In this paper, genetic algorithms is employed to determine the shape of a conducting cylinder buried in a half-space. Assume that a conducting cylinder of unknown shape is buried in one half-space and scatters the field incident from another half-space where the scattered filed is measured. Based on the boundary condition and the measured scattered field, a set of nonlinear integral equations is derived and the imaging problem is reformulated into an optimization problem. The genetic algorithm is then employed to find out the nearly global extreme solution of the object function such that the shape of the conducting scatterer can be suitably reconstructed. In our study, even when the initial guess is far away from the exact one, the genetic algorithm can avoid the local extremes and converge to a reasonably good solution. In such cases, the gradient-based methods often get stuck in local extremes. Numerical results are presented and good reconstruction is obtained both with and without the additive Gaussian noise.

Layered multicast approach enables IP multicast to adapt to heterogeneous networks. In layered multicast, each layer of a session is sent to separate multicast groups. These layers will be transmitted on the same route, or on different routes. However, traditional congestion control schemes of layered multicast do not consider the case when layers of a session are transmitted on different routes. In this paper, at first we show that in sparse-mode routing protocols like PIM-SM and CBT, layers of a session can be mapped to different Rendezvous Points or cores due to the bootstrap mechanism. It means that layers of a session can be transmitted on different routes. We then show that traditional congestion control schemes of layered multicast do not work properly in sparse-mode routing regions. At last we introduce Rendezvous Point based Layered Multicast (RPLM), a novel congestion control scheme suitable for sparse-mode routing regions, and show that RPLM works efficiently in regions using sparse mode routing protocols. RPLM uses per-RP packet loss rate instead of the overall one to detect congestion on each route, and can react to congestion quickly by dropping the highest layer on the congested route. In addition, RPLM simultaneously drops all the layers those are useless in quality's improvement to prevent bandwidth waste.

Support vector machines (SVMs), newly introduced in the 1990s, are promising approach to pattern recognition. They are able to handle linearly nonseparable problems without difficulty, by combining the maximal margin strategy with the kernel method. This paper addresses a novel SVM-based classification scheme of land cover from polarimetric synthetic aperture radar (SAR) data. Polarimetric observations can reveal existing different scattering mechanisms. As the input into SVMs, the polarimetric feature vectors, composed of intensity of each channel, sometimes complex correlation coefficients and textural information, are prepared. Classification experiments with real polarimetric SAR images are satisfactory. Some important properties of SVMs, for example the relation between the number of support vectors and classification accuracy, are also investigated.

Transmission and distribution systems are investigated for application in future fiber optic super-broadband and super-multi-channel subscriber loops. Gradual upgrading is considered so that future systems can keep compatibility with existing systems. First, time frame and strategies for subscriber loop upgrade are overviewed and assumptions for evolution of broadband multimedia distribution systems are discussed. It is suggested that upgrading to super-high definition (SHD) quality multimedia is desirable. Next, some examples of extra-auxiliary picture (EAP) formats are discussed to show the possibility of improving upgradability and compatibility by using extra-channels. Then multiplexing and channel selecting systems are investigated for economical realization of super-multi-channel distribution and flexible channel selection, and hybrid multiplexing (HMUX) and a trans-selector (T-SEL) are proposed. Finally, the efficiencies of HMUX and T-SEL are discussed by using numerical examples. Although broadband down streams are mainly considered, other streams such as IP traffics can be accommodated in the distribution systems investigated in this paper.

This paper presents an application-specific, heterogeneous multiprocessor synthesis system, named HeMPS, that combines a form of Evolutionary Computation known as Differential Evolution with a scheduling heuristic to search the design space efficiently. We demonstrate the effectiveness of our technique by comparing it to similar existing systems. The proposed strategy is shown to be faster than recent systems on large problems while providing equivalent or improved final solutions.

We have developed a novel human facial tracking system that operates in real time at a video frame rate without needing any special hardware. The approach is based on the use of Lie algebra, and uses three-dimensional feature points on the targeted human face. It is assumed that the roughly estimated facial model (relative coordinates of the three-dimensional feature points) is known. First, the initial feature positions of the face are determined using a model fitting technique. Then, the tracking is operated by the following sequence: (1) capture the new video frame and render feature points to the image plane; (2) search for new positions of the feature points on the image plane; (3) get the Euclidean matrix from the moving vector and the three-dimensional information for the points; and (4) rotate and translate the feature points by using the Euclidean matrix, and render the new points on the image plane. The key algorithm of this tracker is to estimate the Euclidean matrix by using a least square technique based on Lie algebra. The resulting tracker performed very well on the task of tracking a human face.

