VirtualHome: Simulating Household Activities via Programs

In this paper, we are interested in modeling complex activities that occur in a typical household. We propose to use programs, i.e., sequences of atomic actions and interactions, as a high level representation of complex tasks. Programs are interesting because they provide a non-ambiguous representation of a task, and allow agents to execute them. However, nowadays, there is no database providing this type of information. Towards this goal, we first crowd-source programs for a variety of activities that happen in people's homes, via a game-like interface used for teaching kids how to code. Using the collected dataset, we show how we can learn to extract programs directly from natural language descriptions or from videos. We then implement the most common atomic (inter)actions in the Unity3D game engine, and use our programs to "drive" an artificial agent to execute tasks in a simulated household environment. Our VirtualHome simulator allows us to create a large activity video dataset with rich ground-truth, enabling training and testing of video understanding models. We further showcase examples of our agent performing tasks in our VirtualHome based on language descriptions.Comment: CVPR 2018 (Oral

Biofilm microbial community structure in an urban lake utilizing reclaimed water

Analyses of biofilm community structure may potentially be employed for aquatic ecosystem health assessment, however, to date, biofilm diversity within urban lakes using reclaimed water has not been examined. Accordingly, the microbial community diversity and structure of biofilms from the surface of multiple matrices with varying roughness (0.1, 1.0 and 10.0 μm) were characterized using a suite of molecular techniques including scanning electron microscopy, genetic fingerprinting and phospholipid-derived fatty acid analyses. Samples were largely comprised of inorganic particles, algae and numerous bacterial species; 12 phospholipid-derived fatty acid (PLFA) types were identified, significantly less than typically associated with sewage. Both growth matrix surface roughness and biofilm growth phase were shown to concur with significantly different microbial quantity and community structures. Gram-negative bacteria bacillus i15:03OH and 18:0 were the dominant bacterial genera, collectively comprising ≈75 % of identified PLFA species content. Calculated species diversity (H) and species dominance (D) exhibited identical correlational patterns with measured water quality parameters; significant positive correlations were exhibited with respect to Mg2, while significant negative correlations were found for NO3, TP, BOD, COD, SP, PO4, SO4 and pH. Results indicate that analyses of biofilm formation and structure could be effectively used to undertake integrated assessments of the ecological health of lake systems using reclaimed water. Further work is required to elucidate the optimum conditions for sample collection and analytical interpretation

Efikasnost korišćenja vode lubenice navodnjavane kapanjem u umerenim klimatskim uslovima

The objective of the study, conducted in Vojvodina a northern part of the Serbia Republic, was to analyse the effect of drip irrigation on yield, evapotranspiration and water productivity of watermelon (Cirullus lanatus Thunb.) grown with plasticulture. Irrigation was scheduled on the basis of water balance method. Daily evapotranspiration was computed using the reference evapotranspiration and crop coefficient. The yield of watermelon in irrigation conditions (37,28 t/ha) was significantly higher compared to non irrigated (9,98 t/ha). Water used on evapotranspiration in irrigation conditions was 398 mm and 117 mm on non-irrigated variant. The crop yield response factor of 1,04 for the whole growing season reveals that relative yield decrease was nearly equal to the rate of evapotranspiration deficit. The values of irrigation water use efficiency and evapotranspiration water use efficiency were 9,93 kg/m3 and 10,29 kg/m3 respectively. The determined results could be used as a good platform for watermelon growers in the region, in terms of improvement of the optimum utilization of irrigation water.Cilj istraživanja, sprovedenog u Vojvodini, bio je da se analizira efekat navodnjavanja kapanjem na prinos, evapotranspiraciju i produktivnost vode u usevu lubenice (Cirullus lanatus Thunb.), gajene na foliji. Vreme zalivanja je određeno na osnovu vodnog bilansa. Dnevne vrednosti evapotranspiracije su obračunate korišćenjem referentne evapotranspiracije i koeficijenta useva. Prinos lubenice u uslovima navodnjavanja (37,28 t/ha) bio je statistički značajno veći u odnosu na prinos u uslovima bez navodnjavanja (9,98 t/ha). Evapotranspiracija lubenice u uslovima navodnjavanja bila je 398 mm i 117 mm na nenavodnjavanoj varijanti. Obračunata vrednost koeficijenta opadanja prinosa od 1,04 za period vegetacije ukazuje da je relativno smanjenje prinosa bilo skoro jednako relativnom deficitu evapotranspiracije. Efikasnost korišćenja vode navodnjavanjem i evapotranspiracijom iznosila je 9,93 kg/m3 i 10,29 kg/m3, redom. Dobijeni rezultati mogu poslužiti kao dobra osnova za proizvođače lubenice u regionu, u smislu poboljšanja i optimizacije navodnjavanja

Measuring flow velocity on frozen and non-frozen slopes of black soil through leading edge method

Flow velocity is a major parameter related to hillslope hydrodynamics erosion. This study aims to measure flow velocity over frozen and non-frozen slopes through leading edge method before being calibrated with accurate flow velocity to determine the correct coefficient for convenience of flow velocity measurement. Laboratory experiments were conducted on frozen and non-frozen soil slopes with flumes involving four slope gradients of 5°, 10°, 15°, and 20°and three flow rates of 1, 2, and 4 L/min with a flume of 6 m long and 0.1 m wide. The measurements were made with a stopwatch to record the time duration that the water flow ran over the rill segments of 2, 4 and 6 m long. Accurate flow velocity was measured with electrolyte trace method, under pulse boundary condition. The leading edge and accurate flow velocities were used to determine the correction coefficient to convert the former to the latter. Results showed that the correction coefficient on frozen soil slope was 0.81 with a coefficient of determination (R2) of 0.99. The correction coefficient on non-frozen soil slope was 0.79 with R2 of 0.98. A coefficient of 0.8 was applicable to both soil surface conditions. The accurate velocities on the four frozen black soil slopes were approximately 30%, 54%, 71%, and 91% higher than those on non-frozen soil slopes. By contrast, the leading edge flow velocities on the frozen soil slopes were 23%, 54%, 67%, and 84% higher than those on non-frozen soil slopes. The flow velocities on frozen soil slopes increased with flow rate at all four slopes, but they increased from 5 to 15° before getting stabilized. Therefore, rill flow velocity can be effectively measured with leading edge method by multiplying the leading edge velocity with a correction coefficient of 0.80. This study provides a strategy to measure rill flow velocity for studies on soil erosion mechanisms

Investigation on thermal and thermomechanical performances of actively cooled corrugated sandwich structures

In order to prevent payload module from overheating or to be burnt up by large aerodynamic heating, a Thermal Protection System (TPS) with high performance is necessary to maintain normal work during flights. Actively cooled thermal protection systems become more and more popular with their advantages in flexible design, high cooling capability and reutilization. In the present research, an actively cooled thermal protection system with Corrugated Sandwich Structures is designed for use in hypersonic aircrafts. The heat transfer and fluid flow of typical corrugated sandwich structures of actively cooled thermal protection and bearing capability are analyzed and compared. The coupled thermomechanical analysis of the corrugated sandwich structures is performed in terms of the stress and displacement fields under different conditions. The investigation provides a powerful reference for further optimization design of thermal protection systems of hypersonic aircrafts