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Journal of Hydrodynamics 2022年第5期34卷 806-825页

作者： Christopher J.Keylock School of Architecture Building and Civil EngineeringLoughborough UniversityLeicestershireUK

The Schur decomposition of the velocity gradient tensor(VGT)is an alternative to the classical Cauchy-Stokes decomposition into rotation rate and strain rate ***,there have been several strands of work that have employed this decomposition to examine the physics of turbulence dynamics,including approaches that combine the Schur and Cauchy-Stokes *** are briefly reviewed before the latter approach is set *** partitions the rotation rate and strain rate tensors into normal/local and non-normal/non-local *** then study the relation between the VGT dynamics and ejection-sweep events in a channel flow *** show that the sweeps in particular exhibit novel behaviour compared with either the other quadrants,or the flow in general,with a much-reduced contribution to the dynamics from the non-normal terms above the viscous *** particular,the reduction in the production term that is the interaction between the non-normality and the normal straining reduces in the log-layer as a consequence of an absence of alignment between the non-normal vorticity and the strain rate *** have been early forays into using the Schur transform approach for subgrid-scale modelling in large-eddy simulation(LES)and this would appear to be an exciting way forward.

关键词： Turbulence channel flow velocity gradient tensor Schur decomposition

The Interface Between Pragmatics and Conversation Analysis

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外国语 2018年第1期41卷 2-22页

作者： Paul Drew loughborough university UK

In his authoritative and brilliant account of Pragmatics,Levinson(1983)included Conversation Analysis(CA)firmly as part of *** have perhaps been more cautious,even sceptical,about whether CA is really relevant to the Pragmatics programme;and it has to be said that some conversation analysts have been rather stand-offish about being associated with Pragmatics,regarding CA’s programme as very different from that of *** there are many differences and divergences between CA and Pragmatics,my own view is that CA shares with Pragmatics a number of focal interests that lie at or close to the heart of *** I will explore some connections between them,focusing on the contributions CA makes to our understanding of the pragmatics of language use,especially in three of the foundational areas of Pragmatics—namely Implicature(*** Grice 1975),Speech Acts(social action)(*** Austin 1962 and Searle 1969)and Presupposition and Well-Formedness(*** Lakoff1971).I will show examples that demonstrate the distinctiveness of CA’s approach to these core pragmatic aspects of language use—in the spirit of demonstrating how CA’s approach complements and does not detract from approaches in Pragmatics.

关键词： conversation analysis sequential approach empirical complement pragmatics

Conversation Analysis and Social Action

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外国语 2013年第3期36卷 2-19页

作者： Paul Drew loughborough university UK

Conversation analysis(CA) has come to be regarded as focusing primarily on turn-taking,on the way speakers design,hold and extend their turns at talk;how they select next speakers;how others know when it is their turn to speak;how orderly transition from one turn to the next is managed and how turns *** argument in this paper is that this research focus is waning,and that in its place a new direction is emerging(or perhaps reemerging) -the investigation of how social actions are conducted through *** research direction connects with an area that is quite familiar in linguistic pragmatics,that of speech act analysis(Austin,Searle).But CA's approach is quite distinctive,exploring as it does the systematic basis for the selection of one from among the alternative constructions or formats for doing certain *** is illustrated through recent studies of offering and requesting,with some further observations of negatively formatted interrogatives used to make *** studies show that speakers select between the alternative available forms on the basis of the sequential position in which the speaker is conducting that action.

关键词：英语学习学习方法阅读知识阅读材料

Formal Reduction of Interfaces to Large-scale Process Control Systems

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International Journal of Automation and computing 2007年第4期4卷 413-421页

作者： Walter Hussak Department of Computer Science Loughborough UniversityLoughborough LE11 3TUUK

A formal methodology is proposed to reduce the amount of information displayed to remote human operators at interfaces to large-scale process control plants of a certain type. The reduction proceeds in two stages. In the first stage, minimal reduced subsets of components, which give full information about the state of the whole system, are generated by determining functional dependencies between components. This is achieved by using a temporal logic proof obligation to check whether the state of all components can be inferred from the state of components in a subset in specified situations that the human operator needs to detect, with respect to a finite state machine model of the system and other human operator behavior. Generation of reduced subsets is automated with the help of a temporal logic model checker. The second stage determines the interconnections between components to be displayed in the reduced system so that the natural overall graphical structure of the system is maintained. A formal definition of an aesthetic for the required subgraph of a graph representation of the full system, containing the reduced subset of components, is given for this purpose. The methodology is demonstrated by a case study.

