Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2013
Abstract. Clusters that combine heterogeneous compute device architectures, coupled with novel pr... more Abstract. Clusters that combine heterogeneous compute device architectures, coupled with novel programming models, have created a true alternative to traditional (homogeneous) cluster computing, allowing to leverage the performance of parallel applications. In this paper we introduce clOpenCL, a platform that supports the simple deployment and efficient running of OpenCL-based parallel applications that may span several cluster nodes, expanding the original single-node OpenCL model. clOpenCL is deployed through user ...
Abstract: Within the development of motor vehicles, crash safety is one of the most important att... more Abstract: Within the development of motor vehicles, crash safety is one of the most important attributes. To comply with the ever increasing requirements of shorter cycle times and costs reduction, car manufacturers keep intensifying the use of virtual development tools, such as, for crash simulations, the explicit finite element method (FEM). The accuracy of the simulation process is highly dependent on the accuracy of the model, including the midplane mesh.
Abstract—Within the development of motor vehicles, crash safety (eg occupant protection, pedestri... more Abstract—Within the development of motor vehicles, crash safety (eg occupant protection, pedestrian protection, low speed damageability), is one of the most important attributes. In order to be able to fulfill the increased requirements in the framework of shorter cycle times and rising pressure to reduce costs, car manufacturers keep intensifying the use of virtual development tools such as those in the domain of Computer Aided Engineering (CAE). For crash simulations, the explicit finite element method (FEM) is applied.
The aim of the COGNITO project is to design a personal assistance system, in which Augmented Real... more The aim of the COGNITO project is to design a personal assistance system, in which Augmented Reality (AR) is used to support users in task solving and manipulation of objects. Due to its sensing and learning capability, the COGNITO system automatically creates workflow references by observing a shown task in learning mode. After the workflow has been learnt, the system can be run in playback mode, in which it explains the previously learnt task to the operator.
Abstract Parallelizing rendering algorithms to exploit multiprocessor and multicore machines isn'... more Abstract Parallelizing rendering algorithms to exploit multiprocessor and multicore machines isn't straightforward. Certain methods require frequent synchronization among threads to obtain benefits similar to the sequential algorithm. One such algorithm is the irradiance cache (IC), an acceleration data structure that caches indirect diffuse irradiance values. In multicore systems, the threads must share the IC to achieve high efficiency.
Abstract The efficient execution of irregular data parallel applications, on dynamically shared c... more Abstract The efficient execution of irregular data parallel applications, on dynamically shared computing clusters, requires novel approaches to manage the runtime load distribution. Such environments have an unpredictable dynamic behaviour both due to the application requirements and to the available system's resources.
The efficient execution of irregular parallel applications on shared distributed systems requires... more The efficient execution of irregular parallel applications on shared distributed systems requires novel approaches to scheduling, since both the application requirements and the system resources exhibit an unpredictable behavior. This paper proposes Bayesian decision networks as the paradigm to handle the uncertainty a scheduler has about the environment's current and future states.
Abstract Parallelizing rendering algorithms to exploit multiprocessor and multicore machines isn'... more Abstract Parallelizing rendering algorithms to exploit multiprocessor and multicore machines isn't straightforward. Certain methods require frequent synchronization among threads to obtain benefits similar to the sequential algorithm. One such algorithm is the irradiance cache (IC), an acceleration data structure that caches indirect diffuse irradiance values. In multicore systems, the threads must share the IC to achieve high efficiency.
Resumo A sinistralidade rodoviária atinge proporções catastróficas, vitimando mortalmente, a cada... more Resumo A sinistralidade rodoviária atinge proporções catastróficas, vitimando mortalmente, a cada ano, mais de um milhão de pessoas em todo o mundo. São vários os esforços já desenvolvidos para diminuir estes números e, tendo em conta alguns dos principais factores envolvidos nos acidentes de viação, projectámos um dispositivo denominado CAPD (Car Accident Prevention Device).
Abstract The ability to interactively render dynamic scenes with global illumination is one of th... more Abstract The ability to interactively render dynamic scenes with global illumination is one of the main challenges in computer graphics. The improvement in performance of interactive ray tracing brought about by significant advances in hardware and careful exploitation of coherence has rendered the potential of interactive global illumination a reality. However, the simulation of complex light transport phenomena, such as diffuse interreflections, is still quite costly to compute in real time.
