Antonio Rodriguez - Academia.edu (original) (raw)

Papers by Antonio Rodriguez

arXiv (Cornell University), Nov 30, 2021

Kulkarni et al. UVEX is a proposed medium class Explorer mission designed to provide crucial miss... more Kulkarni et al. UVEX is a proposed medium class Explorer mission designed to provide crucial missing capabilities that will address objectives central to a broad range of modern astrophysics. The UVEX design has two co-aligned wide-field imagers operating in the FUV and NUV and a powerful broad band medium resolution spectrometer. In its two-year baseline mission, UVEX will perform a multi-cadence synoptic all-sky survey 50/100 times deeper than GALEX in the near/far ultraviolet, cadenced surveys of the Large and Small Magellanic Clouds, rapid target of opportunity follow-up, as well as spectroscopic followup of samples of stars and galaxies. The science program is built around three pillars. First, UVEX will explore the low-mass, low-metallicity galaxy frontier through imaging and spectroscopic surveys that will probe key aspects of the evolution of galaxies by understanding how star formation and stellar evolution at low metallicities affect the growth and evolution of low-metallicity, low-mass galaxies in the local universe. Such galaxies contain half the mass in the local universe, and are analogs for the first galaxies, but observed at distances that make them accessible to detailed study. Second, UVEX will explore the dynamic universe through time-domain surveys and prompt spectroscopic followup capability will probe the environments, energetics, and emission processes in the early aftermaths of gravitational wave-discovered compact object mergers, discover hot, fast UV transients, and diagnose the early stages of stellar explosions. Finally, UVEX will become a key community resource by leaving a large all-sky legacy data set, enabling a wide range of scientific studies and filling a gap in the new generation of wide-field, sensitive optical and infrared surveys provided by the Rubin, Euclid , and Roman observatories. This paper discusses the scientific potential of UVEX , and the broad scientific program.

Research Notes of the AAS, 2022

Tumer et al. 2022, ATel #15171) have recently reported the discovery of an X-ray source, NuSTAR J... more Tumer et al. 2022, ATel #15171) have recently reported the discovery of an X-ray source, NuSTAR J053449+2126.0, during a calibration observation which took place on 25 April 2020. We scan the Zwicky Transient Facility (ZTF) alerts and archival photometry to determine the nature of the source. Palomar Gattini-IR is searched as well. We identify no obvious counterpart candidate. Follow-up X-ray and optical studies are needed to determine the true counterpart.

The Astrophysical Journal, 2022

We apply a conventional accretion disk model to the FU Ori–type objects HBC 722 and Gaia 17bpi. O... more We apply a conventional accretion disk model to the FU Ori–type objects HBC 722 and Gaia 17bpi. Our base model is a steady-state, thin Keplerian disk featuring a modified Shakura–Sunyaev temperature profile, with each annulus radiating as an area-weighted spectrum given by a NextGen atmosphere at the appropriate temperature. We explore departures from the standard model by altering the temperature distribution in the innermost region of the disk to account for “boundary region”–like effects. We consider the overall spectral energy distribution as well as medium- and high-resolution spectra in evaluating best-fit models to the data. Parameter degeneracies are studied via a Markov Chain Monte Carlo parameter estimation technique. Allowing all parameters to vary, we find accretion rates for HBC 722 of M ̇ = 10 − 4.90 M ⊙ yr − 1 − 0.40 + 0.99 dex and for Gaia 17bpi of M ̇ = 10 − 6.70 M ⊙ yr − 1 − 0.36 + 0.46 dex ; the corresponding maximum disk temperatures are 7100 − 500 + 300 K and 79...

