This paper presents an efficient multi-service allocation scheme for the digital television terrestrial broadcasting systems in which the fixed service is modulated by orthogonal frequency division multiplexing and quadrature amplitude modulation (OFDM/QAM) with larger FFT size and the added mobile service is modulated by OFDM and offset quadrature amplitude modulation (OQAM) with smaller FFT size. The two different types of services share one 8MHz broadcasting channel. The isotropic orthogonal transform algorithm (IOTA) is chosen as the shaping filter for OQAM because of its isotropic convergence in time and frequency domain and the proper FFT size is selected to maximum the transmission capacity under mobile environment. The corresponding transceiver architecture is also proposed and analyzed. Simulations show that the newly added mobile service generates much less out-of-band interference to the fixed service and has a better performance under fast fading wireless channels.

The data rate of VLSI interconnections has been increasing according to the demand for high-speed operation of semiconductors such as CPUs. To realize high performance VLSI systems, high-speed data communication has become an important factor. However, at high-speed data rates, it is difficult to achieve accurate communication without bit errors because of inter-symbol interference (ISI). This paper presents high-speed data communication techniques for VLSI systems using Tomlinson-Harashima Precoding (THP). Since THP can eliminate the ISI with limiting average and peak power of transmitter signaling, THP is suitable for implementing advanced low-voltage VLSI systems. In this paper, 4-PAM (Pulse amplitude modulation) with THP has been employed to achieve high-speed data communication in VLSI systems. Simulation results show that THP can remove the ISI without increasing peak and average power of a transmitter. Moreover, simulation results clarify that multiple-valued data communication is very effective to reduce implementation costs for realizing high-speed serial links.

A top-k keyword query in relational databases returns k trees of tuples — where the tuples containing the query keywords are connected via primary key-foreign key relationships — in the order of relevance to the query. Existing works are classified into two categories: 1) the schema-based approach and 2) the schema-free approach. We focus on the former utilizing database schema information for more effective ranking of the query results. Ranking measures used in existing works can be classified into two categories: 1) the size of the tree (i.e., the syntactic score) and 2) ranking measures, such as TF-IDF, borrowed from the information retrieval field. However, these measures do not take into account semantic relevancy among relations containing the tuples in the query results. In this paper, we propose a new ranking method that ranks the query results by utilizing semantic relevancy among relations containing the tuples at the schema level. First, we propose a structure of semantically strongly related relations, which we call the strongly related tree (SRT). An SRT is a tree that maximally connects relations based on the lossless join property. Next, we propose a new ranking method, SRT-Rank, that ranks the query results by a new scoring function augmenting existing ones with the concept of the SRT. SRT-Rank is the first research effort that applies semantic relevancy among relations to ranking the results of keyword queries. To show the effectiveness of SRT-Rank, we perform experiments on synthetic and real datasets by augmenting the representative existing methods with SRT-Rank. Experimental results show that, compared with existing methods, SRT-Rank improves performance in terms of four quality measures — the mean normalized discounted cumulative gain (nDCG), the number of queries whose top-1 result is relevant to the query, the mean reciprocal rank, and the mean average precision — by up to 46.9%, 160.0%, 61.7%, and 63.8%, respectively. In addition, we show that the query performance of SRT-Rank is comparable to or better than those of existing methods.

In this paper, we propose a fully automatic method for extracting carotid artery contours from ultrasound images based on an active contour approach. Several contour extraction techniques have been proposed to measure carotid artery walls for early detection of atherosclerotic disease. However, the majority of these techniques require a certain degree of user interaction that demands time and effort. Our proposal automatically detects the position of the carotid artery by identifying blood flow information related to the carotid artery, and an active contour model is employed that uses initial contours placed in the detected position. Our method also applies a global energy minimization scheme to the active contour model. Experiments on clinical cases show that the proposed method automatically extracts the carotid artery contours at an accuracy close to that achieved by manual extraction.

Let T1,T2,...,Tk be spanning trees in a graph G. If, for any two vertices u,v of G, the paths joining u and v on the k trees are mutually vertex-disjoint, then T1,T2,...,Tk are called completely independent spanning trees (CISTs for short) of G. The construction of CISTs can be applied in fault-tolerant broadcasting and secure message distribution on interconnection networks. Hasunuma (2001) first introduced the concept of CISTs and conjectured that there are k CISTs in any 2k-connected graph. Unfortunately, this conjecture was disproved by Péterfalvi recently. In this note, we give a necessary condition for k-connected k-regular graphs with ⌊k/2⌋ CISTs. Based on this condition, we provide more counterexamples for Hasunuma's conjecture. By contrast, we show that there are two CISTs in 4-regular chordal rings CR(N,d) with N=k(d-1)+j under the condition that k ≥ 4 is even and 0 ≤ j ≤ 4. In particular, the diameter of each constructed CIST is derived.

