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Distribution Scheme (distribution + scheme)
Selected AbstractsArchitecture for dynamic and fair distribution of bandwidthINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 5 2006Vasil Hnatyshin The problem of fair distribution of available bandwidth among traffic flows or aggregates remains an essential issue in computer networks. This paper introduces a novel approach, called the Exact Bandwidth Distribution Scheme (X-BDS), for dynamic and fair distribution of available bandwidth among individual flows. In this approach, the edge routers keep per-flow information, while the core routers maintain the aggregate flow requirements. The X-BDS approach employs a distributed message exchange protocol for providing network feedback and for distributing aggregate flow requirements among the nodes in the network. Based on the obtained feedback, the edge routers employ the X-BDS resource management unit to dynamically distribute available bandwidth among individual flows. The X-BDS admission control and resource management units are responsible for fair resource allocation that supports minimum bandwidth guarantees of individual flows. This paper evaluates the Bandwidth Distribution Scheme through simulation and shows that the X-BDS is capable of supporting per-flow bandwidth guarantees in a dynamically changing network environment. Copyright © 2006 John Wiley & Sons, Ltd. [source] A visual incompressible magneto-hydrodynamics solver with radiation, mass, and heat transferINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 10 2009Necdet AslanArticle first published online: 8 JAN 200 Abstract A visual two-dimensional (2D) nonlinear magneto-hydrodynamics (MHD) code that is able to solve steady state or transient charged or neutral convection problems under the radiation, mass, and heat transfer effects is presented. The flows considered are incompressible and the divergence conditions on the velocity and magnetic fields are handled by similar relaxation schemes in the form of pseudo-iterations between the real time levels. The numerical method utilizes a matrix distribution scheme that runs on structured or unstructured triangular meshes. The time-dependent algorithm developed here utilizes a semi-implicit dual time stepping technique with multistage Runge-Kutta (RK) algorithm. It is possible for the user to choose different normalizations (natural, forced, Boussinesq, Prandtl, double-diffusive and radiation convection) automatically. The code is visual and runs interactively with the user. The graphics algorithms work multithreaded and allow the user to follow certain flow features (color graphs, vector graphs, one-dimensional profiles) during runs, see (Comput. Fluids 2007; 36:961,973) for details. With the code presented here nonlinear steady or time-dependent evolution of heated and stratified neutral and charged liquids, convection of mixture of neutral and charged gases, double-diffusive and salinity natural convection flows with internal heat generation/absorption and radiative heat transfer flows can be investigated. In addition, the numerical method (combining concentration, radiation, heat transfer, and MHD effects) takes the advantage of local time stepping and employs simplified residual jacobian matrix to increase pseudo-convergence rate. This code is currently being improved to simulate three-dimensional problems with parallel processing. Copyright © 2009 John Wiley & Sons, Ltd. [source] Numerical solutions of liquid metal flows by incompressible magneto-hydrodynamics with heat transferINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 11 2009Kenan, entürk Abstract A two-dimensional incompressible magneto-hydrodynamic code is presented in order to solve the steady state or transient magnetized or neutral convection problems with the effect of heat transfer. The code utilizes a numerical matrix distribution scheme that runs on structured or unstructured triangular meshes and employs a dual time-stepping technique with multi-stage Runge,Kutta algorithm. The code can be used to simulate the natural convection with internal heat generation and absorption and nonlinear time-dependent evolution of heated and magnetized liquid metals exposed to external fields. Copyright © 2008 John Wiley & Sons, Ltd. [source] Multi-objective optimization of the coal combustion performance with artificial neural networks and genetic algorithmsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 6 2005Hao Zhou Abstract The present work introduces an approach to predict the nitrogen oxides (NOx) emissions and carbon burnout characteristics of a large capacity pulverized coal-fired boiler with an artificial neural network (ANN). The NOx emissions and carbon burnout characteristics are investigated by parametric field experiments. The effects of over-fire-air (OFA) flow rates, coal properties, boiler load, air distribution scheme and nozzle tilt are studied. An ANN is used to model the NOx emissions characteristics and the carbon burnout characteristics. A genetic algorithm (GA) is employed to perform a multi-objective search to determine the optimum solution of the ANN model, finding the optimal setpoints, which can suggest operators' correct actions to decrease NOx emissions and the carbon content in the flyash simultaneously, namely, get a good boiler combustion performance with high boiler efficiency while keeping the NOx emission concentration meet the requirement. Copyright © 2005 John Wiley & Sons, Ltd. [source] A heterogeneous-network aided public-key management scheme for mobile ad hoc networksINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 1 2007Yuh-Min Tseng A mobile ad hoc network does not require fixed infrastructure to construct connections among nodes. Due to the particular characteristics of mobile ad hoc networks, most existing secure protocols in wired networks do not meet the security requirements for mobile ad hoc networks. Most secure protocols in mobile ad hoc networks, such as secure routing, key agreement and secure group communication protocols, assume that all nodes must have pre-shared a secret, or pre-obtained public-key certificates before joining the network. However, this assumption has a practical weakness for some emergency applications, because some nodes without pre-obtained certificates will be unable to join the network. In this paper, a heterogeneous-network aided public-key management scheme for mobile ad hoc networks is proposed to remedy this weakness. Several heterogeneous networks (such as satellite, unmanned aerial vehicle, or cellular networks) provide wider service areas and ubiquitous connectivity. We adopt these wide-covered heterogeneous networks to design a secure certificate distribution scheme that allows a mobile node without a pre-obtained certificate to instantly get a certificate using the communication channel constructed by these wide-covered heterogeneous networks. Therefore, this scheme enhances the security infrastructure of public key management for mobile ad hoc networks. Copyright © 2006 John Wiley & Sons, Ltd. [source] Unstimulated whole saliva flow rate in relation to sicca symptoms in HungaryORAL DISEASES, Issue 5 2008K Márton Objective:, To assess the prevalence of xerostomia and the related oral and extraoral dryness symptoms in Hungary, to evaluate the association of those symptoms with the unstimulated whole saliva (UWS) flow rate, and to find correlation between the level of UWS flow rate and the oral health status of the questioned patients. Subjects And Methods:, A total of 600 patients between the age of 18 and 92 years, 265 male, 335 female, were selected in accordance with the current regional age and residence distribution scheme of the Hungarian Statistical Office. A questionnaire was designed to determine the subjective presence or absence of the sicca symptoms. UWS flow rate and the dental and periodontal status were determined. Results:, The percentages of subjective symptoms in the questioned subjects were oral dryness, 34%; reduced salivation, 11%; mucous saliva, 15%; dysphagia, 13%; glossopyrosis, 7%; dysphonia, 31%; dysgeusia, 9%; nasal dryness, 32%; ocular dryness, 21%; itching, 40% and xeroderma, 60%. Vaginal dryness was 14%, vaginal itching was 16% in the interviewed women. The grade of xerostomia, dysphagia, tiredness, and additionally the gingival bleeding index showed a negative correlation with the UWS flow rate. After all decayed, missing and filled teeth (DMF-T) mean values, gingival bleeding index and plaque index were significantly higher in hyposalivators, compared with those who had normal flow rates Conclusion:, This cross sectional study, representative of the Hungarian population, clearly shows that one-third of the adult population suffers from xerostomia. The clinical severity of the xerostomia demonstrated a strong relationship with the lower levels of UWS flow rate. Reduced levels of UWS flow rate in this study were also shown to be associated with dysphagia, fatigue, and increased DMF-T numbers. The data show that oral dryness, its associated desiccation symptoms and its clinical manifestations are significant health problems in Hungary. [source] Analytical modelling of users' behaviour and performance metrics in key distribution schemesEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2010Massimo Tornatore Access control for group communications must ensure that only legitimate users can access the authorised data streams. This could be done by distributing an encrypting key to each member of the group to be secured. To achieve a high level of security, the group key should be changed every time a user joins or leaves the group, so that a former group member has no access to current communications and a new member has no access to previous communications. Since group memberships could be very dynamic, the group key should be changed frequently. So far, different schemes for efficient key distribution have been proposed to limit the key-distribution overhead. In previous works, the performance comparison among these different schemes have been based on simulative experiments, where users join and leave secure groups according to a basic statistical model of users' behaviour. In this paper, we propose a new statistical model to account for the behaviour of users and compare it to the modelling approach so far adopted in the literature. Our new model is able to to lead the system to a steady state (allowing a superior statistical confidence of the results), as opposed to current models in which the system is permanently in a transient and diverging state. We also provide analytical formulations of the main performance metrics usually adopted to evaluate key distribution systems, such as rekey overheads and storage overheads. Then, we validate our simulative outcomes with results obtained by analytical formulations. Copyright © 2009 John Wiley & Sons, Ltd. [source] McGrath v Riddell: A flexible approach to the insolvency distribution rules?INTERNATIONAL INSOLVENCY REVIEW, Issue 1 2010Blanca Mamutse The rules relating to the division of the insolvent estate assume considerable importance in the field of international insolvencies, where different legal systems interact. International instruments including the European insolvency regulation and the UNCITRAL Model Law on Cross-Border Insolvency have provided a framework which governs the relationship between local and foreign distribution schemes. For English lawyers, questions remain however regarding the future role of the courts' statutory power to cooperate with the courts of ,relevant' countries or territories, and of the common law principle of universalism. An important issue connected to the determination of such questions is the established judicial approach to the pari passu rule, in the application of domestic law. This paper examines the manifestation of this tension in the litigation arising from the collapse of the HIH Casualty & General Insurance group of companies. It notes the scope which remains for continued resort to the statutory power of cooperation, and the potential for the Cross-Border Insolvency Regulations 2006 to encourage a more flexible approach to resolving differences between distribution schemes. Copyright © 2010 John Wiley & Sons, Ltd. [source] Managing QoS requirements for video streaming: from intra-node to inter-nodeINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 5 2006Y. Bai Abstract Streaming video over IP networks has become increasingly popular; however, compared to traditional data traffic, video streaming places different demands on quality of service (QoS) in a network, particularly in terms of delay, delay variation, and data loss. In response to the QoS demands of video applications, network techniques have been proposed to provide QoS within a network. Unfortunately, while efficient from a network perspective, most existing solutions have not provided end-to-end QoS that is satisfactory to users. In this paper, packet scheduling and end-to-end QoS distribution schemes are proposed to address this issue. The design and implementation of the two schemes are based on the active networking paradigm. In active networks, routers can perform user-driven computation when forwarding packets, rather than just simple storing and forwarding packets, as in traditional networks. Both schemes thus take advantage of the capability of active networks enabling routers to adapt to the content of transmitted data and the QoS requirements of video users. In other words, packet scheduling at routers considers the correlation between video characteristics, available local resources and the resulting visual quality. The proposed QoS distribution scheme performs inter-node adaptation, dynamically adjusting local loss constraints in response to network conditions in order to satisfy the end-to-end loss requirements. An active network-based simulation shows that using QoS distribution and packet scheduling together increases the probability of meeting end-to-end QoS requirements of networked video. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||