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121.
David Forrest 《The Cartographic journal》2013,50(3):213-214
In recent years, the concepts of usability, user experience, and user-centricity have gained in interest. Digital applications, developed in line with criteria related to these approaches, ask for a deeper understanding of users and their requirements. But, even though there is a wide range of methods available, the creation of user-centric applications with good usability and user experience still poses great challenges for developers. This is also true for web maps, i.e. web map applications, which today are ubiquitous on the Internet. They have evolved into an important information and communication tool and address users who do not possess any specific knowledge of Geoinformatics (GI) or Cartography. Despite the efforts made to meet the requirements and preferences of laymen, these users still often face problems when dealing with web map applications. This refers to aspects of design, content, and functionality. Here, participatory design, which is well-known in the field of Software and Web Engineering, might provide a suitable means. By engaging users directly and actively in the application development process, developers are able to gain a profound understanding of the users and their needs. However, there are several open questions regarding the use of participatory design for designing and implementing web map applications: What does the use of participatory design in web map development processes look like in detail? How and to what degree can users be involved in the development processes? Which added values exist? These questions are addressed by the project YouthMap 5020, whose main goal it was to create a prototype youth-centric web map for the Austrian city of Salzburg (zip code 5020). Applying the approach of participatory design, about 120 teenage pupils from several local schools were involved in all kinds of tasks related to the phases of generating the youth-centric Salzburg web city map. Experience and knowledge gained thereby allowed elaborating recommendations generally useful for generating youth-centric web map applications. 相似文献
122.
David P. Stevens 《地球物理与天体物理流体动力学》2013,107(1-4):103-133
Abstract An open boundary condition is constructed for three dimensional primitive equation ocean circulation models. The boundary condition utilises dominant balances in the governing equations to assist calculations of variables at the boundary. The boundary condition can be used in two forms. Firstly as a passive one in which there is no forcing at the boundary and phenomena generated within the domain of interest can propagate outwards without distorting the interior. Secondly as an active condition where a model is forced by the boundary condition. Three simple idealised tests are performed to verify the open boundary condition, (1) a passive condition to test the outflow of free Kelvin waves, (2) an active condition during the spin up phase of an ocean, (3) finally an example of the use of the condition in a tropical ocean. 相似文献
123.
Abstract Rough and smooth skates (Dipturus nasutus (Banks 1841) and/), innominatus (Garrick &; Paul 1974)) were aged by counting growth bands on X‐rays of thick sections of vertebral centra. Band counts were imprecise, but there was no between‐reader bias. Age estimates were not validated. The oldest rough skate was 9 years old, but few were more than 6 years old. Females may live longer than males. The combined sexes von Bertalanffy growth curve was Lr = 91.3 (1 ‐ e?0.16[t + 1.20]). Half the males matured by c. 52 cm pelvic length (PL) and 4 years, and females by 59 cm PL and 6 years. The oldest smooth skate in the sample was 24 years, but longevity probably exceeds that. Females appear to live longer than males. The combined sexes von Bertalanffy growth curve was: Lt = 150.5 (1 ‐ e?0.095[t + 1.06]). Half the males matured by c. 93 cm PL and 8 years, and females by 112 cm PL and 13 years. Smooth skate are late maturing and long‐lived relative to other skates, whereas rough skate are early maturing with a moderate life span. 相似文献
124.
Murray J. Smith Craig L. Stevens Richard M. Gorman John A. McGregor Cameron G. Neilson 《新西兰海洋与淡水研究杂志》2013,47(5):985-1000
Locally generated wind‐waves in estuaries play an important role in the sediment dynamics and the transport of biota. Wave growth in estuaries is complicated by tidally varying depth, fetch, and currents. Wave development was studied at six sites along a transect across Manukau Harbour, New Zealand, which is a large intertidal estuary with a tidal range of up to 4 m. Three meteorological masts were also deployed across the measurement transect to measure wave forcing by the wind. A spatial variation in wind speed by up to a factor of 2 was observed which has a significant effect on wave development at short fetches. The wind variation can be explained by the extreme change in surface roughness at the upwind land‐water boundary. The tidally varying depth results in non‐stationary wave development. At the long fetch sites wave development is dictated by the tidally varying depth with peak frequencies continuing to decrease after high water, whereas wave height is attenuated by bottom friction. The non‐dimensional energy and peak frequency parameters commonly used to describe wave growth, clearly exhibit depth limiting effects, but with wider scatter than in previous studies in simpler environments. The peak frequency predictions of Young & Verhagen (1996a) fit our data well. However, the wide variability of energy limits the usefulness of standard growth prediction curves in such situations, and highlights the requirement for a validated, shallow‐water numerical model. 相似文献
125.
