OALib Journal期刊

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匹配条件: “Dioén Biosca Rojas” ,找到相关结果约202467条。
Estructuras de Monte Carlo para el análisis del desempe?o de OOK y L-PPM en canales ópticos inalámbricos infrarrojos en interiores
Biosca Rojas,Dioén; López Presmanes,Jorge Luis;
Universidad, Ciencia y Tecnología , 2006,
Abstract: in this paper a new simulation framework, based on monte carlo analysis, is proposed to allow performance studies of ook and l-ppm in the wireless indoor infrared channel. it is assumed that the impulse response of the channel is known and that it is obtained previously by simulation using a ray-tracing algorithm. in the case of ook, along with the monte carlo simulation structure, an analytic expression is developed additionally to provide direct performance evaluation of ook in the wireless channel, which takes into account the effects of noise and inter symbol interference induced by multipath propagation, proper phenomena of this kind of communication channels. the simulation results obtained with the proposed simulation structures for ook and lppm are validated in both cases by comparison against theoretical results given by the evaluation of the expressions for probability of error in the awgn ideal channel, free of inter symbol interference.
Generalización del algoritmo de trazado de rayos de Monte Carlo modificado para el cálculo de la respuesta al impulso de canales ópticos infrarrojos en interiores
Biosca Rojas,Dioén; López Presmanes,Jorge Luís;
Universidad, Ciencia y Tecnología , 2005,
Abstract: in this paper a new model for the calculation of the impulse response on indoor wireless infrared channels is proposed. the use of bidirectional reflectance distribution functions on a modified monte carlo ray-tracing algorithm allows a better modeling of the reflection properties of the different reflecting surfaces present in the channel, transforming the original monte carlo scheme in a more general and accurate simulation tool. the work with reflectance functions is possible because of the derivation of the directional-hemispherical reflection coefficient as a function of reflectors material for different types of reflectors. this aspect is shown along the paper as well as the ways for obtaining reflected rays directions by sampling the reflectors reflectance function as a probability distribution function. some considerations about efficiency and convergence of the new proposed algorithm are included. also, some simulations results on typical reported configurations are presented and discussed as particular cases for the new formulation. the comparison of this results with the results reported by other authors for the same configurations is used for validating the new algorithm just presented.
Design and Analysis of a Coverage Optical Device for IR-WLAN Using SMS Method in Three Dimensions Dise o y análisis de un dispositivo óptico de cobertura para IR-WLAN por SMS en tres dimensiones
Dioén Biosca Rojas,Maikel Hernández Sanz
Revista Cubana de Ingeniería , 2010, DOI: 10.1234/rci.v1i1.5
Abstract: In this paper the features of the Simultaneous Multiple Surfaces (SMS) design method are described. The method is addressed for designing optical devices in two dimensions (2D) as well as in three dimensions (3D). A 2D design is presented as an example and a complete 3D design of a specific optical device is developed. The prototype just synthesised finds application as an optical element of coverage systems in wireless indoor infrared networks. The statement of the problem is made directly in 3D, the device is accomplished and the transmission curves obtained by simulation are presented using a commercial ray tracing software. In the field of applications, a panoramic view of different coverage systems in wireless indoor infrared networks is made and several alternatives of use are suggested for the new designed device. En el presente trabajo se describen las particularidades del método de dise o de Superficies Múltiples Simultáneas o SMS, en el dise o de dispositivos ópticos tanto en dos dimensiones (2D) como su extensión a tres dimensiones (3D). Se brinda un ejemplo de dise o de dispositivo 2D y se desarrolla particularmente el dise o de un dispositivo 3D para su aplicación como elemento óptico en sistemas de cobertura para redes inalámbricas infrarrojas en interiores. A lo largo del dise o se realiza el planteamiento del problema directamente en 3D, se obtiene el dispositivo y se presentan las curvas de transmisión del mismo obtenidas por simulación mediante trazado de rayos. Respecto a la aplicación, se realiza una panorámica de los diferentes sistemas de cobertura existentes para las redes inalámbricas infrarrojas en interiores y se presentan varias alternativas de aplicación del dispositivo dise ado en variantes de los sistemas convencionales de cobertura.
Estudio comparativo del impacto en el desarrollo socioeconómico en dos carreteras: Eix Transversal de Catalunya, Espa a, y MEX120, México
Saúl Antonio Obregón-Biosca
Economía, sociedad y territorio , 2010,
Abstract: Las carreteras son pieza clave en el desarrollo económico y social en cualquier país; por ello, se considera importante analizar y comparar cómo las carreteras proporcionan la oportunidad para la transformación económica y social. Este análisis considera dos ámbitos territoriales con algunas similitudes, pero también con diferencias sociales evidentes. Para ello, se seleccionaron dos carreteras en diferentes países con la finalidad de observar el efecto a corto plazo que tiene cada una en diversas variables socioeconómicas. Se elige por un lado el Eix Transversal de Catalunya (Espa a) y por el otro la carretera MEX120 (México). Los resultados muestran que las pautas en el desarrollo inducido por ambas carreteras son muy similares y la principal diferencia radica en el nivel de desarrollo económico en ambos territorios.
A Global Public Good: The Linkage between Veterinary Medicine and the Sanitary Management of Food Hygiene  [PDF]
Andrés Cartín Rojas
American Journal of Industrial and Business Management (AJIBM) , 2013, DOI: 10.4236/ajibm.2013.35058

Ensuring food safety is a key and crucial factor for those agro-exporting nations seeking to improve their competitiveness, opening new options for global markets and positioning their products at a better price. A number of international guidelines serve a reference framework for defining national public policies aimed to provide safe food to the population. Veterinary services act as guarantors in this process along all the manufacture and value chain. The public and private veterinary services are nurtured and amalgamate together to ensure the attainment of common goals; strengthen and foment a robust and efficient alimentary legislation by using the World Animal Health Organization’s normative as a standard reference. In this conceptual paper, an appraisal about the interrelationship and the interconnection between veterinary professionals and the sanitary management of food hygiene is widely developed by reviewing relevant literature, and discussing current trends. The author adopts an inductive approach, designed to generate understanding and propositions about this relevant topic.

