This paper proposes an extended variant of the method by Brickel et al. for multiple scalar multiplication over an elliptic curve. In smartcard environments, the proposed method is superior to conventional methods. In particular, when the typical number of bases t=2, the proposed method is four times faster than the simultaneous multiple exponentiation method, a well known fast method for multiple scalar multiplication. Furthermore, the proposed method can change the amount of time and memory to fit various platform environment (e.g., personal computers as rich ones or mobile devices such as smartcards as poor ones) by adjusting the division bit width (division unit).

This paper proposes a method of supporting behavioral decision-making with a rule-based system to be used for the design stage of service specifications or service scenarios based on a state transition model. We consider telecommunication services as service scenarios of state transitions. A state transition can be described as a transition rule that is represented as the notation of an IF-THEN rule : "if < condition > then < action >. " Thus, behaviors or service scenarios are assumed to be treated as a set of IF-THEN rules in this paper. In general, an "if < condition > then < action >" rule is called a production rule, and production rules are often used to represent knowledge in expert systems. Thus, rules treated in this paper are a kind of production rule. It is still difficult to decide if behaviors are concurrent, cooperative, or exclusive as a whole system when many service scenarios are combined, even if each rule is clearly described and easy to understand. When several service scenarios are combined, it is necessary for the sub-elements of each state transition to cooperate. The method proposed in this paper consists of the following techniques: (1) decompositions of a state transition to sub-elements, (2) rule descriptions for the decomposed sub-elements and the application of rules, (3) use of conflict and cooperation strategies, and (4) support for behavioral decision-making by showing recommendations for cooperative, exclusive, or concurrent behavior. We provide examples of telecommunication services to show the effectiveness of the proposed method in an easy-to-understand manner. We also show cooperative resolution in the interactions among several services.

This paper proposes two novel Multi-bit Delta-Sigma Modulator (Δ Σ M) architectures based on a Dual-Quantization architecture. By using multi-bit quantization with single-bit feedback, Both eliminate the need for a multi-bit digital-to-analog converter (DAC) in the feedback loop. The first is a Digital quantization-Error Canceling Multi-bit (DECM)-Δ Σ M architecture that is able to achieve high resolution at a low oversampling ratio (OSR) because, by adjusting the coefficients of both analog and digital circuits, it is able to cancel completely the quantization error injected into the single-bit quantizer. Simulation results show that a signal-to-quantization-noise ratio of 90 dB is obtained with 3rd order 5-bit quantization DECM-Δ Σ M at an OSR of 32. The second architecture, an analog-to-digital mixed (ADM)-Δ Σ M architecture, uses digital integrators in place of the analog integrator circuits used in the Δ Σ M. This architecture reduces both die area and power dissipation. We estimate that a (2+2)-th order ADM-Δ Σ M with two analog-integrators and two digital-integrators will reduce the area of a 4-th order Δ Σ M by 15%.

Loss analysis in bent graded-index optical slab waveguides is given using the modal-matching method. The conformal mapping replaces curved structure by an equivalent straight waveguide with a modified index profile. For this planar waveguide structure, the normal modes are calculated using a multilayer approximation method. The wave incident on the bend is expanded initially into a finite set of normal modes of the equivalent straight structure, and the transverse fields are matched across the junction. The numerical results show the loss formation in the graded-index waveguides and its dependence of the effective index of the corresponding straight waveguide.

It is always difficult to monitor stringent cell loss ratio (CLR), e.g. 10-9, in asynchronous transfer mode (ATM) networks, because its measurement period is too long for real-time measurement. In this paper, we propose new performance monitoring mechanisms for stringent CLR. We consider virtual ATM switches whose resources are much smaller than the real system and thus much higher CLRs will be obtained within a relatively short measurement period. By applying some regression methods in the CLRs obtained from the virtual system, we can estimate the actual CLR of the real system quite accurately and our performance monitoring mechanisms will be operated based on the estimation. Through the numerical examples, our mechanisms are not only more accurate than the traditional methods, but also have shorter measurement periods compared with direct measurement.

