Grasp and Delivery for Moving Objects on Broken Lines

This paper studies the following variant of the Vehicle Routing Problem that we call the Grasp and Delivery for Moving Objects (GDMO) problem, motivated by robot navigation: The input to the problem consists of n products, each of which moves on a predefined path with a fixed constant speed, and a robot arm of capacity one. In each round, the robot arm grasps one product and then delivers it to the depot. The goal of the problem is to find a collection of tours such that the robot arm grasps and delivers as many products as possible. In this paper we prove the following results: (i) If the products move on broken lines with at least one bend, then the GDMO is MAXSNP-hard, and (ii) it can be approximated with ratio 2. However, (iii) if we impose the “straight line without bend” restriction on the motion of every product, then the GDMO becomes tractable. Y. Asahiro’s research was supported in part by Grant-in-Aid for Young Scientists 15700021, and Research on Priority Areas 16092223. E. Miyano’s research was supported in part by Grant-in-Aid for Research on Priority Areas 16092223. Presently, S. Shimoirisa is with the Software Development Engineering Department, Products Development Center, Retail Information Systems Company, Toshiba TEC Corporation.     

DC interruption characteristic of vacuum circuit breaker

A high‐speed vacuum circuit breaker (HSVCB) has been investigated. HSVCB makes high‐frequency current superimposed on a fault current so that the current is forced to be zero and is interrupted. Its interruption performance is considered to be dependent on the rate of change of the current (di/dt). As a fundamental research, we investigated the di/dt– dv/dt characteristics and the insulation recovery characteristic after interrupting the counter‐pulse current for various contact materials of AgWC, CuW, and CuCr. The results revealed that the case where the gap length is larger is better in a current interruption performance. Moreover, it was found that di/dt is not dependent on the insulation recovery characteristics, but the magnitude of interruption current is of great influence. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(1): 17– 25, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20362     

Current reliability issues and future technologies for systems on silicon – processes, circuits, chip architecture, and design

The progress of silicon technology is opening the era of “systems on silicon” in which a large-scale memory, a CPU, and other logic macros will be integrated on a single chip. These kinds of chips, called system LSIs, have an especially promising future in mobile and multimedia applications but face inherent technical problems related to the reliability of ultrathin oxide film, conflict in the processing of different components, increased gate and subthreshold leakage currents, memory bottlenecks, and design complexity. This paper reviews the system LSIs and then introduces related technologies in processing, circuits, chip architecture, and design. It also discusses the influence of the system LSIs on business strategies.     

Antioxidant activity of Japanese pepper (Zanthoxylum piperitum DC.) fruit

Antioxidants were extracted from Japanese pepper (Zanthoxylum piperitum DC.) fruit and characterized. The antioxidant activity of the methanol extract from Japanese pepper fruit was found to be equal to that of α-tocopherol and stable under heat treatment. The main compounds that gave a significant antioxidant activity from the methanol extract were identified to be hyperoside (quercetin-3-O-galactoside) and quercitrin (quercetin-3-O-rhamnoside) as determined by HPLC, mass spectrometry, UV/Vis spectroscopy, and TLC. Radical-scavenging activities of hyperoside and quercitrin from Japanese pepper fruit were evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. As a result, hyperoside and quercitrin scavenged DPPH radical strongly with IC₅₀ values of 16 and 18 μM, respectively. These observations show the presence of strong antioxidants, namely hyperoside and quercitrin in Japanese pepper fruit.     

Origin of the Red Color of Satsuma Copper-Ruby Glass as Determined by EXAFS and Optical Absorption Spectroscopy

The origin of the ruby color of Satsuma glass, a famous copper-ruby glass produced in Japan in the mid-19th century, has been examined by electron microprobe analysis (EPMA), X-ray absorption fine structure (XAFS), and optical absorption spectroscopy analyses. Cu K XAFS analysis reveals that the major component of copper in the ruby glass consists of Cu(I) ions in the glass structure. This species is distinct from Cu₂O (cuprite), which we conclude is not responsible for the ruby color. Optical absorption spectra measured at 300 and 77 K clearly distinguishes the absorptions due to the colloidal particles of metallic copper and Cu₂O. It is concluded that the trace amount of copper in the ruby glass, which is below the detection limit of the EPMA and XAFS techniques, exists as metallic copper particles of nanometer size and is responsible for the ruby-red appearance of the Satsuma glass.     

Development of an indoor navigation system for a monocular-vision-based autonomous mobile robot

We have developed a technology for a robot that uses an indoor navigation system based on visual methods to provide the required autonomy. For robots to run autonomously, it is extremely important that they are able to recognize the surrounding environment and their current location. Because it was not necessary to use plural external world sensors, we built a navigation system in our test environment that reduced the burden of information processing mainly by using sight information from a monocular camera. In addition, we used only natural landmarks such as walls, because we assumed that the environment was a human one. In this article we discuss and explain two modules: a self-position recognition system and an obstacle recognition system. In both systems, the recognition is based on image processing of the sight information provided by the robot’s camera. In addition, in order to provide autonomy for the robot, we use an encoder and information from a two-dimensional space map given beforehand. Here, we explain the navigation system that integrates these two modules. We applied this system to a robot in an indoor environment and evaluated its performance, and in a discussion of our experimental results we consider the resulting problems.     

Sedimentation study on the binding of fibrinogen or of antithrombin III with acidic polysaccharides including heparin

Summary The binding of fibrinogen with heparin and dextran sulfates, and of antithrombin III with heparin and dextran sulfate were investigated by sedimentation velocity method. From the measurement of fibrinogen-acidic polysaccharide systems, it was confirmed that heparin and low molecular weight dextran sulfate(DSC) forms soluble complexes with fibrinogen, though the amount bound of the latter was rather small compared with high molecular weight dextran sulfate(DSD). Antithrombin III was also found to be bound by heparin and DSC. The numbers of heparin molecules bound to one molecule of fibrinogen and antithrombin III were estimated to be 4.2 and 0.3, respectively.     

Design of robotic behavior that imitates animal consciousness

A 6-degrees-of-freedom serial arm hand is controlled to move toward an object in an unseen environment. We developed a consciousness-based architecture (CBA), which is a hierarchical human development model representing the relationship between consciousness and behavior and is used for imitating a human groping action. During forward motion toward the object, a robot arm hand can help to avoid obstacles from which the robot collects contact information. The CBA organizes such information to learn a path plan for backward motion to the origin without contact with the obstacles. Experimental results show that the CBA successfully extends the hand to the goal while avoiding any obstacle. This work was presented in part at the 12th International Symposium on Artificial Life and Robotics, Oita, Japan, January 25–27, 2007     

Interfacial Electrical Properties of Nanodiamond Colloidal Species in Aqueous Medium as Examined by Acid-Base Indicator Dyes

This study was aimed at further examining of a detonated nanodiamond hydrosol, produced by the NanoCarbon Research Institute, Japan. In the concentrated solution, this colloidal system consists mainly of 3 nm-sized primary particles. These particles are positively charged and tend to associate into larger colloidal species on dilution. The species adsorb, first of all, the anionic dyes and readily coagulate on adding electrolytes. Some properties of the sol are changed during prolonged ageing but may be restored by adding small HCl amounts. Besides measuring the electrokinetic potential, the interfacial electrical potential was estimated by using acid-base indicators.