Endovascular Management of Pericallosal Artery Aneurysms: A Case Report  [PDF]
Alejandro Rojas-Marroquín
Open Journal of Modern Neurosurgery (OJMN) , 2015, DOI: 10.4236/ojmn.2015.52008
Abstract: This report describes a classic case of pericallosal artery aneurysm and their Angiographic findings and endovascular management.
Gunshot Wound to the Head: Surgical Management and Cases Report in a Tertiary Care Center in Florencia, Colombia  [PDF]
Alejandro Rojas-Marroquín
Open Journal of Modern Neurosurgery (OJMN) , 2015, DOI: 10.4236/ojmn.2015.53014
Abstract: The purpose of this research is to report 10 cases treated in a tertiary care center in the Florencia town in Colombia. The time frame to this intervention was from 1st June 2011 to 30th June 2012. The idea was to establish the type, age group, Matson’s classification schemes and mortality of the gunshot wound to the head in order to describe the neurological functional prognosis of these patients, made by The Modified Rankin scale (mRS) to 12 months postoperative.
Neurofibromatose tipo 1 com manifesta o parafaríngea na infancia =Neurofibomatosis type 1 with parapharyngeal manifestation in childhood
Steffen, Nédio et al.
Scientia Medica , 2011,
Abstract: Objetivos: apresentar um caso raro de comprometimento parafaríngeo em uma crian a com neurofibromatose tipo I. Descri o do caso: uma menina de um ano e quatro meses foi trazida ao consultório de otorrinolaringologia no Hospital S o Lucas da PUCRS por aumento de volume em regi o parotídea esquerda, observado há aproximadamente 30 dias. Ao exame apresentava bom estado geral e na inspe o observou-se tumora o em regi o parotídea à esquerda, com pouca mobilidade. Uma tomografia computadorizada com contraste revelou tumora o extensa, com aparência sólida, desvio da artéria carótida interna para linha média com envolvimento da glandula parótida e extens o para o espa o parafaríngeo. A biópsia excisional transoperatória revelou neoplasia benigna de tecido neural e o resultado anatomopatológico mostrou neuroma plexiforme. Revisando-se o exame físico foram observadas três máculas hiperpigmentadas (manchas café com leite) em regi o abdominal, apontado para o diagnóstico clínico de neurofibromatose tipo I, ou doen a de Von Recklinghausen. Conclus es: o neurofibroma do espa o parafaríngeo é uma complica o rara de neurofibromatose tipo I, ocorrendo em menos de 5% das neoplasias de espa o parafaríngeo. Com este relato de caso mostra-se a importancia da correla o clínica para o diagnóstico de uma doen a rara, especialmente na faixa etária pediátrica. Aims: To present a rare case of parapharyngeal involvement in a child with neurofibromatosis type I. Case description: a girl one year and four months old was brought to the clinic of otolaryngology at the Hospital S o Lucas da PUCRS because of a swelling in the left parotid region, observed for approximately 30 days. On examination she appeared healthy, and the inspection showed a tumor on the left parotid region, with little mobility. A computed tomography scan with contrast revealed extensive tumor with solid appearance, internal carotid artery bypass to the midline with involvement of the parotid gland and extension into the parapharyngeal space. Excisional biopsy examination with trans-operative freezing revealed a benign neoplasm of neural tissue and the pathological result showed plexiform neuroma. Reviewing the physical examination, three hyperpigmented macules (café au lait spots) were observed in the abdominal region, pointing to the clinical diagnosis of neurofibromatosis type I, or Von Recklinghausen’s disease. Conclusions: Neurofibroma of the parapharyngeal space is a rare complication of neurofibromatosis type I, occurring in less than 5% of tumors of the parapharyngeal space. This case report showed th
Sífilis primária de tonsila mimetizando linfoma =Primary syphilis of the tonsil mimicking lymphoma
Steffen, Nédio et al.
Scientia Medica , 2011,
Abstract: Objetivos: descrever um incomum caso de sífilis afetando a tonsila e revisar a literatura sobre o assunto. Descri o do caso: um homem de 60 anos de idade, branco, apresentava tumefa o no lado direito do pesco o e voz hiponasal quatro meses após ter sido submetido à cirurgia para remo o de adenoma na glandula submandibular esquerda. Ao exame físico apresentava linfadenopatia cervical, e uma tomografia computadorizada mostrou massa cervical. Foi realizada pun o aspirativa por agulha fina para descartar linfoepitelioma, que n o foi conclusiva. Como a tonsila direita era claramente patológica, foi realizada uma tonsilectomia. O diagnóstico de sífilis foi estabelecido com base na análise patológica combinada com resultados dos exames de sangue. Conclus es: embora grande parte dos cancros sifilíticos apare a na regi o genital, eles podem ser vistos em outras partes do corpo. A falta de dor é um ponto chave da sífilis, juntamente com o relato do paciente da sensa o de protuberancia na garganta. Embora infrequente, a sífilis deve entrar no diagnóstico diferencial da hipertrofia tonsilar unilateral.
Imágenes marcadas a fuego: representación y memoria de la Shoah
Sánchez Biosca, Vicente;
Revista Brasileira de História , 2001, DOI: 10.1590/S0102-01882001000300002
Abstract: this article analyses the documentary shoah, dealing with the relations between images/representation and history/memory.

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