The global sliding mode tracking control for a class of variable order fractional differential systems

In this paper, a novel variable order fractional control approach is proposed for tracking control of both of variable order fractional and constant order fractional order system with uncertain and external disturbance terms. In term of the global sliding mode control theory and terminal sliding mode control method, the system states are guaranteed to stay on the switching surface from the initial time, and then converge to the origin by the designed controllers which are continuous input signals. Such controllers avoid the undesirable chattering and remove the effects of uncertain and external disturbance completely. Finally, the comparison between the variable order fraction controller and the constant order fractional controller is given by numerical simulation, furthermore, numerical results on the effects of the tracking control are provided.This paper has been supported by National Natural Science Foundation of China (No.12002194; No.12072178; No.11732005), Natural Science Foundation of Shandong Province (No.ZR2020QA037; No.ZR2020MA054), Ministerio de Ciencia, Innovación y Universidades (No. PGC2018-097198-B-I00) and Fundación Séneca de la Región de Murcia (No.20783/PI/18)

Characteristics of Familial Lung Cancer in Yunnan-Guizhou Plateau of China

Background: Lung cancer has inherited susceptibility and show familial aggregation, the characteristics of familial lung cancer exhibit population heterogeneity. Despite previous studies, familial lung cancer in China's Yunnan-Guizhou plateau remains understudied.Methods: Between 2015 and 2017, 1,023 lung cancer patients (residents of Yunnan-Guizhou plateau) were enrolled with no limitation on other parameters, 152 subjects had familial lung cancer. Clinicopathologic parameters were analyzed and compared, 4,754 lung cancer patients from NCI-GDC were used to represent a general population.Results: Familial lung cancer (FLC) subjects showed unique characters: early-onset; increased rate of female, adenocarcinoma, stage IV and other cancer history; unbalance in anatomic sites; all ruling out significant difference in smoking status. Unbalanced distribution of co-existing diseases or symptoms was also discovered. FLC patients were more likely to develop benign lesions (polyps, nodules, cysts) early in life, especially early-growth of multiple pulmonary nodules at higher frequency. Typical diseases with family history like diabetes and hypertension were also increased in FLC population. Compared to GDC data, our subject population was younger: the age peak of our FLC group was in 50–59; our sporadic group had an age peak around 60; while GDC patients' age peak was in 60–69. Importantly, the biggest difference happened in age 40–49: our FLC group and sporadic group had 3 times and 2 times higher ratio than GDC population, respectively. Moreover, the age peaks of our FLC males and FLC females were both in 50–59; while our sporadic females had the age peak in 50–59, much earlier than sporadic males (around 60–69); reflecting gender-specific or age-specific characters in our subject population.Conclusions: Familial lung cancer in China's Yunnan-Guizhou plateau showed unique clinicopathologic characters, differences were found in gender, age, histologic type, TNM stage and co-existing diseases or symptoms. Identification of hereditary factors which lead to increased lung cancer risk will be a challenge of both scientific and clinical significance

A Parameter Estimation Method for Nonlinear Systems Based on Improved Boundary Chicken Swarm Optimization

Parameter estimation is an important problem in nonlinear system modeling and control. Through constructing an appropriate fitness function, parameter estimation of system could be converted to a multidimensional parameter optimization problem. As a novel swarm intelligence algorithm, chicken swarm optimization (CSO) has attracted much attention owing to its good global convergence and robustness. In this paper, a method based on improved boundary chicken swarm optimization (IBCSO) is proposed for parameter estimation of nonlinear systems, demonstrated and tested by Lorenz system and a coupling motor system. Furthermore, we have analyzed the influence of time series on the estimation accuracy. Computer simulation results show it is feasible and with desirable performance for parameter estimation of nonlinear systems

A general lithography-free method of microscale/nanoscale fabrication and patterning on Si and Ge surfaces

Here, we introduce and give an overview of a general lithography-free method to fabricate silicide and germanide micro-/nanostructures on Si and Ge surfaces through metal-vapor-initiated endoepitaxial growth. Excellent controls on shape and orientation are achieved by adjusting the substrate orientation and growth parameters. Furthermore, micro-/nanoscale pits with controlled morphologies can also be successfully fabricated on Si and Ge surfaces by taking advantage of the sublimation of silicides/germanides. The aim of this brief report is to illustrate the concept of lithography-free synthesis and patterning on surfaces of elemental semiconductors, and the differences and the challenges associated with the Si and the Ge surfaces will be discussed. Our results suggest that this low-cost bottom-up approach is promising for applications in functional nanodevices

How Risk Prevention Mechanisms Regulate Serial Entrepreneurs to Achieve Sustainable Entrepreneurship—A Policy Text Analysis

