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101.
IrBurst is a session/presentation layer protocol dedicated for high speed large volume information transfer over IrDA links.
The protocol is developed by IrDA in order to complement the existing protocol OBEX which is best suited for small files.
This paper presents a mathematical model for IrBurst over the IrDA protocol stacks taking into account the presence of bit
errors and multiple simultaneously applications. The performance of IrBurst is examined considering TinyTP buffer sizes and
the number of IrBurst application connections as parameters. The contribution of this work is to develop a mathematical model
for IrBurst, investigate the compatibility of IrBurst to low layer protocols, as well as providing suitable design guidelines
for IrDA devices for high performance of IrBurst.
Pi Huang received the B.Sc. degree in Electrical and Electronic Engineering from University of Central Lancashire, U.K., in 2001, the M.Sc.
degree in Telecommunications from University College London, U.K., in 2002 and the Ph.D degree in the Personal Wireless Networks
and Outdoor Optical Links from Bournemouth University, U.K., in 2006. He is currently working in wireless solution division
of British Telecom. His research focuses on performance modelling and analysis as well as discrete-event simulation of wireless
communication protocols and wireless communication networks. He has published over 20 papers in the areas of wireless communications.
Anthony C. Boucouvalas has worked at GEC Hirst Research Centre, and became Group Leader and Divisional Chief Scientist until 1987, when he joined
Hewlett Packard (HP) Laboratories as Project Manager. He joined Bournemouth University in 1994 and became a Professor in Multimedia
Communications in 1996, and in 1999 became Director of the Microelectronics and Multimedia Research Centre. His current research
interests span the fields of wireless communications, optical fibre communications and components, multimedia communications,
and human-computer interfaces, where he has published over 200 papers. He has contributed to the formation of IrDA as an industry
standard and he is now a Member of the IrDA Architectures Council. He is a Fellow of Fellow of the Royal Society for the encouragement
of Arts, Manufacturers and Commerce, (FRSA) and a Fellow of IEE, (FIEE). In 2002 he became a Fellow of the Institute of Electrical
and Electronic Engineers (FIEEE), for contributions to optical fibre components and optical wireless communications. He is
an Editor of numerous Journals and in the Organising committee of many conferences. 相似文献
102.
Frédéric Caupin Francesco Ancilotto Manuel Barranco Ricardo Mayol Marti Pi 《Journal of Low Temperature Physics》2007,148(5-6):731-736
Solidification of superfluid helium-4 has been addressed within the framework of density functional theory. Early studies
used a variational approach, approximating the density distribution in the solid phase by a sum of Gaussians on each lattice
site. Recently, we performed an unconstrained minimization of the functional describing the helium system as reported by Ancilotto
et al. (Phys. Rev. B, 72, 214522, 2005). At sufficiently high density, we find stable solid like solutions, which exhibit an anisotropic density profile around
each lattice site. We compare these results to the previous variational approach, and attempt to improve the family of trial
functions by adding a variational parameter to account for anisotropy. 相似文献
103.
104.
There have been many studies focusing on individuals’ knowledge sharing behavior in the organizational setting. With the rapid prevalence of social networking sites, many people began to express their thoughts or share their knowledge via Facebook website. Facebook is an open environment which does not provide any immediate monetary benefits to its users. Its Groups members’ knowledge sharing behavior could be different from the ones in organizations. We proposed a research model to examine factors which promote the Facebook Groups users’ willingness to share knowledge. The factors in the study include extrinsic motivation, social and psychological forces, and social networking sharing culture. We used PLS to test our proposed hypotheses based on 271 responses collected through an online survey. Our results indicated that reputation would affect knowledge sharing attitude of Groups members and sense of self-worth would directly and indirectly (through subjective norm) affect the attitude. In addition, social networking sharing culture (fairness, identification, and openness) is the most significant factor, not only directly affecting knowledge sharing intention, but also indirectly influencing the sharing intention through subjective norm and knowledge sharing attitude. 相似文献
105.
As regards river restoration, it is fundamental to better link human pressures and environmental responses and to take into consideration not only target species or habitat but diverse ecological elements. This permits to assess sustainable restoration plan, especially concerning sediment augmentation below dams. The use of a hierarchical multicriteria approach on the Ain River permits us to assess a diagnosis of sediment deficit impact integrating several morphological (channel shifting, river bed degradation and river bed coarsening) and ecological components (Riparian and floodplain lake and fish communities). Our diagnosis also integrates a temporal and spatial approach better to link human pressures and environmental responses and to identify the dam effects amongst other drivers (e.g. grazing decline and channel regulation). The results confirm causality links between sediment deficit and slight channel bed degradation (0.01 m.year?1) or channel bed paving and thus highlight the impact of the dam on the drying of the riparian forest and on former channel community. However, the relationship between incision and reduction in active channel lateral mobility is more difficult to establish. The role of sediment deficit in the current variability of the riparian regeneration capacity and, thereby, landscape diversity along the lower valley remains unclear. This study also confirms the relevance of using different ecological indicators, notably because all components present different adjustment time scales, whereas some of them are more sensitive to other impacts. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
106.
