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Nozomu TOGAWA Takashi SAKURAI Masao YANAGISAWA Tatsuo OHTSUKI
This letter proposes a hardware/software partitioning algorithm for digital signal processor cores with two register files. Given a compiled assembly code and a timing constraint of execution time, the proposed algorithm generates a processor core configuration with a new assembly code running on the generated processor core. The proposed algorithm considers two register files and determines the number of registers in each of register files. Moreover the algorithm considers two or more types of functional units for each arithmetic or logical operation and assigns functional units with small area to a processor core without causing performance penalty. A generated processor core will have small area compared with processor cores which have a single register file or those which consider only one type of functional units for each operation. The experimental results demonstrate the effectiveness and efficiency of the proposed algorithm.
Takehiro TAKAHASHI Hironori OKANIWA Takashi SAKUSABE Noboru SCHIBUYA
In this research, the performance degradation of the digital electronic equipment under electromagnetic (EM) disturbance was studied in order to investigate the interference of intra-equipment. To develop the evaluation method of the performance degradation, some communication indexes were measured under EM disturbance. From some experimental results, it is known that the performance degradation of the electronic equipment was estimated by the degradation of "through-put," one of the communication performance indexes. For further investigation of the interference of intra-equipment, the near EM field from a PCB of the electronic equipment and its performance degradation under EM disturbance were measured and compared. From the measured results, the relationship between near field measurement and performance degradation could be obtained in some extent. These facts enable us that the weak area under the EM disturbance application on PCB can be foreseen by measuring the near field emission from the equipment and vise versa.
Kazuaki SAWADA Hirokazu NAKAZAWA Shoko TAKENAGA Takeshi HIZAWA Masato FUTAGAWA Fumihiro DASAI Takashi SAKURAI Koichi OKUMURA Toshiaki HATTORI Makoto ISHIDA
To visualize the biochemical distribution two-dimensionally, we invented a solid-state-type ion image sensor that indicates the chemical activity of solutions and cells. The device, which consists of a CCD array covered with a functionalized membrane to detect charge accumulation, is highly sensitive to changes in the concentration and two-dimensional distribution of ions and biomaterials.
Takahiro IIZUKA Takashi SAKUDA Yasunori ORITSUKI Akihiro TANAKA Masataka MIYAKE Hideyuki KIKUCHIHARA Uwe FELDMANN Hans Jurgen MATTAUSCH Mitiko MIURA-MATTAUSCH
In LDMOS devices for high-voltage applications, there appears a notable fingerprint of current-voltage characteristics known as soft breakdown. Its mechanism is analyzed and modeled on LDMOS devices where a high resistive drift region exists. This analysis has revealed that the softness of breakdown, known as the expansion effect, withholding a run-away of current, is contributed by the flux of holes underneath the gate-overlap region originated by impact-ionization. The mechanism of the expansion effect is modeled and implemented into the compact model HiSIM_HV for circuit simulation. A good agreement between simulated characteristics and 2D-device simulation results is verified.
Teck Lin ANG Yuji TARUI Takashi SAKUSABE Takehiro TAKAHASHI Noboru SCHIBUYA
This paper describes a hybrid force-directed self-organizing neural network approach to printed circuit board (PCB) placement with consideration of electromagnetic compatibility (EMC). In most of the conventional PCB automatic placement algorithms, the only factor considered in the objective function is minimized total net length. However, for today's high speed and high density PCB, EMC compliance cannot be met by such single objective. To tackle this problem, the presented algorithm takes EMC into consideration, besides component overlap and minimized total net length. These factors are optimized by means of an adapted self-organizing map. Comparison of simulated placement results as well as actual measurements with commercial softwares confirms the effectiveness of the proposed method.
Mustafa M. SAMI Masahisa SAITO Shogo MURAMATSU Hisakazu KIKUCHI Takashi SAKU
We have developed a new computer-aided diagnostic system for differentiating oral borderline malignancies in hematoxylin-eosin stained microscopic images. Epithelial dysplasia and carcinoma in-situ (CIS) of oral mucosa are two different borderline grades similar to each other, and it is difficult to distinguish between them. A new image processing and analysis method has been applied to a variety of histopathological features and shows the possibility for differentiating the oral cancer borderline grades automatically. The method is based on comparing the drop-shape similarity level in a particular manually selected pair of neighboring rete ridges. It was found that the considered similarity level in dysplasia was higher than those in epithelial CIS, of which pathological diagnoses were conventionally made by pathologists. The developed image processing method showed a good promise for the computer-aided pathological assessment of oral borderline malignancy differentiation in clinical practice.