A channel-erasing 1.8-V-only 32-Mb NOR flash EEPROM with a bitlinedirect sensing scheme

A 1.8-V-only 32-Mb NOR flash EEPROM has been developed based on the 0.25-μm triple-well double-metal CMOS process. A channel-erasing scheme has been implemented to realize a cell size of 0.49 μm² , the smallest yet reported for 0.25-μm CMOS technology. A block decoder circuit with a novel erase-reset sequence has been designed for the channel-erasing operation. A bitline direct sensing scheme and a wordline boosted voltage pooling method have been developed to obtain high-speed reading operation at low voltage. An access time of 90 ns at 1.8 V has been realized     

Adaptive MLP post-processing for block-based coded images

Block-based image coding techniques are widely used for encoding images and videos. However, many annoying artefacts appear when an image is encoded at low bit rates. In these artefacts, the blocking effects are very obvious to human vision. Thus, an efficient blocking effect reduction scheme is essential for preserving the visual quality of decompressed images. A new adaptive post-processing algorithm is proposed to reduce the blocking artefacts of block-based coded images by using neural network techniques in the spatial domain. The algorithm combines a variance-based classifier and multilayer perceptrons to improve the performance of post-processing. In the proposed algorithm, the blocking and ringing effects in a reconstructed image are diminished without blurring of the edges, and the detailed region in the image is also enhanced. Comparison results between the proposed algorithm and other algorithms are made with several Joint Photographic Experts Group and vector quantisation decompressed images. In the simulations, the results of reconstructed images with improvements in both visual quality and PSNR are shown. It is found that the proposed algorithm is an effective post-processing algorithm for block-based image coding at low bit rates     

Controlled levitation of bulk superconductors

Levitation of bulk Y-Ba-Cu-O superconductors could successfully be controlled using a Bi-Sr-Ca-Cu-O superconducting electromagnet. It was found that stable levitation without tilting was obtained only when the sample trapped a certain amount of field, the minimum of which depended on the external field and the sample dimensions. We also employed a novel analysis method for levitation based on the total energy balance, which is much simpler than the force method and could be applied to the understanding of general levitation behavior. Numerical analyzes thus developed suggested that stable levitation of superconductors with large dimensions can only be achieved when the induced currents can flow with three dimensional freedom     

Cell planning with capacity expansion in mobile communications: atabu search approach

The cell planning problem with capacity expansion is examined in wireless communications. The problem decides the location and capacity of each new base station to cover expanded and increased traffic demand. The objective is to minimize the cost of new base stations. The coverage by the new and existing base stations is constrained to satisfy a proper portion of traffic demands. The received signal power at the base station also has to meet the receiver sensitivity. The cell planning is formulated as an integer linear programming problem and solved by a tabu search algorithm. In the tabu search intensification by add and drop move is implemented by short-term memory embodied by two tabu lists. Diversification is designed to investigate proper capacities of new base stations and to restart the tabu search from new base station locations. Computational results show that the proposed tabu search is highly effective. A 10% cost reduction is obtained by the diversification strategies. The gap from the optimal solutions is approximately 1~5% in problems that can be handled in appropriate time limits. The proposed tabu search also outperforms the parallel genetic algorithm. The cost reduction by the tabu search approaches 10~20% in problems: with 2500 traffic demand areas (TDAs) in code division multiple access (CDMA)     

Laser Diode Pumping High-stability 1047 nm TEM00 Mode CW Nd:YLiF4 Laser

A laser diode (LD) pumping high-stability 1047 nm TEM00 mode Nd: YLiF4 (Nd: YLF) continuous wave (CW) laser is reported in this letter. The laser output power of 5.83 W with optical to optical effidency of 27％ and slope efficiency of 30％ has been achieved The instability of output power is 0.36％ and spike caused by relaxation oscillation has not been observed in the laser beam. The transverse cross section of laser beam is an ellipse, the diameters of laser beam at output mirror in both directions are 0.97 mm and 1.07 mm, respectively. The divergent angles are 0. 936 mrad and 0. 774 mrad, and the values of M2 are 1.37 and 1.24, respectively. The polarization degree of laser beam is better than 237:1.     

