Within the next few decades, high-end telecommunication systems on the larger nationwide network will require a switching capacity of over 5 Tbps. Advanced optical transmission technologies, such as wavelength division multiplexing (WDM) will support optical-fiber data transmission at such speeds. However, semiconductors may not be capable of high-throughput data switching because of the limitations by power consumption and operating speed, and pin count. Superconducting single flux quantum (SFQ) technology is a promising approach for overcoming these problems. This paper proposed an optical-electrical-SFQ hybrid switching system and a novel switch architecture. This architecture uses time-shifted internal speedup, shuffle and grouping exchange and a Batcher-Banyan switch. Our proposed switch consists of an interface circuit with small buffers, a Batcher sorter, a time-shift-speedup buffer (TSSB), a Banyan switch, and a slowdown buffer. Simulations showed good scalability up to 100 Tbps, which no router could ever offer such features.

The first important step in pre-processing data for 3D virtual colonoscopy requires careful segmentation of a complicated shaped colon. We describe an automatic colon segmentation method with a new patient-friendly bowel preparation scheme. This new bowel preparation makes the segmentation more appropriate for digitally removing undesirable remains in the colon. With the aim of segmenting the colon accurately, we propose two techniques which can solve the partial-volume-effect (PVE) problem on the boundaries between low and high intensity regions. Based on the features of the adverse PVE voxels on the gas and fluid boundary inside the colon, our vertical filter eliminates these PVE voxels. By seriously considering the PVE on the colon boundary, our gradient-magnitude-based region growing algorithm improves the accuracy of the boundary. The result of the automatic colon segmentation method is illustrated with both extracted 2D images from the experimental volumetric abdominal CT datasets and a reconstructed 3D colon model.

This paper surveys the research topics and results on nonlinear theory and its applications which have been achieved in Japan or by Japanese researchers during the last decade. The paticular emphasis is placed on chaos, neural networks, nonlinear circuit analysis, nonlinear system theory, and numerical methods for solving nonlinear systems.

This paper describes an application of a speech translation system to another task/domain in the real-world by using developmental data collected from real-world interactions. The total cost for this task-alteration was calculated to be 9 Person-Month. The newly applied system was also evaluated by using speech data collected from real-world interactions. For real-world speech having a machine-friendly speaking style, the newly applied system could recognize typical sentences with a word accuracy of 90% or better. We also found that, concerning the overall speech translation performance, the system could translate about 80% of the input Japanese speech into acceptable English sentences.

This paper proposes a statistical method to estimate the optimal software release time which minimizes the expected total software cost incurred in both testing and operation phases. It is shown that the underlying cost minimization problem can be reduced to a graphical one. This implies that the software release problem under consideration is essentially equivalent to a time series forecasting for the software fault-occurrence time data. In order to predict the future fault-occurrence time, we apply three extraordinary auto-regressive models by Singpurwalla and Soyer (1985) as the prediction devices as well as the well-known AR and ARIMA models. Numerical examples are devoted to illustrate the predictive performance for the proposed method. We compare it with the classical exponential software reliability growth model based on the non-homogeneous Poisson process, using actual software fault-occurrence time data.

This paper evaluates the security of the block cipher E2 against truncated differential cryptanalysis. We show an algorithm to search for effective truncated differentials. The result of the search confirmed that there exist no truncated differentials that lead to possible attacks for E2 with more than 8 rounds. The best attack breaks an 8-round variant of E2 with either IT-Function (the initial transformation) or FT-Function (the final transformation) using 294 chosen plaintexts. We also found the attack which distinguishes a 7-round variant of E2 with IT- and FT-Functions from a random permutation using 291 chosen plaintexts.

A broadcast distribution system (BDS) is a system for the distribution of digital contents over broadcast channel where the data supplier broadcasts the contents in encrypted form and gives each subscriber a decoder containing a secret decryption key. A traitor is a subscriber who offers the information which allows to decrypt the broadcast. When a pirate decoder is captured, if at least one traitor can be identified from it, a BDS is said to be traitor-tracing. If the data supplier can prevent subscribers from obtaining the contents without recalling their decoders, a BDS is said to be subscriber-excluding. In this paper, we propose an efficient BDS which is both subscriber-excluding and traitor-tracing. We use similar mathematics to a threshold cryptosystem. In the proposed BDS, the maximum number of excluded subscribers reaches the maximum number of traitors in a coalition for which at least one traitor can be identified. We prove that the proposed BDS is secure against ciphertext-only attack if and only if ElGamal cryptosystem is secure against the attack and the discrete logarithm problem is hard. The proposed BDS is the first one which satisfies all the following features: Both subscriber-excluding and traitor-tracing, identifying all the traitors, black box tracing and public key system.

This paper presents an O(n2)-time algorithm for constructing two edge-disjoint paths connecting two given pairs of vertices in a given tournament graph. It improves the time complexity of a previously known O(n4)-time algorithm.

In this paper, we present a new network design problem that is applicable for designing virtual paths (VP's) in an asynchronous transfer mode (ATM) network to efficiently support multicast applications, especially real-time multimedia applications. We first address several alternatives for the solution and compare their properties. Then we focus on a new solution which sets up a semi-permanent VP layout (VPL) and constructs VC trees for different multicast traffic demand patterns based on the constructed VPL. A three-phase heuristic solution is proposed for designing a good virtual-path layout for a given set of multicast traffic demand patterns. By varying the design parameters, we can obtain different VPLs which possess different tradeoffs among some important criteria, namely, the network overhead for a connection setup, routing table resources and control and management cost. Simulations are performed on randomly generated networks to demonstrate the performance and scalability of our solution. To the best of our knowledge, there is no prior known work which takes the multicast connection traffic into account for the VP layout design.

