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141.
Ann Vanclooster Nina Vanhaeren Pepijn Viaene Kristien Ooms Laure De Cock Veerle Fack 《International journal of geographical information science》2013,27(11):2284-2304
ABSTRACTPresent-day indoor navigation systems are often not well adapted to the specific needs and requirements of its users. This research aims at improving those indoor navigation systems by providing navigation support that cognitively closer to user preferences and behaviour. More specifically, the focus is on the implementation of an accurate turn calculation method in a turn minimization algorithm, aiming to lower the complexity of routes and route instructions. This new-introduced perception-based turn calculation procedure is based on a direct door-to-door walking pattern, and, in contrast to previous algorithms, independent of the underlying indoor network type. It takes into account the effects of geometry of indoor space on human movement. To evaluate its functioning, both the traditional algorithm and the proposed perception-based algorithm are applied in the fewest turns path algorithm. It is demonstrated that the proposed algorithm accurately calculates turns in alignment with people’s perception. The implementation of the calculation algorithm in the fewest turns path algorithm also allows future applications in indoor simplest path algorithms, and overall contributes to cognitively richer indoor navigation systems. 相似文献
142.
Thomas Meisel Nina Schöner Vaida Paliulionyte Elisabeth Kahr 《Geostandards and Geoanalytical Research》2002,26(1):53-61
Data are reported for rare earth elements (REE), Y, Th, Zr, Hf, Nb and Ta in four geological reference materials using sodium peroxide (Na2 O2 ) sintering and inductively coupled plasma-mass spectrometry. The described procedure was used by students during their thesis work. A compilation of their reference material data acquired over one year of laboratory work demonstrates the ease and reliability of the method and the high reproducibility of the analytical results. Relative standard deviations of up to thirty six measurements of one reference material were lower than 5% for Y and the REE. Reproduciblities of Zr, Hf, Nb, Ta and Th were higher at between 5% and 10%, and can be attributed to the inhomogeneous distribution of zircon and other trace mineral phases and uncorrected drift effects. The concentration data are compared to reference and literature values and demonstrate that the procedure is also accurate. New data on G-3 show some systematic deviations from G-2, which are statistically significant. 相似文献
143.
Nina N. Belcheva Maxim V. Zakhartsev Nadezhda V. Dovzhenko Avianna F. Zhukovskaya Victor Ya. Kavun Victor P. Chelomin 《Ocean Science Journal》2011,46(2):85-94
The digestive gland and gills of the mussel Crenomytilus grayanus extracted from three locations — (i) sampled from a clean and (ii) polluted site and (iii) transplanted from the nonpolluted
to polluted site - were analysed for antioxidant enzymes (superoxide dismutase, catalase, glutathione reductase), total oxyradical
scavenging capacity and levels of lipid peroxidation products (malondialdehyde, conjugated dienes and lipofuscin). Perturbation
of redox status was found in both digestive gland and gill tissues of mussels living in the polluted area. As the activities
of superoxide dismutase and catalase were 1.2–3 times higher, the total oxyradical scavenging capacity was lower by 20–35%
and the levels of lipid peroxidation products were 2–7 times higher compared to mussels from the reference site. In transplanted
mussels, the lipid peroxidation process in both tissues was significantly stimulated (the level of conjugated dienes was increased
1.7–2.5-fold; malondialdehyde and lipofuscin contents were increased 3.5–5-fold) and the total oxyradical scavenging capacity
fell by 50–70%. In addition, the transplantation generally resulted in transient and variable responses of antioxidant enzymes
for both tissues. Complex response-behaviour of the antioxidant enzymes strongly points to the necessity of employing a combined
approach that takes into account activities of antioxidant enzymes and the total oxyradical scavenging capacity, as well as
measurement of oxidative damage (e.g., lipid peroxidation) to evaluate the physiological health of molluscs. 相似文献
144.
Scale and resolution have long been key issues in geography. The rapid development of analytical cartography, GIS, and remote sensing (the mapping sciences) in the last decade has forced the issues of scale and resolution to be treated formally and better defined. This paper addresses the problem of scale and resolution in geographical studies, with special reference to the mapping sciences. The fractal concept is introduced, and its use in identifying the scale and resolution problem is discussed. The implications of the scale and resolution problem on studies of global change and modeling are also explored. 相似文献
145.
