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61.
The goal of Grid computing is to integrate the usage of computer resources from cooperating partners in the form of Virtual Organizations (VO). One of its key functions is to match jobs to execution resources efficiently. For interoperability between VOs, this matching operation occurs in resource brokering middleware, commonly referred to as the meta-scheduler or meta-broker. In this paper, we present an approach to a meta-scheduler architecture, combining hierarchical and peer-to-peer models for flexibility and extensibility. Interoperability is further promoted through the introduction of a set of protocols, allowing meta-schedulers to maintain sessions and exchange job and resource state using Web Services. Our architecture also incorporates a resource model that enables an efficient resource matching across multiple Virtual Organizations, especially where the compute resources and state are dynamic. Experiments demonstrate these new functional features across three distributed organizations (BSC, FIU, and IBM), that internally use different job scheduling technologies, computing infrastructure and security mechanisms. Performance evaluations through actual system measurements and simulations provide the insights on the architecture’s effectiveness and scalability.  相似文献   
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We propose a bi-objective cell formation problem with demand of products expressed in a number of probabilistic scenarios. To deal with the uncertain demand of products, a framework of two-stage stochastic programming model is presented. The proposed model considers minimizing the sum of the miscellaneous costs (machine constant cost, expected machine variable cost, cell fixed-charge cost, and expected intercell movement cost) and expected total cell loading variation. Because of conflicting objectives, we develop a two-phase fuzzy linear programming approach for solving bi-objective cell formation problem. To show the effectiveness of the proposed approach, numerical examples are solved and the results are compared with the two existing approaches in the literature. The computational results show that the proposed fuzzy method achieves lower objective functions as well as higher satisfaction degrees.  相似文献   
64.
Multimedia Tools and Applications - Constant increasing of visual information necessitates most efficient image compression schemes for saving storage space or reducing required transmission...  相似文献   
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Employing Modular Robotic Systems (MRS) in different application domains confronts a large number of challenging problems in design, optimization, and planning, and so identifying characteristics of such problems is an important step toward finding proper solution approaches for them. In this paper, we address this issue and provide a comprehensive study on MRS through a structured survey about MRS characteristics and their applications. A novel framework called MITE is proposed to characterize both the properties and applications of MRS from four perspectives of Module, Information, Task, and Environment, based on more than 120 domain-specific features, supplemented by a mapping scheme for describing the interrelations of the four basic aspects of the Task component, namely, Application (for describing high-level tasks such as navigation and rescue), Behavior (for referring to constitutive behaviors like locomotion and manipulation which bring about Applications), Goal (for characterizing the way Behaviors are accomplished), and Operation (for designating activities specific to modular robots, such as self-reconfiguration and gait control). Also, by providing a methodical review on modular robotics, the paper deals with some analyses on recent trends, research gaps and challenges, as well as open problems in the field of MRS.  相似文献   
67.
Nylon 6 nanofibers incorporated with molecularly imprinted polymers (MIPs) were successfully fabricated by electrospinning with fiber diameters in the range 80–145 nm. Then, they were used as a new material for the extraction of selected bisphenol A (BPA) in water samples. Field emission scanning electron microscopy images revealed that the nanofibers had a smooth morphology with a good incorporation of MIPs. The Fourier transform infrared and energy-dispersive X-ray spectroscopy results also confirmed the formation of the MIPs in the nanofibers. Furthermore, Raman spectroscopy showed that the crystalline structure of the pristine nylon 6 nanofiber was a kind of α form, and the incorporation of MIPs led to a γ-form structure in the nanofibers; this proved the interactions between nylon 6 and the MIPs. Adsorption studies also confirmed that the adsorption efficiency of BPA onto the molecularly imprinted polymer nanofibers (MIP-NFs; 83.5%) was much greater than that onto nonimprinted polymer nanofibers (NIP-NFs; 36.8%). Also, the imprinting factor was 3.4; this strongly implied the successful formation of molecularly imprinted cavities on the MIP-NFs with a strong affinity to BPA. The maximum adsorption capacity of the MIP-NFs was 103.8 mg/g. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47112.  相似文献   
68.
Hydrogen storage technology is one of the most challenging issues due to the increasing demand for fossil fuel replacement and the reduction of greenhouse gas emissions. In the current paper, the main aim is one-step and eco-friendly preparation of DyFeO3-ZnO nanocomposites using Barberry fruit extract as natural precursor (with the role of both fuel and capping agent) to compare with various conventional carboxylic acids. To further examine, the effect of different parameters like calcination temperature and the type of the chelating agent was scrutinized to acquire optimum shape, structure, morphology and size of the obtained products. This is the first effort on the investigation of the hydrogen storage capacity of DyFeO3-ZnO nanocomposites in terms of role of morphology. The electrochemical hydrogen storage capacity of obtained DyFeO3-ZnO nanocomposites was studied mediated by chronopotentiometry charge-discharge methods in KOH medium. The synthesis of nanocomposites in the presence of chemical or natural capping agent (carboxylic acids or Barberry fruit extract) led to different morphologies which affects to the electrochemical performance. As a result, the electrode which is provided by plate-like DyFeO3-ZnO nanocomposites performed 600.11 mAh/g discharge capacity compared with other samples. Based on the obtained results, DyFeO3-ZnO nanocomposites can be promising compounds to improve the electrochemical performance of hydrogen storage.  相似文献   
69.
Polyvinylpolypyrrolidone-supported chlorosulfonic acid has been successfully applied to perform one-pot reaction of arylaldehydes, urea, ethylacetoacetate, or cyclic 1,3-diketo compounds under solvent-free condition at 70°C to provide a series of dihydropyrimidinones and octahydroquinazolin-2,5-diones in good to excellent yields. The method offers several advantages such as high yield, short reaction time, simple workup, easy preparation, and reusability of the catalyst. The [PVPP-SO3H]+Cl? catalyst was characterized via Fourier transform infrared spectroscopy (FT-IR) and thermal gravimetric analysis (TGA). Moreover, the catalyst could be recycled several times without significant loss of its catalytic activity. Clean methodologies, easy work-up procedure, high yield, and simple preparation of the catalyst are some advantages of this article.  相似文献   
70.
Multimedia Tools and Applications - A scene-level two-pass video rate controller for high efficiency video coding (HEVC) standard is proposed in this paper. The proposed rate controller is suitable...  相似文献   
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