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IEEE Global Communications Conference

作者： Shicong Yang Michael Krishnan Avideh Zakhor Department of Electrical Engineering and Computer Sciences University of California

ISBN: (纸本)9781479959532

Access Point (AP) selection is important in WLANs as it affects the throughput of the joining station (STA). In this paper, we propose a class of AP selection algorithms to maximize the joining STA's expected throughput by considering interference at STAs, and transmit opportunities (TXOPs) at APs. Specifically, we collect a binary-valued local channel occupancy signal, called busy-idle (BI) signal, at each node and require the APs to periodically broadcast their BI signal and a quantity representing their TXOPs. This enables the joining STA to estimate throughput from candidate APs before selecting one. We use NS-2 simulations to demonstrate the effectiveness of our algorithms for saturated UDP and TCP downlink traffic, and compare them with received signal power (rxpwr) algorithm, load based algorithm, and Fukuda algorithm. For a random topology consisting of 24 APs and 60 STAs, our algorithms increase the joining STAs average throughput by as much as 42% and 24% compared to rxpwr for UDP and TCP respectively. The achieved average throughput is 90% and 93% of that obtained via the optimal selection. We also show that, in contrast to rxpwr, the throughput of proposed algorithms remains close to optimal with the increase in AP or STA density.

关键词： Throughput wireless local area network (WLAN) access points xylometazoline Apus user datagram protocol/internet protocol Uridine Diphosphate AP algorithms stormwater treatment areas optimal selection

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Towards the synthesis of glycosylated dihydrochalcone natural products using glycosyltransferase-catalysed cascade reactions

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GREEN CHEMISTRY 2014年第9期16卷 4417-4425页

作者： Gutmann, Alexander Bungaruang, Linda Weber, Hansjoerg Leypold, Mario Breinbauer, Rolf Nidetzky, Bernd Graz Univ Technol NAWI Graz Inst Biotechnol & Biochem Engn A-8010 Graz Austria Graz Univ Technol NAWI Graz Inst Organ Chem A-8010 Graz Austria Austrian Ctr Ind Biotechnol A-8010 Graz Austria

Regioselective O-beta-D-glucosylation of flavonoid core structures is used in plants to create diverse natural products. Their prospective application as functional food and pharmaceutical ingredients makes flavonoid glucosides interesting targets for chemical synthesis, but selective instalment of a glucosyl group requires elaborate synthetic procedures. We report glycosyltransferase-catalysed cascade reactions for single-step highly efficient O-beta-D-glucosylation of two major dihydrochalcones (phloretin, davidigenin) and demonstrate their use for the preparation of phiorizin (phloretin 2'-O-beta-D-glucoside) and two first-time synthesised natural products, davidioside and confusoside, obtained through selective 2'- and 4'-O-beta-D-glucosylation of the dihydroxyphenyl moiety in davidigenin, respectively. Parallel biocatalytic cascades were established by coupling uridine 5'-diphosphate (UDP)-glucose dependent synthetic glucosylations catalysed by herein identified dedicated O-glycosyltransferases (OGTs) to UDP dependent conversion of sucrose by sucrose synthase (SuSy;from soybean). The SuSy reaction served not only to regenerate the UDP-glucose donor substrate for OGT (up to 9 times), but also to overcome thermodynamic restrictions on dihydrochalcone beta-D-glucoside formation (up to 20% conversion and yield enhancement). Using conditions optimised for overall coupled enzyme activity, target 2'-O- or 4'-O-beta-D-glucoside was obtained in >= 88% yield from reactions consisting of 5 mM dihydrochalcone acceptor, 100 mM sucrose, and 0.5 mM UDP. Davidioside and confusoside were isolated and their proposed chemical structures confirmed by NMR. OGT-SuSy cascade transformations present a green chemistry approach for efficient glucosylation in natural products synthesis.

关键词： synthesis dihydrochalcone user datagram protocol/internet protocol cascades Phloretin Natural products core structure Functional foods OGT gene Saccharose chemical synthesis Uridine Diphosphate

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Performance evaluation of OpenFlow controllers for network virtualization 15

Performance evaluation of OpenFlow controllers for network v...

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15th IEEE International Conference on High Performance Switching and Routing (HPSR)

作者： Turull, Daniel Hidell, Markus Sjodin, Peter KTH Royal Inst Technol Sch ICT Kista Sweden

ISBN: (纸本)9781479916337

This paper investigates OpenFlow performance, focusing on how the delay between switch and OpenFlow controller can impact the performance of a network. We use open-source controllers that support network virtualization to evaluate how such delay impacts ICMP, TCP and UDP traffic. We compare the controllers' flow set-up strategies and we conduct several experiments to compare their TCP and UDP performance. In addition, we introduce a new metric to measure UDP packet losses at the beginning of the flow. The results of the measurements indicate that there are large differences in performance between controllers, and that performance depends on switch-controller delay and flow set-up strategy.

