Finite-time stability and stabilization of nonlinear stochastic hybrid systems

AbstractThis paper deals with the problem of finite-time stability and stabilization of nonlinear Markovian switching stochastic systems which exist impulses at the switching instants. Using multiple Lyapunov function theory, a sufficient condition is established for finite-time stability of the underlying systems. Furthermore, based on the state partition of continuous parts of systems, a feedback controller is designed such that the corresponding impulsive stochastic closed-loop systems are finite-time stochastically stable. A numerical example is presented to illustrate the effectiveness of the proposed method

Finite Time Stability of Stochastic Hybrid Systems

This paper considers the finite time stability of stochastic hybrid systems, which has both Markovian switching and impulsive effect. First, the concept of finite time stability is extended to stochastic hybrid systems. Then, by using common Lyapunov function and multiple Lyapunov functions theory, two sufficient conditions for finite time stability of stochastic hybrid systems are presented. Furthermore, a new notion called stochastic minimum dwell time is proposed and then, combining it with the method of multiple Lyapunov functions, a sufficient condition for finite time stability of stochastic hybrid systems is given. Finally, a numerical example is provided to illustrate the theoretical results

Invasive Chloroplast Population Genetics of Mikania micrantha in China: No Local Adaptation and Negative Correlation between Diversity and Geographic Distance

Two fundamental questions on how invasive species are able to rapidly colonize novel habitat have emerged. One asks whether a negative correlation exists between the genetic diversity of invasive populations and their geographic distance from the origin of introduction. The other is whether selection on the chloroplast genome is important driver of adaptation to novel soil environments. Here, we addressed these questions in a study of the noxious invasive weed, Mikania micrantha, which has rapidly expanded in to southern China after being introduced to Hong Kong in 1884. Seven cpSSRs were used to investigate population genetics in twenty-eight populations of M. micrantha, which produced thirty-nine loci. The soil compositions for these populations, including Mg abundance, were measured. The results showed that M. micrantha possessed relatively high cpSSR variation and differentiation among populations. Multiple diversity indices were quantified, and none was significantly correlated with distance from the origin of introduction. No evidence for isolation by distance, significant spatial structure, bottlenecks, nor linkage disequilibrium was detected. We also were unable to identify loci on the chloroplast genome that exhibited patterns of differentiation that would suggest adaptive evolution in response to soil attributes. Soil Mg has only a genome-wide effect instead of being a selective factor, which highlighted the association between Mg and the successful invasion. This study characterizes the role of the chloroplast genome of M. micrantha during its recent invasion of southern China

Mouthwash use and cancer of the head and neck: a pooled analysis from the International Head and Neck Cancer Epidemiology Consortium

Most mouthwashes contain alcohol, a known cause of head and neck cancer (oral cavity, pharynx, larynx), likely through the carcinogenic activity of acetaldehyde, formed in the oral cavity from alcohol

Vitamin or mineral supplement intake and the risk of head and neck cancer: pooled analysis in the INHANCE consortium

To investigate the potential role of vitamin or mineral supplementation on the risk of head and neck cancer (HNC), we analyzed individual-level pooled data from 12 case-control studies (7,002 HNC cases and 8,383 controls) participating in the International Head and Neck Cancer Epidemiology consortium. There were a total of 2,028 oral cavity cancer, 2,465 pharyngeal cancer, and 874 unspecified oral/pharynx cancer, 1,329 laryngeal cancer and 306 overlapping HNC cases. Odds ratios (OR) and 95% confidence intervals (CIs) for self reported ever use of any vitamins, multivitamins, vitamin A, vitamin C, vitamin E, and calcium, beta-carotene, iron, selenium, and zinc supplements were assessed. We further examined frequency, duration and cumulative exposure of each vitamin or mineral when possible and stratified by smoking and drinking status. All ORs were adjusted for age, sex, race/ethnicity, study center, education level, and pack-years of smoking, frequency of alcohol drinking and fruit/vegetable intake. A decreased risk of HNC was observed with ever use of vitamin C (OR=0.76, 95% CI=0.59-0.96) and with ever use of calcium supplement (OR=0.64, 95% CI=0.42-0.97). The inverse association with HNC risk was also observed for 10 or more years of vitamin C use (OR=0.72, 95% CI=0.54-0.97) and more than 365 tablets of cumulative calcium intake (OR=0.36, 95% CI=0.16-0.83), but linear trends were not observed for the frequency or duration of any supplement intake. We did not observe any strong associations between vitamin or mineral supplement intake and the risk of head and neck cancer

06_日軍侵港與聖士提反書院

1941年12月8日，日軍渡過深圳河正式向香港發動侵略戰。至平安夜，日軍攻至英軍在港島南端最後的一個據點—赤柱，兩軍爆發激戰。最終港督楊慕奇在聖誕日宣佈投降，為香港三年零八個月的艱苦歲月正式揭開了序幕。現時赤柱仍遺下不少日軍侵略及管治的遺址，其中設於聖士堤反書院內的文物徑更為這段歷史保留了甚為珍貴的文化財產。https://commons.ln.edu.hk/jchkhlp_trips/1006/thumbnail.jp

08_日軍侵港與聖士提反書院

1941年12月8日，日軍渡過深圳河正式向香港發動侵略戰。至平安夜，日軍攻至英軍在港島南端最後的一個據點—赤柱，兩軍爆發激戰。最終港督楊慕奇在聖誕日宣佈投降，為香港三年零八個月的艱苦歲月正式揭開了序幕。現時赤柱仍遺下不少日軍侵略及管治的遺址，其中設於聖士堤反書院內的文物徑更為這段歷史保留了甚為珍貴的文化財產。https://commons.ln.edu.hk/jchkhlp_talks/1008/thumbnail.jp

Stability analysis and H∞ control of discrete T–S fuzzy hyperbolic systems

This paper focuses on the problem of constraint control for a class of discrete-time nonlinear systems. Firstly, a new discrete T–S fuzzy hyperbolic model is proposed to represent a class of discrete-time nonlinear systems. By means of the parallel distributed compensation (PDC) method, a novel asymptotic stabilizing control law with the “soft” constraint property is designed. The main advantage is that the proposed control method may achieve a small control amplitude. Secondly, for an uncertain discrete T–S fuzzy hyperbolic system with external disturbances, by the proposed control method, the robust stability and H∞ performance are developed by using a Lyapunov function, and some sufficient conditions are established through seeking feasible solutions of some linear matrix inequalities (LMIs) to obtain several positive diagonally dominant (PDD) matrices. Finally, the validity and feasibility of the proposed schemes are demonstrated by a numerical example and a Van de Vusse one, and some comparisons of the discrete T–S fuzzy hyperbolic model with the discrete T–S fuzzy linear one are also given to illustrate the advantage of our approach