Telepresentations will be popular in the future of ubiquitous digital media. To realize a telepresentation easily over the Internet, we design a communication protocol to control a remote material (digital media) used in a telepresentation. We describe our proposed protocol; RMOP (Remote Material Operation Protocol) in this paper. This protocol specifies commands for material operations such as synchronization of slides, drawing, and pointing. Since this protocol just specifies the common formats through IP networks independent of special functions of presentation tools, it can be applied to various presentation tools. To design the protocol, we consider the trade-off between reliability of IP multicast and practical availability in the actual Internet. We adopt the reliable multicast mechanism to improve reliability but not to lose practicality in the protocol. Also, we describe an implementation of our prototype system using RMOP for a telepresentation. Then we show some evaluations such as the protocol overhead and comparisons with the other existing systems. Last, we show a case study of a telepresentation over the Internet using our system.

In this paper, the statistical characteristics of rain attenuation in the equatorial zone are investigated. A more reasonable LMS channel model incorporating weather impairments is proposed and compared to the weather-affected Ka-band land mobile satellite (LMS) channel model suggested by Loo. The proposed LMS model uses Lutz's LMS channel model as its basis. The PDF of the received signal and BER performance derived from Loo's model and the proposed channel model are quantified and compared to verify the effectiveness of the proposed model. Finally, the influence of weather impairments on the BER performance is evaluated under various weather conditions, which clearly shows the superiority of the proposed model.

We describe a simple all-optical wavelength converter based on a Fabry-Perot semiconductor optical amplifier (FPSOA). We measure its static characteristics in detail and successfully demonstrate its dynamic wavelength-conversion operation (both inverted and non-inverted) at 2.5 Gbit/s. This is the first demonstration of FPSOA-based wavelength conversion. Quasi-digital response is also observed. Low input power, ease of fabrication and good compatibility with WDM networks are important advantages of FPSOA.

We suggest the method to recover the 3D shape of an object by using a color image scanner which has three light sources. The photometric stereo is traditional to recover the surface normals of objects using multiple light sources. In this method, it usually assumes distant light sources to make the optical models simple. But the light sources in the image scanner are so close to an object that the illuminant intensity varies with the distance from the light source, therefore these light sources should be modeled as the linear light sources. In this method, by using these models and two step algorithm; the initial estimation by the iterating computation and the optimization by the non-linear least square method, not only the surface normal but also the absolute distance from the light source to the surface can be estimated. By using this method, we can recover the 3D shape more precisely. In the experimental results, the 3D shape of real objects can be recovered and the effectiveness of the proposed method is shown.

Techniques for human-motion recovery are applicable to a variety of areas, such as sports, dancing, virtual reality, and video-game production. The people who work in this area focus their attention on recovering information on the motion of individuals rather than groups of people. It is important to demonstrate the possibility of recovering descriptions of the 3-D motion in team sports, since such information is able to provide us with a variety of information on the relations among players. This paper presents a new experimental result on 3-D motion recovery from a team sport. The result was obtained by a non-rigid shape recovery technique based on images from uncalibrated cameras. The technique was applied to recovering the 3-D motion of the players in a mini-basketball game which was played in a gymnasium. Some attention is focused on the analysis of the players' motion. Satisfactory results were obtained.

In this study, synchronization phenomena in chaotic oscillators coupled by a transmission line are investigated. In particular investigation using real circuits is done for the first time. It is confirmed that the chaotic subsystems synchronize, although signals propagating along the transmission line are affected by the time delay. Further the period-doubling bifurcation with varying the time delay and anti-phase synchronization phenomena are observed in our circuit model. Also the voltage distribution of transmission line is simulated in order to investigate whether the current flowing through the transmission line is constant or not. It is found that the subsystems synchronize although the current through the transmission line keeps on varying.

In this paper, we propose a frequency domain active noise control (ANC) system without a secondary path model. The proposed system is based on the frequency domain simultaneous perturbation (FDSP) method we have proposed. In this system, the coefficients of the adaptive filter are updated only by error signals. The conventional ANC system using the filtered-x algorithm becomes unstable due to the error between the secondary path, from secondary source to error sensor, and its model. In contrast, the proposed ANC system has the advantage not to use the model. In this paper, we show the principle of the proposed ANC system, and examine its efficiency through computer simulations.

This paper aims to provide a robust multiuser detection structure that adaptively tracks signature waveform distortion for CDMA multipath signals. In practical wireless environment, multipath fading leads to signature waveform distortion that severely degrades the performance of the linear multiuser detectors (LMDs) designed by exploiting the original signature waveform. In what follows, an iterative algorithm is proposed to track the signature waveform perturbation. The rationale of adaptive processing is based on the subspace method and the Minimum Variance Distortionless Response (MVDR) beamforming concept. Performance evaluation reveals that the proposed adaptive multiuser detection structure reduces the impact of signature waveform perturbation on the performance of the LMDs to a great extent. Moreover, the proposed iterative algorithm is near-far resistant since both the subspace method and the MVDR beamforming technique are energy independent to the interferers.

