Publications (135) View all
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Article: Proofs of the Technical Results Justifying an Algorithm for Collision Avoidance in Dynamic Environments with Moving and Deforming Obstacles
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ABSTRACT: This text presents the proofs of the technical facts underlying theoretical justification of the convergence and performance of the novel algorithm for reactive navigation of differential drive wheeled robots in dynamic uncertain environments. The algorithm restricts neither the natures nor the motions of the obstacles, they need not be rigid but conversely may deform. It does not consume data about the velocities, shapes, sizes, or orientations of the obstacles, and does not need a map of the environment or recognition of individual obstacles. The only information about the scene is the current distance to the nearest obstacle.04/2013; -
Article: Developments in control systems for rotary left ventricular assist devices for heart failure patients: a review.
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ABSTRACT: From the moment of creation to the moment of death, the heart works tirelessly to circulate blood, being a critical organ to sustain life. As a non-stopping pumping machine, it operates continuously to pump blood through our bodies to supply all cells with oxygen and necessary nutrients. When the heart fails, the supplement of blood to the body's organs to meet metabolic demands will deteriorate. The treatment of the participating causes is the ideal approach to treat heart failure (HF). As this often cannot be done effectively, the medical management of HF is a difficult challenge. Implantable rotary blood pumps (IRBPs) have the potential to become a viable long-term treatment option for bridging to heart transplantation or destination therapy. This increases the potential for the patients to leave the hospital and resume normal lives. Control of IRBPs is one of the most important design goals in providing long-term alternative treatment for HF patients. Over the years, many control algorithms including invasive and non-invasive techniques have been developed in the hope of physiologically and adaptively controlling left ventricular assist devices and thus avoiding such undesired pumping states as left ventricular collapse caused by suction. In this paper, we aim to provide a comprehensive review of the developments of control systems and techniques that have been applied to control IRBPs.Physiological Measurement 12/2012; 34(1):R1-R27. · 1.68 Impact Factor -
Article: Estimation of oxygen consumption during cycling and rowing.
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ABSTRACT: The aim of this paper is to develop estimator that can predict oxygen consumption (V(O2)) during cycling and rowing exercises, by using non-invasive and easily measurable quantities such as heart rate (HR), respiratory rate (RespR) and frequency of exercising activity. The frequency of exercise is quantified as a universal measure of exercise intensity and is known as Exercise Rate (ER). This ER is responsible for deviation in V(O2) (ΔV(O2)), HR (ΔHR), and RespR (ΔRespR) from their respective baseline measurements during exercise. Therefore, ΔV(O2) can be estimated from Δ, ΔRespR and ER. The resting measured of V(O2) is referred as V(O2rest); this is computed from the physical fitness of an individual. The Hammerstein model is adopted for the estimation of ΔV(O2). Results in this study demonstrate that the developed estimators for each type of exercise are capable of estimating V(O2) by adding up V(O2rest) and ΔV(O2) at various intensities during cycling and rowing.Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 08/2012; 2012:711-4. -
Article: Self-deployment of mobile robotic sensor networks for multilevel barrier coverage
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ABSTRACT: c1 Corresponding author. E-mail: t.cheng@ieee.orgRobotica 06/2012; 30(04):661 - 669. · 1.03 Impact Factor -
Article: Recent advances in the monitoring and control of haemodynamic variables during haemodialysis: a review.
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ABSTRACT: The human body possesses a unique set of organs that are responsible for providing homeostatic balance to the body's fluids. Of these, the kidneys regulate fluid and electrolyte balance in order to maintain the intracellular and extracellular fluid volumes and ion composition within tight limits. When kidneys fail to function normally, fluid is retained and several ions and solutes accumulate. The consequences may be life threatening. Many kidney failure patients rely on haemodialysis (HD) as a life sustaining therapy to remove the waste products and excess fluid from the circulating blood. HD is based on the principle of diffusion of solutes and ultrafiltration of fluid across a semi-permeable membrane. Fluid removal during HD results in relative hypovolaemia during which the stability of a patient relies on compensatory mechanisms to maintain blood pressure (BP). The major compensatory mechanisms include sympathetic nervous system activation of peripheral vasoconstriction together with modest heart rate acceleration to ensure the haemodynamic stability of the patient. Over the years, many monitoring tools have been developed in the hope of predicting intra-dialytic hypotensive episodes. Similarly many methods have been utilized to prevent dialysis-induced complications: ultrafiltration and dialysate sodium profiling, varying ultrafiltration based on frequent BP measurements, etc. This paper provides a comprehensive review of those monitoring and control tools. It starts with a brief introduction to human kidneys and dialysis for non-specialized readers. The paper then reviews the monitoring tools that have been applied to assess the physiological response of patients during HD. This is followed by control techniques used to prevent dialysis-induced complications.Physiological Measurement 12/2011; 33(1):R1-R31. · 1.68 Impact Factor
