Performance-aware server architecture recommendation and automatic performance verification technology on IaaS cloud

In this paper, we propose a server architecture recommendation and automatic performance verification technology, which recommends and verifies appropriate server architecture on Infrastructure as a Service (IaaS) cloud with bare metal servers, container-based virtual servers and virtual machines. Recently, cloud services are spread, and providers provide not only virtual machines but also bare metal servers and container-based virtual servers. However, users need to design appropriate server architecture for their requirements based on three types of server performances, and users need much technical knowledge to optimize their system performance. Therefore, we study a technology that satisfies users’ performance requirements on these three types of IaaS cloud. Firstly, we measure performance and start-up time of a bare metal server, Docker containers, KVM (Kernel-based Virtual Machine) virtual machines on OpenStack with changing number of virtual servers. Secondly, we propose a server architecture recommendation technology based on the measured quantitative data. A server architecture recommendation technology receives an abstract template of OpenStack Heat and function/performance requirements and then creates a concrete template with server specification information. Thirdly, we propose an automatic performance verification technology that executes necessary performance tests automatically on provisioned user environments according to the template. We implement proposed technologies, confirm performance and show the effectiveness.     

A novel quarter‐wave retardation film for improving viewing angle properties in time‐sequential stereoscopic 3D‐LCDs

We have successfully developed a quarter‐wave retardation film (QWF) for wide viewing angle 3D liquid crystal displays (3D‐LCDs) that provides high luminance, low crosstalk, low color change, and low head‐tilt‐angle dependency. It was found that the out‐of‐plane retardation (Rth) of the QWF in the LCD needs to be close to 0 nm in order to improve the 3D display properties at an off‐axis position and that the in‐plane retardation (Re) needs to be adjusted from 120 to 130 nm to achieve low color change with head tilting. We adopted a coating process for making our QWF because of its potential for retardation control. 3D‐LCDs with this QWF whose Rth was nearly zero had high performance and allowed off‐axis other than on‐axis.     

Simulated crepitus and its reality-based specification using wearable patient dummy

Physical therapists are trained in manual examination techniques to test the impaired motor functions of patients. In this study, we have introduced a wearable robotic dummy joint to simulate disordered joint resistances or behaviors to support physical therapists in learning such techniques. We developed a discontinuous joint friction model based on a stick-slip phenomenon to simulate knee joint resistances caused by crepitus, a typical symptom accompanied by osteoarthritis. Practicing therapists participated in a reality-based evaluation test and specified acceptable parameter sets to adjust the simulated crepitus for the exoskeletal patient robot. The simulated crepitus and wearable dummy joint are expected to support the training of physical therapists.     

Technical evolution of permanent magnet synchronous motors for home appliances

This paper reports on the highly efficient motor technologies used in home appliances in Japan. The permanent magnet synchronous motor (PMSM) is especially suitable because the use of permanent magnets does not require any extra current to produce magnetic power in the rotor, or any other kind of energy. In Japan, there has been a rapid shift from induction motors to PMSMs, and in this paper we will show several examples of PMSMs as applied to the home appliance field. It can be seen that great improvements have been made in high‐efficiency motor technologies. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Learning of real robot's inverse dynamics by a forward‐propagation learning rule

A forward‐propagation learning rule (FPL) has been proposed for a neural network (NN) to learn an inverse model of a controlled object. A feature of FPL is that the trajectory error propagates forward in NN and appropriate values of two learning parameters are required to be set. FPL has only been simulated to several kinds of controlled objects such as a two‐link arm in a horizontal plane. In this work, we applied FPL to AIBO and showed the validity of FPL on a real controlled object. At first, we tested a learning experiment of an inverse dynamic of a two‐link arm in a sagittal plane with viscosity and Coulomb friction by computer simulation. In this simulation, a low‐pass filter (LPF) was applied to realized trajectories because coulomb friction vibrates them. From the simulation results, we found that the learning process is stable by some adequate sets of the learning parameters although it is more sensitive to the values of the parameters owing to friction and gravity terms. Finally, we tested applying FPL to motor control of AIBO's leg. The inverse dynamics model was acquired by FPL with only about 150 learning iterations. From these results, the validity of the FPL was confirmed by the real robot control experiments. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(4): 38–48, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20456     

Comparison of electronic structures of doped ZnS and ZnO calculated by a first-principle pseudopotential method

Electronic band calculations of doped and undoped ZnO and ZnS have been done using density functional theory under the local density approximation so as to clarify the reason of the difference in behaviors of doped ZnO and ZnS. The reason why the electrical conductivity of ZnS is difficult to be increased by doping was discussed. In the case of doped ZnS, an impurity level was generated at deep position below the bottom of the conduction band of the host ZnS lattice and Fermi level was located at this impurity level. On the contrary, the shape of the density of states curve and the band structures of doped and undoped ZnO are alike with each other and the donor band is hybridized with the conduction band of the ZnO host material. This seems to result in contribution of doped electrons to electrical current in the case of doped ZnO.     

Speed control system and design of resonant system with disturbance observer

In industrial motor drive systems such as industrial plants and industrial robots, a torsional vibration often is generated because of the elastic elements in torque transmission. This vibration makes it difficult to achieve quick responses of speed and may result in damage to the plant. Such systems simply are modeled as a two mass system. The shaft torque feedback system with the disturbance observer, which is called “resonance ratio control,” is proposed to suppress the vibration for the two-mass system. In this paper, the design of controller gains in the shaft torque feedback system is examined considering not only the control performance such as the vibration suppression and dynamic responses, but also the robust stability against the noise and the model uncertainties. This paper shows the validity of the control system and the examinations by several experiments.