AdaptivePose++: A Powerful Single-Stage Network for Multi-Person Pose Regression

Multi-person pose estimation generally follows top-down and bottom-up paradigms. Both of them use an extra stage ($\boldsymbol{e.g.,}$ human detection in top-down paradigm or grouping process in bottom-up paradigm) to build the relationship between the human instance and corresponding keypoints, thus leading to the high computation cost and redundant two-stage pipeline. To address the above issue, we propose to represent the human parts as adaptive points and introduce a fine-grained body representation method. The novel body representation is able to sufficiently encode the diverse pose information and effectively model the relationship between the human instance and corresponding keypoints in a single-forward pass. With the proposed body representation, we further deliver a compact single-stage multi-person pose regression network, termed as AdaptivePose. During inference, our proposed network only needs a single-step decode operation to form the multi-person pose without complex post-processes and refinements. We employ AdaptivePose for both 2D/3D multi-person pose estimation tasks to verify the effectiveness of AdaptivePose. Without any bells and whistles, we achieve the most competitive performance on MS COCO and CrowdPose in terms of accuracy and speed. Furthermore, the outstanding performance on MuCo-3DHP and MuPoTS-3D further demonstrates the effectiveness and generalizability on 3D scenes. Code is available at https://github.com/buptxyb666/AdaptivePose.Comment: Submit to IEEE TCSVT; 11 pages. arXiv admin note: text overlap with arXiv:2112.1363

CeO2 Nanowires Inserted into Reduced Graphene Oxide as Active Electrocatalyst for Oxygen Reduction Reaction

Fabrication of an interconnected and conductive nano-architecture is a prospective strategy to design a high-performance and low cost electrocatalyst for oxygen reduction reaction (ORR). Herein, a novel nano-architecture assembled by graphene nanosheets and CeO2 nanowires (NWs) with a hierarchical structure was developed by a facile hydrothermal process using ethanol/water as solvents without any organic additives. In this framework, graphene oxide (GO) was reduced to graphene and chemical bonding formed between the GO and CeO2 NWs in a hydrothermal process. The imbedded CeO2 NWs could prevent the restacking of the graphene sheets and improved the electrical conductivity of the hybrid catalyst. The effect of different ratios of GO to CeO2 NWs in the hybrid were studied. The GO3-CeO2 NWs composite exhibited better catalytic performance with slow attenuation and high limiting current density 3.55 and 1.99 times higher than CeO2 NWs and pure GO. The onset potential of GO3-CeO2 NWs is 0.13 V and 0.05 V positive shift from that of CeO2 NWs and pure GO, respectively, suggesting that the GO3-CeO2 NWs hybrid had an excellent stability and activity for ORR. It was found that CeO2 NWs served not only as an effective catalyst but also as an “oxygen buffer” to relieve oxygen insufficiency for ORR

Nitrogen rather than streamflow regulates the growth of riparian trees

In arid and semiarid regions, riparian forests are crucial for maintaining ecological biodiversity and sustainability, and supporting social and economic development. For the typical arid and semiarid ecosystem, streamflow variability is thought to be the dominant factor influencing the vulnerability and evolution of the riparian forests, which often leads to the neglect of other potentially important factors such as nutrient availability and transport. Here, we measured annual stable nitrogen isotopes (δ15N) and nitrogen concentrations (N%) in the tree rings of Populus euphratica Oliv. (Euphrates poplar) over a 90 year period (1920–2012), collected from the lower researches of the inland Heihe River, northwestern China. Coupling with our previous dual-isotope (δ13C and δ18O) chronologies and estimated intrinsic water-use efficiency (iWUE), we examined the linkages between tree-ring δ15N and δ18O, iWUE, streamflow, and then explored the contributions of each to tree growth during the study period. Our results show that after 1975, a statistically significant correlation between tree-ring δ15N and river streamflow appears, indicating the river as a potential carrier of nitrogen from the upper and middle reaches to the lower research trees. In addition, the linkage between tree-ring δ15N and iWUE suggests substantial influence of carbon and nitrogen together on photosynthesis and transpiration of trees, although this connection become decoupled since AD 1986. The commonality analysis revealed that the nitrogen impacts indicated by tree-ring δ15N on tree growth cannot be ignored when evaluating riparian forest development. The fertilization effects caused by rising CO2 concentration complicate the nitrogen constraints on tree growth during the later part of the past century. Our results have potentially broad implications for identifying the limited factors for dryland forest ecosystems that are susceptible to natural water resource variations and human activities

The Relationship between Urbanization, Economic Growth and Energy Consumption in China: An Econometric Perspective Analysis

