Alicia Casals - Academia.edu (original) (raw)

Papers by Alicia Casals

Biomedical microdevices, 2016

Here we describe the design and evaluation of a fluidic device for the automatic processing of mi... more Here we describe the design and evaluation of a fluidic device for the automatic processing of microarrays, called microarray processing station or MPS. The microarray processing station once installed on a commercial microarrayer allows automating the washing, and drying steps, which are often performed manually. The substrate where the assay occurs remains on place during the microarray printing, incubation and processing steps, therefore the addressing of nL volumes of the distinct immunoassay reagents such as capture and detection antibodies and samples can be performed on the same coordinate of the substrate with a perfect alignment without requiring any additional mechanical or optical re-alignment methods. This allows the performance of independent immunoassays in a single microarray spot.

This paper proposes a new approach in the image analysis for autonomous navigation. The aim of th... more This paper proposes a new approach in the image analysis for autonomous navigation. The aim of the work is to choose the adequate resolution all along the image to get a good compromise between processing time and robustness. Since close and far areas of the scene are projected in the image with different resolution, our approach is addressed to sample

Journal of the Robotics Society of Japan, 2006

Background and Professional Career Industrial Engineering is a degree that provides a wide view o... more Background and Professional Career Industrial Engineering is a degree that provides a wide view of technology. The selection of a degree is usually not easy and my selection of Industrial Engineering was motivated by both, my interest in knowing how machines work, and for the wide range of applications and possible professional options of these studies, either in industry, in the services sector or in education. The launching of a new degree in Computer Science gave me the chance to initiate my professional career as a teacher in the new Faculty of Informatics and to participate in the creation of the research group in Robotics, an emerging area in the seventies. After a first phase working in industrial applications of robotics and computer vision, robotics evolved towards the services sector giving place to applications where vision, and perception in general, is essential to provide robots with more intelligent behaviors, and in this direction has progressed our research. 2. Current Research Areas of the Research Group The research group on Intelligent Robotics and Systems at UPC, GRINS, works mainly in areas of robotics requiring strong interaction with humans, that is, tele-*

Current computer and robot assisted surgery implies a planning and simulation process previous to... more Current computer and robot assisted surgery implies a planning and simulation process previous to an intervention. A problem that appears in surgery is the need to eventually change the operating strategy during the intervention, due to unforeseen situations that can appear, or to improve the program developed under some uncertainness. The work developed consists of a system that provides the means of reprogramming the robot trajectory constrains, without the need of technical assistance. The changes can be done by the own surgeon, through gestures and without requiring any specific device

IFMBE Proceedings, 2014

Stroke is a major cause of disability, usually causing hemiplegic damage on the motor abilities o... more Stroke is a major cause of disability, usually causing hemiplegic damage on the motor abilities of the patient. Stroke rehabilitation seeks restoring normal motion on the affected limb. However, 'normality' of movements is usually assessed by clinical and functional tests, without considering how the motor system responds to therapy. We hypothesized that electromyographic (EMG) recordings could provide useful information for evaluating the outcome of rehabilitation from a neuromuscular perspective. Four healthy subjects were asked to perform 14 different functional movements simulating the action of reaching over a table. Each movement was defined according to the starting and target positions that the subject had to connect using linear trajectories. Bipolar recordings of EMG signals were taken from biceps and triceps muscles, and spectral and temporal characteristics were extracted for each movement. Using pattern recognition techniques we found that only two EMG channels were sufficient to accurately determine the spatial characteristics of motor activity: movement direction, length and execution zone. Our results suggest that muscles may fire in a patterned way depending on the specific characteristics of the movement and that EMG signals may codify such detailed information. These findings may be of great value to quantitatively assess poststroke rehabilitation and to compare the neuromuscular activity of the affected and unaffected limbs, from a physiological perspective. Furthermore, disturbed movements could be characterized in terms of the muscle function to identify, which is the spatial characteristic that fails, e.g. movement direction, and guide personalized rehabilitation to enhance the training of such characteristic.

International Journal of System Dynamics Applications, 2014

Robotic rehabilitation is an emerging technology in the field of Neurorehabilitation, which aims ... more Robotic rehabilitation is an emerging technology in the field of Neurorehabilitation, which aims to achieve an effective patient recovery. This research focusses on the control strategy for an assistive exoskeleton aiming to reduce the effects of disturbances on planned trajectories during rehabilitation therapies. Disturbances are mostly caused by muscle synergies or by unpredictable actions produced by functional electrical stimulation. The effect of these disturbances can be either assistive or resistive forces depending on the patient's movement, which increase or decrease the speed of the affected joints by forcing the control unit to act consequently. In some therapies, like gait assistance, it is also essential to maintain synchronization between joint movements, to ensure a dynamic stability. A force control approach is used for all the joints individually, while two control methods are defined to act when disturbances are detected: Cartesian position control (Cartesian ...

