The development of ad hoc networking is now being watched with keen interest, because it is a key technology for realizing ubiquitous networks and ubiquitous society. In Japan, on ad hoc network, much R&D and related works have been done and on going in academia, industries and governments. Test-bed based research is an important aspect of research on ad hoc networks. The performance of ad hoc networks in real-world situations typically depends on many complex phenomena. This paper introduces a few topics of test-bed based ad hoc network research activities in Japan.

An infrared (IR) transcutaneous remote control was designed for use in the totally implantable middle ear system. Considering the IR reflection, absorption and scattering effect of the skin, the required IR radiant intensity is calculated. After we have implemented the designed control, the transcutaneous operation experiment was carried out using a porcine skin.

Ultra Wideband (UWB) communication system utilizing impulse signals is attractive technique which can achieve high data rate with low complexity and low power consumption. In this impulse based UWB system, lots of different shaped pulses have been considered to represent more information bits per symbol. In order to detect these different shaped UWB signals at the receiver, the synthesized template generation method using several elementary waveforms is effective. In this paper we design and analyze this synthesized template waveform instead of the conventional matched filter technique. The synthesis of UWB template waveform can be achieved as combinations of orthogonalized elementary waveforms with Fourier coefficients. By adjusting the number of elementary waveforms and their coefficients, it is possible to detect several types of UWB signals. The orders of approximation corresponding to different number of elementary waveforms are analyzed and the bit error rate properties are then investigated in AWGN and multipath fading channels. In addition, the proposed system can capture more energy by adjusting its coefficients adaptively under the multipath environment and reduce the effect of Intra-Pulse Interference (IPI) which is occurred when the propagation channel is not separable, that is, multipath components spaced closer than the typical pulse width. We show the design of the adaptive template synthesis method and its performance compared with conventional Rake receiver.

We demonstrate a novel fiber device exhibiting magnetic circular dichroism (MCD) and Faraday rotation in sharpened optical fibers coated with Fe. The degree of MCD was 0.68 in a magnetic field of 0.35 T and the Faraday rotation angle was as great as 110 degrees. Such great magneto-optical effect is due to optical near-field interactions in the sub-wavelength region, i.e., in the tip of the near-field fiber probe. These effects can be attributed to the large magnitude of the magneto optical coefficient of Fe.

The radiation properties of oscillating electric dipoles are studied theoretically for three and four layered systems including a single metallic slab based on angular spectrum representation of vector spherical waves. One of the remarkable results obtained is the transmission energy spectrum showing strong dependence on the thickness of a dielectric layer placed between oscillating electric dipole and metallic surface, which explains the experimental results of molecular fluorescence into surface plasmon modes. The theory based on angular spectrum representation and tunneling current provides us with a clear identification of plasmonic excitation transfer, transmission loss associated with plasmon transport in metallic layer, and energy dissipation or quenching of excitation due to surface plasmon excitation at the metallic surface in relation to the characteristic complex wave number of evanescent waves.

A timing-driven placement algorithm based on path topology analysis is presented. The optimization for path delay is transformed into cell location optimization. The algorithm pays much attention on path topologies and applies an effective force directed method to find cell target locations. Total wire length optimization is combined with the timing-driven placement algorithm. MCNC (Microelectronics Centre of North-Carolina) standard cell benchmarks are experimented and results show that our timing-driven placement algorithm can make the longest path delay improve up to 13% compared with wirelength driven placement.

JPEG2000 image compression standard is designed to cater the needs of a large span of applications including numerous consumer products. However, its use is restricted due to the high hardware cost involved in its implementation. Bit Plane Coder (BPC) is the main resource intensive component of JPEG2000. Its throughput plays a key role in deciding the overall throughput of a JPEG2000 encoder. In this paper we present the algorithm and parallel pipelined VLSI architecture for BPC which processes a complete stripe-column concurrently during every pass. The hardware requirements and the critical path delay of the proposed technique are compared with the existing solutions. The experimental results show that the proposed architecture has 2.6 times greater throughput than existing architectures, with a comparatively small increase in hardware cost.

