Oil recovery from a reservoir involves quite a lot of challenges related to well placement before any action can be taken. An important step is proposing a reservoir target area that provides an indication of high potential for oil... more
Oil recovery from a reservoir involves quite a lot of challenges related to well placement before any action can be taken. An important step is proposing a reservoir target area that provides an indication of high potential for oil recovery. In other words, a position presenting high productivity potential according to some criteria. A simple proposal is the potential productivity proxy function (PP) based on the oil-bearing and mobility capacities of oil suggested as $$\phi k{S_{\rm o}}^n$$ ϕ k S o n , where n is a correlation parameter, $$\phi$$ ϕ is porosity, k is absolute permeability and $$S_{\rm o}$$ S o is oil saturation at grid block. In this paper, we consider this proxy function as a well placement strategy based on the column-wise ($${\text {PP}}_{\rm C}$$ PP C ) and layer-wise ($${\text {PP}}_{\rm L}$$ PP L ) values. To test this model, the UNISIM-I-D and PUNQ-S3 synthetic reservoirs are considered. Several production simulations are realized assuming a set of vertical w...
Este artigo apresenta uma aplicação da centralidade de intermediação da teoria dos grafos como parâmetro para o posicionamento de poços multilaterais em reservatórios de petróleo.
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The paper presents the application of model- based systems technology within a decision sup- port system for drinking water treatment plants. This system aims at detecting deviations from normal plant operation, identifying their possible... more
The paper presents the application of model- based systems technology within a decision sup- port system for drinking water treatment plants. This system aims at detecting deviations from normal plant operation, identifying their possible causes, and proposing adequate remedial inter- ventions. Its basis is a library of model frag- ments that represent intended processes, distur- bances, and possible interventions. Based
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Wildland fires in relatively homogeneous terrains and vegetation motivates this work which considers the formation of green islands, regions of vegetation that become enclosed and eventually engulfed by the fire. A Voronoi growth model... more
Wildland fires in relatively homogeneous terrains and vegetation motivates this work which considers the formation of green islands, regions of vegetation that become enclosed and eventually engulfed by the fire. A Voronoi growth model adequately represents the spreading of a fire from isolated point-like sources. Using this model, it is possible to predict the green island formations. First, we introduce
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In this paper we present the geometrical construction of an approximate generalized Voronoi diagram for generalized polygons and circular objects based on their minimum geometrical structure that are extracted from the object's... more
In this paper we present the geometrical construction of an approximate generalized Voronoi diagram for generalized polygons and circular objects based on their minimum geometrical structure that are extracted from the object's digital image. The construction is done in ) (n O time complexity, where n is the number of single points defining the set of objects. An application of
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During the last couple of years much attention has been given to an important ecological problem, namely forestwildfire [1]. In a recent report [5] it has been shown that, starting with very simple assumptions, a Voronoi diagramstructure... more
During the last couple of years much attention has been given to an important ecological problem, namely forestwildfire [1]. In a recent report [5] it has been shown that, starting with very simple assumptions, a Voronoi diagramstructure [4], [3] naturally emerges as the landscape geometry generated by the spread out of forest wildfire. Inthis paper, we provide a tool that
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REDUCE[2, 3], like many modern Computer Algebra Systems (CAS) (MACSYMA, MATHEMATICA, MAPLE, SCRATCHPAD to name a few), embodies a large amount of mathematical knowledge which is spread out through thousands of procedures in the source... more
REDUCE[2, 3], like many modern Computer Algebra Systems (CAS) (MACSYMA, MATHEMATICA, MAPLE, SCRATCHPAD to name a few), embodies a large amount of mathematical knowledge which is spread out through thousands of procedures in the source code of the system. Most of this knowledge is, however, in an implicit form almost inaccessible to the user, who would have to decipher the source files to recover it. Also, to profit from it one needs to know in addition the capabilities of these computing systems and how to operate them.
