2,215 research outputs found
A New Insight into Land Use Classification Based on Aggregated Mobile Phone Data
Land use classification is essential for urban planning. Urban land use types
can be differentiated either by their physical characteristics (such as
reflectivity and texture) or social functions. Remote sensing techniques have
been recognized as a vital method for urban land use classification because of
their ability to capture the physical characteristics of land use. Although
significant progress has been achieved in remote sensing methods designed for
urban land use classification, most techniques focus on physical
characteristics, whereas knowledge of social functions is not adequately used.
Owing to the wide usage of mobile phones, the activities of residents, which
can be retrieved from the mobile phone data, can be determined in order to
indicate the social function of land use. This could bring about the
opportunity to derive land use information from mobile phone data. To verify
the application of this new data source to urban land use classification, we
first construct a time series of aggregated mobile phone data to characterize
land use types. This time series is composed of two aspects: the hourly
relative pattern, and the total call volume. A semi-supervised fuzzy c-means
clustering approach is then applied to infer the land use types. The method is
validated using mobile phone data collected in Singapore. Land use is
determined with a detection rate of 58.03%. An analysis of the land use
classification results shows that the accuracy decreases as the heterogeneity
of land use increases, and increases as the density of cell phone towers
increases.Comment: 35 pages, 7 figure
Three-Dimensional Reconstruction and Analysis of All-Solid Li-Ion Battery Electrode Using Synchrotron Transmission X-ray Microscopy Tomography
A synchrotron transmission X-ray microscopy tomography system with a spatial resolution of 58.2 nm at the Advanced Photon Source was employed to obtain three-dimensional morphological data of all-solid Li-ion battery electrodes. The three-phase electrode was fabricated from a 47:47:6 (wt %) mixture of Li(Ni1/3Mn1/3Co1/3)O2 as active material, Li1.3Ti1.7Al0.3(PO4)3 as Li-ion conductor, and Super-P carbon as electron conductor. The geometric analysis show that particle-based all-solid Li-ion battery has serious contact interface problem which significantly impact the Li-ion transport and intercalation reaction in the electrode, leading to low capacity, poor rate capability and cycle life
Magnetic phase transition in V2O3 nanocrystals
V2O3 nanocrystals can be synthesized through hydrothermal reduction of
VO(OH)2 using hydrazine as a reducing agent. Addition of different ligands to
the reaction produces nanoparticles, nanorods and nanoplatelets of different
sizes. Small nanoparticles synthesized in this manner show suppression of the
magnetic phase transition to lower temperatures. Using muon spin relaxation
spectroscopy and synchrotron x-ray diffraction, it is determined that the
volume fraction of the high-temperature phase, characterized by a rhombohedral
structure and paramagnetism, gradually declines with decreasing temperature, in
contrast to the sharp transition observed in bulk V2O3.Comment: 6 pages, 6 figure
Application of Local Fractional Series Expansion Method to Solve Klein-Gordon Equations on Cantor Sets
We use the local fractional series expansion method to solve the Klein-Gordon equations on Cantor sets within the local fractional derivatives. The analytical solutions within the nondifferential terms are discussed. The obtained results show the simplicity and efficiency of the present technique with application to the problems of the liner differential equations on Cantor sets
Результаты изучения палеодегазации неогена и перспективы нефтегазоносности Юго-Западного Крыма
Склад флюїдів з Гераклітiв принципово не відрізняється від складу газів із сучасних зон струминного виділення в Чорному морі, що є підтвердженням їх генетичного споріднення. Дані аналізів вказують на різкі коливання змістів і непостійний склад газових флюїдів палеодегазаціі в неогені. Наявність газів вуглеводнів та слідів нафти в Гераклітах, тектонічна будова регіону дозволяють зробити висновок про високі перспективи знаходження родовищ нафти і газу в Південно-Західному Криму.The composition of fluids from Heraclitus has no fundamental differences from the gas composition from the modern jet ejections zones in the Black Sea, which is a confirmation of their genetic relatedness. Data of analysis show sharp fluctuations of the contents and unstable structure of gas fluids paleo degassing of Neogene. The presence of hydrocarbon gases and traces of oil in Heraclitus, the tectonic structure of the region allow to conclude high prospects of finding oil and gas in the South-West Crimea
Economic evaluation of mobile phone text message interventions to improve adherence to HIV therapy in Kenya
A surge in mobile phone availability has fueled low cost short messaging service (SMS) adherence interventions. Multiple systematic reviews have concluded that some SMS-based interventions are effective at improving antiretroviral therapy (ART) adherence, and they are hypothesized to improve retention in care. The objective of this study was to evaluate the cost-effectiveness of SMS-based adherence interventions and explore the added value of retention benefits
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