Search results for "observation"
showing 10 items of 1586 documents
THE EFFECT OF ALTERNATIVE PREY ON THE DYNAMICS OF IMPERFECT BATESIAN AND MÜLLERIAN MIMICRIES
2004
Both Batesian and Müllerian mimicries are considered classical evidence of natural selection where predation pressure has, at times, created a striking similarity between unrelated prey species. Batesian mimicry, in which palatable mimics resemble unpalatable aposematic species, is parasitic and only beneficial to the mimics. By contrast, in classical Müllerian mimicry the cost of predators' avoidance learning is shared between similar unpalatable co-mimics, and therefore mimicry benefits all parties. Recent studies using mathematical modeling have questioned the dynamics of Müllerian mimicry, suggesting that fitness benefits should be calculated in a way similar to Batesian mimicry; that i…
Statistical Learning for End-to-End Simulations
2018
End-to-end mission performance simulators (E2ES) are suitable tools to accelerate satellite mission development from concet to deployment. One core element of these E2ES is the generation of synthetic scenes that are observed by the various instruments of an Earth Observation mission. The generation of these scenes rely on Radiative Transfer Models (RTM) for the simulation of light interaction with the Earth surface and atmosphere. However, the execution of advanced RTMs is impractical due to their large computation burden. Classical interpolation and statistical emulation methods of pre-computed Look-Up Tables (LUT) are therefore common practice to generate synthetic scenes in a reasonable…
Toward a Collective Agenda on AI for Earth Science Data Analysis
2021
In the last years we have witnessed the fields of geosciences and remote sensing and artificial intelligence to become closer. Thanks to both the massive availability of observational data, improved simulations, and algorithmic advances, these disciplines have found common objectives and challenges to advance the modeling and understanding of the Earth system. Despite such great opportunities, we also observed a worrying tendency to remain in disciplinary comfort zones applying recent advances from artificial intelligence on well resolved remote sensing problems. Here we take a position on research directions where we think the interface between these fields will have the most impact and be…
Deep Gaussian processes for biogeophysical parameter retrieval and model inversion
2020
Parameter retrieval and model inversion are key problems in remote sensing and Earth observation. Currently, different approximations exist: a direct, yet costly, inversion of radiative transfer models (RTMs); the statistical inversion with in situ data that often results in problems with extrapolation outside the study area; and the most widely adopted hybrid modeling by which statistical models, mostly nonlinear and non-parametric machine learning algorithms, are applied to invert RTM simulations. We will focus on the latter. Among the different existing algorithms, in the last decade kernel based methods, and Gaussian Processes (GPs) in particular, have provided useful and informative so…
Synergistic integration of optical and microwave satellite data for crop yield estimation
2019
Developing accurate models of crop stress, phenology and productivity is of paramount importance, given the increasing need of food. Earth observation (EO) remote sensing data provides a unique source of information to monitor crops in a temporally resolved and spatially explicit way. In this study, we propose the combination of multisensor (optical and microwave) remote sensing data for crop yield estimation and forecasting using two novel approaches. We first propose the lag between Enhanced Vegetation Index (EVI) derived from MODIS and Vegetation Optical Depth (VOD) derived from SMAP as a new joint metric combining the information from the two satellite sensors in a unique feature or des…
Phase error analysis of clipped waveforms in surface topography measurement using projected fringes
2021
Abstract When working with the method of projected fringes outside the optical laboratory one often encounters the problem of uncontrollable ambient light. This might cause saturation of the camera which in turn results in clipping of the fringes. Since standard theories describing phase-shifting techniques assume the projected fringes to be purely sinusoidal, such clipping will result in measurement error. In this paper a detailed analysis of this problem is given, and relations between phase errors, the amount of fringe clipping and the number of phase steps are found. Moreover, the phase difference between the clipped and the unclipped fringes is described. This investigation is based on…
Quantifying residential PV feed-in power in low voltage grids based on satellite-derived irradiance data with application to power flow calculations
2016
AbstractA scheme using satellite-derived irradiance measurements to model the feed-in power of residential photovoltaic (PV) systems in a low voltage distribution grid is described. It is validated against smart meter measurements from a test site with 12 residential PV systems in the city of Ulm, Germany, during May 2013 to December 2014. The PV feed-in power is simulated in a 15-min time resolution based on irradiance data derived from Meteosat Second Generation satellite images by the physically based retrieval scheme Heliosat-4. The PV simulation is based on the nominal power and location of the PV systems as provided by the distribution system operator. Orientation angles are taken fro…
A cross-cultural study of behavioral inhibition in toddlers: East-West-North-South
2006
The prevalence of behavioral inhibition in toddlers was examined in five cultures. Participants in this study included 110 Australian, 108 Canadian, 151 Chinese, 104 Italian, and 113 South Korean toddlers and their mothers who were observed during a structured observational laboratory session. Matched procedures were used in each country, with children encountering an unfamiliar stranger with a truck and a robot. Indicators of inhibition included the length of time toddlers delayed before approaching the stranger and the duration of contact with their mother while the stranger was in the room. Results were generally consistent with expectations and showed differences between eastern and we…
From Togetherness to Equal Partnership in Role Play
1998
In the day care centre, already at the transition stage to role play children show different kinds of participation. They observe each other's play, share goal orientation and directly tutor each other. The play process is materially supported and often initiated by educators. However, children also need to acquire the power to act autonomously in role play. The different kinds of participation in young children's play, as well as the appearance and development of basic features of joint role play were examined in three games of a two‐year‐old girl, Katju, in her day care group. The games are examples of ten play sessions she was involved in. These data were collected by means of reactive p…
Teachers' contribution to the social life in Finnish preschool classrooms during structured learning sessions
2013
This study aimed to clarify and deepen the knowledge on and understanding of the role that teachers’ practices during teacher-led learning sessions play in creating and enhancing social life in Finnish preschool classrooms. Observational data pertaining to 20 preschool teachers were analysed according to the principles of thematic analysis. Four identified themes reflected teachers’ contribution to social life in preschool classrooms in relation to their practices under different group compositions: (1) managing children’s peer-relations; (2) promoting the coherence of the group; (3) supporting individual child as a part of group; and (4) discussing friendship and respectfulness. As a concl…