It is one of the difficulties in enterprise modeling that we must deal with many fragmented pieces of knowledge provided by various domain-experts, which are usually based on mutually different viewpoints of them. This paper presents a formal approach to integrate those pieces into enterprise-wide model units using Rough Set Theory (RST). We focus on business processes in order to recognize and identify the constituents or units of enterprise models, which would compose the model expressing the various aspects of the enterprise. We defined five model unit types of "resource," "organization," "task," "function," and "behavior. " The first three types represent the static aspect of the enterprise, whereas the last two types represent the dynamic aspect of it. Those units are initially elicited from each domain-expert as his/her own individual model units, then they are integrated into enterprise-wide units using RST. Our approach is methodology-free, and any methodologies can include it in their early stage to identify what composes the enterprise.

Many new multimedia applications involve multiple dynamically changing participants, have stringent source-to-end delay requirements, and consume large amounts of network resources. A conventional algorithm that allows "two coming paths," where nodes in a multicast tree transmit several identical data flows, is therefore not practical. We have developed an algorithm for delay-constrained dynamic routing. This algorithm uses a QoS label to prevent the occurrence of "two coming paths," and can construct an efficient multicast tree for any traffic volume. The proposed algorithm was superior to conventional routing algorithms in terms of cost when nodes were added to or removed from the multicast group during a steady-state simulation.

We examined the creep properties and hazard rates of plastic split alignment sleeves to ensure the long-term reliablity of optical fiber connections. It required a gauge retention force Fr of more than 200 gf to suppress the fluctuation in the insertion loss of a plastic sleeve. From the fluctuation data, we estimated the time-to-failure tf at which the Fr value became 200 gf. We estimated the acceleration parameters, median lifetimes ξ, and hazard rates λ by using the tf values based on the Weibull statistics. The ξ values decreased rapidly with increasing temperature and relative humidity. Small λ values of < 0.01 FITs and of 1 FITs were expected for 20 years in a normal atmosphere (25C/50%RH) and in a more severe case of 25C/90%RH or 45C/50%RH.

New good convolutional codes with optimal free distance are tabulated for the number of memories M 22 and rate R=1/2, which were selected based on the criterion of minimizing the decoding error rate and bit error rate. Furthermore, for R=1/3, 1/4 and M 13, we give the new good codes and make clear the existance of the codes with minimum free distance which achieve to Heller's upper bound for M 16.

A new approach for bandwidth allocation of heterogeneous regulated traffics is proposed for cases of lossless multiplexing and statistical multiplexing under the constraint of maximum delay. Minimum bandwidth required for lossless multiplexing can be expressed as 1-dimensional unconstrained-optimization problem. The corresponding optimality condition gives an optimal bandwidth and buffer requirements. This optimality condition is extended to the case of statistical multiplexing. In case of statistical multiplexing with independent, periodic on-off fluid sources, two random variables representing stochastic worst cases for the amount of traffics generated in an arbitrary time interval are introduced and these are combined optimally. This combined model guarantees the worst case bound for the regulated traffics. Using the proposed approach, bandwidth and buffer requirements of each virtual circuit are obtained simultaneously. As these values are sensitive to multiplexing environments, an effective bandwidth considering trade-off between bandwidth and buffer requirements is introduced. The proposed effective bandwidth can be matched directly with the boundary of the acceptance region, which is less sensitive to mutiplexing environments.

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 method for implementing a metric computation accelerator for fractal image compression using reconfigurable hardware. The most time-consuming part in the encoding of this compression is computation of metrics among image blocks. In our method, each processing element (PE) configured for an image block accelerates these computations by pipeline processing. Furthermore, by configuring the PE for a specific image block, we can reduce the number of adders, which are the main computing elements, by a half even in the worst case.

This paper investigates a hierarchical property based on the number of inkdots in the accepting powers of sublogarithmic space-bounded multi-inkdot two-way alternating Turing machines with only universal states. For each k1 and any function L(n), let strong-2UTMk(L(n)) (weak-2UTMk(L(n))) be the class of sets accepted by strongly (weakly) L(n) space-bounded k-inkdot two-way alternating Turing machines with only universal states. We show that for each k1, strong-2UTMk+1(log log n) - weak-2UTMk(o(log n)) Ø.