Botanical Sciences, 2017

Background. Abiotic constraints, historical effects of the last glaciation, and differential disp... more Background. Abiotic constraints, historical effects of the last glaciation, and differential dispersal, have been proposed as potential explanations to account for the latitudinal decrease in acorn size of wide-ranging oak species distributed in the U.S. and Canada. Hypothesis. We specifically tested the abiotic constraints hypothesis on oak acorn size in a geographical area without the counfounding influence of glaciation and related dispersal history. Data description. Acorns from seven populations of the white oak Quercus rugosa were collected, encompassing the distribution of the species in Mexico. Study site and years of study. Mexico, 2009-2010. Results. Acorn length, width, mass and volume differed significantly among populations and indicated a marked clinal latitudinal reduction in acorn size. A multiple regression model revealed that this reduction in size (measured as acorn volume) can be explained by two important bioclimatic variables (growing season precipitation and g...

IECON 2010 - 36th Annual Conference on IEEE Industrial Electronics Society, 2010

This paper describes a solution to a mobile climbing robot on magnetic wheels, designed for inspe... more This paper describes a solution to a mobile climbing robot on magnetic wheels, designed for inspecting exterior oil tank surfaces made of metal sheets. A mechanical design has been developed which presents a practical solution without an umbilical cord. The inspection system has been developed based on client/server architecture. The robot runs a client application and a remote PC executes the server functions. They will both allow any necessary inspections to be performed simultaneously by more than one robot. A sensorial system and a data fusion strategy to estimate the absolute robot position is proposed to allow the robot to navigate autonomously. The graphical monitoring of the robot position in the remote PC (server application) provides the operator with the possibility of controlling the robot, even in situations in which the operator visibility of an area tank is very low or inexistent. Previous experiments have demonstrated the mechanical system's robustness. These experiments consist of robot trajectory measurements and the comparison to a motion kinematic model. I.

BMC Bioinformatics, 2009

Background Microarray technology is so expensive and powerful that it is essential to extract max... more Background Microarray technology is so expensive and powerful that it is essential to extract maximum value from microarray data, specially from large-sample-series microarrays. Our web tools attempt to respond to these researchers' needs by facilitating the possibility to test and formulate from a hypothesis to entire models under a holistic point of view. Results PCOPGene-Net is a web application for facilitating the study of the relationships among gene expressions under microarray conditions, to classify these conditions and to study their effect on expression relationships. Furthermore, the system guides the researcher in the navigation through the microarray data by providing the most suitable genes and information for the researcher's interests at each moment. We achieve all of these by means of the zoom-out operation, the zoom-in operation, the non-continuous analysis and crossing the PCOPGene results with external data-servers. Conclusion PCOPGene-Net helps to ident...

The American Journal of Cardiology, 2011

... Giovanni La Canna MD a , Corresponding Author Contact Information , E-mail The Corresponding ... more ... Giovanni La Canna MD a , Corresponding Author Contact Information , E-mail The Corresponding Author , Iryna Arendar MD a , Francesco Maisano MD b , Fabrizio Monaco MD a , Egidio Collu MD a , Stefano Benussi MD b , Michele De Bonis MD b , Alessandro Castiglioni MD ...

