It is well known that KT method proposed by R. Kumaresan and D. W. Tufts is used as a popular parameter estimation method of exponentially damped signal. It is based on linear backward-prediction method and singular value decomposition (SVD). However, it is difficult to estimate parameters correctly by KT method in the case when high noise exists in the signal. In this paper, we propose a parameter (frequency components and damping factors) estimation method to improve the performance of KT method under high noise. In our proposed method, we find the signal zero groups by calculating zeros with different data record lengths according to the combination of forward-prediction and backward-prediction, the mean value of the zeros in the signal zero groups are calculated to estimate the parameters of the signal. The proposed method can estimate parameters correctly and accurately even when high noise exists in the signal. Simulation results are shown to confirm the effectiveness of the proposed method.

IPv6 is designed to solve the exhaustion of the address space, which are one of the biggest problems in the current Internet. The WIDE project has been involved in IPv6 since its early stage, and organized the KAME project in 1998 in order to accelerate its deployment. The KAME project has provided a free, specification-compliant implementation of IPv6 on BSD variants. With its quality and the continuous efforts on it, the implementation has established the position of a reference to IPv6, and has been adopted in BSD variants and in several commercial products. This paper first gives an overview of the IPv6 specifications, including its plug-and-play function, API, DNS, security and transition tools. It then describes the implementation by the KAME project. It is based on the BSD's original network stack, but explores some original enhancements for Neighbor Discovery or IPv6 addressing. Finally, it explains what is missing for the next steps of IPv6, concentrating on plug-and-play and security. The KAME project has joined, and will continue, the standardization and implementation efforts on the new issues.

A scalable MOSFET parasitic model has been studied using 0.13 µm standard CMOS process. The model consisted of a core BSIM3v3 transistor model and parasitic resistor, capacitor, inductor, and diode. All parasitic components' values were automatically calculated by transistor geometrical parameters, only gate length (Lg), gate width (Wg), and gate multiple numbers (Mg), and some fixed process parameters such as sheet resistance of each part of diffusion layer. This model was confirmed for 0.25 µm to 0.5 µm gate length, 10 to 40 gate multiples with 5 µm gate finger width (Wf), 0.8 V to 1.5 V gate-source voltage (|Vgs|) with 0.6 V threshold voltage (|Vth|), and 1.0 V to 2.5 V drain-source voltage (|Vds|) from the viewpoint of small signal. The measured s-parameter and simulated one are in fairly good agreement in 200 MHz to 20 GHz frequencies range. This model is very simple, scalable, and convenient for RF circuit designers without difficult parameter setting.

Many services on the Internet are provided by multiple identical servers in order to improve performance and robustness. The number, the location and the distribution of servers affect the performance and reliability of a service. The server placement is, however, often determined based on the empirical knowledge of the administrators. This paper investigates issues of the server placement in terms of the service performance and the server load. We identify that a server selection mechanism plays an important role in server placement, and thus, evaluate different server selection algorithms. The result shows that it is essential to the robustness of a service to employ a mechanism which distributes service requests to the servers according to the measured response time of each server. As a case study, we evaluate the server selection mechanisms employed by different DNS (Domain Name System) implementations. Then, we show the effects of the different server selection algorithms using root-server measurements taken at different locations around the world.

A number of results on the estimation of direction of arrival have been obtained based on the assumption that the signal sources are point sources. Recently, it has been shown that signal source localization can be accomplished more adequately with distributed source models in some real surroundings. In this paper, we consider modeling of three-dimensional distributed signal sources, in which a source location is represented by the center angles and degrees of dispersion. We address estimation of the elevation and azimuth angles of distributed sources based on the proposed distributed source modeling in the three-dimensional space using two linear arrays. Some examples are included to more explicitly show the estimation procedures under the model: numerical results obtained by a MUSIC-based method with two uniform linear arrays are discussed.

This paper describes truncated and impossible differentials of Feistel block ciphers with round functions of 2-layer SPN (Substitution and Permutation Network) transformation modules such as the 128-bit block cipher Camellia, which was proposed by NTT and Mitsubishi Electric Corporation. Our work improves on the best known truncated and impossible differentials, and has found a nontrivial 9-round truncated differential that may lead to a possible attack against a reduced-round version of Camellia without input/output whitening, FL or FL-1 (Camellia-NFL), in the chosen plain text scenario. Previously, only 6-round differentials were known that may suggest a possible attack of Camellia-NFL reduced to 8-rounds. We also show a nontrivial 7-round impossible differential, whereas only a 5-round impossible differential was previously known. We also consider the truncated differential of a reduced-round version of Camellia (Camellia-DS) whose round functions are composed of D-S (Diffusion and Substitution) transformation modules and without input/output whitening, FL or FL-1 (Camellia-DS-NFL), and show a nontrivial 9-round truncated differential, which may lead to a possible attack in the chosen plain text scenario. This truncated differential is effective for general Feistel structures with round functions composed of S-D (Substitution and Diffusion) or D-S transformation.

