Content-dependency reduction with multi-task learning in blind stitched panoramic image quality assessment

In this work, we investigate deep learning based solutions to blind quality assessment of stitched panoramic images (SPI). The main problem to tackle is that the ground truth data is usually insufficient. As a result, the learned model can easily overfit data with specific content. Because most distortions of SPIs lie within local regions, the problem cannot be alleviated by commonly-used patch-wise training, which assumes local quality equals global quality. We propose a multi-task learning strategy which encourages learned representation to be less dependent on image content. A siamese network with two weight-shared CNN branches is trained to simultaneously compare the quality of two images of the same scene and predict the quality score of each image. Since two images of the same scene are processed by the same CNN, the CNN tends to find their quality differences instead of content differences under the constraint of the quality ranking objective. Because two tasks share the same representations learned by the CNN, the regression task can be further benefited from the quality-sensitive representations. Extensive experiments demonstrate the effectiveness of the proposed model and its superiority over existing SPI quality assessment methods.Accepted versio

Surface modification of calcium carbonate nanoparticles as hydraulic oil additives friction performance research

In this experiment, calcium carbonate nanopartilces were prepared by metathesis method. The calcium carbonate powders were modified by sodium dodecyl sulfonate. The characteristics of raw and modified calcium carbonate powders were analyzed and characterized by various methods. The size of the unmodified nano-calcium carbonate is about 2.7 μm, and the particle size of the modified particles is about several hundred nanometers. The CFT-1 material performance tester was utilized to evaluate the tribological characteristics of the additive. The data show that the modified nano-calcium carbonate can improve the anti-friction and anti-friction performance of hydraulic oil

Home Range and Habitat Disturbance Identification for a Vulnerable Shorebird Species (Larus saundersi) in the Yellow River Delta, China

Understanding the home range of animal species can be helpful to biodiversity and habitat conservation. Saunders's Gull (Lams saundersi), one of the vulnerable birds in the world, has become an important indicator species to measure the quality of ecological environment in the coastal wetlands of the Yellow River Delta. Information about habitat selection of the species has so far been mainly from field survey. In view of the successful application of satellite tracking in animal ecology, two individual birds were tagged for home range identification and habitat disturbance analysis. The gull's home range was confirmed using the Brownian bridge movement model. Habitat disturbances information from anthropogenic activities was analyzed by kernel density estimation as well as buffer zone analysis. Considering the gregariousness of the shorebird, the tracking sample data, though limited, can reflect the species' habitat selection to a certain extent. The results showed that (1) the Saunders's Gull's main home range was located in the northern and eastern coastal areas of Dongying city, the seashore area at the border of Binzhou with Dongying and Cangzhou city, and the Nanpu wetland of Tangshan city; and (2) human activity had a substantial effect on the home range selection, for example, mariculture was an important part of its home range, the Saunders's Gull exhibited an approach-avoidance behavior to wind turbines and oil wells, and activity time varied with different distances to the road. The study provides insights into the behavior of the shorebird and is of great significance to sustainable development of the human-environment relationship in the Yellow River Delta

Analysis of the Formation Mechanism of Medium and Low-Temperature Geothermal Water in Wuhan Based on Hydrochemical Characteristics

Wuhan and its surrounding areas have obvious geothermal spring outcrops, which are unexplored potential geothermal resources. The degree of geothermal resource development in Wuhan is low, and there is a lack of systematic research on their hydrochemical characteristics and formation mechanism. The Wuhan area is bounded by the Xiang-Guang fault, the South Qinling-Dabie orogenic belt in the north, and the Yangtze landmass in the south, with Silurian and Quaternary outcrops and little bedrock outcrops. The Silurian is the main water barrier in the region, which separates the upper Triassic and Paleogene as shallow aquifers and the lower Cambrian and Ordovician as deep aquifers. Different strata are connected by a series of fault structures, which constitute Wuhan’s unique groundwater water-bearing system. Eleven geothermal water (23~52 °C) and six surface water samples (around 22 °C) were collected from the study area. The geothermal water in the study area is weakly alkaline, with a pH of 7.04~8.24. The chemical type of geothermal water is mainly deep SO42− with a higher TDS and shallow HCO3− type water with a lower TDS. Isotopic analysis indicates that atmospheric precipitation and water-rock interaction are the main ionic sources of geothermal water. The chemical composition of geothermal water is dominated by ion-exchange interactions and the dissolution of carbonates and silicates. The characteristic coefficients, correlation analysis, water chemistry type, recharge elevation, geothermal water age, reservoir temperature, and cycle depth were also analyzed. The performance was similar in the same geothermal reservoir, which could be judged as an obviously deep and shallow geothermal fluid reservoir, and the genetic conceptual model of Wuhan geothermal was preliminarily deduced. DXR-8 and DXR-9 had the best reservoir conditions, hydrodynamic conditions, rapid alternation of water bodies, and large circulation depth, which is a favorable location for geothermal resource development and will bring considerable economic and social benefits

Genesis of Geothermal Waters in Suichuan County, China: An Integrated Method Constrained by the Hydrochemical and Isotopic Characteristics

Numerous geothermal resources of medium to low temperature have been reported in southern China. Suichuan County is one of the regions where thermal manifestations are abundant. However, the study regarding the understanding of geothermal water sources, hydrochemical composition and fluid-rock interaction lacks behind. Therefore, this study has characterized the slightly acidic to slightly alkaline bicarbonate geothermal waters of medium-low temperature of the Suichuan area. Geothermal waters of the study area have been evaluated mainly as of HCO3-Ca-Na hydrochemical type with a maximum temperature of 80 °C. The results indicate the low hydrochemical concentration where HCO3− acts as a principal anion. Furthermore, the F− content in geothermal and two cold water samples have been found high with a maximum value of 13.4 (mg/L), showing high pH of 9.6 as well. Here, the compilation of deuterium and oxygen-18 isotopic data of geothermal waters showed a local precipitation origin with a recharge elevation ranging from 630–1000 m. The circulation depth and reservoir temperatures are estimated, explaining the deep thermal water behavior. Additionally, the estimation of saturation indices of various minerals shows the geothermal waters’ corrosive or scaling behavior. Subsequently, the geothermal water points in the study area represent a fracture convection formation pattern. Finally, by integrating conventional hydrochemistry along with isotopic data, and considering the geological framework, a conceptual genetic model of the Suichuan thermal ground waters has been discussed. Hydrochemistry and isotopic features along with a conceptual circulation model have been provided by the foundation towards the sustainable management of hydrothermal resources in Suichuan. Proper management policies and practices are required for further development of Suichuan hydrothermal waters