Aprimoramento de um baropodômetro eletrônico e análise de estabiliometria em voluntários com escoliose

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A Low Power CMOS Voltage Regulator for a Wireless Blood Pressure Biosensor

This paper describes a CMOS implementation of a linear voltage regulator (LVR) used to power up implanted physiological signal systems, as it is the case of a wireless blood pressure biosensor. The topology is based on a classical structure of a linear low-dropout regulator. The circuit is powered up from an RF link, thus characterizing a passive radio frequency identification (RFID) tag. The LVR was designed to meet important features such as low power consumption and small silicon area, without the need for any external discrete components. The low power operation represents an essential condition to avoid a high-energy RF link, thus minimizing the transmitted power and therefore minimizing the thermal effects on the patient's tissues. The project was implemented in a 0.35-mu m CMOS process, and the prototypes were tested to validate the overall performance. The LVR output is regulated at 1 V and supplies a maximum load current of 0.5 mA at 37 degrees C. The load regulation is 13 mV/mA, and the line regulation is 39 mV/V. The LVR total power consumption is 1.2 mW.

A New Method of Current Switching for Linear Wide-Range Measurement Systems

This new and general method here called overflow current switching allows a fast, continuous, and smooth transition between scales in wide-range current measurement systems, like electrometers. This is achieved, using a hydraulic analogy, by diverting only the overflow current, such that no slow element is forced to change its state during the switching. As a result, this approach practically eliminates the long dead time in low-current (picoamperes) switching. Similar to a logarithmic scale, a composition of n adjacent linear scales, like a segmented ruler, measures the current. The use of a linear wide-range system based on this technique assures fast and continuous measurement in the entire range, without blind regions during transitions and still holding suitable accuracy for many applications. A full mathematical development of the method is given. Several computer realistic simulations demonstrated the viability of the technique.

Formalizing languages for service oriented computing

Service Oriented Computing is a new programming paradigm for addressing distributed system design issues. Services are autonomous computational entities which can be dynamically discovered and composed in order to form more complex systems able to achieve different kinds of task. E-government, e-business and e-science are some examples of the IT areas where Service Oriented Computing will be exploited in the next years. At present, the most credited Service Oriented Computing technology is that of Web Services, whose specifications are enriched day by day by industrial consortia without following a precise and rigorous approach. This PhD thesis aims, on the one hand, at modelling Service Oriented Computing in a formal way in order to precisely define the main concepts it is based upon and, on the other hand, at defining a new approach, called bipolar approach, for addressing system design issues by synergically exploiting choreography and orchestration languages related by means of a mathematical relation called conformance. Choreography allows us to describe systems of services from a global view point whereas orchestration supplies a means for addressing such an issue from a local perspective. In this work we present SOCK, a process algebra based language inspired by the Web Service orchestration language WS-BPEL which catches the essentials of Service Oriented Computing. From the definition of SOCK we will able to define a general model for dealing with Service Oriented Computing where services and systems of services are related to the design of finite state automata and process algebra concurrent systems, respectively. Furthermore, we introduce a formal language for dealing with choreography. Such a language is equipped with a formal semantics and it forms, together with a subset of the SOCK calculus, the bipolar framework. Finally, we present JOLIE which is a Java implentation of a subset of the SOCK calculus and it is part of the bipolar framework we intend to promote.

Substructuring approache in state space models for dynamic system parameters identification

