A CMOS integrated circuit for multichannel multiple-subjectbiotelemetry using bidirectional optical transmissions [weightlessnessin space effects application]

A CMOS integrated circuit for a noninvasive biological-signal telemetry system specified for use in medical and physiological studies of the influence of weightlessness in space is presented. The system can monitor multichannel (4 channels maximum) biological signals from multiple subjects (4 subjects maximum) in real time by using time multiplexing. A key technique so-called synchronized multiple-subject telemetry, to achieve multiple-subject telemetry has been proposed. This technique utilizes bidirectional optical transmissions with direct and scattered infrared lights between an observer and each of the subjects. An experimental CMOS IC to give a small light-weight low-power, and smart telemetry instrument for use on animals has been developed. This IC is for evaluating circuit blocks of the implantable monolithic telemetry instrument. The major circuit blocks include CMOS digital circuits for synchronization, subject selection and time multiplexing, analog circuits for pulse interval modulation, and other blocks such as a CMOS optical pulse receiver and an LED driver. A preliminary experimental multichannel telemetry from two subjects has been performed with the implemented IC chips, and the principal operation of the multiple-subject optical biotelemetry has been demonstrated     

Structures and electronic properties of surface/edges of nanodiamond and nanographite

The structure, electronic and magnetic properties of nanodiamond and nanographite/nanographene are investigated. Detonation nanodiamond particles that are covered with amorphous graphitic composites are hydrothermally treated to remove the graphitic surface composites and to terminate the surface carbon atoms with hydrogen. The number of localized spins of dangling bonds and the hydrogen concentration increase upon the increase in the hydrothermal treatment time up to 40 h. Above 40 h, both drop discontinuously, a surface structural reconstruction was suggested. The creation of dangling bonds and an incomplete hydrogenation of the surface carbon atoms destabilize the surface, resulting in the structural reconstruction. Nanodiamond particles are thermally converted to nanographite/nanographene. A single nanographene sheet is successfully prepared by heat-treating nanodiamond particles. The edge of graphene sheet with its edge carbon atoms being hydrogen-terminated is investigated by UHV-STM/STS. Zigzag edges are found to have non-bonding π-state of edge origin, in good agreement with theoretical prediction.     

Transmission of correct gaze direction in video conferencing using screen-embedded cameras

In this paper, we propose a new video conferencing system that presents correct gaze directions of a remote user by switching among images obtained from multiple cameras embedded in a screen according to a local user’s position. Our proposed method reproduces a situation like that in which the remote user is in the same space as the local user. The position of the remote user to be displayed on the screen is determined so that the positional relationship between the users is reproduced. The system selects one of the embedded cameras whose viewing direction towards the remote user is the closest to the local user’s viewing direction to the remote user’s image on the screen. As a result of quantitative evaluation, we confirmed that, in comparison with the case using a single camera, the accuracy of gaze estimation was improved by switching among the cameras according to the position of the local user.

     

Partial redundancy elimination for access expressions by speculative code motion

We present a new memory access optimization for Java to perform aggressive code motion for speculatively optimizing memory accesses by applying partial redundancy elimination (PRE) techniques. First, to reduce as many barriers as possible and to enhance code motion, we perform alias analysis to identify all the regions in which each object reference is not aliased. Secondly, we find all the possible barriers. Finally, we perform code motions in three steps. For the first step, we apply a non‐speculative PRE algorithm to move load instructions and their following instructions in the backwards direction of the control flow graph. For the second step, we apply a speculative PRE algorithm to move some of them aggressively before the conditional branches. For the third step, we apply our modified version of a non‐speculative PRE algorithm to move store instructions in the forward direction of the control flow graph and to even move some of them after the merge points. We implemented our new algorithm in our production‐level Java just‐in‐time compiler. Our experimental results show that our speculative algorithm improves the average (maximum) performance by 13.1% (90.7%) for jBYTEmark and 1.4% (4.4%) for SPECjvm98 over the fastest algorithm previously described, while it increases the average (maximum) compilation time by 0.9% (2.9%) for both benchmark suites. Copyright © 2004 John Wiley & Sons, Ltd.     

