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933 results on '"Cotter D"'

105. Designing a multi-hop regular virtual topology for ultrafast optical packet switching : node placement optimisation and/or dilation minimisation?

Author

Komolafe, O., Harle, D.A., and Cotter, D.

Subjects
TK
Abstract

This paper studies the design of multi-hop regular virtual topologies to facilitate optical packet switching in networks with arbitrary physical topologies. The inputs to the virtual topology design problem are the physical topology, the traffic matrix and the regular topology. In this paper, this problem is tackled directly and also by decomposition into two sub-problems. The first sub-problem, dilation minimisation, uses only the physical topology and the virtual topology as optimisation inputs. The second sub-problem considers the traffic matrix and virtual topology as optimisation inputs. The solutions of these two sub-problems are compared with each other and against the results obtained when the global problem is optimised (using all three possible input parameters) for a variety of traffic scenarios. This gives insight into the key question of whether the physical topology or the traffic matrix is the more important parameter when designing a regular virtual topology for optical packet switching. Regardless of the approach taken the problem is intractable and hence heuristics must be used to find (near) optimal solutions in reasonable time. Five different optimisation heuristics, using different artificial intelligence techniques, are employed in this paper. The results obtained by the heuristics for the three alternative design approaches are compared under a variety of traffic scenarios. An important conclusion of this paper is that the traffic matrix plays a less significant role than is conventionally assumed, and only a marginal penalty is incurred by disregarding it in several of the traffic cases considered.

Published
2001

106. Optical grooming switch with regenerative functionality for transparent interconnection of networks

Author

Vorreau, P., Sygletos, S., Parmigiani, F., Hillerkuss, D., Bonk, R., Petropoulos, P., Richardson, D.J., Zarris, G., Simeonidou, D., Klonidis, D., Tomkos, I., Weerasuriya, R., Ibrahim, S.K., Ellis, A.D., Cotter, D., Morais, R., Monteiro, P., Ben Ezra, S., Tsadka, S., Freude, W., Leuthold, Juerg, Vorreau, P., Sygletos, S., Parmigiani, F., Hillerkuss, D., Bonk, R., Petropoulos, P., Richardson, D.J., Zarris, G., Simeonidou, D., Klonidis, D., Tomkos, I., Weerasuriya, R., Ibrahim, S.K., Ellis, A.D., Cotter, D., Morais, R., Monteiro, P., Ben Ezra, S., Tsadka, S., Freude, W., and Leuthold, Juerg

Abstract

We demonstrate a regenerative optical grooming switch for buffer-less interconnection of metro/access and metro/core ring networks with switching functionality in time, space and wavelength domain. Key functionalities of the router are the traffic aggregation with time-slot interchanging (TSI) functionality, the WDM-to-ODTM multiplexing and the OTDM-to-WDM demultiplexing of high-speed channel into lower bit-rate tributaries as well as multi-wavelength all-optical 2R regeneration of several higher-speed signals. BER and Q-factor measurements of different switching scenarios show excellent performance with no error floor and Q-factors above 21 dB.

Published
2009

107. Response to M Krkošek, C W Revie, B Finstad and C D Todd's comment on Jackson et al . ‘Impact of L epeophtheirus salmonis infestations on migrating Atlantic salmon, S almo salar L., smolts at eight locations in Ireland with an analysis of lice‐induced marine mortality’

Author

Jackson, D, primary, Cotter, D, additional, Newell, J, additional, O'Donohoe, P, additional, Kane, F, additional, McDermott, T, additional, Kelly, S, additional, and Drumm, A, additional

Published
2014
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109. 40 Gbit/s asynchronous digital optical regenerator

Author

Hillerkuss, D., Ellis, A., Zarris, G., Simeonidou, D., Leuthold, J., Cotter, D., Hillerkuss, D., Ellis, A., Zarris, G., Simeonidou, D., Leuthold, J., and Cotter, D.

Abstract

We present the first experimental demonstration of an asynchronous digital optical regenerator at 42.67 Gbit/s. The system effectively retimes incoming asynchronous data bursts to a local clock without burst mode clock recovery and converts the signal to a desired wavelength and duty cycle.

Published
2008

110. Optical packet transmission in 42.6 Gbit/s wavelength-division-multiplexed clockwork-routed networks

Author

Bravi, E., Ellis, Andrew D., Mishra, Arvind K., Cotter, D., Bravi, E., Ellis, Andrew D., Mishra, Arvind K., and Cotter, D.

Abstract

The use of amplitude-modulated phase-shift-keyed (AM-PSK) optical data transmission is investigated in a sequence of concatenated links in a wavelength-division-multiplexed clockwork-routed network. The narrower channel spacing made possible by using AM-PSK format allows the network to contain a greater number of network nodes. Full differential precoding at the packet source reduces the amount of high-speed electronics required in the network and also offers simplified header recognition and time-to-live mechanisms.

Published
2008

111. Spectrally compact optical subcarrier multiplexing with 42.6 Gbit/s AM-PSK payload and 2.5Gbit/s NRZ labels

Author

Mishra, A.K., Ellis, A.D., Cotter, D., Smyth, Frank, Connolly, Eoin M., Barry, Liam P., Mishra, A.K., Ellis, A.D., Cotter, D., Smyth, Frank, Connolly, Eoin M., and Barry, Liam P.

