The frequency regions and spectral features that can be used to measure the perceived similarity and continuity of voice quality are reported here. A perceptual evaluation test was conducted to assess the naturalness of spoken sentences in which either a vowel or a long vowel of the original speaker was replaced by that of another. Correlation analysis between the evaluation score and the spectral feature distance was conducted to select the spectral features that were expected to be effective in measuring the voice quality and to identify the appropriate speech segment of another speaker. The mel-frequency cepstrum coefficient (MFCC) and the spectral center of gravity (COG) in the low-, middle-, and high-frequency regions were selected. A perceptual paired comparison test was carried out to confirm the effectiveness of the spectral features. The results showed that the MFCC was effective for spectra across a wide range of frequency regions, the COG was effective in the low- and high-frequency regions, and the effective spectral features differed among the original speakers.

In remote control, efficient compression or representation of control signals is essential to send them through rate-limited channels. For this purpose, we propose an approach of sparse control signal representation using the compressive sampling technique. The problem of obtaining sparse representation is formulated by cardinality-constrained 2 optimization of the control performance, which is reducible to 1-2 optimization. The low rate random sampling employed in the proposed method based on the compressive sampling, in addition to the fact that the 1-2 optimization can be effectively solved by a fast iteration method, enables us to generate the sparse control signal with reduced computational complexity, which is preferable in remote control systems where computation delays seriously degrade the performance. We give a theoretical result for control performance analysis based on the notion of restricted isometry property (RIP). An example is shown to illustrate the effectiveness of the proposed approach via numerical experiments.

This paper proposes a direction-of-arrival (DOA) estimation method of multiple speech sources from a stereophonic mixture in an underdetermined case where the number of sources exceeds the number of sensors. The method relies on the sparseness of speech signals in time-frequency (T-F) domain representation which means multiple independent speakers have a small overlap. At first, a selection of T-F cells bearing reliable spatial information is proposed by an introduced reliability index which is defined by the estimated interaural phase difference at each T-F cell. Then, a statistical error propagation model between the phase difference at T-F cell and its consequent DOA is introduced. By employing this model and the sparseness in T-F domain the DOA estimation problem is altered to obtaining local peaks of probability density function of DOA. Finally the kernel density estimator approach based on the proposed statistical model is applied. The performance of the proposed method is assessed by conducted experiments. Our method outperforms others both in accuracy for real observed data and in robustness for simulation with additional diffused noise.

In this paper, we propose a novel path tracking control algorithm for an underactuated autonomous underwater vehicle (AUV). The underactuated AUV is controlled by the thrust force and the yaw torque: no sway thruster is used. To deal with this underactuated AUV problem in the path tracking, we introduce an approach angle which makes the AUV converge to the reference path. To design the path tracking controller, we obtain the vehicle's error dynamics in the body-fixed frame, and then design the path tracking controller based on the dynamic surface control (DSC) method. The proposed controller only needs the information of the position and the heading angle of the reference path. Some simulation results demonstrate the effectiveness of the proposed controller.

Zero-knowledge arguments allows one party to prove that a statement is true, without leaking any other information than the truth of the statement. In many applications such as verifiable shuffle (as a practical application) and circuit satisfiability (as a theoretical application), zero-knowledge arguments for mathematical statements related to linear algebra are essentially used. Groth proposed (at CRYPTO 2009) an elegant methodology for zero-knowledge arguments for linear algebraic relations over finite fields. He obtained zero-knowledge arguments of the sub-linear size for linear algebra using reductions from linear algebraic relations to equations of the form z=x*'y, where x, y ∈ Fnp are committed vectors, z ∈ Fp is a committed element, and *': FnpFnpFp is a bilinear map. These reductions impose additional rounds on zero-knowledge arguments of the sub-linear size. The round complexity of interactive zero-knowledge arguments is an important measure along with communication and computational complexities. We focus on minimizing the round complexity of sub-linear zero-knowledge arguments for linear algebra. To reduce round complexity, we propose a general transformation from a t-round zero-knowledge argument, satisfying mild conditions, to a (t-2)-round zero-knowledge argument; this transformation is of independent interest.

No nontrivial optimal sets of frequency-hopping sequences (FHSs) of period 2(2n-1) for a positive integer n ≥ 2 have been found so far, when their frequency set sizes are less than their periods. In this paper, systematic doubling methods to construct new FHS sets are presented under the constraint that the set of frequencies has size less than or equal to 2n. First, optimal FHS sets with respect to the Peng-Fan bound are constructed when frequency set size is either 2n-1 or 2n. And then, near-optimal FHS sets with frequency set size 2n-1 are designed by applying the Chinese Remainder Theorem to Sidel'nikov sequences, whose FHSs are optimal with respect to the Lempel-Greenberger bound. Finally, a general construction is given for near-optimal FHS sets whose frequency set size is less than 2n-1. Our constructions give new parameters not covered in the literature, which are summarized in Table1.

