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This work concerns the optimal regulation of single-input–single-output nonminimum-phase nonlinear processes. The problem of calculation of an ISE-optimal, statically equivalent, minimum-phase output for nonminimum-phase compensation is formulated using Hamilton–Jacobi theory and the normal form representation of the nonlinear system. A Newton–Kantorovich iteration is developed for the solution of the pertinent Hamilton–Jacobi equations, which involves solving a Zubov equation at each step of the iteration. The method is applied to the problem of controlling a nonisothermal CSTR with Van de Vusse kinetics, which exhibits nonminimum-phase behaviour. 相似文献
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Flow Routing and its Performance Analysis in Optical IP Networks 总被引:1,自引:0,他引:1
Optical packet-switching networks deploying buffering, wavelength conversion and multi-path routing have been extensively studied in recent years to provide high capacity transport for Internet traffic. However due to packet-based routing and switching, such a network could result in significant disorder and delay variation of packets when they are received by end users, thus increasing the burstiness of the Internet traffic and causing higher-layer protocol to malfunction. This paper addresses a novel routing and switching method for optical IP networks — flow routing, and its facilitating protocol. Flow routing deals with packet-flows to reduce flow corruption due to packet out-of-order, delay variation and packet loss, without using complicate control mechanism. Detailed performance analysis is given for output-buffered optical routers adopting flow routing. Two flow-oriented discarding techniques, i.e., flow discard (FD) and early flow discard (EFD), are discussed. Compared with optical packet-switching routers, a remarkable improvement of good-throughput is obtained in the optical flow-routers, especially under high congestion periods. We conclude that EFD behaves as a robust technique, which is more tolerant than FD to the change of traffic and transmission system factors. 相似文献
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G2MPLS is a Network Control Plane (NCP) architecture that implements the concept of Grid Network Services (GNS) required for implementing photonic Grids. It provides part of the functionalities related to the selection, co allocation and maintenance of both Grid and network resources through a set of seamless procedures at the user to network and inter domain boundaries. G2MPLS main features and procedures are presented in this document, as well as the considerations to deploy it and facilitate its dissemination. 相似文献
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Kostas Kounetas Athanasios Anastasiou Panagiotis Mitropoulos Ioannis Mitropoulos 《International Transactions in Operational Research》2011,18(5):545-559
The allocation funds mechanisms for universities and their departments seem to be a complex procedure for state authorities. Consequently, the question of how efficient universities and their departments are has been imposed by governments and policymakers. In this paper, we assess research performance of academic departments within a single Greek university. A Data Envelopment Analysis (DEA) application with six model variants was used to estimate technical efficiencies relative to best practice performance. Furthermore, our input–output criteria are determined and used to measure the departments' academic performance. To deliver reasonable results a Tobit model is considered in a second stage to examine the degree to which “environmental effects” impact on departmental efficiencies. We find that “environmental effects” such as departmental infrastructure, age and schools' personnel have an important role. 相似文献
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The study explores how online health communities produce social value by uniting individuals under a common purpose, to advance healthcare in post‐conflict states. We selected MedicineAfrica – a digital platform known for creating social value by providing medical education in regions with under‐resourced healthcare systems – and drew on multiple data collection methods. We found that it is through a unique form of digital health activism that social value is created in this context. Drawing on a sociological understanding of digital health activism, we make the following contributions: First, we identify three types of non‐economic, social value: cognitive, professional and epistemic. Second, we indicate that social value creation is enabled by three emergent forms of digital health activism (ie, philanthropic, moral and reciprocal activity). Third, we elicit three enabling mechanisms explaining how these forms of activism are technically and socially afforded through the platform's connective capacity and emerging collective practices in tandem with its members' growing commitment. Our article contributes to the growing IS literature on digital activism by offering a framework that elucidates how digital health activism relates to social value creation. The article provides practical implications as to how platforms can enable sustainable online (health) communities. 相似文献
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Maria Vasilopoulou George Papadimitropoulos Leonidas C. Palilis Dimitra G. Georgiadou Panagiotis Argitis Stella Kennou Ioannis Kostis Nikolaos Vourdas Nikolaos A. Stathopoulos Dimitris Davazoglou 《Organic Electronics》2012,13(5):796-806
In this work we demonstrate the unique hole injection and transport properties of a substoichiometric tungsten oxide with precise stoichiometry, in particular WO2.5, obtained after the controlled hydrogen reduction during growth of tungsten oxide, using a simple hot-wire vapor deposition technique. We present clear evidence that tungsten suboxide exhibits metallic character and that an almost zero hole injection barrier exists at the anode/polymer interface due to the formation/occupation of electronic gap states near the Fermi level after oxide’s reduction. These states greatly facilitate hole injection and charge generation/electron extraction enabling the demonstration of extremely efficient hole only devices. WO2.5 films exhibit metallic-like conductivity and, thus, can also enhance charge transport at both anode and cathode interfaces. Electroluminescent devices using WO2.5 as both, hole and electron injection layer, and poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1′,3}-thiadiazole)] (F8BT) as the emissive layer exhibited high efficiencies up to 7 cd/A and 4.5 lm/W, while, stability studies revealed that these devices were extremely stable, since they were operating without encapsulation in air for more than 700 h. 相似文献
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