| 1. |
- Beck, R., et al.
(författare)
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GPSDTN : Predictive velocity-enabled delay-tolerant networks for arctic research and sustainability
- 2007
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Ingår i: Second International Conference on Internet Monitoring and Protection (ICIMP 2007). - Los Alamitos, Calif : IEEE Computer Society Press. - 9780769529110
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Konferensbidrag (refereegranskat)abstract
- A Delay-Tolerant Network (DTN) is a necessity for communication nodes that may need to wait for long periods to form networks. The IETF Delay Tolerant Network Research Group is developing protocols to enable such networks for a broad variety of Earth and interplanetary applications. The Arctic would benefit from a predictive velocity-enabled version of DTN that would facilitate communications between sparse, ephemeral, often mobile and extremely power-limited nodes. We propose to augment DTN with power-aware, buffer-aware location- and time-based predictive routing for ad-hoc meshes to create networks that are inherently location and time (velocity) aware at the network level to support climate research, emergency services and rural education in the Arctic. On Earth, the primary source of location and universal time information for networks is the Global Positioning System (GPS). We refer to this Arctic velocity-enabled Delay-Tolerant Network protocol as "GPSDTN" accordingly. This paper describes our requirements analysis and general implementation strategy for GPSDTN to support Arctic research and sustainability efforts
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| 2. |
- Ejiri, M.K., et al.
(författare)
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Validation of the Improved Limb Atmospheric Spectrometer-II (ILAS-II) Version 1.4 nitrous oxide and methane profiles
- 2006
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 111:D22
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Tidskriftsartikel (refereegranskat)abstract
- This study assesses polar stratospheric nitrous oxide (N(2)O) and methane (CH(4)) data from the Improved Limb Atmospheric Spectrometer-II (ILAS-II) on board the Advanced Earth Observing Satellite-II (ADEOS-II) retrieved by the Version 1.4 retrieval algorithm. The data were measured between January and October 2003. Vertical profiles of ILAS-II volume mixing ratio (VMR) data are compared with data from two balloon-borne instruments, the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS-B) and the MkIV instrument, as well as with two satellite sensors, the Odin Sub-Millimetre Radiometer (SMR) for N(2)O and the Halogen Occultation Experiment (HALOE) for CH(4). Relative percentage differences between the ILAS-II and balloon/satellite data and their median values are calculated in 10-ppbv-wide bins for N(2)O (from 0 to 400 ppbv) and in 0.05-ppmv-wide bins for CH(4) (from 0 to 2 ppmv) in order to assess systematic differences between the ILAS-II and balloon/satellite data. According to this study, the characteristics of the ILAS-II Version 1.4 N(2)O and CH(4) data differ between hemispheres. For ILAS-II N(2)O VMR larger than 250 ppbv, the ILAS-II N(2)O agrees with the balloon/SMR N(2)O within +/- 20% in both hemispheres. The ILAS-II N(2)O in the VMR range from 30-50 to 250 ppbv (corresponding to altitudes of similar to 17-30 km in the Northern Hemisphere (NH, mainly outside the polar vortex) and similar to 13-21 km in the Southern Hemisphere (SH, mainly inside the polar vortex) is smaller by similar to 10-30% than the balloon/SMR N(2)O. For ILAS-II N(2)O VMR smaller than 30 ppbv (>similar to 21 km) in the SH, the differences between the ILAS-II and SMR N(2)O are within +/- 10 ppbv. For ILAS-II CH(4) VMR larger than 1 ppmv (similar to 30 km) and the ILAS-II CH(4) for its VMR smaller than 1 ppmv (>similar to 25 km) only in the NH, are abnormally small compared to the balloon/satellite data.
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| 3. |
- Mufti, A.A., et al.
(författare)
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New Canadian highway bridge design code design provisions for fibre-reinforced structures
- 2007
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Ingår i: Canadian journal of civil engineering (Print). - 0315-1468 .- 1208-6029. ; 34:3, s. 267-283
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a synthesis of the design provisions of the second edition of the Canadian Highway Bridge Design Code (CHBDC) for fibre-reinforced structures. New design provisions for applications not covered by the first edition of the CHBDC and the rationale for those that remain unchanged from the first edition are given. Among the new design provisions are those for glass-fibre-reinforced polymer as both primary reinforcement and tendons in concrete; and for the rehabilitation of concrete and timber structures with externally bonded fibre-reinforced-polymer (FRP) systems or near-surface-mounted reinforcement. The provisions for fibre-reinforced concrete deck slabs in the first edition have been reorganized in the second edition to explicitly include deck slabs of both cast-in-place and precast construction and are now referred to as externally restrained deck slabs, whereas deck slabs containing internal FRP reinforcement are referred to as internally restrained deck slabs. Resistance factors in the second edition have been recast from those in the first edition and depend on the condition of use, with a further distinction made between factory- and field-produced FRP. In the second edition, the deformability requirements for FRP-reinforced and FRP-prestressed concrete beams and slabs of the first edition have been split into three subclauses covering the design for deformability, minimum flexural resistance, and crack-control reinforcement. The effect of sustained loads on the strength of FRPs is accounted for in the second edition by limits on stresses in FRP at the serviceability limit state.
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