The codesign of embedded real-time signal processing systems is complex. In certain application domains requiring high computational throughput, this complexity is due to the need to employing parallel processing and ...
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(纸本)1581133383
The codesign of embedded real-time signal processing systems is complex. In certain application domains requiring high computational throughput, this complexity is due to the need to employing parallel processing and perhaps using heterogeneous processors. The use of commercial-off-the-shelf (COTS) multiprocessor (MP) hardware and software can reduce codesign complexity. Further complexity reduction can be obtained with emerging synthesis frameworks, which can generate deployable code by leveraging vendor communication and computation libraries. However, these synthesis frameworks are inadequate in providing a sound specification and design methodology (SDM) because they require the designer to first choose the implementation target before specification and design exploration. We have developed a new SDM known as MAGIC that allows the designer to capture the specification in an executable model that can then be used in design exploration to find the optimal COTS MP technology and architecture before committing to that technology. The MAGIC SDM exploits emerging open-standards based VSIPL computation middleware and MPI communication middleware to provide connectivity between specification and design with synthesis frameworks for implementation. This SDM is also shown to be applicable to the system-on-chip (SOC) domain, especially as embodied in a new framework called Virtual Component Co-design from Cadence Design Systems.
A series of experiments were performed to explore the growth of InN by Molecular Beam Epitaxy (MBE). The growth conditions were optimized based on the study of RHEED during growth and InN dissociation experiments. Cha...
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A series of experiments were performed to explore the growth of InN by Molecular Beam Epitaxy (MBE). The growth conditions were optimized based on the study of RHEED during growth and InN dissociation experiments. Characterization of the InN thin films were performed by various techniques such as TEM and XRD.
AlGaN/GaN heterostructures were grown on LiGaO2 (LGO), sapphire, and hydride vapor phase epitaxy (HVPE) grown GaN substrates. Structural properties and surface morphology of each film was compared. LGO substrates prod...
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AlGaN/GaN heterostructures were grown on LiGaO2 (LGO), sapphire, and hydride vapor phase epitaxy (HVPE) grown GaN substrates. Structural properties and surface morphology of each film was compared. LGO substrates produced the lowest FWHM values for both symmetric 〈00.4〉 and asymmetric 〈10.5〉 reflections. The films grown on LGO substrate also showed the best morphology. The small lattice mismatch of LGO to nitrides and Ga-polarity of grown films could be the primary reason for the smoother surface of AlGaN/GaN structure on LGO substrates. In developing the HFET structure on the LGO substrate, we have observed step flow growth in a structure with 300 angstroms thick Al0.25Ga0.75N on 2.4 μm thick GaN, which is very similar to the films grown by MOCVD. A high III/V flux ratio during growth and recently improved polishing of LGO substrates may have aided in promoting two dimensional step flow growth.
Compliant substrates offer a new approach for strain management in semiconductors. Various implementations and processes for achieving substrate compliancy have been proposed and demonstrated. These include the use of...
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Compliant substrates offer a new approach for strain management in semiconductors. Various implementations and processes for achieving substrate compliancy have been proposed and demonstrated. These include the use of twist-, glass-, and metal-bonds. A recent focus in our work has been on the growth of GaN on a novel and easily removable substrate-lithium gallate-for the ultimate regrowth on a bonded GaN template. The bonding technology is important to reduce thermal stresses during the regrowth step. Herein, we focus on the understanding of the growth of GaN on lithium gallate.
In this paper we have reported the observation of visible photoluminescence (PL) and cathodoluminescence (CL) of Pr implanted in GaN. The implanted samples were given isochronal thermal annealing treatments at a tempe...
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In this paper we have reported the observation of visible photoluminescence (PL) and cathodoluminescence (CL) of Pr implanted in GaN. The implanted samples were given isochronal thermal annealing treatments at a temperature of 1100° C in NH3, N2, Ar2, and in forming gas N2 +H2, at atmospheric pressure to recover implantation damages and activate the rare earth ions. The sharp characteristic emission Unes corresponding to Pr3+ intra-4fn -shell transitions are resolved in the spectral range from 350 nm to 1150 nm, and observed over the temperature range of 12 K-335 K. The PL and CL decay kinetics measurement was performed for 3P1, 3P0 and 1D2 levels.
