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21.
A Survey of Handover Techniques for Wireless ATM Networks 总被引:1,自引:0,他引:1
This paper provides a review and comprehensivecomparison of existing handover schemes proposed forwireless ATM networks. Existing schemes include thoseproposed by NEC, Olivetti, Bell Labs, Cambridge, Stanford, CMU, Berkeley, Michigan, VTT, andColumbia. We highlight the methodologies employed by thevarious schemes and reveal their differences. We discussissues related to the effect of ATM switch architectures on mobility implementation and on futurehandover paradigms. 相似文献
22.
Garimella S.V. Joshi Y.K. Bar-Cohen A. Mahajan R. Toh K.C. Carey V.P. Baelmans M. Lohan J. Sammakia B. Andros F. 《Components and Packaging Technologies, IEEE Transactions on》2002,25(4):569-575
The presentations made, as well as the discussions, in the panels at the workshop, Thermal Challenges in Next Generation Electronic Systems (THERMES), are summarized in this paper. The panels dealt with diverse topics including thermal management roadmaps, microscale cooling systems, numerical modeling from the component to system levels, hardware for future high performance and Internet computing architectures, and transport issues in the manufacturing of electronic packages. The focus of the panels was to identify barriers to further progress in each area that require the attention of the research community. 相似文献
23.
Lu P.-F. Warnock J.D. Cressler J.D. Jenkins K.A. Toh K.-Y. 《Electron Devices, IEEE Transactions on》1991,38(6):1410-1418
The device design and performance of double-poly self-aligned p-n-p technology, featuring a low-resistivity p+ subcollector, thin p-epi, and boron-doped poly-emitter are described. Device isolation is provided by deep and shallow trenches which reduce the collector-to-substrate capacitance while maintaining a high breakdown voltage (⩾40 V). By utilizing a shallow emitter process in conjunction with an optimized arsenic-base implant, devices with emitter-base junction depths as shallow as 20 nm and base widths of less than 100 nm were obtained. Cutoff frequencies of up to 27 GHz were obtained, and the AC performance was demonstrated by an NTL-gate delay of 36 ps and an active-pull-down (APD) ECL-gate delay of 20 ps. This high-performance p-n-p technology was developed to be compatible with existing double-poly n-p-n technologies. The matching speed of p-n-p devices opens up new opportunities for high-performance complementary bipolar circuits 相似文献
24.
Francisco J. Martinez Manuel Fogue C. K. Toh Juan-Carlos Cano Carlos T. Calafate Pietro Manzoni 《Wireless Personal Communications》2013,69(2):639-663
Researchers in vehicular ad hoc networks (VANETs) commonly use simulation to test new algorithms and techniques. This is the case because of the high cost and labor involved in deploying and testing vehicles in real outdoor scenarios. However, when determining the factors that should be taken into account in these simulations, some factors such as realistic road topologies and presence of obstacles are rarely addressed. In this paper, we first evaluate the packet error rate (PER) through actual measurements in an outdoor road scenario, and deduce a close model of the PER for VANETs. Secondly, we introduce a topology-based visibility scheme such that road dimension and geometry can be accounted for, in addition to line-of-sight. We then combine these factors to determine when warning messages (i.e., messages that warn drivers of danger and hazards) are successfully received in a VANET. Through extensive simulations using different road topologies, city maps, and visibility schemes, we show these factors can impact warning message dissemination time and packet delivery rate. 相似文献
25.
Li Yanping Wang Xin Xue Xiangyang C. K. Toh 《电子科学学刊(英文版)》2006,23(5):650-655
Although clustering is a convenient framework to enable traffic control and service support in Mobile Ad hoc NETworks (MANETs), it is seldom adopted in practice due to the additional traffic overhead it leads to for the resource limited ad hoc network. In order to address this problem, we proposed a loop-based approach to combine clustering and routing. By employing loop topologies, topology information is disseminated with a loop instead of a single node, which provides better robustness, and the nature of a loop that there are two paths between each pair of nodes within a loop composed of setup procedure, regular procedure and emergent route recovering. suggests smart route recovery strategy. Our approach is recovery procedure to achieve clustering, routing and 相似文献
26.
