In this paper, we propose a flexible gaze detection method using single PTZ (Pan-Tilt-Zoom) camera. In this method, a PTZ camera traces user's face and measures position of their viewing point, so they do not need to fix their head in front of camera. Furthermore, to realize accurate gaze detection, we employ elliptical iris template matching. To reduce calculation amount of iris template matching, we get rough gaze direction by simple method on ahead to decide ellipse shape. In this paper, we also adapt to variation of facial orientations, which will affect to detect viewing position and gaze direction. After several experiments, we examine accuracy of gaze detection and head tracking ability of this system.

As hardware platforms increase in computation capability, multiple filter coefficient adaptations between two neighboring input signals can be realized to achieve a high convergence rate. This study explores the data-reusing scheme based on the Normalized Least Mean Squared (NLMS) algorithm. Moreover, the impacts of the reusing times and input signal vector's variance to the convergence rate and misadjustment of an adaptive filter are theoretically derived and analyzed. A large number of reusing times was found to raise the convergence rate but also increase misadjustament, while a high variance of an input vector was found to lower misadjustment and expedite the convergence rate. To reduce computational complexity of the data-reusing scheme, this study develops the Fast Data-Reusing NLMS (FDRNLMS) algorithm. The proposed FDRNLMS requires minimal computation for the adaptation scaling factor, and only requires two more multiplication operations than NLMS in calculating each filter output. Additionally, the computation complexity of this FDRNLMS is independent of the number of reusing times. Therefore, the FDRNLMS proposed herein is superior to the NLMS and Least Mean Squared (LMS) algorithms using conventional data-reusing schemes which have computation complexity proportional to the number of reusing times.

A waveguide-based surface plasmon resonance (SPR) sensor with an adsorbed layer is analyzed using the beam-propagation method. For two-dimensional (2-D) models, numerical results show that the change in thickness of the adsorbed layer placed on the metal leads to a significant shift of the maximum absorption wavelength. Through eigenmode analysis, the maximum absorption wavelength is found to be consistent with the cutoff wavelength of the second-order surface plasmon mode. The designed 2-D sensor shows an absorption wavelength shift from 0.595 to 0.603 µm, when the analyte refractive index is increased from 1.330 to 1.334. After a basic investigation using the 2-D models, we next study 3-D models. When the metal with the absorbed layer is wide enough to cover the core region, the 3-D results are similar to the 2-D results. However, as the metal width is reduced, the absorption wavelength shifts toward a shorter wavelength and the sensitivity to the refractive index change degrades gradually. The degradation of the sensitivity is considerable when the metal width is narrower than the core width. As a result, the metal width of the practical SPR sensor should be slightly wider than the core width so as to maintain the sensitivity corresponding to that obtained for the 2-D model.

In this paper, we evaluated the characteristics of the magnetic core loop antenna that is used to receive long wave radio signals for time standards. To evaluate the receiving sensitivity of the antenna, we calculated the antenna factor of the magnetic core loop antenna by combining a magnetic field simulation and a circuit simulation. The simulation results are in good agreement with the results obtained from the experiments. We then investigated the optimization of the antenna shape, and showed the relation between the shape of the magnetic core and the receiving sensitivity.

In this paper, we propose a new method for detecting label-free T4-DNA molecules quantitatively using a surface plasmon resonance (SPR) technique on a gold thin film. We used a solution that dissolved T4-DNA molecules in pure water, and examined the relationship between DNA concentration change and SPR angle change in the solution. As a result, it was confirmed that the SPR angle change increased with increasing DNA concentration change. Therefore, it was feasible to detect the DNA concentration change using the SPR technique. Furthermore, to examine and detect a single or a few DNA molecule, we tried to fabricate an SPR chip in which SPR area is narrowed so that it has the same effect as focusing the beam. To narrow the SPR area, we decreased the area of gold thin film in this chip, and, to reflect light from only the area of gold thin film, the area without a gold thin film was micromachined to increase its unevenness for the reduction of light reflection. By the above-mentioned method, we examined the possibility of detecting a label-free DNA molecule using the SPR technique.