The Piece in Hand method is a security enhancement technique for Multivariate Public Key Cryptosystems (MPKCs). Since 2004, many types of this method have been proposed. In this paper, we consider the 2-layer nonlinear Piece in Hand method as proposed by Tsuji et al. in 2009. The key point of this method is to introduce an invertible quadratic polynomial map on the plaintext variables to add perturbation to the original MPKC. An additional quadratic map allows the owner of the secret key to remove this perturbation from the system. By our analysis, we find that the security of the enhanced scheme depends mainly on the structure of the quadratic polynomials of this auxiliary map. The two examples proposed by Tsuji et al. for this map can not resist the Linearization Equations attack. Given a valid ciphertext, we can easily get a public key which is equivalent to that of the underlying MPKC. If there exists an algorithm that can recover the plaintext corresponding to a valid ciphertext of the underlying MPKC, we can construct an algorithm that can recover the plaintext corresponding to a valid ciphertext of the enhanced MPKC.

In this paper, compact reconfigurable wideband Inverted-F Antenna (IFA) elements are proposed for a Long Term Evolution (LTE) mobile terminal. The proposed inverted-F antenna has a very simple planar arrangement. A capacitive coupling feed strip is employed to modify the input impedance matching. A chip inductor is connected in series to the feeding point to realize the wideband property. The whole Multiple-Input Multiple-Output (MIMO) antenna system consists of two similar inverted-F antenna elements. Antenna element #1 has a wideband property with a 6-dB bandwidth from 0.74 to 0.9GHz. To further expand the bandwidth, antenna element #2 has a reconfigurable property through the use of a Positive Intrinsic-Negative (PIN) diode. Antenna element #2 has a 6-dB bandwidth from 0.74 to 0.84GHz when the PIN diode is on and from 0.79 to 0.9GHz when the PIN diode is off. Moreover, the proposed MIMO antenna has a low radiation-pattern-based envelope correlation coefficient (ECC), which is less than 0.15 over LTE bands 4, 5, 13, and 14.

A ferroelectric-based (FE-based) non-volatile logic is proposed for low-power LSI. Standby currents in a logic circuit can be cut off by using FE-based non-volatile flip-flops (NVFFs), and the standby power can be reduced to zero. The FE capacitor is accessed only when the power turns on/off, performance of the NVFF is almost as same as that of the conventional flip-flop (FF) in a logic operation. The use of complementarily stored data in coupled FE capacitors makes it possible to realize wide read voltage margin, which guarantees 10 years retention at 85 degree Celsius under less than 1.5V operation. The low supply voltage and electro-static discharge (ESD) detection technique prevents data destruction caused by illegal access for the FE capacitor during standby state. Applying the proposed circuitry in CPU, the write and read operation for all FE capacitors in 1.6k-bit NVFFs are performed within 7µs and 3µs with access energy of 23.1nJ and 8.1nJ, respectively, using 130nm CMOS with Pb(Zr,Ti)O3(PZT) thin films.

Since electromagnetic (EM) noise resulting from an arc discharge disturbs other electric devices, parameters on electromagnetic compatibility, as well as lifetime and reliability, are important properties for electrical contacts. To clarify the characteristics and the mechanism of the generation of the EM noise, the arc column and voltage fluctuations generated by slowly breaking contacts with external direct current (DC) magnetic field, up to 20,mT, was investigated experimentally using Ag$_{90.7{ m wt%}}$SnO$_{2,9.3{ m wt}%}$ material. Firstly the motion of the arc column is measured by high-speed camera. Secondary, the distribution of the motion of the arc and contact voltage are discussed. It was revealed that the contact voltage fluctuation in the arc duration is related to the arc column motion.

There has been increasing demand to research the measuring method to characterize the batch consistency of contact rivets. An automated test equipment has been described that makes it possible to measure the electrical contact resistance with high efficiency. The relationship between contact force and contact resistance during the loading and unloading process was measured explicitly using AgPd alloy, stainless steel and sapphire substrate material with Au coatings as sphere indenters separately. To explain the phenomena of contact resistance decreasing more slowly than the traditional theoretical results during loading, the indenter with coating and rivet are modeled by using the commercial FEM software COMSOL Multiphysics. Besides the constriction resistance, the transition region Au coating resistance and the bulk resistance of the substrate are deduced from the simulated current lines profiles and iso-potentials. The difference of electrical conductivity between indenter material and gold coating is the reason for the occurrence of the transition region.

