Toshikazu Kanaoka

Structured LDPC Codes With Reversed MTR/ECC for Magnetic Recording Channels

We propose a system for magnetic recording channels where we use a novel structured low-density parity-check (LDPC) code, called a random interleaved array (RIA) code, combined with a reversed maximum-transition run code/error-correction code. Simulation results show that the RIA code provides a significantly better error-rate floor performance than the conventionally structured LDPC code when applied to perpendicular magnetic recording channels. They also show that the system can achieve a 1.2-dB gain at a sector error rate of 10-5 compared with a PRML system combined with a high-rate run-length-limited code

Designing a Motivational Agent for Behavior Change in Physical Activity

People find behavior change particularly long-lasting change in habits regarding physical activity to be difficulty. While new technologies such as mobile applications that help individuals measure, log, and reflect on their activities hold great promise, they rely on individuals already having the motivation to change their behaviors. How can technology motivate people in increasing their level of physical activity? We explore this question through the design, development, and evaluation of an automated assistance system that draws on a counseling method called motivational interviewing (MI) and utilizes a humanlike robot as a motivational agent. Through dialogue and nonverbal engagement, the agent enables individuals to talk about and reflect on underlying reasons for their lack of motivation regarding physical activity in order to increase intrinsic motivation for behavior change. In this work-in-progress, we describe our system design and discuss findings from a preliminary study that evaluated the impact of the robots use of MI on user motivation and behavior.

Development of Signal Interpolated Phase Timing Recovery System for High Density Magneto-Optical Disks

We developed a new timing recovery system for magneto-optical disks (MO) with a higher recording density and higher transfer rate but it is difficult to achieve these without signal to noise ratio (SNR) degradation in the MO readout signal. Therefore, for signal processing, we have developed a turbo code technology, [rf1] which can obtain a high enough coding gain. However, as optimal phase to obtain the optimum performance of the turbo code must be detected, we developed a very precise phase timing recovery system that works under a degraded SNR in the MO readout signal. Moreover, as the turbo code is a kind of block code, which requires decoding by a turbo block unit, we also developed a system for detecting the start point for turbo decoding. We developed a new timing recovery system and, in this paper, we report architecture and performance evaluations of this system.

Read Channel with Turbo Decoding for Magneto-Optical Disks

Achieving high-density magneto-optical (MO) recording and a high transfer rate without degrading the signal-to-noise ratio (SNR) is not an easy task. Nonetheless, this is what we set out to do when we began developing a practical turbo decoding hardware description language (HDL) module for the MO read channel. To develop this module, we used a pipelined process to enable on-the-fly data reading, we optimized the system parameters, and we developed a time-sharing architecture to reduce the amount of required hardware. We tested the module using an HDL module simulator and an actual MO readout signal, and found that the SNR was improved by 3 dB compared to that required for partial response maximum likelihood (PRML) decoding.