As the largest developing country in the world, with rapid economic growth, China has witnessed fast-paced urbanization development over the past three decades. In fact, urbanization has been shown to promote economic growth and improve the livelihood of people, but it can also increase energy consumption and further generate energy crisis. Therefore, a better understanding of the relationship between urbanization, economic growth and energy consumption is important for China’s future sustainable development. This paper empirically investigates the long-term equilibrium relationships, temporal dynamic relationships and causal relationships between urbanization, economic growth and energy consumption in China. Econometric models are utilized taking the period 1980–2012 into consideration. Cointegration tests indicate that the variables are found to be of I(1) and cointegrated. Further, vector error-correction model (VECM) indicates that when the short-term fluctuations deviate from the long-term equilibrium, the current changes of energy consumption could eliminate 9.74% non-equilibrium error of the last period, putting back the situation to the equilibrium state through a reverse adjustment. Impulse response analysis intuitively portrays the destabilized changes of the variables in response to some external shocks. However, the impact of energy consumption shock on urbanization and the impact of urbanization on economic growth seem to be rather marginal. Moreover, Granger causality results reveal that there is a bi-directional Granger causal relationship between energy consumption and economic growth, and unidirectional causality running from urbanization to energy consumption and economic growth to urbanization. The findings have important implications for Chinese policymakers that on the path towards a sustainable society, the effects of urbanization and economic growth on energy consumption must be taken into consideration

Micro-structural analysis on stress displacement and crack evolution of porous asphalt mixture based on DEM

The purpose of this study is to explore the micro-structure evolution and failure mechanism of porous asphalt mixture under stress. The micro-structural parameters of specimen section are imported into PFC2D, and the change of aggregate displacement is verified by discrete element modeling. Through digital image processing technology, a series of quantitative information of micro structure of mixture section is obtained, and these micro parameters are statistically analyzed, and the statistical results are compared with the macro test. Under the action of stress, porous asphalt mixture produces different degrees of strain. By comparing the meso structural parameters under different strains, the displacement of aggregate and the change process of voids are determined. The results show that with the increase of stress and strain, the specimen is gradually compacted, the aggregate displaces in different degrees, the cracks are gradually generated at the junction of aggregate and cracks, and the specimen is gradually destroyed. The change of void area, void number and void length width ratio can directly show the development process of fracture

Exploring the relationship between urbanization and the eco-environment - A case study of Beijing-Tianjin-Hebei region

China's high-speed economic growth has been characterized by rapid urbanization and a series of environmental issues. This study investigates the urbanization and eco-environment system from the perspective of interactive coercing theory and proposes a new comprehensive index system for the assessment of urbanization and the eco-environment. This is done using interactive coercing model (ICM) followed by a dynamic coupling coordination degree model (DCCDM) to estimate the relationship between urbanization and the eco-environment. This study focuses on the interactive coercing relationship, coupling coordination degree and coordinated patterns in the BTH (Beijing-Tianjin-Hebei) region, China, with panel data collected from 1980 to 2011. The main conclusions are as follows: (1) demographic urbanization and eco-environmental endowment make the greatest contribution to the compound system, indicating that they are the critical factors to consider when analyzing the interactive coercing relationship between urbanization and the eco-environment; (2) we find the double-exponential curve of urbanization and the eco-environment is in the form of an inverted-U curve, and thus the Kuznets hypothesis is confirmed by the empirical analysis; and (3) the dynamic of coordination of the selected cities shows an S-shaped curve and the corresponding state of the degrees evolves into the rudimentary symbiosis phase from the harmonious development phase during rapid urbanization, and it is revealed that the coordinated patterns of most sample cities are sensitive to the eco-environment, which indicates that the urban environment is subject to great pressure. The comprehensive indexes and the interactive coupling models may help the governments better understand the complex coupling relationship, and develop sustainable urbanization development strategies that better balance urbanization and eco-environmental protection. 2014 Elsevier Ltd

Estimation of Urban Housing Vacancy Based on Daytime Housing Exterior Images—A Case Study of Guangzhou in China

The traditional methods of estimating housing vacancies rarely use daytime housing exterior images to estimate housing vacancy rates (HVR). In view of this, this study proposed the idea and method of estimating urban housing vacancies based on daytime housing exterior images, taking Guangzhou, China as a case study. Considering residential quarters as the basic evaluation unit, the spatial pattern and its influencing factors were studied by using average nearest neighbor analysis, kernel density estimation, spatial autocorrelation analysis, and geodetector. The results show that: (1) The urban housing vacancy rate can be estimated by the method of daytime housing exterior images, which has the advantage of smaller research scale, simple and easy operation, short time consumption, and less difficulty in data acquisition. (2) Overall, the housing vacancy rate in Guangzhou is low in the core area and urban district, followed by suburban and higher in the outer suburb, showing a spatial pattern of increasing core area–urban district–suburban–outer suburb. Additionally, it has obvious spatial agglomeration characteristics, with low–low value clustered in the inner circle and high–high value clustered in the outer suburb. (3) The residential quarters with low vacancy rates (50%) are distributed in the outer suburb in a multi-core point pattern, both of which have clustering characteristics. (4) The results of the factor detector show that all seven influencing factors have an impact on the housing vacancy rate, but the degree of impact is different; the distance from CBD (Central Business District) has the strongest influence, while subway accessibility has the weakest influence. This study provides new ideas and methods for current research on urban housing vacancies, which can not only provide a reference for residents to purchase houses rationally, but also provide a decision-making basis for housing planning and policy formulation in megacities