Mark E. Hervig Larry L. Gordley Michael H. Stevens James M. Russell Scott M. Bailey Gerd Baumgarten 《Journal of Atmospheric and Solar》2009,71(3-4):316-330
The Solar Occultation For Ice Experiment (SOFIE) was launched onboard the Aeronomy of Ice in the Mesosphere (AIM) spacecraft to measure polar mesospheric clouds (PMCs) and their environment. This work describes methods for identifying PMCs in SOFIE observations and determining mass density, particle shape, particle effective radius, and the parameters of a Gaussian size distribution. Results using SOFIE measurements from the northern summer of 2007 are compared with concurrent observations by the ALOMAR lidar in northern Norway. Ice particle properties determined from SOFIE are in good agreement with the lidar results, considering the differences in instrument characteristics. 相似文献
126.
Michael H. Stevens Christoph R. Englert Mark Hervig Svetlana V. Petelina Werner Singer Kim Nielsen 《Journal of Atmospheric and Solar》2009,71(3-4):401-407
We present the first measurement of polar mesospheric cloud (PMC) occurrence frequency over the diurnal cycle from a satellite. The observations are made during the 2007 northern hemisphere PMC season by the Spatial Heterodyne IMager for MEsospheric Radicals (SHIMMER), which views the limb near 309 nm typically between 34 and 98 km. The PMC diurnal variation is derived between 50 and 58°N, where local times at the tangent point precess by ~30 min/day allowing for observations between 0330 and 2130 local time during the PMC season. We find that the occurrence frequencies exhibit a strong semidiurnal behavior with peaks near 0600 and 1800 local time and a minimum between 0900 and 1600 during which they are on average an order of magnitude less. The semidiurnal dependence is strongly correlated with concurrent ground-based measurements of meridional winds and temperatures measured at the same latitude. Our results for PMC frequency over the diurnal cycle can be used to help reconcile observations from other satellites that only permit cloud measurements at discrete local times. 相似文献
127.
High-altitude data assimilation system experiments for the northern summer mesosphere season of 2007 总被引:1,自引:0,他引:1
Stephen D. Eckermann Karl W. Hoppel Lawrence Coy John P. McCormack David E. Siskind Kim Nielsen Andrew Kochenash Michael H. Stevens Christoph R. Englert Werner Singer Mark Hervig 《Journal of Atmospheric and Solar》2009,71(3-4):531-551
A global numerical weather prediction system is extended to the mesosphere and lower thermosphere (MLT) and used to assimilate high-altitude satellite measurements of temperature, water vapor and ozone from MLS and SABER during May–July 2007. Assimilated temperature and humidity from 100 to 0.001 hPa show minimal biases compared to satellite data and existing analysis fields. Saturation ratios derived diagnostically from these assimilated temperature and water vapor fields at PMC altitudes and latitudes compare well with seasonal variations in PMC frequency measured from the aeronomy of ice in the mesosphere (AIM) satellite. Synoptic maps of these diagnostic saturation ratios correlate geographically with three independent transient mesospheric cloud events observed at midlatitudes by SHIMMER on STPSat-1 and by ground observers during June 2007. Assimilated temperatures and winds reveal broadly realistic amplitudes of the quasi 5-day wave and migrating tides as a function of latitude and height. For example, analyzed winds capture the dominant semidiurnal MLT wind patterns at 55°N in June 2007 measured independently by a meteor radar. The 5-day wave and migrating diurnal tide also modulate water vapor mixing ratios in the polar summer MLT. Possible origins of this variability are discussed. 相似文献
128.
