695 research outputs found

    LAPR: An experimental aircraft pushbroom scanner

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    A three band Linear Array Pushbroom Radiometer (LAPR) was built and flown on an experimental basis by NASA at the Goddard Space Flight Center. The functional characteristics of the instrument and the methods used to preprocess the data, including radiometric correction, are described. The radiometric sensitivity of the instrument was tested and compared to that of the Thematic Mapper and the Multispectral Scanner. The radiometric correction procedure was evaluated quantitatively, using laboratory testing, and qualitatively, via visual examination of the LAPR test flight imagery. Although effective radiometric correction could not yet be demonstrated via laboratory testing, radiometric distortion did not preclude the visual interpretation or parallel piped classification of the test imagery

    Improving the accuracy of 1D SNMR surveys using the multi-central-loop configuration

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    Temeljna svrha i cilj ovoga rada bilo je ispitati koliko su potrošači skloni dijeljenju svojih turističkih iskustva s drugima te putem kojih medija. Osim navedenog, drugi cilj provedenog istraživanja bilo je utvrditi koliko su potrošačima važna iskustva i komentari drugih posjetitelja u procesu donošenja odluke o kupnji. Istraživanje je provedeno metodom ispitivanja, a kao instrument korišten je anketni upitnik sastavljen od 22 pitanja. Utvrđivanjem problema istraživanja, postavljene su tri hipoteze. Od tri hipoteze, u potpunosti je dokazana samo prva koja pretpostavlja da su potrošačima tuđa iskustva i komentari od velike važnosti kod planiranja i odabira putovanja. Druga hipoteza je djelomično potvrđena, tj. potvrđeno je da su potrošači skloni dijeliti svoja iskustva s drugima u situaciji kada su jako zadovoljni dok s druge strane nije potvrđeno kako su potrošači skloni dijeliti svoja iskustva u situaciji kada su nezadovoljni uslugom ili proizvodom. Na kraju, potvrđena je i treća hipoteza koja pretpostavlja kako su potrošači skloni dijeljenju vlastitog turističkog iskustva putem više društvenih medija, iako je utvrđeno kako najveći broj ispitanika ne dijeli svoja turistička iskustva. Istraživano je i mišljenje ispitanika o turističkoj destinaciji iz snova, a iznenađujuće, najveći broj ispitanika je navelo hrvatske destinacije kao svoje destinacije iz snova kao i one koje su im dosada pružile najnezaboravnije turističko iskustvo. Potrebno je provesti detaljnija istraživanja kako bi se detaljnije istražilo novije društvene medije koji su dostupni potrošačima za dijeljenje svog iskustva

    Improving the accuracy of 1D SNMR surveys using the multi-central-loop configuration

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    A multi-central loop configuration has been studied through forward and inverse modelling of synthetics and real data. This set-up takes advantage of the multichannel features of the NMR device and consists of using several (2 to 3) additional receiver loops displayed concentrically with the main transmitter/receiver loop, which all record the NMR signal simultaneously within a single acquisition. If the loop diameters are chosen appropriately, the kernel sensitivity distributions for each receiver loop can show complementary features. Inverting simultaneously the data sets obtained through each different receiver loop can then enhance the accuracy of the final model. To do so, a 1D QT inversion scheme in the frequency domain dedicated to the inversion of multiple data sets is being used. One challenging feature is to adapt the regularization of the inverse process so as to handle correctly the noise originating from different data sets. The efficiency of this multi-central loop acquisition set-up and procedure is being assessed through the forward and inverse modelling of several scenarios implying varying aquifer characteristics. Finally a field case is being presented that was conducted on a low noise level site located in Germany, where conditions were favourable to the implementation and testing of circular multi-central loop configurations.We also introduce a new method for determining NMR parameters, named the prediction-focused-approach (PFA), that is based on statistical analysis of a large number of simple models. We observe, using synthetic examples, that the effciency of the method benefits from the use of the multi-central-loop configurations

    Advanced Solidstate Array Spectroradiometer

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    During the Summer of 1987, the Advanced Solidstate Array Spectroradiometer (ASAS) was installed and flown on the NASA Ames C-130 in support of the First International Field Experiment (FIFE) missions. The study site was over the grassland areas of the Konza Prairie in Kansas. The data collected with ASAS during these flights has been used to produce the first nearly simultaneous multiangular/multispectral images of selected terrestrial study sites. This data will be valuable in the study of surface bidirectional reflectance and albedo. The data will also be useful for the development of data analysis algorithms for future spaceborne instruments such as the Goddard MODIS-T and JPL's HIRIS. The flight data acquired is further analyzed

    Self-compassion and compassion towards one’s partner mediate the negative association between insecure attachment and relationship quality.