In this paper, we propose a realtime concatenation technique between basic skeletal motions obtained by the motion capture technique and etc. to generate a lifelike behavior for a humanoid character (avatar). We execute several experiments to show the advantage and the property of our technique and also report the results. Finally, we describe our applied system called WonderSpace which leads participants to the exciting and attractive virtual worlds with humanoid characters in cyberspace. Our concatenation technique has the following features: (1) based on a blending method between a preceding motion and a succeeding motion by a transition function, (2) realizing "smooth transition," "monotone transition," and "equivalent transition" by the transition function called paste function, (3) generating a connecting interval by making the backward and forward predictions for the preceding and succeeding motions, (4) executing the prediction under the hypothesis of "the smooth stopping state" or "the state of connecting motion", (5) controlling the prediction intervals by the parameter indicating the importance of the motion, and (6) realizing realtime calculation.

A fast method for computing a multiple mP for a point P on elliptic curves is proposed. This new method is based on optimal addition sequences and the Frobenius map. The new method can be effectively applied to elliptic curves E(Fqn), where q is a prime power of medium size (e.g., q 128). When we compute mP over curves E(Fqn) with qn of nearly 160-bits and 11 q 128, the new method requires less elliptic curve additions than previously proposed methods. In this case, the average number of elliptic curve additions ranges from 40 to 50.

This paper, for the first time, presents a provably secure signature scheme with message recovery based on the elliptic-curve discrete logarithm. The proposed scheme is proven to be secure in the strongest sense (i.e., existentially unforgeable against adaptively chosen message attacks) in the random oracle model under the discrete logarithm assumption. We give a concrete analysis of the security reduction. When practical hash functions are used in place of truly random functions, the proposed scheme is almost as efficient as the elliptic-curve version of the Schnorr signature scheme and existing schemes with message recovery such as the elliptic-curve version of the Nyberg-Rueppel and Miyaji schemes.

We study the performance of oblivious routing algorithms that follow minimal (shortest) paths, referred to as minimal oblivious routing algorithms in this paper, using competitive analysis on a d-dimensional, N = 2d-node hypercube. We assume that packets are injected into the hypercube arbitrarily and continuously, without any (e.g., probabilistic) assumption on the arrival pattern of the packets. Minimal algorithms reduce the total load in the network in the first place and they preserve locality. First we show that the well known deterministic oblivious routing algorithm, namely, the greedy routing algorithm, has competitive ratio Ω(N1/2). Then we show a problem lower bound of Ω(Nlog 2 (5/4)/log5 N). We also give a natural randomized minimal oblivious routing algorithm whose competitive ratio is close to the problem lower bound we provide.

Information geometry is applied to the manifold of neural networks called multilayer perceptrons. It is important to study a total family of networks as a geometrical manifold, because learning is represented by a trajectory in such a space. The manifold of perceptrons has a rich differential-geometrical structure represented by a Riemannian metric and singularities. An efficient learning method is proposed by using it. The parameter space of perceptrons includes a lot of algebraic singularities, which affect trajectories of learning. Such singularities are studied by using simple models. This poses an interesting problem of statistical inference and learning in hierarchical models including singularities.

In this paper, we propose a new kind of precoding method, modulated coded vector-TH precoding, to mitigate the channel intersymbol interference. The optimal design of the modulated code in vector TH precoding is presented. The coding gain of modulated coded vector TH precoding over conventional scalar TH precoding scheme is investigated in theory. Some simulation results are reported, which show that the proposed modulated coded vector TH scheme can provide a considerable coding gain compared with the conventional precoding techniques.

Phase locked loops (PLL's) are well known as a threshold extension demodulator for analogue FM signals. This capability may lead to the low bit error rate demodulation for digital FM signals. A PLL has also its native frequency tracking ability and is suited to the demodulation of the signals having large Doppler shifts, for example signals from Low Earth Orbit (LEO) satellites. In this paper, we study the demodulation scheme of Continuous Phase FSK (CPFSK) and Gaussian filtered MSK (GMSK) signals using a Digital Signal Processing type Digital PLL (DSP DPLL). First we propose a DSP DPLL completely equivalent to an Analog PLL (APLL). Next we adopt the sequence estimation scheme to compensate the Inter-Symbol Interference (ISI) associated with the finite loop bandwidth of the DSP DPLL. Through computer simulations it is clarified that the proposed DSP DPLL with sequence estimator can achieve better BER performance compared with the conventional Limiter Discriminator (LD) detection on the AWGN channel. We have also shown that the DSP DPLL with sequence estimator has excellent BER characteristics on Rician fading channels having actual large Doppler shifts.