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.
Shouli YAN Edgar SANCHEZ-SINENCIO
Low voltage (LV) analog circuit design techniques are addressed in this tutorial. In particular, (i) technology considerations; (ii) transistor model capable to provide performance and power tradeoffs; (iii) low voltage implementation techniques capable to reduce the power supply requirements, such as bulk-driven, floating-gate, and self-cascode MOSFETs; (iv) basic LV building blocks; (v) multi-stage frequency compensation topologies; and (vi) fully-differential and fully-balanced systems.
Building robots is generally considered difficult, because the designer not only has to predict the interactions between the robot and the environment, but also has to deal with the consequent problems. In recent years, evolutionary algorithms have been proposed to synthesize robot controllers. However, admittedly, it is not satisfactory enough just to evolve the control system, because the performance of the control system depends on other hardware parameters -- the robot body plan -- which might include body size, wheel radius, motor time constant, etc. Therefore, the robot body plan itself should, ideally, also adapt to the task that the evolved robot is expected to accomplish. In this paper, a hybrid GP/GA framework is presented to evolve complete robot systems, including controllers and bodies, to achieve fitness-specified tasks. In order to assess the performance of the developed system, we use it with a fixed robot body plan to evolve controllers for a variety of tasks at first, then to evolve complete robot systems. Experimental results show the promise of our system.
In this paper, we provide a bound of the continuous ARE solution in terms of a matrix associated with Lyapunov solutions. Based on the new matrix-type bound, we also consider various scalar bounds and compare them with existing bounds. The major advantage of our results over existing results is that the new bounds can be always obtained if the stabilizing solution exists, whereas all existing bounds might not be computed because they require other conditions additional to the existence condition.
Moonjae JEONG Satoshi TANAKA Shigetaka TAKAGI Nobuo FUJII Hiroshi KAWAMOTO
This paper presents a 7th-order channel-select filter for a spread-spectrum wireless receiver operating with a minimum power supply of 2.5 V. The channel-select filter implements a sharp transition from 2 MHz to 4 MHz and a stopband attenuation of 50 dB. The 7th-order filter is realized by a cascade of a passive RC integrator, a 3rd-order leapfrog filter, an operational amplifier based differentiator, a 2nd-order notch filter, and a 1st-order allpass filter. It is designed in a 0.35 µm single-poly BiCMOS process. Simulation results show feasibility of the proposed filter.
Mitsuaki KAKEMIZU Kazunori MURATA Masaaki WAKAMOTO
An increase in high quality of service (QoS) applications such as video conferencing and distribution, and the evolution of the Internet have popularized ATM-LAN use based on the private network node interface (PNNI). Also in public networks, which serve as backbone networks for LANs, ATM technology is being introduced for high-speed and broadband communication. These situations lead to a great demand for economically and seamlessly interconnecting remote ATM-LANs via ATM public networks, which are based on broadband ISDN user part (BISUP). This paper discusses a method of peer group configuration method for such internetworking architecture that can avoid an overload of the PNNI routing processing in each peer group. The paper also proposes a method for seamless interconnection of remote ATM-LANs. In this method, complete PNNI signaling and routing is executed between a local switch (LS) in a public network and each ATM-LAN. It also can reduce the PNNI routing processing load on each public network by emulating PNNI routing and signaling between LSs.
Visualization of 3-D ultrasound images is a challenging task due to the noisy and fuzzy nature of ultrasound imaging. This paper presents an efficient volume rendering technique for 3-D ultrasound image. A preprocessing technique of 2-D truncated-median filtering is proposed to reduce speckle noise of the ultrasound image. This paper also introduces an adaptive boundary detection method to reduce the computation time for volume rendering of ultrasound image. The proposed technique is compared to the conventional volume rendering methods with respect to the computation time and the subjective image quality. According to the comparison study, the proposed volume rendering method shows good performance for visualization of 3-D ultrasound image.
This paper analyzes the effective radiation efficiency of a ground-penetrating radar (GPR) consisting of two resistor-loaded bow-tie antennas covered with a ferrite-coated conducting cavity by using finite-difference time-domain (FDTD) method. The GPR is located above a lossless or lossy ground surface. The relation between the radiation powers into the ground and air, dissipated powers at the loaded resistors and ferrite absorber, and the reflected power due to impedance mismatching, is clarified numerically.