This paper presents a fuzzy control-based intelligent medium access controller (FiMAC), which optimizes random access control between heterogeneous traffic aiming at more efficient voice/data integrated services in dynamic reservation TDMA-based broadband radio access networks. In order to achieve the design objective, viz. a differentiated quality-of-service (QoS) guarantee for individual service plus maximal system resource utilization, the FiMAC intelligently and independently controls the random access parameters such as the lengths of random access regions dedicated to respective service traffic and the corresponding permission probabilities, frame-by-frame basis. In addition, we have adopted a mobile-assisted random access mechanism where the voice terminal readjusts a global permission probability from the FiMAC, to handle the 'fair access' issue resulting from distributed queueing problems inherent in the access network. Our extensive simulation results indicate that the FiMAC is well coordinated with a mobile-assisted mechanism such that significant improvements are achieved in terms of voice capacity, delay, and fairness over most of the existing MAC schemes for the integrated services.

A 3D display using super high-density multi-view images should enable reproduction of natural stereoscopic views. In the super multi-view display system, viewpoints are sampled at an interval narrower than the diameter of the pupil of a person's eye. With the parallax produced by a single eye, this system can pull out the accommodation of an eye to an object image. We are now working on a real-time view-interpolation system for the super multi-view 3D display. A multi-view camera using convergence capturing to prevent resolution degradation captures multi-view images of an object. Most of the data processing is used for view interpolation and rectification. View interpolation is done using a high-speed image-processing board with digital-signal-processor (DSP) chips or single instruction stream and multiple data streams (SIMD) parallel processor chips. Adaptive filtering of the epipolar plane images (EPIs) is used for the view-interpolation algorithm. The multi-view images are adaptively interpolated using the most suitable filters for the EPIs. Rectification, a preprocess, converts the multi-view images in convergence capturing into the ones in parallel capturing. The use of rectified multi-view images improves the processing speed by limiting the interpolation processing in EPI.

This paper proposes a flexible tree-based key management framework for a terminal to connect with multiple content distribution systems (called as CDSs in this paper). In an existing tree-based key management scheme, a terminal keeps previously distributed node keys which are used for decrypting contents from a CDS. According to our proposal, the terminal can calculate its node keys of a selected CDS as the need arises, using the "public bulletin board" of the CDS. The public bulletin board is generated by a management center of the individual CDS, depending on a tree structure which it determines in its convenience. After the terminal calculates its node keys, it can get a content of the CDS using the calculated node keys.

The encryption algorithm Camellia is a 128 bit block cipher proposed by NTT and Mitsubishi, Japan. Since the algebraic degree of the outputs after 3 rounds is greater than 128, designers estimate that it is impossible to attack Camellia by higher order differential. In this paper, we show a new higher order differential attack which controls the value of differential using proper fixed value of plaintext. As the result, we found that 6-round F-function can be attacked using 8th order differentials. The attack requires 217 chosen plaintexts and 222 F-function operations. Our computer simulation took about 2 seconds for the attack. If we take 2-R elimination algorithm, 7-round F-function will be attacked using 8th order differentials. This attack requires 219 chosen plaintexts and 264 F-function operations, which is less than exhaustive search for 128 bit key.

This letter derives low-complexity frame and coarse frequency-offset synchronization techniques for orthogonal frequency division multiplexing (OFDM)-based HIPERLAN (HIgh PErformance Radio LAN) system. We first propose a frame detector structure directly based on the correlation method and a reduced complexity structure having the similar performance compared with conventional correlation method. We then propose a coarse frequency-offset synchronization technique and show the performance of the proposed techniques by simulation.

In this paper, a new method is proposed for supervised classification of ground cover types by using polarimetric synthetic aperture radar (SAR) data. The concept of similarity parameter between two scattering matrices is introduced for characterizing target scattering mechanism. Four similarity parameters of each pixel in image are used for classification. They are the similarity parameters between a pixel and a plane, a dihedral, a helix and a wire. The total received power of each pixel is also used since the similarity parameter is independent of the spans of target scattering matrices. The supervised classification is carried out based on the principal component analysis. This analysis is applied to each data set in image in the feature space for getting the corresponding feature transform vector. The inner product of two vectors is used as a distance measure in classification. The classification result of the new scheme is shown and it is compared to the results of principal component analysis with other decomposition coefficients, to demonstrate the effectiveness of the similarity parameters.