Keith Salvin presented a key exchange protocol using matrices in the general linear group, GL(r,Zn), where n is the product of two distinct large primes. The system is fully specified in the US patent number 7346162 issued in 2008. In the patent claims, it is argued that the best way to break this system is to factor n. Furthermore, for efficiency reasons, it is suggested to use r=2. In this letter, we show that this cryptosystem can be easily broken by solving a set of consistent homogeneous r2 linear equations in 2r unknowns over Zn.

The reduction in the gate length of the current devices to 65 nm causes their I-V characteristics to depart from the traditional MOSFETs. As a result, manufacturing of new efficient devices in nanoscale is inevitable. The fundamental properties of the metallic and semi-conducting carbon Nanotubes (CNTs) make them alternatives to the conventional silicon-based devices. In this paper an ultra high-speed and energy-efficient full adder is proposed, using Carbon Nanotube Field Effect Transistor (CNFET) in nanoscale. Extensive simulation results using HSPICE are reported to show that the proposed adder consumes lower power, and is faster compared to the previous adders.

In this paper, a high-throughput debloking filter is presented for H.264/AVC standard, catering video applications with 4 K2 K (40962304) ultra-definition resolution. In order to strengthen the parallelism without simply increasing the area, we propose a luma-chroma parallel method. Meanwhile, this work reduces the number of processing cycles, the amount of external memory traffic and the working frequency, by using triple four-stage pipeline filters and a luma-chroma interlaced sequence. Furthermore, it eliminates most unnecessary off-chip memory bandwidth with a highly reusable memory scheme, and adopts a “slide window” buffer scheme. As a result, our design can support 4 K2 K at 30 fps applications at the working frequency of only 70.8 MHz.

An OFDMA-based (Orthogonal Frequency Division Multiple Access-based) channel access scheme for dynamic spectrum access has the drawbacks of large PAPR (Peak to Average Power Ratio) and large ACI (Adjacent Channel Interference). To solve these problems, a flexible channel access scheme using an overlap FFT filter-bank was proposed based on single carrier modulation for dynamic spectrum access. In order to apply the overlap FFT filter-bank for dynamic spectrum access, it is necessary to clarify the performance of the overlap FFT filter-bank according to the design parameters since its frequency characteristics are critical for dynamic spectrum access applications. This paper analyzes the overlap FFT filter-bank and evaluates its performance such as frequency characteristics and ACI performance according to the design parameters.

We present a 3-D range map acquisition system using a gray-encoded time-multiplexing structured pattern. In this method the only information needed to reconstruct 3-D range map is whether the pixel is bright or not for the exposed structured patterns. A dedicated image sensor to capture the pattern consists of pixel parallel 1-bit A/D converter, in-pixel pattern address memory and column parallel digital pattern address readout circuit. This in-pixel memory and digital bit-parallel pattern address readout eliminate unnecessary readout of pattern data to enhance 3-D acquisition speed. We fabricated the image sensor in 0.18 µm CMOS and demonstrated up to 122 range map per second 3-D range map acquisition performance for 7 patterns with the average error of 3.2 mm under the condition of 10% pattern recognition error.

It is shown that it is feasible to apply 0.5-V 6-T SRAM cells in a 25-nm high-speed 1-Gb e-SRAM. In particular, for coping with rapidly reduced voltage margin as VDD is reduced, a boosted word-voltage scheme is first proposed. Second, Vt variations are reduced with repair techniques and nanoscale FD-MOSFETs to further widen the voltage margin. Third, a worst case design is developed, for the first time, to evaluate the cell. This design features a dynamic margin analysis and takes subthreshold current, temperature, and Vt variations and their combination in the cell into account. Fourth, the proposed scheme is evaluated by applying the worst-case design and a 25-nm planar FD-SOI MOSFET. It is consequently found that the scheme provides a wide margin and high speed even at 0.5 V. A 0.5-V high-speed 25-nm 1-Gb SRAM is thus feasible. Finally, to further improve the scheme, it is shown that it is necessary to use FinFETs and suppress and compensate process, voltage, and temperature variations in a chip and wafer.