关键词： Delays Loss measurement Ports (Computers) Switches Virtualization Virtualization loss measurement Switches Controllers delay Performance Evaluation user datagram protocol/internet protocol Uridine Diphosphate Tritolyl Phosphates tactical command post open source measurement result

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Hardware Architecture of an internet protocol Version 6 Processor 27

Hardware Architecture of an Internet Protocol Version 6 Proc...

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27th IEEE International System-on-Chip Conference (IEEE SOCC)

作者： Traskov, Boris Langenbach, Ulrich Hofmann, Klaus Gregorius, Peter Tech Univ Darmstadt Integrated Elect Syst Lab Darmstadt Germany Heinrich Hertz Inst Nachrichtentech Berlin GmbH Fraunhofer Inst Telecommun Berlin Germany

ISBN: (纸本)9781479933785

This paper presents the architecture of an internet protocol Version 6 processor for FPGA-based data processing and acquisition applications. Design choices and limitations are discussed together with a thorough simulation and verification methodology. The processor is demonstrated to frame and parse UDP over IPv6 traffic at 1Gb/s line-speed on a Virtex 5 FPGA, outperforming a reference soft-processor solution for UDP over IPv4. RTL-simulations show that 10Gb/s operation is attainable with the same architecture.

关键词： Buffer storage Hip internet Microarchitecture Pipelines Random access memory Registers BUFFER STORAGE random access machine IPv6 Registers Microarchitecture pipeline hardware architecture Hip internets user datagram protocol/internet protocol Uridine Diphosphate PROCESSOR piping

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Reliable Aeronautical Services protocol: Motivation, Design, and Performance

Reliable Aeronautical Services Protocol: Motivation, Design,...

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IEEE Global Communications Conference (GLOBECOM)

作者： Muhammad, Muhammad de Cola, Tomaso Kissling, Christian Berioli, Matteo Deutsch Zentrum Luft & Raumfahrt DLR Inst Commun & Nav D-82234 Wessling Oberpfaffenhofe Germany

ISBN: (纸本)9781479913534

The most widely used transport protocols (i.e, TCP and UDP) are not suitable for aeronautical services because of the reliability and strict transfer delay requirements that cannot be met by TCP and UDP in such environment. In this respect, the paper proposes a novel message-oriented transport protocol Reliable Aeronautical Services protocol (RASP) enabling reliable aeronautical services. Simulation campaigns carried out in ns-2 show the superiority of RASP with respect to TCP in terms of end-to-end message transfer delay and number of performed retransmissions.

关键词： Tritolyl Phosphates tactical command post transport protocols Rasps user datagram protocol/internet protocol Uridine Diphosphate Legal Services protocols message passing

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Comparative Performance Analysis of High-speed Transfer protocols for Big Data

Comparative Performance Analysis of High-speed Transfer Prot...

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38th Annual IEEE Conference on Local Computer Networks (LCN)

作者： Yu, Se-young Brownlee, Nevil Mahanti, Aniket Univ Auckland Dept Comp Sci Auckland 1 New Zealand

ISBN: (纸本)9781479905379

Researchers working in diverse fields such as astronomy, experimental physics, genomics, and meteorology have to frequently deal with analyzing voluminous amounts of complex data. Such data is often referred to as big data. These researchers work in teams and have to transfer this data over long distances. Efficiently transferring big data over long distances requires the use of appropriate transfer protocols. Several TCP-based and UDP-based protocols have been proposed in the literature, however, a comparative analysis of such protocols is lacking in the literature. This paper presents a comparative performance analysis of four well-known high-speed data transfer protocols for long fat networks, namely, GridFTP, FDT, UDT, and Tsunami. We performed extensive experiments to measure the effectiveness of each protocol in terms of its throughput for various round-trip times, and against increasing levels of congestion inducing TCP or UDP background traffic on a 10 Gb/s network. Our results show that without much tuning, TCP based protocols are able to achieve throughputs of more than 2 Gb/s. In presence of background traffic, UDP protocols perform better.

关键词： big data transfer protocol protocols Task Performance and Analysis system performance analysis Suppliers files Throughput Remote high speed data tsunamis Meteorology user datagram protocol/internet protocol Uridine Diphosphate

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Multi-UAV Testbed for Aerial Manipulation Applications

Multi-UAV Testbed for Aerial Manipulation Applications

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International Conference on Unmanned Aircraft Systems

作者： D. I. Montufar F. Munoz E. S. Espinoza O. Garcia S. Salazar Polytechnic University of Pachuca Aerospace Engineering Research and Innovation Center CIIIA-FIME-UANL The French-Mexican Laboratory on Computer Science and Control LAFMIA-UMI CNRS 3175 CINVESTAV-IPN