We present a result on the robust stabilization of uncertain nonlinear systems via applying feedback linearization. The allowable size of uncertainty is derived for stability. Based on that, we propose a technique that allows us to handle nonlinear systems which are not input-state linearizable. The usefulness of the technique is illustrated by numerical examples.

The power coupling coefficients between cores of waveguide systems with random geometrical imperfections along the fiber axis are determined by comparing numerical solutions of the coupled mode equations with numerical solutions of the coupled power equations and the dependence of the power coupling coefficient on the correlation length with respect to the propagation constants of modes is clarified. When the correlation length D is small the power coupling coefficient is proportional to κ 2 D where κ is the mean mode coupling coefficient and is independent of the fluctuation of the propagation constants. For sufficiently large D the power coupling coefficient dc decreases in proportion to D-1 with increasing D and when D , dc 0. Then the dependence of the power coupling coefficient on the mode coupling coefficient and the fluctuation of the propagation constants δ β is expressed as a function of a single variable κ /δ β .

In this paper, the electromagnetic scattering from a cylinder with a computer-generated random rough surface is analyzed by a numerical simulation method. The validity of the proposed numerical method is confirmed by comparing the present numerical results with those calculated by the perturbation method to second order and its Pade approximation. It is shown that the present proposed method can be applied to the case where the surface roughness becomes relatively large.

Semantic ambiguity is a serious problem in information retrieval. Query expansion has been proposed as one method of solving this problem. However, queries tend not to have much information for fitting query vectors to the latent semantics, which are difficult to express in a few query terms given by users. We propose a document vector modification method that modifies document vectors based on the relevance of documents. This method is expected to show better retrieval effectiveness than conventional methods. In this paper, we evaluate our method through retrieval experiments in which the relevance of documents extracted from scientific papers is assessed, and a comparison with tfidf is described.

In this paper we present a case study of a hierarchical statistical analysis. The method which we use here bridges the statistical information between process-level and system-level, and enables us to know the effect of the process variation on the system performance. We use two modeling techniques--intermediate model and response surface model--in order to link the statistical information between adjacent design levels. We show an experiment of the hierarchical statistical analysis applied to a Phase Locked Loop (PLL) circuit, and indicate that the hierarchical statistical analysis is practical with respect to both accuracy and simulation cost. Following three applications are also presented in order to show advantage of this linking method; these are Monte Carlo analysis, worst-case analysis, and sensitive analysis. The results of the Monte Carlo and the worst-case analysis indicate that this method is realistic statistical one. The result of the sensitive analysis enables us to evaluate the effect of process variation at the system level. Also, we can derive constraints on the process variation from a performance requirement.

A minimum classification error formulation based on genetic algorithm is proposed for discriminative training of the bigram language model. Results of Chinese dialect identification were reported which demonstrate performance improvement with use of the genetic algorithm over the generalized probabilistic descent algorithm.

This paper deals with the decentralized supervisory control problems of uncertain discrete event systems which are represented as a set of some possible models. For a given global specification, this paper provides the necessary and sufficient conditions for the existence of local supervisors to achieve the specification under model uncertainty.

This paper describes a new algorithm for configuring the array of adders used to add the partial products in a multiplier circuit. The new algorithm reduces not only the number of half adders in an adder tree, but also the number of operands passed to the block generating the final product in a multiplier. The arrays obtained with this algorithm are smaller than Wallace's ones and have fewer outputs than Dadda's arrays. We show some evaluation figures and preliminary simulation results of 4, 8 and 16-bit tree configurations.

Debye's asymptotic series is frequently used for calculation of cylindrical functions. However, it seems that until now this series has not been used in all-purpose programs for numerical calculation of the cylindrical functions. The authors attempt to develop these all-purpose programs. We present some improvements for the numerical calculation. As the results, Debye's series can be used for the all-purpose programs, and it is found out that the series gives sufficient accuracy if some conditions are satisfied.

This paper discusses a gate resizing method for performance enhancement based on statistical static timing analysis. The proposed method focuses on timing uncertainties caused by local random fluctuation. Our method aims to remove both over-design and under-design of a circuit, and realize high-performance and high-reliability LSI design. The effectiveness of our method is examined by 6 benchmark circuits. We verify that our method can reduce the delay time further from the circuits optimized for minimizing the delay without the consideration of delay fluctuation.

The delta-sigma modulator (DSM) is an excellent choice for high-resolution analog-to-digital converters. Recently, a band-pass DSM has been a desirable choice for direct conversion of an IF signal into a digital bit stream. This paper proposes a quadrature band-pass DSM for digitizing a narrow-band IF signal. This modulator can achieve a lower total order, higher signal-to-noise ratio (SNR), and higher bandwidth when compared with conventional band-pass modulators. An experimental prototype employing the quadrature topology has been integrated in 0.6 µm, double-poly, double-metal CMOS technology with capacitors synthesized from a stacked poly structure. This system clocked at 13 MHz and digitized a 200 kHz bandwidth signal centered at 4.875 MHz with 100 dB of dynamic range. Power consumption is 190 mW at 5 V.