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One of the very basic rules we learn in an introductory course of physics is that two physical quantities, say Q1 and Q2, can only be compared when they have the same dimensional representation and, in addition, should be in the same... more
One of the very basic rules we learn in an introductory course of physics is that two physical quantities, say Q1 and Q2, can only be compared when they have the same dimensional representation and, in addition, should be in the same system of units. This rule is also frequently applied to discard non-matching physcial formulae. In other words, the
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This paper discusses the techniques and their applications in the development of a path planning system composed of three modules, namely: global vision (GVM), trajectory planning (TPM) and navigation control (NCM). The GVM captures and... more
This paper discusses the techniques and their applications in the development of a path planning system composed of three modules, namely: global vision (GVM), trajectory planning (TPM) and navigation control (NCM). The GVM captures and processes the workspace image to identify the obstacle and the robot configurations. These configurations are used by the TPM to generate the Voronoi roadmap, to compute the maximal clearance shortest feasible path and the visibility pathway between two configurations. The NCM controls the robot functionalities and navigation. To validate the path planning system, three sets of experiments have been conducted using the Lab robot Khepera, which have shown very good results.
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In a granular porous medium the packing configuration and the shape of the grains influence how fluid flows through it. This is directly related to the porosity and tortuosity of the pore space. In this paper we present an analytical... more
In a granular porous medium the packing configuration and the shape of the grains influence how fluid flows through it. This is directly related to the porosity and tortuosity of the pore space. In this paper we present an analytical function relating the porosity φ and the tortuosity τ of a granular pore medium by means of a packing parameter B. A general expression to estimate B for different representative elementary volumes and grain shapes is presented; in particular, for polyhedral packings. Exploring the packing parameter properties, we discuss the nonuniqueness of the packing-shape combination in relation to B and the porosity behavior for the special cases 0<B<1, B=1, and B>1.
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The paper presents some foundations for the application of model- based systems technology within a decision support system for drinking water treatment plants. This system aims at detecting deviations from normal plant operation,... more
The paper presents some foundations for the application of model- based systems technology within a decision support system for drinking water treatment plants. This system aims at detecting deviations from normal plant operation, identifying their possible causes, and proposing adequate remedial interventions. Its basis is a library of model fragments that represent intended processes, disturbances, and possible interventions. Based on these fragments and the available observations, possible models of the disturbed plant behavior are generated automatically as a solution to the diagnostic task. An extension of such a model by models of interventions such that the result is consistent with remedial goals represents a possible therapy proposal. We discuss in more detail how the model and consistency-based problem solving can be exploited in the basic reasoning steps.
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The paper presents the application of model-based systems technology within a decision support system for drinking water treatment plants. This system aims at detecting deviations from normal plant operation, identifying their possible... more
The paper presents the application of model-based systems technology within a decision support system for drinking water treatment plants. This system aims at detecting deviations from normal plant operation, identifying their possible causes, and proposing adequate remedial interventions. Its basis is a library of model fragments that represent intended processes, disturbances, and possible interventions. Based on these fragments and the available observations, possible models of the disturbed plant behavior are generated automatically as a solution to the
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With the elderly population increase, osteoporosis and its consequences have become not just a health issue but also a serious economic burden. The trabecular bone structure plays a very important role for the bone quality and mechanical... more
With the elderly population increase, osteoporosis and its consequences have become not just a health issue but also a serious economic burden. The trabecular bone structure plays a very important role for the bone quality and mechanical competence of the scaffold. Currently, it is claimed that the trabecular microarchitecture understanding can improve the fracture risk prediction above 65%. Several parameters seem to be correlated providing structural details of the trabecular bone network. However, the tortuosity of the trabeculae has not yet been systematically taken into account and its contribution has not been fully investigated and understood. In this paper, we discuss the relationship between the trabecular tortuosity, connectivity, volume fraction, and elasticity, and provide a unified parameter to estimate the mechanical competence of the structure. It is shown that the trabecular network tortuosity presents high linear correlation with the other parameters and that the trabeculae tend to get aligned in the direction where the structure is mostly submitted to stress, corresponding to higher stiffness orientation. This new parameter will help to integrate the relevant information of bone microarchitecture quality and assess more directly the real trabecular fragility in osteoporotic patients.
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... space-time event, the effective density of the matter experienced by such particles is much higher than that experienced by a funda-mental observer ... A distortion-free focusing takes place in the orthogonal 2-spaces (spanned by... more
... space-time event, the effective density of the matter experienced by such particles is much higher than that experienced by a funda-mental observer ... A distortion-free focusing takes place in the orthogonal 2-spaces (spanned by vectors r where rara = 1, raKa = O, raua = 0), with ...