关键词： Finite state machines process control temporal logic user interfaces user modeling.

Optimisation-based Verification Process of Obstacle Avoidance Systems for Unicycle-like Mobile Robots

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International Journal of Automation and computing 2011年第3期8卷 340-347页

作者： Sivaranjini Srikanthakumar Department of Aeronautical and Automotive Engineering Loughborough University

This paper presents an optimisatiombased verification process for obstacle avoidance systems of a unicycle-like mobile robot. It is a novel approach for the collision avoidance verification process. Local and global optimisation based verification processes are developed to find the worst-case parameters and the worst-case distance between the robot and an obstacle. The kinematic and dynamic model of the unicycle-like mobile robot is first introduced with force and torque as the inputs. The design of the control system is split into two parts. One is velocity and rotation using the robot dynamics, and the other is the incremental motion planning for robot kinematics. The artificial potential field method is chosen as a path planning and obstacle avoidance candidate technique for verification study as it is simple and widely used. Different optimisation algorithms are applied and compared for the purpose of verification. It is shown that even for a simple case study where only mass and inertia variations are considered, a local optimization based verification method may fail to identify the worst case. Two global optimisation methods have been investigated： genetic algorithms （GAs） and GLOBAL algorithms. Both of these methods successfully find the worst case. The verification process confirms that the obstacle avoidance algorithm functions correctly in the presence of all the possible parameter variations.

关键词： Verification process obstacle avoidance unicycle mobile robot potential field method optimisation.

The future of sustainable chemistry and process: Convergence of artificial intelligence, data and hardware

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Energy and AI 2020年第2期2卷 167-174页

作者： Xin Yee Tai Hao Zhang Zhiqiang Niu Steven D.R.Christie Jin Xuan Department of Chemical Engineering Loughborough UniversityLoughborough LE113TUUnited Kingdom School of Engineering The University of EdinburghEdinburgh EH93FBUnited Kingdom Department of Chemistry Loughborough UniversityLoughborough LE113TUUnited Kingdom

Sustainable chemistry for renewable energy generation and green synthesis is a timely research topic with the vision to provide present needs without compromising future *** the era of Industry 4.0,sustainable chemistry and process are undergoing a drastic transformation from continuous flow system toward the next level of operations,such as cooperating and coordinating machine,self-decision-making system,autonomous and automatic problem solver by integrating artificial intelligence,data and hardware in the cyber-physical *** to the lack of convergence between the physical and cyber spaces,the open-loop systems are facing challenges such as data isolation,slow cycle time,and insufficient resources *** researches have been devoted to accelerating these cycles,reducing the time between multistep processes and real-time characterization via additive manufacturing,in-/on-line monitoring,and artificial *** final goal is to concurrently propose process recipes,flow synthesis,and molecules characterization in sustainable chemical processes,with each step transmitting and receiving data *** process is known as‘closing the loop’,which will potentially create a future lab with highly integrated systems,and generate a service-orientated platform for end-to-end synchronization and self-evolving,inverse molecular design,and automatic science *** perspective provides a methodical approach for understanding cyber and physical systems individually,enabled by artificial intelligence and additive manufacturing,respectively,in combination with in-/on-line ***,the future perspective and key challenges for the development of the closed-loop system in sustainable chemistry and process are discussed.

关键词： Artificial intelligence In-/on-line monitoring Additive manufacturing

Optimal privatisation,and optimum-welfare and maximum-revenue tariffs

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Economic and Political Studies 2024年第2期12卷 220-234页

作者： Tien-Der Han Ruochen Li loughborough Business School Loughborough UniversityLoughboroughUK Centre for Economic Research Shandong UniversityJinanChina

We examine the effect of privatisation on the priority of the maximum-revenue tariff and the optimum-welfare tariff in an international mixed oligopoly with foreign competition and optimal *** demonstrate that when the marginal cost of the domestic privatised firm is high enough,the optimumwelfare tariff will exceed the maximum-revenue ***,due to the higher tariff rate that leads to the high degree of privatisation,the optimum-welfare tariff generates greater optimal privatisation than the maximum-revenue tariff ***,when the gap between the number of domestic private firms and that of their foreign counterparts becomes larger,the optimum-welfare tariff will exceed the maximum-revenue tariff.

