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by Keyword: Performance


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Aviles, A. I., Casals, A., (2014). Interpolation based deformation model for minimally invasive beating heart surgery IFMBE Proceedings XIII Mediterranean Conference on Medical and Biological Engineering and Computing 2013 (ed. Roa Romero, Laura M.), Springer International Publishing (London, UK) 41, 372-375

Heart motion compensation is a key issue in medical robotics due to the benefits that minimally invasive beating heart surgery offers over traditional cardiac surgery. Although different proposals have been presented, nowadays, there is not yet a suitable solution working in real clinical environments due to the lack of robustness of existing methods. The process of heart motion estimation required to produce the compensation actions can be tackled as a process of three iterative steps. The first based on generating a deformation model from the processing of a video sequence of the beating heart. The selection of a deformation model is crucial in the sense that it has to offer both valuable information and good computational performance. These characteristics are required when the reaction time has a significant repercussion over the system behavior, as in this case. This paper, presents a computational analysis of deformation model based on interpolation methods. In particular, wavelet and thin-plate splines are evaluated. The significance of this study relies on the fact that it is a reference starting point of reference for creating both a common framework and a robust solution. In addition, the obtained results will contribute to increase the robustness from the initial stage of the solution.

Keywords: Deformation model, Wavelets, Computer performance, Radial basis functions, Interpolation methods


Karpas, Z., Guamán, A. V., Pardo, A., Marco, S., (2013). Comparison of the performance of three ion mobility spectrometers for measurement of biogenic amines Analytica Chimica Acta 758, (3), 122-129

The performance of three different types of ion mobility spectrometer (IMS) devices: GDA2 with a radioactive ion source (Airsense, Germany), UV-IMS with a photo-ionization source (G.A.S. Germany) and VG-Test with a corona discharge source (3QBD, Israel) was studied. The gas-phase ion chemistry in the IMS devices affected the species formed and their measured reduced mobility values. The sensitivity and limit of detection for trimethylamine (TMA), putrescine and cadaverine were compared by continuous monitoring of a stream of air with a given concentration of the analyte and by measurement of headspace vapors of TMA in a sealed vial. Preprocessing of the mobility spectra and the effectiveness of multivariate curve resolution techniques (MCR-LASSO) improved the accuracy of the measurements by correcting baseline effects and adjusting for variations in drift time as well as enhancing the signal to noise ratio and deconvolution of the complex data matrix to their pure components. The limit of detection for measurement of the biogenic amines by the three IMS devices was between 0.1 and 1.2 ppm (for TMA with the VG-Test and GDA, respectively) and between 0.2 and 0.7 ppm for putrescine and cadaverine with all three devices. Considering the uncertainty in the LOD determination there is almost no statistically significant difference between the three devices although they differ in their operating temperature, ionization method, drift tube design and dopant chemistry. This finding may have general implications on the achievable performance of classic IMS devices.

Keywords: Biogenic amines, Comparison of performance, Ion mobility spectrometry, Sensitivity, Signal processing, Vapor concentration


Azevedo, S., Diéguez, L., Carvalho, P., Carneiro, J. O., Teixeira, V., Martínez, Elena, Samitier, J., (2012). Deposition of ITO thin films onto PMMA substrates for waveguide based biosensing devices Journal of Nano Research , 17, 75-83

Biosensors' research filed has clearly been changing towards the production of multifunctional and innovative design concepts to address the needs related with sensitivity and selectivity of the devices. More recently, waveguide biosensors, that do not require any label procedure to detect biomolecules adsorbed on its surface, have been pointed out as one of the most promising technologies for the production of biosensing devices with enhanced performance. Moreover the combination of optical and electrochemical measurements through the integration of transparent and conducting oxides in the multilayer structures can greatly enhance the biosensors' sensitivity. Furthermore, the integration of polymeric substrates may bring powerful advantages in comparison with silicon based ones. The biosensors will have a lower production costs being possible to disposable them after use ("one use sensor chip"). This research work represents a preliminary study about the influence of substrate temperature on the overall properties of ITO thin films deposited by DC magnetron sputtering onto 0,5 mm thick PMMA sheets.