Economic Geology, 1951

Electrical earth resistivity surveys, extensive test drilling, and the electric logging of boring... more Electrical earth resistivity surveys, extensive test drilling, and the electric logging of borings near Champaign-Urbana have provided abundant information for geological study of glacial drift aquifers. This investigation makes possible and encourages an efficient development of the available groundwater resources for public, industrial, and domestic use throughout a three-hundred-square-mile area. The basic geology of the bedrock surface and of the overlying Kansan, Illinoian, and Wisconsin drift mantles is described, together with the techniques of electrical prospecting on the ground surface, electric logging of rotary borings in glacial drift and the collection and study of drift samples. The integration of composite electrical data with geologic studies provides valuable information on the distribution, thickness, permeability, confinement, and origin of scattered water-bearing formations above the bedrock surface. Electrical and geologic cross sections show the regional relations of the aquifers with buried bedrock surface topography which includes the deep Mahomet (Lower Teays) valley. The investigation yields information on numerous water-bearing deposits which are untapped and suitable for extensive industrial exploitation in addition to other aquifers available for municipal and domestic groundwater development. The Champaign-Urbana study-a type investigation reveals the presence of buried sands and gravels whose potential groundwater resources within economic reach of the community greatly exceed total demand for the foreseeable future. INTRODUCTION. Introductory Statement.-The geology of the groundwater resources of the Champaign-Urbana area has been under investigation for more than twenty-five years. This long-term investigation plus a wealth of geological and geophysical data recently acquired is the basis for the present work. Attention is focused on the geologic conditions controlling the occurrence of groundwater in the unconsolidated glacial drift lying above the bedrock. It is the purpose of this paper to describe these geologic conditions and to present some of the geological and geophysical methods used to acquire the basic data. The Champaign-Urbana area, in east-central Illinois, as here defined, is a rectangle fifteen by twenty miles, lying entirely within Champaign County and extending eastward from the Champaign-Piatt county line. It includes parts of twelve townships and contains the following communities in descening order of population : Champaign, Urbana, Mahomet, Bondville, Seymour, Mayview, Deers, Staley, and Sellers. Topography and Drainage.-The land surface is a moderately level to rolling upland prairie with a maximum relief of about 210 feet. The highest elevations lie along the northwest trending Champaign moraine (Fig. 8), between Champaign and Mahomet, called Yankee Ridge. The highest point in the area (approximately 860 feet above sea level) is located in section 20, T.20 N., R.8 E., about six miles northwest of the Champaign city limits. The water sheds of four drainage basins lie within these three hundred square miles. Drainage on the northeast and east is into a west branch of the Vermilion system, and on the south into the headwaters of the Embarrass.

Lecture Notes in Computer Science, 2002

Previous works in Information Retrieval show that using pieces of text obtain better results than... more Previous works in Information Retrieval show that using pieces of text obtain better results than using the whole document as the basic unit to compare with the user's query. This kind of IR systems is usually called Passage Retrieval (PR). This paper discusses the use of our PR system in the question answering process (QA). Our main objective is to examine if a PR system provide a better support for QA than Information Retrieval systems based in the whole document..

Lecture Notes in Computer Science

2008 IEEE Computer Society Conference on Computer Vision and Pattern Recognition Workshops, 2008

Estimating facial pose along a video sequence is an important problem in many applications such a... more Estimating facial pose along a video sequence is an important problem in many applications such as perceptual user interfaces, people monitoring, and aid for the disabled. Currently, most existing methods to compute facial pose are designed to obtain high accuracy under controlled conditions. However, efficiency and robustness are preferable in most practical situations. In this paper, we deal with the problem of 3D pose estimation with the aim to design a fast and approximate solution that requires a minimum amount of information: our method is able to work with just the location of three points-the eyes and the mouth-in each frame. Using that information, and introducing several assumptions-that could hold in many cases-, we show how to estimate the six degrees of freedom of facial position and orientation. Moreover, one single point could be enough after initializing the system. The obtained accuracy greatly depends on the precision of the underlying 2D face tracker. The system is generic and does not require to be trained for each new user.

Transactions in GIS, 2007

We currently have a wealth of geographic information on the Web that is available in different fo... more We currently have a wealth of geographic information on the Web that is available in different forms ranging from images, maps, spatial databases, and tables to simple texts such as informal city guides, description of landscapes, and reports of bird watching activities. One of the most recent initiatives in trying to efficiently index, retrieve, and integrate information on the Web is the Semantic Web (Berners-Lee, Hendler et al. 2001). Berners-Lee's initial example shows the relevance of geographic information: "At the doctor's office, Lucy instructed her Semantic Web agent through her handheld Web browser. The agent promptly retrieved information about Mom's prescribed treatment from the doctor's agent, looked up several lists of providers, and checked for the ones in-plan for Mom's insurance within a 20-mile radius of her home and with a rating of excellent or very good on trusted rating services." This vision will be put in practice with the implementation of software agents that will talk with other agents in order to get the tasks done. For the agents to understand each other it is necessary to have ontologies in place that will define the vocabulary for the agents. For instance, in the example, one agent could have used 'close to', 'near', or 'within walking distance' instead of 'within a 20 miles radius', to achieve similar results. Ontologies provide precise definitions and can be linked to different contexts so that these terms have precise meanings that can be handled by the software agents.

