This paper describes a novel method to improve the performance of second language speech recognition when the mother tongue of users is known. Considering that second language speech usually includes less fluent pronunciation and more frequent pronunciation mistakes, the authors propose using a reduced phoneme set generated by a phonetic decision tree (PDT)-based top-down sequential splitting method instead of the canonical one of the second language. The authors verify the efficacy of the proposed method using second language speech collected with a translation game type dialogue-based English CALL system. Experiments show that a speech recognizer achieved higher recognition accuracy with the reduced phoneme set than with the canonical phoneme set.

The potential of infrastructureless vehicular ad hoc networks (VANETs) for providing multihop applications is quite significant. Although the Epidemic Routing protocol performs well in highly mobile and frequently disconnected VANETs with low vehicle densities or light packet traffic loads, its performance degrades greatly in environments of high vehicle density together with heavy packet traffic loads that create serious bandwidth contention and frequent collisions. We propose a new epidemic routing protocol in urban environments called Greedy Zone Epidemic Routing (GZER), in which the neighbors of a vehicle are divided into different zones according to their physical locations. Each vehicle maintains a summary vector (SV) of packets buffered locally and zone summary vectors (ZSVs) of all packets buffered in each zone. Whether the infection will be transmitted in each zone is decided by the difference between SV and ZSV. Simulation results show that the proposed GZER protocol outperforms the existing solutions significantly, especially in the environments of high vehicle densities together with heavy packet traffic loads.

In this paper, we address the issue of interference alignment (IA) in a two-cell network and consider both inter-cell and intra-cell interferences. For cell one, a linear processing scheme is proposed to align the inter-cell interference to the same signal dimension space of intra-cell interference. For cell two, we propose a distributed interference alignment scheme to manage the interference from the nearby cell. We assume that the relay works in an amplify-and-forward (AF) mode with a half-duplex and MIMO relaying. We show that the composite desired and interfering signals aggregated over two time slots can be aligned such that the interfering signal is eliminated completely by applying a linear filter at the receiver. The precoding matrix of the relay is optimized jointly with the precoding matrix of the base station (BS). The number of data streams is optimized jointly for every user terminal (UT). The degree of freedom (DoF) performance of the proposed scheme as well as the conventional cooperation scheme are derived for multiple antennas at both base stations, relay station and user terminals. Simulation results show that the proposed alignment scheme can achieve a better DoF performance.

The Boolean network can be used as a mathematical model for gene regulatory networks. An attractor, which is a state of a Boolean network repeating itself periodically, can represent a stable stage of a gene regulatory network. It is known that the problem of finding an attractor of the shortest period is NP-hard. In this article, we give a fixed-parameter algorithm for detecting a singleton attractor (SA) for a Boolean network that has only AND and OR Boolean functions of literals and has bounded treewidth k. The algorithm is further extended to detect an SA for a constant-depth nested canalyzing Boolean network with bounded treewidth. We also prove the fixed-parameter intractability of the detection of an SA for a general Boolean network with bounded treewidth.

In this paper, we propose a new cross-layer scheme Cooperation between channel Access control and TCP Rate Adaptation (CATRA) aiming to manage TCP flow contention in multi-hop ad hoc networks. CATRA scheme collects useful information from MAC and physical layers to estimate channel utilization of the station. Based on this information, we adjust Contention Window (CW) size to control the contention between stations. It can also achieve fair channel access for fair channel access of each station and the efficient spatial channel usage. Moreover, the fair value of bandwidth allocation for each flow is calculated and sent to the Transport layer. Then, we adjust the sending rate of TCP flow to solve the contention between flows and the throughput of each flow becomes fairer. The performance of CATRA is examined on various multi-hop network topologies by using Network Simulator (NS-2).

This paper proposes a speech watermarking method based on the concept of formant tuning. The characteristic that formant tuning can improve the sound quality of synthesized speech was employed to achieve inaudibility for watermarking. In the proposed method, formants were firstly extracted with linear prediction (LP) analysis and then embedded with watermarks by symmetrically controlling a pair of line spectral frequencies (LSFs) as formant tuning. We evaluated the proposed method by two kinds of experiments regarding inaudibility and robustness compared with other methods. Inaudibility was evaluated with objective and subjective tests and robustness was evaluated with speech codecs and speech processing. The results revealed that the proposed method could satisfy both inaudibility and robustness that required for speech watermarking.

