Evaluation for distance learning scheme on distributed multiple server system

A distributed multiple server system is designed and implemented with Web-DB based services for distance learning as well as emergency communication. The system has employed multiple servers located in a distributed campus network environment. Each server of the system has multi-core processors. With so-called “server virtualization” technology, some programs are executed in parallel (on the virtual servers) so that such a system can efficiently perform several functions. For example, two or more application services can be performed simultaneously as “cloud services” on the whole system. The system can provide distance learning scheme for educational tool, at the same time it can also support Web-based surveillance facilities for emergency contact. With qualitative and quantitative approach, trial evaluation of system has been performed in some classrooms of distributed campus. And users can obtain some good results from the above evaluation.     

Applicability of the generalized scaling law to a pile-inclined ground system subject to liquefaction-induced lateral spreading

The generalized scaling law is based on the concept of two-stage scaling and allows currently available centrifuge facilities to model a large-scale prototype expanding over the spatial dimension ranging from 30 m or larger subject to earthquake motions. This paper presents the results of investigation on the applicability of the generalized scaling law to the fully nonlinear regime of soil-structure system with the induced strain level of 10% in the order of magnitude. The centrifuge model tests performed in this study under the modeling of models scheme consist of a pile model embedded in a inclined ground subject to liquefaction-induced lateral spreading. Four different centrifugal accelerations ranging from 13g to 50g are used whereas the actual size of the physical model is kept constant with an overall scaling factor of 1/100. The models are exposed to tapered sinusoidal input accelerations of frequency 0.59 Hz and amplitude 3.0 m/s² in prototype scale, and the results are compared in terms of prototype by applying the generalized scaling law. As for the response of the ground during shaking, essentially identical accelerations and excess pore water pressures are recorded for all cases, while the lateral displacement shows a variation ranging from 5% to 9% in terms of shear strain due to a slight variation in experimental conditions (e.g., input peak acceleration, achieved density distribution). Practically the same responses are measured among the cases in the dissipation phase of excess pore water pressure. With regard to pile behavior, nearly identical responses for the lateral displacements and bending moments are obtained for all cases both during and after shaking. These results demonstrated that the generalized scaling law is applicable to the fully nonlinear regime of soil-structure system subject to the cumulative shear strain in the order of 10% due to cyclic mobility of sands during earthquakes.     

Temperature dependence of luminescence from a silica glass under in-reactor irradiation

We have investigated in-reactor luminescence (IRL) from a silica glass at temperatures ranging from 100 K to 250 K. The IRL consists mainly of a broad emission band peaked at 2.7 eV assigned to oxygen deficient centers produced in the silica glass under the in-reactor irradiation. The 2.7 eV emission intensity linearly increased with the irradiation time and its increasing rate was larger for higher irradiation temperatures. However, this temperature dependence is inconsistent with that for the defect production rate and the cause is not clear at present. The initial intensity of the 2.7 eV IRL band increases with temperature, showing an activation energy of ca 21 meV. This value is much lower than those observed in the temperature dependence of the 2.7 eV photoluminescence (PL) and the cathodeluminescence (CL) induced by 8 keV electron irradiation. These results suggest that in IRL, some electrons excited to higher energy levels than the luminescence level are likely transferred to the luminescence state without thermal activation, resulting in a lower activation energy in their temperature dependence.     

Colored Fluorescent Silk Made by Transgenic Silkworms

Silk is a protein fiber used to weave fabrics and as a biomaterial in medical applications. Recently, genetically modified silks have been produced from transgenic silkworms. In the present study, transgenic silkworms for the mass production of three colors of fluorescent silks, (green, red, and orange) are generated using a vector originating from the fibroin H chain gene and a classical breeding method. The suitability of the recombinant silks for making fabrics is investigated by harvesting large amounts of the cocoons, obtained from rearing over 20 thousand silkworms. The application of low temperature and a weakly alkaline solution for cooking and reeling enables the production of silk fiber without loss of color. The maximum strain tolerated and Young's modulus of the fluorescent silks are similar to those of ordinary silk, although the maximum stress value of the recombinant silk is slightly lower than that of the control. Fabrics with fluorescent color are demonstrated using the recombinant silk, with the color persisting for over two years. The results indicate that large amounts of genetically modified silk can be made by transgenic silkworms, and the silk is applicable as functional silk fiber for making fabrics and for use in medical applications.     

Improvement of the Nelder-Mead method using Direct Inversion in Iterative Subspace

Optimization and Engineering - The Nelder-Mead (NM) method is a popular derivative-free optimization algorithm owing to its fast convergence and robustness. However, it is known that the method...     

