A Probabilistic Approach to Computerized Tracking of Arterial Walls in Ultrasound Image Sequences

Tracking of arterial walls in ultrasound image sequences is useful for studying the dynamics of arteries. Manual delineation is prohibitively labour intensive and existing methods of computerized segmentation are limited in terms of applicability and availability. This paper presents a probabilistic approach to the computerized tracking of arterial walls that is effective and easy to implement. In the probabilistic approach, given a point B with a probability Pb of being in an arterial lumen of interest, the probability Pa that a neighbouring point A is also a part of the same lumen is proportional to Pb with a Gaussian fall in probability with increasing grayscale contrast between the two points. Efficacy of the probabilistic algorithm was evaluated by testing it on ultrasound images and image sequences of the carotid arteries and the abdominal aorta and various laboratory, ultrasound test objects. The results showed that the probabilistic algorithm produced robust and effective lumen segmentation in the majority of cases encountered. Comparison with a conventional region growing technique based on intensity thresholding with a running, regional intensity average identified the main benefits of the probabilistic approach as increased immunity to speckle noise within the arterial lumen and a reduced susceptibility to region overflowing at boundary imperfections

A Probabilistic Approach to Computerized Tracking of Arterial Walls in Ultrasound Image Sequences

Tracking of arterial walls in ultrasound image sequences is useful for studying the dynamics of arteries. Manual delineation is prohibitively labour intensive and existing methods of computerized segmentation are limited in terms of applicability and availability. This paper presents a probabilistic approach to the computerized tracking of arterial walls that is effective and easy to implement. In the probabilistic approach, given a point B with a probability Pb of being in an arterial lumen of interest, the probability Pa that a neighbouring point A is also a part of the same lumen is proportional to Pb with a Gaussian fall in probability with increasing grayscale contrast between the two points. Efficacy of the probabilistic algorithm was evaluated by testing it on ultrasound images and image sequences of the carotid arteries and the abdominal aorta and various laboratory, ultrasound test objects. The results showed that the probabilistic algorithm produced robust and effective lumen segmentation in the majority of cases encountered. Comparison with a conventional region growing technique based on intensity thresholding with a running, regional intensity average identified the main benefits of the probabilistic approach as increased immunity to speckle noise within the arterial lumen and a reduced susceptibility to region overflowing at boundary imperfections

Impacto económico y social de la recaudación e inversión del impuesto predial en el municipio pijiño del carmen, magdalena, en los años 2013 y 2014

El presente trabajo incluye un breve recorrido por la historia del impuesto predial en Colombia. Comienza en el siglo XX y llega hasta nuestros días, evidenciando la manera como se ha estructurado a lo largo del tiempo. Posteriormente se procede a realizar el estudio del marco constitucional y legal que regula el comportamiento del tributo, así como el análisis de la autonomía con que cuentan las entidades territoriales para disponer del derecho regulatorio y el cobro del mismo. En la línea que continúa este trabajo, se aborda el tema de los mecanismos legales que tienen las entidades territoriales para vincular el impuesto predial al ordenamiento jurídico local e incluirlo en los presupuestos municipales como un medio para sostener los gastos de funcionamiento y la inversión social. Esta autonomía les permite a los municipios organizar y direccionar los recursos públicos de acuerdo con las necesidades presentes en su comunidad. Lo cual quiere decir que, aunque son de libre inversión, los recursos captados por medio de este impuesto deben destinarse a crear mejores condiciones de vida para todos. Finalmente, se ofrece información sobre los sectores sociales entre los cuales la administración municipal de Pijiño del Carmen procedió a distribuir los recursos del impuesto en de los años 2013 y 2014, reafirmando la importancia de que las entidades territoriales cuenten con mecanismos constitucionales y legales que les otorguen autonomía para programar sus presupuestos de acuerdo con las problemáticas locales

A New Light Sensing Module for Mica Motes

We present the Ping-Pong mote, a new light sensing module for the Mica mote platform. The Ping-pong mote achieves performance comparable to a commercial light intensity meter, while conforming to the size and energy constraints imposed by its application in wireless sensor networks. The Ping-pong mote was developed to replace the Mica sensor board (MTS310) whose slow response time and narrow dynamic range in light intensity capture is unsuitable to many applications, including media production. The Ping-pong mote features significantly improved SNR due to its adoption of high-end photo sensors, amplification and conversion circuits coupled with active noise suppression, application-tuned filter networks, and a noise-attentive manual layout

A New Light Sensing Module for Mica Motes

We present the Ping-Pong mote, a new light sensing module for the Mica mote platform. The Ping-pong mote achieves performance comparable to a commercial light intensity meter, while conforming to the size and energy constraints imposed by its application in wireless sensor networks. The Ping-pong mote was developed to replace the Mica sensor board (MTS310) whose slow response time and narrow dynamic range in light intensity capture is unsuitable to many applications, including media production. The Ping-pong mote features significantly improved SNR due to its adoption of high-end photo sensors, amplification and conversion circuits coupled with active noise suppression, application-tuned filter networks, and a noise-attentive manual layout

The Westwood Experience: Connecting story to locations via Mixed Reality

Figure 1: Some of the components of the experience. From left to right: the mayor character, the game played in the theater, the panorama effect in front of Yamato, details of the set at the brewery, Marilyn Monroe’s grave. The Westwood Experience is a location-based narrative using Mixed Reality effects to connect participants to unique and evoca-tive real locations, bridging the gap between the real and story worlds. This paper describes the experience and a detailed eval-uation of it. The experience itself centers around a narrative told by the “mayor ” of Westwood. He tells a love story from his youth when he first came to Westwood, and intermixes the story with his-torical information. Most of this story is told on a mobile computer, using Mixed Reality and video for illustration. We evaluate the experience both quantitatively and qualitatively to find lessons learned about the experience itself and general guide-lines for this type of experience. The analysis and guidelines from our evaluation are grouped into three categories: narration in mo-bile environments, social dynamics, and Mixed Reality effects