Showing papers by "Tokyo Institute of Technology published in 1985"

Fuzzy identification of systems and its applications to modeling and control

Abstract: A mathematical tool to build a fuzzy model of a system where fuzzy implications and reasoning are used is presented. The premise of an implication is the description of fuzzy subspace of inputs and its consequence is a linear input-output relation. The method of identification of a system using its input-output data is then shown. Two applications of the method to industrial processes are also discussed: a water cleaning process and a converter in a steel-making process.

A radial line slot antenna for 12 GHz satellite TV reception

Abstract: The analysis and design of novel planar antennas which can radiate circularly polarized pencil beams in x -band are presented for the application of receiving direct broadcast from a satellite (DBS). This antenna belongs to a class of slotted waveguide antennas and high efficiency is expected in principle. A circular two-dimensional aperture is located on the top plate of a twofold radial waveguide and is excited by a radially inward traveling transverse electromagnetic (TEM) mode in the upper waveguide. Slots are arrayed on the aperture spirally in such a way that they can couple with the radial currents flowing over the aperture plate to produce a circularly polarized broadside beam. Promising performances of the antenna are predicted theoretically. Experiments are performed with respect to basic characteristics of the antenna and they show the validity of the design and analysis.

Density-matrix theory of semiconductor lasers with relaxation broadening model - Gain and gain-suppression in semiconductor lasers

Abstract: The density-matrix theory of semiconductor lasers with relaxation broadening model is finally established by introducing theoretical dipole moment into previously developed treatments. The dipole moment is given theoretically by the k . p method and is calculated for various semiconductor materials. As a result, gain and gain-suppression for a variety of crystals covering wide wavelength region are calculated. It is found that the linear gain is larger for longer wavelength lasers and that the gain-suppression is much larger for longer wavelength lasers, which results in that single-mode operation is more stable in long-wavelength lasers than in shorter-wavelength lasers, in good agreement with the experiments.

Density-matrix theory of semiconductor lasers with relaxation broadening model-gain and gain-suppression in semiconductor lasers

Abstract: The density-matrix theory of semiconductor lasers with relaxation broadening model is finally established by introducing theoretical dipole moment into previously developed treatments. The dipole moment is given theoretically by the k . p method and is calculated for various semiconductor materials. As a result, gain and gain-suppression for a variety of crystals covering wide wavelength region are calculated. It is found that the linear gain is larger for longer wavelength lasers and that the gain-suppression is much larger for longer wavelength lasers, which results in that single-mode operation is more stable in long-wavelength lasers than in shorter-wavelength lasers, in good agreement with the experiments.

Anodic Oxidation of Reductants in Electroless Plating

Abstract: The anodic oxidation of reductants (hypophosphite, formaldehyde, borohydride, dimethylamine borane, and hydrazine) was studied on different metal electrodes (Au, Pt, Pd, Ag, Cu, Ni, and Co) at various temperatures, with special interest in the catalytic aspect of electroless plating. The rate of the anodic oxidation strongly depended on the pH value, the concentration of reductants, and the nature of the metal electrode. The catalytic activities of the metals for the anodic oxidation of different reductants were evaluated by the potentials at a reference current density. The order of the catalytic activity with metal varied depending on the nature of the reductants. The catalytic activity series thus obtained can be utilized for choosing the reductant suitable for the metal to be deposited. Arrhenius plots of the anodic currents on different metals at a reference potential yielded their respective straight lines. Some correlations were observed between the catalytic activity and the activation energy. The catalytic activity series was discussed in connection with that for hydrogen electrode reaction.

A model of human evaluation process using fuzzy measure

Abstract: This paper presents a mathematical model for the human subjective evaluation process using fuzzy integrals based on the general fuzzy measure. First, the concept of overlap coefficient is introduced to describe the properties of a given fuzzy measure and to characterize the human evaluation process. Further, a new algorithm is developed to identify the fuzzy measure with full degrees of freedom. Lastly, the model and the identification scheme are applied to two practical examples: prediction of wood strength by an experienced inspector and trouble evasive actions taken by a computer game player.

Allylic carbonates. Efficient allylating agents of carbonucleophiles in palladium-catalyzed reactions under neutral conditions

Abstract: Allylation de β-cetoesters et du malonate de diethyle a l'aide des (alcene-1yl methyl) carbonates. Allylation par le diallylcarbonate de composes nitro, cyano, sulfonyles et carbonyles

Synthesis of repetitive control systems and its application

Abstract: A new control scheme named repetitive control is proposed, in which the controlled variables follow the periodic reference commands with high accuracy. The error convergence condition for linear plants is derived by applying the small gain theorem and a synthesis algorithm using the methods of Kalman Filter and the perfect regulation is presented. We also investigate the repetitive control for a class of nonlinear systems described by x(t)=Ax(t)+Bu(t)+f(x(t)) and y(t)=Cx(t)+Du(t). The stability condition is developed using the passivity theorem. The scheme is applied to the trajectory control for a three-link manipulator.

