Optimum combination of operating parameters in abrasive cut-off

For optimization of abrasive cut-off operation, wheel wear equation must be identified before the operation is optimized. The equation is obtained by using GMDH algorithm with successive determination of trends containing interactive terms. In the model equation factors of grinding fluid are taken into consideration in addition to the factors of wheel, work material, feed (table speed) and wheel speed. For the identification of the model wheel wear tests are performed under the experimental design treating the above-mentioned factors as independent variables. The grinding ratio (output in the model) can be predicted for combinations of various factors using the model. With the wheel wear equation and machining cost model, the optimum combination of wheel, fluid, feed and wheel speed can be selected for a given work material. The relationships between these variables and the costs are investigated.     

HD/SHD still image database system and image distribution in broadband network applications

This paper focuses on a practical design for an efficient scalable image database and retrieval system over broadband networks. It describes a concrete solution for the implementation of HD/SHD (high-definition/super-high-definition) still image retrieval services which can be used in different applications. The structure of the complete system, consisting of a directory server, an image server, and MMI (man-machine interface) devices, has been presented, detailing each element and their corresponding functions. The desired HD/SHD image is displayed on the HD-PDP (plasma display panel) with the aid of image matching. The proposed system generates image index automatically, eliminating special skills in preparing index images and crucially reducing the processing time (from 35 min to 110 s), and does not use keywords. It has been also shown that these indices can be used for quite accurate image retrieval, i.e., the system provides high precision rates (currently up to 98%) to the user, eliminating troubles encountered in the image retrieval operations due to limitation on the user’s age, culture, knowledge, and languages.The broadband IP networks currently have a number of issues from the viewpoint of practical system operations, and so the requirements and issues needed for the networks are discussed from the viewpoint of in-service performance, differentiation among different types of services, secure connections, and so on, focusing on handling of HD/SHD still images.     

Development of a pulse control-type MEMS microrobot with a hardware neural network

This article presents the micro-electro-mechanical systems (MEMS) microrobot which demonstrates locomotion controlled by hardware neural networks (HNN). The size of the microrobot fabricated by the MEMS technology is 4 × 4 × 3.5 mm. The frame of the robot is made of silicon wafer, and it is equipped with a rotary-type actuator, a link mechanism, and six legs. The rotary-type actuator generates rotational movement by applying an electrical current to artificial muscle wires. The locomotion of the microrobot is obtained by the rotation of the rotary-type actuator. As in a living organism, the HNN realized robot control without using any software programs, A/D converters, or additional driving circuits. A central pattern generator (CPG) model was implemented as an HNN system to emulate the locomotion pattern. The MEMS microrobot emulated the locomotion method and the neural networks of an insect with the rotary-type actuator, the link mechanism, and the HNN. The microrobot performed forward and backward locomotion, and also changed direction by inputting an external trigger pulse. The locomotion speed was 0.325 mm/s and the step width was 1.3 mm.     

Replica Exchange Light Transport

We solve the light transport problem by introducing a novel unbiased Monte Carlo algorithm called replica exchange light transport, inspired by the replica exchange Monte Carlo method in the fields of computational physics and statistical information processing. The replica exchange Monte Carlo method is a sampling technique whose operation resembles simulated annealing in optimization algorithms using a set of sampling distributions. We apply it to the solution of light transport integration by extending the probability density function of an integrand of the integration to a set of distributions. That set of distributions is composed of combinations of the path densities of different path generation types: uniform distributions in the integral domain, explicit and implicit paths in light (particle/photon) tracing, indirect paths in bidirectional path tracing, explicit and implicit paths in path tracing, and implicit caustics paths seen through specular surfaces including the delta function in path tracing. The replica‐exchange light transport algorithm generates a sequence of path samples from each distribution and samples the simultaneous distribution of those distributions as a stationary distribution by using the Markov chain Monte Carlo method. Then the algorithm combines the obtained path samples from each distribution using multiple importance sampling. We compare the images generated with our algorithm to those generated with bidirectional path tracing and Metropolis light transport based on the primary sample space. Our proposing algorithm has better convergence property than bidirectional path tracing and the Metropolis light transport, and it is easy to implement by extending the Metropolis light transport.     

Multi-contact vertical ladder climbing with an HRP-2 humanoid

We describe the research and the integration methods we developed to make the HRP-2 humanoid robot climb vertical industrial-norm ladders. We use our multi-contact planner and multi-objective closed-loop control formulated as a QP (quadratic program). First, a set of contacts to climb the ladder is planned off-line (automatically or by the user). These contacts are provided as an input for a finite state machine. The latter builds supplementary tasks that account for geometric uncertainties and specific grasps procedures to be added to the QP controller. The latter provides instant desired states in terms of joint accelerations and contact forces to be tracked by the embedded low-level motor controllers. Our trials revealed that hardware changes are necessary, and parts of software must be made more robust. Yet, we confirmed that HRP-2 has the kinematic and power capabilities to climb real industrial ladders, such as those found in nuclear power plants and large scale manufacturing factories (e.g. aircraft, shipyard) and construction sites.     

