1,697 research outputs found
TIME-RELATED QUALITY DIMENSIONS OF URBAN REMOTELY SENSED BIG DATA
Abstract. Our rapidly changing world requires new sources of image based information. The quickly changing urban areas, the maintenance and management of smart cities cannot only rely on traditional techniques based on remotely sensed data, but also new and progressive techniques must be involved. Among these technologies the volunteer based solutions are getting higher importance, like crowd-sourced image evaluations, mapping by satellite based positioning techniques or even observations done by unskilled people. Location based intelligence has become an everyday practice of our life. It is quite enough to mention the weather forecast and traffic monitoring applications, where everybody can act as an observer and acquired data â despite their heterogeneity in quality â provide great value. Such value intuitively increases when data are of better quality. In the age of visualization, real-time imaging, big data and crowd-sourced spatial data have revolutionary transformed our general applications. Most important factors of location based decisions are the time-related quality parameters of the used data. In this paper several time-related data quality dimensions and terms are defined. The paper analyses the time sensitive data characteristics of image-based crowd-sourced big data, presents quality challenges and perspectives of the users. The data quality analyses focus not only on the dimensions, but are also extended to quality related elements, metrics. The paper discusses the connection of data acquisition and processing techniques, considering even the big data aspects. The paper contains not only theoretical sections, strong practice-oriented examples on detecting quality problems are also covered. Some illustrative examples are the OpenStreetMap (OSM), where the development of urbanization and the increasing process of involving volunteers can be studied. This framework is continuing the previous activities of the Remote Sensing Data Quality Working Group (ICWGIII/IVb) of the ISPRS in the topic focusing on the temporal variety of our urban environment.</p
Lattice sites of ion-implanted Li in diamond
Published in: Appl. Phys. Lett. 66 (1995) 2733-2735
citations recorded in [Science Citation Index]
Abstract: Radioactive Li ions were implanted into natural IIa diamonds at temperatures between 100 K and 900 K. Emission channelling patterns of a-particles emitted in the nuclear decay of 8Li (t1/2 = 838 ms) were measured and, from a comparison with calculated emission channelling and blocking effects from Monte Carlo simulations, the lattice sites taken up by the Li ions were quantitatively determined. A fraction of 40(5)% of the implanted Li ions were found to be located on tetrahedral interstitial lattice sites, and 17(5)% on substitutional sites. The fractions of implanted Li on the two lattice sites showed no change with temperature, indicating that Li diffusion does not take place within the time window of our measurements.
Emission patterns of neutral pions in 40 A MeV Ta+Au reactions
Differential cross sections of neutral pions emitted in 181Ta + 197Au
collisions at a beam energy of 39.5A MeV have been measured with the photon
spectrometer TAPS. The kinetic energy and transverse momentum spectra of
neutral pions cannot be properly described in the framework of the thermal
model, nor when the reabsorption of pions is accounted for in a
phenomenological model. However, high energy and high momentum tails of the
pion spectra can be well fitted through thermal distributions with unexpectedly
soft temperature parameters below 10 MeV.Comment: 16 pages (double-spaced), 5 figures; corrections after referee's
comments and suggestion
Geometric phase effects for wavepacket revivals
The study of wavepacket revivals is extended to the case of Hamiltonians
which are made time-dependent through the adiabatic cycling of some parameters.
It is shown that the quantal geometric phase (Berry's phase) causes the revived
packet to be displaced along the classical trajectory, by an amount equal to
the classical geometric phase (Hannay's angle), in one degree of freedom. A
physical example illustrating this effect in three degrees of freedom is
mentioned.Comment: Revtex, 11 pages, no figures
Thermal bremsstrahlung probing the thermodynamical state of multifragmenting systems
Inclusive and exclusive hard-photon (E 30 MeV) production in five
different heavy-ion reactions (Ar+Au, Ag, Ni,
C at 60{\it A} MeV and Xe+Sn at 50{\it A} MeV) has been
studied coupling the TAPS photon spectrometer with several charged-particle
multidetectors covering more than 80% of 4. The measured spectra, slope
parameters and source velocities as well as their target-dependence, confirm
the existence of thermal bremsstrahlung emission from secondary nucleon-nucleon
collisions that accounts for roughly 20% of the total hard-photon yield. The
thermal slopes are a direct measure of the temperature of the excited nuclear
systems produced during the reaction.Comment: 4 pages, 3 figures, Proceedings CRIS 2000, 3rd Catania Relativistic
Ion Studies, "Phase Transitions in Strong Interactions: Status and
Perspectives", Acicastello, Italy, May 22-26, 2000 (to be published in Nuc.
Phys. A
OdreÄivanje aktivacijske energije za proraÄun pri toploj preradi svojstava metala
The hot workability of metals is most commonly described by the hyperbolic-sine constitutive equation, which relates stress with strain rate and temperature. In the present paper a simple method for calculating the parameters of this equation is introduced. Hot compression experiments of an AA6082 aluminium alloy were carried out to check the reliability of the proposed method. Based on analysis of the experimental results, a simple semi-empirical equation to describe the flow stress as a function of strain, strain rate and temperature was formulated. A good agreement between the predicted and the experimental data was achieved.PreraÄivaÄka svojstva metala u toplom stanju obiÄno opisuju sa hiperboliÄko-sinusnim jednadĆŸbama, gdje je naprezanje funkcija brzine deformacije i temperature. U Älanku je predloĆŸena jednostavna metoda za izraÄunavanje tih parametara. Metoda je provjerena na temelju tlaÄne probe tople deformacije aluminijske slitine AA6082. Na osnovu analize eksperimentalnih rezultata bila je formulirana jednostavna polu-empirijska ovisnost za opis naprezanja teÄenja kao funkcije deformacije, brzine deformacije i temperature. Analiza iskazuje dobru skladnost izmeÄu eksperi-mentalnih i prognoziranih vrijednosti
Kaon Condensation in the Bound-State Approach to the Skyrme Model
We explore kaon condensation using the bound-state approach to the Skyrme
model on a 3-sphere. The condensation occurs when the energy required to
produce a falls below the electron fermi level. This happens at the
baryon number density on the order of 3--4 times nuclear density.Comment: LaTeX format, 15 pages. 3 Postscript figures, compressed and
uuencode
The CERN laser-ion source
This paper describes the first results of a feasibility study undertaken at CERN to determine whether a laser-produced plasma can be used as a source of intense highly charged heavy ion beams. A variety of important measurements have been made, and the results are encouraging. Furthermore, a beam of highly charged light ions produced by the laser ion source has been accelerated successfully in a radio frequency quadrupole (RFQ) structur
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