In the recent decade, the request for structural health monitoring expertise increased exponentially in the United States. The aging issues that most of the transportation structures are experiencing can put in serious jeopardy the economic system of a region as well as of a country. At the same time, the monitoring of structures is a central topic of discussion in Europe, where the preservation of historical buildings has been addressed over the last four centuries. More recently, various concerns arose about security performance of civil structures after tragic events such the 9/11 or the 2011 Japan earthquake: engineers looks for a design able to resist exceptional loadings due to earthquakes, hurricanes and terrorist attacks. After events of such a kind, the assessment of the remaining life of the structure is at least as important as the initial performance design. Consequently, it appears very clear that the introduction of reliable and accessible damage assessment techniques is crucial for the localization of issues and for a correct and immediate rehabilitation. The System Identification is a branch of the more general Control Theory. In Civil Engineering, this field addresses the techniques needed to find mechanical characteristics as the stiffness or the mass starting from the signals captured by sensors. The objective of the Dynamic Structural Identification (DSI) is to define, starting from experimental measurements, the modal fundamental parameters of a generic structure in order to characterize, via a mathematical model, the dynamic behavior. The knowledge of these parameters is helpful in the Model Updating procedure, that permits to define corrected theoretical models through experimental validation. The main aim of this technique is to minimize the differences between the theoretical model results and in situ measurements of dynamic data. Therefore, the new model becomes a very effective control practice when it comes to rehabilitation of structures or damage assessment. The instrumentation of a whole structure is an unfeasible procedure sometimes because of the high cost involved or, sometimes, because it’s not possible to physically reach each point of the structure. Therefore, numerous scholars have been trying to address this problem. In general two are the main involved methods. Since the limited number of sensors, in a first case, it’s possible to gather time histories only for some locations, then to move the instruments to another location and replay the procedure. Otherwise, if the number of sensors is enough and the structure does not present a complicate geometry, it’s usually sufficient to detect only the principal first modes. This two problems are well presented in the works of Balsamo [1] for the application to a simple system and Jun [2] for the analysis of system with a limited number of sensors. Once the system identification has been carried, it is possible to access the actual system characteristics. A frequent practice is to create an updated FEM model and assess whether the structure fulfills or not the requested functions. Once again the objective of this work is to present a general methodology to analyze big structure using a limited number of instrumentation and at the same time, obtaining the most information about an identified structure without recalling methodologies of difficult interpretation. A general framework of the state space identification procedure via OKID/ERA algorithm is developed and implemented in Matlab. Then, some simple examples are proposed to highlight the principal characteristics and advantage of this methodology. A new algebraic manipulation for a prolific use of substructuring results is developed and implemented.

Fluidodinamica biomedica computazionale del flusso sanguigno in presenza di affezioni strumentali e/o patologiche

La tesi di Dottorato studia il flusso sanguigno tramite un codice agli elementi finiti (COMSOL Multiphysics). Nell’arteria è presente un catetere Doppler (in posizione concentrica o decentrata rispetto all’asse di simmetria) o di stenosi di varia forma ed estensione. Le arterie sono solidi cilindrici rigidi, elastici o iperelastici. Le arterie hanno diametri di 6 mm, 5 mm, 4 mm e 2 mm. Il flusso ematico è in regime laminare stazionario e transitorio, ed il sangue è un fluido non-Newtoniano di Casson, modificato secondo la formulazione di Gonzales & Moraga. Le analisi numeriche sono realizzate in domini tridimensionali e bidimensionali, in quest’ultimo caso analizzando l’interazione fluido-strutturale. Nei casi tridimensionali, le arterie (simulazioni fluidodinamiche) sono infinitamente rigide: ricavato il campo di pressione si procede quindi all’analisi strutturale, per determinare le variazioni di sezione e la permanenza del disturbo sul flusso. La portata sanguigna è determinata nei casi tridimensionali con catetere individuando tre valori (massimo, minimo e medio); mentre per i casi 2D e tridimensionali con arterie stenotiche la legge di pressione riproduce l’impulso ematico. La mesh è triangolare (2D) o tetraedrica (3D), infittita alla parete ed a valle dell’ostacolo, per catturare le ricircolazioni. Alla tesi sono allegate due appendici, che studiano con codici CFD la trasmissione del calore in microcanali e l’ evaporazione di gocce d’acqua in sistemi non confinati. La fluidodinamica nei microcanali è analoga all’emodinamica nei capillari. Il metodo Euleriano-Lagrangiano (simulazioni dell’evaporazione) schematizza la natura mista del sangue. La parte inerente ai microcanali analizza il transitorio a seguito dell’applicazione di un flusso termico variabile nel tempo, variando velocità in ingresso e dimensioni del microcanale. L’indagine sull’evaporazione di gocce è un’analisi parametrica in 3D, che esamina il peso del singolo parametro (temperatura esterna, diametro iniziale, umidità relativa, velocità iniziale, coefficiente di diffusione) per individuare quello che influenza maggiormente il fenomeno.