This paper elucidates through experiments the improvement in the achievable bit error rate (BER) performance when space time transmit diversity (STTD) is applied to the wideband direct sequence code division multiple access (W-CDMA) forward link. First, laboratory experimental results clarify that the received path timing difference of transmitted signals from two antennas, due to the propagation delay, should be within a chip duration of approximately 1/4 and 1/2 with and without fast transmit power control (TPC), respectively, in order to achieve a prominent transmit diversity effect. We show that the required average received signal energy per bit-to-background noise spectrum density (Eb/N0) at the average BER of 10-3 using STTD is decreased by approximately 4.2 (1.7) dB compared to the case of single-antenna transmission at the maximum Doppler frequency, fD, of 5 Hz without (with) antenna diversity reception at a mobile station (MS) due to the increasing randomization effect of burst error. Furthermore, we elucidate that although the gain of STTD in field experiments is decreased compared to that in laboratory experiments, since the degradation in path search accuracy is greater due to the frequently changing delay time of each path in a real multipath-fading channel, the required average received signal energy per bit-to-interference plus background noise power spectrum density ratio (Eb/I0) at the average BER of 10-3 with STTD is decreased by approximately 1.3 to 1.5 (0.7 to 1.0) dB without (with) antenna diversity reception when fast TPC is not applied in the forward link. This indicates that STTD is effective for a channel without TPC such as a common control channel in a real multipath-fading channel.

This paper investigates the optimum transmit-antenna-weight generation method for adaptive antenna array transmit diversity (AAA-TD) in the W-CDMA forward link: AAA-TD with beam and null steering (BNST), AAA-TD with beam steering (BST), or switched beam transmit diversity with fixed weights (SBTD-FW). The achievable BER performance after carrier frequency calibration in the transmit beam pattern is compared among the three methods assuming a different carrier frequency in a 2-GHz band with the carrier separation of 184.5 MHz based on computer simulations. The simulation results show that the achievable BER performance in the forward link using AAA-TD with BNST is almost identical to that using AAA-TD with BST when there are many more interfering users than there are array antennas, except for the special case when a small number of higher rate users exists in the reverse link. This is because by performing carrier frequency calibration, the directions of the beam nulls are shifted from the real directions of arrival (DOAs) of the interfering users. However, we also show that the required transmit Eb/N0 at the average BER of 10-3 using AAA-TD with BST is decreased by approximately 1.0 to 1.2 dB compared to that using SBTD-FW with 12 beams.

We analyzed the performance of adaptive array antennas with a RAKE receiver by employing a common correlation matrix of the sample matrix inversion (CCM-SMI) algorithm in a multipath Rayleigh fading environment for W-CDMA reverse link. A common correlation matrix is usually used to provide adaptive weights for multiple users and multiple delay paths and can be used in packet communications transmitted using frame units. The proposed CCM-SMI algorithm had a better BER and SINR for lower computational complexity compared with the conventional SMI algorithm, even when using a RAKE receiver in multipath Rayleigh fading environment.

In this paper, we describe a frame synchronization method for bi-orthogonal modulation systems. In bi-orthogonal modulation systems, several bi-orthogonal sequences are used for data transmission. Frame synchronization in bi-orthogonal modulation systems is difficult because transmitted sequences can change every frame. In the proposed method, each bi-orthogonal sequence consists of two different inner sequences. Each bi-orthogonal sequence has the same arrangement of two different inner sequences. A receiver can track the frame timing by observing the arrangement of inner sequences. In this paper, we analyze the bit error rate performance that takes into account the tracking performance of a system we developed based on our method. The spectral efficiency of the proposed system in code division multiple access (CDMA) systems is also investigated. As a result, we found that the proposed system is effective in synchronous CDMA systems.

PSK coherent demodulation has difficulty in achieving high speed carrier extraction and symbol synchronization when implementing to slow FH-SS radio system. On the other hand, implementation to FPGA has the requirement of a small gate size to design because of FPGA cost issue. We developed a QPSK coherent demodulation digital modem for FH-SS radio systems using FPGA by solving problems. The designed modem performs symbol synchronization with no carrier extractions, under the limitation of the small gate size requirement. The modem employs shift arithmetic operation and a comb digital BPF to achieve very good synchronization lock-up performance with small gate size. In this paper, the symbol synchronization and the carrier tracking scheme are mainly discussed. Analysis of its performance and stability are also explained. The achievement of its very good performance is presented by experimental measurement.

Power-line communication (PLC) systems have been assumed as the systems of low speed and low reliability. The low qualities of the systems, however, are not inherent of PLC but the result of inadequate design strategy of the systems. The systems with proper considerations of the characteristics of power-line as a communication medium achieve reliable high-speed data transmission in power-lines. In fact, the activities on the standardization of high-speed PLC systems have recently started in many countries, and variety of high-speed PLC systems are being to be purchased off-the-shelf. Following this trend of PLC, this manuscript first describes the features of power-line for communications and then explains technical issues on the design of PLC systems of the next generations as the infrastructure of information-communication technology age.