3900881
HxH: a hop-by-hop transport protocol for multi-hop wireless networks
TCP can perform poorly in multi-hop wireless networks due to problems that arise with contention and mobility. Endto-end protocols are at an inherent disadvantage in trying to solve these problems because their feedback loop operates over multiple wireless hops, which makes it difficult to diagnose problems that occur several hops away and hinders their ability to adapt to changing network conditions. In this paper, we design HxH, a hop-by-hop transport protocol that uses credit-based congestion control and reverse ACKs to solve many of the problems observed with TCP. We use a simulation study to demonstrate that our hop-by-hop approach allows HxH to respond quickly to changing network conditions and to exploit the unique characteristics of wireless networks to reduce overhead. We show that HxH greatly increases throughput and improves fairness, as compared to several end-to-end protocols, in both mesh and mobile ad hoc networks.
8065609
Link quality prediction for wireless devices with multiple radios
Communication between wireless devices ought to be as simple as possible; they should be able to seamlessly switch between different radios and network stacks on the fly in order to better serve the user. To make this a possibility, we consider the challenging problem of predicting link quality in a changing mobile environment. In this paper we present an algorithm that uses Weighted Least Squares Regression to predict whether a given link can meet application requirements in terms of throughput, delay, and jitter. We use a simulation study to demonstrate that our algorithm is able to predict link quality accurately and stably in a frequently changing mobile environment. The prediction algorithm is more accurate than several alternative algorithms, and the overhead caused by the link measurements is negligible in terms of throughput and power consumption.
11915654
Hybrid Neural Network Architecture for On-Line Learning
Approaches to machine intelligence based on brain models use neural networks for generalization but they do so as signal processing black boxes. In reality, the brain consists of many modules that operate in parallel at different levels. In this paper we propose a more realistic biologically inspired hybrid neural network architecture that uses two kinds of neural networks simultaneously to consider short-term and long-term characteristics of the signal. The first of these networks quickly adapts to new modes of operation whereas the second one provides more accurate learning within a specific mode. We call these networks the surfacing and deep learning agents and show that this hybrid architecture performs complementary functions that improve the overall learning. The performance of the hybrid architecture has been compared with that of back-propagation perceptrons and the CC and FC networks for chaotic time-series prediction, the CATS benchmark test, and smooth function approximation. It is shown that the proposed architecture provides a superior performance based on the RMS error criterion.
16394212
A pharmacogenomic study on the polymorphic gene response to risperidone in schizophrenia patients
Risperidone is a widely used atypical antipsychotic medication, which has currently raised considerable interest in individual differences in patient response to it. Although risperidone is one of the major atypical anti-psychotics, there is a lack of pharmacogenetic studies on it, especially in Asian populations. This paper investigates the relationship between the -1438 A/G polymorphism of 5-HT2A and response to risperidone treatment. In this study, 130 schizophrenia patients were recruited, who were treated with risperidone monotherapy for eight weeks. Clinical response was assessed on the positive and negative syndrome scale (PANSS) on the day of admission and was subsequently assessed after eight weeks following the treatment. The -1438 A/G polymorphism was identified by direct sequencing. The confounding effects of nongenetic factors were estimated and the baseline symptom score was included as a covariate for adjustment. Association tests between genotype and percentage improvement in total PANSS scores, as well as positive symptom scores and negative symptom scores, were performed using analysis of variance (ANOVA). We find no significant differences in response to the treatment in terms of PANSS or subscore improvements among the subgroups according to different genotypes. Further studies on larger groups are planned to confirm the result.
6804902
An audio wiki supporting mobile collaboration
Wikis have proved to be very effective collaboration and knowledge management tools in large variety of fields thanks to their simplicity and flexible nature. Another important development for the internet is the emergence of powerful mobile devices supported by fast and reliable wireless networks. The combination of these developments begs the question of how to extend wikis on mobile devices and how to leverage mobile devices' rich modalities to supplement current wikis. Realizing that composing and consuming through auditory channel is the most natural and efficient way for mobile device user, this paper explores the use of audio as the medium of wiki. Our work, as the first step towards this direction, creates a framework called Mobile Audio Wiki which facilitates asynchronous audio-mediated collaboration on the move. In this paper, we present the design of Mobile Audio Wiki. As a part of such design, we propose an innovative approach for a light-weight audio content annotation system for enabling group editing, versioning and cross-linking among audio clips. To elucidate the novel collaboration model introduced by Mobile Audio Wiki, its four usage modes are identified and presented in storyboard format. Finally, we describe the initial design for presentation and navigation of Mobile Audio Wiki.
16539998
Lossy to lossless image compression based on reversible integer DCT
A progressive image compression scheme is investigated using reversible integer discrete cosine transform (RDCT) which is derived from the matrix factorization theory. Previous techniques based on DCT suffer from bad performance in lossy image compression compared with wavelet image codec. And lossless compression methods such as IntDCT, I2I-DCT and so on could not compare with JPEG-LS or integer discrete wavelet transform (DWT) based codec. In this paper, lossy to lossless image compression can be implemented by our proposed scheme which consists of RDCT, coefficients reorganization, bit plane encoding, and reversible integer pre- and post-filters. Simulation results show that our method is competitive against JPEG-LS and JPEG2000 in lossless compression. Moreover, our method outperforms JPEG2000 (reversible 5/3 filter) for lossy compression, and the performance is even comparable with JPEG2000 which adopted irreversible 9/7 floating-point filter (9/7F filter).
13235702
Provisioning QoS guarantee by multipath routing and reservation in Ad hoc networks
In this paper, a QoS multipath source routing protocol (QoS-MSR) is proposed for ad hoc networks. It can collect QoS information through route discovery mechanism of multipath source routing (MSR) and establish QoS route with reserved bandwidth. In order to reserve bandwidth efficiently, a bandwidth reservation approach called the multipath bandwidth splitting reservation (MBSR) is presented, under which the overall bandwidth request is split into several smaller bandwidth requests among multiple paths. In simulations, the anthors introduce Insignia, an in-bind signaling system that supports QoS in ad hoc networks, and extend it to multipath Insignia (M-Insignia) with QoS-MSR and MBSR. The results show that QoS-MSR routing protocol with the MBSR algorithm can improve the call admission ratio of QoS traffic, the packet delivery ratio, and the end-to-end delay of both best-effort traffic and QoS traffic. Therefore, QoS-MSR with MBSR is an efficient mechanism that supports QoS for ad hoc networks.