Brunel University London

About: Brunel University London is a education organization based out in London, United Kingdom. It is known for research contribution in the topics: Context (language use) & Large Hadron Collider. The organization has 10918 authors who have published 29515 publications receiving 893330 citations. The organization is also known as: Brunel & University of Brunel.

Analysis of uniform binary subdivision schemes for curve design

Abstract: The paper analyses the convergence of sequences of control polygons produced by a binary subdivision scheme of the form $$\begin{array}{*{20}c} {f_{2i}^{k + 1} = \sum\limits_{j = 0}^m {a_j f_{i + j}^k } ,} & {f_{2i + 1}^{k + 1} = \sum\limits_{j = 0}^m {b_j f_{i + j}^k ,} } & {i \in Z,k = 0,1,2,....} \\ \end{array}$$ The convergence of the control polygons to aC° curve is analysed in terms of the convergence to zero of a derived scheme for the differencesf +1 −f . The analysis of the smoothness of the limit curve is reduced to the convergence analysis of “differentiated” schemes which correspond to divided differences off i k ∶i∈ Z with respect to the diadic parametrizationt =i/2 k . The inverse process of “integration” provides schemes with limit curves having additional orders of smoothness.

Optimal zonal wavelet-based ECG data compression for a mobile telecardiology system

Abstract: A new integrated design approach for an optimal zonal wavelet-based ECG data compression (OZWC) method for a mobile telecardiology model is presented. The hybrid implementation issues of this wavelet method with a GSM-based mobile telecardiology system are also introduced. The performance of the mobile system with compressed ECG data segments selected from the MIT-BIH arrhythmia database is evaluated in terms of bit error rate (BER), percent rms difference (PRD), and visual clinical inspection. The compression performance analysis of the OZWC is compared with another wavelet-based (Discrete Symmetric Wavelet Compression) approach. The optimal wavelet algorithm achieved a maximum compression ratio of 18:1 with low PRD ratios. The mobile telemedical simulation results show the successful compressed ECG transmission at speeds of 100 (km/h) with BER rates of less than 10/sup -15/, providing a 73% reduction in total mobile transmission time with clinically acceptable reconstruction of the received signals. This approach will provide a framework for the design and functionality issues of GSM-based wireless telemedicine systems with wavelet compression techniques and their future integration for the next generation of mobile telecardiology systems.

Late Quaternary aeolian activity in the Mu Us and Otindag dune fields (north China) and lagged response to insolation forcing

Abstract: [1] Dune fields in parts of northern China contain important stratigraphic records of late Quaternary change in the East Asian monsoon In this study, 33 new optically stimulated luminescence (OSL) ages and other measurements from aeolian sediment sections are used to reconstruct the timing of wet-dry climate variation in the Mu Us and Otindag dune fields of north China The results indicate dune activity and dry climate in the last few hundred years, 14 ka to about 7–8 ka, and 50 ka to 60 ka The dunes were mainly stable, implying a wetter climate, between about 7–8 ka and 24 ka These results imply a lag of several thousand years between peak summer insolation at 10–11 ka and high summer monsoon rainfall after 7–8 ka In the investigated regions, the monsoon climate may not respond directly to orbital forcing over millennial time scales Land surface feedbacks may account for lagged dune field response