8,962 research outputs found
On maximizing the throughput of opportunistic multicast in wireless cellular networks with erasure codes
In this paper, we discuss the opportunistic multicast scheduling (OMS) in a wireless network using erasure codes. Originally proposed for channels with erasures such as internet, erasure codes are found useful in wireless multicast to achieve better tradeoff between multiuser diversity and the multicast gain. In this work we investigated how to design an opportunistic multicast scheduling scheme which can efficiently improve the per user throughput capacity in a wireless network using erasure codes. Aiming at maximize the throughput, we proposed a maximal OMS (M-OMS) scheme which is inspired by the unicast maximal opportunistic scheduling. We build a system model and provide theoretical analysis on proposed M-OMS scheme. The proposed scheme shows substantial improvement over existing fixed selection ratio opportunistic multicast scheduling schemes (F-OMS). © 2011 IEEE.published_or_final_versionThe 2011 IEEE International Conference on Communications (ICC 2011), Kyoto, Japan, 5-9 June 2011. In Proceedings of the IEEE ICC, 2011, p. 1-
POPIM: Pragmatic online project information management for collaborative product development
POPIM (Pragmatic Online Project Information Management) is a prototype web-based platform for managing collaborative product development projects within an extended enterprise environment. A suite of facilities are provided for geographically dispersed project team members to communicate, share, and collaborate on a project in a common workspace where they enjoy online access to the most up to date project information and maintain a high-level data consistency and accumulate experience and knowledgebase. In addition to standard project management functionality such as defining work structure breakdowns, determining work schedules, teaming up with specialists, and allocating resources, POPIM incorporates workflow management (including dependency management), and deliverable management (document management if documents are considered as one kind of deliverables). Individual members have their personalized accounts according to their skills and roles/responsibilities in a project. A project team and its members may maintain their own journals/records. More application-specific functions such as product design review and engineering change management can be implicitly performed through online document forms.published_or_final_versio
Web-based product design review: Implementation perspective
Product design review is one of the typical scenarios of collaborative product development. We developed a web-based prototype framework for supporting the collaborative tele-product design review on the Internet. It provides a suite of tools to establishing and management the new product design review process. This paper discusses the issues related to the development and implementation of web application in prototype implication. The typical 3-tier architecture is explained to show how the CyberReview components work together to achieve the intended functionality. The VRML EAI and Java Applet-Servlet pair technology was included to support the implication.published_or_final_versio
Optimization of C/TiCx duplex diffusion barrier coatings for SiCf/Ti composites based on interfacial structure evolution exploration
Introducing a carbon single coating is a popular method used to protect SiCf/Ti composites from severe interface reactions. However, carbon coatings lose their protective effect on SiC fibres at high temperature, even after a short period time. As such, given the strong demand for high temperature applications in aeronautics and astronautics a more coating which is more effective at high temperatures is desirable. In order to improve the high temperature interfacial stability of SiCf/Ti composites, a C/TiCx duplex coating system with different C contents in TiCx was introduced to explore the protection of fibres at 1200 °C for 1 h. The results show that the C/quasi-stoichiometric TiC coating system protects the SiC fibres most effectively. Based on insights from the evolution of the interface structure, TiCx has been identified as an interfacial reaction product from the C single coating, exhibiting a gradient in C content and grain size, which is different from a deposited TiC layer with a well-distributed composition and structure. The different coating structure gives rise to different ability to resist C diffusion at high temperatures, in which poor resistance ability appears in TiCx interfacial reaction layer coming from C single coating due to short-circuit diffusion in C-rich fine-grained TiC layer and fast intracrystalline diffusion trigged by amounts of vacancies in sub-stoichiometric coarse-grained TiC layer. Therefore, C/quasi-stoichiometric TiC duplex coatings with a thick, coarse-grained quasi-stoichiometric TiC layer could effectively inhibit C diffusion by comparison to C single coatings, and is more effective than C/rich-carbon TiC duplex coatings due to the existence of short-circuit diffusion in the latter. As such, C/quasi-stoichiometric TiC duplex coatings appear to be an optimal diffusion barrier for SiCf/Ti composites at high temperature
Fringe electric fields of flat and cylindrical deflectors inelectrostatic charged particle storage rings