ISBN: (纸本)9781479923779

This paper addresses the development and implementation of a testbed for object's manipulation by using unmanned aerial vehicles *** and the VICON Cameras System. Such testbed allows the user to choose among two development environments to perform aerial manipulation establishing a communication with LabVIEW, ROS and the C++ Qt library;thus, the user can employ the development environment more suitable for his application. This testbed allows us to establish communication between a computer and the A.R. Drone (v1 or v2) via a WiFi connection which sends and receives data using the communication protocol UDP and sockets for connection with the vehicle UDP ports. This platform sends control and navigation commands to the UAVs in order to position them in the space with user interaction by means of a graphical user interface. This testbed enables the implementation of more complex applications, such as complex controllers. In addition, to validate the effectiveness of this testbed, experimental results of aerial manipulation between two quadrotors are presented.

关键词： Communication Research user-computer interaction ANTENNA test bed Unmanned Aerial Vehicle drone honey bees Computers user datagram protocol/internet protocol Uridine Diphosphate

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internet delays and packet losses sensor/actuator for UDP based Networked Control Systems

Internet delays and packet losses sensor/actuator for UDP ba...

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Mediterranean Conference on Control & Automation

作者： Miguel Diaz-Cacho Emma Delgado Antonio Barreiro School of Computer Engineering University of Vigo School of Industrial Engineering University of Vigo

ISBN: (纸本)9781479909964

The performance of networked control systems (NCS) in non-deterministic networks, such as the internet depends largely on the network delays and packet losses. The reproduction of these delays and packet losses in a NCS implies the use of network simulators and emulators. In this paper, a system that performs as a sensor and as an actuator of internet delays and packet losses is presented. It collects these parameters from the internet and reproduces them into a local network data flow. The paper presents some comparative results and makes a performance analysis of the whole system.

关键词： Packet loss Networked control systems internets network delay user datagram protocol/internet protocol Uridine Diphosphate Emulators control systems delay network simulator actuators

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Design of embedded voice communication system

Design of embedded voice communication system

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IET International Conference on Smart and Sustainable City 2013 (ICSSC 2013)

作者： Xuzhi Wang Wenzhen Zhang Xiangfei Li Shanghai University Shanghai Shanghai CN

ISBN: (纸本)9781629938219

Voice communication is the most basic and important means to people directly exchange. Meanwhile, with the development of embedded systems, where the mobile phones, televisions, set-top boxes and other home electronics and communication products and even electric transport control core are all closely related to embedded systems. This paper describes the design and implementation of a multi-way voice communication system with the internet protocol of UDP, using S3C2440A as the control core and other Peripheral Circuits realize the voice processing and transition functions. Experiments show that the system not only can meet the fast processing, but also meet the requirements of small and portable.

关键词： Embedded System PCM Coded UDP protocol Voice Communication Embedded systems voice communication system Voice communication Speech processing internet protocol user datagram protocol/internet protocol Uridine Diphosphate

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A Location-Independent Direct Link Neuromorphic Interface

A Location-Independent Direct Link Neuromorphic Interface

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International Joint Conference on Neural Networks

作者： Alexander D. Rast Johannes Partzsch Christian Mayr Johannes Schemmel Stefan Hartmann Luis A. Plana Steve Temple David R. Lester Rene Schüffny Steve Furber School of Computer Science The University of Manchester Manchester UK Heidelberg University Heidelberg Germany

ISBN: (纸本)9781467361279

With neuromorphic hardware rapidly moving towards large-scale, possibly immovable systems capable of implementing brain-scale neural models in hardware, there is an emerging need to be able to integrate multi-system combinations of sensors and cortical processors over distributed, multisite configurations. If there were a standard, direct interface allowing large systems to communicate using native signalling, it would be possible to use heterogeneous resources efficiently according to their task suitability. We propose a UDP-based AER spiking interface that permits direct bidirectional spike communications over standard networks, and demonstrate a practical implementation with two large-scale neuromorphic systems, BrainScaleS and SpiNNaker. Internally, the interfaces at either end appear as interceptors which decode and encode spikes in a standardised AER address format onto UDP frames. The system is able to run a spiking neural network distributed over the two systems, in both a side-by-side setup with a direct cable link and over the internet between 2 widely spaced sites. Such a model not only realises a solution for connecting remote sensors or processors to a large, central neuromorphic simulation platform, but also opens possibilities for interesting automated remote neural control, such as parameter tuning, for large, complex neural systems, and suggests methods to overcome differences in timescale and simulation model between different platforms. With its entirely standard protocol and physical layer, the interface makes large neuromorphic systems a distributed, accessible resource available to all.

关键词： integrate multi-system combinations physical layer interface Physical layer Neuromorphics Interface Interfaces Interceptor aircraft DECODING PROCESSOR user datagram protocol/internet protocol Uridine Diphosphate Computer hardware COMMUNICATING Permit

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