This paper proposes an enhanced method for multiple description coding (MDC) using whitening transform. The MDC using correlating transform is an error resilient coding technique that explicitly adds correlation between two descriptions to enable the estimation of one set from the other when one set is dropped in channel. This paper proposes a method to overcome practical problems that decoder must know statistics of original image in the conventional correlating transform method. The MDC using whitening transform does not need additional statistical information to reconstruct a image because the coefficients whitening transformed have uni-variance statistics. Our experimental results show that the proposed method achieves a good trade-off between the coding efficiency and the reconstruction quality. We obtain that PSNR of image reconstructed from two descriptions is about 0.93 dB higher at the 1.0BPP and PSNR from only one description is about 1.88 dB higher than conventional method at the same rate of 'Lena' image.

In content distribution networks (CDNs), the content routing which directs user requests to an adequate server from the viewpoint of improvement of latency for obtaining contents is one of the most important technical issues. Several information, e.g. server load or network delay, can be used for content routing. Network support, e.g. active network, enables a router to select an adequate server by using these information. In the paper, we investigate a server selection policy of a network support approach from the viewpoint of which information to be used for effective server selection. We propose a server selection policy using RTT information measured at a router. Simulation results show that our proposed server selection policy in content routing selects a good server under both conditions where server latency and network delay is a dominant element of user response time. Furthermore, we also investigate about location of routers with network support bringing good performance for our proposed scheme.

This paper proposes a new dynamic multicast routing algorithm for layered streams. Since a layered multicast technique accommodates different types of users in the same multicast group, it helps to provide multicast services in a heterogeneous environment. However, this makes it difficult to construct an efficient routing tree when receivers join or leave a multicast session dynamically. In the proposed algorithm, we adopt a pre-determined path approach to handle such dynamic membership of a layered multicast session without the burden of much additional traffic. Simulation results show that the proposed algorithm can minimize the average multicast tree cost, and that it works well on large-scale networks and those with traffic heterogeneity and a small number of routing control messages.

Arc duration of silver contacts was measured with fixed short gap under the condition of different constant gaps and different constant currents, which are close to the minimum arc current of the contact material. The results indicated that the arc occurred even at the current less than the minimum arc current. The arc duration varies in different operations at the same testing condition and it distributes exponentially in the time range up to 100 microseconds. The time constant τ and the extinction rate λ of the distribution were calculated, and related to the arc current. It was assured by silver electrode arc that, even below the so-called minimum arc current, arc ignition may occur but, in this case, the arc duration is momentary, and, as the arc current decreases, the arc extinction rate becomes large.

The interrupting characteristics of low voltage current limiting circuit breakers have directly relationship with the magnitude and distribution of magnetic field produced by contact system and splitter plates. In order to analyze the influence of configuration of contact system on current limiting characteristics, 3D magnetic field of arc chamber (including contact system, arc, splitter plates) is calculated. Furthermore, the electromagnetic repulsion force of movable contact is also calculated. The results can be used to improve configuration of arc quenching chamber. The cooperation between operating mechanism and electromagnetic repulsion force is also analyzed in this paper.

This paper introduces a design for testability (DFT) scheme for delay faults of a controller-data path circuit. The scheme makes use of both scan and non-scan techniques. First, the data path is transformed into a hierarchically two-pattern testable (HTPT) data path based on a non-scan approach. Then an enhanced scan (ES) chain is inserted on the control lines and the status lines. The ES chain is extended via the state register of the controller. If necessary, the data path is further modified. Then a test controller is designed and integrated to the circuit. Our approach is mostly based on path delay fault model. However the multiplexer (MUX) select lines and register load lines are tested as register transfer level (RTL) segments. For a given circuit, the area overhead incurred by our scheme decreases substantially with the increase in bit-width of the data path of the circuit. The proposed scheme supports hierarchical test generation and can achieve fault coverage similar to that of the ES approach.

The energy conservation law and the optical theorem in the grating theory are discussed: the energy conservation law states that the incident energy is equal to the sum of diffracted energies and the optical theorem means that the diffraction takes place at the loss of the specularly reflection amplitude. A mathematical relation between the optical theorem and the energy conservation law is given. Some numerical examples are given for a TM plane wave diffraction by a sinusoidal surface.

