1-9hit |
Jianzhang CHEN Jianping LI Yuanyuan HUANG
Nonprimitive non-narrow-sense BCH codes have been studied by many scholars. In this paper, we utilize nonprimitive non-narrow-sense BCH codes to construct a family of asymmetric quantum codes and two families of quantum convolutional codes. Most quantum codes constructed in this paper are different from the ones in the literature. Moreover, some quantum codes constructed in this paper have good parameters compared with the ones in the literature.
Nitin SINGHAL Jin Woo YOO Ho Yeol CHOI In Kyu PARK
In this paper, we analyze the key factors underlying the implementation, evaluation, and optimization of image processing and computer vision algorithms on embedded GPU using OpenGL ES 2.0 shader model. First, we present the characteristics of the embedded GPU and its inherent advantage when compared to embedded CPU. Additionally, we propose techniques to achieve increased performance with optimized shader design. To show the effectiveness of the proposed techniques, we employ cartoon-style non-photorealistic rendering (NPR), speeded-up robust feature (SURF) detection, and stereo matching as our example algorithms. Performance is evaluated in terms of the execution time and speed-up achieved in comparison with the implementation on embedded CPU.
Le Trieu PHONG Kaoru KUROSAWA Wakaha OGATA
Undeniable signature, and unpretendable signature schemes have been studied independently. In this paper, efficient schemes which serve as both at the same time are presented. The schemes find their typical application in anonymous auction where the winner cannot deny her bid; nobody can pretend to be the winner; and the anonymity of all losers is preserved. The security of the schemes is proved in the common reference string model under discrete logarithm type assumptions.
We revisit the double-pipe construction introduced by Lucks at Asiacrypt 2005. Lucks originally studied the construction for iterated hash functions and showed that the approach is effective in improving security against various types of collision and (second-)preimage attacks. Instead, in this paper we apply the construction to the secret-key setting, where the underlying FIL (fixed-input-length) compression function is equipped with a dedicated key input. We make some adjustments to Lucks' original design so that now the new mode works with a single key and operates as a domain extension of MACs (message authentication codes). Though more than twice as slow as the Merkle-Damgård construction, the double-piped mode enjoys security strengthened beyond the birthday bound. More specifically, when iterating an FIL-MAC whose output size is n-bit, the new double-piped mode yields an AIL-(arbitrary-input-length-)MAC with security up to O(2n) query complexity. This bound contrasts sharply with the birthday bound of O(2n/2), which was the best MAC security accomplished by earlier constructions.
Landscapes have been the main theme in Chinese painting for over one thousand years. Chinese ink painting is a form of non-photorealistic rendering. Terrain is the major subject in Chinese landscape painting, and surface wrinkles are important in conveying the orientation of mountains and contributing to the atmosphere. Over the centuries, masters of Chinese landscape painting have developed various kinds of wrinkles. This work develops a set of novel methods for rendering wrinkles in Chinese landscape painting. A three-dimensional terrain is drawn as an outline and wrinkles, using information on the shape, shade and orientation of the terrain's polygonal surface. The major contribution of this work lies in the modeling and implementation of six major types of wrinkles on the surface of terrain, using traditional Chinese brush techniques. Users can select a style of wrinkle and input parameters to control the desired effect. The proposed method then completes the painting process automatically.
Koichi ICHIGE Masashi SHINAGAWA Hiroyuki ARAI
This paper studies on a fast approach for the eigenproblems of correlation matrices used in direction-of-arrival (DOA) estimation algorithms, especially for the case that the number of arriving waves is a few. The eigenvalues and the corresponding eigenvectors can be obtained in a very short time by the algebraic solvent of up to quartic polynomials. We also confirm that the present approach does not make the accuracy worse when it is implemented by finite word-length processors like digital signal processor (DSP) or field programmable gate array (FPGA).
Isao TAKENAKA Hidemasa TAKAHASHI Kazunori ASANO Kohji ISHIKURA Junko MORIKAWA Hiroaki TSUTSUI Masaaki KUZUHARA
This paper describes a high-power and low-distortion AlGaAs/GaAs HFET amplifier developed for digital cellular base station system. We proved experimentally that distortion characteristics such as IMD (Intermodulation Distortion) or NPR (Noise Power Ratio) are drastically degraded when the absolute value of the drain bias circuit impedance at low frequency are high. Based on the experimental results, we have designed the drain bias circuit not to influence the distortion characteristics. The developed amplifier employed two pairs of pre-matched GaAs chips mounted on a single package and the total output-power was combined in push-pull configuration with a microstrip balun circuit. The push-pull amplifier demonstrated state-of-the-art performance of 140 W output-power with 11.5 dB linear gain at 2.2 GHz. In addition, it exhibited extremely low distortion performance of less than 30 dBc at two-tone total output-power of 46 dBm. These results indicate that the design of the drain bias circuit is of great importance to achieve improved IMD characteristics while maintaining high power performance.
The double-stage threshold-type foreground-background congestion control for the common-store queueing system with multiple nonpreemptive priority classes is proposed to improve the transient performance, where the numbers of accepted priority packets in both foreground and background stores are controlled under the double-stage threshold-type scheduling. In the double-stage threshold-type congestion control, the background store is used for any priority packets, and some parts of the background store are reserved for lower-priority packets to accommodate more lower-priority packets in the background store, whereas some parts of the foreground store are reserved for higher-priority packets to avoid the priority deadlock. First, we derive the general set of coupled differential equations describing the system-state, and the expressions for mean system occupancy, throughput and loss probability. Second, the transient behavior of system performance is evaluated from the time-dependent state probabilities by using the Runge-Kutta procedure. It is shown that when the particular traffic class becomes overloaded, high throughputs and low loss probabilities of other priority classes can be obtained.
A queueing model suitable for multimedia packets with Poisson and batch Poisson arrivals is studied. In the queueing model, priority is given to the packets with batch Poisson arrival, and the packets with Poisson arrival, accumulated in a buffer, are routed by utilizing intervals of the packets with priority. The queueing performance of the proposed model is evaluated by the mean system delay. We also consider the effect of batch size and the ratio of the traffic with batch Poisson arrival and the one with Poisson arrival on the mean system delay. It is found that the proposed queueing model is useful to reduce the mean system delay of the packets with Poisson arrival, while maintaining the means system delay of the packets with batch Poisson arrival.