Keywords: ITO thin films, PMMA sheets, Waveguide biosensing devices, Biosensing devices, Conducting oxides, Dc magnetron sputtering, Electrochemical measurements, Enhanced performance, Innovative design, ITO thin films, Multilayer structures, Overall properties, PMMA sheets, Polymeric substrate, Production cost, Sensor chips, Silicon-based, Substrate temperature, Biosensors, Deposition, Design, Film preparation, Optical multilayers, Thin films, Vapor deposition, Waveguides, Substrates


Hernansanz, A., Zerbato, D., Gasperotti, L., Scandola, M., Casals, A., Fiorini, P., (2012). Assessment of virtual fixtures for the development of basic skills in robotic surgery International Journal of Computer Assisted Radiology and Surgery CARS 2012 Computer Assisted Radiology and Surgery , Springer (Pisa, Italy) 7 (Supplement 1) - Surgical Modelling, Simulation and Education, S186-S188

Teleoperation, by adequately adapting computer interfaces, can benefit from the knowledge on human factors and psychomotor models in order to improve the effectiveness and efficiency in the execution of a task. While scaling is one of the performances frequently used in teleoperation tasks that require high precision, such as surgery, this article presents a scaling method that considers the system dynamics as well. The proposed dynamic scaling factor depends on the apparent position and velocity of the robot and targets. Such scaling improves the performance of teleoperation interfaces, thereby reducing user's workload.

Keywords: Human-robot interaction, Throughput, Scaling functions, Motor control performance


Muñoz, L. M., Casals, A., (2012). Dynamic scaling interface for assisted teleoperation IEEE International Conference on Robotics and Automation (ICRA) , IEEE (Minnesota, USA) , 4288-4293

Teleoperation, by adequately adapting computer interfaces, can benefit from the knowledge on human factors and psychomotor models in order to improve the effectiveness and efficiency in the execution of a task. While scaling is one of the performances frequently used in teleoperation tasks that require high precision, such as surgery, this article presents a scaling method that considers the system dynamics as well. The proposed dynamic scaling factor depends on the apparent position and velocity of the robot and targets. Such scaling improves the performance of teleoperation interfaces, thereby reducing user's workload.

Keywords: Human-robot interaction, Motor control performance, Scaling functions, Throughput


Chaparro, J.A., Giraldo, B.F., Caminal, P., Benito, S., (2012). Performance of respiratory pattern parameters in classifiers for predict weaning process Engineering in Medicine and Biology Society (EMBC) 34th Annual International Conference of the IEEE , IEEE (San Diego, USA) , 4349-4352

Weaning trials process of patients in intensive care units is a complex clinical procedure. 153 patients under extubation process (T-tube test) were studied: 94 patients with successful trials (group S), 38 patients who failed to maintain spontaneous breathing and were reconnected (group F), and 21 patients with successful test but that had to be reintubated before 48 hours (group R). The respiratory pattern of each patient was characterized through the following time series: inspiratory time (TI), expiratory time (TE), breathing cycle duration (TTot), tidal volume (VT), inspiratory fraction (TI/TTot), half inspired flow (VT/TI), and rapid shallow index (f/VT), where f is respiratory rate. Using techniques as autoregressive models (AR), autoregressive moving average models (ARMA) and autoregressive models with exogenous input (ARX), the most relevant parameters of the respiratory pattern were obtained. We proposed the evaluation of these parameters using classifiers as logistic regression (LR), linear discriminant analysis (LDA), support vector machines (SVM) and classification and regression tree (CART) to discriminate between patients from groups S, F and R. An accuracy of 93% (98% sensitivity and 82% specificity) has been obtained using CART classification.

