A body-shadowing model for indoor radio communication environments

Deterministic propagation prediction methods proposed for indoor radio are useful for estimating the average propagation loss in real environments, which usually have complicated geometries. On the other hand, these methods generally fail to accommodate human body shadowing, which is a significant propagation effect in indoor picocells. Several empirical models to describe body shadowing have been reported. However, to our knowledge, no appropriate model that can be used in combination with deterministic propagation prediction methods has been provided in the literature. In this paper, a new practical model is introduced, which provides a way to estimate body-shadowing effects deterministically with the existing ray-determination methods. The detailed procedure to combine our body-shadowing model with the ray-determination methods is described. Several examples are shown applying the procedure to a simple office layout     

Multiobjective evolutionary computation for supersonic wing-shapeoptimization

This paper discusses the design optimization of a wing for supersonic transport (SST) using a multiple-objective genetic algorithm (MOGA). Three objective functions are used to minimize the drag for supersonic cruise, the drag for transonic cruise, and the bending moment at the wing root for supersonic cruise. The wing shape is defined by 66 design variables. A Euler flow code is used to evaluate supersonic performance, and a potential flow code is used to evaluate transonic performance. To reduce the total computational time, flow calculations are parallelized on an NEC SX-4 computer using 32 processing elements. The detailed analysis of the resulting Pareto front suggests a renewed interest in the arrow wing planform for the supersonic wing     

Thermal Spray Using a High-Frequency Pulse Detonation Combustor Operated in the Liquid-Purge Mode

Experiments on thermal spray by pulsed detonations at 150 Hz were conducted. Two types of pulse detonation combustors were used, one operated in the inert gas purge (GAP) mode and the other in the liquid-purge (LIP) mode. In both modes, all gases were supplied in the valveless mode. The GAP mode is free of moving components, although the explosive mixture is unavoidably diluted with the inert gas used for the purge of the hot burned gas. In the LIP mode, pure fuel-oxygen combustion can be realized, although a liquid-droplet injector must be actuated cyclically. The objective of this work was to demonstrate a higher spraying temperature in the LIP mode. First, the temperature of CoNiCrAlY particles heated by pulsed detonations was measured. As a result, the spraying temperature in the LIP mode was higher than that in the GAP mode by about 1000 K. Second, the temperature of yttria-stabilized zirconia (YSZ) particles, whose melting point was almost 2800 °C, heated by pulsed detonations in the LIP mode was measured. As a result, the YSZ particles were heated up to about 2500 °C. Finally, a thermal spray experiment using YSZ particles was conducted, and a coating with low porosity was successfully deposited.     

Perovskite-type compounds as electrode catalysts for cathodic reduction of oxygen

The perovskite-type compounds (Ln, M)M′O₃ (Ln: lanthanoid, M: alkaline earth, M′: transition metal) are synthesized, and the related perovskite formation region is determined. The resistivities of these compounds at 25°C decrease by several orders of magnitude when they are doped with Ca, Sr or Ba. The resistivity minima range from 10^?4 to 10^?1 Ωcm, depending on the composition. The oxygen ion diffusion constants are evaluated from the electrode potentials in a KOH solution. The diffusion constant for Nd_0.8Sr_0.2 CoO₃ is 1.4 × 10^?11 cm²/s at 25°C. These compounds are examined as potential oxygen electrode materials for alkaline solution metal fuel cells, and (Nd, Sr)CoO₃ provides good performance for several hundred hours.     

A dynamic associative memory system by adopting an amygdala model

Although several kinds of computational associative memory models and emotion models have been proposed since the last century, the interaction between memory and emotion is almost always neglected in these conventional models. This study constructs a dynamic memory system, named the amygdala-hippocampus model, which intends to realize dynamic auto-association and the mutual association of time-series patterns more naturally by adopting an emotional factor, i.e., the functional model of the amygdala given by Morén and Balkenius. The output of the amygdala is designed to control the recollection state of multiple chaotic neural networks (MCNN) in CA3 of the hippocampus-neocortex model proposed in our early work. The efficiency of the proposed association system is verified by computer simulation using several benchmark time-series patterns. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

L-Ergothioneine scavenges superoxide and singlet oxygen and suppresses TNF-α and MMP-1 expression in UV-irradiated human dermal fibroblasts

