An ad-hoc network is the cooperative engagement of a collection of mobile nodes without the required intervention of any centralized access point or existing infrastructure. We present Ad-hoc On Demand Distance Vector Routing (AODV), a novel algorithm for the operation of such ad-hoc networks. Each mobile host operates as a specialized router, and routes are obtained as needed (i.e., on-demand) with little or no reliance on periodic advertisements. Our new routing algorithm is quite suitable for a dynamic self starting network, as required by users wishing to utilize ad-hoc networks. AODV provides loop-free routes even while repairing broken links. Because the protocol does not require global periodic routing advertisements, the demand on the overall bandwidth available to the mobile nodes is substantially less than in those protocols that do necessitate such advertisements. Nevertheless we can still maintain most of the advantages of basic distance vector routing mechanisms. We show that our algorithm scales to large populations of mobile nodes wishing to form ad-hoc networks. We also include an evaluation methodology and simulation results to verify the operation of our algorithm.

/pdf/ad-hoc-on-demand-distance-vector-routing-3w61wv0p1h.pdf

Ad-hoc on-demand distance vector routing

人教版高中英语新课程教材中,语言运用（Using Language）是每个单元必不可少的部分,提供了围绕单元中心话题的听、说、读、写的综合性练习,是单元中心话题的延续和升华.如何设计Using Language部分的教学,使自己的教学模式既不落俗套,又能真正体现新课程标准所倡导的教学理念,正是广大一线英语教师一直努力探索的问题.

打磨Using Language,倡导新理念

This paper describes a self-organizing, multihop, mobile radio network which relies on a code-division access scheme for multimedia support. In the proposed network architecture, nodes are organized into nonoverlapping clusters. The clusters are independently controlled, and are dynamically reconfigured as the nodes move. This network architecture has three main advantages. First, it provides spatial reuse of the bandwidth due to node clustering. Second, bandwidth can be shared or reserved in a controlled fashion in each cluster. Finally, the cluster algorithm is robust in the face of topological changes caused by node motion, node failure, and node insertion/removal. Simulation shows that this architecture provides an efficient, stable infrastructure for the integration of different types of traffic in a dynamic radio network.

Adaptive clustering for mobile wireless networks

Digital processing of speech signals

The present invention is generally directed to a system for monitoring a variety of environmental and/or other conditions within a defined remotely located region. In one aspect, a system is configured to monitor utility meters (613) in a defined area. The system is implemented by using a plurality of wireless transmitters (614), each integrated into a sensor (612) adapted to monitor a particular data input. The system also includes a plurality of transceivers (221) that are dispersed throughout the region at defined locations. The system uses a local gateway (210) to translate and transfer information from the transmitters to a dedicated computer (260) on a network (230). The dedicated computer collects, compiles and stores the data for retrieval upon client demand across the network. The computer further includes means for evaluating the received information and identifying an appropriate control signal to be applied at a designated actuator.

System and method for monitoring and controlling remote devices

This paper focuses on the problem of pitch tracking in noisy conditions. A method using harmonic information in the residual signal is presented. The proposed criterion is used both for pitch estimation, as well as for determining the voicing segments of speech. In the experiments, the method is compared to six state-of-the-art pitch trackers on the Keele and CSTR databases. The proposed technique is shown to be particularly robust to additive noise, leading to a significant improvement in adverse conditions. Index Terms: fundamental frequency, pitch tracking, pitch estimation, voicing decisions

/pdf/joint-robust-voicing-detection-and-pitch-estimation-based-on-1e5qeti3cg.pdf

Joint Robust Voicing Detection and Pitch Estimation Based on Residual Harmonics

Magnetic resonance images of the vocal tract during the sustained phonation of /l/ (both dark and light allophones) by four native American English talkers are employed for measuring lengths, area functions, and cavity volumes and for the analysis of 3-D vocal tract and tongue shapes Electropalatography contact profiles are used for studying inter- and intra-talker variabilities and as a source of converging evidence for the magnetic resonance imaging study The general 3-D tongue body shapes for both allophones of /l/ are characterized by a linguo-alveolar contact together with inward lateral compression and convex cross sections of the posterior tongue body region The lateral compression along the midsagittal plane enables the creation of flow channels along the sides of the tongue The bilateral flow channels exhibit somewhat different areas, a characteristic which is talker-dependent Dark /l/s show smaller pharyngeal areas than the light varieties due to tongue-root retraction and/or posterior tongue body raising The acoustic implications of the observed geometries are discussed

