759 research outputs found

    TCP-Swift: An end-host enhancement scheme for TCP over satellite IP networks

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    A new transport layer protocol called TCP-Swift is proposed for enhancing the TCP performance over satellite IP networks. TCP-Swift replaces the conventional TCP slow start and fast recovery algorithms by speedy start and speedy recovery. With speedy start, a TCP-Swift sender opens up its congestion window in only two round trip times. This significantly shortens the time needed in probing the network for equilibrium state. With speedy recovery, we can infer the cause of a packet loss by observing the ACK stream received at the sender. If the loss is due to wireless transmission error, the sender's congestion window can be re-opened up more aggressively to fully utilize the available satellite link bandwidth. We show that TCP-Swift outperforms existing TCP schemes by simulations.published_or_final_versio

    G-Snoop: Enhancing TCP performance over wireless networks

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    Focusing on a general wireless network where a wireless link can be at any link along the sender-to-receiver path, a new TCP enhancement scheme, called Generalized-Snoop (G-Snoop), is proposed. Since many existing applications are built on top of TCP, it is essential that any TCP enhancement scheme should be transparent to the end-systems as well as the fixed networks. To achieve this, G-Snoop only needs to be implemented at the wireless gateways, no other parts of the network require modifications. With G-Snoop, TCP senders are shielded from non-congestion packet loss and thus no unnecessary congestion control mechanisms will be performed. Simulation results show that significant throughout gain can be obtained with G-Snoop.published_or_final_versio

    Recognition of speech commands using a modified neural fuzzy network and an improved GA

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    Author name used in this publication: K. F. LeungAuthor name used in this publication: F. H. F. LeungAuthor name used in this publication: P. K. S. TamCentre for Multimedia Signal Processing, Department of Electronic and Information EngineeringRefereed conference paper2002-2003 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

    Application of a modified neural fuzzy network and an improved genetic algorithm to speech recognition

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    This paper presents the recognition of speech commands using a modified neural fuzzy network (NFN). By introducing associative memory (the tuner NFN) into the classification process (the classifier NFN), the network parameters could be made adaptive to changing input data. Then, the search space of the classification network could be enlarged by a single network. To train the parameters of the modified NFN, an improved genetic algorithm is proposed. As an application example, the proposed speech recognition approach is implemented in an eBook experimentally to illustrate the design and its merits. © Springer-Verlag London Limited 2007

    On interpretation of graffiti digits and characters for eBooks : neural-fuzzy network and genetic algorithm approach

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    Author name used in this publication: K. F. LeungCentre for Multimedia Signal Processing, Department of Electronic and Information Engineering2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Neural fuzzy network and genetic algorithm approach for Cantonese speech command recognition

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    Author name used in this publication: K. F. LeungAuthor name used in this publication: F. H. F. LeungAuthor name used in this publication: P. K. S. TamCentre for Multimedia Signal Processing, Department of Electronic and Information EngineeringRefereed conference paper2002-2003 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

    On interpretation of Graffiti digits and characters for eBooks: Neural-fuzzy network and genetic algorithm approach

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    This paper presents the rule optimization, tuning of the membership functions, and optimization of the number of fuzzy rules, of a neural-fuzzy network (NFN) using a genetic algorithm (GA). The objectives are achieved by training a proposed NFN with rule switches. The proposed NFN and GA are employed to interpret graffiti number inputs and commands for electronic books (eBooks)

    Electroacupuncture provides a new approach to neuroprotection in rats with induced glaucoma

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    Objectives: To investigate, using multifocal electroretinogram (mfERG), the effect of electroacupuncture (EA) on retinal function in rats with experimental glaucoma. Design and subjects: Glaucoma was induced in the right eyes of 15 adult female Sprague-Dawley rats by laser photocoagulation for three quarters of the perilimbal and episcleral vessels. The left eye of each rat was used as the control. The animals were divided into 3 groups: no treatment (non-EA control group), 2 Hz EA group, and 100 Hz EA group. EA treatment at different frequencies can produce different levels of analgesia and hence the effect of EA with different frequencies on glaucoma treatment was investigated. Both eyes of each rat in the EA experimental groups received 3 EA treatment sessions each week for 4 weeks. The retinal function was measured using mfERG after 4 weeks of EA treatment. Results: There was no significant difference in the amplitude (both N1 trough and P1 peak) of mfERG first- order kernel response between the treatment and control groups. In determining the waveform characteristics by the ratio of N1 amplitude to P1 amplitude (N/P ratio), obvious differences were found in the N/P ratio between the control eyes and the glaucoma eyes in the non-EA group and the 100 Hz EA treatment group, but similar values in the N/P ratio were observed between the control eyes and the glaucoma eyes in the 2 Hz EA treatment group. The waveform from the eyes with glaucoma was deformed in both the non-EA group and the 100 Hz EA group, but the waveform from the glaucomatous eye was preserved in the 2 Hz EA group. Conclusions: Application of EA at 2 Hz provides neuroprotection by preserving retinal function in rats with experimental glaucoma. Low frequency EA may be an alternative therapy in the treatment of glaucoma. © Mary Ann Liebert, Inc.published_or_final_versio

    A Hybrid Microwave-Optical Applicator for Local Muscle Warming and Monitoring

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    Local warming of human tissue causes vasodilation and therefore blood volume to increase. Such thermal blood volume response allows the assessment of microcirculation in tissue, providing clinically important information. The deep warming is provided by a novel microwave applicator, which has a annular-ring microstrip patch operating at 2450 MHz with a superstrate interface layer to improve the coupling of electromagnetic (EM) waves into the skin. The design is based on computer simulations of specific absorption rate (SAR) and thermal distribution of the EM waves in a biological medium. The simulation results show that the applicator can elevate the muscle temperature by 3 to 4^{\circ}\mathrm{C}. The thermal response is measured by an integrated optical probe which measures tissue oxygenation changes in deep tissue using the near infrared spectroscopy technique

    A novel push-and-pull hybrid data broadcast scheme for wireless information networks

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    A new push-and-pull hybrid data broadcast scheme is proposed for providing wireless information services to three types of clients, general, pull and priority clients. Only pull and priority clients have the back channel for sending requests to the broadcast server. There is no scalability problem with the hybrid scheme because the amount of pull and priority clients is very small. Based on the requests collected from pull and priority clients, the server estimates the interest pattern changes of the whole client population. Then the broadcast schedule on the push channel for the next broadcast cycle is adjusted. Besides the push channel, a small amount of broadcast bandwidth is allocated to a pull channel. The data to be broadcast on the pull channel is decided by the server in real-time and priority is given to requests from priority clients. Simulations show that with a time-varying client interest pattern, the average data access time for all three types of clients can be minimized. Because of the priority in using the pull channel, priority clients can achieve the lowest access time and pull clients can achieve a lower access time than general clients. To further improve the performance, the hybrid scheme with local client cache is also investigated.published_or_final_versio
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