Multiple fuzzy state-value functions for human evaluation through interactive trajectory planning of a partner robot

The purpose of this study is to develop partner robots that can obtain and accumulate human-friendly behaviors. To achieve this purpose, the entire architecture of the robot is designed, based on a concept of structured learning which emphasizes the importance of interactive learning of several modules through interaction with its environment. This paper deals with a trajectory planning method for generating hand-to-hand behaviors of a partner robot by using multiple fuzzy state-value functions, a self-organizing map, and an interactive genetic algorithm. A trajectory for the behavior is generated by an interactive genetic algorithm using human evaluation. In order to reduce human load, human evaluation is estimated by using the fuzzy state-value function. Furthermore, to cope with various situations, a self-organizing map is used for clustering a given task dependent on a human hand position. And then, a fuzzy state-value function is assigned to each output unit of the self-organizing map. The robot can easily obtain and accumulate human-friendly trajectories using a fuzzy state-value function and a knowledge database corresponding to the unit selected in the self-organizing map. Finally, multiple fuzzy state-value functions can estimate a human evaluation model for the hand-to-hand behaviors. Several experimental results show the effectiveness of the proposed method.     

Spatial indexing of high-dimensional data based on relative approximation

We propose a novel index structure, the A-tree (approximation tree), for similarity searches in high-dimensional data. The basic idea of the A-tree is the introduction of virtual bounding rectangles (VBRs) which contain and approximate MBRs or data objects. VBRs can be represented quite compactly and thus affect the tree configuration both quantitatively and qualitatively. First, since tree nodes can contain a large number of VBR entries, fanout becomes large, which increases search speed. More importantly, we have a free hand in arranging MBRs and VBRs in the tree nodes. Each A-tree node contains an MBR and its children VBRs. Therefore, by fetching an A-tree node, we can obtain information on the exact position of a parent MBR and the approximate position of its children. We have performed experiments using both synthetic and real data sets. For the real data sets, the A-tree outperforms the SR-tree and the VA-file in all dimensionalities up to 64 dimensions, which is the highest dimension in our experiments. Additionally, we propose a cost model for the A-tree. We verify the validity of the cost model for synthetic and real data sets. Edited by T. Sellis. Received: December 8, 2000 / Accepted: March 20, 2002 Published online: September 25, 2002     

Effects of4He coverage on the propagation of fourth sound in superfluid3He

We report measurements on the effects of⁴He coverage and pressure on the fourth sound propagation in superfluid³He in confined geometries of four different pore sizes.     

Ipidacrine (NIK-247), a novel antidementia, rapidly enters the brain and improves scopolamine-induced amnesia in rats during the Morris water maze task

The effects of single and repeated administrations of ipidacrine (NIK-247, 9-amino-2, 3, 5, 6, 7, 8-hexahydro-1H-cyclopenta [b] quinoline monohydrochloride monohydrate) on scopolamine-induced spatial learning deficit were investigated in rats using the Morris water maze task. A single oral administration of ipidacrine (0.3 and 1 mg/kg) reduced the increased total latency induced by scopolamine in this task. The repeated administration of ipidacrine (1 mg/kg) of once a day for 5 successive days reduced the increased total latency induced by scopolamine to the levels of the saline-treated control rats in this task. In this pharmaco-kinetic study, ipidacrine was rapidly taken up into the brain within 5 min. Moreover, higher drug levels were observed mainly in the cortex and hippocampus, which both play important roles in learning and memory. Thus, a previous study together with this investigation indicate that ipidacrine improves amnesia which consists of the impairment of the working and reference memory in various animal models, suggesting that ipidacrine is a useful candidate for the therapy of patients with Alzheimer's disease.     

Analysis of the spectral linewidth of distributed feedback laser diodes

The spectral linewidth of DFB laser diodes is analysed. DFB lasers with long cavities are shown to have very narrow spectral linewidth, and it is further narrowed if a phase shift is introduced at the centre of the cavities.     

Spin-Entropy Wave Propagation in 3He A1 in Magnetic Fields up to 12 Tesla

The propagation of spin-entropy wave has been studied in ³ He A ₁ in magnetic fields up to 12 tesla and at a pressure of 22.9 bar. The superfluid fraction at T _c2 extracted from the propagation velocity increases linearly with magnetic field and reduced temperature. The anomalous attenuation previously found near T _c2 in lower magnetic fields was also observed in the present maximum field. The pore size in the oscillating superleak transducer does not affect the anomalous attenuation. Outside the anomalous attenuation region, the dissipation coefficient is found to vary linearly with frequency. This frequency dependence is contrary to that of dissipations owing to viscous losses at walls and to bulk losses.     

