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Journal of Systems Science & Complexity 2018年第1期31卷 130-146页

作者： LIU Bin HILL david john ZHANG Changfan SUN Zhijie Department of Information and Computing Science Hunan University of Technology Zhuzhou 412008 China Department of Electrical and Electronic Engineering The University of Hong Kong Hong Kong China School of Electrical and Information Engineering Hunan University of Technology Zhuzhou 412008 China Mork Family Department of Chemical Engineering and Materials Science Viterbi School of Engineering University of Southern California Los Angeles CA 90089 USA

This paper investigates the issue of stabilization for discrete-time dynamical systems（DDS）by event-triggered impulsive control（ETIC）. Based on some relatively simple threshold constants, three levels of event conditions are set and thus the ETIC scheme is designed. Three cases for ETIC with and without time-delays and data dropouts are studied respectively, and the criteria on exponential stability are derived for the controlled DDS. The stabilization in the form of exponential stability is achieved for DDS under the designed ETIC with or without time-delays. And in the case of the ETIC data dropouts, the conditions of exponential stabilization are derived for DDS and the maximal allowable dropout rates for ETIC are estimated. Finally, one example with numerical simulations is worked out for illustration.

关键词： Data dropout discrete-time dynamical systems event-triggered control exponential stability impulsive control stabilization time-delay

Low-loss microwave photonics links using hollow core fibres

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Light(Science & Applications) 2022年第8期11卷 1891-1902页

作者： Xi Zhang Zitong Feng david Marpaung Eric Numkam Fokoua Hesham Sakr john Richard Hayes Francesco Poletti david john Richardson Radan Slavík Optoelectronics Research Centre University of SouthamptonSouthamptonSO171BJUK Laser Physics and Nonlinear Optics Group Faculty of Science and TechnologyMESA+Institute for NanotechnologyUniversity of TwenteEnschede7500 AEThe Netherlands

There are a host of applications in communications, sensing, and science, in which analogue signal transmission is preferred over today’s dominant digital transmission. In some of these applications, the advantage is in lower cost, while in others, it lies in superior performance. However, especially for longer analogue photonics links (up to 10 s of km), the performance is strongly limited by the impairments arising from using standard single-mode fibres (SSMF). Firstly, the three key metrics of analogue links (loss, noise figure, and dynamic range) tend to improve with received power, but this is limited by stimulated Brillouin scattering in SSMF. Further degradation is due to the chromatic dispersion of SSMF, which induces radio-frequency (RF) signal fading, increases even-order distortions, and causes phase-to-intensity-noise conversion. Further distortions still, are caused by the Kerr nonlinearity of SSMF. We propose to address all of these shortcomings by replacing SSMFs with hollow-core optical fibres, which have simultaneously six times lower chromatic dispersion and several orders of magnitude lower nonlinearity (Brillouin, Kerr). We demonstrate the advantages in this application using a 7.7 km long hollow-core fibre sample, significantly surpassing the performance of an SSMF link in virtually every metric, including 15 dB higher link gain and 6 dB lower noise figure.

关键词： nonlinearity microwave shortcomings

The rare Australian epiphytic orchid Sarcochilus weinthalii associates with a single species of Ceratobasidium

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Fungal Diversity 2012年第3期54卷 31-37页

作者： Rachel Roseanne Graham john david William Dearnaley Australian Centre for Sustainable Catchments The University of Southern QueenslandToowoombaQueensland 4350Australia

Sarcochilus weinthalii is a rare,epiphytic orchid largely restricted to the dry rainforests of eastern *** of the conservation procedures for the orchid includes isolation and identification of the associated mycorrhizal *** this study the mycorrhizal fungal partner of the species was determined through extraction and sequencing of DNA from both colonised orchid roots and pure fungal cultures grown out from orchid roots.A single species of Ceratobasidium predominated in the orchid suggesting that the orchid displays narrow fungal *** mycorrhizal fungus can now be used in conservation procedures involving ex situ growth and the reintroduction of plants to the natural state.

关键词： Sarcochilus weinthalii Epiphytic orchids Ceratobasidium Mycorrhizal specificity

An update on penile reconstruction

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Asian Journal of Andrology 2011年第3期13卷 391-394,511页

作者： Giulio Garaffa Amr Abdel Raheem david john Ralph St Peter＇s Andrology and the Institute Of Urology wig 6BJ London UK

Penile reconstruction still represents a formidable challenge for the urologist. In this review, the most recent advances in penile reconstruction after trauma, excision of benign and malignant disease and in patients... 详细信息

关键词： aphallia female-to-male sex reassignment surgery genital lymphoedema lichen sclerosus micropenis penile cancer penile trauma

Evolution and maintenance of cooperation via inheritance of neighborhood relationship

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Chinese Science Bulletin 2013年第28期58卷 3491-3498页

作者： TAN ShaoLin Lü JinHu YU XingHuo HILL david john The Key Laboratory of System and Control Institute of Systems ScienceAcademy of Mathematics and Systems ScienceChinese Academy of Sciences School of Electrical and Computer Engineering RMIT University Department of Electrical and Electronic Engineering The University of Hong Kong School of Electrical and Information Engineering University of Sydney

Cooperative behaviors are ubiquitous in nature and human *** is very important to understand the internal mechanism of emergence and maintenance of *** we know now,the offsprings inherit not only the phenotype but also the neighborhood relationship of their *** recent research results show that the interactions among individuals facilitate survival of cooperation through network reciprocity of clustering *** paper aims at introducing an inheritance mechanism of neighborhood relationship to explore the evolution of *** detail,a mathematical model is proposed to characterize the evolutionary process with the above inheritance *** analysis and numerical simulations indicate that high-level cooperation can emerge and be maintained for a wide variety of cost-to-benefit ratios,even if mutation happens during the evolving process.