Aging of nuclear power plant cables: in search of non-destructive diagnostic quantities

The safety systems of nuclear power plants rely on low-voltage power, instrumentation and control cables. Inside the containment area, cables operate in harsh environments, characterized by relatively high temperature and gamma-irradiation. As these cables are related to fundamental safety systems, they must be able to withstand unexpected accident conditions and, therefore, their condition assessment is of utmost importance as plants age and lifetime extensions are required. Nowadays, the integrity and functionality of these cables are monitored mainly through destructive test which requires specific laboratory. The investigation of electrical aging markers which can provide information about the state of the cable by non-destructive testing methods would improve significantly the present diagnostic techniques. This work has been made within the framework of the ADVANCE (Aging Diagnostic and Prognostics of Low-Voltage I\&C Cables) project, a FP7 European program. This Ph.D. thesis aims at studying the impact of aging on cable electrical parameters, in order to understand the evolution of the electrical properties associated with cable degradation. The identification of suitable aging markers requires the comparison of the electrical property variation with the physical/chemical degradation mechanisms of polymers for different insulating materials and compositions. The feasibility of non-destructive electrical condition monitoring techniques as potential substitutes for destructive methods will be finally discussed studying the correlation between electrical and mechanical properties. In this work, the electrical properties of cable insulators are monitored and characterized mainly by dielectric spectroscopy, polarization/depolarization current analysis and space charge distribution. Among these techniques, dielectric spectroscopy showed the most promising results; by means of dielectric spectroscopy it is possible to identify the frequency range where the properties are more sensitive to aging. In particular, the imaginary part of permittivity at high frequency, which is related to oxidation, has been identified as the most suitable aging marker based on electrical quantities.

Enhancing quality of service in software-defined networks

Resource management is of paramount importance in network scenarios and it is a long-standing and still open issue. Unfortunately, while technology and innovation continue to evolve, our network infrastructure system has been maintained almost in the same shape for decades and this phenomenon is known as “Internet ossification”. Software-Defined Networking (SDN) is an emerging paradigm in computer networking that allows a logically centralized software program to control the behavior of an entire network. This is done by decoupling the network control logic from the underlying physical routers and switches that forward traffic to the selected destination. One mechanism that allows the control plane to communicate with the data plane is OpenFlow. The network operators could write high-level control programs that specify the behavior of an entire network. Moreover, the centralized control makes it possible to define more specific and complex tasks that could involve many network functionalities, e.g., security, resource management and control, into a single framework. Nowadays, the explosive growth of real time applications that require stringent Quality of Service (QoS) guarantees, brings the network programmers to design network protocols that deliver certain performance guarantees. This thesis exploits the use of SDN in conjunction with OpenFlow to manage differentiating network services with an high QoS. Initially, we define a QoS Management and Orchestration architecture that allows us to manage the network in a modular way. Then, we provide a seamless integration between the architecture and the standard SDN paradigm following the separation between the control and data planes. This work is a first step towards the deployment of our proposal in the University of California, Los Angeles (UCLA) campus network with differentiating services and stringent QoS requirements. We also plan to exploit our solution to manage the handoff between different network technologies, e.g., Wi-Fi and WiMAX. Indeed, the model can be run with different parameters, depending on the communication protocol and can provide optimal results to be implemented on the campus network.

