In this paper, we address the issue of mobile positioning and tracking after measurements have been made on the distances and possibly directions between an MS (mobile station) and its nearby base stations (BS's). The measurements can come from the time of arrival (TOA), the time sum of arrival (TSOA), the time difference of arrival (TDOA), and the angle of arrival (AOA). They are in general corrupted with measurement noise and NLOS (non-line-of-sight) error. The NLOS error is the dominant factor that degrades the accuracy of mobile positioning. Assuming specific statistic models for the NLOS error, however, we propose a scheme that significantly reduces its effect. Regardless of which of the first three measurement types (i.e. TOA, TSOA, or TDOA) is used, the proposed scheme computes the MS location in a mathematically unified way. We also propose a method to identify the TOA measurements that are not or only slightly corrupted with NLOS errors. We call them nearly NLOS-error-free TOA measurements. From the signals associated with TOA measurements, AOA information can be obtained and used to aid the MS positioning. Finally, by combining the proposed MS positioning method with Kalman filtering, we propose a scheme to track the movement of the MS.

A multiple-output function can be represented by a binary decision diagram for characteristic function (BDD_for_CF). This paper presents a method to represent multiple-output incompletely specified functions using BDD_for_CFs. An algorithm to reduce the widths of BDD_for_CFs is presented. This method is useful for decomposition of incompletely specified multiple-output functions. Experimental results for radix converters, adders, a multiplier, and lists of English words show that this method is useful for the synthesis of LUT cascades. An implementation of English words list by LUT cascades and an auxiliary memory is also shown.

In a frequency-selective multiple-input multiple-output (MIMO) channel, the optimum transmission is achieved by beamforming with eigenvectors obtained at each discrete frequency point, i.e., an extension of eigenbeam-space division multiplexing (E-SDM). However, the calculation load of eigenvalue decomposition at the transmitter increases in proportion to the number of frequency points. In addition, frequency-independent eigenvectors increase the delay spread of the effective channel observed at the receiver. In this paper, we propose a pseudo eigenvector scheme for the purpose of mitigating the calculation load and maintaining frequency continuity (or decreasing the delay spread). First, we demonstrate that pseudo eigenvectors reduce the delay spread of the effective channels with low computational complexity. Next, the practical performance of the pseudo E-SDM (PE-SDM) transmission is evaluated. The simulation results show that PE-SDM provides almost the same or better performance compared with E-SDM when the receiver employs a time-windowing-based channel estimation available in the low delay spread cases.

Ziv-Lempel incremental parsing [1] is a fundamental algorithm for lossless data compression. There is a simple enumerative implementation [7] which preserves a duality between the encoder and the decoder. However, due to its compactness, the implementation when combined with a complete integer code, allows only an input sequence with a length consistent with the parsing boundaries. In this letter, we propose a simple additional mechanism for post-processing a binary file of arbitrary length, provided the file punctuation is externally managed.

In this paper, we propose a new scheme to represent three-dimensional (3-D) dynamic scenes using a hierarchical decomposition of depth maps. In the hierarchical decomposition, we split a depth map into four types of images: regular mesh, boundary, feature point and number-of-layer (NOL) images. A regular mesh image is obtained by down-sampling a depth map. A boundary image is generated by gathering pixels of the depth map on the region of edges. For generating feature point images, we select pixels of the depth map on the region of no edges according to their influence on the shape of a 3-D surface, and convert the selected pixels into images. A NOL image includes structural information to manage the other three images. In order to render a frame of 3-D dynamic scenes, we first generate an initial surface utilizing the information of regular mesh, boundary and NOL images. Then, we enhance the initial surface by adding the depth information of feature point images. With the proposed scheme, we can represent consecutive 3-D scenes successfully within the framework of a multi-layer structure. Furthermore, we can compress the data of 3-D dynamic scenes represented by a mesh structure by a 2-D video coder.

This paper presents an active quality of service (QoS) aware service composition protocol for mobile ad hoc networks (MANETs), with the goal of conserving resources subject to QoS requirements. A problem of QoS based service composition in MANETs is transformed into a problem of the service path discovery. We extend Dynamic Source Routing protocol to discover and compose elementary services across the network. Some message processing measures are taken to effectively reduce control overhead. Simulation results demonstrate the effectiveness of the proposed protocol.

It is well known that Pisarenko's frequency estimate for a single real tone can be computed easily using the sample covariance with lags 1 and 2. In this Letter, we propose to use alternative covariance expressions, which are inspired from the modified covariance (MC) frequency estimator, in Pisarenko's algorithm. Computer simulations are included to corroborate the theoretical development of the variant and to demonstrate its superiority over the MC and Pisarenko's methods.

Impulse Radio (IR)-Ultra Wideband (UWB) enables accurate ranging due to very short duration pulses. Therefore, UWB may provide accurate positioning capability. In order to relax the complexity in circuit implementation, UWB system with low resolution analog digital converters (ADCs) has been investigated. In this paper, the accuracy of UWB positioning with comparators is investigated through experiment. The accuracy of positioning with comparators is compared to that with 8 [bit] ADCs, and effectiveness of the system with the comparators is confirmed within the area of 1.81.8 [m].

Existing anomaly intrusion detection that monitors system calls has two problems: vast false positives and lack of risk information on detection. In order to solve the two problems, we propose an intrusion detection method called "Callchains." Callchains reduces the false positives of existing anomaly intrusion detection by restricting monitoring to the activities with process capabilities prescribed by POSIX 1003.1e. Additionally, Callchains provides an administrator information of used POSIX capabilities in sytem call execution as an indicator of risk. This paper shows Callchains' design, its implementation, and experimental results comparing Callchains with existing approaches.

In multiple-input multiple-output (MIMO) wireless relay networks, simultaneously using multiple relay nodes can improve the capacity of source-to-destination communications. Recent information theories have shown that passing the same message across multiple relay nodes can improve the capacity of source-to-destination communications. We have previously proposed three relay schemes that use jointly QR decomposition and the phase control matrix; computer simulations have confirmed the superiority of these schemes over conventional ones such as amplify-and-forward and zero-forcing schemes. In this paper, we analyze the capacity and achievable gains (distributed array gain, intra-node array gain and spatial multiplexing gain) of the previously proposed relay schemes (QR-P-QR, QR-P-ZF, and ZF-P-QR) and thus provide an insight into what contributes to their superiority over conventional schemes. The analyses show that the location of the relay nodes used has a significant impact on capacity. On the basis of this observation, we further propose a method that enables each relay node to individually select its relay scheme according to its channel conditions so as to maximize the capacity. A computer simulation confirms the capacity improvement achieved by the proposed selection method.

IP (Intellectual Property) reuse plays an important role in modern IC design so that IP Protection (IPP) technique is get concerned. In this paper, we introduce a new efficient watermarking system for IPP on post-layout design stage. The signature (which indicates the designer) is encrypted with a secret key by DES (Data Encryption Standard) to produce a bit string, which is then embedded into the layout design as constraints by using a specific incremental router. Once the design is watermarked successfully, the signature can be extracted accurately by the system. The system also has a strong resistance to the attack on watermarking due to the DES functionality. This watermarking technique uniquely identifies the circuit origin, yet is difficult to be detected or fabricated without our tool. We evaluated the watermarking system on IBM-PLACE 2.0 benchmark suites. The results show the system robustness and strength: the system success probability achieves 100% in suitable time with no extra area and wire length cost on design performances.

The average bit erasure probability of a binary linear code ensemble under maximum a-posteriori probability (MAP) decoding over binary erasure channel (BEC) can be calculated with the average support weight distribution of the ensemble via the EXIT function and the shortened information function. In this paper, we formulate the relationship between the average bit erasure probability under MAP decoding over BEC and the average support weight distribution for a binary linear code ensemble. Then, we formulate the average support weight distribution and the average bit erasure probability under MAP decoding over BEC for regular LDPC code ensembles.

This paper examines seasonal change of the true water area of Lake "Sakata" by using Polarimetric Synthetic Aperture Radar (POLSAR) image analysis. The true water area includes not only the body of water but also the water area under emerged-plants and/or floating-leave plants in the lake. Statistical POLSAR image analysis is carried out for both X- and L-band data, based on the three-component scattering power decomposition method, where the decomposed components are surface scattering, double-bounce scattering and volume scattering components. From the results of the image analysis for the L-band POLSAR data acquired by Pi-SAR system, it is found that strong double-bounce scattering can be observed at the vicinity of the boundary region between water area and the surrounding emerged-plants area in early and middle summer. This phenomenon is an important factor for environmental monitoring. To verify the generating mechanism of the double-bounce scattering, the Finite-Difference Time-Domain (FDTD) polarimetric scattering analysis is also executed for a simplified boundary model, which simulates the local boundary region around the lake and consists of lots of vertical thin dielectric pillars on a perfect electric conductor (PEC) plate or on a PEC and dielectric hybrid plate. Taking into account the polarimetric feature of the double-bounce scattering obtained by both the FDTD and POLSAR image analyses, one can distinguish the actual water area from the bush of the emerged-plants around the lake, even when the water area is concealed by emerged-plants and/or floating-leave plants. Consequently, it is found that by using the proposed approach, one can estimate the true water area seasonal change for the lake and the surrounding wetland.

The transmit power of Ultra Wideband (UWB) is limited in short range communications to avoid the interference with existing narrow-band communication systems. Since this limits UWB communication range, this paper proposes a novel relay scheme that uses shared frequency repeaters for impulse UWB signal relay to improve system range. After considering possible problems with the repeater, in particular the coupling interference between the input and output and relay-delay, a switching control method is proposed that offers short relay-delay and suppresses the coupling interference at the repeaters. With respect to the proposed relay scheme, Pulse-Position-Modulation (PPM) UWB-based signal relay is evaluated by analyzing its BER performance using the point-to-point transmission link model.