关键词：合作机制邻里关系维护演变进化过程人类社会遗传机制数学模型

A bibliometric review on the implications of renewable offshore marine energy development on marine species

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Aquaculture and Fisheries 2022年第2期7卷 211-222页

作者： Siddharth Suhas Kulkarni david john Edwards School of Mechanical Aerospace and Automotive EngineeringCoventry UniversityGulson RoadCoventryCV12JHUK Department of Built Environment Birmingham City UniversityUK Faculty of Engineering and the Built Environment University of JohannesburgSouth Africa

The growing global demand for sustainable and environmentally friendly energy has stimulated the rapid adoption of renewable offshore ***,infrastructure needed for green energy production ironically impacts upon marine species and ***,this positional review paper seeks to comprehensively synthesise the prevailing body of knowledge on the impact of offshore energy development on a broad range of marine *** interpretivist philosophical stance and inductive reasoning was adopted using scientometric analysis to conduct a rich synthesis of extant *** an operational perspective,the Scopus database was utilised to search for key terms on the phenomena under investigation and using the VoS Viewer software for the identification of trends using scientometric *** analysis reveals that research in this area of science has increased significantly over the last decade but private sector involvement is conspicuous by its *** concerns among the research community include the impact of energy development on the abundance of species,pollution and biodiversity behaviour and *** present,researchers have extensively focused on the impact of offshore wind farms on fish and marine ***,the literature reveals no significant long-term impact upon energy development on most marine species albeit,short-term interference has raised concerns(from sound,disruption of navigation and foraging patterns,and damage of habitat).To minimise short term disruption,researchers have recommended the use of acoustic deterrence during construction,enforcement of protected areas and continued research.

关键词： Offshore energy development Wind farms Marine energy Marine species Animals Noise Infrastructure

Evaluation and Design of Alphabetic Communication Boards

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Applied Mathematics 2016年第2期7卷 125-129页

作者： david john Williams Department of Anaesthetics Morriston Hospital Swansea UK College of Medicine Swansea University Swansea UK

Communication boards provide a low-cost means of facilitating communication with patients who are unable to speak;however the process is slow and frustrating. A computer model was used to calculate the cumulative frequency-weighted path length for letter selection (“chart index”) for three conventional communication boards using different search strategies;and exhaustively generate and evaluate designs for a novel communication board based on a frequency-ordered arrangement of letters. For all arrangements, a 46% to 53% reduction in chart indices was achieved when “2 Dimensional” (2D) rather than “1 Dimensional” (1D) search strategies were employed. A further 23% to 30% reduction in chart indices was achieved through use of frequency-ordered sequences with optimal row groupings. Conventional communication boards can be used more efficiently by employing a 2D search strategy. Novel communication boards based on optimised arrangements of frequency-ordered letter sequences potentially provide a faster means of communication than conventional communication boards.

关键词： Combinatorics Compositions Frequency Analysis Medicine Ergonomics

Investigating the Effect of Fatigue on Fracturing Resistance of Rocks

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Journal of Civil Engineering and Architecture 2012年第10期6卷 1310-1318页

作者： Nazife Erarslan david john Williams Geoteehnical Engineering Centre School of Civil Engineering The University of Queensland Brisbane 4072 Australia

There is no doubt that an understanding of brittle rock fracturing is a key element in the solution of many engineering problems that involve rock structures. Some rock structures such as bridge and dam abutments and foundations, and tunnel walls, undergo both static and cyclic loading caused by drilling and blasting, and vehicle-induced vibrations. This type of loading often causes rock to fail at a lower than its static strength due to the effect of rock fatigue. A series of laboratory diametrical compression tests was performed on Brisbane tuff disc specimens to investigate their mode-I fracture toughness response to static and cyclic loading, as a function of the applied load. Both the static and cyclic loading tests were carried out on CCNBD （cracked chevron notched Brazilian disc） rock specimens. In the tests described herein, the reduction in fracture toughness under dynamic cyclic loading was found to be up to 48% of the static fracture toughness. Contrary to the static tests, the cyclic tests produced much more crushed material in front of the tip of the chevron notched crack.

关键词： Fracture toughness rock fatigue CCNBD SEM (scanning electron microscope)

Trajectory Controllability of Nonlinear Integro-Differential System—An Analytical and a Numerical Estimations

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Applied Mathematics 2012年第11期3卷 1729-1738页

作者： Dimplekumar Chalishajar Heena Chalishajar john david Mallory Hall Virginia Military Institute Lexington USA Roop Hall James Madison University Harrisonburg USA

A stronger concept of complete (exact) controllability which we call Trajectory Controllability is introduced in this paper. We study the Trajectory Controllability of an abstract nonlinear integro-differential system in the finite and infinite dimensional space setting. We will then discuss how approximations to these problems can be found computationally using finite difference methods and optimization. Examples will be presented in one, two and three dimensions.

关键词： Trajectory Controllability Monotone Operator Theory Set Valued Function Lipschitz Continuity Finite Difference Optimization

Comparison of X65 or Similar Line Pipe Steels with Different Microalloying Additions

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Comparison of X65 or Similar Line Pipe Steels with Different...