Abstract

A novel approach to optical subcarrier multiplexing with compact spectrum is demonstrated using a 42.6 Gbit/s AM-PSK payload and 2.5 Gbit/s NRZ label. In this implementation, the payload introduces a 4.8 dB penalty on the label receiver sensitivity, and the label causes <1 dB penalty on the payload receiver sensitivity.

Published
2006

112. SCM optical label switching scheme in a WDM packet transmitter employing a switching SG-DBR laser

Author

Smyth, Frank, Mishra, A.K., Connolly, Eoin M., Ellis, A.D., Cotter, D., Kaszubowska-Anandarajah, Aleksandra, Barry, Liam P., Smyth, Frank, Mishra, A.K., Connolly, Eoin M., Ellis, A.D., Cotter, D., Kaszubowska-Anandarajah, Aleksandra, and Barry, Liam P.

Abstract

We demonstrate an SCM optical label switching scheme with spectral efficiency of 0.4bit/s/Hz and a spectral density figure of merit of 1. We then employ this scheme in a WDM transmitter subsystem and we investigate the detrimental effects that switching events in tunable lasers can have on such systems. The label performance is shown to hit an error floor when the tunable laser switches channels and this would cause incorrect routing of packets. The bit error rate is time resolved in order to better understand the problem and some possible solutions are discussed.

Published
2006
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115. Contemporary Nonlinear Optics

Author

Cotter, D.

Subjects
Contemporary Nonlinear Optics (Book) -- Book reviews, Books -- Book reviews, Physics
Published
1992

124. Optical grooming switch with regenerative functionality for transparent interconnection of networks

Author

Vorreau, P., primary, Sygletos, S., additional, Parmigiani, F., additional, Hillerkuss, D., additional, Bonk, R., additional, Petropoulos, P., additional, Richardson, D. J., additional, Zarris, G., additional, Simeonidou, D., additional, Klonidis, D., additional, Tomkos, I., additional, Weerasuriya, R., additional, Ibrahim, S., additional, Ellis, A. D., additional, Cotter, D., additional, Morais, R., additional, Monteiro, P., additional, Ben Ezra, S., additional, Tsadka, S., additional, Freude, W., additional, and Leuthold, J., additional

Published
2009
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131. ENVIROSAT-2000 report: Federal agency satellite requirements

Author

Cotter, D, Wolzer, I, Blake, N, Jarman, J, Lichy, D, Pangburn, T, Mcardle, R, Paul, C, Shaffer, L, and Thorley, G

Subjects
Spacecraft Design, Testing And Performance
Abstract

The requirement of Federal agencies, other than NOAA, for the data and services of civil operational environmental satellites (both polar orbiting and geostationary) are summarized. Agency plans for taking advantage of proposed future Earth sensing space systems, domestic and foreign, are cited also. Current data uses and future requirements are addressed as identified by each agency.

Published
1985

132. Operational LANDSAT remote sensing system development

Author

Cotter, D. J

Subjects
Earth Resources And Remote Sensing
Abstract

The reduction of $121.6 million dollars from NOAA's LANDSAT development program for FY 1982, and the shortened time period for transferring remote sensing technology to the private sector resulted in changes in the Agency's plans for managing the operational system. Proposed legislation for congressional consideration or enactment to establish conditions under which this private sector transfer will occur, and the expected gradual rise in the price of data products are discussed. No money exists for capital investment and none is projected for investing in an operational data handling system for the LANDSAT D satellite. Candidates knowledgeable of various aspects of the needs and uses of remote sensing are urged to consider participation in NOAA's advisory committee.

Published
1981

136. Optical interconnection of core and metro networks [Invited]

Author

Ellis, A. D., primary, Cotter, D., additional, Ibrahim, S., additional, Weerasuriya, R., additional, Chow, C. W., additional, Leuthold, J., additional, Freude, W., additional, Sygletos, S., additional, Vorreau, P., additional, Bonk, R., additional, Hillerkuss, D., additional, Tomkos, I., additional, Tzanakaki, A., additional, Kouloumentas, C., additional, Richardson, D. J., additional, Petropoulos, P., additional, Parmigiani, F., additional, Zarris, G., additional, and Simeonidou, D., additional

Published
2008
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140. An all-optical grooming switch to interconnect access and metro ring networks

Author

Leuthold, J., primary, Freude, W., additional, Sygletos, S., additional, Vorreau, P., additional, Bonk, R., additional, Hillerkuss, D., additional, Tomkos, I., additional, Tzanakaki, A., additional, Kouloumentas, C., additional, Richardson, D. J., additional, Petropoulos, P., additional, Parmigiani, F., additional, Ellis, A., additional, Cotter, D., additional, Ibrahim, S., additional, and Weerasuriya, R., additional

Published
2008
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149. LMSD: LIPID MAPS structure database

Author

Sud, M., primary, Fahy, E., additional, Cotter, D., additional, Brown, A., additional, Dennis, E. A., additional, Glass, C. K., additional, Merrill, A. H., additional, Murphy, R. C., additional, Raetz, C. R. H., additional, Russell, D. W., additional, and Subramaniam, S., additional

Published
2007
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