In this letter, we propose to construct reliable overlay data delivery tree based on group member's packet loss rate while preserving end-to-end delay below predetermined threshold. Through practical simulation, performance is evaluated and compared.

In this paper, we term multimedia streaming application traffic "stream flows" and the other usual application traffic "non-stream flows." Many problems occur when both flows are aggregated on a shared link because the different TCP and UDP behaviors cause negative interactions. One way to solve these problems is to isolate stream and non-stream flows to different classes. However, it is difficult to determine the bandwidth allocation for each class and dynamic bandwidth allocation schemes are hard to implement on large scale networks. We therefore propose a dynamic class assignment method that maintains the QoS and that has a higher scalability than dynamic bandwidth allocation schemes. It is workable on Diffserv AF PHB. The outline is as follows. We classify non-stream flows into four classes and dynamically assign stream flows to the classes, taking the conditions and characteristics of the classes into consideration. On assigning classes to stream flows, we map them to a higher drop precedence than non-stream flows not to degrade the QoS of them, based on the assumption that occasional packets being dropped do not create serious problems for them. In this paper, we first discuss our classification of non-stream flows, and present the characteristics of non-stream flows in each class. We then discuss our drop precedence mapping. After this, we propose an algorithm for our method of dynamic class assignment and provide some simulation results where it could provide constant qualities with stream and non-stream flows, adapting to changing traffic.

A low-power high-frequency sinusoidal quadrature oscillator is presented through a new RC technique using only CMOS current mirrors. The technique is relatively simple based on (1) internal capacitances of CMOS current mirrors and (2) a resistor of a CMOS current mirror for a negative resistance. Neither external capacitances nor inductances are required. As a particular example, a 2.4 GHz-0.4 mW, 0.325-fT, CMOS sinusoidal quadrature oscillator has been demonstrated. The power consumption is very low at approximately 0.4 mW. Total harmonic distortions (THD) are less than 0.3%. The oscillation frequency is current-tunable over a range of 540 MHz or 22%. The amplitude matching and the quadrature phase matching are better than 0.035 dB and 0.15, respectively. A figure of merit called a normalized carrier-to-noise ratio (CNRnorm) is 158.79 dBc/Hz at the 2 MHz offset from 2.46 GHz. Comparisons to other approaches are also presented.

We have investigated the pretilt angle of liquid crystal (LC) molecules induced by photo-alignment films of polyimide (Azo-PI) containing azobenzene in the backbone structure. To generate finite pretilt angles, the Azo-PI film with inclined alignment of the backbone structure was prepared by a double light-exposure method. In this method the corresponding polyamic acid (Azo-PAA) film was first exposed to linearly polarized ultraviolet/visible (UV/VIS) light (LP-light) at normal incidence, and then oblique angle irradiation of unpolarized UV/VIS light (UP-light) was performed in the plane of incidence perpendicular to the polarization direction of the LP-light. Repeated photo-isomerization reactions of azobenzene induce the alignment of the Azo-PAA backbone structure. By thermally imidizing the photo-treated film we obtained a thermally and optically stable Azo-PI film. The orientational distribution of the Azo-PI backbone structure was determined by measuring the polarized infrared absorption spectra as a function of the sample rotation angle and the angle of incidence. The pretilt angle of LC molecules was determined by a crystal rotation method. We found that the average inclination angle of the Azo-PI backbone structure increased with the UP-light exposure. The pretilt angle of LC molecules, measured from the surface plane, also increased with the UP-light exposure. We succeeded in generating a pretilt angle of 3. The relation between the LC pretilt angle and the average inclination angle of the Azo-PI backbone structure is discussed.

This paper presents a new type of optical probe designed to detect magnetic near-fields with high accuracy in the gigahertz range. Its probe head consists of a loop antenna element doubly loaded with LiNbO3 electro-optic crystals. Through an optical technique, it can work as a conventional double-loaded loop probe without metallic cables or an electrical hybrid junction. We examined probe characteristics for magnetic field detection up to 20 GHz. We confirmed that the probe can measure magnetic fields near a microstrip line in the gigahertz range and can suppress influence of electric fields.