The susceptibility of a static random access memory (SRAM) core against static and dynamic variation of power supply voltage is evaluated, by using on-chip diagnosis structures of memory built-in self testing (MBIST) and on-chip voltage waveform monitoring (OCM). The SRAM core of interest in this paper is a synthesizable version applicable to general systems-on-a-chip (SoC) design, and fabricated in a 90 nm CMOS technology. RF power injection to power supply networks is quantified by OCM. The number of resultant erroneous bits as well as their distribution in the cell array is given by MBIST. The frequency-dependent sensitivity reflects the highly capacitive nature of densely integrated SRAM cells.

Recently, there has been growing interest in opportunistically utilizing the 2.4 GHz ISM-band. Numerous spectrum occupancy measurements covering the ISM-band have been performed to analyze the spectrum usage. However, in these campaigns the verification of the correctness of the obtained occupancy values for the highly dynamic ISM-band has not been presented. In this paper, we propose and verify channel occupancy rate (COR) estimation utilizing energy detection mechanism with a novel adaptive energy detection threshold setting method. The results are compared with the true reference COR values. Several different types of verification measurements showed that our setup can estimate the COR values of 802.11 traffic well, with negligible overestimation. The results from real-time real-life measurements also confirm that the proposed adaptive threshold setting method enables accurate thresholds even in the situations where multiple interferers are present in the received signal.

In this paper, the author proposes an electromagnetic coupling fed inverted-FL antenna design. The inverted-FL antenna with a self-complementary structure has been reported as a way to achieve a constant impedance of 188 ohms without the need for a matching load, since the axially symmetric self-complementary antenna has constant impedance, even though it has a finite structure. This design has been realized by integrating an inverted-F antenna with a self-complementary structure for achieving a broadband characteristic and an inverted-L element for operation on a frequency lower than the minimum frequency of the antenna. The proposed antenna realizes a broadband characteristic without attaching the matching load and the impedance transformer to match 50 ohms. The impedance transformer necessary for the inverted-FL antenna with a self-complementary structure is removed by using an electromagnetic coupling feed structure. This antenna, which has a volume of 101045 mm3, obtained broadband and multi-band characteristics covering the GSM850/GSM900/DCS/PCS/UMTS2100/UMTS2600 bands and the 2.5 G/3.5 G bands for Mobile-WiMAX in simulation and measurement.

Mobility Robustness Optimization (MRO) is one of the most important goals in LTE-Advanced Self-Organizing Networks (SON). Seamless handover in femtocell network is urgent and challenging, which has not been paid enough attention. Handover decision parameters, such as Time-To-Trigger (TTT), Hysteresis, Cell Individual Offset (CIO), have great effect on mobility performance, which may lead to Radio Link Failures (RLFs) and Unnecessary Handover. This letter proposes a handover parameters optimization approach based on Ant Colony Algorithm in the femtocell networks. The simulation result shows that the proposed scheme has a better performance than the fixed parameters method.

We propose a distributed node selection (DNS) scheme that guarantees quality of service (QoS) of the scalable video broadcasting system over wireless channels. The proposed DNS scheme chooses the destination node based on the SVC layer information, and it selects the best relay from a set of competing candidate nodes by considering two factors: 1) wireless channel conditions between destination and relay candidates and 2) scalable video's layer information. In simulations, the performance of the proposed scheme in terms of quality gains, complexity (overhead) and applicability was examined.

This paper presents a precise characterization of high-frequency characteristics of intrinsic channel of FinFET. For the de-embedding of the parasitics attached to the source, drain and gate terminals, it proposes special calibration patterns which can place the reference surface just beside the intrinsic part of the FinFET. It compares the measured S parameter data up to 40 GHz with the device simulation and shows good matching. The experimental data of the through pattern also confirms the accuracy of the de-embedded parasitics and extracted intrinsic part of FinFET.

A small-sized leakage-controlled gated sense amplifier (SA) and relevant circuits are proposed for 0.5-V multi-gigabit DRAM arrays. The proposed SA consists of a high-VT PMOS amplifier and a low-VT NMOS amplifier which is composed of high-VT NMOSs and a low-VT cross-coupled NMOS, and achieves 46% area reduction compared to a conventional SA with a low-VT CMOS preamplifier. Separation of the proposed SA and a data-line pair achieves a sensing time of 6 ns and a writing time of 0.6 ns. Momentarily overdriving the PMOS amplifier achieves a restoring time of 13 ns. The gate level control of the high-VT NMOSs and the gate level compensation circuit for PVT variations reduce the leakage current of the proposed SA to 2% of that without the control, and its effectiveness was confirmed using a 50-nm test chip.