135,059 research outputs found
The IT performance evaluation in the construction industry
To date there has been limited published work in
the construction management and engineering
literature that has provided empirical evidence to
demonstrate that IT can improve organizational
performance. Without an explicit understanding
about how IT can be effectively used to improve
organizational performance, its justification will
remain to be weak for managers. To ensure the
continuous increase in IT based applications in the
construction industry, sufficient evidence has to be
provided for management in various professions of
the construction industry to evaluate, allocate and
utilize appropriate IT systems. In an attempt to
explore the relationship between IT and
productivity, an empirical investigation of 60
Professional Consulting Firms (PCF) from the
Hong Kong construction industry was undertaken.
A model for determining the organizational
productivity of IT is proposed, and the
methodology used to test the model is described.
The findings are analyzed and a cross-profession
comparison of the results indicated the differences
in the use of IT. The research findings are discussed
with similarities being drawn. The limitations of the
research are then presented and discussed. The
implications of the findings and conclusions then
fully presented
Ground Band and a Generalized GP-equation for Spinor Bose-Einstein Condensates
For the spinor Bose-Einstein condensates both the total spin and its
Z-component should be conserved. However, in existing theories, only
the conservation of has been taken into account. To remedy, this paper
is the first attempt to take the conservation of both and into
account. For this purpose, a total spin-state with the good quantum numbers
and is introduced in the trial wave function, thereby a generalized
Gross-Pitaevskii equation has been derived. With this new equation, the ground
bands of the Na and Rb condensates have been studied, where the
levels distinct in split. It was found that the level density is extremely
dense in the bottom of the ground band of Na, i.e., in the vicinity of
the ground state. On the contrary, for Rb, the levels are extremely
dense in the top of the ground band,Comment: 7 page, 5 figure
Quasiparticles dynamics in high-temperature superconductors far from equilibrium: an indication of pairing amplitude without phase coherence
We perform time resolved photoelectron spectroscopy measurements of optimally
doped \tn{Bi}_2\tn{Sr}_2\tn{CaCu}_2\tn{O}_{8+\delta} (Bi-2212) and
\tn{Bi}_2\tn{Sr}_{2-x}\tn{La}_{x}\tn{Cu}\tn{O}_{6+\delta} (Bi-2201). The
electrons dynamics show that inelastic scattering by nodal quasiparticles
decreases when the temperature is lowered below the critical value of the
superconducting phase transition. This drop of electronic dissipation is
astonishingly robust and survives to photoexcitation densities much larger than
the value sustained by long-range superconductivity. The unconventional
behaviour of quasiparticle scattering is ascribed to superconducting
correlations extending on a length scale comparable to the inelastic path. Our
measurements indicate that strongly driven superconductors enter in a regime
without phase coherence but finite pairing amplitude. The latter vanishes near
to the critical temperature and has no evident link with the pseudogap observed
by Angle Resolved Photoelectron Spectroscopy (ARPES).Comment: 7 pages, 5 Figure
Advanced InSAR atmospheric correction: MERIS/MODIS combination and stacked water vapour models
A major source of error for repeat-pass Interferometric Synthetic Aperture Radar (InSAR) is the phase delay in radio signal propagation through the atmosphere (especially the part due to tropospheric water vapour). Based on experience with the Global Positioning System (GPS)/Moderate Resolution Imaging Spectroradiometer (MODIS) integrated model and the Medium Resolution Imaging Spectrometer (MERIS) correction model, two new advanced InSAR water vapour correction models are demonstrated using both MERIS and MODIS data: (1) the MERIS/MODIS combination correction model (MMCC); and (2) the MERIS/MODIS stacked correction model (MMSC). The applications of both the MMCC and MMSC models to ENVISAT Advanced Synthetic Aperture Radar (ASAR) data over the Southern California Integrated GPS Network (SCIGN) region showed a significant reduction in water vapour effects on ASAR interferograms, with the root mean square (RMS) differences between GPS- and InSAR-derived range changes in the line-of-sight (LOS) direction
decreasing from ,10mm before correction to ,5mm after correction, which is similar to the GPS/MODIS integrated and MERIS correction models. It is expected that these two advanced water vapour correction models can expand the application of MERIS and MODIS data for InSAR atmospheric correction. A simple but effective approach has been developed to destripe Terra MODIS images contaminated by radiometric calibration errors. Another two limiting factors on the MMCC and MMSC models have also been investigated in this paper: (1) the impact of the time difference between MODIS and SAR data; and (2) the frequency of cloud-free conditions at the global scale
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