This letter proposes a robust detection scheme of orthogonal space-time block codes that face very fast fading channels. The proposed detection scheme employs a QR decomposition on the channel matrix and minimizes noise enhancement and impact of channel estimation errors which occur in a conventional detection scheme. It is shown by simulations that the proposed detection scheme outperforms the conventional detection scheme when the channel fading is very fast.

This paper studies the reduction among cyptographic functions. Our main result is that the prime factoring function IF does not reduce to the certified discrete logarithm function modulo a prime nor its variant with respect to some special reducibility, i.e. the range injection reducibility, under the assumption that the Heath-Brown conjecture is true and IFPF. Since there is no known direct relationship between these functions, this is the first result that could separate these functions. Our approach is based on the notion of the preimage functions.

A lithium niobate (LiNbO3)/silicon (Si) hybrid structure has been developed by the surface-activated bonding of LiNbO3 chips with gold (Au) thin film to Si substrates with patterned Au film. After organic contaminants on the Au surfaces were removed using argon radio-frequency plasma, Au-to-Au bonding was carried out in ambient air. Strong bonding at significantly low temperatures below 100 without generating cracks has been demonstrated.

We propose a Fault-Tolerant Object Group framework that provides group management and fault-tolerance services for consistency maintenance and state transparency as well. Through a virtual home-network simulation, we validate that the FTOG framework supports both of the reliability and the stability of the distributed home-network systems.

In this letter, efficient two-dimensional (2-D) fast algorithms for realizations of 88 forward and inverse integer transforms in H.264/AVC fidelity range extensions (FRExt) are proposed. Based on matrix factorizations with Kronecker product and direct sum operations, efficient fast 2-D 88 forward and inverse integer transforms can be derived from the one-dimensional (1-D) fast 88 forward and inverse integer transforms through matrix operations. The proposed fast 2-D 88 forward and inverse integer transform designs don't require transpose memory in hardware realizations. The fast 2-D 88 integer transforms require fewer latency delays and provide a larger throughput rate than the row-column based method. With regular modularity, the proposed fast algorithms are suitable for VLSI implementations to achieve H.264/AVC FRExt high-profile signal processing.

Software defined radio, which uses reconfigurable signal processing devices, requires the determination of multiple unknown parameters to realize the potential capabilities of adaptive communication. Evolutional algorithms are optimal multi dimensional search techniques, and are well known to be effective for parameter determination. This letter proposes an evolutional algorithm for learning the mobile time-varying channel parameters without any specific assumption of scattering distribution. The proposed method is very simple to realize, but can provide precise channel estimation results. Simulations of an OFDM system show that for an example of OFDM communication under the time-varying fading channel, the proposed learning method can achieve the better BER performance.

In this paper, we propose an on-line e-coin system with four parties: Consumer, Merchant, Bank and Issuer. The proposed system not only circulates anonymous e-coins but also protects the profits of the Merchant and the Consumer during a transaction. An e-coin, consisting of a secret value c and a public value c'=h(c) where h() is a secure one-way hash function with collision resistant property, is generated by its owner. The public value of a legal e-coin is published on the bulletin board of Issuer. Only the owner who releases the secret values of the published e-coins can spend money. Instead of Bank, Issuer has to be on-line to verify and replace the public values of the Consumer's e-coins with the Merchant's while the Consumer pays money to the Merchant in a transaction. Such a replacement represents that the coins are passed from one person to another.

This paper describes a flexible strategy to generate candidate answers for factoid questions in Question Answering (QA) systems. Most QA systems have predefined the conceptual categories for candidate answers. But if the conceptual category of answers to any question is not prepared in the QA system, it is hard to extract correct answers to that question. Therefore, we propose an extraction method for IS-A relation patterns which describe relations between the nominal target concepts of question and candidate answers. The extracted IS-A relation patterns can be used for questions with an unexpected target concept.

