Fundamental study of high Q‐factor RF spiral inductor using carbonyl‐iron/epoxy composite magnetic core

In order to increase the Q‐factor of an RF spiral inductor used in the RF front‐end circuit of smartphone handsets, we introduced a carbonyl‐iron/epoxy composite magnetic core in the air‐core spiral inductor. The composite magnetic core, which was made by metal‐mask printing, consisted of carbonyl‐iron powder of 1.1 μm mean diameter and an epoxy resin matrix. We found that the 45 vol.% CIP composite magnetic core had a saturation magnetization of 0.9 T, relative permeability of ∼6, and loss tangent (tan δ) of ∼0.2 at 1 GHz. A two‐turn copper spiral inductor fabricated with the composite magnetic core filled only in the spacing between the conductor lines showed a clear Q‐factor increase of ∼29% compared to the air‐core spiral inductor at 1 GHz. Thus we obtained a substantial increase in the Q‐factor by the embedded composite magnetic core in the spacing between the conductor lines. The main reason for this is that the magnetic flux passing through the conductor lines was decreased by the magnetic core embedded in the spacing between conductor lines as a result of the magnetic flux passing mainly through the embedded magnetic core. Therefore, proximity effect is suppressed in the conductor line of the spiral coil. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Low‐Noise Fully Differential Amplifiers Using JFET‐CMOS Integration Technology for Smart Sensors

In this paper, CMOS‐based low‐noise amplifiers with JFET‐CMOS technology for high‐resolution sensor interface circuits are presented. A differential difference amplifier (DDA) configuration is employed to realize differential signal amplification with very high input impedance, which is required for the front‐end circuit in many sensor applications. Low‐noise JFET devices are used as input pair of the input differential stages or source‐grounded output load devices, which are dominant in the total noise floor of DDA circuits. A fully differential amplifier circuit with pure CMOS DDA and three types of JFET‐CMOS DDAs were fabricated and their noise performances were compared. The results show that the total noise floor of the JFET‐CMOS amplifier was much lower compared to that of the pure CMOS configuration. The noise‐reduction effect of JFET replacement depends on the circuit configuration. The noise reduction effect by JFET device was maximum of about − 18 dB at 2.5 Hz. JFET‐CMOS technology is very effective in improving the signal‐to‐noise ratio (SNR) of a sensor interface circuit with CMOS‐based sensing systems. © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Enzymatic Analysis of Positional Distribution of Fatty Acids in Solid Fat by 1,3-Selective Transesterification with Candida antarctica Lipase B

A protocol for the analysis of the positional distribution of fatty acids (FA) in solid triacylglycerols (TAG) was developed using sn-1(3) selective alcoholysis catalyzed by immobilized Candida antarctica lipase B (CALB). One part by weight of solid fat and ten parts by weight of ethanol (99.5 %) were warmed to liquefy the fat. After adding 0.44 parts by weight of CALB, the mixture was shaken at 50 °C for 10 min then at 30 °C for 2.8 h. The recovery of 2-MAG after the 3-h transesterification reaction was ca. 85 % of the maximum theoretical yield (33 mol%), with the loss of 15 % attributable to the acyl migration from sn-2 to sn-1(3). The recovery was similar to that of the solvent-free alcoholysis of structured lipids, 1,3-dipalmitoyl, 2-oleoyl glycerol and 1,3-dioleoyl, 2-palmitoyl glycerol, conducted at 30 °C for 3 h. In contrast, the acyl migration from sn-1(3) to sn-2 was hardly observed. Because the detected acyl migration was only in the direction of sn-2 to sn-1(3), and not vice versa, it is proposed to determine the FA composition of the sn-2 position of TAG by the gas chromatographic analysis of 2-MAG fraction recovered from the enzymatic reaction mixture, and the FA composition of sn-1(3) position by a mass balance using the FA composition of TAG and of the sn-2 position as inputs. The procedure was successfully applied to palm oil and shea butter, and docosahexaenoic acid (DHA)-rich single cell oil from Aurantiochytrium sp. KH105 for the first time.     

An architecture framework for an adaptive extensible processor

To improve the performance of embedded processors, an effective technique is collapsing critical computation subgraphs as application-specific instruction set extensions and executing them on custom functional units. The problem with this approach is the immense cost and the long times required to design a new processor for each application. As a solution to this issue, we propose an adaptive extensible processor in which custom instructions (CIs) are generated and added after chip-fabrication. To support this feature, custom functional units are replaced by a reconfigurable matrix of functional units (FUs). A systematic quantitative approach is used for determining the appropriate structure of the reconfigurable functional unit (RFU). We also introduce an integrated framework for generating mappable CIs on the RFU. Using this architecture, performance is improved by up to 1.33, with an average improvement of 1.16, compared to a 4-issue in-order RISC processor. By partitioning the configuration memory, detecting similar/subset CIs and merging small CIs, the size of the configuration memory is reduced by 40%.     

