Parallel processing of an object space for image synthesis using ray tracing

This paper presents a novel parallel processing system for image synthesis using ray tracing. An object space is divided into parts (subspaces), each of which is allocated to a processor. The processor detects, simultaneously the intersections of the surfaces of each object and a fixed number of rays over the whole space, and calculates the local intensity on an object in each subspace. The global intensities of pixels on a screen are calculated by the other kind of processors simultaneously. We also present the optimal data structure, based on an adaptive division algorithm, for parallel processing of the object space.     

Low-power 1:16 DEMUX and one-chip CDR with 1:4 DEMUX using InP-InGaAs heterojunction bipolar transistors

Using InP-InGaAs heterojunction bipolar transistor (HBT) technology, we have successfully designed and fabricated a low-power 1:16 demultiplexer (DEMUX) integrated circuit (IC) and one-chip clock and data recovery (CDR) with a 1:4 DEMUX IC for 10-Gb/s optical communications systems. The InP-InGaAs HBTs were fabricated by a nonself-aligned process for high uniformity of device characteristics and producibility. The 1:16 DEMUX IC and the one-chip CDR with the 1:4 DEMUX IC consist of approximately 1200 and 460 transistors, respectively. We have confirmed error-free operation at 10 Gb/s for all data outputs of both ICs. The 1:16 DEMUX IC and the one-chip CDR with the 1:4 DEMUX IC consume only 1 W and 950 mW, respectively. These results demonstrate the feasibility of InP-InGaAs HBTs for low power high-integration optical communication ICs.     

Solving fuzzy shortest path problems by neural networks

In this paper, we introduce the neural networks for solving fuzzy shortest path problems. The penalization of the neural networks is realized after transforming into crisp shortest path model. The procedure and efficiency of this approach are shown with numerical simulations.     

Illuminance dependency of L/Y (lightness/luminance-factor)-ratio effect

Using a modified model for predicting the perceived lightness of chromatic object colors for various adapting illuminances, the following two kinds of predictions were done for seven illuminance levels from 2 to 3000 lx on the basis of the Wysecki data. One concerned the contour lines of equal L/Y (lightness/luminance-factor) ratios in the whole chromaticity gamut, and the other the values of L/Y ratios for spectral colors. All the colors predicted have tristimulus value Y = 20. The computed results confirmed that the difference of L/Y-ratio effect found between the Wysecki and the Sanders-Wyszecki experiment was caused by the difference of the test adapting illuminance between them.     

Cellular array processor CAP and applications

The general-purpose, highly parallel, cellular array processor (CAP) we developed features multiple-instruction stream, multiple-data stream (MIMD) processing and image display. Processor elements can number in several hundreds. The present system uses 256 processors. Each processor element consists of a general-purpose microprocessor, memory, and a special VLSI chip that performs parallel-processing-specific functions such as processor communication and synchronization. The VLSI has two 2M byte/s independent common bus interfaces for data broadcating and six 15M bit/s serial communication ports for local data communication. The chip also can process image data in real time for multiple processors. Use of the communication interfaces enables a variety of processor networks to be configured. One CAP application has been computer graphics, in which ray tracing is used to generate quality images.     

Increase in adhesion molecules on CD4+ cells and CD4+ cell subsets in synovial fluid from patients with rheumatoid arthritis

OBJECTIVE: To elucidate the role of adhesion molecules in the pathogenesis of rheumatoid arthritis (RA). METHODS: We evaluated their expression and that of an activation marker on CD4+ cell populations and CD4+ cell subsets in specimens of peripheral blood (PB) and synovial fluid (SF) obtained from 10 patients with RA and 7 with osteoarthritis (OA). A 2 or 3-color immunofluorescent method was used for analysis. RESULTS: The SF from both groups of patients showed a greater density of adhesion molecules including LFA-1 alpha, LFA-1 beta, CD2, VLA-4 alpha and VLA-5 alpha on CD4+ cells, and a higher percentage of CD4+HLA-DR+ cells compared with their PB. IN PB-CD4+ cell subsets from the arthritic and healthy subjects, the CD4+CD45RO+ cell population showed an increased expression of adhesion molecules compared with CD4+CD45RA+ cell population. The expression of adhesion molecules on circulating CD4+ cell population and CD4+ cell subsets from the patients with RA and OA was comparable to that from healthy subjects. SF from both groups of patients showed a higher percentage of CD4+CD45RO+ cells and a lower percentage of CD4+CD45RA+ cells. In SF-CD4+ cell subsets from patients with RA, the CD4+CD45RO+ cell population had an increased expression of VLA-4 alpha compared to the CD4+CD45RA+ cell population; however, there was no significant difference in other adhesion molecule expression and the percentage of HLA-DR+ cells between the 2 cell subsets. Furthermore, the expression of VLA-4 alpha on the CD4+CD45RO+ cell population in SF from patients with RA was significantly higher than that in matched PB. In CD4+CD45RA+ cell population from both groups of patients, SF showed an enhanced expression of adhesion molecules and an increased percentage of HLA-DR+ cells compared with matched PB. CONCLUSION: Our results suggest that increased expression of adhesion molecules and increased percentage of HLA-DR+ cells on CD4+ cells in SF may be responsible for cellular interactions between these cells and synovial cells or extracellular matrix.     

Synthesis and electrical properties of sodium bismuth niobate Na0.5Bi2.5Nb2O9

The crystal structure of Na_0.5Bi_2.5Nb₂O₉ was refined from its powder X-ray diffraction (XRD) data. Sodium bismuth niobate at 23 °C is orthorhombic, A2₁am, with a=5.4998(3) Å, b=5.4602(2) Å, c=24.952(1) Å, and Z=4. The piezoelectric properties were investigated using the dense bulk ceramics. The electromechanical coupling coefficients (k_ij) and electrical quality factors (Q_m) are k₃₁=3.2%, k_t=10.0%, and Q_m=3800. Single crystals were also grown from stoichiometric melts using a slow cooling technique. The dielectric and ferroelectric properties of the crystal indicates that a spontaneous polarization clearly occurs in the crystallographic a-b plane.     

3.21 ps ECL gate using InP/InGaAs DHBT technology

A new circuit configuration for an emitter-coupled logic (ECL) gate that can reduce propagation delay time has been demonstrated. Nineteen-stage ring oscillators were fabricated using InP/InGaAs double-heterojunction bipolar transistors (DHBTs) with cutoff frequency f/sub T/ and maximum oscillation frequency f/sub max/ of about 232 and 360 GHz, respectively, to evaluate the speed performance of the proposed ECL gate. The minimum propagation delay is 3.21 ps/gate. The proposed ECL gate is about 8% faster than the conventional ECL gate.     

Appearance of fosfomycin resistant Rahnella aquatilis clinically isolated in Japan

Among recent clinical isolates in Japan, strain CU264 was discovered which formed unusual colonies. This strain was identified as Rahnella aquatilis which is usually found in water. The antibiotic susceptibilities against tetracycline, carbenicillin, chloramphenicol, streptomycin, kanamycin, gentamicin, sulphonamide, neomycin, fosfomycin, rifampicin, norfloxacin and nalidixic acid, were investigated. The result demonstrated that the strain was highly resistant to fosfomycin only. It was further shown that this resistance was transmissible with low frequency to Serratia marcescens whereas it was not transmissible to Escherichia coli.