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51.
Multidimensional Cube Packing 总被引:1,自引:0,他引:1
Yoshiharu Kohayakawa Flavio Keidi Miyazawa Prabhakar Raghavan Yoshiko Wakabayashi 《Algorithmica》2004,40(3):173-187
We consider the d-dimensional cube packing problem (d-CPP): given a list L of d-dimensional
cubes and (an unlimited quantity of) d-dimensional unit-capacity cubes, called bins, find a packing of L into
the minimum number of bins. We present two approximation algorithms for d-CPP, for fixed d. The first
algorithm has an asymptotic performance bound that can be made arbitrarily close to 2 – (1/2)d . The second
algorithm is an improvement of the first and has an asymptotic performance bound that can be made arbitrarily
close to 2 – (2/3)d . To our knowledge, these results improve the bounds known so far for d = 2 and d = 3, and
are the first results with bounds that are not exponential in the dimension. 相似文献
52.
Fractal symbolic analysis is a symbolic analysis technique for verifying the legality of program transformations. It is strictly more powerful than dependence analysis; for example, it can be used to verify the legality of blocking LU factorization with pivoting, a task for which dependence analysis is inadequate. In this paper, we show how fractal symbolic analysis can be used to convert between left- and right-looking versions of three kernels of central importance in computational science: triangular solve, Cholesky factorization, and LU factorization with pivoting. 相似文献
53.
A series of phase-pure Co- and Al-substituted lithium nickel oxide solid solutions of the composition LiNi0.7Al0.3−xCoxO2 with x=0.0, 0.1, 0.15, 0.2, and 0.3, has been synthesized by adopting urea-assisted combustion (UAC) route. The structure and the physico-electrochemical features of the doped materials have been evaluated through PXRD, FTIR, SEM, CV, and charge/discharge studies. The stabilization of Ni in the +3 state and the existence of enhanced 2D-layered structure without any cation mixing have been substantiated from XRD. The results of the XRD and FTIR studies have established the complete mixing of Al and Co with Ni, especially at the various levels and the combinations of the dopants attempted in the present study. The enhanced electrochemical performance of LiNi0.7Al0.3−xCoxO2 may be attributed to the “synergetic effect” resulting from the presence of both Al3+ and Co3+ dopants in the LiNiO2 matrix. From CV studies, it was understood that the addition of 10% Co is effective in suppressing the phase transformation during Li+ intercalation process that leads to better electrochemical properties. The effect and the extent of substitution of Ni with Al and Co on the structural and electrochemical performance of LiNi0.7Al0.3−xCoxO2 are discussed elaborately in this communication. 相似文献
54.
Numerical schemes and stability criteria are developed for solution of the one-dimensional fractional advection-dispersion equation (FRADE) derived by revising Fick’s first law. Employing 74 sets of dye test data measured on natural streams, it is found that the fractional order F of the partial differential operator acting on the dispersion term varies around the most frequently occurring value of F = 1.65 in the range of 1.4 to 2.0. Two series expansions are proposed for approximation of the limit definitions of fractional derivatives. On this ground, two three-term finite-difference schemes?“1.3 Backward Scheme” having the first-order accuracy and “F.3 Central Scheme” possessing the F-th order accuracy?are presented for fractional order derivatives. The F.3 scheme is found to perform better than does the 1.3 scheme in terms of error and stability analyses and is thus recommended for numerical solution of FRADE. The fractional dispersion model characterized by the FRADE and the F.3 scheme can accurately simulate the long-tailed dispersion processes in natural rivers. 相似文献
55.
An instrument to measure the respiration rate of whole fruits and vegetables was designed and developed using a pressure variation method. The Motorola MPX-10-DP pressure transducer was used to monitor pressure changes due to respiratory activity. The operating procedures and calculations required to determine respiration rate (RR) in terms of CO2 produced, RR-CO2, and O2 consumed, RR-O2, with the respirometer were simple. The values of RR-CO2 and RR-O2 obtained by the pressure variation method were compared to changes in CO2 and O2 concentrations as determined by gas chromatography. The results showed no significant difference (0.05 level) between the two methods. 相似文献
56.
Cao Dongyang Malakooti Sadeq Kulkarni Vijay N. Ren Yao Lu Hongbing 《Mechanics of Time-Dependent Materials》2021,25(3):353-363
Mechanics of Time-Dependent Materials - Debonding at the core–skin interphase region is one of the primary failure modes in core sandwich composites under shear loads. As a result, the... 相似文献
57.