Precomputed Radiance Transport (PRT) was introduced as a technique to enable interactive navigati... more Precomputed Radiance Transport (PRT) was introduced as a technique to enable interactive navigation and distant environmental real time relighting of rigid scenes. Evaluating radiance transport is, however, a computationally very demanding task, which precludes PRT's utilization during the model design phase, since the user must wait for long periods of time before being able to light and navigate within the model.
Abstract The computational requirements of full global illumination rendering are such that it is... more Abstract The computational requirements of full global illumination rendering are such that it is still not possible to achieve high-fidelity graphics of very complex scenes in a reasonable time on a single computer. By identifying which computations are more relevant to the desired quality of the solution, selective rendering can significantly reduce rendering times.
Computer Graphics and Visualization are two fields that continue to evolve at a fast pace, always... more Computer Graphics and Visualization are two fields that continue to evolve at a fast pace, always addressing new application areas and achieving better and faster results. The volume of data processed by such applications keeps getting larger and the illumination and light transport models used to generate pictorial representations of this data keep getting more sophisticated.
Abstract. The main role of a scheduler on a distributed environment is to effectively and efficie... more Abstract. The main role of a scheduler on a distributed environment is to effectively and efficiently manage the code and data workload distribution. The scheduling context is presented to identify its main components and their role. To analyse the structure of a generic scheduler three main features are identified and further detailed: the performance model (effectiveness, environment and scheduling overheads metrics), the internal execution model and the decision making mechanism.
Abstract. Clusters that combine heterogeneous compute device architectures, coupled with novel pr... more Abstract. Clusters that combine heterogeneous compute device architectures, coupled with novel programming models, have created a true alternative to traditional (homogeneous) cluster computing, allowing to leverage the performance of parallel applications. In this paper we introduce clOpenCL, a platform that supports the simple deployment and efficient running of OpenCL-based parallel applications that may span several cluster nodes, expanding the original single-node OpenCL model.
Over the last two decades, there have been many high profile success stories where cutting edge c... more Over the last two decades, there have been many high profile success stories where cutting edge computer graphics (CG) technology was used in collaboration with cultural heritage (CH) professionals to unlock the secrets of humanity's legacy.
Within the development of motor vehicles, crash safety is one of the most important attributes. T... more Within the development of motor vehicles, crash safety is one of the most important attributes. To comply with the ever increasing requirements of shorter cycle times and costs reduction, car manufacturers keep intensifying the use of virtual development tools, such as, for crash simulations, the explicit finite element method (FEM). The accuracy of the simulation process is highly dependent on the accuracy of the model, including the midplane mesh.
Abstract In the real world, the human eye is confronted with a wide range of luminances from brig... more Abstract In the real world, the human eye is confronted with a wide range of luminances from bright sunshine to low night light. Our eyes cope with this vast range of intensities by adaptation; changing their sensitivity to be responsive at different illumination levels. This adaptation is highly localized, allowing us to see both dark and bright regions of a high dynamic range environment. In this paper we present a new model of eye adaptation based on physiological data.
Abstract Interactive navigation within virtual archaeological models using global illumination al... more Abstract Interactive navigation within virtual archaeological models using global illumination algorithms is a major challenge due to the huge computational requirements associated with these algorithms. We present a framework to achieve this goal, based on image space subsampling, parallel rendering, exploitation of spatiotemporal coherence and progressive refinement. Results, obtained with a prototype and a model of the roman town of Bracara Augusta, suggest that this is a promising approach.