Mass migration to major USA cities is reworking patterns of ethnic jobholding and labor market segmentation. Employers in
a variety of industries have turned to recent migrants, many of whom are not authorized to work in the USA, as a stable labor
supply for low-wage jobs. As a result, many migrant workers enter urban economies through precarious jobs in low-wage industries
and the informal economy where they often endure routine violations of labor and employment laws. This paper examines the
activities of a “migrant worker center” in improving wages and working conditions in migrant labor markets. Through a case
study of a worker center located in a port-of-entry immigrant neighborhood on Chicago’s Southwest Side, we examine the geographies
of the low-wage labor market and the problems that have arisen for workers who hold jobs that effectively exist beyond the
reach of government regulation. We argue that migrant worker centers will likely emerge as a key resource for workers who
are drawn to global cities by the promise of economic opportunity yet confront harsh conditions in the local labor markets
in which they are employed. 相似文献
146.
Reference samples of rocks from the Institute of Geochemistry, Irkutsk (IGI) and the Research Institute of Applied Physics, Irkutsk University (RIAP) and silicate rocks from the GeoPT proficiency testing series were analysed with the aim of determining Ag, B, Ge, Mo, Sn, Tl and W abundances by an atomic-emission method with air-stabilized D.C. arc excitation. Many of the results reported are without recommended or assigned values. The results are compared with compilation data from the literature and, where possible, with assigned values for samples of the Geo PT series. 相似文献
147.
Ksenia Tlatova Andrey Tlatov Alexei Pevtsov Kalevi Mursula Valeria Vasil’eva Elina Heikkinen Luca Bertello Alexander Pevtsov Ilpo Virtanen Nina Karachik 《Solar physics》2018,293(8):118
We use recently digitized sunspot drawings from Mount Wilson Observatory to investigate the latitudinal dependence of tilt angles of active regions and its change with solar cycle. The drawings cover the period from 1917 to present and contain information as regards polarity and strength of magnetic field in sunspots. We identified clusters of sunspots of same polarity, and used these clusters to form “bipole pairs”. The orientation of these bipole pairs was used to measure their tilts. We find that the latitudinal profile of tilts does not monotonically increase with latitude as most previous studies assumed, but instead, it shows a clear maximum at about 25?–?30 degree latitudes. Functional dependence of tilt (\(\gamma\)) on latitude (\(\varphi\)) was found to be \(\gamma= (0.20\pm0.08) \sin(2.80 \varphi) + (-0.00\pm0.06)\). We also find that latitudinal dependence of tilts varies from one solar cycle to another, but larger tilts do not seem to result in stronger solar cycles. Finally, we find the presence of a systematic offset in tilt of active regions (non-zero tilts at the equator), with odd cycles exhibiting negative offset and even cycles showing the positive offset. 相似文献
148.
Stamatina Isari Nina Fragopoulu Stylianos Somarakis 《Estuarine, Coastal and Shelf Science》2008,79(4):607-619
Larval fish community structure was studied in the northeastern Aegean Sea (NEA) over an area influenced by the advection of Black Sea water (BSW). Sampling was carried out in early summer during a period of 4 years (2003–2006). Taxonomic composition and abundance presented high variability in space that remained relatively constant among years. Tow depth and indicators of trophic conditions in the upper water column (i.e., zooplankton displacement volume, fluorescence) explained significantly the structure of larval assemblages during all surveys. The northern continental shelf (Thracian and Strymonikos shelf), where a large amount of enriched, low salinity BSW is retained, was dominated by larvae of epipelagic species, mainly anchovy (Engraulis encrasicolus). Interannual changes in horizontal extension of the BSW seemed to match closely observed changes in the distribution of anchovy larvae. Mesopelagic fish larvae were particularly abundant beyond the continental shelf (over the North Aegean Trough) where a strong frontal structure is created between the low salinity waters of BSW origin and the high salinity waters of the Aegean Sea. Larvae of certain mesopelagic species (e.g., Ceratoscopelus maderensis) may occasionally be transported inshore when the prevailing current meanders towards the coast or feeds anticyclonic gyres over the continental shelf. 相似文献
150.