Keywords: Accuracy, Indexes, Logistics, Regression tree analysis, Support vector machines, Time series analysis, Autoregressive moving average processes, Medical signal processing, Pattern classification, Pneumodynamics, Regression analysis, Sensitivity, Signal classification, Support vector machines, Time series, SVM, T-tube testing, Autoregressive models-with-exogenous input, Autoregressive moving average models, Breathing cycle duration, Classification-and-regression tree, Expiratory time, Extubation process, Half inspired flow, Inspiratory fraction, Inspiratory time, Intensive care units, Linear discriminant analysis, Logistic regression, Rapid shallow index, Respiratory pattern parameter performance, Sensitivity, Spontaneous breathing, Support vector machines, Tidal volume, Time 48 hr, Time series, Weaning process classifiers


Miguel Munoz, Luis, Casals, Alicia, Frigola, Manel, Amat, Josep, (2011). Motor-model-based dynamic scaling in human-computer interfaces IEEE Transactions on Systems Man and Cybernetics Part B-Cybernetics , 41, (2), 435-447

This paper presents a study on how the application of scaling techniques to an interface affects its performance. A progressive scaling factor based on the position and velocity of the cursor and the targets improves the efficiency of an interface, thereby reducing the user's workload. The study uses several human-motor models to interpret human intention and thus contribute to defining and adapting the scaling parameters to the execution of the task. Two techniques addressed to vary the control-display ratio are compared, and a new method for aiding in the task of steering is proposed.

Keywords: Performance, Movements


Farre, R., Navajas, D., (2009). Quality control: A necessary, but sometimes overlooked, tool for improving respiratory medicine European Respiratory Journal , 33, (4), 722-723

The importance of quality control in both general and respiratory medicine has increased in parallel with the complexity of healthcare provision. Only a few decades ago, the respiratory physician and/or scientist had a very limited number of diagnostic and therapeutic tools available and, moreover, medical practice was based almost exclusively on the personal interaction between doctor and patient. Consequently, at that time the quality of the respiratory healthcare depended entirely on the professional competence of the doctor. Although nowadays the relationship between physician and patient undoubtedly still lies at the heart of respiratory medical practice, the quality of the medical service received by the patient also depends on many other participants in a complex healthcare network: various medical specialists, lung function technicians, nurses, respiratory therapists, social workers and administrative staff. Accordingly, several quality control programmes are applied in order to avoid, or at least to reduce, errors in diagnosis, improper performance of procedures, errors in medication, and failure to supervise or monitor care or recognise complications associated with treatment

Keywords: Airway pressure devices, Clinical-trial, Standardization, Spirometry, Lung, Home, Ventilators, Publication, Performance, Technology


Diez, Pablo F., Laciar, Eric, Mut, Vicente, Avila, Enrique, Torres, Abel, (2008). A comparative study of the performance of different spectral estimation methods for classification of mental tasks IEEE Engineering in Medicine and Biology Society Conference Proceedings 30th Annual International Conference of the Ieee Engineering in Medicine and Biology Society (ed. IEEE), IEEE (Vancouver, Canada) 1-8, 1155-1158

In this paper we compare three different spectral estimation techniques for the classification of mental tasks. These techniques are the standard periodogram, the Welch periodogram and the Burg method, applied to electroencephalographic (EEG) signals. For each one of these methods we compute two parameters: the mean power and the root mean square (RMS), in various frequency bands. The classification of the mental tasks was conducted with a linear discriminate analysis. The Welch periodogram and the Burg method performed better than the standard periodogram. The use of the RMS allows better classification accuracy than the obtained with the power of EEG signals.

Keywords: Adult, Algorithms, Artificial Intelligence, Cognition, Electroencephalography, Female, Humans, Male, Pattern Recognition, Automated, Reproducibility of Results, Sensitivity and Specificity, Task Performance and Analysis, User-Computer Interface