Proceedings 2002 IEEE International Conference on Robotics and Automation (Cat. No.02CH37292)

ABSTRACT

Springer Tracts in Advanced Robotics, 2006

ABSTRACT New human machine interfaces are becoming more and more necessary in robotics applicatio... more ABSTRACT New human machine interfaces are becoming more and more necessary in robotics applications where the robot operates in close cooperation with a human, and one near to each other. Many of these applications require intuitive interaction systems since they are used by non robotic experts, thus the use of natural language based interfaces (either voice or gestures) are highly convenient. This research tackles the problem of interpreting the user arm and hand gestures as orders to the system, while the user is working close to the robot. The proposed human-machine interface looks for a compromise between classical interfaces and the hands free operation requirements.

Image and Vision Computing, 2001

... Permissions & Reprints. A new approach to outdoor scene description based on learning and... more ... Permissions & Reprints. A new approach to outdoor scene description based on learning and top-down segmentation. ... Abstract. This paper presents a new approach to outdoor scene description, by providing a methodology for labelling image objects in a top-down way. ...

2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2016

Estimation of the cardiac motion is very important in order to detect heart diseases. This work p... more Estimation of the cardiac motion is very important in order to detect heart diseases. This work presents a cardiac motion estimation approach using ultrafast ultrasound data. We optimize a variational framework which has the benefits of combining low-rank data representation with topology preservation. We show through the analysis of experimental results that this combination offers a radical reduction in computational time and noise while ensuring preservation of the anatomical structure of the heart under complex deformations. Although in this work we use the heart as a study case, our solution is promising to analyze other organs experiencing motion.

Proceedings of the 10th International Conference on Informatics in Control, Automation and Robotics, 2013

The use of pose-based features has demonstrated to be a promising approach for human motion recog... more The use of pose-based features has demonstrated to be a promising approach for human motion recognition. Encouraged by the results achieved, a new relational pose-based feature, Trisarea, based on geometric relationship between human joints, is proposed and analysed. This feature is defined as the area of the triangle formed by connecting three joints. The paper shows how the variation of a selected set of Trisarea features over time constitutes a descriptor of human motion. It also demonstrates how this motion descriptor based on Trisarea features can provide useful information in terms of human motion for its application to action recognition tasks.

Advances in Intelligent Systems and Computing, 2019

The growing need of technological assistance to provide support to people with special needs dema... more The growing need of technological assistance to provide support to people with special needs demands for systems more and more efficient and with better performances. With this aim, this work tries to advance in a multirobot platform that allows the coordinated control of different agents and other elements in the environment to achieve an autonomous behavior based on the user's needs or will. Therefore, this environment is structured according to the potentiality of each agent and elements of this environment and of the dynamic context, to generate the adequate actuation plans and the coordination of their execution.

Compensating physiological motion in the context of minimally invasive cardiac surgery ... more Compensating physiological motion in the context of minimally invasive cardiac surgery has become an attractive issue since it outperforms traditional cardiac procedures offering remarkable benefits. Owing to space restrictions, computer vision techniques have proven to be the most practical and suitable solution. However, the lack of robustness and efficiency of existing methods make physiological motion compensation an open and challenging problem. This work focusses on increasing robustness and efficiency via exploration of the classes of 1−and 2−regularized optimization, emphasizing the use of explicit regularization. Both approaches are based on natural features of the heart using intensity information. Results pointed out the 1−regularized optimization class as the best since it offered the shortest computational cost, the smallest average error and...

Biomedical Signal Processing and Control, 2019

Providing force feedback as relevant information in current Robot-Assisted Minimally Invasive Sur... more Providing force feedback as relevant information in current Robot-Assisted Minimally Invasive Surgery systems constitutes a technological challenge due to the constraints imposed by the surgical environment. In this context, Sensorless Force Estimation techniques represent a potential solution, enabling to sense the interaction forces between the surgical instruments and soft-tissues. Specifically, if visual feedback is available for observing soft-tissues' deformation, this feedback can be used to estimate the forces applied to these tissues. To this end, a force estimation model, based on Convolutional Neural Networks and Long-Short Term Memory networks, is proposed in this work. This model is designed to process both, the spatiotemporal information present in video sequences and the temporal structure of tool data (the surgical tool-tip trajectory and its grasping status). A series of analyses are carried out to reveal the advantages of the proposal and the challenges that remain for real applications. This research work focuses on two surgical task scenarios, referred to as pushing and pulling tissue. For these two scenarios, different input data modalities and their effect on the force estimation quality are investigated. These input data modalities are tool data, video sequences and a combination of both. The results suggest that the force estimation quality is better when both, the tool data and video sequences, are processed by the neural network model. Moreover, this study reveals the need for a loss function, designed to promote the modeling of smooth and sharp details found in force signals. Finally, the results show that the modeling of forces due to pulling tasks is more challenging than for the simplest pushing actions.