The irradiance cache is an acceleration data structure which caches indirect diffuse samples with... more The irradiance cache is an acceleration data structure which caches indirect diffuse samples within the framework of a distributed ray-tracing algorithm. Previously calculated values can be stored and reused in future calculations, resulting in an order of magnitude improvement in computational performance. However, the irradiance cache is a shared data structure and so it is notoriously difficult to parallelise over a distributed parallel system. The hurdle to overcome is when and how to share cached samples.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2013
Abstract. Clusters that combine heterogeneous compute device architectures, coupled with novel pr... more Abstract. Clusters that combine heterogeneous compute device architectures, coupled with novel programming models, have created a true alternative to traditional (homogeneous) cluster computing, allowing to leverage the performance of parallel applications. In this paper we introduce clOpenCL, a platform that supports the simple deployment and efficient running of OpenCL-based parallel applications that may span several cluster nodes, expanding the original single-node OpenCL model. clOpenCL is deployed through user ...
Abstract: Within the development of motor vehicles, crash safety is one of the most important att... more Abstract: Within the development of motor vehicles, crash safety is one of the most important attributes. To comply with the ever increasing requirements of shorter cycle times and costs reduction, car manufacturers keep intensifying the use of virtual development tools, such as, for crash simulations, the explicit finite element method (FEM). The accuracy of the simulation process is highly dependent on the accuracy of the model, including the midplane mesh.
Abstract—Within the development of motor vehicles, crash safety (eg occupant protection, pedestri... more Abstract—Within the development of motor vehicles, crash safety (eg occupant protection, pedestrian protection, low speed damageability), is one of the most important attributes. In order to be able to fulfill the increased requirements in the framework of shorter cycle times and rising pressure to reduce costs, car manufacturers keep intensifying the use of virtual development tools such as those in the domain of Computer Aided Engineering (CAE). For crash simulations, the explicit finite element method (FEM) is applied.
The aim of the COGNITO project is to design a personal assistance system, in which Augmented Real... more The aim of the COGNITO project is to design a personal assistance system, in which Augmented Reality (AR) is used to support users in task solving and manipulation of objects. Due to its sensing and learning capability, the COGNITO system automatically creates workflow references by observing a shown task in learning mode. After the workflow has been learnt, the system can be run in playback mode, in which it explains the previously learnt task to the operator.
Abstract Parallelizing rendering algorithms to exploit multiprocessor and multicore machines isn'... more Abstract Parallelizing rendering algorithms to exploit multiprocessor and multicore machines isn't straightforward. Certain methods require frequent synchronization among threads to obtain benefits similar to the sequential algorithm. One such algorithm is the irradiance cache (IC), an acceleration data structure that caches indirect diffuse irradiance values. In multicore systems, the threads must share the IC to achieve high efficiency.
Abstract The efficient execution of irregular data parallel applications, on dynamically shared c... more Abstract The efficient execution of irregular data parallel applications, on dynamically shared computing clusters, requires novel approaches to manage the runtime load distribution. Such environments have an unpredictable dynamic behaviour both due to the application requirements and to the available system's resources.
The efficient execution of irregular parallel applications on shared distributed systems requires... more The efficient execution of irregular parallel applications on shared distributed systems requires novel approaches to scheduling, since both the application requirements and the system resources exhibit an unpredictable behavior. This paper proposes Bayesian decision networks as the paradigm to handle the uncertainty a scheduler has about the environment's current and future states.
Abstract Parallelizing rendering algorithms to exploit multiprocessor and multicore machines isn'... more Abstract Parallelizing rendering algorithms to exploit multiprocessor and multicore machines isn't straightforward. Certain methods require frequent synchronization among threads to obtain benefits similar to the sequential algorithm. One such algorithm is the irradiance cache (IC), an acceleration data structure that caches indirect diffuse irradiance values. In multicore systems, the threads must share the IC to achieve high efficiency.
Resumo A sinistralidade rodoviária atinge proporções catastróficas, vitimando mortalmente, a cada... more Resumo A sinistralidade rodoviária atinge proporções catastróficas, vitimando mortalmente, a cada ano, mais de um milhão de pessoas em todo o mundo. São vários os esforços já desenvolvidos para diminuir estes números e, tendo em conta alguns dos principais factores envolvidos nos acidentes de viação, projectámos um dispositivo denominado CAPD (Car Accident Prevention Device).
Abstract The ability to interactively render dynamic scenes with global illumination is one of th... more Abstract The ability to interactively render dynamic scenes with global illumination is one of the main challenges in computer graphics. The improvement in performance of interactive ray tracing brought about by significant advances in hardware and careful exploitation of coherence has rendered the potential of interactive global illumination a reality. However, the simulation of complex light transport phenomena, such as diffuse interreflections, is still quite costly to compute in real time.
