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991.
Safety and reliability have become important software quality characteristics in the development of safety-critical software
systems. However, there are so far no quantitative methods for assessing a safety-critical software system in terms of the
safety/reliability characteristics. The metrics of software safety is defined as the probability that conditions that can
lead to hazards do not occur. In this paper, we propose two stochastic models for software safety/reliability assessment:
the data-domain dependent safety assessment model and the availability-related safety assessment model. These models focus
on describing the time- or execution-dependent behavior of the software faults which can lead to unsafe states when they cause
software failures. The application of one of these models to optimal software release problems is also discussed. Finally,
numerical examples are illustrated for quantitative software safety assessment and optimal software release policies.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
992.
Toru Nagai Hae Jin Hwang Masaki Yasuoka Mutsuo Sando Koichi Niihara 《Journal of the American Ceramic Society》1998,81(2):425-428
Ceramic nanocomposites with a perovskite-type ferroelectric dispersoid were studied, to introduce ferroelectricity into structural ceramics. Barium titanate (BaTiO3) was found to be phase compatible with magnesia (MgO) during sintering, and a MgO matrix/BaTiO3 nanocomposite was successfully fabricated by a conventional powder mixing and sintering method. The mechanical strength of the nanocomposite was not degraded, although weak BaTiO3 was incorporated into the composite. The BaTiO3 dispersoid was tetragonal or possibly orthorhombic, although the tetragonality, c/a, was decreased from the starting powder. 相似文献
993.
Yasuaki Okamoto Yusaku Arima Michiyasu Hagio Kazuyuki Nakai Satoshi Umeno Yoshio Akai Kei Uchikawa Kazuhiro Inamura Takashi Ushikubo Naonobu Katada Sadao Hasegawa Hisao Yoshida Tsunehiro Tanaka Takaaki Isoda Isao Mochida Koichi Segawa Akio Nishijima Muneyoshi Yamada Hideyuki Matsumoto Miki Niwa Toshio Uchijima 《Applied Catalysis A: General》1998,170(2):211-342
Ten types of 13 wt% MoO3/Al2O3 catalysts were prepared by a conventional impregnation or equilibrium adsorption method using a common extrudate support. These catalysts were subjected to a comprehensive characterization and catalytic reactions to find important preparation parameters in practical preparations. It was demonstrated in the present group study that the formation of crystalline MoO3 was strongly correlated with the Mo segregation on the outer surface of the extrudate. When the amount of the impregnation solution was large (ca. 10 cm3 g-Al2O3−1), a considerably homogeneous distribution and high dispersion of Mo oxide species were attained irrespective of the other preparation parameters. It is suggested that when a pore volume impregnation or incipient wetness technique is employed, drying processes strongly affect the dispersion and distribution of Mo oxide species. Drying at a reduced pressure is suggested to result in a segregation of Mo oxides on the outer surface of the extrudate, and accordingly a formation of crystalline MoO3. 相似文献
994.
Characteristics of MnOy–ZrO2 and Pt–ZrO2–Al2O3 as reversible sorbents of NOx were investigated under dynamic changes in atmosphere. These sorbents can be used reversibly with a change of C3H8 concentration in the reaction gases. Catalytic reduction of NO occurred in the presence of propane, which was more pronounced on Pt–ZrO2–Al2O3 than on MnOy-ZrO2 due to high activity of Pt surface for this reaction on MnOy in MnOy–ZrO2. The sorption was observed as soon as the atmosphere changed from a reducing to an oxidizing one. This implies that a high equilibrium partial pressure of O2 is necessary for NO uptake since the sorbed NO−3 species becomes stable. The beginning of NOx desorption atmospheres was somewhat dependent on the amount of stored NOx. The presence of propane in the gas phase strongly affected the characteristic sorption and desorption properties of MnOy–ZrO2 and Pt–ZrO2–Al2O3. The sorption and desorption properties are different for MnOy–ZrO2 and Pt–ZrO2–Al2O3, since the noble metal or metal oxide possesses unique activity for the NO reaction with C3H8 and the amount of oxygen available for oxidative sorption of NO. 相似文献
995.