Effect of Polyethylenimine on Hydrolysis and Dispersion Properties of Aqueous Si3N4 Suspensions

The roles of polyethylenimine (PEI) in the hydrolysis and dispersion properties of aqueous Si₃N₄ suspensions were studied in terms of the hydrolysis, adsorption, electrokinetic, and rheological measurements. It was found that the pH change of the suspensions in the acidic environment could be minimized in the presence of ≥0.5 dwb% PEI. The ammonia and oxygen measurements suggest that this phenomenon is primarily attributed to the buffer mechanism generated by the ionized PEI, instead of the protection mechanism. The constant pH enables the suspensions to retain a better stability with time at acidic pH. The adsorption of PEI on Si₃N₄ is a high-affinity type at highly basic pH, but is a low-affinity type at acidic pH. As the PEI amount increases, the adsorption shifts the isoelectric point (IEP) of Si₃N₄ from pH 5.9 to pH ∼11 until complete coverage is attained. The stability of Si₃N₄ suspensions is found to depend strongly on the saturated adsorption of PEI, which is as a function of the pH and PEI amount. Once the saturated adsorption limit is reached, the excess free PEI molecules become more detrimental to the stability with increased solid loading. The stabilization mechanisms of Si₃N₄ suspensions by PEI were discussed in detail.     

High temperature coefficients of resistance of VO2 films grown by excimer-laser-assisted metal organic deposition process for bolometer application

With bolometer application in mind, we prepared VO₂ films on TiO₂ (001) substrates by an excimer-laser-assisted metal organic deposition process at 300 °C or less. A metal-to-insulator transition of VO₂ is expected to induce high temperature coefficient of electrical resistance (TCR) useful for high-performance infrared sensors, but the practical use of crystalline VO₂ films has been prevented due to the accompanied wide hysteresis. In this study, by forming the epitaxial phase only near the substrate interface, the transition of the film was successfully broadened and the hysteresis disappeared. The maximum TCR of the film was more than -10%/°C near room temperature, and the temperature range in which TCR was higher than -4%/°C was very wide (280-320 K).     

Simulation study of eutrophication in Hiroshima Bay: Simulation of particulate and dissolved organic matter using cyclic transformation of carbon

A phytoplankton model, which includes a carbon cycle combined with a constant current obtained by the computation of tidal currents, was applied to the coastal region (Hiroshima Bay, Japan). The transformation rate constants for the carbon cycle were experimentally evaluated.The seasonal variations of particulate and dissolved organic matter by the simulation model were reasonably consistent with the field data. Carbon concentration increased by primary production in the upper layer was approx. 10 times that augmented by loading of carbon from land at the shore in summer. Sinking plays an important role in the elimination of particulate organic matter. On the other hand, horizontal advection and turbulent diffusion are important factors for the diminution of dissolved organic matter.     

Measurement and correlation of the solid-liquid-gas equilibria for carbon dioxide + normal chain saturated aliphatic hydrocarbon systems

The pressure p-temperature T projections of solid-liquid-gas (S-L-G) three-phase coexistence lines for the carbon dioxide + tetradecanoic acid (C₁₄H₂₈O₂) system, the carbon dioxide + hexadecanoic acid (C₁₆H₃₂O₂) system, and the carbon dioxide + 1-hexadecanol (C₁₆H₃₄O) were measured by the first melting point method in which the initial appearance of the liquid phase was observed. The profiles of the p-T projections of the S-L-G lines for the carbon dioxide + acid systems are similar to each other, the S-L-G equilibria for the carbon dioxide + acid systems are, however, different from that for the carbon dioxide + 1-hexadecanol systems. The experimental p-T projections of the S-L-G lines were also correlated by the Peng-Robinson equation of state and the van der Waals type mixing rules with two binary interaction parameters introduced into attraction term and size terms, respectively. The present model gave good correlation results for all of the experimental S-L-G lines with maximum average absolute relative deviations of 0.075% for the carbon dioxide + tetradecanoic acid system, 0.14% for the carbon dioxide + hexadecanoic acid system and 0.28% for the carbon dioxide + 1-hexadecanol system, respectively.     

Self-organization of conceptual generalities and pattern-directed learning

Human expert decision makers can be characterized by their ability to perceive a hypothetical conceptual generality or pattern that is underlying a given collection of objects. The conventional cluster analysis is unable to generate such patterns since its clustering process is far from what the human experts actually do. That is, human experts form some concepts inductively from individual observations based on the conceptual “meaning” which the objects have. In this paper, by introducing an idea of prototype theory from a psychological domain with respect to human concept formation, an algorithm for human classification process is proposed. Based on this, the role of human generalization capability in his classification process is discussed with respect to the background semantic knowledge. The algorithm can be roughly divided into two phases; inductive prototype formation from training examples in a bottom-up fashion, and pattern-directed clustering of the instances being affected by the acquired concepts in a top-down fashion. Using a schematically-modelled example, the algorithm is illustrated with its implemented results. Our modelling method for the human classification process can be utilized for conceptual clustering that classifies a number of unknown objects into a distinguished group being affected by pre-acquired concepts.