Correlations of Hepatic Hemodynamics,Liver Function,and Fibrosis Markers in Nonalcoholic Fatty Liver Disease: Comparison with Chronic Hepatitis Related to Hepatitis C Virus

The progression of chronic liver disease differs by etiology. The aim of this study was to elucidate the difference in disease progression between chronic hepatitis C (CHC) and nonalcoholic fatty liver disease (NAFLD) by means of fibrosis markers, liver function, and hepatic tissue blood flow (TBF). Xenon computed tomography (Xe-CT) was performed in 139 patients with NAFLD and 152 patients with CHC (including liver cirrhosis (LC)). The cutoff values for fibrosis markers were compared between NAFLD and CHC, and correlations between hepatic TBF and liver function tests were examined at each fibrosis stage. The cutoff values for detection of the advanced fibrosis stage were lower in NAFLD than in CHC. Although portal venous TBF (PVTBF) correlated with liver function tests, PVTBF in initial LC caused by nonalcoholic steatohepatitis (NASH-LC) was significantly lower than that in hepatitis C virus (C-LC) (p = 0.014). Conversely, the liver function tests in NASH-LC were higher than those in C-LC (p < 0.05). It is important to recognize the difference between NAFLD and CHC. We concluded that changes in hepatic blood flow occurred during the earliest stage of hepatic fibrosis in patients with NAFLD; therefore, patients with NAFLD need to be followed carefully.     

A 32×32-bit multiplier using multiple-valued MOS current-modecircuits

A 32×32-bit multiplier using multiple-valued current-mode circuits has been fabricated in 2-μm CMOS technology. For the multiplier based on the radix-4 signed-digit number system, 32×32-bit two's complement multiplication can be performed with only three-stage signed-digit full adders using a binary-tree addition scheme. The chip contains about 23600 transistors and the effective multiplier size is about 3.2×5.2 mm², which is half that of the corresponding binary CMOS multiplier. The multiply time is less than 59 ns. The performance is considered comparable to that of the fastest binary multiplier reported     

A High-Speed, High-Sensitivity Digital CMOS Image Sensor With a Global Shutter and 12-bit Column-Parallel Cyclic A/D Converters

This paper presents a high-speed, high-sensitivity 512times512 CMOS image sensor with column parallel cyclic 12-bit ADCs and a global electronic shutter. Each pixel has a charge amplifier for high charge-to-voltage conversion gain despite of using a large-size photodiode, and two sample-and-hold stages for the global shutter and fixed pattern noise (FPN) canceling. High-speed column-parallel cyclic ADC arrays with 12-bit resolution having a small layout size of 0.09 mm ² are integrated at both sides of image array. A technique for accelerating the conversion speed using variable clocking and sampling capacitance is developed. A digital gain control function using 14-bit temporal digital code is also set in the column parallel ADC. The fabricated chip in 0.25-mum CMOS image sensor technology achieves the full frame rate in excess of 3500 frames/s. The in-pixel charge amplifier achieves the optical sensitivity of 19.9 V/lxmiddots. The signal full scale at the pixel output is 1.8 V at 3.3-V supply and the noise level is measured to be 1.8mV_rms, and the resulting signal dynamic range is 60 dB     

A Low-Power Low-Voltage 10-bit 100-MSample/s Pipeline A/D Converter Using Capacitance Coupling Techniques

This paper presents a low-power low-voltage 10-bit 100-MSample/s pipeline analog-to-digital converter (ADC) using capacitance coupling techniques. A capacitance coupling sample-and-hold stage achieves high SFDR with 1.0-V supply voltage at a high sampling rate. A capacitance coupling folded-cascode amplifier effectively saves the power consumption of the gain stages of the ADC in a 90-nm digital CMOS technology. The SNDR and the SFDR are 55.3 dB and 71.5 dB, respectively, and the power consumption is 33 mW     

Analogue MOS current-mode circuits for three-dimensional integrated smart image sensor

An image processing technique using analogue MOS current-mode circuits is presented. This approach is of interest in smart image sensors based on three-dimensional (or multi-layered) VLSI structures. High-performance smart image sensors with high resolution can be realised because the number of transistors required for image processing in each pixel is greatly reduced.<>