A common assumption in iterative learning control (ILC) is that the initial states in each repetitive operation should be inside a given ball centred at the desired initial states. This assumption is critical to the s...
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A common assumption in iterative learning control (ILC) is that the initial states in each repetitive operation should be inside a given ball centred at the desired initial states. This assumption is critical to the stability analysis, and the size of the ball will directly affect the final output-trajectory tracking errors. However, the initial state may be unobtainable. In this paper, the assumption can be removed by using a high-order initial-state learning sch.me together with a high-order D-type ILC updating law. Nonlinear time-dependent uncertain systems are investigated. Uniform bounds of the tracking errors are obtained. These bounds depend only on the bounds of the differences of the uncertainties and disturbances between two successive system repetitions, and not on the re-initialization errors. The unknown desired initial states can be identified through learning iterations. Furthermore, better learning transient behaviour can be expected as the iteration number increases, by using the high-order sch.me. This result is illustrated by simulations.
This paper presents a method for the selec.ion of test sequences from statecharts. It is shown that a statechart can be transformed into a flow graph modelling the flow of both control and data in the statechart. The ...
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This paper presents a method for the selec.ion of test sequences from statecharts. It is shown that a statechart can be transformed into a flow graph modelling the flow of both control and data in the statechart. The transformation enables the application of conventional control and data flow analysis techniques to test sequence selec.ion from statecharts. The resulting set of test sequences provides the capability of determining whether an implementation establishes the desired flow of control and data expressed in statecharts.
OzGateway is a cooperative database system designed for integrating heterogeneous existing information systems into an interoperable environment. It also aims to provide a gatewway for legacy information system migrat...
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OzGateway is a cooperative database system designed for integrating heterogeneous existing information systems into an interoperable environment. It also aims to provide a gatewway for legacy information system migration. This paper summarises the problems and results of multidatabase transaction management research. In supporting global updates in OzGateway in an evolutionary way, we introduce a classification of multidatabase transactions and discuss the problems in each category. The architecture of OzGateway and the design of the global transaction manager and servers are presented.
Thermodynamic properties and phase diagrams of the Fe-C-P system have been assessed based on thermodynamic models. The regular solution type model has been employed for the liquid phase and the two-sublattice model fo...
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Thermodynamic properties and phase diagrams of the Fe-C-P system have been assessed based on thermodynamic models. The regular solution type model has been employed for the liquid phase and the two-sublattice model for the solid phases in the Fe-C-P system. The thermodynamic model parameters for the individual phases of this system have been evaluated from relevant experimental information available in the literature, using a computerized optimization technique. Several isothermal and vertical sections as well as a liquidus surface projection are calculated using the evaluated parameters, showing reasonable agreement with reported data from various sources. In comparison with a previous assessment known from the literature, the present one provides a better description for the thermodynamic behavior of the liquid phase.
Explosive forming is metal forming method using underwater shock wave generated by underwater explosion of explosive. This technique is superior to static forming techniques on the duplication of the shape of the die,...
Explosive forming is metal forming method using underwater shock wave generated by underwater explosion of explosive. This technique is superior to static forming techniques on the duplication of the shape of the die, because the metal plate can obtain a great work-hardening. It is not necessary upper die used for static forming techniques such us the press forming. Moreover, this technique can use not only metals but also resins, plaster and paper as the material of die. As a result, this technique is suitable for production of many kinds and quantity products. We have developed the equipment for lower costs of metal forming obtained appointed shape using underwater explosive forming technique. As a new method, we have considered the free forming. Therefore, in this paper, we pick up some models for free forming of underwater explosive forming. We have made numerical simulation on these models. The results of numerical simulation were discussed.
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