http://bura.brunel.ac.uk/handle/2438/150 2013-05-20T13:45:47Z 2013-05-20T13:45:47Z Rohan, E Shaw, S Wheeler, MF Whiteman, JR http://bura.brunel.ac.uk/handle/2438/7418 2013-05-07T08:49:32Z 2013-01-01T00:00:00Z

Title: Mixed and galerkin finite element approximation of flow in a linear viscoelastic porous medium Authors: Rohan, E; Shaw, S; Wheeler, MF; Whiteman, JR Abstract: We propose two fully discrete mixed and Galerkin finite element approximations to a system of equations describing the slow flow of a slightly compressible single phase fluid in a viscoelastic porous medium. One of our schemes is the natural one for the backward Euler time discretization but, due to the viscoelasticity, seems to be stable only for small enough time steps. The other scheme contains a lagged term in the viscous stress and pressure evolution equations and this is enough to prove unconditional stability. For this lagged scheme we prove an optimal order a priori error estimate under ideal regularity assumptions and demonstrate the convergence rates by using a model problem with a manufactured solution. The model and numerical scheme that we present are a natural extension to ‘poroviscoelasticity’ of the poroelasticity equations and scheme studied by Philips and Wheeler in (for example) [Philip Joseph Philips, Mary F.Wheeler, Comput. Geosci. 11 (2007) 145–158] although — importantly — their algorithms and codes would need only minor modifications in order to include the viscous effects. The equations and algorithms presented here have application to oil reservoir simulations and also to the condition of hydrocephalus — ‘water on the brain’. An illustrative example is given demonstrating that even small viscoelastic effects can produce noticeable differences in long-time response. To the best of our knowledge this is the first time a mixed and Galerkin scheme has been analysed and implemented for viscoelastic porous media. Description: This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2013 Elsevier

2013-01-01T00:00:00Z Zhuang, Y Wang, Z Yu, H Wang, W Lauria, S http://bura.brunel.ac.uk/handle/2438/7367 2013-04-22T13:44:08Z 2013-01-01T00:00:00Z

Title: A robust extended H∞ filtering approach to multi-robot cooperative localization in dynamic indoor environments Authors: Zhuang, Y; Wang, Z; Yu, H; Wang, W; Lauria, S Abstract: Multi-robot cooperative localization serves as an essential task for a team of mobile robots to work within an unknown environment. Based on the real-time laser scanning data interaction, a robust approach is proposed to obtain optimal multi-robot relative observations using the Metric-based Iterative Closest Point (MbICP) algorithm, which makes it possible to utilize the surrounding environment information directly instead of placing a localization-mark on the robots. To meet the demand of dealing with the inherent non-linearities existing in the multi-robot kinematic models and the relative observations, a robust extended H∞ filtering (REHF) approach is developed for the multi-robot cooperative localization system, which could handle non-Gaussian process and measurement noises with respect to robot navigation in unknown dynamic scenes. Compared with the conventional multi-robot localization system using extended Kalman filtering (EKF) approach, the proposed filtering algorithm is capable of providing superior performance in a dynamic indoor environment with outlier disturbances. Both numerical experiments and experiments conducted for the Pioneer3-DX robots show that the proposed localization scheme is effective in improving both the accuracy and reliability of the performance within a complex environment. Description: This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2013 Elsevier.

2013-01-01T00:00:00Z Clarke, M Jones, R Fursse, J http://bura.brunel.ac.uk/handle/2438/7366 2013-04-22T13:34:17Z 2012-01-01T00:00:00Z

Title: Towards an integrated and interoperable platform for telehealth and telecare Authors: Clarke, M; Jones, R; Fursse, J Abstract: We present experience of implementing and evaluating a platform purpose designed to integrate interoperable telehealth and telecare. We chose the IEEE 11073 standards for all devices and used ZigBee wireless to support many devices concurrently and exploit its mesh networking to extend range around the entire house. We designed the home gateway to be unobtrusive; in project Hydra we used the smart meter and in other projects (Reaction, inCasa) we have developed a purpose designed plugtop ZigBee to GPRS gateway. All use common protocols and are interoperable. Technically the projects have been a success, and we have already implemented a wide range of devices on the common platform (BP, weight, SpO2, glucose, PIR, medication monitor, bed/chair sensor). Immediate feedback from participants has confirmed our goal of simplicity and convenience of use (and thus encourage adherence); and it is interesting that in discussion they then focus on the data rather than the technology. Our current goal is to exploit the potential for combination of physiological and environmental data to determine if change of habits can be detected and how this correlates with change in health. We are using this functionality to manage the frail elderly within project inCasa and we propose to present preliminary findings. Description: Copyright @ 2012 International Journal of Integrated Care (IJIC). This work is licensed under a (http://creativecommons.org/licenses/by/3.0) Creative Commons Attribution 3.0 Unported License.

2012-01-01T00:00:00Z Grzhibovskis, R Mikhailov, SE Rjasanow, S http://bura.brunel.ac.uk/handle/2438/7334 2013-04-23T13:58:24Z 2013-01-01T00:00:00Z

Title: Numerics of boundary-domain integral and integro-differential equations for BVP with variable coefficient in 3D Authors: Grzhibovskis, R; Mikhailov, SE; Rjasanow, S Abstract: A numerical implementation of the direct boundary-domain integral and integro-differential equations, BDIDEs, for treatment of the Dirichlet problem for a scalar elliptic PDE with variable coefficient in a three-dimensional domain is discussed. The mesh-based discretisation of the BDIEs with tetrahedron domain elements in conjunction with collocation method leads to a system of linear algebraic equations (discretised BDIE). The involved fully populated matrices are approximated by means of the H-Matrix/adaptive cross approximation technique. Convergence of the method is investigated. Description: This is the post-print version of the article. The official published version can be accessed from the links below - Copyright @ 2013 Springer-Verlag

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