On estimation of long‐memory time series models

Abstract: Summary This paper discusses estimation associated with the long-memory time series models proposed by Granger & Joyeux (1980) and Hosking (1981) We consider the maximum likelihood estimator and the least squares estimator Certain regularity conditions introduced by several authors to develop the asymptotic theory of these estimators do not hold in this model However we can show that these estimators are strongly consistent, and we derive the limiting distribution and the rate of convergence

Novel palladium-catalyzed reactions of propargyl carbonates with carbonucleophiles under neutral conditions

Abstract: La reaction de carbonates de propargyl(I) avec des carbonucleophiles doux en presence de palladium donne des propenes disubstitues en 2,3 dans des conditions neutres. Les β-cetoesters et les β-dicetones portant deux hydrogenes actifs reagissent avec I dans le rapport 1/1. Il se produit a la fois une C- et une O-alkylation avec ces composes pour donner des methylene-4 dihydro-4,5 furannes et methyl-4 furannes

Change in Microbial Numbers during Thermophilic Composting of Sewage Sludge with Reference to CO2 Evolution Rate

Abstract: Dewatered sewage sludge was composted in a laboratory-scale autothermal reactor in which a constant temperature of 60°C was kept as long as possible by regulating the air feed rate. The change in CO2 evolution rate was measured continuously from the start up through the cessation of compositing. The succession of mesophilic bacteria, thermophilic bacteria, and thermophilic actinomycetes was also observed during the composting. Specific CO2 evolution rates of thermophilic bacteria and actinomycetes in the constant-temperature region of 60°C were assessed quantitatively. It was found that the CO2 evolution rate was attributed to thermophilic bacteria at the initial stage of 60°C and to thermophilic actinomycetes at the later stage of 60°C.

Linewidth reduction of a semiconductor laser by electrical feedback

Abstract: An electrical feedback technique was proposed to stably reduce the linewidth of a semiconductor laser without changing its cavity structure. Calculations and experiments were carried out to reduce the linewidth of a 1.5 μm InGaAsP laser (DFB type) according to the following procedure. A compact Fabry-Perot interferometer was used as a freqeuncy discriminator. The minimum attainable linewidth, limited by the detector noise, was estimated as being narrower than 1 kHz when the reflectance of the interferometer used was higher than 0.9. The minimum linewidth obtained in the experiment was 330 kHz, which was 15 times as narrow as in the case of a free-running laser. The improvements of this experimental result can be expected by simultaneously reducing the AM noise of the laser.

Effect of temperature on composting of sewage sludge.

Abstract: The effect of temperature on the composting reaction of sewage sludge was investigated at 50, 60, and 70°C. The total amount of CO2 evolved and the final conversion of volatile matter were maximum at 60°C., suggesting that the optimal temperature for composting was around 60°C. The specific CO2 evolution rate (moles of CO2 evolved per hour per viable cell) was maximum at 70°C. The isolated thermophilic bacterium which was dominant at 60°C but did not grow at 70°C showed that the rate of O2 consumption measured on the agar plate at 70°C was four times higher than that at 60°C. This showed that the energy yielded from catabolism is rather uncoupled with the anabolism at 70°C in the metabolism of microorganisms indigenous in the compost. A higher respiratory quotient was observed at 70°C than at any other temperature.

Electrical conductivity of yttria-stabilized zirconia single crystals

Abstract: The electrical conductivities of YSZ single crystals with various compositions covering FSZ and PSZ regions were measured by a complex impedance method and a four-probe a.c. method. The conductivities changed significantly as a function of composition. A simple conduction model for PSZ showed that the tetragonal phase is a good oxygen ionic conductor having an activation energy for motion of about 0.8 to 0.9 eV. It is promising for low temperature application of a solid state electrolyte.

Toughened plastics consisting of brittle particles and ductile matrix

Abstract: Studies on plastic alloys consisting of particles of brittle polymers dispersed in the matrices of ductile polymers were undertaken using the miniature polymer evaluation system (CSI Mini-Max System). For the polycarbonate/poly(acrylonitrileco-styrene) system, which had been found to show improved impact strength by Kurauchi, et al. using the conventional methods of molding and mechanical testing, it was verified that the miniature evaluation system gave the same results as those from the conventional methods. Ten other different combinations of ductile and brittle polymers were evaluated by using the miniature evaluation system. Among them the polycarbonate/poly(methyl methacrylate) system is found to be a toughened alloy. From these results, the requirements for the development of toughening in the ductile/brittle systems are discussed.

Conditional Probability and A Posteriori States in Quantum Mechanics

Abstract: In order to develop a statistical theory of quantum measurements including continuous observables, a concept of a posteriori states is introduced, which generalizes the notion of regular conditional probability distributions in classical probability theory. Its statistical interpretation in measuring processes is discussed and its existence is proved. As an application, we also give a complete proof of the Davies-Lewis conjecture that there are no (weakly) repeatable instruments for non-discrete observables in the standard formulation of quantum mechanics, using the notion of a posteriori states.

Analysis of dynamic spectral width of dynamic-single-mode (DSM) lasers and related transmission bandwidth of single-mode fibers

Abstract: A simple formula of the dynamic spectral width of a directly modulated dynamic-single-mode (DSM) laser, and the related maximum transmission bandwidth of a single-mode fiber limited by chromatic dispersion are theoretically given. The dynamic spectral width of a DSM laser is determined by the modulated optical shape and the linewidth enhancement factor α. The spectral width caused by the dynamic wavelength shift is shown to be larger by ( 1 + \alpha^{2} )1/2than that caused by the sideband of the signal of the intensity modulation. Furthermore, the maximum transmission bandwidth of a conventional single-mode fiber with a DSM laser is expressed by using the parameter α and the chromatic dispersion of the fiber. The product of the maximum bit rate and the square root of the fiber length at the wavelength of 1.55 μm is estimated to be about 25 Gbit/s . km1/2.