We propose the kernel-based pattern recognition hardware and its design methodology using the genetic algorithm. In the proposed design methodology, pattern data are transformed into the truth tables and the truth tables are evolved to represent kernels in the discrimination functions for pattern recognition. The evolved truth tables are then synthesized to logic circuits. Because of this data direct implementation approach, no floating point numerical circuits are required and the intrinsic parallelism in the pattern data set is embedded into the circuits. Consequently, high speed recognition systems can be realized with acceptable small circuit size. We have applied this methodology to the image recognition and the sonar spectrum recognition tasks, and implemented them onto the newly developed FPGA-based reconfigurable pattern recognition board. The developed system demonstrates higher recognition accuracy and much faster processing speed than the conventional approaches.

A performance comparison between TCP and UDP in PHS Internet access is made by experiment from a media synchronization point of view. We consider a situation where PHS mobile terminals access H. 263 video and G. 726 audio stored at a media server by a streaming method. PIAFS is adopted as the data link protocol for the PHS wireless channels. We examined how white noise and Rayleigh fading on the PHS channel as well as the Internet traffic affect the performance. For the comparison, we evaluated several performance measures such as the coefficient of variation of output interval, and found that UDP outperforms TCP in almost all cases.

High integration and low power operation of integrated circuits make noise sensitivity high. Therefore, it is important to reduce noise of circuits. A bias-offset transconductor is known as a linear transconductor. It is expected that noise sensitivity of the transconductor becomes higher due to improvement of linearity and reduction of power dissipation. This paper proposes a design method to reduce noise considering high linearity, reduction of power dissipation and small circuit size.

We review the recent advances on strain and temperature sensing techniques based on multimodal interference in perfluorinated (PF) graded-index (GI) polymer optical fibers (POFs). First, we investigate their fundamental characteristics at 1300nm. When the core diameter is 62.5µm, we obtain strain and temperature sensitivities of -112pm/µε and +49.8nm/°C, the absolute values of which are, by simple calculation, approximately 13 and over 1800 times as large as those in silica GI multimode fibers, respectively. These ultra-high strain and temperature sensitivities probably originate from the unique PF polymer used as core material. Subsequently, we show that the temperature sensitivity (absolute value) is significantly enhanced with increasing temperature toward ∼70°C, which is close to the glass-transition temperature of the core polymer. When the core diameter is 62.5µm, the sensitivity at 72°C at 1300nm is 202nm/°C, which is approximately 26 times the value obtained at room temperature and >7000 times the highest value previously reported using a silica multimode fiber. Then, we develop a single-end-access configuration of this strain and temperature sensing system, which enhances the degree of freedom in embedding the sensors into structures. The light Fresnel-reflected at the distal open end of the POF is exploited. The obtained strain and temperature sensitivities are shown to be comparable to those in two-end-access configurations. Finally, we discuss the future prospects and give concluding remarks.

Low-profile inverter power supplies are increasingly required for backlight systems of liquid crystal displays (LCDs). A great deal of attention has been focused on the application of piezoelectric transformers (PTs) to such power supplies. To miniaturize PT inverters still further, PTs need to have sufficient high voltage-step-up-ratio, which can be achieved by a multilayered PT. First, this paper describes a method for simulating such performance using a distributed constant equivalent circuit model. The results of the simulation for a multilayered PT operated in the third order longitudinal vibration mode show that the resistance of internal electrodes causes the dominant loss factor. Next, a power inverter incorporating the multilayered PT was fabricated. This power inverter can be operated over a wide input DC voltage range from 7-20 V. Regarding a conventional inverter drive circuit, when input DC voltage range was extended, the inverter efficiency remarkably decreased. For the reason, we developed a new inverter circuit, which is equipped with an automatic drive voltage control circuit to maintain the drive voltage to the PT at a constant value. As a result, the fabricated power inverter exhibited more than 90% overall efficiency and 3.5 W output power, which is enough to light up a 12.1-inch color LCD. The maximum luminance efficiency on a light transmission plate of the backlight was as high as 30 cd/m2/W.

For measuring high frequency ultrasonic fields which are often spatially distributed and transient, an array probe with small element sensors is highly required. In this paper, we propose a fiber-optic micro-probe array which is based on wavelength-division-multiplexing technique. The element sensor consists of a micro optical cavity of 100 µm long made at the end of optical fiber. Optical path length of the cavity is changed by the applied acoustic field, and the modulation of output light intensity is monitored at another end of the fiber for the information of the acoustic field. Array of sensor elements and a light source as well as a photo detector are connected together by an optical star coupler. The Fabry-Perot resonance wavelength of each sensor element is designed different one another, and the outputs from the sensors are discriminated by sweeping the wavelength of light source with the use of a tunable semiconductor laser. In this paper, the performance of the micro-probe array is discussed experimentally.

A full-wave analysis of antennas with polarization grids is performed. Radiation patterns of antennas for two types of grids (straight strip and curved strip) are presented, where effects of the grid position and the grid paramenters are discussed.