Wireless LAN (WLAN) systems transmit and receive via a common frequency band. In this band, signals of other wireless applications operate on a WLAN beamformer as interferences, and so the problem in adaptive antenna is increasing the canceling performance in the presence of moving interference sources. The performance of conventional adaptive beamformer is severely degraded and the robust adaptive beamformer must be equipped with additional sensors to obtain desired performances. Therefore, in order to avoid having to install additional sensors, an efficient algorithm is necessary. In this paper, we introduce a fast adaptive algorithm with variable forgetting factor, which does not require any further additional modifications. Through computer simulations, we can obtain better performances than those of other techniques under a variety of operating conditions.

Counting the number of points of Jacobian varieties of hyperelliptic curves over finite fields is necessary for construction of hyperelliptic curve cryptosystems. Recently Gaudry and Harley proposed a practical scheme for point counting of hyperelliptic curves. Their scheme consists of two parts: firstly to compute the residue modulo a positive integer m of the order of a given Jacobian variety, and then search for the order by a square-root algorithm. In particular, the parallelized Pollard's lambda-method was used as the square-root algorithm, which took 50CPU days to compute an order of 127 bits. This paper shows a new variation of the baby step giant step algorithm to improve the square-root algorithm part in the Gaudry-Harley scheme. With knowledge of the residue modulo m of the characteristic polynomial of the Frobenius endomorphism of a Jacobian variety, the proposed algorithm provides a speed up by a factor m, instead of in square-root algorithms. Moreover, implementation results of the proposed algorithm is presented including a 135-bit prime order computed about 15 hours on Alpha 21264/667 MHz and a 160-bit order.

This letter addresses the issue of RSVP path management in IP micro-mobility networks. We describe efficient RSVP QoS paths with a minimal impact to the existing protocol and underlying routing infrastructure. The goal of this letter is to reduce RSVP path reservation restoration latency and unnecessary control traffic caused by mobility events. We thus propose a RSVP branch-path rerouting scheme at a crossover router (CR) under IP micro-mobility networks. We show that this scheme could give a good tradeoff between the resource reservation cost and the link usage during the lifetime of a RSVP connection.

Optical Burst Switching (OBS) is one of the most important switching technologies in future optical Internet. One of critical design issues in OBS is how to reduce burst dropping resulting from resource contention. Especially when traffic load is high, there should be frequent deflection routing as well as more contentions in an optical burst-switched network. The burst loss performance can be improved by implementing a proper deflection routing scheme. In this paper, we propose a limited deflection routing scheme to prevent injudicious deflection routing. The proposed scheme reduces unnecessary contentions resulting from deflection routing itself, increasing the utilization of network resource such as channels. Simulation tests were performed to evaluate the performance of the proposed scheme.

An optical fiber line testing system is essential for reducing maintenance costs and improving service reliability in optical access networks. NTT has already developed such a system called AURORA (AUtomatic optical fibeR opeRAtions support system). As we already use the 1310 and 1550nm wavelengths for communication, we use the 1650nm wavelength for maintenance testing in accordance with ITU-T recommendation L.41. Recently, a long wavelength band (L-band) that extends to 1625nm has begun to be used for WDM transmission. With a view to monitoring optical fiber cables transmitting L-band communication light, an attractive way of separating the U-band wavelength of the test lights from the L-band wavelength of the communication light is to use a chirped fiber Bragg grating (FBG) filter because of its steep optical spectrum. However, it is difficult to measure fiber characteristics with an optical time-domain reflectometer (OTDR), because multi-reflections appear in the OTDR trace when FBG filters are installed at both ends of an optical fiber line. In this paper, we consider this problem and show that the reflection loss at the port of a test access module (TAM) must be more than 36.6dB. We also describe the system design for an extended optical fiber line testing system using an L/U-band optical coupler, which has two chirped FBGs between two 4-port circulators for L-band WDM transmission. In this system, the reflection loss at a TAM port was 38.1dB, and we confirmed that there was no degradation in the OTDR trace caused by multi-reflections at the optical filters.

