This paper proposes an efficient fingerprint recognition algorithm combining phase-based image matching and feature-based matching. In our previous work, we have already proposed an efficient fingerprint recognition algorithm using Phase-Only Correlation (POC), and developed commercial fingerprint verification units for access control applications. The use of Fourier phase information of fingerprint images makes it possible to achieve robust recognition for weakly impressed, low-quality fingerprint images. This paper presents an idea of improving the performance of POC-based fingerprint matching by combining it with feature-based matching, where feature-based matching is introduced in order to improve recognition efficiency for images with nonlinear distortion. Experimental evaluation using two different types of fingerprint image databases demonstrates efficient recognition performance of the combination of the POC-based algorithm and the feature-based algorithm.

The safety and availability policies are very important in an access control system for ensuring security and success when performing a certain task. However, conflicts may arise between safety and availability policies due to their opposite focuses. In this paper, we address the problem of consistency checking for safety and availability policies, especially for the co-existence of static separation-of-duty (SSoD) policies with availability policies, which determines whether there exists an access control state that satisfies all of these policies. We present criteria for determining consistency with a number of special cases, and show that the general case and partial subcases of the problem are intractable (NP-hard) and in the Polynomial Hierarchy NPNP. We design an algorithm to efficiently solve the nontrivial size instances for the intractable cases of the problem. The running example shows the validity of the proposed algorithm. The investigation will help the security officer to specify reasonable access control policies when both safety and availability policies coexist.

Various observation models have been introduced into the object tracking community, and combining them has become a promising direction. This paper proposes a novel approach for estimating the confidences of different observation models, and then effectively combining them in the particle filter framework. In our approach, spatial Likelihood distribution is represented by three simple but efficient parameters, reflecting the overall similarity, distribution sharpness and degree of multi peak. The balance of these three aspects leads to good estimation of confidences, which helps maintain the advantages of each observation model and further increases robustness to partial occlusion. Experiments on challenging video sequences demonstrate the effectiveness of our approach.

In this letter, a novel 4-way X-band spatial power divider/combiner has been developed using a modified quasi-Yagi antenna transition. The divider has an insertion loss of less than 0.5 dB and a power balance of +/-0.8 dB over a bandwidth of 3.5 GHz in the X-band. A power combiner amplifier using this circuit and four MMIC amplifiers has been demonstrated with 84% combining efficiency. The obtained results show that the modified quasi-Yagi antenna is a suitable element to develop a broadband spatial power combiner.

This paper proposes a new overlay transmission system for wireless LAN with RTS/CTS exchange. Conventional timing synchronization schemes may fail in the presence of inter-system interference, because they have not been designed for overlay transmission. In the proposed system, a transmitter estimates the transmission timing of the next wireless LAN DATA frame, and then sends its DATA frame at almost the same time as the estimated transmission timing to easily establish timing synchronization at the receiver. Moreover, we employ a tapped delay line adaptive array antenna at both transmitter and receiver to effectively suppress interference due to overlay transmission in a rich multipath propagation environment. The frame error rate performances of the proposed system and the IEEE 802.11a wireless LAN are evaluated through computer simulations that assume an exponentially decaying 8-path non-line-of-sight fading channel and include a timing synchronization process. Simulation results demonstrate that the proposed system can achieve overlay transmission while avoiding interference in a rich multipath propagation environment.

Cooperative transmission protocols attract a great deal of attention in recent years as an efficient way to increase the capacity of multi-hop wireless networks in fading environments. In this paper, we propose and analyze a cooperative transmission method, called Cooperative-Aided Skipping multi-Hop protocol (CASH), for multi-hop wireless networks with Rayleigh fading environments. For performance evaluation, we compare and verify the results of the theoretical analysis with the results of simulations.

Proposed in this paper is a low power BIST architecture using the pattern mapping method based on the transition freezing method. The transition freezing method generates frozen patterns dynamically according to the transition tendency of an LFSR. This leads to an average power reduction of 60%. However, the patterns have limitations of 100% fault coverage due to random resistant faults. Therefore, in this paper, those faults are detected by mapping useless patterns among frozen patterns to the patterns generated by an ATPG. Throughout the scheme, 100% fault coverage is achieved. Moreover, we have reduced the amount of applied patterns, the test time, and the power dissipation.