The electromagnetic field (EMF) distributions created inside a train carriage by the cellular radios of the passengers are analyzed and the impact their electromagnetic interference (EMI) on the implantable cardiac pacemakers is evaluated based upon the analysis results. Both computer simulations and experiments using 800 MHz and 2 GHz transmitters in an actual train carriage confirm that excessively high EMF, high enough to affect the normal functions of the pacemaker, does not occur inside the carriage provided the safe distance of 22 cm specified for pacemaker users is kept. A simplified histogram estimation method for electric field strength is newly developed to deal with the complicated EMF distributions. It allows the EMI risk to pacemakers by cellular radio transmission to be quantitatively evaluated. Methodologies are described first. Typical results of FDTD analysis and actual measurement data are then shown. Finally, considerations and conclusions are made.

This paper proposes the test phantom for the cochlear implant to estimate electromagnetic interference (EMI) from a cellular phone. This test phantom is constructed from a square tank filled with saline solution. The use of a flat phantom provides a level of consistency in duplicating the exposure conditions in the EMI tests. The measurement and calculation results show that there is no difference in the E-field strength near the surface of the phantom when comparing flat and head-shaped phantoms and that the flat phantom is sufficiently thick to disregard the influence of reflective waves near the surface of the phantom. The calculation results also indicate the appropriateness of using physiological saline (0.18 g/l) up to 3 GHz when comparing the E-field strength inside a phantom comprising physiological saline and in a 2/3 muscle model. The results of actual EMI testing of a cochlear implant show that there is no difference in the maximum interference distance when using either the flat or head-shaped phantom. Based on these results, this paper presents the validity of using the flat phantom in EMI tests from cellular phone for the cochlear implant.

Recently, Lin, Hwang, and Li proposed an efficient remote authentication scheme using smart cards for multi-server architecture based on the geometric property of the Euclidean plane. Herein, we show that their scheme is vulnerable to two forgery attacks and a password-guessing attack, and is not easily repairable. Furthermore, their scheme lacks a proper user eviction mechanism.

The increasing number of channels in dense wavelength division multiplexing (DWDM) systems has led to the need for wiring involving a large number of optical fibers in the system racks. We have developed a novel scalable optical fiber wiring system designed to realize as many as 10,000-fiber shuffled interconnections without fiber congestion. We propose a scheme for constructing a large-scale shuffler capable of permuting interconnected fibers that employs plural optical fiber sheets, and for arranging optical fibers without congestion in racks. We constructed a 16,384-fiber shuffler system with sixty-four 256-fiber shuffler sheets and 16-fiber fiber physical contact (FPC) connectors for a 128128 switch system with 1128 planar lightwave circuit (PLC) type thermo-optic switches (TOSW). Input here the part of summary.

Two types of miniaturized high-temperature superconducting filters are described in this paper. The first type is developed by using small-sized microstrip spiral resonators, and the second type by coplanar waveguide quarter-wavelength resonators. The filters have significantly reduced size compared with many previous HTS filters. They are designed by employing an electromagnetic simulator in combination with appropriately chosen equivalent circuits. Their measured frequency responses agree well with theoretical predictions, and show low insertion losses in spite of their small sizes.

This paper discusses how to minimize the number of dissection lines regarded as wiring channels on a floorplan corresponding to a placement of n modules. In a floorplan (rectangular dissection), the number of dissection lines exceeds the number of rooms exactly by three. Since a floorplan obtained from a given module placement may have many empty rooms where no module is assigned, redundant wiring channels and wire bends may also be generated. Hence, in order to reduce redundant channels and wire bends, removal of empty rooms is required. For this purpose, we formulate a problem of obtaining a floorplan with the minimum possible empty rooms based on a given module placement. Then, we propose a method of removing as many redundant empty rooms as possible by merging dissection lines on a floorplan in O(n) time. The number of empty rooms in the resultant floorplan is reduced to n- or less.