Lagrangian drifters, moored acoustic Doppler current meters and hydrographic observations are combined with wind observations to describe the mean and variable nature of flow around Kapiti Island, New Zealand. Thirteen day-long deployments of up to six Lagrangian drifters show the mean flow is to the southwest, with evidence of stronger flows in the channel separating the island from the mainland, and an island wake in the lee of the island. Vortices in this island wake may be tidally driven. Scaling considerations suggest the flow is strong enough that tidal-generated vortices are shed on each tidal cycle. Both the drifters and mooring data suggest that the d’Urville Current around Kapiti Island has a significant wind-driven component. During north-westerlies, the drifters tend to hug the coast, and south-eastwards flows in the Rauoterangi Channel are accelerated. We suggest the observed correlation is the local expression of a South Taranaki basin scale response to the winds. 相似文献
129.
The trace element compositions of S-type granites: evidence for disequilibrium melting and accessory phase entrainment in the source 总被引:4,自引:2,他引:2
Arnaud Villaros Gary Stevens Jean-François Moyen Ian S. Buick 《Contributions to Mineralogy and Petrology》2009,158(4):543-561
Within individual plutons, the trace element concentrations in S-type granites generally increase with maficity (total iron
and magnesium content and expressed as atomic Fe + Mg in this study); the degree of variability in trace element concentration
also expands markedly with the same parameter. The strongly peraluminous, high-level S-type granites of the Peninsular Pluton
(Cape Granite Suite, South Africa) are the product of biotite incongruent melting of a metasedimentary source near the base
of the crust. Leucogranites within the suite represent close to pure melts from the anatectic source and more mafic varieties
represent mixtures of melt and peritectic garnet and ilmenite. Trace elements such as Rb, Ba, Sr and Eu, that are concentrated
in reactant minerals in the melting process, show considerable scatter within the granites. This is interpreted to reflect
compositional variation in the source. In contrast, elements such as LREE, Zr and Hf, which are concentrated within refractory
accessory phases (zircon and monazite), show well-defined negative correlations with increasing SiO2 and increase linearly with increasing maficity. This is interpreted to reflect coupled co-entrainment of accessory minerals
and peritectic phases to the melt: leucocratic rocks cannot have evolved from the more mafic compositions in the suite by
a process of fractional crystallisation because in this case they would have inherited the zircon-saturated character of this
hypothetical earlier magma. Trace element behaviour of granites from the Peninsular Pluton has been modelled via both equilibrium
and disequilibrium trace element melting. In the disequilibrium case, melts are modelled as leaving the source with variable
proportions of entrained peritectic phases and accessory minerals, but before the melt has dissolved any accessory minerals.
Thus, the trace element signature of the melt is largely inherited from the reactants in the melting reaction, with no contribution
from zircon and monazite dissolution. In the equilibrium case, melt leaves the source with entrained crystals, after reaching
zircon and monazite saturation. A significant proportion of the rocks of the Peninsular Pluton have trace element concentrations
below those predicted by zircon and monazite saturation. In the case of the most leucocratic rocks all compositions are zircon
undersaturated; whilst the majority of the most mafic compositions are zircon oversaturated. However, in both cases, zircon
is commonly xenocrystic. Thus, the leucocratic rocks represent close to pure melts, which escaped their sources rapidly enough
that some very closely match the trace element disequilibrium melting model applied in this study. Zircon dissolution rates
allow the residency time for the melt in the source to be conservatively estimated at less than 500 years. 相似文献
130.
J. B. Stevens M. J. Coe D. A. H. Buckley 《Monthly notices of the Royal Astronomical Society》1999,309(2):421-429
The fields of eight X-ray sources in the Magellanic Clouds believed to be Be/X-ray binaries have been searched for possible Be-star counterparts. BVR c and H α CCD imaging was employed to identify early-type emission stars through colour indices and H α fluxes. Spectroscopy of five sources confirms the presence of H α emission in each case. Based on the positional coincidence of emission-line objects with the X-ray sources, we identify Be-star counterparts to the ROSAT sources RX J0032.9-7348, RX J0049.1-7250, RX J0054.9-7226 and RX J0101.0-7206, and to the recently discovered ASCA source AX J0051-722. We confirm the Be star nature of the counterpart to the HEAO1 source H0544-66. In the field of the ROSAT source RX J0051.8-7231 we find that there are three possible counterparts, each showing evidence for H α emission. We find a close double in the error circle of the EXOSAT source EXO 0531.1-6609, each component of which could be a Be star associated with the X-ray source. 相似文献