A cooperative relaying system with transmission scheduling is investigated. Cooperative relaying is composed of multiple links because the source sends the data to more than one receiver, and the destination receives multiple data transmitted by more than one transmitter. Therefore, if the source can transmit the data when the channel gains of the links are high, it is not clear which channel gains should be high in order to achieve high spectral efficiency. In the present letter, the spectral efficiency of a cooperative relaying system is theoretically derived under the assumption that the source transmits the data only when the channel gains of links are above certain threshold values. Numerical results reveal that a high spectral efficiency can be achieved by assuring a high channel gain for the link with the highest average received power among links to the destination.

The conventional TDoA (Time Difference of Arrival)-based and RSS (Received Signal Strength)-based location schemes create large positioning errors because of the various wireless channel effects such as path loss, shadowing, and NLoS (Non-Line-of-Sight) components of the multipath channels. In this paper, we propose an improved wireless location scheme which performs a weighted combination of the TDoA and RSS location schemes to improve a detection probability in the mobile-WiMAX femto-cell environments.

Introducing adaptive online data compression at network-internal nodes is considered for alleviating traffic congestion on the network. In this paper, we assume that advanced relay nodes, which possess both a relay function (network resource) and a processing function (computational and storage resources), are placed inside the network, and we propose an adaptive online lossless packet compression scheme utilized at these nodes. This scheme selectively compresses a packet according to its waiting time in the queue during congestion. Through preliminary investigation using actual traffic datasets, we investigate the compression ratio and processing time of packet-by-packet compression in actual network environments. Then, by means of computer simulations, we show that the proposed scheme reduces the packet delay time and discard rate and investigate factors necessary in achieving efficient packet relay.

A technique for reducing the footprints of HMM-based speech synthesis systems by tying all covariance matrices of state distributions is described. HMM-based speech synthesis systems usually leave smaller footprints than unit-selection synthesis systems because they store statistics rather than speech waveforms. However, further reduction is essential to put them on embedded devices, which have limited memory. In accordance with the empirical knowledge that covariance matrices have a smaller impact on the quality of synthesized speech than mean vectors, we propose a technique for clustering mean vectors while tying all covariance matrices. Subjective listening test results showed that the proposed technique can shrink the footprints of an HMM-based speech synthesis system while retaining the quality of the synthesized speech.

Limitations are found in the recent Internet because a lot of functions and protocols are patched to the original suite of layered protocols without considering global optimization. This reveals that end-to-end argument in the original Internet was neither sufficient for the current societal network and nor for a sustainable network of the future. In this position paper, we present design guidelines for a future network, which we call the New Generation Network, which provides the inclusion of diverse human requirements, reliable connection between the real-world and virtual network space, and promotion of social potentiality for human emergence. The guidelines consist of the crystal synthesis, the reality connection, and the sustainable & evolutional guidelines.

Estimating the conditional mean of an input-output relation is the goal of regression. However, regression analysis is not sufficiently informative if the conditional distribution has multi-modality, is highly asymmetric, or contains heteroscedastic noise. In such scenarios, estimating the conditional distribution itself would be more useful. In this paper, we propose a novel method of conditional density estimation that is suitable for multi-dimensional continuous variables. The basic idea of the proposed method is to express the conditional density in terms of the density ratio and the ratio is directly estimated without going through density estimation. Experiments using benchmark and robot transition datasets illustrate the usefulness of the proposed approach.

Bursty and out-of-order tuple arrivals complicate the process of determining contents and boundaries of sliding windows. To process windows over such streams efficiently, we need to address two issues regarding fast tuple insertion and disorder control. In this paper, we focus on these issues to process sliding windows efficiently over disordered data streams.

This paper investigates the autonomous decision-making process of the selection of alternative countermeasures against threats in electronic warfare settings. We introduce a threat model, which represents a specific threat pattern, and a methodology that decides the best countermeasure against real-time threats using the decision theory. To determine the optimal countermeasure, we model the probabilities of the effects of countermeasures, if executed, and combine the probabilities with their utilities. This methodology based upon the inductive threat model calculates the expected utilities of countermeasures which are applicable given a situation, and provide an intelligent command and control agent with the best countermeasure to threats. We present empirical results that demonstrate the agent's capabilities of choosing countermeasures to threats in simulated electronic warfare settings.

