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Estudio del efecto Doppler utilizando teléfonos inteligentes
Get PDFEn este artículo estudiamos cuantitativamente las características básicas del efecto Doppler usando un péndulo cuyo bulbo está constituido por dos teléfonos inteligentes (smartphones). Uno de los teléfonos se usa para la medición de la velocidad angular y la emisión de una señal sonora de una frecuencia fija (monocromática) y el otro teléfono se emplea para grabar la señal de audio desde un sistema solidario al emisor. Un micrófono fijo, en el lugar más bajo de la trayectoria del péndulo y conectado a un ordenador o PC, graba la señal sonora desde un sistema de referencia fijo al laboratorio. De este modo podemos comparar las señales de audio, medidas por dos observadores, uno en reposo y el otro en movimiento respecto de la fuente, simultáneamente. Se desarrolla un modelo teórico sencillo que permite explicar los datos observados. El experimento es de muy bajo costo, conceptualmente simple y permite mostrar algunos aspectos de la relatividad de medición en un laboratorio de enseñanza o en el hoga
Detection of follicles in ultrasound videos of bovine ovaries
No full text21st Iberoamerican Congress, CIARP 2016, Lima, Peru, 8–11, nov. 2016,Ultrasound imaging is a veterinarian standard procedure for the monitoring of ovarian structures in cattle. Recent studies, suggest that the number of antral follicles can give a cue of the future fertility of a specimen. Therefore, there has been a growing interest in counting the number of antral follicles at early stages in life. In the most typical procedure, the operator performs a trans-rectal ultrasound scan and counts the follicles on the live video that is seen in the ultrasound machine. This is a challenging task and requires highly trained experts that can reliably detect and count the follicles in a quick sweep of a few seconds. This work presents the integration of several signal processing techniques to the problem of automatically detecting follicles in ultrasound videos of bovine cattle ovaries. The approach starts from an ultrasound video that traverses the ovary from end to end. Putative follicle regions are detected on each frame with a cascade of boosted classifiers. In order to impose temporal coherence, the detections are tracked across the frames with multiple Kalman filters. The tracks are analyzed to separate follicle detections from other false detections. The method is tested on a phantom dataset of ovaries in gelatin with dissection ground truth. Results are promising and encourage further extension to in-vivo ultrasound videos
High-frequency resonant overvoltages in transformer regulating winding caused by ground fault initiation on feeding cable
No full textTransformer terminal equivalents obtained via admittance measurements are suitable for simulating high-frequency transient interaction between the transformer and the network. This paper augments the terminal equivalent approach with a measurement-based voltage transfer function model which permits calculation of voltages at internal points in the regulating winding. The approach is demonstrated for a single-phase three-winding transformer with its tap setting in the middle position. Three internal points in the regulating winding are included that represent the mid-point and the two extreme ends. The terminal equivalent modeling makes use of additional common-mode measurements to avoid error magnifications to result from the ungrounded tertiary winding. The final model is used in a time domain simulation where ground-fault initiation results in a resonant voltage build-up in the winding. It is shown that that the peak value of the resonant overvoltage can be higher than during the lightning impulse test, with unfavorable network conditions. Additional measurements show that the selected tap position affects the terminal behavior of the transformer, changing the frequency and peak value of the lower resonance point in the voltage transfer between winding
Total knee replacement evaluation with Dynamic CINARTRO Method
Get PDFVideofluoroscopy is used to evaluate the movement of the knee. The use of CINARTRO is here extended to Total Knee Replacement follow up, after incipient use in Anterior Cruciate Ligament repair. Tibial Femoral Contact Point (TFCP)
migration is smaller (42%) in prosthetic knees with respect to normal knees (55%). Considering flexion-extension stages
separately, the TFCP migration at full extension has a greater value (64%) than at mid extension and flexion (50% & 54%). The same behaviour is also observed for prosthetic knees, but all values reduced: a high of 50% at extension follows 37% & 41%. This can be interpreted as a prosthetic restored near-physiological behaviour
Construction of a transceiver prototype based on free space optics
Get PDFActualmente se observa un incremento en el uso de enlaces basados en óptica de espacio libre (FSO) como respuesta a la siempre creciente demanda de aplicaciones inalámbricas. Para contribuir al desarrollo de esta tecnología es importante tener un prototipo básico o banco de pruebas sobre el cual trabajar. En este trabajo se presenta la construcción de un transceptor básico basado en FSO. Este tiene interfaces Ethernet y logra una tasa de datos de 10 Mbps en un rango probado de 25 m. Rangos mayores pueden lograrse mejorando los lentes utilizados (lupas domésticas). Este primer prototipo permite trabajar en mejoras para convertirlo en un dispositivo comercial y también ganar conocimiento sobre esta tecnología a los efectos de evaluarla como alternativa de enlace inalámbrico entre satélites. Ambas líneas de investigación fueron iniciadas en el Departamento de Telecomunicaciones del Instituto de Ingeniería Eléctrica al finalizar la construcción de este prototipo.An increase in the use of Free Space Optics (FSO) links is observed as a response to the always growing demand of wireless applications. To contribute in the development of this technology it is important to have a basic prototype or testbed availableto implement solutions. In this work it is presented the construction of a basic FSO based transceiver. This one has Ethernet interfaces and achieves a throughput of 10 Mbps in a tested range of 25 m. A longer range is achievable by improving the used lenses (household loupes). This first prototype allows to improving this deviceforcommercial purposesand also to gain knowledge about this technology to evaluatethe device as a wireless link alternative between satellites. Both of thisresearch lines were started afterthe implementationof this first prototype in the Telecommunication Department of the Electrical Engineering Institut