Schulterprothetik und Sport

In the last years life duration of shoulder prostheses could be prolonged through improvement of prosthesis quality, instrumentation and surgical techniques. After shoulder total arthroplasty, the patients show signifi cant reduction of pain and good functional mid and long term results. Indication to shoulder arthroplasty can be made by even younger and sportive active patients. Many sport activities remain possible after implantation of a shoulder prosthesis. A systematic rehabilitation is mandatory to yield optimal functional results. Intensity of sports activities should remain in relation with the preoperative status. Activities with total contact and high impaction strength should be avoided to extend the duration of life of the prosthesis.

Axial suspension test to assess pre-operative spinal flexibility in patients with adolescent idiopathic scoliosis.

INTRODUCTION An accurate description of the biomechanical behavior of the spine is crucial for the planning of scoliotic surgical correction as well as for the understanding of degenerative spine disorders. The current clinical assessments of spinal mechanics such as side-bending or fulcrum-bending tests rely on the displacement of the spine observed during motion of the patient. Since these tests focused solely on the spinal kinematics without considering mechanical loads, no quantification of the mechanical flexibility of the spine can be provided. METHODS A spinal suspension test (SST) has been developed to simultaneously monitor the force applied on the spine and the induced vertebral displacements. The system relies on cervical elevation of the patient and orthogonal radiographic images are used to measure the position of the vertebras. The system has been used to quantify the spinal flexibility on five AIS patients. RESULTS Based on the SST, the overall spinal flexibility varied between 0.3 °/Nm for the patient with the stiffer curve and 2 °/Nm for the less rigid curve. A linear correlation was observed between the overall spinal flexibility and the change in Cobb angle. In addition, the segmental flexibility calculated for five segments around the apex was 0.13 ± 0.07 °/Nm, which is similar to intra-operative stiffness measurements previously published. CONCLUSIONS In summary, the SST seems suitable to provide pre-operative information on the complex functional behavior and stiffness of spinal segments under physiological loading conditions. Such tools will become increasingly important in the future due to the ever-increasing complexity of the surgical instrumentation and procedures.

Physical oceanography during POSEIDON cruise POS264

RV POSEIDON cruise POS264 was carried out by the Institut für Meereskunde of the University of Hamburg and staff from the Niels Bohr Instituttet for Astronomi, Fysik og Geofysik of the University of Copenhagen also participated. The cruise had several objectives: - to educate undergraduate students in the handling of oceanographic instrumentation and in the collection and analysis of field data, - to map the cold overflow through the Faroe-Bank Channel from the Norwegian Sea into the Icelandic Basin and to study its short-time variability and - to quantify the contributions of the water masses which are involved in the mixing of the overflow plume with its ambient water. The planning and preparation of the cruise involved the participating students and was carried out during seminars, both at the Universities of Hamburg and Copenhagen. Following a review of the recent literature and an analysis of historical data the observational programme was designed. Hydrographic and current profiling stations were occupied along several sections crossing the overflow. The experiment was financed by the University of Hamburg. Temperature, salinity and dissolved oxygen data from CTD stations are presented. The temperature and salinity data were quality controlled and calibrated. Oxygen data are not calibrated as no oxygen samples were taken additionally during the cruise.

Power Measurement Methodology for FPGA Devices

The efficiency of power optimization tools depends on information on design power provided by the power estimation models. Power models targeting different power groups can enable fast identification of the most power consuming parts of design and their properties. The accuracy of these estimation models is highly dependent on the accuracy of the method used for their characterization. The highest precision is achieved by using physical onboard measurements. In this paper, we present a measurement methodology that is primarily aimed at calibrating and validating high-level dynamic power estimation models. The measurements have been carefully designed to enable the separation of the interconnect power from the logic power and the power of the clock circuitry, so that each of these power groups can be used for the corresponding model validation. The standard measurement uncertainty is lower than 2% of the measured value even with a very small number of repeated measurements. Additionally, the accuracy of a commercial low-level power estimation tool has been also assessed for comparison purposes. The results indicate that the tool is not suitable for power estimation of data path-oriented designs.

