Stereochemical studies of the electrolytic reactions of organic compounds—XIII. Electrolytic reduction of ketones having a chirality center at their α-positions to the corresponding diastereomeric alcohols

Optically-inactive ketones, which have a chirality center at their α-positions, were electrolytically reduced to the corresponding diastereomeric secondary alcohols. The isomeric ratio of the alcohols depended on the substituent of the ketones and on electrolytic conditions. It is noticeable that a ketone having a cyclohexyl group at the α-position gave the anti-Cram alcohol (the diastereomer expected to form less advantageously from the Cram rule) as a major diastereomer under a variety of electrolytic conditions. From stereochemical data obtained, stereochemical courses for the reduction were tentatively proposed.     

Application of genetic algorithms to service restoration in distribution systems

Service restoration in distribution systems can be formulated as a combinatorial optimization problem to determine power sources for each load considering radial network constraints and power source limits. Until now, the problem has been considered using conventional methods, e.g., the branch-and-bounds method, expert system, neural networks, and fuzzy reasoning. Recently, Genetic Algorithms (GA) have been recognized as one of the efficient methods for solving large combinatorial optimization problems. The method can perform parallel search, and can more easily search optimal solutions. This paper presents an application of GA to service restoration in distribution systems. The feasibility of the proposed method is demonstrated on a typical distribution system model. The result shows that the method can solve the problem efficiently, and this tendency becomes dominant by increasing problem dimensions.     

A heuristic approach for actuator layout designs in deformable mirror devices based on current value optimization

Structural and Multidisciplinary Optimization - Deformable mirrors are vital components in fundus imaging modality incorporating adaptive optics systems. The application of precisely controlled...     

Fast unsupervised adaptation based on efficient statistics accumulation using frame independent confidence within monophone states

This paper proposes a fast unsupervised acoustic model adaptation technique with efficient statistics accumulation for speech recognition. Conventional adaptation techniques accumulate the acoustic statistics based on a forward–backward algorithm or a Viterbi algorithm. Since both algorithms require a state sequence prior to statistic accumulation, the conventional techniques need time to determine the state sequence by transcribing the target speech in advance. Instead of pre-determining the state sequence, the proposed technique reduces the computation time by accumulating the statistics with state confidence within monophone per frame. It also rapidly selects the appropriate gender acoustic model before adaptation, and further increases the accuracy by employing a power term after adaptation. Recognition experiments using spontaneous speech show that the proposed technique reduces computation time by 57.3% while providing the same accuracy as the conventional adaptation technique.     

Properties of rapidly deposited amorphous hydrogenated carbon films

The properties of hydrogenated amorphous carbon films prepared by the rapid and low-temperature decomposition of toluene in an r.f. glow discharge have been investigated. The films are composed of a mixture of sp² and sp³ bonded carbons. Measurements of the optical gap show that the optical gap decreases with an increase of the r.f. power and increases with increasing pressure. The room-temperature dielectric constant decreases with increasing pressure with a dielectric loss tangent of 1%.     

Degradation of Superconductivity in Annealed Irradiated Bi2Sr2CaCu2O8+δ Single Crystals During Exposure to Air

As for irradiated Bi₂Sr₂CaCu₂O₈₊ single crystals annealed in flowing N₂ atmosphere, flowing O₂ atmosphere, and air, their superconductivity was degraded during exposure to air. The degradation of superconducting transition temperature T _c is attributed to the doping of oxygen. The small recovery of T _c may be related to the redistribution of oxygen. The superconductivity of samples annealed in N₂ atmosphere and air is more stable than that of the sample annealed in O₂ atmosphere during exposure to air.     

Physics-based flow estimation of fluids

We present a physics-based method to compute the optical flow of a fluid. In most situations, gray level changes in an image do not provide sufficient information to completely ascertain optical flow, necessitating the use of a supplementary constraint. For this, the smoothness constraint is often employed. This constraint is, however, general and does not express well a priori knowledge of a specific object. We therefore propose a method in which physical equations describing the object are used as supplementary constraints. In this way, more accurate flow estimation can be achieved. The physical model employed is a combination of the continuity equation and Navier-Stokes’ equations. After describing how we integrate these equations into fluid flow estimation, we demonstrate the effectiveness of the proposed method by presenting experimental results of its application to simulated and real Karman flows.     

A cyber attack-resilient server inspired by biological diversity

This paper describes a novel cyber attack-resilient server inspired by the concept of biological diversity. The server consists of several virtual machines running different operating systems and different implementations of the same server protocol specification. This approach is based on the observation that not all implementations are affected by the same vulnerability, except for vulnerabilities in specifications and on shared libraries. A prototype system was built and tested to evaluate the continuity of the service. The results showed that, by exploiting a vulnerability, the prototype system could suppress downtime of the DNS service to less than 4 s without false positives.     

Precipitates caused by prolonged high-temperature annealing in floating zone silicon wafer grown from Czochralski single-crystal rod

The behavior of precipitates in a floating zone silicon crystal produced from a Czochralski single-crystal ingot has been studied. Large precipitates of α-Si₃N₄ crystal, having a dimension of about 2 μm, were formed at the mid-depth in the wafer by annealing at a high temperature in an ambient N₂ (70%)+O₂ (30%) atmosphere. The number of precipitates detected by cross-sectional X-ray topography increased with increasing annealing time. Because preannealing accompanying silicon oxidation in an ambient Ar+O₂ atmosphere prevented the precipitates formation, interstitial silicon is considered to eliminate the origin of precipitate.