Hitoshi KIYA Hiroyuki KOBAYASHI Osamu WATANABE
This paper discusses a method of designing linear phase two-channel filter banks for integer wavelet transform. We show that the designed filter banks are easily structed as the lifting form by leading relationship between designed filters and lifting structure. The designed integer wavelets are applied to image compression to verify the efficiency of our method.
In this paper, we propose a function that provides scalability of image quality on the basis of regions of interest for JPEG2000 coding. Functions of this type are useful in the progressive transmission of images, where the aim is to more quickly decode regions of interest than backgrounds. The conventional methods of progressive transmission have mainly been based on SNR scalability or on resolution scalability. With these conventional functions, it is impossible to achieve region-based scalability in the progressive transmission of images. The proposed methods use the ROI and SNR layer structures of JPEG2000, so the methods are suitable for the region-progressive transmission of JPEG2000 images.
We investigate the relationship between two different notions of reducibility among prediction (learning) problems within the distribution-free learning model of Valiant (PAC learning model). The notions of reducibility we consider are the analogues for prediction problems of the many-one reducibility and of the Turing reducibility. The former is the notion of prediction preserving reducibility developed by Pitt and Warmuth, and its generalization. Concerning these two notions of reducibility, we show that there exist a pair of prediction problems A and B, whose membership problems are polynomial time solvable, such that A is reducible to B with respect to the Turing reducibility, but not with respect to the prediction preserving reducibility. We show this result by making use of the notion of a class of polynomially sparse variants of a concept representation class. We first show that any class A of polynomially sparse variants of another class B is reducible to B with respect to the Turing reducibility'. We then prove the existence of a prediction problem R and a class R of polynomially sparse variants of R, such that R does not reduce to R with respect to the prediction preserving reducibility.
Hiroyuki KOBAYASHI Osamu WATANABE Hitoshi KIYA
We propose an efficient two-layer near-lossless coding method using an extended histogram packing technique with backward compatibility to the legacy JPEG standard. The JPEG XT, which is the international standard to compress HDR images, adopts a two-layer coding method for backward compatibility to the legacy JPEG standard. However, there are two problems with this two-layer coding method. One is that it does not exhibit better near-lossless performance than other methods for HDR image compression with single-layer structure. The other problem is that the determining the appropriate values of the coding parameters may be required for each input image to achieve good compression performance of near-lossless compression with the two-layer coding method of the JPEG XT. To solve these problems, we focus on a histogram-packing technique that takes into account the histogram sparseness of HDR images. We used zero-skip quantization, which is an extension of the histogram-packing technique proposed for lossless coding, for implementing the proposed near-lossless coding method. The experimental results indicate that the proposed method exhibits not only a better near-lossless compression performance than that of the two-layer coding method of the JPEG XT, but also there are no issue regarding the combination of parameter values without losing backward compatibility to the JPEG standard.
Toshiya MITOMO Osamu WATANABE Ryuichi FUJIMOTO Shunji KAWAGUCHI
A quadrature demodulator (QDEMOD) for WCDMA direct-conversion receiver using a common-base input stage is reported. A common-base input stage is robust to parasitic elements and is suitable for integrating on-chip matching circuits to realize small and low-cost RF front-end modules. However, a common-mode blocker signal, such as the transmitter (TX) leakage signal, degrades the noise performance due to DC current increase and intermodulation distortion of the TX leakage signal and noise. We propose a QDEMOD with a common-base input stage capable of suppressing the TX leakage signal using symmetrical inductors. The QDEMOD was fabricated using SiGe BiCMOS process with fT of 75 GHz. The measured results show that the NF degradation does not occur until the TX leakage signal input is larger than -10 dBm.
Tomonori ANDO Yoshiyuki KABASHIMA Hisanao TAKAHASHI Osamu WATANABE Masaki YAMAMOTO
We study nn random symmetric matrices whose entries above the diagonal are iid random variables each of which takes 1 with probability p and 0 with probability 1-p, for a given density parameter p=α/n for sufficiently large α. For a given such matrix A, we consider a matrix A ' that is obtained by removing some rows and corresponding columns with too many value 1 entries. Then for this A', we show that the largest eigenvalue is asymptotically close to α+1 and its eigenvector is almost parallel to all one vector (1,...,1).
Ryuichi FUJIMOTO Osamu WATANABE Fumie FUJII Hideyuki KAWAKITA Hiroshi TANIMOTO
Simple and scalable device-modeling techniques for inductors and capacitors are described. All model parameters are calculated from geometric parameters of the device, process parameters of the technology, and a substrate resistance parameter. Modeling techniques for other devices, such as resistors, varactor diodes, pads and MOSFETs, are also described. Some simulation results using the proposed device-modeling techniques are compared with measured results and they indicate adequacy of the proposed device-modeling techniques.