Rational spectral methods for PDEs involving fractional Laplacian in unbounded domains

Many PDEs involving fractional Laplacian are naturally set in unbounded domains with underlying solutions decay very slowly, subject to certain power laws. Their numerical solutions are under-explored. This paper aims at developing accurate spectral methods using rational basis (or modified mapped Gegenbauer functions) for such models in unbounded domains. The main building block of the spectral algorithms is the explicit representations for the Fourier transform and fractional Laplacian of the rational basis, derived from some useful integral identites related to modified Bessel functions. With these at our disposal, we can construct rational spectral-Galerkin and direct collocation schemes by pre-computing the associated fractional differentiation matrices. We obtain optimal error estimates of rational spectral approximation in the fractional Sobolev spaces, and analyze the optimal convergence of the proposed Galerkin scheme. We also provide ample numerical results to show that the rational method outperforms the Hermite function approach

A Comprehensive Learning-Based Model for Power Load Forecasting in Smart Grid

In the big data era, learning-based techniques have attracted more and more attention in many industry areas such as smart grid, intelligent transportation. The power load forecasting is one of the most critical issues in data analysis of smart grid. However, learning-based methods have not been widely used due to the poor data quality and computational capacity. In this paper, we propose a comprehensive learning-based model to forecast heavy and over load (HOL) accidents according to the data from various information systems. At first, we present a combined random under- and over-sampling technique for imbalanced electric data, and choose an optimal sampling rate through several experiments. Then, we reduce the attributes that have significant impact on the power load by using learning-based methods. Finally, we provide an algorithm based on the random forest method to prevent the over-fitting problem. We evaluate the proposed model and algorithms with the real-world data provided by China Grid. The experimental results show that our model works efficiently and achieves low error rates

Extended Use of Mobile Banking System: The Effects of Switching Cognitive Gears

The proliferation of mobile devices ushers a new era of financial services. Although various users already adopted mobile banking systems, their insufficient utilization of systems become a pressing issue. Encouraging individuals to engage in extended use, that is, applying more available system features to support their financial tasks, is an efficient approach for financial institutions to extract value from customers’ alreadyin-use mobile banking systems. However, a relevant theoretical account for such discretionary post-adoptive usage is still in its infancy. Based on the switching cognitive gears perspective, this study proposes four types of triggers (i.e., new tasks, changes in system environments, other people’s uses, and deliberate initiatives) that will prompt the active cognitive processing of individuals that leads to their extended use of mobile banking systems. We further propose the methodology to operationalize extended use and empirically validate the research model, and then discuss the possible theoretical contributions and practical implications

Understanding the Determinants of Review Helpfulness in Online Review Sites: An Empirical Study

Online review websites play an important role in customer’s purchase decision-making process for the useful product knowledge contained in the customer-generated reviews. However, the increasing information volume also makes it difficult for customers to identify and consider those attributes relevant to their decision. Based on Information Processing Theory (IPT) and Multiple Pathway Anchoring and Adjustment Model (MPAAM), we proposed three characteristics of online reviews affecting review helpfulness (e.g., attractiveness, representational sufficiency and functional sufficiency) and examined the moderating influences of information volume on these relationships. A large-scale review dataset from Yelp.com are collected and text analysis technique are applied to validate our research model. Our work, which illustrates the disturbance effect of information volume, has implications for both online word-of-mouth and information processing research

Visual Analysis of Crop Rotation Fallow Patterns in Recent 5 Years Based on CiteSpace

Based on the "Web of Science Core Collection" (SCIE database), this article used the visualization software CiteSpace to visualize and analyze the crop rotation fallow patterns in the past five years. It analyzed the countries, institutions, keywords and hot topics of related literature to explore their research characteristics and development, and to provide reference for crop rotation fallow research and practice. The research shows that: 1) developed countries are the main research force in the field of crop rotation and fallowing, and the connection between the research of each country and each institution is not close; 2) research hotspots can be mainly summarized as: crop growth and yield, greenhouse gas emissions and soil health analysis, and the research in this field is constantly refined, combining macro and micro; 3) In recent years, there is a big gap between China and foreign countries in the field of crop rotation and fallow research. It is necessary to strengthen the cooperation with research institutions in developed countries in Europe and the United States, and to carry out crossregional and interdisciplinary research cooperation to improve the quality of papers and scientific research level

A Review of Research on Ecological Economics Based on Bibliometrics

The development of ecological economics is a major strategy for development in the 21st century. Although scholars have been rising more and more interesting for ecological economic over the past 10 years, it is still unclear what is the change will be facing in the future. In order to provide a theoretical basis for the future development of ecological economy, our article analyzes the current research progress of ecological economy on the basis of a bibliometric analysis. The results show that (1) sustainable development of an ecological economy is a hot research topic; (2) there is little cooperation and exchange between institutions and among scholars regarding ecological economics; (3) the number of publications on ecological economics is increasing, with a relatively large number being published in China. Therefore, we must strengthen the cooperation between institutions and among scholars and improve the research content, vision, and methods in this field. This study provides a theoretical basis for the future development of ecological economy

Effect of irrigation frequency during the growing season of winter wheat on the water use efficiency of summer maize in a double cropping system

Our aim was to investigate the potential effects of irrigation frequency during the growing season of winter wheat on the water use efficiency (WUE) of summer maize in a double cropping system. To this end, we conducted a field experiment with winter wheat cultivated with 1, 2, and 3 irrigation applications with 120 mm water at the time of stem elongation, heading, or milking. The results showed that later irrigation applications increased soil moisture before sowing (SMBS) of summer maize. Summer maize grain yield was enhanced in both the common and excessively rainy years with increased SMBS; however, irrigation during the later growing season of winter wheat in rainy years could increase deep percolation of summer maize. In common and rainy years, the more the SMBS, the higher was the grain yield of summer maize. The highest WUE for summer maize was obtained when it was grown after winter wheat irrigated with 120 mm water at milking or 60 mm water at each, the stem elongation and heading stages. Considering the combined WUE of winter wheat and summer maize, the authors think that winter wheat should be irrigated at the stem elongation and heading stages to achieve reasonable WUE and grain yield for both crops