Realization of Dynamic Walking and Running of the Quadruped Using Neural Oscillator

In the present study we attempt to induce a quadruped robot to walk dynamically on irregular terrain and run on flat terrain by using a nervous system model. For dynamic walking on irregular terrain, we employ a control system involving a neural oscillator network, a stretch reflex and a flexor reflex. Stable dynamic walking when obstructions to swinging legs are present is made possible by the flexor reflex and the crossed extension reflex. A modification of the single driving input to the neural oscillator network makes it possible for the robot to walk up a step. For running on flat terrain, we combine a spring mechanism and the neural oscillator network. It became clear in this study that the matching of two oscillations by the spring-mass system and the neural oscillator network is important in order to keep jumping in a pronk gait. The present study also shows that entrainment between neural oscillators causes the running gait to change from pronk to bound. This finding renders running fairly easy to attain in a bound gait. It must be noticed that the flexible and robust dynamic walking on irregular terrain and the transition of the running gait are realized by the modification of a few parameters in the neural oscillator network.     

A self-organizing map with twin units capable of describing a nonlinear input-output relation applied to speech code vector mapping

This paper describes a new type of self-organizing map (SOM) with twin units as opposed to the single unit type conventional SOM proposed by Kohonen. The present self-organizing map with twin units (TW-SOM) can describe a nonlinear input-output relation with high accuracy. It is applied to voice conversion problem from bone conduction voice to air conduction voice (nonlinear code vector mapping), and its superiority over the conventional method using Linde-Buzo-Gray (LBG) algorithm is discussed. The tone quality of the converted voice is examined not only from the quantization distortion viewpoint, but also from the auditory sensation viewpoint through actual listening tests. The enhancement of the tone quality was experimentally confirmed.     

Distributed memory implementation of KLIC

This paper describes external reference management and distributed unification in a distributed implementation of a concurrent logic programming language KL1. This implementation is based on the KLIC system. KLIC has a feature calledgeneric objects that enable easy modification and extension of the system without changes in the core implementation. This distributed implementation is built upon the same core and external references are represented using generic objects. Unification operations are defined as methods of generic objects. Since creation of interprocessor reference loops cannot be avoided, we studied a new unification scheme that can cope with interprocessor reference loops. We built several experimental distributed systems that all demonstrate reasonable efficiency.     

Product design logic for an intelligent product modelling system

Recent research in CAD systems has been conducted to realize intelligent processing. Several CAD systems and product modelling systems have been developed using AI techniques. However, in order to develop more intelligent CAD systems, the design logic which connects the functional requirement to the geometric and the technological information of the designed product must be evaluated.

A product model used in such intelligent CAD systems has to include not only the geometric and the technological information of the product but also the designer's thought process which explains the design logic.

Design logic is generally divided into two parts. One is the generalized design logic which is commonly used in the conceptual design of mechanical products. The other is the product specified design logic which is used in the fundamental and detailed design phase. Different logic is applied to each product. This type of design logic is often used in modification design and compilation design, where the dimensions of parts have to be modified according to different functional requirements. When the dimensions and accuracies of the products are defined in connection with the functional requirements through design logic, the CAD system can automatically make decisions according to the given requirements. In this paper, suitable presentation formats and processing functions for these two types of design logic are discussed.

The importance of design logic in product modelling is proven through several case studies in this paper. As a conclusion, the intelligent product modelling system is developed, which should expedite the progress of design automation in the near future. In conceptual design, the design logic is processed in the modelling system and the product structure, with the technological information decided automatically from the functional requirement. Automation in the detailed design phase is also facilitated by the modelling system using the product specified design logic in the product model.     

Application of induction motor speed sensorless vector control to railway vehicle traction

Pulse generators (PGs) are equipped to detect the rotor frequency of induction traction motors for torque control in railway vehicle traction field. Eliminating PGs is preferable from the viewpoints of increasing the reliability of the traction system, reduction of both the initial and maintenance cost, and downsizing induction traction motors. Expecting those advantages, we have been studying the application of a sensorless control method to induction traction motor control. Prior to some reports of studies and tests to apply speed sensorless strategy to railway vehicle traction we launched ideas to apply the speed sensorless control strategy and results of the studies and tests. In this paper, we present the novel control method for railway vehicle traction and some results of theoretical study and tests. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(2): 69–77, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20273