International Journal of Imaging Systems and Technology, 2004

ABSTRACT

This paper introduces a formalization of a set of spatial semantic integrity constraints on an ex... more This paper introduces a formalization of a set of spatial semantic integrity constraints on an extended-relational database model. The formalization extends traditional notions of functional and inclusion dependencies by adding interaction with spatial attributes. This enables to specify implicit and explicit topological conditions between geometries and impose constraints on thematic attributes that depend on the geometries. We study the consistency problem for this set of integrity constraints, which rises issues about topological consistency and realizability of spatial constraints. We show that the consistency problem is not tractable and provide some conditions under which it is.

Lecture Notes in Computer Science

Distributed moving object database servers are a feasible solution to the scalability problem of ... more Distributed moving object database servers are a feasible solution to the scalability problem of centralized database systems. In this paper we propose a distributed indexing method, using the Distributed Hash Table (DHT) paradigm, devised to efficiently support complex spatio temporal queries. We assume a setting in which there is a large number of database servers that keep track of events associated with a highly dynamic system of moving objects deployed in a spatial area. We present a technique for properly keeping the index up to date and efficiently processing range and top-k queries for moving object databases. We evaluated our system using event-driven simulators with demanding spatio temporal workloads and the results show good performance in terms of response time and network traffic.

WebMedia and LA-Web, 2004. Proceedings

This article presents a comparative study of strategies for Web crawling. We show that a combinat... more This article presents a comparative study of strategies for Web crawling. We show that a combination of breadthfirst ordering with the largest sites first is a practical alternative since it is fast, simple to implement, and able to retrieve the best ranked pages at a rate that is closer to the optimal than other alternatives. Our study was performed on a large sample of the Chilean Web which was crawled by using simulators, so that all strategies were compared under the same conditions, and actual crawls to validate our conclusions. We also explored the effects of large scale parallelism in the page retrieval task and multiple-page requests in a single connection for effective amortization of latency times.

Lecture Notes in Computer Science, 2005

This chapter analyzes inconsistency issues in spatial databases. In particular, it reviews types ... more This chapter analyzes inconsistency issues in spatial databases. In particular, it reviews types of inconsistency, specification of integrity constraints, and treatment of inconsistency in multiple representations and data integration. The chapter focuses on inconsistency associated with the geometric representation of objects, spatial relations between objects, and composite objects by aggregation. The main contribution of this paper is a survey of existing approaches to dealing with inconsistency issues in spatial databases that emphasizes the current state of the art and that outlines research issues in the context of inconsistency tolerance. abstraction. At an abstract level, spatial objects can be atomic or complex. Atomic spatial objects are composed of a description and a spatial-component (e.g., a landparcel has a code number and a geometric component represented by a surface), and by aggregation, complex spatial objects are composed of a description and a set of spatial objects (e.g., a sport club may be composed of a sport field, tennis court, gymnasium, and so on). Abstractions that need to be supported in a SDBMS are partitions and networks [37]. A partition represents either a spatial feature or space cell. Partitions are commonly used to represent thematic layers or maps (e.g., soil-type maps and administrative boundaries). A network is seen as a graph embedded in the plane with nodes (e.g., places) that are connected by edges (e.g., highways, rivers, channels, and so on). Other collections of spatial objects that are often relevant to spatial databases are nested partitions (e.g., a country is an aggregation of states and a state is an aggregation of counties) and triangular irregular networks (TIN) (e.g., terrain digital models). Applications of spatial information, in particular geospatial applications, differ from traditional data applications for the following reasons [65]:

Lecture Notes in Computer Science, 2006

Querying about the time-varying locations of moving objects is particularly cumbersome in environ... more Querying about the time-varying locations of moving objects is particularly cumbersome in environments composed of a very large number of distributed spatio temporal database servers. In particular, searching for a specific object can require to visit each server. In this paper we propose a strategy to avoid such an exhaustive search that is based on the use of a centralized index, called meta-index, which is the entry point for spatio-temporal search queries. This index allows a software agent to determine a search plan for visiting the most likely servers to contain the target object. An important issue for large and dynamic distributed servers systems is to keep the meta-index as up-todate as possible with the real system. This paper defines and compares two different strategies for maintaining properly updated the meta-index: crawling, where the centralized system that keeps the index controls itself the updating process, and harvesting, where each distributed database server autonomously transfers data directly into the central index system. Both strategies were implemented and compared by using discrete-event simulators with demanding synthetic spatio-temporal data. The results show that crawling has better performance.

Proceedings of the 2005 international workshop on Geographic information systems - GIS '05, 2005

This paper describes a new spatio-temporal access method (SEST-Index) that combines two approache... more This paper describes a new spatio-temporal access method (SEST-Index) that combines two approaches for modeling spatio-temporal information: snapshots and events. This method makes it possible to not only process time slice and interval queries, but also queries about events. The SEST-Index implementation uses an R-tree structure for storing snapshots and a log data structure for storing events that occur between consecutive snapshots. Experimental results that compare SEST-Index and HR-tree show that, for a change frequency between 1% and 13%, SEST-Index requires less storage space than HR-tree, and for a change frequency between 1% and 7%, SEST-Index outperforms HR-tree for interval queries. In addition, as SEST-Index is an event-oriented structure, event queries are efficiently answered. In order to decrease the storage space for frequencies of change above 20%, this work explores alternatives that optimize the space of the log structure without affecting the efficiency of query answers.

Advances in Spatial Data Handling, 2002

The description of spatial configurations plays a fundamental role in content-based retrieval and... more The description of spatial configurations plays a fundamental role in content-based retrieval and in the design of user interfaces, as this description is often the basis for the specification of query constraints. In this paper we present measures that capture the content description of spatial configurations as quantitative values that reflect characteristics of individual objects and relations among objects. These content measures are evaluated in terms of their ability to distinguish topological relations, and they are used to compare spatial configurations. Such content measures are suitable for similarity-based retrieval and indexing schemas of spatial configurations.

arXiv (Cornell University), Nov 30, 2021

Kulkarni et al. UVEX is a proposed medium class Explorer mission designed to provide crucial miss... more Kulkarni et al. UVEX is a proposed medium class Explorer mission designed to provide crucial missing capabilities that will address objectives central to a broad range of modern astrophysics. The UVEX design has two co-aligned wide-field imagers operating in the FUV and NUV and a powerful broad band medium resolution spectrometer. In its two-year baseline mission, UVEX will perform a multi-cadence synoptic all-sky survey 50/100 times deeper than GALEX in the near/far ultraviolet, cadenced surveys of the Large and Small Magellanic Clouds, rapid target of opportunity follow-up, as well as spectroscopic followup of samples of stars and galaxies. The science program is built around three pillars. First, UVEX will explore the low-mass, low-metallicity galaxy frontier through imaging and spectroscopic surveys that will probe key aspects of the evolution of galaxies by understanding how star formation and stellar evolution at low metallicities affect the growth and evolution of low-metallicity, low-mass galaxies in the local universe. Such galaxies contain half the mass in the local universe, and are analogs for the first galaxies, but observed at distances that make them accessible to detailed study. Second, UVEX will explore the dynamic universe through time-domain surveys and prompt spectroscopic followup capability will probe the environments, energetics, and emission processes in the early aftermaths of gravitational wave-discovered compact object mergers, discover hot, fast UV transients, and diagnose the early stages of stellar explosions. Finally, UVEX will become a key community resource by leaving a large all-sky legacy data set, enabling a wide range of scientific studies and filling a gap in the new generation of wide-field, sensitive optical and infrared surveys provided by the Rubin, Euclid , and Roman observatories. This paper discusses the scientific potential of UVEX , and the broad scientific program.