In this paper, we consider the similar software cost models with periodic rejuvenation to Garg, Puliafito, Telek and Trivedi (1995) under the cost effectiveness criteria. First, an alternative model as well as the original one are analyzed by Markov regenerative processes. We derive analytically the optimal periodic software rejuvenation policies which maximize the cost-effectiveness in the steady state for two models. Further, we develop statistical non-parametric algorithms to estimate the optimal software rejuvenation policies, provided that the sample data to characterize the system failure times are given. Then, the total time on test (TTT) concept is used. In numerical examples, we compare the periodic software rejuvenation policy with the non-periodic one, and investigate the asymptotic properties of the non-parametric estimators for the optimal software rejuvenation policies through a simulation experiment.

This paper presents circuit models for the description of the frequency-dependent behavior of coils for horizontal deflection in CRTs. This enables CRT circuit designers to use circuit simulation programs to predict the high-frequency behavior of the interaction between the deflection coils and the drive circuit. An overview is given of the major phenomena that occur in CRT deflection coils at various frequencies. Models are presented for the dissipative, the capacitive, and the resonant behavior in successive frequency intervals. With these models, phenomena such as power dissipation and ringing can not only be related to design parameters, but can also be calculated from impedance characteristics which are relatively easy to measure.

The one-sample locally optimum rank detector test statistics for composite signals in multiplicative and signal-dependent noise are obtained. Since the one-sample locally optimum rank detector makes use of the sign statistics of observations as well as the rank statistics, both 'even' and 'odd' score functions have to be considered. Although the one-sample locally optimum rank detector requires two score functions while the two-sample detector requires only one score function, the one-sample detector requires fewer calculations since it has to rank fewer observations.

A virtual city, a virtual reality system to display an urban scene, is one of the most promising tools for ITS applications, including car navigation aids, shopping guides, and city planning, to name a few. This paper overviews our effort to create virtual cities through a sequence of images obtained with vision/range sensors. Our virtual city consists not of only stationary buildings but also of running and parked vehicles, which reflect the current activities in the real city. The first part of this paper describes how to construct still building images from a sequence of images. Here, we focus on methods employing an omni image camera that acquires images containing rays of 360 degrees viewing directions. The second part describes a system to display vehicle movement in the virtual city based on the image sequence given with a monitoring TV camera at an intersection. It also describes a preliminary step toward displaying illegal parked vehicles from information collected by a probe car.

In recent years, perpendicular magnetic recording have progressed rapidly. It will not be long before perpendicular magnetic recording is put into practical use. However there have been few tools contributing to the optimum design of perpendicular magnetic recording media and heads except computer simulations. The authors have introduced a simple method based on the concept of self-consistent magnetization to analytically predict a transition parameter in terms of parameters of recording media and writing heads. Moreover we have discussed the origin of media noise by using a time-domain analysis of readout voltage and Voronoi cell model analysis. In this paper, main parameters to realize high bit density recording over 100 Gbit/inch2 is discussed first through these methods, and then the current status, the future problems and the prospects in perpendicular magnetic recording technology are described.

Since any suggestion to regional services are not described in Kerberos, authentication between regions can be performed via PKINIT (Public Key Cryptography for Initial Authentication) presented by IETF (Internet Engineering Task Force) CAT working group. In this paper, an efficient Kerberos authentication mechanism associated with X.509 and Domain Name system (DNS) is presented by employing the two distinct key management systems - asymmetric and symmetric methods. A new protocol is better than the authentication mechanism proposed by IETF CAT Working group in terms of communication complexity.

ZCZ sets are families of sequences, whose periodic auto/cross-correlation functions have zero correlation zone at the both side of the zero-shift. They can provide approximately synchronized CDMA systems without intra-cell interference for cellular mobile communications. This paper presents ternary ZCZ sets achieving a mathematical bound, and investigates the average interference parameters for the sets in order to evaluate inter-cell interference. It is shown that they can provide AS-CDMA systems with efficiency frequency usage.

We have demonstrated synchronization of chaos in a pair of one-way coupled Colpitts oscillators by both experiment and numerical simulation. We have investigated parameter regions for achieving chaos-synchronization when one of the internal parameters is mismatched between the master and slave oscillators, and clarify the tolerance of parameter regions for synchronization against parameter mismatching.