Ryo Koyama Koichi Iwata Yoshinori Hayashi Suzuro Hitomi Ikuko Shibuta Akihiko Furukawa Sayaka Asano Tadayoshi Kaneko Yoshiyuki Yonehara Masamichi Shinoda 《International journal of molecular sciences》2021,22(21)
Pain is one of the most severe concerns in tongue cancer patients. However, the underlying mechanisms of tongue cancer pain are not fully understood. We investigated the molecular mechanisms of tongue cancer-induced mechanical allodynia in the tongue by squamous cell carcinoma (SCC) inoculation in rats. The head-withdrawal threshold of mechanical stimulation (MHWT) to the tongue was reduced following SCC inoculation, which was inhibited by intracisternal administration of 10Panx, an inhibitory peptide for pannexin 1 (PANX1) channels. Immunohistochemical analyses revealed that the expression of PANX1 was upregulated in the trigeminal spinal subnucleus caudalis (Vc) following SCC inoculation. The majority of PANX1 immunofluorescence was merged with ionized calcium-binding adapter molecule 1 (Iba1) fluorescence and a part of it was merged with glial fibrillary acidic protein (GFAP) fluorescence. Spike frequencies of Vc nociceptive neurons to noxious mechanical stimulation were significantly enhanced in SCC-inoculated rats, which was suppressed by intracisternal 10Panx administration. Phosphorylated extracellular signal-regulated kinase (pERK)-immunoreactive (IR) neurons increased significantly in the Vc after SCC inoculation, which was inhibited by intracisternal 10Panx administration. SCC inoculation-induced MHWT reduction and increased pERK-IR Vc neuron numbers were inhibited by P2X7 purinoceptor (P2X7R) antagonism. Conversely, these effects were observed in the presence of P2X7R agonist in SCC-inoculated rats with PANX1 inhibition. SCC inoculation-induced MHWT reduction was significantly recovered by intracisternal interleukin-1 receptor antagonist administration. These observations suggest that SCC inoculation causes PANX1 upregulation in Vc microglia and adenosine triphosphate released through PANX1 sensitizes nociceptive neurons in the Vc, resulting in tongue cancer pain. 相似文献
996.
Nylon‐11 oligomer was utilized as a matrix to prepare a composite containing nano‐sized gold particles. Nylon‐11 oligomer was prepared by a thermal degradation of a commercial nylon‐11 in vacuum. Weight‐average molecular weight of the oligomer was in a range from 500 to 800. Nylon‐11 oligomer was formed into a film, and then gold was vapor‐deposited onto the oligomer film. The gold‐colored oligomer film turned a transparent red after a heat treatment at 120°C. Transmission electron microscopy showed an isolated distribution of nano‐sized gold particles in the red film of the oligomer. The gold particles were stable in the oligomer for more than a year, and they were dissolved in CH2Cl2 to produce a stable colloidal solution. These results suggest that the gold particles were not only dispersed in the oligomer film, but they were stabilized by the nylon‐11 oligomer to form a composite. IR spectrum of the composite showed that N H groups of the nylon‐11 oligomer were responsible for the interaction between the gold particles and the oligomer. Pulse 1H‐NMR measurement suggested that an active molecular motion of the nylon‐11 oligomer caused the dispersion of the gold particles. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1654–1661, 1999 相似文献
997.
Koichi Takaki Kunio Sayama Atsushi Takahashi Tamiya Fujiwara Masakatsu Nagata Motoyuki Ono Muaffaq Achmad Jani 《Electrical Engineering in Japan》1999,127(4):9-17
Temperature rises of a birefringent substrate (LiNbO3) have been measured in an argon RF discharge plasma. The measurement method is based on monitoring the variation of natural birefringence with temperature by laser interferometry. Using this method, the dependence of substrate temperature rise on applied RF power and gas pressure has been investigated. The evaluation of the temperature curves shows that heat flux from the plasma toward the substrate is independent of time and temperature. The magnitude of the flux differs largely from the applied power, and is approximately 0.4% of the power. By measuring the electron density, electron temperature, and plasma potential with a Langmuir probe, the energy of the ions incident on the substrate is estimated. The ion flux toward the substrate is calculated from the energy of ions and is compared with the measured heat flux. The dependence on the applied power is in approximate agreement between those fluxes. The temperature distribution over the substrate thickness is simulated numerically using the finite difference method. © 1999 Scripta Technica, Electr Eng Jpn, 127(4): 9–17, 1999 相似文献
998.
