A Task Allocation Algorithm with Weighted Average Velocity Based on Online Active Period

In some complex scientific calculation, the resources of the calculation are very large. To a certain extent, the improvement of the computer level has met the needs of many computing, but a lot of more complex calculation cannot still be effectively resolved. Volunteer computing is a computational method that divides the complexity of computing tasks into simple subtasks, and collects the results of volunteer computing resources to solve the subtasks. In this calculation process, the task assignment module is an extremely important part of the whole computing platform. Many of the existing task allocation algorithms (TAA) are used to group by the similar conditions of the volunteer computer. TAA used in this work grouped by the computers with similar online active period, and the computation efficiency is improved by using the weighted average velocity as a parameter. The experimental results showed that TAA with the weighted average velocity based on online active period can effectively improve the performance of the volunteer computing platform. Keywords: Volunteer computing; Task allocation algorithm; Weighted average velocity; Online active perio

A Dynamic Task Allocation Algorithm Based on Weighted Velocity

Volunteer computing is a way of supporting people around the world who provide free computer resources, to participate in scientific calculation or data analysis on the Internet. This provides an effective solution to solve the problems of large scale of basic scientific computing and more computing resources requirements. Task allocation is a very important part of volunteer computing. An effective algorithm can significantly improve computational efficiency. At present, most of the existing tasks are divided in term of the computer hardware conditions or the initial state of the computer in the volunteer computing. It seems that this have no obvious impact to calculating efficiency in a short time, but this task will be less flexible when idle resources of the volunteer computing becomes less or more. To make full use of idle computer resources, a dynamic task allocation algorithm (TAA) based on weighted velocity was proposed in this work. The research results showed that the weighted velocity as a parameter can be used to test the computing performance of a computer, dynamically manage task allocation as well. Keywords: volunteer computing, task allocation, weighted average velocit

Estimating the crop leaf area index using hyperspectral remote sensing

AbstractThe leaf area index (LAI) is an important vegetation parameter, which is used widely in many applications. Remote sensing techniques are known to be effective but inexpensive methods for estimating the LAI of crop canopies. During the last two decades, hyperspectral remote sensing has been employed increasingly for crop LAI estimation, which requires unique technical procedures compared with conventional multispectral data, such as denoising and dimension reduction. Thus, we provide a comprehensive and intensive overview of crop LAI estimation based on hyperspectral remote sensing techniques. First, we compare hyperspectral data and multispectral data by highlighting their potential and limitations in LAI estimation. Second, we categorize the approaches used for crop LAI estimation based on hyperspectral data into three types: approaches based on statistical models, physical models (i.e., canopy reflectance models), and hybrid inversions. We summarize and evaluate the theoretical basis and different methods employed by these approaches (e.g., the characteristic parameters of LAI, regression methods for constructing statistical predictive models, commonly applied physical models, and inversion strategies for physical models). Thus, numerous models and inversion strategies are organized in a clear conceptual framework. Moreover, we highlight the technical difficulties that may hinder crop LAI estimation, such as the “curse of dimensionality” and the ill-posed problem. Finally, we discuss the prospects for future research based on the previous studies described in this review

catena-Poly[[[aqua­[3-(3-hy­droxy­phen­yl)prop-2-enoato]samarium(III)]-bis­[μ2-3-(3-hy­droxy­phen­yl)prop-2-enoato]] monohydrate]

The title SmIII compound, {[Sm(C9H7O3)3(H2O)]·H2O}n, was obtained under hydrothermal conditions. Its structure is isotypic with the analogous Eu complex. The latter was reported incorrectly in space group P1 by Yan et al. [J. Mol. Struct. (2008), 891, 298–304]. This was corrected by Marsh [Acta Cryst. B65, 782–783] to P-1. The SmIII ion is nine-coordinated by O atoms from one coordinating water molecule and the remaining ones from the 3-(3-hy­droxy­phen­yl)prop-2-enoatate anions (one bidentate, two bidentate and bridging, two monodentate bridging), leading to a distorted tricapped trigonal–prismatic coordination polyhedron surrounded by solvent water mol­ecules. In the crystal, extensive intermolecular O—H⋯O hydrogen-bonding inter­actions and π–π inter­actions [centroid–centroid separation = 3.9393 (1) Å] lead to the formation of a three-dimensional supra­molecular network

Clinical assessment of 252Californium neutron intracavitary brachytherapy using a two-channel Y applicator combined with external beam radiotherapy for endometrial cancer

OBJECTIVE: The aim of this study was to determine the efficacy of 252Californium neutron intracavitary brachytherapy using a two-channel Y applicator combined with external beam radiotherapy for the treatment of endometrial cancer. METHODS: Thirty-one patients with stage I-III endometrial cancer were recruited for this study. The stage I patients received only 252Californium neutron intracavitary brachytherapy with a two-channel applicator. The stage II and III patients received both 252Californium neutron intracavitary brachytherapy using a two-channel applicator and parallel-opposed whole pelvic radiotherapy. RESULTS: The five-year local control rate was 80.6% (25/31), the overall survival rate was 51.6% (16/31), and the disease-free survival rate was 54.8% (17/31). The incidence of serious late complications was 12.9% (4/31). CONCLUSIONS: 252Californium neutron intracavitary brachytherapy using a two-channel applicator combined with external beam radiotherapy was effective for treating endometrial cancer and the incidence of serious late complications related to this combination was within an acceptable range

Numerical simulation on the aerodynamic force of the iced conductor for different angles of attack

According to the galloping mechanism of iced conductors, the aerodynamic simulations were performed based on actual wind tunnel tests. Aeroelastic models of single and bundled conductors with a typical ice-coating section forms (crescent section) were set up. The simulation results were in good agreements with wind tunnel tests, and it showed that numerical simulation method can be used instead of wind tunnel tests. The wind attack angles have seriously affected the aerodynamic force of the iced conductor. The wake of vortex shedding for the iced single conductor was analyzed. As for the iced bundled conductors, sub-conductors at the downstream were seriously influenced by the ones at the upstream locations and the aerodynamic force of the sub-conductors at the downstream was lower than of those at the upstream. The negative slope of Nigol coefficient to the bundled conductors was larger than that of the single wire, but the absolute value of the amplitude was less than that of the single conductor, and the bundled conductors were more likely to gallop than the single ones. The Den. Hartog and O.Nigol mechanism were used to predict galloping of iced conductors, which can be convenient for analyzing vibration of iced conductors