The hair lipid composition collected from 44 Japanese females between 1 and 81 years of age was examined for eight lipids including hydrocarbons (HCs), squalene (SQ), wax esters (WEs), triglycerides (TGs), fatty acids (FAs), cholesterol (CH), ceramides (CERs), and 18-methyl eicosanoic acid (MEA). In this study, the 5-cm length from the proximal root end of hair fibers, which had never been exposed to any chemical treatment, was used after 5-min incubation with hexane following shampooing. Hair lipids were extracted with solvent and subsequent alkali-solvent and were then analyzed by a combination of chromatography. Although the average contents of the lipids showed great fluctuations among individuals, there were significant correlations between the levels of each lipid, which allowed for the classification of the hair lipids into four groups: group A: SQ, WEs, TGs, and FAs (designated as endogenous lipids based upon their sebum origin); group B: CH and CERs (designated as endogenous lipids); group C: HC (unknown origin); and group D: MEA (the other endogenous lipid). A principal component analysis for eight lipids revealed that the hair lipid composition was characterized by a predominant negative correlation between each lipid for groups A and B. This negative correlation suggests that the endogenous lipids in group B serve as a barrier against the penetration of predominantly sebum-derived exogenous lipids (group A). Endogenous lipids consisting of CH and CERs (group B) and MEA (group D) should be designated as intrinsic internal lipids of human hair.     

Intelligent agent construction using the attentive characteristic patterns of chaotic neural networks

Humans learn from incidents in their own life and reflects these in subsequent actions as their own experiences. These experiences are memorized in the brain and recollected when necessary. This research incorporates this type of intelligent information processing mechanism and applies it to an autonomous agent. In the proposed system, the reinforcement Q-learning method is used. Autoassociative chaotic neural networks are also used as mutual associative memory systems. However, an agent cannot retrieve all stored patterns exactly, especially in the case of too many stored patterns and a strong correlation among them. To solve this problem, we propose to use types of attentive parameters and attentive characteristic patterns. The attentive characteristic pattern is part of the stored patterns. When robots concentrate their attention on a specific part of a stored pattern, i.e., the attentive characteristic pattern, whole stored patterns are retrieved easily and completely. Finally, the effectiveness of the proposed method is verified through a simulation applied to plural maze-searching problems.     

Synthesis of TiB2 powder from a mixture of TiN and amorphous boron

TiB₂ powder was synthesized by solid state reaction using amorphous boron and TiN as a source of titanium. The TiB₂ formation did not occur at all in a nitrogen atmosphere even at 1400° C. TiB₂ formed above 1100° C in argon and hydrogen atmospheres. The only crystalline phase of TiB₂ powder was favourably synthesized at 1400° C for 360 min in an argon atmosphere from a starting powder with a composition containing excess boron (B/Ti = 2.2). The synthesized powder was well dispersed and had a particle size of 0.5 to 2 µm. The powder activity was evaluated by sintering at 4 G Pa and 1300 to 1600° C for 15 min.     

Shorter-wavelength lithography utilizing MRS-type negative resists

New negative photoresists, called MRS-type resists, are successfully applied to deep-UV 1:1 projection printing and 365 nm 10:1 reduction projection printing. The MRS-type resists are characterized by intense absorption of exposure light and absence of swelling in aqueous developer solutions. They resolve steep profile submicron images in a 1.0 μ thick film. They are not adversely affected by reflected light from water surfaces. In order to use MRS-type resists with broader development latitude, optimizing the extent of light absorption is important because the resist profiles strongly depend on development conditions due to increasing solubility towards the resist bottom.     

Cardiovascular effects of ajmaline

Ajmaline, a rauwolfia derivative, has been found to possess potent antiarrhythmic effects. The present study has been designed to define the cardiovascular effects of this drug. Hemodynamic studies performed in anesthetized and conscious dogs demonstrated no significant changes in measured hemodynamic parameters at doses equal to or less than 2 mg. per kilogram. Studies in isolated papillary muscle demonstrated no negative inotropic effects until concentrations of 1 X 10(-4). Disparate results were obtained with regard to heart rate reflecting the state of autonomic tone. Electrophysiologic studies in both anesthetized and conscious dogs demonstrated a significant depression of intraventricular conduction with no significant effect on AV nodal conduction; ventricular automaticity was not affected. Ajmaline did not alter digitalis-induced AV nodal conduction prolongation. However, ajmaline dramatically altered or abolished ventricular arrhythmias secondary to acute ischemia. In conclusion, these studies demonstrate that ajmaline specifically depresses intraventricular conduction, suggesting that this drug would be particularly effective in the treatment of re-entrant ventricular arrhythmias.