Análisis estratégico del sector automotriz en Colombia

Esta investigación se desarrolló con el fin de conocer de conocer detalladamente el comportamiento del sector automotriz de Colombia en los últimos años, haciendo énfasis en el segmento de vehículos de gama media del mercado, los cuales son los más comprados en volumen por los colombianos. El estudio se realizó en un periodo comprendido entre 2.006 y 2.011 para tener identificación y valoración real del sector hasta la situación actual, donde se evaluaron las ensambladoras presentes en el país que pertenecen a la división o clasificación arancelaria dada por Código Industrial Internacional Uniforme - CIIU. El trabajo se fundamenta en la metodología del Análisis Estructural de Sectores Estratégicos por medio del cual es necesario desarrollar un examen histórico del comportamiento del sector en los últimos años con el cual se presenta el desarrollo en términos económicos, ventas, estado de hacinamiento, manchas blancas, principales participantes del mercado, TLC´s y demás rubros que caracterizan el segmento. De igual manera, el trabajo de investigación refleja una vista general de las estrategias utilizadas por las principales marcas del estudio, evaluando como estas son imitadas o no por sus competidores, y de igual manera, determinar que hace a una empresa ser líder en el mercado no tan solo tomando el ámbito económico como pilar.This research was developed to meet an expert understanding of the behavior of the automotive sector in Colombia in recent years, emphasizing the vehicle segment of mid-range market, which are best purchased in volume by Colombians. The study was conducted in the period between 2006 and 2011 to have identification and real assessment of the sector to the current situation, which evaluated the assemblers in the country belonging to the division or tariff classification given by the Código Industrial Internacional Uniforme - CIIU. The work is based on the methodology of Análisis Estructural de Sectores Estratégicos by which it is necessary to develop a historical examination of the performance of the sector in recent years which is presented in economic development, sales, state of overcrowding, white spots, leading market participants, Free Trade Agreement and other items that characterize the segment. Similarly, the research reflects an overview of the strategies used by the major brands of the study, evaluating how they are been mimicked or not by their competitors, and likewise, determine what makes a company a leader in the market not only taking the economic as a pillar.Centro de Estudios Empresariales para la Perdurabilida

OCT assessment of aortic wall degradation for surgical guidance

The degradation of the wall in large cardiovascular vessels, such as the aorta artery, induces weakness in the vessel that can lead to the formation of aneurysms and the rupture of the vessel. Characterization of the wall integrity is assessed by OCT for future intraoperative assistance in aneurysm graft surgery interventions. Optical Coherence Tomography (OCT) provides cross sectional images of the wall of the aortic media layer. Wall degradations appear as spatial anomalies in the reflectivity profile through the wall thickness. Wall degradation assessment is proposed by automatic identification and dimensioning of these anomalies within the homogeneous surrounding tissue

Identification of vessel wall degradation in ascending thoracic aortic aneurysms with OCT

Degradation of the wall of human ascending thoracic aorta has been assessed through Optical Coherence Tomography (OCT). OCT images of the media layer of the aortic wall exhibit micro-structure degradation in case of diseased aortas from aneurysmal vessels. The OCT indicator of degradation depends on the dimension of areas of the media layer where backscattered reflectivity becomes smaller due to a disorder on the morphology of elastin, collagen and smooth muscle cells (SMCs). Efficient pre-processing of the OCT images is required to accurately extract the dimension of degraded areas after an optimized thresholding procedure. OCT results have been validated against conventional histological analysis. The OCT qualitative assessment has achieved a pair sensitivity-specificity of 100%-91.6% in low-high degradation discrimination when a threshold of 4965.88μm2 is selected. This threshold suggests to have physiological meaning. The OCT quantitative evaluation of degradation achieves a correlation of 0.736 between the OCT indicator and the histological score. This in-vitro study can be transferred to the clinical scenario to provide an intraoperative assessment tool to guide cardiovascular surgeons in open repair interventions

Optical coherence tomography assessment of vessel wall degradation in aneurysmatic thoracic aortas