In this paper, we consider the problem of multicast routing and wavelength assignment (MC-RWA) in multi-fiber all-optical WDM networks. Two main network design system comprehensively investigated here are mesh and multi-ring designs. Given the multicast traffic demands, we present new ILP formulations to solve the MC-RWA problem with an objective to determine the minimal number of fibers needed to support the multicast requests. Unlike previous studies, our ILP formulations are not only capable of finding the optimal multicast routing and wavelength assignment pattern to the light-trees, but also finding the optimal light-tree structures simultaneously. Since broadcast and unicast communications are special cases of multicast communications, our ILP models are actually the generalized RWA mathematical models of optical WDM networks. In addition to proposing the ILP models, this paper takes two main issues affecting the network capacity requirement into account, that is, the splitting degree level of optical splitters and techniques of wavelength assignment to the light-trees. Three multicast wavelength assignment techniques studied in this paper are Light-Tree (LT), Virtual Light-Tree (VLT) and Partial Virtual Light-Tree (PVLT) techniques. Due to the NP-completeness of the MC-RWA problem, the ILP formulations can reasonably cope with small and moderate networks. To work with large networks, this paper presents alternative MC-RWA ILP-based heuristic algorithms for the PVLT and LT networks and develops lower bound techniques to characterize the performance of our algorithms. Using existing large backbone networks, numerical results are reported to analyze such aspects as multiple fiber systems, the benefits of using optical splitters and wavelength converters, and the capacity difference between the mesh and multi-ring designs. Finally, this paper provides an analysis of the influence of network connectivity on the network implementation under the constraints of mesh and multi-ring design schemes.

In this paper, a new computing paradigm suitable for analog circuit systems is described in comparison to the digital circuit systems. The analog circuit systems have some disadvantages especially in terms of accuracy and stability, but there are some applications that don't require accuracy or stability in circuit component. The new computing concept for such applications, 'inaccurate' information processing, or 'rough' information processing, is proposed and described as well as some examples of such applications.

In this paper, we propose a formal method for detection of three automation surprises in human-machine interaction; a mode confusion, a refusal state, and a blocking state. The mode confusion arises when a machine is in a different mode from that anticipated by the user, and is the most famous automation surprise. The refusal state is a situation that the machine does not respond to a command the user executes. The blocking state is a situation where an internal event occurs, leading to change of an interface the user does not know. In order to detect these phenomena, we propose a composite model in which a machine and a user model evolve concurrently. We show that the detection of these phenomena in human-machine interaction can be reduced to a reachability problem in the composite model.

Circuit techniques to realize stable recall operation and virtually unlimited read/program cycle operations in ferroelectric memory based nonvolatile (NV) SRAM composed of six-transistor and four-ferroelectric capacitor cells have been developed. Unlimited program cycle operation independent of ferroelectric material characteristics is realized by proper control of plate lines. Reliability evaluation results show that the developed memory cell has sufficient operation margin after stresses of temperature, fatigue, DC bias. Application of NV-SRAM to programmable logic devices has been discussed with a prototype of dynamically programmable gate arrays.

Many simulated annealing algorithms use the Cauchy neighbors for fast convergence, and the conventional method uses the product of n one-dimensional Cauchy distributions as an approximation. However, this method slows down the search severely as the dimension gets high because of the dimension-wise neighbor generation. In this paper, we analyze the orthogonal neighbor characteristics of the conventional method and propose a method of generating symmetric neighbors from the n-dimensional Cauchy distribution. The simulation results show that the proposed method is very effective for the search in the simulated annealing and can be applied to many other stochastic optimization algorithms.

This report describes a concrete method for realizing adiabatic charging reversible logic. First, we investigate the stabilization properties of a charge recycle regenerator using a switched capacitor circuit by SPICE simulation and an analytical method. In the N-step case, we proved that a step waveform is spontaneously generated. Next, for combinational logic, we propose an adiabatic charging binary decision diagram logic gate (AC-BDD) that uses this regenerator. The AC-BDD uses pass transistor logic based on a BDD, which is suitable for adiabatic logic. 8-bit AC-BDD multipliers were fabricated, and it is clarified that power consumption is reduced to 15% that of the same-rule-designed CMOS at 1 V and 1 MHz. Finally, we propose clocked energy reversible logic (CERL) that maintains the CMOS architecture for CMOS compatibility. CERL can reduce the clocked energy, which is used for charging the clock load capacitance, to 10% that of CMOS by using a power clock from the charge recycle regenerator.