Considerations in Determining the Cost of Measurement Uncertainty Associated with Dimensional Tolerances Verification

The verification of compliance with a design specification in manufacturing requires the use of metrological instruments to check if the magnitude associated with the design specification is or not according with tolerance range. Such instrumentation and their use during the measurement process, has associated an uncertainty of measurement whose value must be related to the value of tolerance tested. Most papers dealing jointly tolerance and measurement uncertainties are mainly focused on the establishment of a relationship uncertainty-tolerance without paying much attention to the impact from the standpoint of process cost. This paper analyzes the cost-measurement uncertainty, considering uncertainty as a productive factor in the process outcome. This is done starting from a cost-tolerance model associated with the process. By means of this model the existence of a measurement uncertainty is calculated in quantitative terms of cost and its impact on the process is analyzed.

A novel context ontology to facilitate interoperation of semantic services in environments with wearable devices

The LifeWear-Mobilized Lifestyle with Wearables (Lifewear) project attempts to create Ambient Intelligence (AmI) ecosystems by composing personalized services based on the user information, environmental conditions and reasoning outputs. Two of the most important benefits over traditional environments are 1) take advantage of wearable devices to get user information in a nonintrusive way and 2) integrate this information with other intelligent services and environmental sensors. This paper proposes a new ontology composed by the integration of users and services information, for semantically representing this information. Using an Enterprise Service Bus, this ontology is integrated in a semantic middleware to provide context-aware personalized and semantically annotated services, with discovery, composition and orchestration tasks. We show how these services support a real scenario proposed in the Lifewear project.

Caracterización e instrumentación de sensores de ultrasonidos

El propósito de este proyecto de �fin de carrera es la caracterización e instrumentación de un sensor de ultrasonidos modelado por el tutor de este proyecto: Don César Briso Rodrí��guez. Una vez realizado el modelado de dicho sensor, simulando tanto sus caracter�í�sticas f�í�sicas, como sus caracterí��sticas eléctricas, se procede a la intrumentación y uso del mismo. La parte de intrumentaci�ón incluye tanto la electrónica que ser��á necesaria para la excitación del piezoeléctrico, en el modo de emisi�ón, como para la recepción de los pulsos el�éctricos generados por el sensor, como respuesta a los ecos recibidos, y su adecuación a niveles de señal correctos para la adquisici�ón, en el modo de escucha. Tras la adecuaci�ón de las señales para la adquisici�ón, éstas ser�án digitalizadas, tratadas y representadas por pantalla en un PC, a trav�es de una tarjeta de adquisición de datos por puerto USB encargada del muestreo de las señales de respuesta ya tratadas y su posterior enví��o al software de control y representaci�ón desarrollado en este proyecto. El entorno de usuario, el software de control de la tarjeta de adquisición y el software de tratamiento y representaci�ón se ha desarrollado con Visual Basic 2008 y las utilidades gr�áfi�cas de las librer��ías OpenGL. ABSTRACT The purpose of this project is to limit the characterization and implementation of an ultrasonic sensor modeled by Mr. C�ésar Briso Rodr��íguez. Once the sensor modeling by simulating physical characteristics and electrical characteristics, we proceed to the instrumentation and use. This section includes electronic instrumentation that would be necessary for the piezoelectric excitation in the emission mode and for receiving electrical pulses generated by the sensor in response to the received echoes, and matching signal levels right to acquire, in the reception mode. After the adjustment of the signals for the acquisition, these signals will be digitalized, processed and represented on the screen on a PC through a data acquisition card by USB port. Acquisition card is able to sample the response signals and transmit the samples to representation and control software developed in this project. The user interface, the acquisition card control software and processing and representation software has been developed with Visual Basic 2008 and OpenGL graphical libraries.