Analytic expressions for the potentials and fields of flat and cylindrical plates, including the fringe fields, are given. The present analysis extends and simplifies the current expression for the fields of flat plates and develops expressions for the fringe fields of cylindrical plates in terms of polar coordinates. The development of a FORTRAN program to output the field strength at a given location within the Proton Electric Dipole Moment (Proton EDM) ring is then described. Fourth-order Runge-Kutta integration is used to investigate the effect of fringe fields on particle and spin dynamics with precision tracking in the proposed Proton EDM experiment.1331sciescopu
Thermodynamic and kinetics of hydrogen photoproduction enhancement by concentrated sunlight with CO2 photoreduction by heterojunction photocatalysts
For achieving water splitting into hydrogen under sunlight for practical applications, the high efficiencies of the photoreduction of CO2 over TiO2/Fe3O4 photocatalysts combined with hydrogenation of water splitting over Pt/TiO2 were investigated by practical concentrated solar energy compared with Hg lamp and Xe lamp. Based on AI analysis on the influence factors, the key parameters for TOC concentration were photocatalysts, Na2CO3 concentration and radiation intensity while the key parameters for hydrogen production were photocatalysts, radiation intensity, and TOC concentration. Accordingly, the mechanism of concentrated sunlight effects has been discussed from the view of thermodynamics and kinetics. The concentrated sunlight provides a simultaneous supply of sufficient electron–hole pairs and thermal energy. Water to hydrogen and CO2 reduction are both enhanced in concentrated sunlight due to endothermal reactions. Doping changes the internal electric field of p-n junction of in different possible ways, and thus composite photocatalysts with favorable formation of p-n junctions would enhance the charge separation by internal electric field. Moreover, photocatalysts are beneficial for providing more excited electrons at a time for achieving CO2 photoreduction at the surface region of the particles with higher density of radiation by concentrated solar energy. Subsequently, products from CO2 photoreduction, acting as sacrificial electron donors, improved hydrogen evolution in solar-mediated water splitting for prohibiting reverse reactions
Classification of migraine stages based on resting-state EEG power
© 2015 IEEE. Migraine is a chronic neurological disease characterized by recurrent moderate to severe headaches during a period like one month often in association with symptoms in human brain and autonomic nervous system. Normally, migraine symptoms can be categorized into four different stages: inter-ictal, pre-ictal, ictal, and post-ictal stages. Since migraine patients are difficulty knowing when they will suffer migraine attacks, therefore, early detection becomes an important issue, especially for low-frequency migraine patients who have less than 5 times attacks per month. The main goal of this study is to develop a migraine-stage classification system based on migraineurs' resting-state EEG power. We collect migraineurs' O1 and O2 EEG activities during closing eyes from occipital lobe to identify pre-ictal and non-pre-ictal stages. Self-Constructing Neural Fuzzy Inference Network (SONFIN) is adopted as the classifier in the migraine stages classification which can reach the better classification accuracy (66%) in comparison with other classifiers. The proposed system is helpful for migraineurs to obtain better treatment at the right time
Substance P induces localization of MIF/α1-inhibitor-3 complexes to umbrella cells via paracellular transit through the urothelium in the rat bladder
BACKGROUND: Macrophage migration inhibitory factor (MIF) is released into the intraluminal fluid during bladder inflammation in the rat complexed to α1-inhibitor-3 (A1-I3; a rodent proteinase inhibitor in the α-macroglobulin family). The location of A1-I3 in the bladder had not been investigated. Therefore, we examined the location of A1-I3 and MIF/A1-I3 complexes in the bladder and changes due to experimental inflammation. METHODS: Anesthetized male rats had bladders removed with no treatment (intact) or were injected with Substance P (SP; s.c.; saline vehicle). After one hour intraluminal fluid was removed, bladder was excised and MIF and A1-I3 levels were determined using ELISA and/or western-blotting. MIF co-immunoprecipitation determined MIF/A1-I3 complexes in the bladder. Bladder sections were immunostained for A1-I3 and MIF/A1-I3. RESULTS: A1-I3 immunostaining was observed in interstitial spaces throughout the bladder (including submucosa) but not urothelium in intact and saline-treated rats. RT-PCR showed that the bladder does not synthesize A1-I3, therefore, A1-I3 in the interstitial space of the bladder must be plasma derived. In SP-treated rats, A1-I3 in the bladder increased and A1-I3 was observed traversing through the urothelium. Umbrella cells that do not show MIF and/or A1-I3 immunostaining in intact or saline-treated rats, showed co-localization of MIF and A1-I3 after SP-treatment. Western blotting demonstrated that in the bladder MIF formed non-covalent interactions and also binds covalently to A1-I3 to form high molecular weight MIF/A1-I3 complexes (170, 130 and 75-kDa, respectively, verified by co-immunoprecipitation). SP-induced inflammation selectively reduced 170-kDa MIF/A1-I3 in the bladder while increasing 170 and 130-kDa MIF/A1-I3 in the intraluminal fluid. CONCLUSION: A1-I3 and MIF/A1-I3 complexes are resident in bladder interstitium. During SP-induced inflammation, MIF/A1-I3 complexes are released from the bladder into the lumen. Binding of MIF/A1-I3 complexes to urothelial cells during inflammation suggests these complexes participate in the inflammatory reaction through activation of receptors for MIF and/or for A1-I3
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