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In this paper, a terminal fractional-order observer and a terminal disturbance observer is proposed to estimate internal states and external disturbances of the class of fractional-order chaotic systems. The estimation of states within fixed time is achieved by employing a nonlinear feedback in terms of the observer error. The fixed convergence time is not relevant to the initial conditions and can be adjusted to any desired values by tuning the designable parameters. Finally, the numerical simulations are performed on fractional-order chaotic Liu, Chen, and Financial systems to validate the theoretical results. Moreover, some numerical simulations are provided to compare the obtained theoretical results with the other methods in the literature. [ABSTRACT FROM AUTHOR]

The quest to generate distributions with more desirable and flexible properties for the modeling of data has led to an intense focus on the development of new families that are generalizations of existing distributions by researchers. A new family of distributions called the chen generated family is developed in this study. Its statistical properties such as the quantile, moments, incomplete moments, stochastic ordering and order statistics are derived by using the method of maximum likelihood, estimators for the parameters of the new family are developed. Three special distributions, Chen Burr III, Chen Kumaraswamy and Chen Weibull, are proposed from the new family, though it can generalize other distributions. A demonstration of the usefulness of the new family is performed using real dataset. [ABSTRACT FROM AUTHOR]

In order to solve the shortcomings of the traditional serial encryption method in single machine mode, such as the low density of data security, the difficulty in encrypting-efficiency to meet the requirement of increasing information data encryption and the excessive amount of memory in the running process, and so on. This paper designed a scheme of chaotic encryption algorithm based on Hadoop platform. The scheme used MapReduce parallel framework, chaotic encryption pseudorandom number and the principle of initial value sensitivity. And it proposed parallel chaotic encryption scheme for MapReduce framework and chaotic encryption optimization. It used the length of the plaintext as the initial value, and used Chen, Lorenz, Rossler chaotic system to generate secret key. At the same time, the paper proposed an idea of dividing plaintext data into blocks according to 1 MB. According to the offset, it judged each block to gene rate three key sequences of Chenn Lorenzi R0ssler whose length is 1 MB, to improve the security of data density, and reduce the amount of running memory and other purposes. This design framework used Chen sequence for plaintext messing operation, used Lorenz sequence for XOR diffusion ope ration and used Rössler sequence for modular auxiliary diffusion operation. Experiments prove that, for MapReduce, the optimization algorithm of using parallel framework and chaotic system can effectively reduce the amount of memory and improve the encryption speed, and the encryption ope ration associated with plaintext achieves the purpose of effectively defending against the attack of selected plaintext. [ABSTRACT FROM AUTHOR]

The chaotic map has complex dynamics under ideal conditions however it suffers from the problem of performance degradation in the case of finite computing precision. In order to prevent the dynamics degradation, in this paper the continuous Chen chaotic system is used to perturb both the inputs and parameters of Chebyshev map to minimize the chaotic degradation phenomenon under finite precision. Experimental evaluations and corresponding performance analysis demonstrate that the Chebyshev chaotic map has a good randomness and complex dynamic performance by using the proposed perturbation method, and some attributes of the proposed system are stronger than the original system (e.g. chaos attractor and approximate entropy). Finally, the corresponding pseudorandom number generator (PRNG) is constructed by this method and then its randomness is evaluated via NIST SP800-22 and TestU01 test suites, respectively. Statistical test results show that the proposed PRNG has high reliability of randomness, thus it can be used for cryptography and other potential applications. [ABSTRACT FROM AUTHOR]

Background The human uterus is traditionally believed to be sterile, while the vaginal microbiota plays an important role in fending off pathogens. Emerging evidence demonstrates the presence of bacteria beyond the vagina. However, a microbiome-wide metagenomic analysis characterizing the diverse microbial communities has been lacking. Results We performed shotgun-sequencing of 52 samples from the cervical canal and the peritoneal fluid of Chinese women of reproductive age using the Illumina platform. Direct annotation of sequencing reads identified the taxonomy of bacteria, archaea, fungi and viruses, confirming and extending the results from our previous study. We replicated our previous findings in another 24 samples from the vagina, the cervical canal, the uterus and the peritoneal fluid using the BGISEQ-500 platform revealing that microorganisms in the samples from the same individuals were largely shared in the entire reproductive tract. Human sequences made up more than 99% of the 20GB raw data. After filtering, vaginal microorganisms were well covered in the generated reproductive tract gene catalogue, while the more diverse upper reproductive tract microbiota would require greater depth of sequencing and more samples to meet the full coverage scale. Conclusions We provide novel detailed data on the microbial composition of a largely unchartered body site, the female reproductive tract. Our results indicated the presence of an intra-individual continuum of microorganisms that gradually changed from the vagina to the peritoneal fluid. This study also provides a framework for understanding the implications of the composition and functional potential of the distinct microbial ecosystems of the female reproductive tract in relation to health and disease. [ABSTRACT FROM AUTHOR]

Recounts the career and contributions of Xiaojie Chen. [ABSTRACT FROM PUBLISHER]

The Editor-in-Chief announces the appointment of a new member to the Editorial Board: Professor Kevin Chen of The Hong Kong University of Science and Technology, Kowloon, Hong Kong, in the area of compound semiconductor devices. Kevin is a recognized expert in this field. A short biography of Kevin is provided. [ABSTRACT FROM AUTHOR]