ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677693

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Accurate current analysis is required in circuit designs to analyze electromigration failure rate, power consumption, voltage drops, etc. A new current model for CMOS gates is presented in this paper. The current waveform of a CMOS gate during a transition consists of three components: (1) Differential gate capacitor currents, (2) charging currents for load capacitance, and (3) short‐circuit currents. The first one occurs when input changes and the others exist only when the output changes. Hence this model can generate negative current waveform, like SPICE. These three components are characterized with triangular functions with four parameters which can be easily obtained after a timing simulation. This model can be used in any switch‐level timing simulators to generate current waveforms. The simulated current waveform, instead of the average estimation, helps solve VLSI reliability problems due to the electromigration and excess voltage drops in the power buses. When comparing the results obtained by using SPICE and our model, we can find that agreement occurs, especially between the time points of current pulses.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677694

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A scheme, based on the four‐layer inhomogeneous spherical model of the head with an electric dipole in it, is proposed for localizing the epileptic focus. From the result of stability test, we find that the gradient project method used for computing an inverse solution of the model has a fast convergence speed. The convergence has very good stability which is not affected by different initial values. Spikes for three patients with different disorders are used for localizing the epileptic discharge sources. For the two patients with lateralized spikes, results from the dipole locations are very similar to the inspections by clinical physicians. However, for the other one with generalized spikes, we fail to localize the discharge source with acceptable accuracy. Thus, we conclude that the electric dipole model with the lateralized spikes is valuable in localizing epileptic discharge sources.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677695

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A three‐level separation scheme applied in the bioassay‐directed search for major airborne mutagenic compounds on inhalable particulate matter has been employed. The biologically “hot” fractions are separated and analyzed chemically or subfractionated to isolate “hot” subfractions which are then chemically analyzed by GC/MS, GC/NCIMS, FTIR, HPLC, Fluorescence and Photodiode Array UV. The mutagenicity assay has involved TA98, TA100, TA98NR and TA98DNP strains. In essence, we are using mutagenicity as our chromatographic detector to pinpoint the most bioactive fractions and compounds in the air which are assumed to be responsible for human health impact, and then identify them as well as assess their reactivity. The comparison of winter and summer samples indicates that the profiles are similar in the two periods. However, levels of polycyclic aromatic hydrocarbons (PAH) are significantly greater in winter as compared to summer. The major mutagenic substances derived from PAH in airborne particulate matter are polar PAH derivatives and the higher contribution of these polar compounds in summer relative to winter suggests that chemical and photochemical reactions during the warm season are important.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677696

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

There are many algorithms reported in the literature to forecast the total real load of a power system. But in a power system, the local area loads (both real and reactive loads) are more helpful for dispatching center operators to schedule generation outputs. An approach to substation load (both real and reactive power) forecast by an artificial neural network (ANN) is presented in this paper Characteristic data of substation load collected continuously by the Supervisory Control and Data Acquisition (SCADA) system of the dispatch center are used for the forecast. The characteristic data include substation historical loads, ambient temperature, relative humidity, system frequency, substation voltages, shunt capacitor status and transformer tap ratios. Since the forecast is based on data acquired by SCADA, the time interval between data samples can be as short as minutes or even seconds; thus, the forecasted load model is suitable for dynamic load studies. Furthermore, the algorithm to vary the number of hidden units is applied to this research and makes it no longer necessary to pre‐determine the number of hidden units. To speed up the training process, an adaptive training process of ANN is also applied. This methodology has been applied to substations in the Taiwan Power Company system to forecast both real and reactive loads and the testing results are satisfactory.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677697

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The methodology of robust control design for reactor/separator modules of plantwide control will be presented. Due to the fact that the recycle causes a significant time delay, the system under consideration contains time delays and state uncertainties which are known only within a given compact bounding form. The proposed method is based on solving the modified algebraic Riccati equation. A sufficient condition which guarantees the robust stability is given as well as an example which satisfactorially demonstrates the capability of this proposed method.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677698

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Steady‐state properties of voltage solutions of distribution systems are attracting more and more attention. In this paper, the voltage stability indicatorLand the optimum impedance approach are employed to investigate the feasibility of voltage solutions. The Jacobian determinant is then developed to analyze the uniqueness of the voltage solutions from a geometrical point of view. The consistency of the above methods is shown. Moreover, it is found that the uniqueness of a voltage solution of a radial distribution system can be proven directly by handling the voltage equation on each bus of the system. The voltage property of a loop system depends on its structure. Three numerical examples are presented.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677699

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Traditionally, to program a distributed memory multiprocessor, a programmer is responsible for partitioning an application program into modules or tasks, scheduling tasks on processors, inserting communication primitives, and generating parallel codes for each processor manually. As both the number of processors and the complexity of problems to be solved increases, programmingdistributed memory multiprocessorsbecomes difficult and error‐prone. In a distributed memory multiprocessor, the program partitioning and scheduling play an important role in the performance of a parallel program. However, how to find the best program partitioning and scheduling so that the best performance of a parallel program on a distributed memory multiprocessor can be achieved, is not an easy task. In this paper, we present a parallel programming tool, PPT, to aid programmers to find the best program partitioning and scheduling and automatically generate the parallel code for thesingle program multiple data(SPMD) model on a distributed memory multiprocessor. An example of designing a parallel FFT program by using PPT on an NCUBE‐2 is also presented.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677700

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Protocol verification is an activity to detect logical errors in communication protocols. In this paper, we propose a hybrid technique for verifying protocols specified in the Extended Communicating Finite State Machine (ECFSM) model. The hybrid technique is achieved as follows: (1) modify the CFSM‐based maximal progress state exploration technique to be ECFSM‐based; (2) incorporate the dead and live variables concept. Our hybrid protocol verification technique is therefore applicable to ECFSM‐based Formal Description Techniques (FDTs), e.g. ISO's Estelle or CCITT's SDL. Based on the hybrid verification technique, an Estelle‐based Hybrid Protocol Verification System (EHPVS) has been developed on SUN SPARC workstations. In this way, protocol designers can use our EHPVS to verify Estelle‐specified protocols.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677701

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In 1993, Wu and Yeh proposed a conference key distribution system based on cross product. In this paper, we will show that Wu and Yeh's system is breakable. We also propose a modified scheme for the conference key distribution system under the same assumption, which can achieve better security.

ISSN:0253-3839    

DOI:10.1080/02533839.1995.9677702

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor