This paper addresses the problem of estimating 3-D motion of a rigid object from a sequence of monocular 2-D images. The surface of object is assumed to be modeled with several patches, each of which is expressed by an implicit equation. The proposed method estimates the pose (i.e., the location and orientation) of object that corresponds to each image in the sequence: The sequence of the estimated poses gives the motion of the object. The estimation is done by solving a system of equations, each of which is typically an algebraic equation of low degree, that is derived from the expressions of the surface patches and image contours data: so the method does not require establishing the correspondence between successive two frames in the image sequence or computing optic flow. Allowing several-patch models for objects enables the proposed approach to deal with a great variety of objects. The paper includes a numerical example, where our aproach has been applied to a polyhedral object modeled with several patches.

For the dependent protocols to perform the server-aided RSA secret computation, the damage caused by the active attacks is greater than that by the passive attacks. Though there are two dependent proposed protocols against active attacks, the cost of the two protocols is still high. In this paper, we propose two efficient dependent protocols. Even considering the low cost of these two protocols, they can also guard against the proposed active attacks.

We have studied the performances of several types of vortex flow transistors including prototype flux flow transistors (FFTs), nanobridge vortex flow transistors (NBVFTs) based on a parallel array of nanobridges, planar Josephson vortex flow transistors (planar JVFTs) based on a parallel array of grain boundary Josephson junctions, and JVFTs with a stacked structure (stacked JVFTs). The NBVFTs had considerably higher magnetic field sensitivity and shorter response time than the FFTs. A flux-to-voltage transfer function V/φ of 2.6 m V/φo and a modulation depth of 0.5 mV were obtained for the NBVFT composed of 2 nanobridges, while the current gain was small. The temperature dependence of the device parameters (the dynamic resistance and the inductance) suggests that the surface barrier to the Abrikosov vortex entry into the nanobridge strongly contributes to the relatively large V/φ values. The response time of the nanobridge is estimated to be 5 ps. On the other hand, the JVFTs showed large current gains because of the small kinetic inductance of the Josephson junction. The planar JVFT composed of 3 Josephson junctions with an asymmetrical geometry showed a current gain of 2.2 at 4.2 K. Also, the stacked JVFT showed the current gain of 2.0, while the maximum value of V/φ was 210 µV/φo. The mutual inductance between the control line and the superconducting loop within the transistor was enhanced in the stacked JVFT. This enhancement may yield a short response time compared to that of the planar JVFT. When we apply these vortex flow transistors, we should take account of the properties peculiar to each transistor.

For Nakagami-Rice fading environment which seems to become a principle propagation environment in the next generation wideband and high-capacity mobile systems such as personal communications, we have previously proposed an approximated evaluation scheme for wideband digital transmission characteristics such as errors due to intersymbol interference of multipath waves. We called the scheme 'Equivalent Transmission-Path (ETP) Model.' In this paper, through a discussion about more general equivalent propagation channel expressions, we clarify a theoretical foundation of the ETP model and extend the model to have an ability of expression of instantaneous fading condition varying with time. Also the appropriateness of the instantaneous expression is examined by a computer simulation analysis. Based on this model, statistics of link quality and service availability in Nakagami-Rice fading environments are discussed.

For direct sequence spread spectrum systems, the performance of PN sequence acquisition can be significantly affected if data modulation is present. However, the data modulation often exists during the reacquisition of a PCS radio channel. This study proposes and analyzes two shemes which are designed to improve acquisition process for PN sequence under data modulation. Both designs are based upon a PN acquisition receiver with parallel I-Q matched filters. The first scheme employs a serial search strategy with verification mode. The second scheme, which is still based upon the same parallel acquisition receiver, employs the parallel search strategy. We show that the second scheme is capable of providing faster acquisition under data modulation than the first serial search scheme using the same number of I-Q matched filter. We believe it should become a very good alternative for the acquisition of data modulated PN sequences in personal communications.