/pdf/toward-articulatory-acoustic-models-for-liquid-approximants-4jnlyho1c9.pdf

Toward articulatory-acoustic models for liquid approximants based on MRI and EPG data. Part I. The laterals

Magnetic resonance images of the vocal tract during sustained production of the fricatives /s, sh, f, θ, z, yog, v, edh/ by four subjects are analyzed. Measurements of vocal‐tract lengths and area functions, and morphological analyses of the vocal tract and tongue shapes for these sounds are presented. Interspeaker differences in area functions are found to be greater in the pharyngeal cavity than in the buccal cavity with the nonstrident fricatives exhibiting greater differences than the strident ones. The anterior tongue body of the alveolar stridents exhibit concave cross‐sectional shapes while that of the postalveolars show a relatively raised tongue body with flat or slightly convex cross‐sectional shapes. The concave tongue shapes of the alveolars result in a more abrupt area function behind the constriction when compared to that of the postalveolars. Laminality or apicality of articulation is found to be speaker dependent. Moreover, a greater degree of anterior medial grooving and lateral lingua‐pa...

An articulatory study of fricative consonants using magnetic resonance imaging

The authors consider a networking environment in which the users are mobile, the topology changes, code division multiple access (CDMA) provides multiple wireless channels, the bandwidth of a given link is unpredictable and possibly very low, the error rates are extremely high and variable, major interference occurs when multiple transmissions take place over (possibly different) links on the same or different codes, real-time multimedia traffic must be supported as well as datagram traffic, there is no stable communication infrastructure, and there is no central control. They consider the problem of developing a design prototyping methodology, performance evaluation techniques, and networking algorithms to support a rapidly deployable radio network for such an environment. The network must be capable of providing guaranteed quality of service (QoS) to real-time multimedia traffic in a mobile, wireless, multihop radio network with no fixed infrastructure (e.g., no base stations). Another element of the environment with which they deal is that of multihop communications. They focus on two layers of key importance in multimedia wireless network design, namely compression algorithms and adaptivity in the voice/video applications layer, and network algorithms at the wireless subnet layer. Simulation tools are used to evaluate our design as well as to provide a path toward their implementation in software.

adaptive mobile multimedia networks

The effects of age, sex, and vocal tract configuration on the glottal excitation signal in speech are only partially understood, yet understanding these effects is important for both recognition and synthesis of speech as well as for medical purposes. In this paper, three acoustic measures related to the voice source are analyzed for five vowels from 3145 CVC utterances spoken by 335 talkers (8-39 years old) from the CID database [Miller et al., Proceedings of ICASSP, 1996, Vol. 2, pp. 849-852]. The measures are: the fundamental frequency (F0), the difference between the "corrected" (denoted by an asterisk) first two spectral harmonic magnitudes, H1* - H2* (related to the open quotient), and the difference between the "corrected" magnitudes of the first spectral harmonic and that of the third formant peak, H1* - A3* (related to source spectral tilt). The correction refers to compensating for the influence of formant frequencies on spectral magnitude estimation. Experimental results show that the three acoustic measures are dependent to varying degrees on age and vowel. Age dependencies are more prominent for male talkers, while vowel dependencies are more prominent for female talkers suggesting a greater vocal tract-source interaction. All talkers show a dependency of F0 on sex and on F3, and of H1* - A3* on vowel type. For low-pitched talkers (F0 < or = 175 Hz), H1* - H2* is positively correlated with F0 while for high-pitched talkers, H1* - H2* is dependent on F1 or vowel height. For high-pitched talkers there were no significant sex dependencies of H1* - H2* and H1* - A3*. The statistical significance of these results is shown.

/pdf/age-sex-and-vowel-dependencies-of-acoustic-measures-related-1wg9yhqwru.pdf

Abeer Alwan

Papers

Joint Robust Voicing Detection and Pitch Estimation Based on Residual Harmonics

Toward articulatory-acoustic models for liquid approximants based on MRI and EPG data. Part I. The laterals

An articulatory study of fricative consonants using magnetic resonance imaging

adaptive mobile multimedia networks

Age, sex, and vowel dependencies of acoustic measures related to the voice source.