107.
Martín Durante Martín Oesterheld Gervasio Piñeiro María Mercedes Vassallo 《International journal of remote sensing》2013,34(9):2963-2981
Assessing forage quantity and quality through remote sensing can facilitate grassland and pasture management. However, the high spatial and temporal variability of canopy conditions may limit the predictive accuracy of models based on reflectance measurements. The objective of this work was to develop this type of models, and to challenge their capacity to predict plant properties under a wide range of environmental conditions. We manipulated Paspalum dilatatum canopies through different stress treatments (flooding, drought, nutrient availability, and control) and by artificially varying the amount of senescent biomass. We measured canopy reflectance and constructed simple models, based on either normalized vegetation indices or a few selected wavebands, to estimate biomass and two variables related to forage quality: proportion of photosynthetic vegetation and biomass C:N ratio. General models satisfactorily predicted plant properties for the whole set of environmental conditions, but failed under specific conditions such as drought (for estimates of plant biomass), fertilization (for estimates of C:N ratio), and different levels of senescent tillers (for estimates of the proportion of photosynthetic vegetation). Where general models failed, specific models, based on different bands, achieved satisfactory accuracy. The general models performed better when based on a few selected bands than when based on two-band vegetation indices, having better accuracy (higher R2) and parsimony (lower BIC). However specific models performed similarly for both approaches (similar R2 and BIC). These results indicate that these plant properties can be predicted from reflectance information under a broad range of conditions, but not for some particular conditions, where ancillary data or more complex models are probably needed to increase predictive accuracy. 相似文献
108.
Vincent Wawrzyniak Hervé Piégay Pascal Allemand Lise Vaudor Philippe Grandjean 《International journal of remote sensing》2013,34(13):4812-4831
Braided rivers exhibit high spatial thermal heterogeneity that is difficult to understand using only in situ measurements. In this summer study, we used a drone and a powered paraglider to acquire very high spatial resolution (14–27 cm) thermal infrared (TIR) images of nine braided reaches located in the French Alps. We applied atmospheric corrections to TIR images and calibrated them based on in situ data. To characterize spatial and temporal thermal patterns, three temporal approaches were applied. A single survey of each site was performed to comparatively explore the nine braided reaches. Three reaches were imaged twice, in 2010 and 2011, to explore inter-annual variability. Finally, two reaches were selected for an intra-day survey for which four and three flights, respectively, were realized within one day. We reported two types of thermal patterns in braided reaches, the first showing very low thermal variability throughout the day. This low variability was linked to the low diversity found in the aquatic habitat, notably due to proglacial regimes with high summer flows which homogenize water temperatures. The second type exhibited a higher thermal variability with changes during the day. The temperature of flowing channels changed during the daytime according to air temperature. In contrast, the temperature of channels downstream connected to the main network exhibited smaller changes, which created thermal variability over space and time associated with hyporheic or phreatic flows. Non-proglacial and proglacial reaches behaved differently according to air temperature. Proglacial reaches were colder and less sensitive to air temperature in comparison with non-proglacial reaches. These findings allow for a prediction of habitat diversity from temperature heterogeneity based on time and the proportion of ponds, alluvial, and groundwater channels. 相似文献
109.
Experiments were performed, under transient conditions, to investigate the heat transfer phenomena of stationary hot steel plate under multiple top circular jets on run-out table. Based on inverse heat conduction model, a two-dimensional finite difference program was developed to calculate the local surface convective heat transfer coefficients and corresponding temperatures. The cooling water jet flow rate was varied from 15 L/min to 35 L/min and its effect on the convective heat transfer coefficient and surface temperature was analyzed. The results show that heat transfer coefficients are nonlinear functions of surface temperature. The cooling flow rate has no effect on heat transfer coefficient and surface temperature at stagnation point. Within 70 mm distance from stagnation line, heat transfer coefficient ratio changes slightly from 0.87 to 0.97. Beyond surface temperature of 350 °C, heat transfer coefficient ratio decreases with increasing distance from stagnation line. 相似文献
110.
C. Pi?eiro J. Barros-Velázquez Carmen G. Sotelo José M. Gallardo 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1999,11(12):342-348
The water-soluble proteins of nine flat fish species of high commercial value, belonging to the Pleuronectidae, Scophtalmidae, and Soleidae families, were analyzed by two-dimensional (2D) electrophoresis, this being carried out by nondenaturing isoelectric focusing (IEF) in the 3.5–9.5 pH range and gradient SDS-PAGE in the 12–14% range. Most of the major proteins fell in the 3.5–6.9 pH range. From these, the most specific proteins were in the acidic fraction (pI<5.2; MW<16 kDa). Species-specific 2D protein patterns were observed in all the nine species, and more than 25 proteins could be individualized. The combination of nondenaturing IEF and gradient SDS-PAGE, both in the absence of urea, allowed detailed characterization of both the isoelectric points and molecular weights of the major water-soluble proteins and proved to be a valuable tool for the differential characterization of the flat fish species studied. 相似文献