3,462 research outputs found
Modelling and controller design of inductor-coupled multimodule DC-DC convertor with master-slave current-comparing scheme
No full textEcology of the Festuca Grassland in Central Saskatchewan
Full text linkFor some time it has been realized that the grassland occuring in the 'park belt' or 'aspen grove region' bounding the Canadian prairies on the north, and forming the transition between it and the boreal forest, does not consist merely of extensions of the adjacent grassland communities (true prairie or mixed prairie) among the patches of woodland which occur in that region; but is characterized by a different group of dominant grasses from those occuring elsewhere in North America.
Although other investigators have mentioned this fact and written about the flora in other parts of the region, their data have been based largely on methods of estimation chiefly of a qualitative nature. In view of this, it was thought that an ecological survey based on quantitative methods might provide a better basis for classifying the vegetation of the area.
Accordingly, while being employed as an assistant in the Department of Plant Ecology of the University of Saskatchewan the author was given the opportunity, under the supervision of Dr. R.T. Coupland, to carry out investigations in those parts of the aspen grove region north and northwest of Saskatoon.
The author is considerably indebted to Dr. B.W. Currie of the Physics Department, for furnishing data on the climate of the area of research, and to Mr. H.C. Moss and his assistants, of the Saskachewan Soil Survey, who kindly undertook to examine and report on the soil samples which were collected in several of the sites studied. The author also wishes to express his gratitide to Mr. Jack F. Alex and Mr. W. Budz of the Department of Plant Ecology, who assisted greatly in both the field and laboratory work for this project. The financial assistance of the Saskatchewan Agricultural Research Foundation, which made this study possible, is also appreciated.
The author experienced a great deal of difficulty as a result of unfamiliarity with the topography, in particular with the vegetation of the plants, since he is more accustomed to the mountains and forests of British Columbia. Many problems of identifications were encountered in dealing with the wealth of species of grasses and composites, as well as problems of relationship between the communities found in certain locations and their topographical situation
Amplification refractory mutation system (ARMS), a highly sensitive and simple PCR assay for the detection of JAK2 V617F mutation in chronic myeloproliferative disorders
No full textFlip-chip joined 8X8 array of bottom-emitting 850-nm light-emitting diodes for interconnect applications
No full textWe present an array of GaAs-based light-emitting diodes emitting at 850 nm, which is designed to be flip-chip joined on carriers like a silicon CMOS circuit. The light-emitting diodes are grown by MBE. After processing of the array and flip-chip joining using Indium-bumps, the substrate of the LED array is removed completely. Individual light-emitting diodes reach an external quantum efficiency of 3.3% after the complete process.status: Publishe
Optics in computers servers and data centers
No full textBased on well-known laws of physics, a lower bound on the energy-per-bit required for transmitting information using a photonic channel is established. The analysis includes the energy required to convert information from the electronic to the photonic domain and back. We investigate links that employ a directly modulated laser as well as links that employ an external modulator. It is shown that the power dissipation of the channel also imposes a bound on the maximum bandwidth density for a photonic link. Keeping this in mind, opportunities for optics in computing systems are discussed, especially from a systems perspective
Design and implementation of an electro-optical backplane with pluggable in-plane connectors
No full textThe design, implementation and characterisation of an electro-optical
backplane and an active pluggable in-plane optical connector technology
is presented. The connection architecture adopted allows line cards to
be mated to and unmated from a passive electro-optical backplane with
embedded polymeric waveguides. The active connectors incorporate a
photonics interface operating at 850 nm and a mechanism to passively
align the interface to the optical waveguides embedded in the backplane.
A demonstration platform has been constructed to assess the viability of
embedded electro-optical backplane technology in dense data storage
systems. The demonstration platform includes four switch cards, which
connect both optically and electronically to the electro-optical backplane
in a chassis. These switch cards are controlled by a single board
computer across a Compact PCI bus on the backplane. The electrooptical
backplane is comprised of copper layers for power and low speed
bus communication and one polymeric optical layer, wherein waveguides
have been patterned by a direct laser writing scheme. The optical
waveguide design includes densely arrayed multimode waveguides with
a centre to centre pitch of 250μm between adjacent channels, multiple
cascaded waveguide bends, non-orthogonal crossovers and in-plane
connector interfaces. In addition, a novel passive alignment method
has been employed to simplify high precision assembly of the optical
receptacles on the backplane. The in-plane connector interface is based
on a two lens free space coupling solution, which reduces susceptibility
to contamination. Successful transfer of 10.3 Gb/s data along multiple
waveguides in the electro-optical backplane has been demonstrated and
characterised
Coordination in an Adaptive Traffic Signal Control System
No full textCoordination between the intersections is used in traffic signal control for quite a long time. The objective of this thesis is to determine how beneficial network coordination is in an adaptive traffic signal control system that follows the multi-agent approach. As part of the research: Simulation results show that coordination in a multi-agent controller can reduce average delay of the users on the network depending on the average demand. The best performing coordination measure is platooning cars on the main streams at the first intersection of the arterial. This provide time for the downstream intersections to serve side streams and ensured that the main stream is not stopped at the downstream intersections on the arterial. The tested coordination measures reduced delay with 10% compared to the original settings.Transport and PlanningTransport & PlanningCivil Engineering and Geoscience
Block-Adaptive Kernel-Based CDMA Multiuser Detector
No full textThe paper investigates the application of a recently introduced learning technique, called the relevance vector machine (RVM) to construct a block-adaptive kernel-based nonlinear multiuser detector (MUD) for direct-sequence code-division multiple-access (DS-CDMA) signals transmitted through multipath channels. It is demonstrated that the RVM MUD can closely match the performance of the optimal Bayesian one-shot detector, with a much sparser kernel representation than that is achievable by the state-of-art support vector machine (SVM) technique
The implementation of a system description language and its semantic functions
No full textElectrical Engineering, Mathematics and Computer Scienc
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