A VLSI architecture for a half-edge-based corner detector

Corner detection is a low-level feature detection operator that is of great use in image processing applications, for example, optical flow and structure from motion by image correspondence. The detection of corners is a computationally intensive operation. Past implementations of corner detection techniques have been restricted to software. In this paper we propose an efficient very large-scale integration (VLSI) architecture for detection of corners in images. The corner detection technique is based on the half-edge concept and the first directional derivative of Gaussian. Apart from the location of the corner points, the algorithm also computes the corner orientation and the corner angle and outputs the edge map of the image. The symmetrical properties of the masks are utilized to reduce the number of convolutions effectively, from eight to two. Therefore, the number of multiplications required per pixel is reduced from 1800 to 392. Thus, the proposed architecture yields a speed-up factor of 4.6 over conventional convolution architectures. The architecture uses the principles of pipelining and parallelism and can be implemented in VLSI.     

A personal computer based system used in electromyography for interpretation and reporting

Programs for rule based electromyography (EMG) interpretation and reporting are described. A number of parameters are obtained during an EMG investigation. The combination of these data leads to a neurophysiological conclusion. Knowledge from the literature, research and experience is the basis for rule development. Rules have been developed for 14 of the most commonly used classifications of an EMG. The syntax is relatively easy and the user may change the rules, add rules or apply the system for other types of data. The results are displayed in a new graphical way. The system presented here is part of an integrated EMG laboratory with administrative routines, distributed databases for storage of results and routines for automatic report generation.     

Single-Phase Permanent-Magnet Motor Analysis

A unified theoretical approach is presented for the calculation of the performance of the single-phase capacitor-start permanent-magnet (PM) ac line-start motor. The earlier work of Chang and of Finch and Lawrenson on capacitor reluctance motors is extended. As far as possible, a common set of reference frame transformations for steady-state, transient, and asynchronous performance is also provided, permitting the use of all the theory developed for the analysis of the balanced polyphase PM motor. A new approximate technique is given for estimating the average asynchronous torque/speed curve from computed acceleration curves.     

Investigation of the impact of changes in demand forecasting method on the financial performance of an electricity supply undertaking

Peak demand forecasts obtained from six different univariate forecasting methods, under a range of conditions, were used to drive a capacity acquisition model of a large electrical supply system; and the resulting physical and financial performance of the model was observed for each set of forecasts. The results obtained are discussed in the context of their implications for the choice of load forecasting method used in capacity acquisition planning by a power supply undertaking.     

High-gain pseudomorphic InGaAs base ballistic hot-electron device

A high-gain ballistic hot-electron device is described. The GaAs-AlGaAs heterostructure device, with a 21-mm-thick pseudomorphic In _0.12Ga_0.88As base, had a current gain of 27 at 77 K and 41 at 4.2 K. As characteristically seen in ballistic devices, transfer into the L valley limited the maximum gain. The Γ-L valley separation in the strained In_0.12Ga_0.88As was estimated to be about 380 meV     

Phase relations in the ternary system Cu-In-Se

The phase relations of the ternary system Cu-In-Se were studied at 750° C by quenching experiments. Special attention was given to the region CuInSe₂In₂Se₃-In₄Se₃. Only four ternary phases with extended homogeneity ranges were found to exist. They were characterized by X-ray powder diffraction, electron microprobe analysis (EK8PA)' end optical microscopy. Differential thermal analysis (DTA) investigations allowed us to construct theT-x diagram of the Cu₂Se-In₂Se₃. out between 47 and 100 mol% In₂Se₃. Besides, it was also possible to give a tentative diagram of the solid-liquid equilibria at 750° C and to get some information on the sub-solid existence fields beside the Cu₂Se-In₂Se₃ cut.     