Precomputed Radiance Transport (PRT) was introduced as a technique to enable interactive navigati... more Precomputed Radiance Transport (PRT) was introduced as a technique to enable interactive navigation and distant environmental real time relighting of rigid scenes. Evaluating radiance transport is, however, a computationally very demanding task, which precludes PRT's utilization during the model design phase, since the user must wait for long periods of time before being able to light and navigate within the model.
Abstract The computational requirements of full global illumination rendering are such that it is... more Abstract The computational requirements of full global illumination rendering are such that it is still not possible to achieve high-fidelity graphics of very complex scenes in a reasonable time on a single computer. By identifying which computations are more relevant to the desired quality of the solution, selective rendering can significantly reduce rendering times.
Computer Graphics and Visualization are two fields that continue to evolve at a fast pace, always... more Computer Graphics and Visualization are two fields that continue to evolve at a fast pace, always addressing new application areas and achieving better and faster results. The volume of data processed by such applications keeps getting larger and the illumination and light transport models used to generate pictorial representations of this data keep getting more sophisticated.
Abstract. The main role of a scheduler on a distributed environment is to effectively and efficie... more Abstract. The main role of a scheduler on a distributed environment is to effectively and efficiently manage the code and data workload distribution. The scheduling context is presented to identify its main components and their role. To analyse the structure of a generic scheduler three main features are identified and further detailed: the performance model (effectiveness, environment and scheduling overheads metrics), the internal execution model and the decision making mechanism.
Abstract. Clusters that combine heterogeneous compute device architectures, coupled with novel pr... more Abstract. Clusters that combine heterogeneous compute device architectures, coupled with novel programming models, have created a true alternative to traditional (homogeneous) cluster computing, allowing to leverage the performance of parallel applications. In this paper we introduce clOpenCL, a platform that supports the simple deployment and efficient running of OpenCL-based parallel applications that may span several cluster nodes, expanding the original single-node OpenCL model.
Over the last two decades, there have been many high profile success stories where cutting edge c... more Over the last two decades, there have been many high profile success stories where cutting edge computer graphics (CG) technology was used in collaboration with cultural heritage (CH) professionals to unlock the secrets of humanity's legacy.
Within the development of motor vehicles, crash safety is one of the most important attributes. T... more Within the development of motor vehicles, crash safety is one of the most important attributes. To comply with the ever increasing requirements of shorter cycle times and costs reduction, car manufacturers keep intensifying the use of virtual development tools, such as, for crash simulations, the explicit finite element method (FEM). The accuracy of the simulation process is highly dependent on the accuracy of the model, including the midplane mesh.
Abstract In the real world, the human eye is confronted with a wide range of luminances from brig... more Abstract In the real world, the human eye is confronted with a wide range of luminances from bright sunshine to low night light. Our eyes cope with this vast range of intensities by adaptation; changing their sensitivity to be responsive at different illumination levels. This adaptation is highly localized, allowing us to see both dark and bright regions of a high dynamic range environment. In this paper we present a new model of eye adaptation based on physiological data.
Abstract Interactive navigation within virtual archaeological models using global illumination al... more Abstract Interactive navigation within virtual archaeological models using global illumination algorithms is a major challenge due to the huge computational requirements associated with these algorithms. We present a framework to achieve this goal, based on image space subsampling, parallel rendering, exploitation of spatiotemporal coherence and progressive refinement. Results, obtained with a prototype and a model of the roman town of Bracara Augusta, suggest that this is a promising approach.
The irradiance cache is an acceleration data structure which caches indirect diffuse samples with... more The irradiance cache is an acceleration data structure which caches indirect diffuse samples within the framework of a distributed ray-tracing algorithm. Previously calculated values can be stored and reused in future calculations, resulting in an order of magnitude improvement in computational performance. However, the irradiance cache is a shared data structure and so it is notoriously difficult to parallelise over a distributed parallel system. The hurdle to overcome is when and how to share cached samples.
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Papers by Luis Paulo Santos