The rate-distortion optimization (RDO) method in the H.264/AVC encoder is an informative technology that improves the coding efficiency, but increases the computational complexity. In this letter, a fast Intra mode decision algorithm using DCT (Discrete Cosine Transform) coefficients distribution is proposed to reduce the H.264 encoder complexity. The proposed method reduces the encoder complexity on average 63.44%, while the coding efficiency is slightly decreased compared with the H.264/AVC encoder.

A time-slicing ring oscillator (TSRO) which captures time-dependent delay degradation due to periodic transient voltage drop on a power supply network is proposed. An impact of the supply voltage fluctuations, including voltage drop and overshoot, on logic circuit delay is evaluated as a change of oscillation frequency. The TSRO is designed using standard logic cells so that it can be placed almost anywhere in a digital circuit wherein supply voltage fluctuation is concerned. We also propose a new procedure for reconstructing supply voltage waveform. The procedure enables us to accurately monitor time-dependent, effective supply voltages. The -1 dB bandwidth of the TSRO is simulated to be 15.7 GHz, and measured time resolution is 131 ps. Measurement results of a test chip using 90-nm standard CMOS process successfully proved the feasibility of both delay degradation and effective supply voltage fluctuation measurements. Measurement of spatial voltage drop fluctuation is achieved.

This paper proposes a new switched-beam eight-sector antenna for multi-gigabit wireless LAN in the 60-GHz band. Our antenna system introduces access-point (AP) and user-terminal (UT) antennas having the same secθ pattern in the elevation plane so that the received signal power at the receiver is kept constant, independent of the position of the UT. For this system, an eight-sector antenna, a single-pole eight-throw (SP8T) switch, and a beam control unit are integrated as the switched-beam eight-sector antenna. The specifications of the antenna are wide bandwidth ( ≥3 GHz), high-gain ( ≥13 dBi at θ =66), and wide coverage area in both azimuth (0 ≤ φ ≤ 180) and elevation planes (0 ≤ θ ≤ 66). The antenna beam is steered within the specified response time (which is short) by the Media Access Control (MAC). In our antenna, both high gain for a wide elevation angle and wide bandwidth are obtained by using the proposed closely spaced waveguide slot array antenna, which is used as each sector of the eight-sector antenna. The SP8T switch with the beam control unit enables 180 beam scan in the azimuth plane. In a component evaluation, the eight-sector antenna achieves a 10-dB return loss bandwidth of 8 GHz with more than 40-dB port-to-port isolation. Radiation characteristics of the eight-sector antenna indicate that it covers 82% of the entire coverage area at the center frequency and that the coverage rate in the operating frequency band is from 78% to 88%. The performance of the SP8T switch and the beam control unit is verified by measuring the insertion loss at all eight ports and the switching response time. In the antenna system evaluation, measurement by using two prototype antennas as the AP and the UT antennas in the usage condition indicates that the measured received signal power meets the specified constant power for the specified wide elevation angle range, independent of the position of the UT. These experimental results verify the effectiveness of our proposed antenna for multi-gigabit WLAN.

P2P (Peer-to-Peer) file sharing architectures have scalable and cost-effective features. Hence, the application of P2P architectures to media streaming is attractive and expected to be an alternative to the current video streaming using IP multicast or content delivery systems because the current systems require expensive network infrastructures and large scale centralized cache storage systems. In this paper, we investigate the P2P progressive download enabling Internet video streaming services. We demonstrated the capability of the P2P progressive download in both laboratory test network as well as in the Internet. Through the experiments, we clarified the contribution of the FTTH links to the P2P progressive download in the heterogeneous access networks consisting of FTTH and ADSL links. We analyzed the cause of some download performance degradation occurred in the experiment and discussed about the effective methods to provide the video streaming service using P2P progressive download in the current heterogeneous networks.

This paper considers the use of an antenna selection mechanism to reduce the cost of multiple analog transmit/receive chains in multiple-input multiple-output (MIMO) systems. With the optimal antenna selection scheme, radio-frequency chains can optimally connect with the best subset of transmitter and/or receiver antennas. However, the optimal antenna selection algorithm requires an exhaustive search of all possible combinations to find the optimum subset at the transmitter and/or receiver, thus resulting in high complexity. In order to reduce the computational load while still maximizing channel capacity, we introduce the simulated annealing (SA) method, an effective algorithm that solves various combinatorial optimization problems, to search the optimal subset. The simulation results show that the performance of the proposed SA method provides almost the same channel capacity as that of the optimal exhaustive search algorithm while maintaining low complexity.