The 4th harmonics of a Nd:YAG laser beam (266 nm) is applied to fabricate highly oriented Y1Ba2Cu3O7-δ -SrTiO3-Y1Ba2Cu3O7-δ multilayer structures. It has been shown that the emission temperature of a film surface will change during deposition, depending on deposition conditions, even though the heater temperature is constant. The change of substrate temperature is strongly correlated to film characteristics such as critical temperature, c-axis length, and resistivity. The insitu monitoring of the substrate temperature is useful for obtaining high-quality Y1Ba2Cu3O7-δ films reproducibly. It is also shown that a SrTiO3 layer prevents oxygen restoration in a Y1Ba2Cu3O7-δ underlayer. The relationship between oxygen deficiency and the annealing conditions is studied.

In the weakly coupled grain model which has been proposed to explain the residual surface resistance in high-Tc superconducting polycrystalline thin films, the superconducting polycrystalline thin films is described as a network of superconducting grains coupled via Josephson junctions. In order to evaluate this model we have fabricated the coplanar waveguide resonator using c-axis oriented YBa2Cu3Ox Thin Films and measured the residual surface resistance. The experimental results are in good agreement with theoretical prediction.

Hot-carrier degradation of voltage controlled oscillator (VCO) was investigated by a reliability simulator known as BERT. The appropriate monitor of VCO frequency degradation shifts from the saturated drain current of an N MOSFET to linear drain current with an increase in VCO input voltage. The degradation of the VCO drastically increases with a small reduction in initial oscillation frequency. These results imply the need for an appropriate reliability margin around the standard operating point as well as a performance margin, which cannot be achieved by using conventional drain current monitors.

This paper compares the performance of an indoor cellular system in terms of capacity and channel assignment delay for different Dynamic Channel Assignment (DCA) and Fixed Channel Assignment (FCA) schemes. We refer to specific group of DCAs, namely Channel Segregation and Reuse Partitioning (RP). Our main concern is to show that these DCA schemes offer better performance than FCA. Since the structure and floor layout of a building will have a major influence on the propagation and hence on the cell shape, a path loss simulator is developed for predicting the path loss which is used in evolving base station layouts. Computer simulation, based on Monte Carlo method, is carried out using the path loss values and the base station layouts. The results indicate that increased traffic capacity can be achieved with all DCAs in comparison with FCA. The highest capacity and a shorter channel assignment delay are delivered by Self-Organized Reuse Partitioning DCA scheme.

This paper considers the evaluation of the acquisition performance for an access channel preamble based on the random access procedure of direct sequence code division multiple access (DS/CDMA) reverse link. The parallel acquisition technique that employs the single-dwell and multiple-dwell (double-dwell) detection schemes is investigated. The acquisition performance for two detection schemes is compared in terms of the acquisition probablity and the mean acquisition time. The parallel acquisition is done by a bank of N parallel I/Q noncoherent correlators. Expressions on the detection, false alarm, and miss probabilities of the single-dwell and multiple-dwell (double-dwell) detection schemes are derived for the multiple H1 cells and multipath Rayleigh fading channel. Comparing the single-dwell detection scheme with the multiple-dwell (double-dwell) detection scheme in the case of employing the parallel acquisition technique in the reverse link, the numerical results show that the single-dwell detection scheme provides a better performance.

The performance of APP (a posteriori probability) decoding algorithm which is well known as a soft decision decoding algorithm for majority logic decodable codes is further improved by iterating the algorithm one or more times. This letter shows that there exists the optimal non-zero threshold value of the decision function that minimizes the decoded error rate in two-pass APP decoding though the optimal threshold value in one-pass APP decoding is zero.

M-ary orthogonal keying (MOK) systems under carrier frequency offset (CFO) are investigated. It is shown that spurious signals are introduced by the offset frequency components of spectrum after multiplication in correlation detection process, and some conditions on robust orthogonal signal sets are derived. Walsh function sets are found to be very weak against CFO, since they produce large spurious signals. As robust orthogonal signal sets against CFO, the rows of circulant Hadamard matrices are proposed and their error performanses are evaluated. The results show that they are good M-ary orthogonal signal sets in the presence of CFO.

ISM band has been approved for spread spectrum communication in radio LAN in Japan since December 1992. This frequency band extends from 2.474 GHz to 2.5 GHz with 26 MHz bandwide. In an indoor environment, the maximum observed delay spread is 100-200 ns in a room, it is too short to generate a selective fading, thus flat fading conditions are often observed. Serve as an alleviation, we propose a new system of multi-antenna in base station (BS) and single antenna in mobile station (MS). In this system, MS should have a simple structure for its small size and energy-saving.

We have developed a strato-mesospheric ozone monitoring system with a low noise SIS mixer, which receives 110.836 GHz millimeter-wave emission due to the rotational transition of ozone molecules (J=61,560,6). The system is completely standalone. We derived the altitude profile of ozone density between 25 km and 80 km from the observed spectrum. The receiver noise temperature was as low as 17 K (DSB), so that the altitude profile could be obtained every 3-10 minutes. The monitoring system can operate continuously over one year without any maintenance work, because it utilizes a 4 K closed cycle helium refrigerator and reliable Nb/AIOx/Nb SIS junctions. We used two acousto-optical spectrometers (AOSs) as real-time spectrometers because of their high resolution and simple construction. In an up-to-date system, one AOS would have a band-width of 65 MHz and the other, a band-width of 250 MHz with resolutions of 40 kHz and 250 kHz, respectively. A computer controls the entire system and is also used to analyze measured data. In this paper, we present the principles of system operation, the latest performance and the construction of the system, and some observed data.

In this paper, oscillation modes produced in a Josephson circuit and its application to digital systems are described. The analysis is performed using an analog simulator to model the Josephson junction, in addition to computer simulation. The experimental results concerning oscillation modes agree well with the simulation results. The main advantage of the mapping for the oscillation modes is that it allows understanding of the relationships among oscillation modes and circuit parameters at first sight. In addition, a novel application of nonlinear oscillation to digital systems is described.

The problem of test generation for VLSI circuits computationally requires prohibitive costs. Parallel processing on a multiprocessor system is one of available methods in order to speedup the process for such time-consuming problems. In this paper, we analyze the performance of parallel test generation for combinational circuits. We present two types of parallel test generation systems in which the communication methods are different; vector broadcasting (VB) and fault broadcasting (FB) systems, and analyze the number of generated test vectors, the costs of test vector generation, fault simulation and communication, and the speedup of these parallel test generation systems, where the two types of communication factors; the communication cut-off factor and the communication period, are applied. We also present experimental results on the VB and FB systems implemented on a network of workstations using ISCAS'85 and ISCAS'89 benchmark circuits. The analytical and experimental results show that the total number of test vectors generated in the VB system is the same as that in the FB system, the speedup of the FB system is larger than that of the VB, and it is effective in reducing the communication cost to switch broadcasted data from vectors to faults.

We study Lempel-Ziv-Yokoo algorithm [1, Algorithm 4] for universal data compression. In this paper, we give a simpler implementation of Lempel-Ziv-Yokoo algorithm than the original one [1, Algorithm 4] and show its asymptotic optimality for a stationary ergodic source.

We propose in this paper a systematic way for analyzing discrete event dynamic systems to classify faults and failures quantitatively and to find tolerable fault event sequences embedded in the system. An automated failure diagnosis scheme with respect to the nominal normal operating event sequences and the supervisory control for tolerable fault event sequences are presented. Moreover the supervisor failure diagnosis with respect to the tolerable fault event sequences is considered. Finally, a case study of plasma etching system is described.

Introducing a mathematical model of image noise, we formalize the problem of fitting a conic to point data as statistical estimation. It is shown that the reliability of the fitted conic can be evaluated quantitatively in the form of the covariance tensor. We present a numerical scheme called renormalization for computing an optimal fit and at the same time evaluating its reliability. We also present a scheme for visualizing the reliability of the fit by means of the primary deviation pair. Our method is illustrated by showing simulations and real-image examples.

This paper presents an O(mn log n) time algorithm for an approximate string matching problem, in which a pattern string may contain variable length don't care characters. This problem is important for searching DNA sequences or amino acid sequences.