An empirical relationship to determine lateral seismic response of mid‐rise building frames under influence of soil–structure interaction

In this study, to determine the elastic and inelastic structural responses of mid‐rise building frames under the influence of soil–structure interaction, three types of mid‐rise moment‐resisting building frames, including 5‐storey, 10‐storey and 15‐storey buildings are selected. In addition, three soil types with the shear wave velocities less than 600 m/s, representing soil classes C_e, D_e and E_e according to AS 1170.4–2007 (Earthquake action in Australia, Australian Standards), having three bedrock depths of 10 m, 20 m and 30 m are adopted. The structural sections are designed after conducting nonlinear time history analysis, on the basis of both elastic method and inelastic procedure considering elastic‐perfectly plastic behaviour of structural elements. The frame sections are modelled and analysed, employing finite difference method adopting FLAC2D software under two different boundary conditions: (a) fixed base (no soil–structure interaction) and (b) considering soil–structure interaction. Fully nonlinear dynamic analyses under the influence of different earthquake records are conducted, and the results in terms of the maximum lateral displacements and base shears for the above mentioned boundary conditions for both elastic and inelastic behaviours of the structural models are obtained, compared and discussed. With the results, a comprehensive empirical relationship is proposed to determine the lateral displacements of the mid‐rise moment‐resisting building frames under earthquake and the influence of soil–structure interaction. Copyright © 2012 John Wiley & Sons, Ltd.     

An experimental study on the performance and emission characteristics of a CI engine fuelled with Jatropha biodiesel and its blends with diesel

The performance and emission characteristics of a compression ignition engine using mixture of jatropha biodiesel and mineral diesel have been experimentally investigated. It is observed that brake specific fuel consumption increases with higher percentage of biodiesel in the blends. Brake thermal efficiency decreases with the increased percentage of biodiesel in the blends. The maximum efficiency is found to be 29.6% with pure diesel and 21.2% with pure biodiesel. Carbon mono-oxide and hydrocarbon emissions are improved with the addition of biodiesel to diesel. NO_x emission is found to be increased with pure biodiesel by 24% compared to mineral diesel.     

A method for detection and classification of events in neural activity

We present a method for the real time prediction of punctuate events in neural activity, based on the time-frequency spectrum of the signal, applicable both to continuous processes like local field potentials (LFPs) as well as to spike trains. We test it on recordings of LFP and spiking activity acquired previously from the lateral intraparietal area (LIP) of macaque monkeys performing a memory-saccade task. In contrast to earlier work, where trials with known start times were classified, our method detects and classifies trials directly from the data. It provides a means to quantitatively compare and contrast the content of LFP signals and spike trains: we find that the detector performance based on the LFP matches the performance based on spike rates. The method should find application in the development of neural prosthetics based on the LFP signal. Our approach uses a new feature vector, which we call the 2d cepstrum.     

Motion control analysis of a parallel robot assisted minimally invasive surgery/microsurgery system (PRAMiSS)

This paper presents motion control architectures for a parallel robot assisted minimally invasive surgery/microsurgery system (PRAMiSS) that enable it to achieve milli/micro-manipulations under the constraint of moving through a fixed penetration point or so-called remote centre-of-motion (RCM) point without any mechanical constraint. Two control structures suitable for minimally invasive surgery operations with submillimeter accuracy and for minimally invasive microsurgery operations with the desired accuracy in micron range are proposed. The control algorithm also applies orientation constraints preventing the tip from orienting around the instrument axis due to the robot movements as well as a minimum displacement constraint to minimise the movements of the parallel micropositioning robot. Experiments were performed and the results are analysed in this paper to verify accuracy and effectiveness of the proposed control algorithm for both cases of minimally invasive surgery and microsurgery operations. The experimental results present good accuracy and performance of the control algorithm. The numerical modelling and graphical simulations were also carried out and the results are also provided that demonstrate the correlation between the experimental results and physical responses.     

Spatio-temporal object relationships in image sequences using adjacency matrices

In this work, we bring together object tracking and digital watermarking to solve the spatio-temporal object adjacency problem in image sequences. Spatio-temporal relationships are established by embedding objects with unique digital watermarks and then by propagating the watermark frame by frame. Watermark propagation is accomplished by an existing object tracking module so that a tracked object acquires its watermark from the correspondences established by the object tracker. The spatio-temporally marked image sequences can then be searched to establish spatial and temporal adjacency among objects without using traditional spatio-temporal graphs. Borrowing from graph theory, we construct binary adjacency matrices among tracked objects and develop interpretation rules to establish a track history for each object. Track history can be used to determine the arrival of new objects in frames or the changing of spatial and temporal positions of objects with respect to each other as they move through time and space.