2016 IEEE International Conference on Fuzzy Systems (FUZZ-IEEE), 2016

Fuzzy theory was motivated by the need to create human-like solutions that allow representing vag... more Fuzzy theory was motivated by the need to create human-like solutions that allow representing vagueness and uncertainty that exist in the real-world. These capabilities have been recently further enhanced by deep learning since it allows converting complex relation between data into knowledge. In this paper, we present a novel Deep-Neuro-Fuzzy strategy for unsupervised estimation of the interaction forces in Robotic Assisted Minimally Invasive scenarios. In our approach, the capability of Neuro-Fuzzy systems for handling visual uncertainty, as well as the inherent imprecision of real physical problems, is reinforced by the advantages provided by Deep Learning methods. Experiments conducted in a realistic setting have demonstrated the superior performance of the proposed approach over existing alternatives. More precisely, our method increased the accuracy of the force estimation and compared favorably to existing state of the art approaches, offering a percentage of improvement that ranges from about 35% to 85%.

Advances in Intelligent Systems and Computing, 2015

A user intention based rehabilitation strategy for a lower-limb wearable robot is proposed and ev... more A user intention based rehabilitation strategy for a lower-limb wearable robot is proposed and evaluated. The control strategy, which involves monitoring the human-orthosis interaction torques, determines the gait initiation instant and modifies orthosis operation for gait assistance, when needed. Orthosis operation is classified as assistive or resistive in function of its evolution with respect to a normal gait pattern. The control algorithm relies on the adaptation of the joints' stiffness in function of their interaction torques and their deviation from the desired trajectories. An average of recorded gaits obtained from healthy subjects is used as reference input. The objective of this work is to develop a control strategy that can trigger the gait initiation from the user's intention and maintain the dynamic stability, using an efficient real-time stiffness adaptation for multiple joints, simultaneously maintaining their synchronization. The algorithm has been tested with five healthy subjects showing its efficient behavior in initiating the gait and maintaining the equilibrium while walking in presence of external forces. The work is performed as a preliminary study to assist patients suffering from incomplete Spinal cord injury and Stroke.

Uno de los principales objetivos de las terapias de rehabilitación del miembro superior asistidas... more Uno de los principales objetivos de las terapias de rehabilitación del miembro superior asistidas por robots es incrementar la recuperación funcional al finalizar la terapia y a su vez disminuir el tiempo de esta recuperación, promoviendo la neuroplasticidad en pacientes con problemas neuromusculares. En este sentido es importante que los exoesqueletos se adapten a los movimientos del paciente y no de al revés. Este artículo presenta un ortesis para la extremidad superior con servoadaptación dinámica para la articulación del codo con el objetivo de reducir las fuerzas de interacción causadas por el desalineamiento entre el robot y la extremidad superior. Se estudia además el grado de asistencia que se debe efectuar durante la terapia con el objetivo de promover la neuroplasticidad y que el paciente trabaje en la totalidad de sus capacidades optimizando así la recuperación. I. INTRODUCCIÓN L uso de sistemas robóticos en terapias de rehabilitación, ha significado un cambio importante en los protocolos de rehabilitación de los miembros superiores e inferiores, que se ha traducido en mejoras de los tiempos de ejecución de la terapia, de los tiempos de recuperación del paciente, ha incrementado la funcionalidad de los miembros afectados al final de la terapia y a contribuido a motivar al paciente durante el transcurso de esta; todo en comparación con terapias no robotizadas. Por otro lado el poder controlar la terapia a bajo nivel, es decir, teniendo un completo control de los parámetros cinemáticos y dinámicos aplicados sobre el miembro Manuscrito recibido en Junio 24, 2011. Este trabajo es financiado en

Human–Computer Interaction, 2015

The performance of interfaces is affected by human factors, which vary from one person to another... more The performance of interfaces is affected by human factors, which vary from one person to another, and by the inherent characteristics of the various devices involved. A set of techniques has been studied in order to improve the efficiency and efficacy of input interface devices. These techniques are based on the modification of the motor scaling factor, a transformation similar to the known Control-Display ratio (CD ratio). Operation time, the accuracy of the task and user workload are the indicators used in this work. By means of models based on the various human motor behaviors, the improvement of such indicators has been demonstrated. Using some common input interface devices, a number of experiments have been carried out to evaluate the presented methodology. The results show that the overall performance of input interfaces is significantly improved by applying such methodology.

Advances in Intelligent Systems and Computing, 2014

Heart motion compensation is a challenging problem within medical robotics and it is still consid... more Heart motion compensation is a challenging problem within medical robotics and it is still considered an open research area due to the lack of robustness. As it can be formulated as an energy minimization problem, an optimization technique is needed. The selection of an adequate method has a significant impact over the global solution. For this reason, a new methodology is presented here for solving heart motion compensation in which the central topic is oriented to increase robustness with the goal of achieving a balance between efficiency and efficacy. Particularly, genetic algorithms are used as optimization technique since they can be adapted to any real application, complex and oriented to work in real-time problems.