Optical coherence tomographic images of ascending thoracic human aortas from aneurysms exhibit disorders on the smooth muscle cell structure of the media layer of the aortic vessel as well as elastin degradation. Ex-vivo measurements of human samples provide results that correlate with pathologist diagnosis in aneurysmatic and control aortas. The observed disorders are studied as possible hallmarks for aneurysm diagnosis. To this end, the backscattering profile along the vessel thickness has been evaluated by fitting its decay against two different models, a third order polynomial fitting and an exponential fitting. The discontinuities present on the vessel wall on aneurysmatic aortas are slightly better identified with the exponential approach. Aneurysmatic aortic walls present uneven reflectivity decay when compared with healthy vessels. The fitting error has revealed as the most favorable indicator for aneurysm diagnosis as it provides a measure of how uniform is the decay along the vessel thickness.This work has been supported by the Spanish Government through CYCIT projects DA2TOI (FIS2010-19860), TFS (TEC2010-20224-C02-02) and the Alma’s Eguizabal PhD Grant (FPU12/04130

Enhanced delineation of degradation in aortic walls through OCT

Degradation of the wall of human ascending thoracic aorta has been assessed through Optical Coherence Tomography (OCT). OCT images of the media layer of the aortic wall exhibit micro-structure degradation in case of diseased aortas from aneurysmal vessels or in aortas prone to aortic dissections. The degeneration in vessel walls appears as low-reflectivity areas due to the invasive appearance of acidic polysaccharides and mucopolysaccharides within a typical ordered microstructure of parallel lamellae of smooth muscle cells, elastin and collagen fibers. An OCT indicator of wall degradation can be generated upon the spatial quantification of the extension of degraded areas in a similar way as conventional histopathology. This proposed OCT marker offers a real-time clinical insight of the vessel status to help cardiovascular surgeons in vessel repair interventions. However, the delineation of degraded areas on the B-scan image from OCT is sometimes difficult due to presence of speckle noise, variable SNR conditions on the measurement process, etc. Degraded areas could be outlined by basic thresholding techniques taking advantage of disorders evidences in B-scan images, but this delineation is not always optimum and requires complex additional processing stages. This work proposes an optimized delineation of degraded spots in vessel walls, robust to noisy environments, based on the analysis of the second order variation of image intensity of backreflection to determine the type of local structure. Results improve the delineation of wall anomalies providing a deeper physiological perception of the vessel wall conditions. Achievements could be also transferred to other clinical scenarios: carotid arteries, aorto-iliac or ilio-femoral sections, intracranial, etc.This work has been supported by the Spanish Government through the CYCIT projects DA2TOI (FIS2010-19860) and FOS4 (TEC2013-47264-C2-1-R)

Identification of vessel wall anomalies in thoracic aortic aneurysms through optical coherence tomography and gradient-based strategies

Optical Coherence Tomography is a natural candidate for imaging biological structures just under tissue surface. Human thoracic aorta from aneurysms reveal elastin disorders and smooth muscle cell alterations when visualizing the media layer of the aortic wall, which is only some tens of microns in depth from surface. The resulting images require a suitable processing to enhance interesting disorder features and to use them as indicators for wall degradation, converting OCT into a hallmark for diagnosis of risk of aneurysm under intraoperative conditions. This work proposes gradient-based digital image processing approaches to conclude this risk. These techniques are believed to be useful in these applications as aortic wall disorders directly affect the refractive index of the tissue, having an effect on the gradient of the tissue reflectivity that conform the OCT image. Preliminary results show that the direction of the gradient contains information to estimate the tissue abnormality score. The detection of the edges of the OCT image is performed using the Canny algorithm. The edges delineate tissue disorders in the region of interest and isolate the abnormalities. These edges can be quantified to estimate a degradation score. Furthermore, the direction of the gradient seems to be a promising enhancement technique, as it detects areas of homogeneity in the region of interest. Automatic results from gradient-based strategies are finally compared to the histopathological global aortic score, which accounts for each risk factor presence and seriousness