Research Notes of the AAS, 2022

Tumer et al. 2022, ATel #15171) have recently reported the discovery of an X-ray source, NuSTAR J... more Tumer et al. 2022, ATel #15171) have recently reported the discovery of an X-ray source, NuSTAR J053449+2126.0, during a calibration observation which took place on 25 April 2020. We scan the Zwicky Transient Facility (ZTF) alerts and archival photometry to determine the nature of the source. Palomar Gattini-IR is searched as well. We identify no obvious counterpart candidate. Follow-up X-ray and optical studies are needed to determine the true counterpart.

The Astrophysical Journal, 2022

We apply a conventional accretion disk model to the FU Ori–type objects HBC 722 and Gaia 17bpi. O... more We apply a conventional accretion disk model to the FU Ori–type objects HBC 722 and Gaia 17bpi. Our base model is a steady-state, thin Keplerian disk featuring a modified Shakura–Sunyaev temperature profile, with each annulus radiating as an area-weighted spectrum given by a NextGen atmosphere at the appropriate temperature. We explore departures from the standard model by altering the temperature distribution in the innermost region of the disk to account for “boundary region”–like effects. We consider the overall spectral energy distribution as well as medium- and high-resolution spectra in evaluating best-fit models to the data. Parameter degeneracies are studied via a Markov Chain Monte Carlo parameter estimation technique. Allowing all parameters to vary, we find accretion rates for HBC 722 of M ̇ = 10 − 4.90 M ⊙ yr − 1 − 0.40 + 0.99 dex and for Gaia 17bpi of M ̇ = 10 − 6.70 M ⊙ yr − 1 − 0.36 + 0.46 dex ; the corresponding maximum disk temperatures are 7100 − 500 + 300 K and 79...

Botanical Sciences, 2017

Background. Abiotic constraints, historical effects of the last glaciation, and differential disp... more Background. Abiotic constraints, historical effects of the last glaciation, and differential dispersal, have been proposed as potential explanations to account for the latitudinal decrease in acorn size of wide-ranging oak species distributed in the U.S. and Canada. Hypothesis. We specifically tested the abiotic constraints hypothesis on oak acorn size in a geographical area without the counfounding influence of glaciation and related dispersal history. Data description. Acorns from seven populations of the white oak Quercus rugosa were collected, encompassing the distribution of the species in Mexico. Study site and years of study. Mexico, 2009-2010. Results. Acorn length, width, mass and volume differed significantly among populations and indicated a marked clinal latitudinal reduction in acorn size. A multiple regression model revealed that this reduction in size (measured as acorn volume) can be explained by two important bioclimatic variables (growing season precipitation and g...

IECON 2010 - 36th Annual Conference on IEEE Industrial Electronics Society, 2010

This paper describes a solution to a mobile climbing robot on magnetic wheels, designed for inspe... more This paper describes a solution to a mobile climbing robot on magnetic wheels, designed for inspecting exterior oil tank surfaces made of metal sheets. A mechanical design has been developed which presents a practical solution without an umbilical cord. The inspection system has been developed based on client/server architecture. The robot runs a client application and a remote PC executes the server functions. They will both allow any necessary inspections to be performed simultaneously by more than one robot. A sensorial system and a data fusion strategy to estimate the absolute robot position is proposed to allow the robot to navigate autonomously. The graphical monitoring of the robot position in the remote PC (server application) provides the operator with the possibility of controlling the robot, even in situations in which the operator visibility of an area tank is very low or inexistent. Previous experiments have demonstrated the mechanical system's robustness. These experiments consist of robot trajectory measurements and the comparison to a motion kinematic model. I.

BMC Bioinformatics, 2009

Background Microarray technology is so expensive and powerful that it is essential to extract max... more Background Microarray technology is so expensive and powerful that it is essential to extract maximum value from microarray data, specially from large-sample-series microarrays. Our web tools attempt to respond to these researchers' needs by facilitating the possibility to test and formulate from a hypothesis to entire models under a holistic point of view. Results PCOPGene-Net is a web application for facilitating the study of the relationships among gene expressions under microarray conditions, to classify these conditions and to study their effect on expression relationships. Furthermore, the system guides the researcher in the navigation through the microarray data by providing the most suitable genes and information for the researcher's interests at each moment. We achieve all of these by means of the zoom-out operation, the zoom-in operation, the non-continuous analysis and crossing the PCOPGene results with external data-servers. Conclusion PCOPGene-Net helps to ident...

