AlgorithmsInternational audienceIn the extensible bin packing problem we are asked to pack a set of items into a given number of bins, each with an original size. However, the original bin sizes can be extended if necessary. The goal is to minimize the total size of the bins. We consider the problem with unequal (original) bin sizes and give the complete analysis on a list scheduling algorithm (LS). Namely we present tight bounds of LS for every collection of original bin sizes and every number of bins. We further show better on-line algorithms for the two-bin case and the three-bin case. Interestingly, it is proved that the on-line algorithms have better competitive ratios for unequal bins than for equal bins. Some variants of the problem are also discussed
su-Based Shaft Friction Design Method and Evaluation for Pipe Pile
No full textThe shaft friction in clay is essential to bearing capacity of pipe piles. Reasonable selection of design methods and parameters is very important for offshore piles. This paper focuses on the current popular vertical load design methods based on undrained strength for pipe piles, especially for offshore piles. Based on the database, the accuracy and reliability of various pile design methods based on undrained strength su in clay were reviewed. The small-scale model tests were conducted to evaluate su-based methods. For the shortcomings of small-diameter piles in the database, a field test of full-scale offshore pile was carried out and analysed. By comparing the calculated and the measured capacity for each method, the reliability of various design methods is evaluated for large-diameter piles. For the design methods based on undrained strength, it demonstrates the importance and reliability of the determination of undrained strength parameters. In view of the vertical loading conditions of offshore large-diameter steel pipe piles, reasonable suggestions for design methods and parameters determination are given
nayl al'umnit ealaa muqadimat aleazia Sheikh Muhammad Ali bin Hussein bin Ibrahim al-Makki al-Maliki 1367h- Study and investigation
No full textThis research consist of a study and investigation of the manuscript: (nayl al\u27umnit ealaa muqadimat aleazia), by Sheikh Muhammad Ali bin Hussein al-Maliki al-Maliki (1367h), in Maliki Fiqh, the researcher saw the importance of publication of the manuscript, because of that he wrote this research, that consists the introduction of the Author and an introduction of the manuscript. overall, the research enhanced on many progressive outcomes that are valuable in the field of this research.
 
Bin-to-bin spectrum reconstruction method for analyzing γ-rays passing through a certain thickness of aluminum
No full textAgri Ibrahim Cecen University;IC Foudation2nd International Conference on Advances in Natural and Applied Sciences, ICANAS 2017 -- 18 April 2017 through 21 April 2017 -- 127507Energy distribution of Y-rays emitted from standard sources, passing through various thicknesses of Al medium, were obtained by using 5.08cm x 5.08cm NaI(Tl) detector. The full energy peak and the total efficiency, photopeak/total (P/T) ratios and energy resolution of NaI(Tl) detector were measured using standard Y-ray sources. Detector response functions (DRFs) were obtained in every energy value of Y-ray rays by means of P/T ratios and energy resolutions. Y-rays incoming to the slice-shape geometry medium, can take all the energy values between 0 and the maximum energy. The energy range is divided into n lower energy region. DRFs are obtained for the energy values correspond to the midpoint of each energy range. In this way, the response matrix is developed. A bin to bin unfolding method is applied to the Y-ray spectra and the results are compared with the spectra obtained by the Monte Carlo method. © 2017 Author(s)
Cascading failure analysis considering interaction between power grids and communication networks
No full textThis paper aims to model interdependencies between power systems and dispatching data networks, and to analyze the intricate impacts on cascading failures. The functions of communication networks are embedded into dispatching data networks in China, thus we use dispatching data networks in the paper. The structures of dispatching data networks are generally categorized into two types: 1) double-star; and 2) mesh. The correlation of nodes in double-star networks and power systems is “degree to degree,” whereas “degree to betweenness” is the correlation for mesh networks. Furthermore, the interactive model between power grids and dispatching data networks is presented by a dynamic power flow model. Taking the IEEE 39-bus system and China's Guangdong 500-kV system as examples, in the case of random attacks on the interdependent system, simulation results show that the power grid coupled with double-star dispatching data networks has lower probability of catastrophic failures than with the mesh structure, because the double-star dispatching data network has outstanding capability of delivering information even though some communication nodes are out of order. In contrast, under intentional attacks, the decrement of the transmission performance of the double-star network is more serious than that in the mesh network. Therefore, the power system exhibits much higher vulnerability when coupled with the double-star network
The heterogeneous effects of socioeconomic determinants on PM2.5 concentrations using a two-step panel quantile regression
No full textThe haze pollution caused by high PM
2.5 concentrations has adverse health effects worldwide, especially in rapidly developing China. As meteorological conditions are uncontrollable, this study aims to investigate how anthropogenic factors affect the PM
2.5 concentration under high, medium and low emission levels. The distribution of socioeconomic variables is often non-normal, with important information hidden in the tail. By using balanced panel data of 273 Chinese cities from 2010 to 2016, two-step panel quantile regression is adopted to examine the cross-quantile heterogeneity of seven socioeconomic variables: economic growth, industrial structure, urbanization, foreign direct investment (FDI), population density, public transportation and energy consumption. The empirical results show that the relationships of PM
2.5 concentration with economic growth, urbanization, industrialization and FDI are heterogeneous. Compared with other variables, population density exerts the greatest positive effect on PM
2.5 pollution across all quantile cities. Moreover, the impact of GDP per capita on PM
2.5 concentration in the lower 25th quantile cities is stronger than those in the 25th-50th, 50th-75th and upper 75th quantile cities. The effects of FDI in the upper 75th and lower 25th quantile cities are higher than those in the 25th-50th and 50th-75th quantile cities, which supports the “pollution haven” hypothesis. The impact of industrial structure on PM
2.5 concentration in the upper 75th quantile cities is larger than those in the 0-25th, 25th-50th, and 50th-75th quantile cities. The heterogeneous effects of these socioeconomic determinants could assist policymakers in implementing differentiated policies that fit cities with different levels of air pollution.
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