Tsunehiro YOSHINAGA Jianliang XU Katsushi INOUE
This paper investigates some fundamental properties of 2-way alternating multi-counter automata (2amca's) with only existential (universal) states which have sublinear space and 1 inkdot. It is shown that for any function s(n) log n such that log s(n)=o(log n), s(n) space-bounded 1-inkdot 2amca's with only existential states are incomparable with the ones with only universal states, and the ones with only existential (universal) states are not closed under complementation.
Akira ARUTAKI Hiroshi IKEDA Masahiko HONDA Kazuhiko ISOYAMA Tatsuhiko AMAGAI Kenji YAMADA Tetsurou NISHIDA
The rapid growth of the Internet impacts ATM networks to be furnished IP handling capability. This paper discusses networking issues for IP and ATM integration. First, it considers function allocation at the boundary of an ATM backbone network and the Internet. As the result, the paper explains the necessity of built-in IP handling capability into an ATM switching system, and summarizes functional requirements for the system architecture. According to the discussion above, the authors propose the system architecture of the IP/ATM integration in the ATM switching system. The implementation of the proposed architecture is evaluated, and the wire-speed IP handling capability in the ATM switch is confirmed.
Kai YANG Hiroyuki KUDO Tsuneo SAITO
We introduce a new wavelet image coding framework using context-based zerotree quantization, where an unique and efficient method for optimization of zerotree quantization is proposed. Because of the localization properties of wavelets, when a wavelet coefficient is to be quantized, the best quantizer is expected to be designed to match the statistics of the wavelet coefficients in its neighborhood, that is, the quantizer should be adaptive both in space and frequency domain. Previous image coders tended to design quantizers in a band or a class level, which limited their performances as it is difficult for the localization properties of wavelets to be exploited. Contrasting with previous coders, we propose to trace the localization properties with the combination of the tree-structured wavelet representations and adaptive models which are spatial-varying according to the local statistics. In the paper, we describe the proposed coding algorithm, where the spatial-varying models are estimated from the quantized causal neighborhoods and the zerotree pruning is based on the Lagrangian cost that can be evaluated from the statistics nearby the tree. In this way, optimization of zerotree quantization is no longer a joint optimization problem as in SFQ. Simulation results demonstrate that the coding performance is competitive, and sometimes is superior to the best results of zerotree-based coding reported in SFQ.
Methods to discover laws are reviewed from among both statistical approach and artificial intelligence approach with more emphasis placed on the latter. Dimensions discussed are variable dependency checking, passive or active data gathering, single or multiple laws discovery, static (equilibrium) or dynamic (transient) behavior, quantitative (numeric) or qualitative or structural law discovery, and use of domain-general knowledge. Some of the representative discovery systems are also briefly discussed in conjunction with the methods used in the above dimensions.
Yuh-Shyan CHEN Tong-Ying JUANG En-Huai TSENG
The arrangement graph An,k is not only a generalization of star graph (n-k=1), but also more flexible. Designing efficient broadcasting algorithm on a regular interconnection network is a fundamental issue for the parallel processing techniques. Two contributions are proposed in this paper. Initially, we elucidate a first result to construct n-k edge-disjoint spanning trees in an An,k. Second, we present efficient (one/all)-to-all broadcasting algorithms by using constructed n-k spanning trees, where height of each spanning tree is 2k-1. The arrangement graph is assumed to use one-port and all-port communication models and packet-switching (or store-and-forward) technique. Using n-k spanning trees allows us to present efficient broadcasting algorithm in the arrangement graphs and outperforms previous results. This is justified by our performance analysis.
Shigetoshi OHSHIMA Katsufumi EHATA Takafumi TOMIYAMA
High-temperature superconducting (HTS) films have low surface resistance in the microwave region. This indicates that HTS passive microwave devices, for example, filters and antennas, are promising for commercial use. For superconducting filters, low insertion loss, sharp skirt property and high attenuation value out of band are important, and for superconducting antennas, electrically small antennas and super-directive high-gain antennas are useful. It is known that the elliptic filter has a sharp skirt property compared with that of a Chebyshev filter. We examined a cross-coupled filter which is one type of elliptic filter. The insertion loss of the filter was approximately 0.3 dB. The skirt property of the four-resonator cross-coupled filter was almost equal to that of an eight-resonator hairpin filter. We also examined a cryocooler cooling system for superconducting antenna and measured the relative gain, directivity and power capability of an HTS antenna. The gain of the HTS patch antenna was approximately 10 dB larger than that of a normal conducting antenna. The large gain of the HTS antenna was caused by the low surface impedance and enhancement effect of the dielectric window of the cooling system.