Testing the Local Interconnect Resources of SRAM-Based FPGA's

This paper addresses the problem of testing the configurable modules used in the local interconnect of SRAM-based FPGAs. First, it is demonstrated that a n address bit Configurable Interface Multiplexer requires N = 2 ⁿ test configurations considering a stuck-at as well as a functional fault model. Second, a logic cell with a set of k input Configurable Interface Modules with n address bits is analyzed and it is proven that the set of CIMs can be tested in parallel making the number of required test configurations equal to N = 2 ⁿ . Third, it is shown that the complete circuit i.e. a m × m array of sets of k Configurable Interface Multiplexers with n address bits can be tested with only N = 2 ⁿ test configurations using the XOR tree and shift register structures.     

A 640 by 480 Pixels Readout Circuit for IR Imaging

A readout circuit for a 640 × 480 pixels FPA (focal plane array) has been successfully designed, fabricated and tested. The circuit solution is based on a per pixel source-follower direct injection (SFDI) pre-amplifier. Signal multiplexing is performed in both X and Y direction. The pixel size is 25 m × 25m. The chip is optimized for a QWIP (quantum well infrared photodetector) operating at a temperature of 70 K. The circuit has been realized in a standard 0.8 m CMOS process.     

Correction of MR kappa-space data corrupted by spike noise

Magnetic resonance images are reconstructed from digitized raw data, which are collected in the spatial-frequency domain (also called kappa-space). Occasionally, single or multiple data points in the k-space data are corrupted by spike noise, causing striation artifacts in images. Thresholding methods for detecting corrupted data points can fail because of small alterations, especially for data points in the low spatial frequency area where the k-space variation is large. Restoration of corrupted data points using interpolations of neighboring pixels can give incorrect results. We propose a Fourier transform method for detecting and restoring corrupted data points using a window filter derived from the striation-artifact structure in an image or an intermediate domain. The method provides an analytical solution for the alteration at each corrupted data point. It can effectively restore corrupted kappa-space data, removing striation artifacts in images, provided that the following three conditions are satisfied. First, a region of known signal distribution (for example, air background) is visible in either the image or the intermediate domain so that it can be selected using a window filter. Second, multiple spikes are separated by the full-width at half-maximum of the point spread function for the window filter. Third, the magnitude of a spike is larger than the minimum detectable value determined by the window filter and the standard deviation of kappa-space random noise.     

Morphology-based three-dimensional interpolation

In many medical applications, the number of available two-dimensional (2-D) images is always insufficient. Therefore, the three-dimensional (3-D) reconstruction must be accomplished by appropriate interpolation methods to fill gaps between available image slices. In this paper, we propose a morphology-based algorithm to interpolate the missing data. The proposed algorithm consists of several steps. First, the object or hole contours are extracted using conventional image-processing techniques. Second, the object or hole matching issue is evaluated. Prior to interpolation, the centroids of the objects are aligned. Next, we employ a dilation operator to transform digital images into distance maps and we correct the distance maps if required. Finally, we utilize an erosion operator to accomplish the interpolation. Furthermore, if multiple objects or holes are interpolated, we blend them together to complete the algorithm. We experimentally evaluate the proposed method against various synthesized cases reported in the literature. Experimental results show that the proposed method is able to handle general object interpolation effectively.     

Flat panel detector-based cone-beam volume CT angiography imaging: system evaluation

Preliminary evaluation of recently developed large-area flat panel detectors (FPDs) indicates that FPDs have some potential advantages: compactness, absence of geometric distortion and veiling glare with the benefits of high resolution, high detective quantum efficiency (DQE), high frame rate and high dynamic range, small image lag (< 1%), and excellent linearity (approximately 1%). The advantages of the new FPD make it a promising candidate for cone-beam volume computed tomography (CT) angiography (CBVCTA) imaging. The purpose of this study is to characterize a prototype FPD-based imaging system for CBVCTA applications. A prototype FPD-based CBVCTA imaging system has been designed and constructed around a modified GE 8800 CT scanner. This system is evaluated for a CBVCTA imaging task in the head and neck using four phantoms and a frozen rat. The system is first characterized in terms of linearity and dynamic range of the detector. Then, the optimal selection of kVps for CBVCTA is determined and the effect of image lag and scatter on the image quality of the CBVCTA system is evaluated. Next, low-contrast resolution and high-contrast spatial resolution are measured. Finally, the example reconstruction images of a frozen rat are presented. The results indicate that the FPD-based CBVCT can achieve 2.75-lp/mm spatial resolution at 0% modulation transfer function (MTF) and provide more than enough low-contrast resolution for intravenous CBVCTA imaging in the head and neck with clinically acceptable entrance exposure level. The results also suggest that to use an FPD for large cone-angle applications, such as body angiography, further investigations are required.