In this paper, we study the feasibility of a batteryless wireless sensor supplied with energy by using microwave power transmission (MPT). If we perform co-channel operation of MPT and wireless local area networks (WLANs) for the sake of spectral efficiency, a time division method for MPT and WLAN communications is required to avoid serious interference from MPT to WLAN data transmissions. In addition, to reduce the power consumption of a sensor, the use of power-save operation of the sensor is desirable. We proposed a scheduling scheme that allocates time for MPT and WLAN communications. Specifically, in the proposed scheduling system, an energy source transmits microwave power to a sensor station except when the sensor station transmits data frames or receives beacon frames. In addition, in the proposed scheduling system, we force the remaining energy of the sensor station to converge to a maximum value by adjusting the time interval of data transmission from the sensor station such that the power consumption of the sensor station is reduced. On the basis of the proposition, we implemented a scheduling system and then confirmed that it performed successfully in the conducted experiments. Finally, we discussed the feasibility of the proposed scheduling scheme by evaluating the coverage and then showed that the scheduling scheme can be applied to closed space or room.

Binaural reproduction is one of the promising approaches to present a highly realistic virtual auditory space to a listener. Generally, binaural signals are reproduced using a set of headphones that leads to a simple implementation of such a system. In contrast, binaural signals can be presented to a listener using a technique called “transaural reproduction” which employs a few loudspeakers with crosstalk cancellation for compensating acoustic transmissions from the loudspeakers to both ears of the listener. The major advantage of transaural reproduction is that a listener is able to experience binaural reproduction without wearing any device. This leads to a more natural listening environment. However, in transaural reproduction, the listener is required to be still within a very narrow sweet spot because the crosstalk canceller is very sensitive to the listener's head position and orientation. To solve this problem, dynamic transaural systems have been developed by utilizing contact type head tracking. This paper introduces the development of a dynamic transaural system with non-contact head tracking which releases the listener from any attachment, thereby preserving the advantage of transaural reproduction. Experimental results revealed that sound images presented in the horizontal and median planes were localized more accurately when the system tracked the listener's head rotation than when the listeners did not rotate their heads or when the system did not track the listener's head rotation. These results demonstrate that the system works effectively and correctly with the listener's head rotation.

In mobile wireless sensor networks, coverage and energy are two significant factors determining network performance. When taking both factors into account, the challenges include how to select and migrate nodes to keep coverage quality, how to forecast and prevent potential coverage holes and how to use energy control in mobile networks. In this paper, we propose a new Coverage Maintenance and Energy Control (CMEC) algorithm to achieve and keep high coverage quality and energy efficiency. For CMEC, we provide a new cost metric for selecting migration nodes. Our simulation results confirm that our algorithm improves coverage performance and lifetime of network.

When ultra-high-frequency (UHF) method is applied in partial discharge (PD) detection for GIS, the propagation process and rules of electromagnetic (EM) wave need to be understood clearly for conducting diagnosis and assessment about the real insulation status. The preceding researches are mainly concerning about the radial component of the UHF signal, but the propagation of the signal components in axial and radial directions and that perpendicular to the radial direction of the GIS tank are rarely considered. So in this paper, for a 252,kV GIS with T-shaped structure (TS), the propagation and attenuation of PD-induced EM wave in different circumferential angles and directions are investigated profoundly in time and frequency domain based on Finite Difference Time Domain (FDTD) method. The attenuation rules of the peak to peak value (Vpp) and cumulative energy are concluded. By comparing the results of straight branch and T branch, the influence of T-shaped structure over the propagation of different signal components are summarized. Moreover, the new circumferential and axial location methods proposed in the previous work are verified to be still applicable. This paper discusses the propagation mechanism of UHF signal in T-shaped tank, which provides some referential significance towards the utilization of UHF technique and better implementation of PD detection.

Increased inductance values and contact resistance in connector contact surfaces due to degradation of connector contact performance have been reported. In particular, inductance increases while degradation remains minimal. We focus on slight loosening in which increased inductance values are observed without increased resistance values, and investigate the effect of loose connectors on transmission line coupling noise under such circumstances. We find a proportional relation between coupled noise current and frequency. Moreover, we find a proportional relation between the increased inductance value, which depends on the change in connector contact distribution, and the coupled noise current in the transmission line.