关键词： Mixed oligopoly partial privatisation tariff ranking

Trajectory Generation for Autonomous Soaring UAS

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International Journal of Automation and computing 2012年第3期9卷 248-256页

作者： J. H. A. Clarke W. H. Chen Department of Aeronautical and Automotive Engineering Loughborough University

As unmanned aerial vehicles are expected to do more and more advanced tasks, improved range and persistence is required. This paper presents a method of using shallow layer cumulus convection to extend the range and duration of small unmanned aerial vehicles. A simulation model of an X-models XCalubur electric motor-glider is used in combination with a refined 4D parametric thermal model to simulate soaring flight. The parametric thermal model builds on previous successful models with refinements to more accurately describe the weather in northern Europe. The implementation of the variation of the MacCready setting is discussed. Methods for generating efficient trajectories are evaluated and recommendations are made regarding implementation.

关键词： Unmanned aerial vehicles (UAV) unmanned aerial systems (UAS) soaring trajectory thermal optimal heuristic

Chattering-free sliding mode control with unidirectional auxiliary surfaces for miniature helicopters

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International Journal of Intelligent Computing and Cybernetics 2012年第3期5卷 421-438页

作者： Jian Fu Wen-hua Chen Qing-xian Wu Department of Automation Nanjing University of Aeronautics and AstronauticsNanjingChina Department of Aeronautical and Automotive Engineering Loughborough UniversityLoughboroughUK

Purpose-This article proposes a chattering-free sliding mode control scheme with unidirectional auxiliary surfaces(UAS-SMC)for small miniature autonomous helicopters(Trex 250).Design/methodology/approach-The proposed UAS-SMC scheme consists of a nested sequence of rotor dynamics,angular rate,Euler angle,velocity and position ***-It is demonstrated that the UAS-SMC strategy can eliminate the chattering phenomenon exhibiting in the convenient SMC method and achieve a better approaching ***/value-The proposed control strategy is implemented on the helicopter and flight tests clearly demonstrate that a much better performance could be achieved,compared with convenient SMC schemes.

关键词： Unmanned aircraft Approaching speed Flight control Sliding mode control Helicopters Chattering

Multi-objective optimisation with hybrid machine learning strategy for complex catalytic processes

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Energy and AI 2022年第1期7卷 120-130页

作者： Xin Yee Tai Raffaella Ocone Steven D.R.Christie Jin Xuan Department of Chemical Engineering Loughborough UniversityLoughboroughLE113TUUK School of Engineering&Physical Science Heriot-Watt UniversityEdinburghEH144ASUK Department of Chemistry Loughborough UniversityLoughboroughLE113TUUK

Catalytic chemical processes such as hydrocracking,gasification and pyrolysis play a vital role in the renewable energy and net zero *** to the complex and non-linear behaviours during operation,catalytic chemical processes require a powerful modelling tool for prediction and optimisation for smart operation,speedy green process routes discovery and rapid process ***,challenges remain due to the lack of an effective modelling and optimisation toolbox,which requires not only a precise analysis but also a fast ***,we propose a hybrid machine learning strategy by embedding the physics-based continuum lumping kinetic model into the data-driven artificial neural network *** hybrid model is adopted as the surrogate model in the multi-objective optimisation and demonstrated in the benchmarking of a hydrocracking *** results show that the novel hybrid surrogate model exhibits the mean square error less than 0.01 by comparing with the physics-based simulation *** well-trained hybrid model was then integrated with non-dominated-sort genetic algorithm(NSGA-II)as the surrogate model to evaluate and optimise the yield and selectivity of the hydrocracking *** Pareto front from the multi-objective optimisation was able to identify the trade-off curve between the objective functions which is essential for the decision-making during process *** work indicates that adopting the hybrid machine learning strategy as the surrogate model in the multi-objective optimisation is a promising approach in various complex catalytic chemical processes to enable an accurate computation as well as a rapid optimisation.

关键词： Hybrid surrogate model Hybrid machine learning Multi-objective optimisation Catalytic chemical process