Mobile location can be achieved by using the time-of-arrival (TOA) and angle-of-arrival (AOA) measurements. In this Letter, we analyze the location accuracy of an TOA-AOA hybrid algorithm with a single base station in the line-of-sight scenario. The performance of the algorithm is contrasted with the Cramer-Rao lower bound and Federal Communications Commission Emergency 911 requirements.

It is shown that the glass structure change is a simple and widely applicable method to modify refractive index locally in various glass fibers. A small part of a glass fiber is heated immediately to above its melt temperature by arc discharge, and then the molten fiber undergoes rapid cooling, which freezes the change of the glass structure. Therefore the refractive index of the fiber is decreased partially by the glass structure change induced by rapid solidification. The index reduction in a fiber fabricated from multicomponent glasses is estimated to be more than 0.006. To clarify that rapid solidification works for various glasses including silica glasses, long-period gratings are written in a standard telecommunication fiber with various discharge currents and times. The peak loss of more than 25 dB is obtained within only 6 periods. The index change can be adjusted by the discharge conditions. The gratings are not degraded by heating the whole gratings at 700C for 2 hours, and are highly temperature-stable. It is shown that resonance wavelengths can be tuned by controlling the heating temperature and heating time.

This paper first presents an active integrated antenna configuration designed for broadband mobile wireless access systems using the 25-GHz band. This active integrated antenna comprises a microstrip antenna array and RF front-end circuits adopting spatial power combining schemes for reduced power consumption of the power amplifiers. Furthermore, the antenna and RF circuits are integrated into each side of a thick copper backing plate and both are connected through microstrip line /slot transitions. The developed active integrated antenna achieves the output power of 14.6 dBm and a noise figure of less than 5 dB. The wireless system using the developed active integrated antenna achieves a 6-dB improvement in the packet error rate compared to that using a passive antenna with the same array design as the active integrated antenna. Furthermore, we obtained the first license of the active integrated antenna for commercial use in high-speed wireless communication systems in Japan.

The OptIPuter is a radical distributed visualization, teleimmersion, data mining and computing architecture. Observing that the exponential growth rates in bandwidth and storage are now much higher than Moore's Law, this major new project of several universities--currently six in the US and one in Amsterdam--exploits a new world of computing in which the central architectural element is optical networking. This transition is caused by the use of parallelism, as in supercomputing a decade ago. However, this time the parallelism is in multiple wavelengths of light, or lambdas, on single optical fibers, creating a LambdaGrid. Providing applications-centric middleware to control the LambdaGrid on a regional and global scale is a key goal of the OptIPuter and StarLight Optical Switching projects.

In this paper, we consider the problem of estimating the time-varying directions-of-arrival (DOAs) of coherent narrowband cyclostationary signals impinging on a uniform linear array (ULA). By exploiting the cyclostationarity of most communication signals, we investigate a new computationally efficient subspace-based direction estimation method without eigendecomposition and spatial smoothing (SS) processes. The proposed method uses the inherently temporal property of incident signals and a subarray scheme to decorrelate the signal coherency and to suppress the noise and interfering signals, while the null subspace is obtained from the resulting cyclic correlation matrix through a linear operation. Then an on-line implementation of this method is presented for tracking the DOAs of slowly moving coherent signals. The proposed algorithm is computationally simple and has a good tracking performance. The effectiveness of the proposed method is verified through numerical examples.

Speech quality of VoIP (Voice over Internet Protocol) may potentially be degraded by transmission errors such as packet loss and delay that are basically inevitable in best-effort communications. This study newly proposes an error concealment technique for such degradation by taking account of both sender-based and receiver-based techniques. In the proposed technique, sender-based side information, which is required by the receiver-based technique, is transmitted by using steganography, so that its datagram is completely compatible with the conventional format of VoIP. From experimental results of objective evaluation, it is indicated that the proposed technique may potentially be useful for improvement of speech quality, compared with the conventional technique.