The American Journal of Cardiology, 2011

... Giovanni La Canna MD a , Corresponding Author Contact Information , E-mail The Corresponding ... more ... Giovanni La Canna MD a , Corresponding Author Contact Information , E-mail The Corresponding Author , Iryna Arendar MD a , Francesco Maisano MD b , Fabrizio Monaco MD a , Egidio Collu MD a , Stefano Benussi MD b , Michele De Bonis MD b , Alessandro Castiglioni MD ...

Economic Geology, 1951

Electrical earth resistivity surveys, extensive test drilling, and the electric logging of boring... more Electrical earth resistivity surveys, extensive test drilling, and the electric logging of borings near Champaign-Urbana have provided abundant information for geological study of glacial drift aquifers. This investigation makes possible and encourages an efficient development of the available groundwater resources for public, industrial, and domestic use throughout a three-hundred-square-mile area. The basic geology of the bedrock surface and of the overlying Kansan, Illinoian, and Wisconsin drift mantles is described, together with the techniques of electrical prospecting on the ground surface, electric logging of rotary borings in glacial drift and the collection and study of drift samples. The integration of composite electrical data with geologic studies provides valuable information on the distribution, thickness, permeability, confinement, and origin of scattered water-bearing formations above the bedrock surface. Electrical and geologic cross sections show the regional relations of the aquifers with buried bedrock surface topography which includes the deep Mahomet (Lower Teays) valley. The investigation yields information on numerous water-bearing deposits which are untapped and suitable for extensive industrial exploitation in addition to other aquifers available for municipal and domestic groundwater development. The Champaign-Urbana study-a type investigation reveals the presence of buried sands and gravels whose potential groundwater resources within economic reach of the community greatly exceed total demand for the foreseeable future. INTRODUCTION. Introductory Statement.-The geology of the groundwater resources of the Champaign-Urbana area has been under investigation for more than twenty-five years. This long-term investigation plus a wealth of geological and geophysical data recently acquired is the basis for the present work. Attention is focused on the geologic conditions controlling the occurrence of groundwater in the unconsolidated glacial drift lying above the bedrock. It is the purpose of this paper to describe these geologic conditions and to present some of the geological and geophysical methods used to acquire the basic data. The Champaign-Urbana area, in east-central Illinois, as here defined, is a rectangle fifteen by twenty miles, lying entirely within Champaign County and extending eastward from the Champaign-Piatt county line. It includes parts of twelve townships and contains the following communities in descening order of population : Champaign, Urbana, Mahomet, Bondville, Seymour, Mayview, Deers, Staley, and Sellers. Topography and Drainage.-The land surface is a moderately level to rolling upland prairie with a maximum relief of about 210 feet. The highest elevations lie along the northwest trending Champaign moraine (Fig. 8), between Champaign and Mahomet, called Yankee Ridge. The highest point in the area (approximately 860 feet above sea level) is located in section 20, T.20 N., R.8 E., about six miles northwest of the Champaign city limits. The water sheds of four drainage basins lie within these three hundred square miles. Drainage on the northeast and east is into a west branch of the Vermilion system, and on the south into the headwaters of the Embarrass.

Lecture Notes in Computer Science, 2002

Previous works in Information Retrieval show that using pieces of text obtain better results than... more Previous works in Information Retrieval show that using pieces of text obtain better results than using the whole document as the basic unit to compare with the user's query. This kind of IR systems is usually called Passage Retrieval (PR). This paper discusses the use of our PR system in the question answering process (QA). Our main objective is to examine if a PR system provide a better support for QA than Information Retrieval systems based in the whole document..