Multi-resource allocation : analysis of a paid spectrum sharing approach based on fluid models
Get PDFNowadays industrial and academic communities are focusing much of their efforts to define the main characteristics of 5G. Cognitive Radio, offering the possibility to significantly increase the spectrum efficiency, will play a key role in the whole range of IoT communications (one of the use cases of 5G networks). While Cognitive Radio is one of the most discussed topics in contemporary spectrum management, there are still many issues and challenges to be solved, even more when we think about large networks. In this context, one of the main question that motivates this work is: how to encourage the spectrum sharing behavior of primary users (PUs)? With this in mind, we study a paid-sharing approach where secondary users (SUs) pay for spectrum utilization. We assume a preemptive system where PUs have strict priority over SUs, and the affected SUs will then be reimbursed, implying some cost for the PUs service provider. This paper bears on the analysis of the behavior of the system where the number of users is arbitrary large and an admission control policy over SUs is applied. We develop a computationally efficient methodology to find an accurate estimation of the optimal admission control boundary based on fluid limits
Distributed generation and demand response effects on the distribution network planning
Get PDFTrabajo presentado a EEE PES TransmissionDistribution Conference and Exhibition, Latin America (TD-LA), Lima, Perú,18-21 set., 2018.This paper studies the possible benefits/overcharges for a Distribution Network Operator (DNO) in the process of Planning the Distribution Network, when Distributed Generation (DG), and/or Demand Response (DR) policies are incorporated in the Distribution network. The results obtained for the design of the new grid with this participation are incorporated into the network planning process with different types of DG power plants and DR in their demand nodes, compared with the base case of demand obtained in the case of a network without changes in their consumption patterns neither DG incorporation. For the planning process of the new network in either cases, the classic Distribution Network Planning methodology was used, which is based on the classic economic theory of Minimum Total Cost (MTC) through which the Investment Plan of the Distribution Network of the Electrical Distribution Company is drawn up. The solutions obtained guarantee the supply of the power and energy demand of its customers at all times (all scenarios), minimizing the total cost equation and complying with the physical design constraints during the network planning horizon of 20 years. A genetic algorithm (GA) was used to search for the optimal solution (minim total cost) in a technical-economic point of view of the electricity network. Keywords—Distribution Network Planning, Distributed Generation, Demand Response, Technical Losses, Economic Evaluation
The jamming constant of uniform random graphs
Get PDFArtículo publicado en Stochastic Processes and their Applications, v.127, no. 7, 2017, pp. 2138-2178By constructing jointly a random graph and an associated exploration process, we define the dynamics of a “parking process” on a class of uniform random graphs as a measure-valued Markov process, representing the empirical degree distribution of non-explored nodes. We then establish a functional law of large numbers for this process as the number of vertices grows to infinity, allowing us to assess the jamming constant of the considered random graphs, i.e. the size of the maximal independent set discovered by the exploration algorithm. This technique, which can be applied to any uniform random graph with a given–possibly unbounded–degree distribution, can be seen as a generalization in the space of measures, of the differential equation method introduced by Wormal
Scaling limits and generic bounds for exploration processes
Get PDFArtículo publicado en Journal of Statistical Physics, v.169, 2017, pp. 989–1018We consider exploration algorithms of the random sequential adsorption type both for homogeneous random graphs and random geometric graphs based on spatial Poisson processes. At each step, a vertex of the graph becomes active and its neighboring nodes become blocked. Given an initial number of vertices N growing to infinity, we study statistical properties of the proportion of explored (active or blocked) nodes in time using scaling limits. We obtain exact limits for homogeneous graphs and prove an explicit central limit theorem for the final proportion of active nodes, known as the jamming constant, through a diffusion approximation for the exploration process which can be described as a unidimensional process. We then focus on bounding the trajectories of such exploration processes on random geometric graphs, i.e., random sequential adsorption. As opposed to exploration processes on homogeneous random graphs, these do not allow for such a dimensional reduction. Instead we derive a fundamental relationship between the number of explored nodes and the discovered volume in the spatial process, and we obtain generic bounds for the fluid limit and jamming constant: bounds that are independent of the dimension of space and the detailed shape of the volume associated to the discovered node. Lastly, using coupling techinques, we give trajectorial interpretations of the generic bounds. Keywords : Random sequential adsorption, Scaling limits, Random graph
Convenio específico entre la Universidad de la República. Facultad de Humanidades y Ciencias de la Educación y el Instituto Gerardo Cuesta-León Duarte del Plenario Intersindical de Trabajadores.Convención Nacional de Trabajadores.PIT-CNT
No full textIndentificación, análisis, diseño y ejecución de distintas acciones de asistencia técnica, investigación y enseñanza por parte de la Cátedra Unesco EPJA, ubicada en el Instituto de Educación de FHCE, a realizar conjuntamente con el equipo de Formación del Instituto Cuesta Duarte del PIT-CN