A content search system considering the activity and context of a mobile user

People routinely carry mobile devices in their daily lives and obtain a variety of information from the Internet in many different situations. In searching for information (content) with a mobile device, a user’s activity (e.g., moving or stationary) and context (e.g., commuting in the morning or going downtown in the evening) often change, and such changes can affect the user’s degree of concentration on his or her mobile device’s display and information needs. Therefore, a search system should provide the user with an amount of information suitable for the current activity and a type of information suitable for the current context. In this study, we present the design and implementation of a content search system that considers a mobile user’s activity and context, with the goal of reducing the user’s operation load for content search. The proposed system switches between two kinds of content search systems according to the user’s activity: the location-based content search system is activated when the user is stationary (e.g., standing and sitting), while a menu-based content search system is activated when the user is moving (e.g., walking). Both systems present information according to user context. The location-based system presents detailed information via menus and a map according to location-based categories. The menu-based system presents only a few options to enable users to get content easily. Through user experiments, we confirmed that participants could get desired information more easily with this system than with a commercial search system.     

PLANGENT: an approach to making mobile agents intelligent

Network environments give computer users the option of employing distributed information and services to complete a task. However, gathering information and using services distributed in networks requires knowing exactly what kinds of information and services are required for a task, where they are, and how they can be obtained or utilized. Tracking down the answers to these questions can be difficult, time consuming tasks for users. Mobile agent technology is expected to release them from having to do so. Instead, “intelligent” mobile agents will comprehend the user's requirements, search network nodes autonomously for appropriate information and services, and return with the answers. But several problems must be solved before we can expect agents to perform such actions effectively. We focus on the question of intelligence as a prerequisite for agent functions. What sort of intelligence is expected of agents? We have adopted a model based on the ability to make flexible plans. Specifically, we think mobile agents must be able to: understand user requirements; plan actions that will satisfy the requirements act according to the plan; modify the plan according to actual conditions when they differ from those initially expected; and execute the modified plan. We have implemented these functions in the Plangent system and validated their effectiveness in several example applications. We describe how we combined these planning functions with mobile agent facilities, and show how the agents behave intelligently in an example application of personal travel assistance     

Fabrication of X-rays mask with carbon membrane for diffraction gratings

We have produced diffraction gratings for obtaining high resolution X-ray phase imaging, such as X-ray Talbot interferometer. These diffraction gratings were required to have a fine, high accuracy, high aspect ratio structure. Therefore, we decided to use the X-rays lithography technique that used synchrotron radiation of the directivity for a manufacture process. The accuracy of the completed structure depends largely on the accuracy of the X-ray mask. In our group, a resin material is conventionally used for the membrane of large X-ray masks. However, X-ray masks comprising a resin membrane have the disadvantage that, after several cycles of X-ray exposure, they crease and sag due to X-ray-derived heat. As a substitute for the conventional resin membrane, we experimentally fabricated a new X-ray mask using a carbon wafer membrane. The newly fabricated X-ray mask was subjected to X-ray exposure experiment. We succeeded in making the structure body which was almost shape. And the experimental results verified that the new mask did not deteriorate even when used repeatedly, demonstrating that it was highly durable.     

Cylindrical coils created with 3D X-ray lithography and metallization

The demand for microactuators is increasing recently. The key technology to realizing practical microactuators is microfabrication process. In the production of microminiature components, the technologies for processing high-aspect-ratio structures are essential. As one of these technologies, the LIGA process is widely known. Our laboratory researches the LIGA process to three-dimensional microfabrication and established the cylindrical-microcoil production process. In this paper, we have fabricated the cylindrical-microcoil for the solenoidal electromagnetic type microactuator. We designed and analyzed microactuators, and fabricated and evaluated microactuator coils produced by the combination of three-dimensional X-ray lithography and level copper plating. We succeeded in creating threaded groove-shaped structures with 10 μm line width, 20 μm pitch, and aspect ratio of 5 on the surface of an acrylic pipe by means of three-dimensional X-ray lithography. As a measure to suppress void generation, which is one of the shortcomings of electrolytic plating processes, the sputtering apparatus and plating equipment were improved, a pretreatment process was additionally provided, and the actual electrolytic plating method was improved. As a result, a void-free metallic deposit could be formed on a thin coil line. The processing technology enables the formation of thin-wire coil lines whose current paths feature a large allowable current-carrying capacity, enabling the production of miniature, high-output microactuators.     

