Do hybrid electric vehicles really work?

Peer Reviewe

Do hybrid electric vehicles really work?

Peer Reviewe

Development of tubular cardiovascular phantom system for pulse transit time simulation

This paper presents on the development of a tubular cardiovascular phantom system to simulate pulse transit time (PTT). The PTT defined as the delay time between two pulses in one cardiac cycle has been shown to be promising method for cuffless continuous blood pressure (BP) measurement. However most of the PTT measurement was performed on human subjects, thus giving a difficulty in validating sensor performance due to variability of BP. Therefore, a cardiovascular phantom system was proposed for simulate the PTT measurement. An electronic controlled module was developed to control pump operation for pulse generation. Plastic optical fibre (POF) sensors were used to measure the pulse signal on the flexible tube and the results were compared with an in-line pressure sensor. In this experiment, the delay time between two pulses were calculated offline using Matlab software and correlated with pulse pressure. The result demonstrate that the pulse delay time recorded by both sensors decreased with increase of pulse rate and pulse pressure. These results on the phantom study showed similar pattern to the human model, thus indicating that the system is able to simulate PTT for sensor validation purposes

Cuff-less continuous blood pressure monitoring system using pulse transit time techniques

This paper describes the development of a continuous cuff-less blood pressure system based on the pulse transit time (PTT) technique. In this study, PTT is defined by two different approaches denoted as PTT1 and PTT2. PTT1 is the time difference between the R-wave peak of the Electrocardiogram (ECG) and the peak of the Photoplethysmogram (PPG). PTT2 is the time difference between two peak PPG signals on same cardiac cycle at different positions on the body. The ECG is acquired on the chest using 3 lead electrodes and a reflection mode optical sensor is deployed on brachial artery and fingertip to monitor the PPGs. These data were synchronized using a National Instruments data acquisition card along with Matlab software for subsequent analysis. A wrist-type cuff-based blood pressure device was used to measure blood pressure on the right hand. Brachial blood pressure was measured on the upper left arm using oscillometric blood pressure monitor. Experiments were conducted by elevating the right hand at different position to investigate variability of PTT under the effects of hydrostatic pressure. Next the variability of PTT due to blood pressure changes during a Valsalva maneuver was investigated. The result shows that the PTT1 is inversely proportional to blood pressure in both experiments. Meanwhile, there is weak correlation between PTT2 and blood pressure measurement which suggests that by excluding the pre-ejection period (PEP) time in PTT calculation may reduce the accuracy of PTT for blood pressure measurement. In conclusion, PTT measurement between ECG and PPG signals has potential to be a reliable technique for cuff-less blood pressure measurement

Improving Grammaticality in Statistical Sentence Generation: Introducing a Dependency Spanning Tree Algorithm with an Argument Satisfaction Model

Abstract-like text summarisation requires a means of producing novel summary sentences. In order to improve the grammaticality of the generated sentence, we model a global (sentence) level syntactic structure. We couch statistical sentence generation as a spanning tree problem in order to search for the best dependency tree spanning a set of chosen words. We also introduce a new search algorithm for this task that models argument satisfaction to improve the linguistic validity of the generated tree. We treat the allocation of modifiers to heads as a weighted bipartite graph matching (or assignment) problem, a well studied problem in graph theory. Using BLEU to measure performance on a string regeneration task, we found an improvement, illustrating the benefit of the spanning tree approach armed with an argument satisfaction model.

Physicochemical characterisation of biosynthetic bacterial cellulose as a potential wound dressing material

The aim of this study was to characterise the physicochemical and biocompatibility properties of biosynthetic bacterial cellulose (BC) as a potential wound dressing material. The moisture content, water vapour transmission rate (WVTR), thermal stability, cyto- and haemo-compatibility of BC were investigated. Results indicated that the physicochemical properties of biosynthetic BC allow an optimum WVTR to be maintained for improved localised wound moisture levels, good thermal stability and excellent water imbibing capabilities. In vitro cytotoxicity and haemocompatibility confirmed the biocompatibility of BC and hence suitability of this material for further exploration into its’ application as a wound dressing material