Locomotion Control of MEMS Microrobot Using Pulse‐Type Hardware Neural Networks

This paper presents the locomotion control of a microelectromechanical system (MEMS) microrobot. The MEMS microrobot demonstrates locomotion control by pulse‐type hardware neural networks (P‐HNN). P‐HNN generate oscillatory patterns of electrical activity like those of living organisms. The basic component of P‐HNN is a pulse‐type hardware neuron model (P‐HNM). The P‐HNM has the same basic features as biological neurons, such as the threshold, the refractory period, and spatiotemporal summation characteristics, and allows the generation of continuous action potentials. P‐HNN has been constructed with MOSFETs and can be integrated by CMOS technology. Like living organisms, P‐HNN has realized robot control without using software programs or A/D converters. The size of the microrobot fabricated by MEMS technology was 4 × 4 × 3.5 mm. The frame of the robot was made of a silicon wafer, equipped with rotary actuators, link mechanisms, and six legs. The MEMS microrobot emulated the locomotion method and the neural networks of an insect by rotary actuators, link mechanisms, and the P‐HNN. We show that the P‐HNN can control the forward and backward locomotion of the fabricated MEMS microrobot, and that it is possible to switch its direction by inputting an external trigger pulse. The locomotion speed was 19.5 mm/min and the step size was 1.3 mm. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(3): 43–50, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22473     

Mechanochemical solid-phase reaction between polyvinylidene fluoride and sodium hydroxide

Grinding a mixture of polyvinylidene fluoride (PVDF) and NaOH was conducted by a planetary ball mill at atmospheric condition to investigate mechanochemical reaction between the two substances. The grinding stimulates the reaction to form NaF and organic composites. Yield of fluorine converted from PVDF to NaF increases with an increase in grinding time and reaches 90% at 60 min or more. As for the organic phase, oxygen-bearing compounds are formed due to substitution of fluorine by OH base. The organic compounds are classified into water-soluble and insoluble ones, depending on their structures. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2249–2252, 2001     

Correlations of Hepatic Hemodynamics,Liver Function,and Fibrosis Markers in Nonalcoholic Fatty Liver Disease: Comparison with Chronic Hepatitis Related to Hepatitis C Virus

The progression of chronic liver disease differs by etiology. The aim of this study was to elucidate the difference in disease progression between chronic hepatitis C (CHC) and nonalcoholic fatty liver disease (NAFLD) by means of fibrosis markers, liver function, and hepatic tissue blood flow (TBF). Xenon computed tomography (Xe-CT) was performed in 139 patients with NAFLD and 152 patients with CHC (including liver cirrhosis (LC)). The cutoff values for fibrosis markers were compared between NAFLD and CHC, and correlations between hepatic TBF and liver function tests were examined at each fibrosis stage. The cutoff values for detection of the advanced fibrosis stage were lower in NAFLD than in CHC. Although portal venous TBF (PVTBF) correlated with liver function tests, PVTBF in initial LC caused by nonalcoholic steatohepatitis (NASH-LC) was significantly lower than that in hepatitis C virus (C-LC) (p = 0.014). Conversely, the liver function tests in NASH-LC were higher than those in C-LC (p < 0.05). It is important to recognize the difference between NAFLD and CHC. We concluded that changes in hepatic blood flow occurred during the earliest stage of hepatic fibrosis in patients with NAFLD; therefore, patients with NAFLD need to be followed carefully.     

Durability of radiation-sterilized polymers III. Oxidation layer determined by chemiluminescence

Chemiluminescence (CL) analysis was used for determining the oxidation layer formed by the irradiation of polypropylene for medical supplies. The depth of the oxidation layer from the surface depended on dose rate and increased with decreasing dose rate. The oxidation occurred remarkably at a region near the surface area of the film where the diffusion of oxygen is more sufficient. On the contrary, there was very little oxidation in the interior portion. The oxidation layers of polypropylene samples irradiated with electron beam showed U-shaped profiles in the cross-section of film as did as a sample irradiated with γ-rays. However, the degree of oxidation by irradiation with electron beam was very small; CL intensity at the surface area was only one-third that for the γ-irradiated samples.     

Degradability testing of radiation-vulcanized natural rubber latex films

The degradability under various conditions of five kinds of radiation-vulcanized natural rubber latex (RVNRL) films was studied. The treatments were leaching in methanol, leaching in 1% ammonia solution, mixing with tris(nonylated phenyl)phosphite (TNP) antioxidant, blending with poly(methyl methacrylate) (PMMA), and grafting with PMMA, Comparisons were made with sulfur-vulcanized natural rubber latex (SVNRL) film. RVNRL films SVNRL film can be kept for a long time when indirectly exposed to sunlight at room temperature. However, the former degraded much more rapidly than did the latter. TNP was found to be very suitable as an antioxidant to prolong the life of RVNRL films under dry conditions. PMMA, either blended or grafted with RVNRL, was ineffective in the prevention of deterioration of RVNRL films. The rapid degradation of RVNRL products could be an advantage over SVNRL products in environmental and wildlife conservation. © 1994 John Wiley & Sons, Inc.