The spatial relations between sensors placed for target detection can be inferred from the responses of individual sensors to the target objects. Motivated by this fact, this paper proposes a method for estimating the location of sensors by using their responses to target objects. The key idea of the proposal is that when two or more sensors simultaneously detect an object, the distances between these sensors are assumed to be equal to a constant called the basic range. Thus, new pieces of proximity information are obtained whenever an object passes over the area in which the sensors are deployed. This information is then be aggregated and transformed into a two dimensional map of sensors by solving a nonlinear optimization problem, where the value of the basic range is estimated together. Simulation experiments verify that the proposed algorithm yields accurate estimates of the locations of sensors.

In this paper, generic attacks are presented against hash functions that are constructed by a hashing mode instantiating a Feistel or generalized Feistel networks with an SP-round function. It is observed that the omission of the network twist in the last round can be a weakness against preimage attacks. The first target is a standard Feistel network with an SP round function. Up to 11 rounds can be attacked in generic if a condition on a key schedule function is satisfied. The second target is a 4-branch type-2 generalized Feistel network with an SP round function. Up to 15 rounds can be attacked in generic. These generic attacks are then applied to hashing modes of ISO standard ciphers Camellia-128 without FL and whitening layers and CLEFIA-128.

In this paper, we present a new mathematical framework based on point process theory for a type of four-way handshake-based medium access control schemes which have so far only been studied by simulation. The theoretical model we present takes into account time-varying channel impairments, the interference inherent to large networks, different decoding requirements for each packet and the influence of the routing protocol. Moreover, in contrast with the majority of the literature, the influence of imperfect feedback is also considered in the analysis. Throughout the paper, we derive in closed forms the average link outage probability as well as the Average Spatial Density of Transport (ASDT) in a mobile multi-hop ad hoc network. All results are confirmed by comparison to simulated data and lead to two general conclusions. In the presence of fading uncorrelated between traffic and control handshakes, we observe the following. 1) Optimal contention is achieved by designing control packets that are decodable even in the presence of strong interference. 2) The impact of imperfect feedback on performance in an interference-limited mobile ad hoc network is not negligible.

This paper proposes a method to reduce the playback suspension in a Video-on-Demand system based on the Peer-to-Peer technology (P2P VoD). Our main contribution is twofold. The first is the proposal of a hierarchical P2P architecture with the notion of dynamic swarms. Swarm is a group of peers to have similar playback position and those swarms are connected with an overlay so that requested pieces are forwarded from a swarm to another swarm in a bucket brigade manner, where the forward of pieces is regulated by the super-peer (SP) of each swarm. The second contribution is the proposal of a match making scheme between requests and uploaders. The simulation result indicates that the proposed scheme reduces the total waiting time of a randomized scheme by 24% and the load of the media server by 76%.

This research deals with muffled speech as the evaluation target and introduces a criterion for evaluating the auditory impression in muffled speech. It focuses on the vocal tract area function (VTAF) to evaluate the auditory impression, and the criterion uses temporal differentiation of this function to track the temporal variation of the shape of the mouth. The experimental results indicate that the proposed criterion can be used to evaluate the auditory impression as well as the subjective impression.

The joint power allocation (PA) issue is studied in multi-user three-cell systems under the degree-of-freedom (DoF) based transmission protocol. This protocol makes all the interferences received at each user orthogonal to the useful signal at the same user by Jafar's topological interference management through index coding, which is proved to offer full DoF. Under this protocol, we formulate the joint power allocations problem based on the objective of energy efficiency under the required quality-of-service constraint. Due to the highly complicated Lagrangian equation, the properties of Lambert function are widely exploited to solve the problem using a closed-form expression. It is discovered that the relationship among the optimal power coefficients are completely different from that of the well-known water-filling method. Simulations demonstrate the energy efficiency of the designed scheme.

The reliability of electromagnetic relay (EMR) which contains a permanent magnet (PM) can be improved by a robust design method. In this parameter design process, the calculation of electromagnetic system is very important. In analytical calculation, PM is often equivalent to a lumped parameter model of one magnetic resistance and one magnetic potential, but significant error is often caused; in order to increase the accuracy, a distributed parameter calculation model (DPM) of PM bar is established; solution procedure as well as verification condition of this model is given; by a case study of the single PM bar, magnetic field lines division method is adopted to build the DPM, the starting point and section magnetic flux of each segment are solved, a comparison is made with finite element method (FEM) and measured data; the accuracy of this magnetic field line based distributed parameter model (MFDPM) in PM bar is verified; this model is applied to the electromagnetic system of a certain type EMR, electromagnetic system calculation model is established based on MFDPM, and the static force is calculated under different rotation angles; compared with traditional lumped parameter model and FEM, it proves to be of acceptable calculation accuracy and high calculation speed which fit the requirement of robust design.