Some conventional beamformers require the direction of the desired signal. The performance of such beamformers can substantially be degraded even in the presence of small error on the directional information. In this letter, we propose a prefilter-type beamforming scheme robust to directional error by employing a simple compensator. The performance of the proposed scheme is verified by computer simulation.

This letter presents a novel video and audio PTSs self-adaptive interlace strategy in MPEG-2 transport stream. By adaptive regulating the relative position of audio and video access units in bit-stream according to their PTSs, the proposed strategy provides reliable video and audio synchronization.

In this paper, a sub-optimal Rake receiver combined with a Wiener Filter is investigated for use in an indoor environment. Inner-Chip-interference is dominant when the application is indoors, so the inner-chip-interference rejection function becomes critical for the receiver. Pilot symbols in each slot are used for channel estimation and weight calculation of Rake combining through Wiener Filter. Compared to conventional combining which uses maximum ratio combining, Wiener combining using IRC (Interference rejection combining) achieves better ICI (Inner-chip-Interference) rejection. This paper clarified that the sub optimal Rake receiver using Wiener Filter is 4 dB better than the conventional Rake receiver under the indoor application.

In this paper, we propose an optimal bit rate control algorithm which is fully compatible with MPEG-4 or H.263+. The proposed algorithm is designed to identify the optimal quantizer set through Lagrangian optimization when used for optimal bit allocation. To find the optimal quantizer set, we make use of the Viterbi algorithm in order to solve the dependency between quantization parameters of each macroblock due to the unique characteristics of MPEG-4 or H.263+. We set the Lagrangian cost function as a cost function of the Viterbi algorithm. We implement the proposed algorithm in MPEG-4 coders and compare its performance to the VM8 and optimal bit rate control algorithm, using independent quantization parameters in the circumstance of a low bit rate.

An experimental model of a redox microarray, which provides a foundation for constructing future massively parallel molecular computers, is proposed. The operation of a redox microarray is confirmed, using an experimental setup based on an array of microelectrodes with analog integrated circuits.

We will propose a key-agreement-type three-party password-authenticated key exchange protocol. The proposed protocol is quite efficient and, among the same type of protocols, is the first to be formally proven to be secure. A three-party formal model for security proof is proposed based on [25] and [26]. We construct a simulator in this model to show that our proposed protocol is secure under reasonable and well-defined cryptographic primitives.

We propose a multiple-subcarrier (MS) optical communication system using intensity modulation with direct detection (IM/DD) with peak reduction carriers (PRCs) to improve the power efficiency of IM/DD MS systems. The proposed system transmits L subcarriers referred to as PRCs among N subcarriers for the d.c. bias reduction so that the optical power is reduced. Since information bits are mapped onto each subcarrier other than PRCs independently, the information bits of each subcarrier can be detected independently and the error rate of the proposed system is unaffected by PRCs.

An efficient data transmission interface for VLSI systems, Multi-Bit Parallel Code Division Multiple Access (MB/P-CDMA) interface, has been designed with 0.35 µm CMOS technology. The proposed interface achieves 1.12 Gb/s data rate (80 MHz, 8 bit bus) using multi-bit transmission at each clock per transmitter. The proposed CDMA interface ensures higher speed operation than conventional interface even in noisy environments. Each of the transmitters and receivers occupies the die area of 290 360 µm2 and 240 280 µm2, respectively.

This paper presents an asynchronous data transfer scheme using 2-color 2-phase dual-rail encoding based on a differential operation and its circuit realization. The proposed encoding enables seamless asynchronous data transfer without inserting a spacer, because each logic value is represented by two kinds of codewords with dual-rail, called "color" data. Since the difference x-x between components of a codeword (x,x) becomes constant in every valid state, the data-arrival state can be detected by calculating the difference x-x. From the viewpoint of circuit implementation, during the state transition, since the dual-rail x and x are defined so as to transit differentially, the compatibility with a comparator using a differential amplifier becomes high, which results in reduction of the cycle time. It is evaluated using HSPICE simulation with a 0.18 µm CMOS technology that communication speed using the proposed dual-rail encoding becomes 1.4 times faster than that using conventional dual-rail encoding.