Physical modeling of gas/liquid mass transfer in a gas stirred ladle

The absorption of gas through the plume eye and of an injected gas in a steelmaking ladle process was investigated, using a physical model of CO₂ absorption into a NaOH solution. The results show that the inert gas escaping through the plume eye is ineffective in protecting the bath from the atmosphere, and placing an oil layer (simulated slag) decreases the absorption rate significantly. Increasing the flow rate of the inert gas not only exposes more of the liquid surface to the CO₂ atmosphere, but also increases the mass transfer coefficient at the surface. The overall mass transfer between an injected CO₂ gas and NaOH solution includes the mass transfer through the surface of the bath as well as the mass transfer in the bubble dispersion zone. The difference between the mass transfer in the bubble dispersion zone and the overall mass transfer was found to be significant for relatively low gas flow rates. The mass transfer coefficient of CO₂ in the bubble dispersion zone was estimated using available information regarding the bubble size and velocity. Mass transfer coefficient estimated for the constant bubble frequency regime shows a dependence on gas flow rate. However, if a constant characteristic size of bubbles is assumed as an alternative approach, the mass transfer coefficient is independent of the gas flow rate.     

Pulse stabilisation in harmonically FM modelocked erbium fibre ring laser with DFBLD

A new pulse stabilisation scheme for a harmonically frequency modulated (FM) modelocked erbium fibre ring laser using a distributed feedback laser diode (DFBLD) is presented. More than 65 dB supermode noise suppression in the RF spectrum was obtained with the proposed method. Effective reduction of supermode noise can be accomplished as the DFBLD in the fibre laser acts not only as a fast-gain saturated medium but also as an optical bandpass filter for suppressing supermode noise in a harmonically modelocked laser system.     

Design and fabrication of RESURF MOSFETs on 4H-SiC(0001), (112~0), and 6H-SiC(0001)

Design and fabrication of lateral SiC reduced surface field (RESURF) MOSFETs have been investigated. The doping concentration (dose) of the RESURF and lightly doped drain regions has been optimized to reduce the electric field crowding at the drain edge or in the gate oxide by using device simulation. The optimum oxidation condition depends on the polytype: N/sub 2/O oxidation at 1300/spl deg/C seems to be suitable for 4H-SiC, and dry O/sub 2/ oxidation at 1250/spl deg/C for 6H-SiC. The average inversion-channel mobility is 22, 78, and 68 cm/sup 2//Vs for 4H-SiC(0001), (112~0), and 6H-SiC(0001) MOSFETs, respectively. RESURF MOSFETs have been fabricated on 10-/spl mu/m-thick p-type 4H-SiC(0001), (112~0), and 6H-SiC(0001) epilayers with an acceptor concentration of 1/spl times/10/sup 16/ cm/sup -3/. A 6H-SiC(0001) RESURF MOSFET with a 3-/spl mu/m channel length exhibits a high breakdown voltage of 1620 V and an on-resistance of 234 m/spl Omega//spl middot/cm/sup 2/. A 4H-SiC(112~0) RESURF MOSFET shows the characteristics of 1230 V-138 m/spl Omega//spl middot/cm/sup 2/.     

Simulation of the initial stages of nucleation and growth of Au/NaCl(100)

The results of a computer simulation of the initial stages of the nucleation and growth of gold on NaCl(100) are presented. A potential energy scaling Monte Carlo model employing a 50 × 50 array, mobile monomers, dimers and trimers, and gold atom vertical “roll up” was used. The parameters in the model were obtained from the work of Robinson and Robins, other published sources and/or found by calculation. Simulations of the migration of single gold adatoms over the surface permitted the determination of the diffusion coefficient as a function of the reciprocal temperature which returned the same activation energy given by the potential field, thus indicating the consistency of the model. Initial cluster densities were determined using deposition rates of R_d = 10¹⁵cm^-2s^-1 and R_d = 10¹⁴cm^-2s^-1 over the temperature range T=200–425 K. Initial cluster growth was found to occur primarily by surface phase transport and resulted in clusters that were shaped like very thin disks. Using the equations from the work of Velfe and coworkers, calculations were made to extrapolate the computer simulation data in order to permit an indirect comparison with the data of Robinson and Robins. Good agreement was achieved. Initial condensation coefficients determined over a 250 ms interval showed that α ≈ 0 at T > 425 K and α ≈ 1 at T < 325 K for a deposition rate of R_d=10¹⁵ cm^-2 s^-1.