In this letter, we suggest a noise estimation method which can be applied for speech enhancement in various noise environments. The proposed method consists of the following two main processes to analyze and estimate efficiently the noise from the noisy speech. First, a least-squares line is used, which is obtained by applying coefficient magnitudes in node with a uniform wavelet packet transform to a least squares method. Next, a differential forgetting factor and a correlation coefficient per subband are applied, where each subband consists of several nodes with the uniform wavelet packet transform. In particular, this approach has the ability to update noise estimation by using the estimated noise at the previous frame only instead of employing the statistical information of long past frames and explicit nonspeech frames detection consisted of noise signals. In objective assessments, we observed that the performance of the proposed method was better than that of the compared methods. Furthermore, our method showed a reliable result even at low SNR.

Reconfigurable devices are expected to be utilized in such mission-critical fields as space development and undersea cables, because system updates and pseudo-repair can be achieved remotely by reconfiguring. However, conventional reconfigurable devices suffer from memory-bit upset caused by charged particles in space which results in fatal system problems. In this paper, we propose an architecture of a fault-tolerant reconfigurable device. The proposed device is divided into "autonomous-repair cells" with embedded control circuits. The autonomous-repair cell proposed in this paper is based on error detection and correction (EDAC) and uses hardware and time redundancy. From evaluation, it is shown that the proposed architecture achieves sufficient reliability against configuration memory upset. Trade-offs between performance and cost are also analyzed.

DS-CDMA systems employing long-period PN sequences are becoming a widespread standard of wireless communication systems. However, fast acquisition of long-period PN sequences at a low hardware cost is conventionally a difficult problem. This paper examines a recently proposed fast acquisition algorithm for a class of PN sequences, which includes m and GMW sequences as special cases, under conditions of unknown received RF phase and chip boundary timing. The result shows that under low input (chip) SNR and the required delay estimation accuracy of Tc/Δ, Δ=2,3,…, the mean acquisition time can be considerably reduced compared to other known representative acquisition schemes. Its fast acquisition capability is based on a decomposition of long PN sequences into a number of short ones and achieves a significantly reduced code phase uncertainty of acquisition at relatively small hardware cost, estimated as 2/3 of the equivalent parallel correlators system. It can be applied as a (part of) acquisition scheme of a DS-CDMA system instead of a slow sliding correlator or a costly matched filter schemes.

In situ observation of the adsorption process and reduction behavior of hemoglobin adsorbed on a bare glass surface was studied using slab optical waveguide (SOWG) spectroscopy. The peak position of the absorption band of hemoglobin adsorbed on the glass surface was almost the same as that of hemoglobin in solution. This result agrees with results previously reported by our group. The adsorbed hemoglobin molecules were also reduced by sodium dithionite solution. The adsorbed hemoglobin molecules still maintained their function in this experimental condition.

Wireless communications technology continues to change and yield new standards for satisfying the user demands. As a result, multiple standards coexist and wireless communications systems supporting different air interfaces cannot interact with one another. Software-defined radio is regarded as the most promising solution to cope with this problem. In this paper, we discuss the design considerations of SDR systems from a base station point of view and propose new architecture which meets the inherent requirements of SDR platform. We then introduce hardware/software of SDR platform we accomplished on the basis of the new architecture. In addition, the results of basic transmission and receiving performance are presented to prove the feasibility of the proposed platform as a base station.

A new transmission line structure is presented in this work for advanced CMOS processes. This structure has a high quality factor and low attenuation. It allows slow-waves to propagate which results in low dispersion for a given characteristic impedance. It is also designed to satisfy the stringent density requirements of advanced CMOS processes. A model is developed to characterize this structure by analyzing the physical current flowing in the substrate and the shield structure. Test structures were fabricated using CMOS 90 nm process technology with measurements made up to 110 GHz using a transmission-reflection module on a network analyzer. The results correspond well to the proposed model.

We investigate selection transmit multi-input multi-output systems where only a single transmit antenna is selected for the transmission and multiple receive antennas are employed for maximal ratio combining. Antenna selection is performed by a generalized selection criterion based on the ordinal number of the strength of the received signal-to-noise ratio.