Modeling of the pharyngeal muscle in Caenorhabditis elegans based on FitzHugh-Nagumo equations

The pharyngeal pumping motion to send food to the bowel is a rhythmic movement in Caenorhabditis elegans. This paper proposes a simulation-based approach to investigate the mechanisms of rhythm phenomena in the pharyngeal pumping motion. To conduct the simulations, first, we developed a pharyngeal muscle model including 29 cell models which simulate the activity of each cell as a membrane potential based on FitzHugh-Nagumo equations. Then, to compare the response of the model with that of C. elegans, we calculated the electropharyngeogram (EPG), which represents the electrophysiological responses of the pharyngeal cells, using the simulated membrane potentials. The results confirmed that our model could generate the EPG similar to that measured from C. elegans. We proposed a computer simulation of the pumping motion to investigate the mechanisms of rhythm phenomena in living organisms.     

Microfabrication by hot embossing and injection molding at LASTI

LIGA process includes three processes as X-ray lithography, electroforming to fabricate metalic molds and replication, and can be fabricated nano and micro parts for various devices that it is difficult to product by conventional machining methods. A key technology which gathers mass-production efficiency in the LIGA process is micro-replication technology. We choiced hot embossing and injection molding methods for replication. For a demonstration, two kinds of Ni molds, a mesh pattern within a line width of 100 m, and an aspect ratio of 1.0 and a mesh pattern within a line width of 40 m, and an aspect ratio of 2.5, were prepared. These were produced with X-ray lithography and nickel electrofoming technique. In hot embossing, an experiment of micro-replication using polymethyl methacrylate (PMMA) and polycarbonate (PC) sheets succeeded. At injection molding, it could not transfer well with PMMA and PC, but injection temperature was set up highly, and it succeeded by cycloolefin polymer. Furthermore, we measured sidewalls surface roughness of microstructures produced at each steppes of the LIGA process, and it checked that the LIGA process had processing accuracy higher than a conventional machining method.We would like to thank Ms. A. Kitajima and Dr. R. Maeda at National Institute of Advanced Industrial Science and Technology (AIST), Mr. M. Ohtomo at Ikegami Mold Engineering Co., Ltd., and Mr. Noriaki Sato at Juken Kogyo Co., Ltd. for their valuable collaboration and contributions. This research was the contract research from the New Industry Research Organization (NIRO) supported financially by the New Energy and Industrial Technology Development Organization (NEDO).     

Chemical vapour deposition of Si3N4 from a gas mixture of Si2Cl6, NH3 and H2

Si₃N₄ layers were obtained on a quartz substrate from a gas mixture of Si₂Cl₆, NH₃ and H₂ under a reduced pressure in a temperature range of 800 to 1300‡ C. Amorphous Si₃N₄ layers that were dense and adherent to the substrate were obtained in a temperature range of 800 to 1100‡ C. On the other hand,α-Si₃N₄ layers were obtained at 1200‡ C and a source-gas ratio (N/Si) of 1.33 to 1.77. The lowest deposition temperature of amorphous Si₃N₄ was considered to be about 700‡ C. The microhardness of amorphous Si₃N₄ obtained in a temperature range of 800 to 1100‡ C was 2400 to 2600 kg mm⁻² (load: 50 g), and that ofα-Si₃N₄ obtained at 1200‡ C was 3400 kg mm⁻². Chlorine contents in the Si₃N₄ layer decreased with increasing deposition temperature and source-gas ratio (N/Si), and with decreasing total pressure.     

Involvement of formate as an interspecies electron carrier in a syntrophic acetate-oxidizing anaerobic microorganism in coculture with methanogens

To determine whether formate is involved in interspecies electron transfer between substrate-oxidizing bacteria and hydrogenotrophic microorganisms under anaerobic conditions, a syntrophic acetate-oxidizing bacterium Thermacetogenium phaeum strain PB was cocultured either with a formate /H2-utilizing methanogen strain TM (designated as PB/TM coculture), or an H2-utilizing methanogen strain deltaH (designated as PB/deltaH coculture). Acetate oxidation and subsequent methanogenesis in PB/TM coculture were found to be significantly faster than in PB/deltaH coculture. Formate dehydrogenase and hydrogenase were both detected in strains PB and TM. H2 partial pressures in the PB/TM coculture were kept lower (20 to 40 Pa) than those of the PB/deltaH coculture (40 to 60 Pa) during the exponential growth phase. Formate was also detected in both PB/TM and PB/deltaH cocultures, and the concentration of formate was maintained at a lower level in the PB/TM coculture (5 to 9 microM) than in the PB/deltaH coculture. Thermodynamic calculations revealed that the concentrations of both H2 and formate severely affect the syntrophic oxidation of acetate. These results strongly indicate that not only H2 but also formate may be involved in interspecies electron transfer.     

Emerging technology and service enhancement for cordless telephonesystems

A brief history of the development of cordless telephone systems in Japan is given. The efficient frequency utilization and upgraded service provided by this technology are discussed. A business cordless system is proposed for extended service areas using a portable telephone facility. The potential extension of this system to a local area portable telephone system is mentioned