This paper proposes a novel extraction method of line parameters for multi-coupled lines on high-speed and high-density PCBs, where it uses TDR measurement in time domain and S-parameter measurement in frequency domain. The accuracy of the proposed method have been verified experimentally by comparing the crosstalk noise in the time domain, where (1) the proposed method extracts RLGC matrices by measuring the test pattern, (2) the crosstalk noise is obtained through SPICE simulation using the extracted RLGC matrices, and (3) the SPICE-simulated crosstalk noise is compared with the measured crosstalk noise. From the crosstalk noise comparison, the proposed method is proven to be very accurate. For N-coupled lines, the proposed method doesn't require expensive 2N-port probe for N-coupled lines but only two-port probe, which provides a simple, accurate, and economic extraction method of line parameters for multi-coupled line on the PCB. In the early stage of PCB design, the proposed method is very useful, because it extracts accurate interconnection parameters of each test board and enables to compensate various side effects due to the variation of PCB fabrication process. Also, the proposed method is necessary to analyze the signal integrity of future high-density and high-speed digital system on PCBs.

We propose an auto-mesh generation algorithm for 3-Dimensional elliptic model on acoustic analysis of the vocal tract. We mesh the vocal tract and compute the vocal tract transfer function (VTTF) using Finite Element Method (FEM). We show there is little difference between the VTTF using our algorithm and that of the manual mesh, especially for vowel /a/. We show that the number of nodes is depended on the shape of the cross section of the vocal tract. Furthermore we compute the VTTF of the vocal tract with variable shape continuously.

Future electric lights will be comprised of white LEDs (Light Emitting Diodes). White LEDs with a high power output are expected to serve in the next generation of lamps. In this paper, an indoor visible data transmission system utilizing white LED lights is proposed. In the proposed system, these devices are used not only for illuminating rooms but also for an optical wireless communication system. This system is suitable for private networks such as consumer communication networks. However, it remains necessary to investigate the properties of white LEDs when they are used as optical transmitters. Based on numerical analyses and computer simulations, it was confirmed that the proposed system could be used for indoor optical transmission.

The design, fabrication, and characterization of monolithic analog phase shifters based on barium-strontium-titanate (BST) coated sapphire substrates with continuously variable 180and 360phase-shift ranges are presented. The phase shifter using a single series resonated termination can provide 180phase shift with the chip area of 4 mm 4 mm. A double series resonated termination in a parallel connection can reach over 370phase shift with better than 6.8 dB-loss at 2.4 GHz. Also, an all-pass network phase shifter composed of only lumped LC elements was described here. This phase shifter demonstrated 160phase shift with an insertion loss of 3.1 dB 1 dB and return loss of better than 10 dB at 2.4 GHz. The total size of the phase shifter is only 2.4 mm 2.6 mm, which is the smallest reported BST phase shifter operating at S-band, to the best of the authors' knowledge.

Implementation issues on generalized multi-protocol label switching (GMPLS) -based photonic switching networks are experimentally analyzed. A resilient control plane architecture using in-fiber and out-of-fiber control channels is proposed to resolve issues of establishing the control plane in out-of-band networks. The resilient control plane is demonstrated in a photonic cross-connect (PXC) -based GMPLS network involving a 1,000 km transmission line. Fast signaling for provisioning and restoration operation is accomplished by implementing in-fiber control channels as primary, and the out-of-fiber control channels effectively operate as secondary and restore messaging of the control information between neighbors. The control channel protection is initiated by the link management protocol (LMP). Using the test bed, optical layer routing operation is investigated to assess the effects on the signal quality of wavelength paths, and transparent routing of the wavelength paths over one-hop and two-hops route is demonstrated within 1 dB difference regarding the Q factor. Stable operation of loss of light (LOL) -triggered restoration is demonstrated by setting the optical level threshold 5 dB higher than the amplified spontaneous emission (ASE) noise level.

This paper proposes a technique for indexing, clustering and retrieving images based on their edge features. In this technique, images are decomposed into several frequency bands using the Haar wavelet transform. From the one-level decomposition sub-bands an edge image is formed. Next, the higher order auto-correlation function is applied on the edge image to extract the edge features. These higher order autocorrelation features are normalized to generate a compact feature vector, which is invariant to shift, image size. We used direction cosine as measure of distance not to be influenced by difference of each image's luminance. Then, these feature vectors are clustered by a self-organizing map (SOM) based on their edge feature similarity. The performed experiments show higher precision and recall of this technique than traditional ways in clustering and retrieving images in a large image database environment.

We report the investigation of major dispersion mechanisms such as self-heating, trapping, current collapse, and floating-body effects present in AlGaN/GaN HFETs. These effects are analyzed using DC/Pulsed IV, load-pull, low-frequency noise systems, and a cryogenic probe station. This study leads to a better understanding of the device physics, which is critical for accurate large-signal modeling and device optimization.