This paper proposes a consistency maintenance scheme for P2P file sharing systems. The basic idea of the proposed scheme is to construct a static tree for each shared file to efficiently propagate the update information to all replica peers. The link to the root of the trees is acquired by referring to a Chord ring which stores the mapping from the set of shared files to the set of tree roots. The performance of the scheme is evaluated by simulation. The simulation result indicates that: 1) it reduces the number of messages in the Li's scheme by 54%, 2) it reduces the propagation delay of the scheme by more than 10%, and 3) the increase of the delay due to peer churns is effectively bounded provided that the percentage of leaving peers is less than 40%.

With the shorter time-to-market and the rising cost in SoC development, the demand for post-silicon programmability has been increasing. Recently, programmable accelerators have attracted more attention as an enabling solution for post-silicon engineering change. However, programmable accelerators suffers from 5∼10X less energy efficiency than fixed-function accelerators mainly due to their extensive use of memories. This paper proposes a highly energy-efficient accelerator which enables post-silicon engineering change by a control patching mechanism. Then, we propose a patch compilation method from a given pair of an original design and a modified design. We also propose a design method to add redundant wires in advance to decrease the necessary amount of patch memory for post-silicon engineering change. Experimental results demonstrate that the proposed accelerators offer high energy efficiency competitive to fixed-function accelerators and can achieve about 5X higher efficiency than the existing programmable accelerators. We also show the trade-off between redundant wires and the necessary amount of patch memory.

This paper proposes to obtain high-level, domain-robust representations for cross-view face recognition. Specially, we introduce Convolutional Deep Belief Networks (CDBN) as the feature learning model, and an CDBN based interpolating path between the source and target views is built to model the correlation of cross-view data. The promising results outperform other state-of-the-art methods.

In this paper, with a modification of our earlier construction in [12], new classes of optimal LHZ FHS sets with new parameters are obtained which are optimal in the sense that their parameters meet the Peng-Fan-Lee bound. It is shown that all the sequences in the proposed FHS sets are shift distinct. The proposed FHS sets are suitable for quasi-synchronous time/frequency hopping code division multiple access systems to eliminate multiple-access interference.

A two-dimensional (2D) wireless power transmission (WPT) system that handles a wide range of transmitted and received power is proposed and evaluated. A transmitter outputs the power to an arbitrary position on a 2D waveguide sheet by using a beam-forming technique. The 2D waveguide sheet does not require an absorber on its edge. The minimum propagation power on the sheet is increased 18 times by using the beam-forming technique. Power amplifier (PA) efficiency was improved from 19% to 46% when the output power was 10dB smaller than peak power due to the use of a PA supply-voltage and input power control method. Peak PA efficiency was 60%. A receiver inputs a wide range of power levels and drives various load impedances with a parallel rectifier. This rectifier enables a number of rectifying units to be tuned dynamically. The rectifier efficiency was improved 1.5 times while input power range was expanded by 6dB and the load-impedance range was expanded fourfold. The rectifier efficiency was 66-73% over an input power range of 18-36dBm at load impedances of 100 and 400Ω.

This paper presents an adaptive feedback canceller (AFC) based on a pseudo affine projection (PAP) algorithm that can provide fast and stable adaptation to the time-varying environment. The proposed algorithm utilizes the adaptive linear prediction (LP) to obtain the LP coefficients of input signal model and the inverse gain filter (IGF) to alleviate the effect of compensation gain. As a result, when the input is model as an AR signal, the proposed algorithm satisfies the condition for having an almost unbiased estimatie of the feedback path and then its performance is relatively independent of the gain setting of hearing aids. Simulation results showed that the proposed algorithm is capable of obtaining unbaised feedback path estimates and high speech quality.

To achieve more high speed and high quality systems of wireless communications, orthogonal frequency division multiple access (OFDMA) has been proposed. Moreover, OFDMA considering the multiuser diversity (MUDiv) has been also proposed to achieve more high system performance. On the other hand, the conventional MUDiv/OFDMA requires large complexity to select the subcarrier of each user. To solve this problem, we have proposed a MUDiv/OFDMA based on the low granularity block (LGB). However, it degrades the system performance in the environment which contains many deep faded subcarrier channels. Therefore, in this paper, we propose a cooperative LGB-MUDiv/OFDMA to mitigate the influence due to the deep faded subcarrier channel.