In order to reduce the size of a wireless system, we propose a design theory for the broadband impedance matching circuit which connects an electrically small antenna (ESA) to a semiconductor amplifier. We confirmed its validity for the case of connection between a small slot loop antenna with a small radiation resistance of Ra =0.776 Ω and a semiconductor amplifier with high input impedance of ZL =321-j871 Ω with the aid of the simulations by the electrical circuits using transmission lines as well as the electromagnetic field (EM field) simulator. We also made experiments on this antenna with matching circuits using high temperature superconductor YBCO thin films on MgO substrates.

In recent years, the Internet has come to be able to be used at higher speed and more cheaply everywhere as the broadband service and the wireless LAN service have been provided by various ISPs. In such a ubiquitous environment, a demand for mobile computing environments in the intranet and easy access from remote sites has been increasing greatly as well as the Internet. To meet this requirement, we have proposed a Logical Office service, which is a kind of the mobile VLAN, and enables terminal plug and play, layer two tunneling, and ubiquitous communication. This paper newly proposes that the offer of the IP mobility to not only the movement of the terminal but also existing network services be possible the Logical Office service which we developed. As a result, it was verified to operate existing network services such as wirelesses LAN on the Logical Office service, and for newly existing network services to able to have the IP mobility.

We present a low-phase-noise and frequency-tunable photonic millimeter-wave (MMW) generator based on two-mode beating. The generator consists of a single-mode laser, an external optical intensity modulator, and a planar lightwave circuit (PLC) on which an arrayed-waveguide grating (AWG) and 3-dB optical combiners are integrated. Because the AWG and the optical combiners are connected with optical waveguides and the optical path length difference between the two modes filtered by the AWG is kept constant, the phase fluctuation of the generated MMW signal is suppressed. The generator can generate MMWs with a phase noise of less than -75 dBc/Hz at 100 Hz and has a frequency tunability in a range of 90 to 125 GHz. The generator can be applied for the local oscillator (LO) in 10-Gbit/s wireless links that use heterodyne detection.

In the paper, we introduce TLM methodology focusing on IEEE 802.11 WLAN as a derivative system. Decomposing the entire system into several computation components, we analyzed the property of each transaction, resulting in the TLM. In the case of shared bus, the simulation results show the effect of communication architecture such as bus protocol and bus parameters on the system performance.

The three beam-switched top-loaded antenna is suited to be applied to a wireless local area network to switch the radiation pattern by arranging several unidirectional antennas. In this paper, a three beam switched top loaded monopole antenna is proposed to realize its small size and planar structure. Three top loaded monopole antennas are arranged around a parasitic hexagonal patch at intervals of 120 degrees. The feed element is selected by the switching device to switch the radiation pattern. This antenna allows for reduction in the number of elements as well as downsizing. The front to back ratio (F/B) becomes 23 dB by selecting suitable parameters.

In this paper we show that an outerplanar graph G with maximum degree at most 3 has a 2-D orthogonal drawing with no bends if and only if G contains no triangles. We also show that an outerplanar graph G with maximum degree at most 6 has a 3-D orthogonal drawing with no bends if and only if G contains no triangles.

Investment planning for power plants involves making a long-term plan covering various facility investments, such as the construction of a new power plant or the replacement of an old plant with a new one, under uncertain environments. In this paper, we propose an optimization method for such a planning problem. Our method is based on decision tree analysis, in which uncertain environments are described as scenarios. The maintenance of existing plants is also taken into account by introducing the option of large-scale repair in addition to replacement. In order to avoid combinatorial explosion of failure event scenarios of plants, we introduce the concept of failure risk cost which contributes to simplification of the decision tree and reduction of the calculation time.