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    The quality of intimate relationships has been found to be a strong negative predictor for individuals’ mental and physical health problems. A significant predictor of relationship quality is adult attachment insecurity, but the mechanism by which attachment insecurity affects relationship quality needs further investigation. This study investigated whether self-compassion and compassion for one’s partner mediated this association. Three-hundred-forty-two individuals participated in an online survey assessing attachment anxiety and avoidance, compassionate and uncompassionate attitude towards self and one’s partner, as well as relationship quality and relationship satisfaction. The results showed that low self-compassionate attitude mediated the association between attachment anxiety and poor relationship quality. Further, low compassionate and high uncompassionate attitude towards one’s partner mediated the association between attachment avoidance and poor relationship quality. No mediating effect was found for relationship satisfaction. Implications for interventions are discussed

    Advanced Solid-State Array Spectrometer (ASAS) data sets from the 1990 field season: A unique look at two forested ecosystems

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    The Advanced Solid-state Array Spectrometer (ASAS) is a pointable imaging spectrometer which uses a solid-state array to acquire imagery of terrestrial targets in 29 spectral bands from .4 to .8 microns. Performance and calibration of the instrument are described. The ASAS data sets obtained in 1990 provide a unique look at forest canopies from two different forest regions of the North America continent under varying temporal, spectral, and bidirectional conditions. These data sets will be used to study such parameters as the albedo of forest canopies, the dynamics of scene radiation due to factors such as canopy architecture, moisture stress, leaf chemistry, topography, and understory composition

    Electromagnetic Pulse Sounding for Surveying Underground Water

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    This project supported in part by the Office of Water Resources Research U. S. Department of the Interior Washington, D. C. under Project B-028-OHIOA number of approaches have been explored for measuring the water content of soil electrically. In contrast with traditional measurements, which utilize electric currents at DC or at specific frequencies, our techniques have been based on the transmission and reflection of sharp, regularly repeated pulses. Such pulse measurements can be shown to be equivalent to measuring the electrical properties at all frequencies in a very wide band, and therefore the possibility of extracting the desired information is much greater than with single-frequency measurements. Because the information content of the signal is great, data processing can be used to extract those features which relate most directly to moisture content and reject those which appear to depend more on soil inhomogenieties. For example, it was found that the attenuation in the frequency band of approximately 10 to 20 MHz had a much higher correlation with soil moisture than that in other frequency bands for the actual field conditions under which our measurements were made. This information content increase is obtained by means of sophisticated research equipment. The measurements reported herein were made and processed under real-time computer control. They include the signal scattered from known buried targets, transmission measurements through the ground, and the measurement of reflections in a coaxial test cell, all with pulses containing very wide frequency bands. The results are encouraging in that definite correlations with moisture were found. Unfortunately the one-year time limitation of this effort, much of it spent in instrumentation development, was insufficient to allow testing these correlations quantitatively over extended time periods or in a variety of locations. Thus the techniques must be evaluated at present as promising, but not fully proven. It should be noted that, while the research system to obtain this information is complex, field equipment based on these techniques need not be unduly complicated or expensive. Once the features relating to moisture content under the greatest variety of field conditions are identified, means for extracting this information more simply should be devised. This is proposed as the objective for continuation of this effort.Summary -- Introduction -- 1. The Measuring System -- 2. Data Processing -- 3. Underground Moisture Content Monitoring by Measurement of Buried Target Signatures -- 4. Sampled Moisture Conditions -- 5. Underground Propagation Experiment -- 6. Reflection Measurements on Soil Samples in a Vertical Coaxial Test Cell -- 7. Propagation Calculations -- Conclusions -- Recommendations -- References -- Appendix I - Transmission Measurements using a Buried Antenn

    The diurnal cycle of shallow cumulus clouds over land: A single-column model intercomparison study

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    An intercomparison study for single-column models (SCMs) of the diurnal cycle of shallow cumulus convection is reported. The case, based on measurements at the Atmospheric Radiation Measurement program Southern Great Plains site on 21 June 1997, has been used in a large-eddy simulation intercomparison study before. Results of the SCMs reveal the following general deficiencies: too large values of cloud cover and Cloud liquid water, unrealistic thermodynamic profiles, and high amounts of numerical noise. Results are also strongly dependent on vertical resolution.These results are analysed in terms of the behaviour of the different parametrization schemes involved: the convection scheme, the turbulence scheme, and the cloud scheme. In general the behaviour of the SCMs can be grouped in two different classes: one class with too strong mixing by the turbulence scheme, the other class with too strong activity by the convection scheme. The coupling between (subcloud) turbulence and the convection scheme plays a crucial role. Finally, (in part) motivated by these results several models have been successfully updated with new parametrization schemes and/or their present schemes have been successfully modifie
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