One of the most promising approaches for high speed networks for integrated service applications is fast packet switching, or ATM (asynchronous transfer mode). ATM can be characterized by very high speed transmission ...
详细信息
One of the most promising approaches for high speed networks for integrated service applications is fast packet switching, or ATM (asynchronous transfer mode). ATM can be characterized by very high speed transmission links and simple, hard-wired protocols within a network. To match the transmission speed of the network links, and to minimize the overhead due to the processing of network protocols, the switching of cells is done in hardware switching fabrics in ATM networks. A number of designs have been proposed for implementing ATM switches. Although many differences exist among the proposals, the vast majority of them are based on self-routeing multi-stage interconnection networks. This is because of the desirable features of multi-stage interconnection networks such as self-routeing capability and suitability for VLSI implementation. Existing ATM switch architectures can be classified into two major classes: blocking switches, where blockings of cells may occur within a switch when more than one cell contends for the same internal link, and non-blocking switches, where no internal blocking occurs. A large number of techniques have also been proposed to improve the performance of blocking and non-blocking switches. In this paper, we present an extensive survey of the existing proposals for ATM switch architectures, focusing on their performance issues.
This paper describes an installation of the fringe scanning method into a shadow-type Moire Topography. The result is a high-precision three-dimensional measuring system and automatic fringe order measuring system usi...
详细信息
A method of reducing overhead caused by the processor synchronization process and common memory access in finely grained tasks is described. The authors propose a hardware configuration to eliminate the synchronizatio...
详细信息
A method of reducing overhead caused by the processor synchronization process and common memory access in finely grained tasks is described. The authors propose a hardware configuration to eliminate the synchronization time and a scheduler which minimizes the redundant accesses to shared memory. The proposed scheduler algorithm is processed in parallel. The processes share the common upper bound and the lower bound function which includes the preparation time for shared memory access. The effectiveness of the proposed scheme was confirmed by applying it to the computation of Newton-Euler equations for dynamic arm control, using a multiple digital signal processing system with four TMS320C25 processors.< >
The authors describe various state estimation methods of a quantized sound environmental system. The elimination of not only the usual background noise but also the quantization noise owing to digital observation is d...
详细信息
The authors describe various state estimation methods of a quantized sound environmental system. The elimination of not only the usual background noise but also the quantization noise owing to digital observation is discussed. The methods include the traditional Kalman filter as a special case when Gaussian distribution is employed and where there is no level quantization. The level quantization mechanism is discussed from the statistical viewpoint and from the deterministic viewpoint. The methods presented can estimate any kind of statistic, including the lower and the higher order moments from the level quantized observation data. Not only the linear correlation but also the higher order nonlinear correlations between a state variable and a quantized observation are hierarchically used in the estimation algorithm. The quantized observation data are used in the linear and nonlinear forms. The effectiveness of the proposed methods was confirmed experimentally by applications to room acoustics data.< >
An on-line scheme to failure diagnosis is proposed for dynamic systems under adaptive control, which is designed based on a direct approach to self-tuning regulator. Failure modes occurred in the system are assumed to...
详细信息
An on-line scheme to failure diagnosis is proposed for dynamic systems under adaptive control, which is designed based on a direct approach to self-tuning regulator. Failure modes occurred in the system are assumed to be described by unexpected changes in physical parameters of the system. The parameter changes in the controlled system can effectively be detected by using Kullback Discrimination Information (KDI) as an index for model discrimination. In order to decide whether the detected system parameter change is caused by a failure or not, a fuzzy inference approach to failure decision is considered. Some appropriate membership functions which describe fuzzy events of failures are constructed to perform the fuzzy inference. In this way, useful knowledge about failure modes which is available from, e.g., experts can be introduced into the model- based diagnosis technique. Simulation studies of a second-order damped oscillator have been carried out to demonstrate the effectiveness of the method.
The phase analysis of fringes by apptying moife techniques to the interferometer is well-known. Since this method is based on 2-D subtraction method in the incoherent optics, the distortion of the optical system is ea...
详细信息
Kerr electro-optic field mapping measurements using the sensitive AC modulation method were made in liquid nitrogen. The steady-state electric fields between parallel stainless steel electrodes that had a gap of 7 mm ...
详细信息
Kerr electro-optic field mapping measurements using the sensitive AC modulation method were made in liquid nitrogen. The steady-state electric fields between parallel stainless steel electrodes that had a gap of 7 mm are shown to be essentially uniform for voltages up to 70 kV with no significant space charge distortion. The Kerr constant B of liquid nitrogen is constant over the AC modulation frequency range of 1-20 kHz, while increasing above 20 kHz. This change of B with the modulation frequency coincides with the frequency-amplitude gain characteristic of the lock-in amplifier used, so that B is independent of the AC modulation frequency within the range of this study. B monotonically decreases with increasing temperature, T, thus decreasing liquid nitrogen density, rho , so that B is related linearly to rho /T. The polarizability anisotropy of liquid nitrogen is evaluated to be 8.3*10/sup -41/ F-m/sup 2/ from the slope of the B-( rho /T) characteristic, obtained from a simple physical model.< >
Hydrogenated microcrystalline silicon (μ c -Si:H) which contains very small silicon microcrystals surrounded by hydrogen atoms can be fabricated by RF sputtering in pure hydrogen onto a low temperature (about 100 K) ...
详细信息
Hydrogenated microcrystalline silicon (μ c -Si:H) which contains very small silicon microcrystals surrounded by hydrogen atoms can be fabricated by RF sputtering in pure hydrogen onto a low temperature (about 100 K) substrate. Properties of our μ c -Si:H are derived from three-dimensional quantum size effects in the alloys, and they are quite different from those of the conventional μ c -Si:H. We may interpret a growth mechanism for such an interesting μ c -Si:H material, that microcrystals are formed under the hydrogen plasma by the reaction among SiH x ( x = 1, 2, 3) species and hydrogen radicals without obtaining thermal energy from the substrate, and then physically deposited on it. The reasons are that our μ c -Si:H is fabricated on a low temperature substrate, and that SiH 2 configuration exists on the microcrystalline surface from the infrared absorption measurement. This model can well explain our experimental results.
Basic research for the micro actuator using TiNi Shape Memory Alloy (SMA) is conducted from the crystallographic point of view. SMA (TiNi) thin film is fabricated by sputtering deposition. First, the influence of subs...
详细信息
暂无评论