1,721,002 research outputs found
Multiobjective gas turbine engine controller design using genetic algorithms
No full textThis paper describes the use of multiobjective genetic algorithms (MOGAs) in the design of a multivariable control system for a gas turbine engine. The mechanisms employed to facilitate multiobjective search with the genetic algorithm are described with the aid of an example. It is shown that the MOGA confers a number of advantages over conventional multiobjective optimization methods by evolving a family of Pareto-optimal solutions rather than a single solution estimate. This allows the engineer to examine the trade-offs between the different design objectives and configurations during the course of an optimization. In addition, the paper demonstrates how the genetic algorithm can be used to search in both controller structure and parameter space thereby offering a potentially more general approach to optimization in controller design than traditional numerical methods. While the example in the paper deals with control system design, the approach described can be expected to be applicable to more general problems in the fields of computer aided design (CAD) and computer aided engineering (CAE
Flow motion dynamics of microvascular blood flow and oxygenation - evidence of adaptive changes in obesity and type 2 diabetes mellitus/insulin resistance
No full textAn altered spatial heterogeneity and temporal stability of network perfusion can give rise to a limited adaptive ability to meet metabolic demands. Derangement of local flow motion activity is associated with reduced microvascular blood flow and tissue oxygenation and it has been suggested that changes in flow motion activity may provide an early indicator of declining, endothelial, neurogenic and myogenic regulatory mechanisms and signal the onset and progression of microvascular pathophysiology. This short conference review article explores some of the evidence for altered flow motion dynamics of blood flux signals acquired using laser Doppler fluximetry in the skin in individuals at risk of developing or with cardio-metabolic disease
Optimal coordination of vehicle-to-grid batteries and renewable generators in a distribution system
Full text linkThe increasing penetration of electric vehicles (EVs) and renewable generators (RGs) in the power grid is an inevitable trend to combat air pollution and reduce the usage of fossil fuels. This will challenge distribution networks, which have constrained capacity. However, appropriate dispatch of electric vehicles via vehicle-to-grid (V2G) operation in coordination with the distributed renewable generators can provide support for the grid, reduce the reliance on traditional fossil-fuel generators and benefit EV users. This paper develops a novel agent-based coordinated dispatch strategy for EVs and distributed renewable generators, taking into account both grid's and EV users' concerns and priorities. This optimal dispatch problem is formulated as a distributed multi-objective constraint optimisation problem utilizing the Analytic Hierarchy Process and is solved using a dynamic-programming-based algorithm. The proposed strategy is tested on a modified UK Generic Distribution System (UKGDS). The electricity network model is simplified using a virtual sub-node concept to alleviate the computation burden of a node's agent. Simulation results demonstrate the feasibility and stability of this dispatch strategy
Coordinating electric vehicle flow distribution and charger allocation by joint optimization
No full textA two-stage stochastic programming model is established to minimize EV's expected total journey time under stochastic traffic conditions, by jointly optimizing the allocation of chargers and the distribution of EV flows. Based on sample average approximation, a feasible deterministic equivalent of the original stochastic problem is obtained. Then, a hybrid solution method, composing of a Tabu-based search and sequential quadratic programming (SQP), is proposed. The Tabu heuristic manages the charger allocation problem, where each solution candidate undergoes a second-stage EV flow optimization. SQP is applied to optimially distribute the EV flows, which is proved to be a convex problem. Extensive simulations are carried out using the eastern Massachusetts highway network. Results show that the proposed algorithm outperforms existing approaches. Additionally, the two-stage model designates charging resource sufficiency by estimating a lower bound for the number of chargers to allocate, which in practice helps to prevent over-investment on charging resources.</p
Data-Raspberry data for 'Wearable multimodal skin sensing for the diabetic foot'
No full textThis data is supplied in support of the the article "Wearable multimodal skin sensing for the diabetic foot" by Coates, Chipperfield and Clough in the open access journal 'electronics - Raspberry Pi Special edition'.
A data set is provided for each volunteer referenced as 001, 009 and 1001 are enclosed. Biomentric data is supplied for each volunteer along with the data set used in the article. The title of each graph presented in the article identifies the data set used together with the chosen data filter type (low pass) and filter cut off frequency. TA 6 pole Butterwoth filter was used. Data was analysed in Python Spyder 2.3.5.2.
Data is taken in time series with a descriptor of the data stream collected in row 5 of the respective column. The unis for each data stream is in row 6. All data ws taken at 20Hz.</span
Dataset: Analysis of microvascular blood flow and oxygenation: discrimination between two haemodynamic steady states using nonlinear measures and multiscale analysis
No full textDataset supports: Thanaj, M., Chipperfield, A. J., & Clough, G. F. (2018). Analysis of microvascular blood flow and oxygenation: Discrimination between two haemodynamic steady states using nonlinear measures and multiscale analysis. Computers in Biology and Medicine, 102, 157-167.</span
Dataset supporting the thesis entitled "Developing a Framework for an Adaptive Transtibial Prosthetic Socket using FEA-based Tissue Injury Risk Estimation and Generalised Predictive Control"
No full textRaw data behind simulations and figures for the thesis entitled "Developing a Framework for an Adaptive Transtibial Prosthetic Socket using FEA-based Tissue Injury Risk Estimation and Generalised Predictive Control", University of Southampton, 2020</span
Multi-objective optimization approach to the ALSTOM gasifier problem
Full text linkA control system design procedure based on the optimization of multiple objectives is used to realize the control design specifications of the linear gasification plant models. A multi-objective genetic algorithm (MOGA) is used in conjunction with an H? loop-shaping design procedure (LSDP) in order to satisfy the requirements of this critical system. The H? LSDP is used to guarantee the stability and robustness of the controller while its associated weighting matrix parameters are selected using the multi-objective search method in order to achieve performance requirements. A controller emerges which is stable but unable to completely meet some of the control objectives. Despite this shortcoming, the study is an excellent vehicle for introduction to an effective H? loop-shaping procedure. Further work, beyond the scope of this challenge has subsequently produced an improved controller desig
Predictive control for an active prosthetic socket informed by FEA-based tissue damage risk estimation
No full textThis paper presents an architecture for generalized predictive control for an active prosthetic socket system, based on a cost function performance index measure for minimization of residual limb tissue injury. Finite element analysis of a transtibial residuum model donned with a total surface bearing socket was used to provide controller training data and biomechanical rationale for deep tissue injury risk assessment, by estimating the internal deformation state of the soft tissues and the residuum-socket interface loading under a range of prosthetic loading instances. The results demonstrate the concept of this approach for interface actuation modelled as translational spring and damper systems
Data - Time-dependent Behavior of Microvascular Blood Flow and Oxygenation: a Predictor of Functional Outcomes
No full textThis data is supplied in support of the the article "Time-dependent Behavior of Microvascular Blood Flow and Oxygenation: a Predictor of Functional Outcomes" by Katarzyna Z. Kuliga, Rodney Gush, Geraldine F. Clough and Andrew J. Chipperfield published in IEEE Transactions on Biomedical Engineering, 2017.
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