This paper presents a mechanism for detecting dynamic loop and procedure nesting during the actual program execution on-the-fly. This mechanism aims primarily at making better strategies for performance tuning or parallelization. Using a pre-compiled application executable machine code as an input, our mechanism statically generates simple but precise markers that indicate loop entries and loop exits, and dynamically monitors loop nesting that appears during the actual execution together with call context tree. To keep precise loop structures all the time, we monitor the indirect jumps that enter the loop regions and the setjmp/longjmp functions that cause irregular function call transfers. We also present a novel representation called Loop-Call Context Graph that can keep track of inter-procedural loop nests. We implement our mechanism and evaluate it using SPEC CPU2006 benchmark suite. The results confirm that our mechanism can successfully reveal the precise inter-procedural loop nest structures from all of SPEC CPU2006 benchmark executions without any particular compiler support. The results also show that it can reduce runtime loop detection overheads compared with the existing loop profiling method.

A new real-time sound field transmission system is presented. To construct this system, a large listening area needs to be reproduced at not less than a constant height. Additionally, the driving signals of the loudspeakers should be obtained only from received signals of microphones. Wave field reconstruction (WFR) filtering for linear arrays of microphones and loudspeakers is considered to be suitable for this kind of system. An experimental system was developed to show the feasibility of real-time sound field transmission using the WFR filter. Experiments to measure the reproduced sound field and a subjective listening test of sound localization were conducted to evaluate the proposed system. Although the reproduced sound field included several artifacts such as spatial aliasing and faster amplitude decay, the experimental results indicated that the proposed system was able to provide sound localization accuracy for virtual sound sources comparable to that for real sound sources in a large listening area.

We discuss the division of radio resources in the time and frequency domains for wireless local area network (WLAN) devices powered with microwave energy. In general, there are two ways to avoid microwave power transmission (MPT) from influencing data communications: adjacent channel operation of continuous MPT and WLAN data transmission and co-channel operation of intermittent MPT and WLAN data transmission. Experimental results reveal that, even when we implement these methods, several problems arise because WLAN devices have been developed without supposing the existence of MPT. One problem clarified in our experiment is that adjacent channel operation at 2.4GHz does not necessarily perform well owing to the interference from MPT. This interference occurs regardless of the frequency separation at 2.4GHz. The other problem is that intermittent MPT could result in throughput degradation owing to the data rate control algorithm and the association scheme of the WLAN. In addition, the experimental results imply that a microwave energy source and a WLAN device should share information on the timings of intermittent MPT and data transmission to avoid buffer overflow.

In this paper, we introduced a novel Kernel-Reliability-based K-Means (KRKM) clustering algorithm for categorizing an unknown dataset under noisy condition. Compared with the conventional clustering algorithms, the proposed KRKM algorithm will measure both the reliability and the similarity for classifying data into its neighbor clusters by the dynamic kernel functions, where the noisy data will be rejected by being given low reliability. The reliability for classifying data is measured by a dynamic kernel function whose window size will be determined by the triangular relationship from this data to its two nearest clusters. The similarity from a data item to its neighbor clusters is measured by another adaptive kernel function which takes into account not only the similarity from data to clusters but also that between its two nearest clusters. The main contribution of this work lies in introducing the dynamic kernel functions to evaluate both the reliability and similarity for clustering, which makes the proposed algorithm more efficient in dealing with very strong noisy data. Through various experiments, the efficiency and effectiveness of proposed algorithm have been confirmed.

This paper provides an overview of power line communication (PLC) applications, challenges and possible evolution. Emphasis is put on two relevant aspects: a) channel characterization and modeling, b) filter bank modulation for spectral efficient transmission. The main characteristics of both the indoor channel (in-home, in-ship, in-car) and the outdoor low voltage and medium voltage channels are reported and compared. A simple approach to statistically model the channel frequency response (CFR) is described and it is based on the generation of a vector of correlated random variables. To overcome the channel distortions, it is shown that filter bank modulation can provide robust performance. In particular, it is shown that the sub-channel spectral containment of filtered multitone modulation (FMT) can provide high notching capability and spectral efficiency. Reduced complexity can be obtained with a cyclic filter bank modulation approach that we refer to as cyclic block FMT modulation (CB-FMT) which still provides higher spectral flexibility/efficiency than OFDM.