Keiichiro Tojo Minoru Kurosawa Koichi Oka Toshiro Higuchi 《Electrical Engineering in Japan》1999,128(4):94-101
The application of single‐bit digital signal processing to mechanical control systems has already been proposed by the authors. Multibit A/D converters have been improved to a high level. But it is difficult to improve high‐resolution A/D by the latest semiconductor technologies. A single‐bit digital signal can be generated by a delta‐sigma modulator. Single‐bit digital signal has a small quantized error at low frequency. Then with this single‐bit digital signal processing, high resolution on controlling such a narrow‐bandwidth mechanical system will be realized. In this paper, resolution of analog, multibit, and single‐bit control systems is estimated via simulation. According to the results of simulations, a single‐bit control system has a higher resolution than a multibit system under conditions of equal bit rates. © 1999 Scripta Technica, Electr Eng Jpn, 128(4): 94–101, 1999 相似文献
999.
Kazuhiko Kato Akinobu Murata Koichi Sakuta 《Progress in Photovoltaics: Research and Applications》1998,6(2):105-115
The concerns about environmental impacts of photovoltaic (PV) power systems are growing with the increasing expectation of PV technologies. In this paper, three kinds of silicon-based PV modules, namely single-crystalline silicon (c-Si), polycrystalline silicon (poly-Si) and amorphous silicon (a-Si) PV modules, are evaluated from the viewpoint of their life-cycle. For the c-Si PV module it was assumed that off-grade silicon from semiconductor industries is used with existing production technologies. On the other hand, new technologies and the growth of production scale were presumed with respect to the poly-Si and a-Si PV modules. Our results show that c-Si PV modules have a shorter energy pay-back time than their expected lifetime and lower CO2 emission than the average CO2 emission calculated from the recent energy mix in Japan, even with present technologies. Furthermore the poly-Si and the a-Si PV modules with the near-future technologies give much reduction in energy pay-back times and CO2 emissions compared with the present c-Si PV modules. The reduction of glass use and the frameless design of the PV module may be effective means to decrease them more, although the lifetime of the PV module must be taken into account. © 1998 John Wiley & Sons, Ltd. 相似文献
1000.
Development of SF6 gas-insulated switches that have a long service life and are highly reliable at medium voltage ratings require arc erosion of contacts in SF6 gas to be decreased. The effects of SF6 gas pressure and magnetic field for arc blow-out on erosion were studied experimentally in detail using sintered Cu-W contacts. The test current, SF6 pressure and magnetic field were 100 to 400 A, 0.1 to 0.6 MPa and 0 to 50 mT, respectively. The results show that the arc erosion rate increased linearly with the SF6 pressure. The magnetic field effectively reduced anode erosion (i.e., the application of a mere 50 mT lowered the erosion rate to 1/3 to 1/4). These phenomena may be attributed, respectively, to the increase in evaporation rate according to the shrinkage of arcing spot areas caused SF6 pressure and a decrease of the evaporation rate correlating to high-speed movement of the arcing spot on the anode by the magnetic field. However, the cathode erosion was insensitive to the magnetic field. The influence of both W grain size and composition ratio, Cu:W, on the erosion rate was also studied. The smaller W grain at Cu content of 50 to 70 wt.% was found to be best for suppression of erosion under the present conditions. Further, the increase of N2 mixture ratio to SF6 under constant total gas pressure greatly decreased contact erosion. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 118 (1): 41–51, 1997 相似文献