Analysis and design of a thrombectomy device by using simulation techniques

Purpose: In this work, we present the analysis, design and optimization of one experimental device recently developed in the UK, called the 'GP' Thrombus Aspiration Device (GPTAD). This device has been designed to remove blood clots without the need to make contact with the clot itself thereby potentially reducing the risk of problems such as downstream embolisation. Method: To obtain the minimum pressure necessary to extract the clot and to optimize the device, we have simulated the performance of the GPTAD analysing the resistances, compliances and inertances effects. We model a range of diameters for the GPTAD considering different forces of adhesion of the blood clot to the artery wall, and different lengths of blood clot. In each case we determine the optimum pressure required to extract the blood clot from the artery using the GPTAD, which is attached at its proximal end to a suction pump. Result: We then compare the results of our mathematical modelling to measurements made in laboratory using plastic tube models of arteries of comparable diameter. We use abattoir porcine blood clots that are extracted using the GPTAD. The suction pressures required for such clot extraction in the plastic tube models compare favourably with those predicted by the mathematical modelling. Discussion & Conclusion: We conclude therefore that the mathematical modelling is a useful technique in predicting the performance of the GPTAD and may potentially be used in optimising the design of the device.

Analysis of pattern recognition techniques for in-air signature biometrics

As a result of advances in mobile technology, new services which benefit from the ubiquity of these devices are appearing. Some of these services require the identification of the subject since they may access private user information. In this paper, we propose to identify each user by drawing his/her handwritten signature in the air (in-airsignature). In order to assess the feasibility of an in-airsignature as a biometric feature, we have analysed the performance of several well-known patternrecognitiontechniques—Hidden Markov Models, Bayes classifiers and dynamic time warping—to cope with this problem. Each technique has been tested in the identification of the signatures of 96 individuals. Furthermore, the robustness of each method against spoofing attacks has also been analysed using six impostors who attempted to emulate every signature. The best results in both experiments have been reached by using a technique based on dynamic time warping which carries out the recognition by calculating distances to an average template extracted from several training instances. Finally, a permanence analysis has been carried out in order to assess the stability of in-airsignature over time.

Analysis of pattern recognition and dimensionality reduction techniques for odor biometrics

In this paper, we analyze the performance of several well-known pattern recognition and dimensionality reduction techniques when applied to mass-spectrometry data for odor biometric identification. Motivated by the successful results of previous works capturing the odor from other parts of the body, this work attempts to evaluate the feasibility of identifying people by the odor emanated from the hands. By formulating this task according to a machine learning scheme, the problem is identified with a small-sample-size supervised classification problem in which the input data is formed by mass spectrograms from the hand odor of 13 subjects captured in different sessions. The high dimensionality of the data makes it necessary to apply feature selection and extraction techniques together with a simple classifier in order to improve the generalization capabilities of the model. Our experimental results achieve recognition rates over 85% which reveals that there exists discriminatory information in the hand odor and points at body odor as a promising biometric identifier.

New developments in lycopene analysis by spectroscopic and chromatographic techniques, accompanied by mathematical modelling

Comunicación Oral sobre los resultados obtenidos en el estudio de las propiedades del lycopeno presente en el tomate como compuesto bioactivo. Se realizó la identificación y cuantificación por diferentes metodologías experimentales. Se muestran los resultados analíticos comapartivamente con distintas técnicas.

Usability analysis of authentication techniques

This document will be divided into two main parts. The first one will be the classification of the authentication techniques. We will search the main electronic databases for papers related to authentication techniques. We will then summarize the related papers and show what classifications they use for the authentication techniques. After all of the documents have been read and summarized we will analyse them and group the authentication techniques into the classifications found. For the second part of the document we will focus on the study of usability attributes in the authentication techniques. This to know how authentications techniques compare to one another based on their usability attributes. We will search the main electronic databases for papers related to the usability attributes of authentication techniques based on the usability definition of ISO/IEC 25010 (SQuaRE) and its attributes. We will then summarize the related papers and show what authentication methods they describe and which usability attributes they measure. After all of the documents have been read and summarized we will analyse them depending on their usability attribute. At the end we will elaborate those results to show which authentication techniques have better usability in terms of a specific usability attribute. This will help practitioners who are interested in using authentication methods but want or need to focus on a specific usability attribute. They will be able to use this as a guide to help them chose the best option that fits their purpose.

Comparative analysis of measurement techniques of the sound absorption coefficient of a material

Las tendencias actuales apuntan al desarrollo de nuevos materiales económicos y ecológicos con óptimas propiedades mecánicas, acústicas y térmicas. En la caracterización acústica del material es habitual medir su coeficiente de absorción sonora. Las dos técnicas usuales de medida de este parámetro son en cámara reverberante y en tubo de Kundt. No obstante, existen técnicas de medida “in situ” del coeficiente de absorción que permiten una comprobación del comportamiento real en la forma definitiva de colocación del material. En este trabajo se presenta un estudio comparativo del coeficiente de absorción sonora medido en un material usando distintas técnicas de medida.