A Radio Network (RN, for short) is a distributed system with no central arbiter, consisting of p radio stations each of which is endowed with a radio transceiver. In this work we consider single-hop, single channel RNs, where each station S(i), (1ip), initially stores si items which are tagged with the unique destination they must be routed. Since each item must be transmitted at least once, every routing protocol must take at least n = s1 + s2 + + sp time slots to route each item to its final destination. Similarly, each station S(i), (1ip), must be awake for at least si + di time slots to broadcast si items and to receive di items, where di denotes the number of items destined for S(i). The main contribution of this work is to present a randomized time- and energy-optimal routing protocol on the RN. Let qi, (1ip), be the number of stations that have items destined for S(i), q=q1 +q2 ++ qp, and ri be the number of stations for which S(i) has items. When qi is known to station S(i), our routing protocol runs, with probability exceeding 1 - , (f > 1), in n + O(q + log f) time slots with each station S(i) being awake for at most si + di + O(qi + ri + log f) time slots. Since qidi, risi, and qn always hold, our randomized routing protocol is optimal. We also show that, when the value of di is known to S(i), our routing protocol runs, with probability exceeding 1 - , (f > 1), in O(n + log f) time slots with no station being awake for more than O(si + di + log f) time slots.

The c-Secure CRT code is a collusion-secure fingerprinting code whose code length is reduced by using the Chinese Remainder Theorem. The tracing algorithm for the c-secure CRT code drops its performance of traitor tracing when random errors are added to the codewords. In this paper, we show two approaches to enhance random-error-resilience to the tracing algorithm of the c-secure CRT code. The first approach is introducing thresholds for the distinction of the detected part of the embedded data called detected blocks. We propose a method to derive appropriate values of the thresholds on an assumption that the tracer can estimate the random error rate. This modification extends the capability of traitor tracing to the attacks in which the alteration rate of the detected blocks is not fixed to 0.5. The second approach is extending the scope of the search for the detected blocks. With numerical results by computer simulations, we confirmed an impressive improvement of random-error-resilience of a c-secure CRT code.

This paper describes the realization of a dynamically reconfigurable logic LSI based on a novel parallel computer architecture. The key point of the architecture is its dual-structured cell array which enables dynamic and autonomous reconfiguration of the logic circuits. The LSI was completed by successfully introducing two specific features: fully asynchronous logic circuits and a homogeneous structure, only LUTs are used.

Fingerprinting is one of the digital watermarking techniques, and is becoming more important as a copyright protection technique. Fingerprinting must resist collusion attacks. As a security index, "c-secureness" has been proposed, but it has been known that there is indeed no c-secure code. In this paper, we introduce a new index to measure the resilience of fingerprinting for collusion attacks and obtain some upper bounds and a lower bound on the index.

The generation of high repetition-rate optical pulse train using a passively mode-locked figure-8 fiber ring laser is presented. The laser employs a novel configuration incorporating a superstructure fiber Bragg grating. Pulse train with repetition rates up to 100GHz is possible and transform-limited pulses with pulsewidth below 1ps can be achieved with chirp compensation. The output pulses can further be reduced to 83fs with an external pulse compressor.

It is found that the supercontinuum spectrum is generated from cross-phase modulated soliton pulses which are propagated through a dispersion-flattened/decreasing fiber with low birefringence. The cross-phase modulation is achieved by exciting two orthogonally polarized modes in a birefringent fiber and the effect of input azimuth of linearly polarized pulses is discussed theoretically and numerically.

This paper describes the scalability of a full-mesh wavelength division multiplexing star-structure network based on an arrayed-waveguide grating router (AWG-STAR). The scalability of the network is examined experimentally. A power penalty of 0.1dB is obtained with a 32-node network and an estimated scalability of up to 100 nodes is confirmed.

The one dimensional cutting stock problem (1D-CSP) is one of the representative combinatorial optimization problems, which arises in many industries. As the setup costs of cutting patterns become more dominant in recent cutting industry, we consider a variant of 1D-CSP, in which the total number of applications of cutting patterns is minimized under the constraint that the number of different cutting patterns is specified in advance. We propose a local search algorithm that uses the neighborhood obtained by perturbating one cutting pattern in the current set of patterns, where the perturbations are done by utilizing the dual solution of the auxiliary linear programming problem (LP). In this process, in order to solve a large number of LPs, we start the criss-cross variation of the simplex algorithm from the optimal simplex tableau of the previous solution, instead of starting it from scratch. According to our computational experiment, it is observed that the proposed algorithm obtains a wide variety of good solutions which are comparable to the existing heuristic approaches.