Shweta Pandey Asiya Mahtab Vijay Kumar Farhan Jalees Ahmad Anita Kamra Verma 《Drug development and industrial pharmacy》2013,39(7):1181-1192
The aim of this investigation is the management of rheumatoid arthritis (RA) by developing methotrexate-loaded calcium phosphate nanoparticles (MTX-CAP-NP) and to evaluate pharmacokinetic and pharmacodynamic behavior in adjuvant induced arthritis model. The nanoparticles were synthesized by wet precipitation method and optimized by Box-Behnken experimental design. MTX-CAP-NPs were characterized by TEM, FTIR, DSC and XRD studies. The particle size, zeta potential and entrapment efficiency of the optimized nanoparticles were found to be 204.90?±?64?nm, ?11.58?±?4.80?mV, and 88.33?±?3.74%, respectively. TEM, FTIR, DSC and XRD studies revealed that the developed nanoparticles were nearly spherical in shape and the crystalline structure of CAP-NP was not changed after MTX loading. The pharmacokinetic studies revealed that MTX-CAP-NP enhanced bioavailability of MTX by 2.6-fold when compared to marketed formulation (FOLITRAX-10). Under pharmacodynamic evaluation, arthritic assessment, radiography and histopathology studies revealed that CAP has ability to regenerate cartilage and bone therefore, together with MTX, MTX-CAP-NPs have shown significant reduction in disease progression. The overall work demonstrated that the developed nanodelivery system was well tolerated and more effective than the marketed formulation. 相似文献
58.
On a stochastic sensor selection algorithm with applications in sensor scheduling and sensor coverage 总被引:1,自引:0,他引:1
Vijay Gupta Author Vitae Timothy H. Chung Author Vitae Author Vitae Richard M. Murray Author Vitae 《Automatica》2006,42(2):251-260
In this note we consider the following problem. Suppose a set of sensors is jointly trying to estimate a process. One sensor takes a measurement at every time step and the measurements are then exchanged among all the sensors. What is the sensor schedule that results in the minimum error covariance? We describe a stochastic sensor selection strategy that is easy to implement and is computationally tractable. The problem described above comes up in many domains out of which we discuss two. In the sensor selection problem, there are multiple sensors that cannot operate simultaneously (e.g., sonars in the same frequency band). Thus measurements need to be scheduled. In the sensor coverage problem, a geographical area needs to be covered by mobile sensors each with limited range. Thus from every position, the sensors obtain a different view-point of the area and the sensors need to optimize their trajectories. The algorithm is applied to these problems and illustrated through simple examples. 相似文献
59.
Srimanth?Gadde William?Acosta Jordan?Ringenberg Robert?GreenEmail author Vijay?Devabhaktuni 《International journal of parallel programming》2016,44(4):772-800
Processing large graph datasets represents an increasingly important area in computing research and applications. The size of many graph datasets has increased well beyond the processing capacity of a single computing node, thereby necessitating distributed approaches. As these datasets are processed over a distributed system of nodes, this leads to an inter-node communication cost problem that negatively affects system performance. Previously proposed algorithms implemented breadth-first search (BFS) for graph searching and focused on the execution, parallel performance and not the communication. In this paper a new methodology is proposed that combines BFS with random selection in order to partition large graph datasets and effectively minimize inter-node communication. The new method is discussed and applied to the single-source shortest path and PageRank algorithms using three graphs that are representative of real-world scenarios. Experimental results show that graph inter-node communication for canonical graphs representative of real-world data is improved up to 42 % in case of Powerlaw graph, up to 27 % in case of Random near K-regular graph (with low degree), and up to 7 % in case of Random near K-regular graph (with high degree). 相似文献
60.
Graph structure in the Web 总被引:11,自引:0,他引:11
Andrei Broder Ravi Kumar Farzin Maghoul Prabhakar Raghavan Sridhar Rajagopalan Raymie Stata Andrew Tomkins Janet Wiener 《Computer Networks》2000,33(1-6)
The study of the Web as a graph is not only fascinating in its own right, but also yields valuable insight into Web algorithms for crawling, searching and community discovery, and the sociological phenomena which characterize its evolution. We report on experiments on local and global properties of the Web graph using two AltaVista crawls each with over 200 million pages and 1.5 billion links. Our study indicates that the macroscopic structure of the Web is considerably more intricate than suggested by earlier experiments on a smaller scale. 相似文献