Theoretical and Experimental Insight into the Mechanism for Spontaneous Vertical Growth of ReS2 Nanosheets 下载免费PDF全文
Debjit Ghoshal Anthony Yoshimura Tushar Gupta Andrew House Swastik Basu Yanwen Chen Tianmeng Wang Yang Yang Wenjia Shou Jordan A. Hachtel Juan Carlos Idrobo Toh‐Ming Lu Sagnik Basuray Vincent Meunier Su‐Fei Shi Nikhil Koratkar 《Advanced functional materials》2018,28(30)
Rhenium disulfide (ReS2) differs fundamentally from other group‐VI transition metal dichalcogenides (TMDs) due to its low structural symmetry, which results in its optical and electrical anisotropy. Although vertical growth is observed in some TMDs under special growth conditions, vertical growth in ReS2 is very different in that it is highly spontaneous and substrate‐independent. In this study, the mechanism that underpins the thermodynamically favorable vertical growth mode of ReS2 is uncovered. It is found that the governing mechanism for ReS2 growth involves two distinct stages. In the first stage, ReS2 grows parallel to the growth substrate, consistent with conventional TMD growth. However, subsequent vertical growth is nucleated at points on the lattice where Re atoms are “pinched” together. At such sites, an additional Re atom binds with the cluster of pinched Re atoms, leaving an under‐coordinated S atom protruding out of the ReS2 plane. This under‐coordinated S is “reactive” and binds to free Re and S atoms, initiating growth in a direction perpendicular to the ReS2 surface. The utility of such vertical ReS2 arrays in applications where high surface‐to‐volume ratio and electric‐field enhancement are essential, such as surface enhanced Raman spectroscopy, field emission, and solar‐based disinfection of bacteria, is demonstrated. 相似文献
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29.
We proposed the endogenous thrombin potential (ETP) as an overall function test of the coagulation system. We recently introduced a routine test which requires defibrinated plasma. In order to develop an assay in which the ETP-value can be directly obtained by measuring the optical density, we investigated two methods to inhibit fibrinogen clottability and to inactivate alpha2-macroglobulin. The first method makes use of hydroxylamine to inactivate alpha2-macroglobulin and H-Gly-Pro-Arg-Pro-OH to inhibit fibrin polymerization. At pH 7.35, plasma incubated with 25 mM hydroxylamine and 1.5 mg/mL H-Gly-Pro-Arg-Pro-OH for 5 minutes at 37 degrees C resulted in a reduced endlevel of the amidolytic activity on small chromogenic substrates. The second method uses a metalloprotease purified from Crotalus basiliscus to remove alpha2-macroglobulin from plasma in combination with H-Gly-Pro-Arg-Pro-OH. Herein plasma is incubated with 3.5 LM protease during 15 minutes at 37 degrees C in the presence of 1 mg/mL polymerization inhibitor. The enzymatic method results in a zero endlevel of the amidolytic activity and this would imply that measurement of the ETP is reduced to an endpoint determination of the optical density. We show that the endpoint determination of the optical density correlates well with the calculated ETP in plasmas with different degrees of anticoagulation. 相似文献
30.
The presence of a high temperature (>Tg) relaxation in amorphous polystyrene has been investigated further. In the previous work,1 the techniques of differential thermal analysis (DTA) and torsional braid analysis (TBA) were employed to study polystyrene as a function of “monodisperse” molecular weight. The occurrence of the Tll transition appeared to be associated with the attainment of a critical viscosity level with also corresponded with a free volume level. An entanglement network developed at a critical value of molecular weight, Mc, giving a break in the Tll-versus-M plots. The present work deals with the influence of dispersity on the Tll transition, below and above Mc. A series of binary blends of “monodisperse” anionically polymerized polystyrenes with systematic changes in M?n and heterogeneity index (M?w/M?n) was tested by TBA. The results show that when both components have molecular weights below Mc, single and average values of Tg and Tll are observed which are linearly related to M?n?1, as predicted by free volume arguments. Although a single Tg is observed when one component has a molecular weight above and the other has a molecular weight below Mc, the components appear to undergo the Tll relaxation independently. The results indicate that both the glass transition and the Tll transition are basically governed by the same type of molecular motion but at different length ranges. 相似文献