PACVD-Beschichtung von Druckgußwerkzeugen unter ökonomischen und ökologischen Gesichtspunkten

Application of Wear Resistant PACVD-Coatings in Aluminium Diecasting under Economical and Ecological Aspects Aluminium pressure diecasting is a frequently applied manufacturing process for the near netshape production of precision parts. State of the art production techniques still demand considerable amounts of die lubricants. But the side effects of these lubricants include a decrease in surface quality of the cast part as well as a prolongation of the casting cycle time. The job quality decreases and the waste and exhaust disposal during production and application of lubricants is ecologically risky. In this study different wear resistant coating systems have been developed in order to minimize the use of die lubricants in the casting process while at the same time increasing the service life of the diecasting tools. Nitrides, carbides and borides of titanium were synthesized by means of DC-pulse-PACVD. The influence of the process parameters gas composition, pressure, voltage and pulse/pulse repetition ratio was investigated. Compositional analysis was performed by analytical methods such as XRD, EDS, WDS and SIMS. Hardness, adhesion and friction behaviour of the layers were determined in order to describe their mechanical properties. The wetting angle was determined and the corrosion resistance was evaluated in dip tests in aluminium melt. A selection of the best coatings was then compared in diecasting praxis tests under tightened-up conditions reducing the amount of lubricants. TiN, Ti(B,N), TiC and multilayers of the system Ti-C-N were deposited exhibiting a wide range of stoichiometry. The coatings reached hardness values of up to 4400 HK0.005 and the friction coefficient μ was in the range of 0.3. In the diecasting praxis test the amount of die lubricant could be reduced by 97%. Under most severe conditions all layer types led to a minimum increase in the lifetime of the tool of factor 60 compared to an untreated dummy. A strong dependence on the layer type and on its stoichiometry could be observed. Ti(B,N) as the most successful coating in this study has not yet shown any sign of failure and already achieved an increase in lifetime of 300 times.     

Velocity, electromechanical coupling factor and acoustic loss of surface shear waves propagating along x-axis on rotated Y-cut plates of LiNbO3

Velocity and propagation loss of surface shear waves are measured on free-space and metallised surfaces of LiNbO3 crystals along the x-axis of rotated Y-cut plates as a function of rotation about the x-axis between 35° and 70°. The coupling factor obtained from the velocities is 0.20 for a 35° rotated Y-cut plate and 0.09 for a 70° plate. The coupling factor changes linearly with the rotation angle. The propagation losses over the whole range measured here are less than 5 dB/cm on both free-space and on metallised surfaces. These losses are fairly low and very favourable for fabricating s.a.w. filters.     

Aneurysm of the great vein of Galen--report of a case (author's transl)

A case of aneurysm of the great vein of Galen was reported in which craniotomy and clipping of a feeding artery arising from the left posterior cerebral artery was successfully performed. This 5-month-old girl developed progressive hydrocephalus from 2 months after birth. At 5 months the head circumference was 50 cm with tense enlarged fontanelle. Both eye balls were deviated downward. The deep tendon reflexes were hyperactive with bilateral ankle clonus and positive Babinski's sign. Mild cardiomegaly and hepatomegaly were also noted. Cerebral angiograms showed a large aneurysm of the great vein of Galen fed by a single enlarged arterial branch from the left posterior cerebral artery. After the evaluation of systemic circulatory status and under strict control of fluid transfusion craniotomy was performed. The feeding artery was clipped at its entrance to the aneurysm via left parieto-occipital interhemispheric approach. A rise in the mean arterial blood pressure of 20 mmHg was observed immediately following clipping. The postoperative course was satisfactory except for a left subdural fluid collection which required subduro-peritoneal shunt. The aneurysm was completely disappeared on the postoperative angiograms and the child is regaining the normal development. This is the first case of aneurysm of the great vein of Galen successfully operated in Japan. Clinical symptoms and signs, radiological features and operative treatment of the disease were reviewed from a total of 46 cases reported in the world literature.     

Effect of partial shading on photoproduction of hydrogen by Chlorella

The photoproduction of hydrogen by the green alga Chlorella pyrenoidosa was studied in 650-ml bubble columns made of glass with 7 cm diameter. Hydrogen was produced by adding sodium dithionite as an oxygen scavenger directly to an algal suspension. When a part of the wall of the bubble column was shaded with a sheet of plastic film impervious to light, the production rate and total volume of hydrogen increased as compared to those in the columns without partial shading. This relationship between the hydrogen photoevolution rate and the proportion of lighted region is contrary to normal photochemical reactions. This phenomenon is considered to be related to the regulation by light of the activity of the enzymes and/or the photosynthetic electron transport systems, which was examined by measuring fluorescence induction curves of dark-adapted Chlorella cells and also the distribution of light intensity within the bubble column bioreactors.