Quantitative Analysis of Driving Factors of Grassland Degradation: A Case Study in Xilin River Basin, Inner Mongolia

Current literature suggests that grassland degradation occurs in areas with poor soil conditions or noticeable environmental changes and is often a result of overgrazing or human disturbances. However, these views are questioned in our analyses. Based on the analysis of satellite vegetation maps from 1984, 1998, and 2004 for the Xilin River Basin, Inner Mongolia, China, and binary logistic regression (BLR) analysis, we observe the following: (1) grassland degradation is positively correlated with the growth density of climax communities; (2) our findings do not support a common notion that a decrease of biological productivity is a direct indicator of grassland degradation; (3) a causal relationship between grazing intensity and grassland degradation was not found; (4) degradation severity increased steadily towards roads but showed different trends near human settlements. This study found complex relationships between vegetation degradation and various microhabitat conditions, for example, elevation, slope, aspect, and proximity to water

Research on maintenance decision making based on vibration data

Based on vibration data monitoring, by factors including vibration intensity and fault probability, system health state can be characterized, factors’ weight coefficients can be calculated, and health state function can be established, which are formal representation of system health state. Health state is divided into five levels, each level obtains its membership function by analyzing the characteristic of each factor. Using system health state as input of maintenance decision-making, predictive maintenance decision can be established. Good maintenance decision can efficiently reduce the maintenance cost and improve system availability. In this thesis, research on function expression of system health state based on vibration data was conducted. Then, using opportunity-group maintenance function based on system health state, maintenance decision was made

Part-Aware Product Design Agent Using Deep Generative Network and Local Linear Embedding

In this study, we present a data-driven generative design approach that can augment human creativity in product shape design with the objective of improving system performance. The approach consists of two modules: 1) a 3D mesh generative design module that can generate part-aware 3D objects using variational auto-encoder (VAE), and 2) a low-fidelity evaluation module that can rapidly assess the engineering performance of 3D objects based on locally linear embedding (LLE). This approach has two unique features. First, it generates 3D meshes that can better capture surface details (e.g., smoothness and curvature) given individual parts’ interconnection and constraints (i.e., part-aware), as opposed to generating holistic 3D shapes. Second, the LLE-based solver can assess the engineering performance of the generated 3D shapes to realize real-time evaluation. Our approach is applied to car design to reduce air drag for optimal aerodynamic performance

Uniqueness and uniform structural stability of Poiseuille flows with large fluxes in two-dimensional strips

In this paper, we prove the uniform nonlinear structural stability of Poiseuille flows with suitably large flux for the steady Navier-Stokes system in a two-dimensional strip with arbitrary period. Furthermore, the well-posedness theory for the Navier-Stokes system is also proved even when the $L^2$-norm of the external force is large. In particular, if the vertical velocity is suitably small where the smallness is independent of the flux, then Poiseuille flow is the unique solution of the steady Navier-Stokes system in the periodic strip. The key point is to establish uniform a priori estimates for the corresponding linearized problem via the boundary layer analysis, where we explore the particular features of odd and even stream functions. The analysis for the even stream function is new, which not only generalizes the previous study for the symmetric flows in \cite{Rabier1}, but also provides an explicit relation between the flux and period.Comment: arXiv admin note: substantial text overlap with arXiv:2011.0746

Looking into the Environmental Factors Affecting the Performance of Ubiquitous Technologies Deployment: An Empirical Study on Chinese Information and Communication Technology Companies

Effective deployment of ubiquitous technologies can help companies improve the business efficiency, especially for those ICT (Information communication technology) companies who are involved in M-business, M-commerce, and etc. However, there are many factors could affect the performance of the ubiquitous technologies deployment, such as the company’s management, the employee’s coordination, and etc. In this paper, we are focused on the environmental factors that would have an impact on the performance of organizations which have deployed or is deploying ubiquitous technologies, and investigate more than 50 Chinese ICT companies. According to our findings, in the context of China, a sensible, dependent, and interactive business relationship with the outside environment will have a positive impact on their ubiquitous technologies deployment’s performance, while the decentralization and hierarchism within organizational structure in the inside environment will have a negative impact on their ubiquitous technologies deployment’s performance

Improving the efficiency of polymer solar cells by incorporating gold nanoparticles into all polymer layers

We demonstrate efficiency improvement in polymer solar cells (PSCs) by ∼22 through incorporating Au nanoparticles (NPs) into all polymer layers. Au NPs are found to have distinct mechanisms in improving device performance when incorporated in different polymer layers. Au NPs in poly-(3,4- ethylenedioxythiophene):poly(styrenesulfonate) mainly contribute to better hole collection while Au NPs in active layer contributes to the enhanced optical absorption and more balanced charge-transport. Our theoretical result shows that the absorption enhancement at the active layer is attributed to plasmon resonances with strong near-field distributions penetrated into absorption polymers. These findings can be applied to design high-efficiency metallic NPs-incorporated PSCs. © 2011 American Institute of Physics.published_or_final_versio