Eiichiro FUJISAKI Tatsuaki OKAMOTO
This paper presents a simple and generic conversion from a public-key encryption scheme that is indistinguishable against chosen-plaintext attacks into a public-key encryption scheme that is indistinguishable against adaptive chosen-ciphertext attacks in the random oracle model. The scheme obtained by the conversion is as efficient as the original encryption scheme and the security reduction is very tight in the exact security manner.
Nobuyuki YOSHIKAWA Kaoru YONEYAMA
We have developed a parameter optimization tool, Monte Carlo Josephson simulator (MJSIM), for rapid single flux quantum (RSFQ) digital circuits based on a Monte Carlo yield analysis. MJSIM can generate a number of net lists for the JSIM, where all parameter values are varied randomly according to the Gaussian distribution function, and calculate the circuit yields automatically. MJSIM can also produce an improved parameter set using the algorithm of the center-of-gravity method. In this algorithm, an improved parameter vector is derived by calculating the average of parameter vectors inside and outside the operating region. As a case study, we have optimized the circuit parameters of an RS flip-flop, and investigated the validity and efficiency of this optimization method by considering the convergency and initial condition dependence of the final results. We also proposed a method for accelerating the optimization speed by increasing 3σ spreads of the parameter distribution during the optimization.
The applications of reactance-loaded beam tilting dipole antennas have been reported by many researchers. The reactance elements loaded on the applications reported up to date have been used only for the purpose of beam tilting. This paper presents the basic characteristics of the beam tilting dipole antenna element in which one reactance element is used for the impedance matching at the feed point. The radiation pattern is tilted by the properly determined driving point position, and the loading reactance is used to obtain forced resonance without great changes in tilt angle. The numerical results demonstrate that the reactance element should be loaded in the region where the driving point is placed to obtain forced resonance of the antenna with little changes in beam tilt angle. In case the proposed forced resonant beam tilting antenna with 0.8λ length is driven at 0.2λ from the center, the main beam tilt angle of 57.7 degrees, the highest power gain of 8.6 dB, and VSWR=2.2 are obtained.
Mitsushige OKADA Toru KANEKO Kenjiro T. MIURA
A method for locating underground pipes from a pulse radar image is presented. The method employs the Laplacian of Gaussian filter to extract edges and employs the Hough transform to determine the depth of the pipes. A preliminary experiment showed its ability to detect deeply buried pipes with weak signal echoes.
We report on the fabrication and operation of all-NbN single flux quantum (SFQ) circuits with resistively shunted NbN/AlN/NbN tunnel junctions fabricated on silicon substrates. The critical current varied by about 5% in 400 NbN/AlN/NbN junction arrays, where the junction area was 88 µm2. Critical current densities of the NbN/AlN/NbN tunnel junctions showed exponential dependence on the deposition time of the AlN barrier. By using the 12-nm-thick Cu film as shunted resistors, non-hysteretic current-voltage characteristics were achieved. From dc-SQUID measurements, the sheet inductance of our NbN stripline was estimated to be around 1.2 pH at 4.2 K. We designed and fabricated circuits consisting of dc/SFQ converters, Josephson transmission lines, and T flip-flop-based SFQ/dc converters. The circuits demonstrated correct operation with a bias margin of more than 15% at 4.2 K.
Keiji YOSHIDA Haruyuki TAKEYOSHI Hiroshi MORITA
An analytical solution of the London equation for the weakly coupled grain model of high Tc superconducting thin films has been obtained in the case of finite thickness by taking full account of anisotropic conductivities. Using the solution, we provide general expressions for the transmission-line parameters of high Tc superconducting transmission lines. Dependences of the inductance and resistance on the grain size, coupling strength and film thickness have been numerically evaluated and discussed.