The possibility of using three kinds of new type composite materials as material for high speed sliding contacts was investigated. The results of this investigation were compared with the results of the low speed tests that were reported earlier. As a result of the above, it was discovered that for high speed rotation in the range from 0.014 m/s to 2 m/s, the order of merit did not significantly change. Based on this, it was concluded that if solid lubricant is effectively supplied to the sliding surface, the influence by frictional heat generated by high speed is slight. Of the three kinds of composite material, it was clarified that composite material (CMML-1) had the lowest contact resistance and Composite Material (CMML-3) had the lowest maximum frictional coefficient of friction. 'CM' and 'ML' are initialisms for 'Composite Material' and 'Material of Lubrication' respectively. The number that is attached to the material name is a numeric value that was set by this laboratory.

A persistent current switch (PCS) is used for superconducting applications, such as superconducting magnetic energy storage (SMES) system. The authors have proposed a mechanical switch of Y-Ba-Cu-O (YBCO) bulk as a mechanical PCS. In previous study, the authors have successfully reduced a residual resistance by depositing with metal on contact surface. This paper focused on a current carrying area (called a-spot) on contact surface and presented an effect of deposited metal on electrical contact characteristics in order to clear the contact mechanism. As the results of experiments and simulation using FEM, it became clear that it was effective for reducing the residual resistance from a view point of increasing the a-spot by depositing with metal.

This paper investigates the use of the affine transformation matrix when employing principal component analysis (PCA) to compress the data of 3D animation models. Satisfactory results were achieved for the common 3D models by using PCA because it can simplify several related variables to a few independent main factors, in addition to making the animation identical to the original by using linear combinations. The selection of the principal component factor (also known as the base) is still a subject for further research. Selecting a large number of bases could improve the precision of the animation and reduce distortion for a large data volume. Hence, a formula is required for base selection. This study develops an automatic PCA selection method, which includes the selection of suitable bases and a PCA separately on the three axes to select the number of suitable bases for each axis. PCA is more suitable for animation models for apparent stationary movement. If the original animation model is integrated with transformation movements such as translation, rotation, and scaling (RTS), the resulting animation model will have a greater distortion in the case of the same base vector with regard to apparent stationary movement. This paper is the first to extract the model movement characteristics using the affine transformation matrix and then to compress 3D animation using PCA. The affine transformation matrix can record the changes in the geometric transformation by using 44 matrices. The transformed model can eliminate the influences of geometric transformations with the animation model normalized to a limited space. Subsequently, by using PCA, the most suitable base vector (variance) can be selected more precisely.

In this paper, a new operational amplifier is presented that improves the specifications such as dc gain, common mode rejection ratio. To obtain these improvements, we have used the two important concepts of feedback and bulk amplification.

Recently, the superimposed pilot channel estimation has attracted attention for wireless communications, where the pilot symbol sequence is superimposed on a data symbol sequence and transmitted together, and thus there is no drop in information rate. In the superimposed pilot channel estimation, the receiver correlates the received symbol sequence with the pilot symbol sequence, and obtains the channel estimate. However, the correlation between the pilot symbol sequence and the data symbol sequence deteriorates the channel estimation accuracy. In particular, the channel estimation accuracy of the superimposed pilot channel estimation scheme is significantly deteriorated in MIMO systems, because the pilot symbol power of each transmit antenna to the total transmit power of all transmit antennas becomes smaller as the number of transmit antennas increases. On the other hand, it has been well known that the SAGE algorithm is an effective method for channel estimation and data detection. This algorithm is particularly effective in MIMO systems, because the operation of this algorithm can cancel the interference from other transmit antennas. In this paper, we evaluate the performance of the SAGE algorithm for channel estimation and data detection using superimposed pilot channel estimation in MIMO systems. From the results of computer simulations, we show that the system using the SAGE algorithm with superimposed training can achieve the good BER performances by using the SAGE algorithm with iteration.

The extened Kalman filter (EKF) and unscented Kalman filter (UKF) have been successively applied in particle filter framework to generate proposal distributions, and shown significantly improving performance of the generic particle filter that uses transition prior, i.e., the system state transition prior distribution, as the proposal distribution. In this paper we propose to use the Gauss-Newton EKF/UKF to replace EKF/UKF for generating proposal distribution in a particle filter. The Gauss-Newton EKF/UKF that uses iterated measurement update can approximate the optimal proposal distribution more closer than EKF/UKF, especially in the case of significant nonlinearity in the measurement function. As a result, the Gauss-Newton EKF/UKF is able to generate and propagate the proposal distribution for each particle much better than EKF/UKF, thus further improving the performance of state estimation. Simulation results for a nonlinear/non-Gaussian time-series demonstrate the superior estimation accuracy of our method compared with state-of-the-art filters.