This paper describes the Web interface management infrastructure of a functioning network-computing system (PUNCH) that allows users to run unmodified simulation packages at geographically dispersed sites. The system ...
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This paper describes the Web interface management infrastructure of a functioning network-computing system (PUNCH) that allows users to run unmodified simulation packages at geographically dispersed sites. The system currently contains more than fifty university and commercial simulation tools, and has been used to carry out more than two hundred thousand simulations via the World Wide Web. Dynamically-constructed virtual URLs allow the Web interface management infrastructure to support the semantics associated with an interface to computing services without requiring any changes to Web browsers or WWW protocols. Virtual URLs also facilitate customizable control of access to networked resources. Simulation tools with text-based interfaces are supported via dynamically-generated, virtual interfaces, whereas tools with graphical interfaces are supported by leveraging available remote display-management technologies. Virtual interface generation and interactivity emulation are handled by a programmable state machine in conjunction with a mechanism to embed variables and objects within standard HTML.
The initial growth stage of GaN growth directly on basal plane sapphire substrate is investigated. Statistical experimental design is used for the optimization of processes with a large number of interwoven effects. T...
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The initial growth stage of GaN growth directly on basal plane sapphire substrate is investigated. Statistical experimental design is used for the optimization of processes with a large number of interwoven effects. The effects of growth conditions on elec.rical and surface morphology are analyzed by means of Hall mobility and atomic force microscopy. The interactions between Ga flux and nitrogen power during the buffer growth are discussed.
Dealing with global on-chip memory allocation/de-allocation in a dynamic yet deterministic way is an important issue for upcoming billion transistor multiprocessor System-on-a-Chip (SoC) designs. To achieve this, we p...
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ISBN:
(纸本)1581133383
Dealing with global on-chip memory allocation/de-allocation in a dynamic yet deterministic way is an important issue for upcoming billion transistor multiprocessor System-on-a-Chip (SoC) designs. To achieve this, we propose a new memory management hierarchy called Two-Level Memory Management. To implement this memory management sch.me - Which presents a paradigm shift in the way designers look at on-chip dynamic memory allocation - We present a System-on-a-Chip Dynamic Memory Management Unit (SoCDMMU) for allocation of the global on-chip memory, which we refer to as level two memory management (level one is the operating system management of memory allocated to a particular on-chip processor). In this way, heterogeneous processors in an SoC can request and be granted portions of the global memory in twenty clock cycles in the worst case for a four-processor SoC, which is at least an order of magnitude faster than software-based memory management. We present a sample implementation of the SoCDMMU and compare hardware and software implementations.
The output characteristics, cutoff frequency, breakdown voltage and the transconductance of wurtzite and zincblende phase GaN MESFETs have been calculated using a self-consistent, full band Monte Carlo simulation. It ...
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The output characteristics, cutoff frequency, breakdown voltage and the transconductance of wurtzite and zincblende phase GaN MESFETs have been calculated using a self-consistent, full band Monte Carlo simulation. It is found that the calculated breakdown voltage for the wurtzite device is considerably higher than that calculated for a comparable GaN zincblende phase device. The zincblende device is calculated to have a higher transconductance and cutoff frequency than the wurtzite device. The higher breakdown voltage of the wurtzite phase device is attributed to the higher density of elec.ronic states for this phase compared to the zincblende phase. The higher cutoff frequency and transconductance of the zincblende phase GaN device is attributed to more appreciable elec.ron velocity overshoot for this phase compared to that for the wurtzite phase. The maximum cutoff frequency and transconductance of a 0.1 μm gate-length zincblende GaN MESFET are calculated to be 220GHz and 210 mS/mm, respectively. The corresponding quantities for the wurtzite GaN device are calculated to be 160GHz and 158 mS/mm.
Banding is an image artifact that appears as peroidic light and dark bands across a page. This paper presents an experimental study on the application of a piezoelec.ric laser beam deflection device to reduce banding ...
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Banding is an image artifact that appears as peroidic light and dark bands across a page. This paper presents an experimental study on the application of a piezoelec.ric laser beam deflection device to reduce banding in the elec.rophotographic process. Banding is characterized using several different measurement techniques. An empirical model of the actuator is obtained using system identification techniques by measuring the laser beam position on-line using an optical sensor. An open loop control strategy is then proposed and implemented. Experimental results showed significant improvements with the images printed using beam deflection control.