With the advent of the “Industry 4.0” era, the outbreak of the new epidemic, and the frequent occurrence of economic crises, sustainable entrepreneurship has led to the entrepreneurial ambition of serial entrepreneurs. Although a large number of supportive policies have been recently enacted by administrations at all levels to promote sustainable entrepreneurship among serial entrepreneurs, there is a lack of policy evaluation. In addition, although academics recognize the importance of policy regulation in leading sustainable entrepreneurship, in-depth research on the entrepreneurship policy system is still lacking. Based on this, this paper applied the “policy instrument–policy target” analysis framework and selected Chinese policy texts that support the sustainable entrepreneurship of serial entrepreneurs for textual content analysis. The results of this paper suggest that the synergy of various policy instruments and the appropriateness of the policy instrument–target fit need to be improved. The findings of this paper can provide a theoretical basis and practical implications for governmental entities to guide serial entrepreneurs to prevent social, economic, and environmental risks and achieve sustainable entrepreneurship goals

How Risk Prevention Mechanisms Regulate Serial Entrepreneurs to Achieve Sustainable Entrepreneurship—A Policy Text Analysis

With the advent of the “Industry 4.0” era, the outbreak of the new epidemic, and the frequent occurrence of economic crises, sustainable entrepreneurship has led to the entrepreneurial ambition of serial entrepreneurs. Although a large number of supportive policies have been recently enacted by administrations at all levels to promote sustainable entrepreneurship among serial entrepreneurs, there is a lack of policy evaluation. In addition, although academics recognize the importance of policy regulation in leading sustainable entrepreneurship, in-depth research on the entrepreneurship policy system is still lacking. Based on this, this paper applied the “policy instrument–policy target” analysis framework and selected Chinese policy texts that support the sustainable entrepreneurship of serial entrepreneurs for textual content analysis. The results of this paper suggest that the synergy of various policy instruments and the appropriateness of the policy instrument–target fit need to be improved. The findings of this paper can provide a theoretical basis and practical implications for governmental entities to guide serial entrepreneurs to prevent social, economic, and environmental risks and achieve sustainable entrepreneurship goals

Entrepreneurial Experience and Performance: From the Aspect of Sustainable Growth of Enterprises

In the uncertain entrepreneurial ecosystem, scholarly knowledge is bounded by the sustainable growth of entrepreneurial enterprises. Moreover, there is a lack of consensus in academic circles on the relationship between entrepreneurial experience and entrepreneurial performance. In adopting the meta-analysis method, we found a significant relationship between entrepreneurial experience and entrepreneurial performance based on an investigation of 45 independent samples (N = 18,752). We also examined theoretically derived moderators of this relationship referring to firm age, industry condition and experience type to test whether the moderating effects can explain the inconsistent research results on the relationship between entrepreneurial experience and entrepreneurial performance. The relationship was stronger for the high-tech industry than for low-tech industry, for the early business stage than for late business stage and for start-up experience compared to management experience, work experience and industry experience. Our research findings are meaningful for practitioners to achieve sustainable growth by better preserving and coordinating entrepreneurial experience in a dynamic environment. Further, these findings are also important for future research to analyze the factors triggering the heterogeneity of entrepreneurial experience and to investigate the extent to which the start-up experience is more capable of promoting entrepreneurial performance.Funding Agencies|Ministry of Education of Humanities and Social Science Project [18YJA630086]; Fundamental Research Funds for the Central UniversitiesFundamental Research Funds for the Central Universities [2019GYZX003, 2019-JL-004]</p

Modeling Uncertainty of Directed Movement via Markov Chains

Probabilistic time geography (PTG) is suggested as an extension of (classical) time geography, in order to present the uncertainty of an agent located at the accessible position by probability. This may provide a quantitative basis for most likely finding an agent at a location. In recent years, PTG based on normal distribution or Brown bridge has been proposed, its variance, however, is irrelevant with the agent's speed or divergent with the increase of the speed; so they are difficult to take into account application pertinence and stability. In this paper, a new method is proposed to model PTG based on Markov chain. Firstly, a bidirectional conditions Markov chain is modeled, the limit of which, when the moving speed is large enough, can be regarded as the Brown bridge, thus has the characteristics of digital stability. Then, the directed movement is mapped to Markov chains. The essential part is to build step length, the state space and transfer matrix of Markov chain according to the space and time position of directional movement, movement speed information, to make sure the Markov chain related to the movement speed. Finally, calculating continuously the probability distribution of the directed movement at any time by the Markov chains, it can be get the possibility of an agent located at the accessible position. Experimental results show that, the variance based on Markov chains not only is related to speed, but also is tending towards stability with increasing the agent's maximum speed