Optical coherence tomography assessment of vessel wall degradation in thoracic aortic aneurysms

Optical coherence tomography images of human thoracic aorta from aneurysms reveal elastin disorders and smooth muscle cell alterations when visualizing the media layer of the aortic wall. These disorders can be employed as indicators for wall degradation and, therefore, become a hallmark for diagnosis of risk of aneurysm under intraoperative conditions. Two approaches are followed to evaluate this risk: the analysis of the reflectivity decay along the penetration depth and the textural analysis of a two-dimensional spatial distribution of the aortic wall backscattering. Both techniques require preprocessing stages for the identification of the air–sample interface and for the segmentation of the media layer. Results show that the alterations in the media layer of the aortic wall are better highlighted when the textural approach is considered and also agree with a semiquantitative histopathological grading that assesses the degree of wall degradation. The correlation of the co-occurrence matrix attains a sensitivity of 0.906 and specificity of 0.864 when aneurysm automatic diagnosis is evaluated with a receiver operating characteristic curve

Detección de anomalías en la pared aortica a través de análisis Hessiano de imágenes de tomografía de coherencia óptica

La degradación de la arteria aorta se debe a malformaciones estructurales del tejido. Estas anomalías son visibles en forma de irregularidades y manchas cuando se interroga el tejido con tomografía de coherencia óptica. La delimitación de estas irregularidades es compleja debido a su carencia de forma determinada, ruido de medida y falta de definición de las fronteras. La aplicación de la matriz Hessiana de la imagen permite identificar y delimitar las anomalías de forma precisa

Gestión del conocimiento. Perspectiva multidisciplinaria. Volumen 17

El libro “Gestión del Conocimiento. Perspectiva Multidisciplinaria”, Volumen 17 de la Colección Unión Global, es resultado de investigaciones. Los capítulos del libro, son resultados de investigaciones desarrolladas por sus autores. El libro es una publicación internacional, seriada, continua, arbitrada, de acceso abierto a todas las áreas del conocimiento, orientada a contribuir con procesos de gestión del conocimiento científico, tecnológico y humanístico. Con esta colección, se aspira contribuir con el cultivo, la comprensión, la recopilación y la apropiación social del conocimiento en cuanto a patrimonio intangible de la humanidad, con el propósito de hacer aportes con la transformación de las relaciones socioculturales que sustentan la construcción social de los saberes y su reconocimiento como bien público

Iterative Otsu's method for OCT improved delineation in the aorta wall

Degradation of human ascending thoracic aorta has been visualized with Optical Coherence Tomography (OCT). OCT images of the vessel wall exhibit structural degradation in the media layer of the artery, being this disorder the final trigger of the pathology. The degeneration in the vessel wall appears as low-reflectivity areas due to different optical properties of acidic polysaccharides and mucopolysaccharides in contrast with typical ordered structure of smooth muscle cells, elastin and collagen fibers. An OCT dimension indicator of wall degradation can be generated upon the spatial quantification of the extension of degraded areas in a similar way as conventional histopathology. This proposed OCT marker can offer in the future a real-time clinical perception of the vessel status to help cardiovascular surgeons in vessel repair interventions. However, the delineation of degraded areas on the B-scan image from OCT is sometimes difficult due to presence of speckle noise, variable signal to noise ratio (SNR) conditions on the measurement process, etc. Degraded areas can be delimited by basic thresholding techniques taking advantage of disorders evidences in B-scan images, but this delineation is not optimum in the aorta samples and requires complex additional processing stages. This work proposes an optimized delineation of degraded areas within the aorta wall, robust to noisy environments, based on the iterative application of Otsu’s thresholding method. Results improve the delineation of wall anomalies compared with the simple application of the algorithm. Achievements could be also transferred to other clinical scenarios: carotid arteries, aorto-iliac or ilio-femoral sections, intracranial, etc.This work has been supported by projects DA2TOI (FIS2010-19860) and FOS4 (TEC2013-47264-C2-1-R)