In interactive multimedia presentations, users should have the flexibility to decide on various scenarios they want to see. This means that two-way communications should be captured by the conceptual model. An abstrac...
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ISBN:
(纸本)0964345692
In interactive multimedia presentations, users should have the flexibility to decide on various scenarios they want to see. This means that two-way communications should be captured by the conceptual model. An abstract semantic model, the augmented transition network (ATN), is proposed for modeling user interactions in multimedia presentations. In ATNs, each state node allows multiple outgoing arcs to model potential user interactions. At the decision point, the multimedia presentation system can use this information to display selec.ion buttons so users can make their choices. The superiority of modeling user interactions with ATN instead of the Timeline model or the Object Composition Petri Net model is discussed in this paper. Our results show that the ATN is effective for modeling user interactions in a multimedia presentation environment.
In this paper, we propose and analyze a simple adaptive uplink power control sch.me, called two-level channel inversion, for data traffic in a cellular CDMA system. The basic idea is to reduce out-cell interference by...
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In this paper, we propose and analyze a simple adaptive uplink power control sch.me, called two-level channel inversion, for data traffic in a cellular CDMA system. The basic idea is to reduce out-cell interference by reducing the rate of, or even suspending, transmission when the wireless channel is in a bad condition. We first describe the sch.me in detail, and then present a probabilistic analysis model for evaluating the system performance. With this model, we determine the queueing delay and system throughput. Numerical results show that in comparison with the traditional channel inversion sch.me, the two-level channel inversion sch.me can substantially improve system throughput at a moderate cost of extra queueing delay. Finally, we present a design algorithm to optimize the overall performance while maintaining each user's quality of service (QoS).
We propose a system to reduce elec.rophotographic laser printer banding artifacts due to optical photoconductor (OPC) drum velocity fluctuations. The drum velocity fluctuations are sensed with an optical encoder mount...
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We propose a system to reduce elec.rophotographic laser printer banding artifacts due to optical photoconductor (OPC) drum velocity fluctuations. The drum velocity fluctuations are sensed with an optical encoder mounted on the drum axis. Based on the line-to-line differential encoder count, we modulate the laser pulse width to compensate fluctuations in development that would otherwise occur. We present an analysis of the system, including the compensation algorithm that determines the desired pulse-width as a function of differential encoder count. Characterization of the system is based on printing, scanning, and processing a special test page that yields information about line-spacing and absorptance fluctuations. This data is synchronized with the encoder count signal that was recorded during the printing of the test page. Finally, we present experimental results for an HP LaserJet 4M printer that demonstrate the efficacy of the system in reducing banding due to OPC drum velocity fluctuations.
This paper provides an overview of the current status of engineering education in the United Kingdom. A comparison of traditional undergraduate and post-graduate engineering programmes offered by universities and tech...
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This paper provides an overview of the current status of engineering education in the United Kingdom. A comparison of traditional undergraduate and post-graduate engineering programmes offered by universities and technical polytechnics against proposed engineering & technology programs is highlighted in view of recent changes. In addition, current issues including student enrolment and graduates' professional development are described.
Erbium-doped films were grown on sapphire and silicon substrates by reactive sputtering, with different Er concentrations in the film. GaN films deposited at 800 K were determined to be polycrystalline by x-ray diffra...
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Erbium-doped films were grown on sapphire and silicon substrates by reactive sputtering, with different Er concentrations in the film. GaN films deposited at 800 K were determined to be polycrystalline by x-ray diffraction analysis, and retained their polycrystalline structure after annealing in nitrogen at 1250 K. The Er-doped films showed optical transmission beginning at about 360 nm, and the Er dose and film purity were determined with Rutherford backscattering spectroscopy. Photoluminescence and cathodoluminescence spectroscopy showed sharp emission lines corresponding to Er3+ intra 4fn shell transitions over the range from 9 - 300 K. At above-bandgap optical and elec.ron excitation, the 4S3/2 and 4F9/2 transition dominate, and are superposed on the "yellow band" emission. The infrared emission line at 1543 nm, corresponding to the Er 4I13/2 to 4I 5/2 transition is also observed.
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