An attenuation measurement system, which employs a traceable inductive voltage divider (IVD) at 1 kHz as a reference standard and dual channel intermediate frequency (IF) substitution method, is developed as an attenuation standard in the frequency range of 5 GHz to 12 GHz. The basic properties of the system are experimentally investigated and the expanded standard uncertainty of the system is estimated to be 0.0018 dB for 20 dB and 0.026 dB for 80 dB attenuation.

The transmission quality in mobile wireless communication systems is affected by not only AWGN but also multi-path fading. Particularly, the Doppler frequency, the delay spread and the Rician factor have a great influence upon the quality over fading channels. This letter proposes the approximate equation for easily calculating the BER in DS-CDMA systems over multi-path fading channels. The validity of the approximate equation is confirmed from the fact that the BER calculated by the equation coincides with that by the computer simulation.

We present a method for recognition of two-hand gestures. Two-hand gestures include fine-grain descriptions of hands under a complicated background, and have complex dynamic behaviors. Hence, assuming that two-hand gestures are an interacting process of two hands whose shapes and motions are described by switching linear dynamics, we propose a coupled switching linear dynamic model to capture interactions between both hands. The parameters of the model are learned via EM algorithm using approximate computations. Recognition is performed by selection of the model with maximum likelihood out of a few learned models during tracking. We confirmed the effectiveness of the proposed model in tracking and recognition of two-hand gestures through some experiments.

We evaluate resolution models for resource allocation in a GMPLS distributed control plane for heterogeneous all-optical networks. In a practical regional-to-backbone network environment, the local resolution model is advantageous in resource utilization, protocol compatibility and scalability. We demonstrate a lookup procedure, which inter-works with OSPF-TE and RSVP-TE protocols and allocates resources in the local resolution model.

In this paper, we propose a blind adaptive channel identification and equalization algorithm with phase offset compensation for single-input multiple-output (SIMO) channel. It is based on the one-step forward multichannel linear prediction error method and can be implemented by an RLS algorithm. Phase offset problem is inherent part of any second-order statistics-based blind identification and equalization. To solve this problem, we use a blind adaptive algorithm called the constant modulus derotator (CMD) algorithm based on constant modulus algorithm (CMA). Moreover, unlike many known subspace (SS) methods or cross relation (CR) methods, our proposed algorithms do not require channel order estimation. Therefore, our algorithms are robust to channel order mismatch.

This paper presents a frequency domain simultaneous equations method capable of automatically recovering noise reduction effect degraded by secondary path changes. The simultaneous equations method has been studied, first in time domain. Accordingly to the study, in the time domain, the simultaneous equations method requires an additional filter and a system identification circuit used for transforming the solution of the simultaneous equations into the coefficients of noise control filter, which increase the processing cost. To reduce the processing cost, this paper studies on the application of a frequency domain processing technique, the cross spectrum method, to the simultaneous equations method. By directly applying the equation defining the cross spectrum method to the solution, the additional filter becomes unnecessary. In addition, the system identification circuit is replaced with the inverse Fourier transform. Thereby, the processing cost drastically decreases. This paper also presents simulation results to confirm that the proposed method can automatically recover the noise reduction effect degraded by a path change and provides much higher convergence speed than that of the filtered-x NLMS algorithm with the perfectly modeled secondary path filter.

An IP (Internet Protocol) over WDM network is expected to be an infrastructure for the next-generation Internet by directly carrying IP packets on the WDM-based network. Among several architectures for IP over WDM networks, one promising way is to overlay a logical topology consisting of lightpaths over the physical WDM network so that IP packets are carried on the lightpaths. The conventional methods for designing the logical topology have been focusing on maximizing throughput of the traffic. However, when the WDM network is applied to IP, the end-to-end path provided by the logical topology of the WDM network is not suitable to IP since IP has its own metrics for route selection. In this paper, we propose a new heuristic algorithm to design a logical topology by considering the delay between nodes as an objective metric. This algorithm uses a non-bifurcated flow deviation to obtain a set of routes that IP packets are expected to traverse. Our proposal is then compared with conventional methods in terms of the average packet delays and throughput. It is shown that our method becomes effective when the number of wavelengths is a limited resource.