Lecture Notes in Computer Science

2008 IEEE Computer Society Conference on Computer Vision and Pattern Recognition Workshops, 2008

Estimating facial pose along a video sequence is an important problem in many applications such a... more Estimating facial pose along a video sequence is an important problem in many applications such as perceptual user interfaces, people monitoring, and aid for the disabled. Currently, most existing methods to compute facial pose are designed to obtain high accuracy under controlled conditions. However, efficiency and robustness are preferable in most practical situations. In this paper, we deal with the problem of 3D pose estimation with the aim to design a fast and approximate solution that requires a minimum amount of information: our method is able to work with just the location of three points-the eyes and the mouth-in each frame. Using that information, and introducing several assumptions-that could hold in many cases-, we show how to estimate the six degrees of freedom of facial position and orientation. Moreover, one single point could be enough after initializing the system. The obtained accuracy greatly depends on the precision of the underlying 2D face tracker. The system is generic and does not require to be trained for each new user.

Transactions in GIS, 2007

We currently have a wealth of geographic information on the Web that is available in different fo... more We currently have a wealth of geographic information on the Web that is available in different forms ranging from images, maps, spatial databases, and tables to simple texts such as informal city guides, description of landscapes, and reports of bird watching activities. One of the most recent initiatives in trying to efficiently index, retrieve, and integrate information on the Web is the Semantic Web (Berners-Lee, Hendler et al. 2001). Berners-Lee's initial example shows the relevance of geographic information: "At the doctor's office, Lucy instructed her Semantic Web agent through her handheld Web browser. The agent promptly retrieved information about Mom's prescribed treatment from the doctor's agent, looked up several lists of providers, and checked for the ones in-plan for Mom's insurance within a 20-mile radius of her home and with a rating of excellent or very good on trusted rating services." This vision will be put in practice with the implementation of software agents that will talk with other agents in order to get the tasks done. For the agents to understand each other it is necessary to have ontologies in place that will define the vocabulary for the agents. For instance, in the example, one agent could have used 'close to', 'near', or 'within walking distance' instead of 'within a 20 miles radius', to achieve similar results. Ontologies provide precise definitions and can be linked to different contexts so that these terms have precise meanings that can be handled by the software agents.

International Journal of Imaging Systems and Technology, 2004

ABSTRACT

This paper introduces a formalization of a set of spatial semantic integrity constraints on an ex... more This paper introduces a formalization of a set of spatial semantic integrity constraints on an extended-relational database model. The formalization extends traditional notions of functional and inclusion dependencies by adding interaction with spatial attributes. This enables to specify implicit and explicit topological conditions between geometries and impose constraints on thematic attributes that depend on the geometries. We study the consistency problem for this set of integrity constraints, which rises issues about topological consistency and realizability of spatial constraints. We show that the consistency problem is not tractable and provide some conditions under which it is.

Lecture Notes in Computer Science

Distributed moving object database servers are a feasible solution to the scalability problem of ... more Distributed moving object database servers are a feasible solution to the scalability problem of centralized database systems. In this paper we propose a distributed indexing method, using the Distributed Hash Table (DHT) paradigm, devised to efficiently support complex spatio temporal queries. We assume a setting in which there is a large number of database servers that keep track of events associated with a highly dynamic system of moving objects deployed in a spatial area. We present a technique for properly keeping the index up to date and efficiently processing range and top-k queries for moving object databases. We evaluated our system using event-driven simulators with demanding spatio temporal workloads and the results show good performance in terms of response time and network traffic.

WebMedia and LA-Web, 2004. Proceedings

This article presents a comparative study of strategies for Web crawling. We show that a combinat... more This article presents a comparative study of strategies for Web crawling. We show that a combination of breadthfirst ordering with the largest sites first is a practical alternative since it is fast, simple to implement, and able to retrieve the best ranked pages at a rate that is closer to the optimal than other alternatives. Our study was performed on a large sample of the Chilean Web which was crawled by using simulators, so that all strategies were compared under the same conditions, and actual crawls to validate our conclusions. We also explored the effects of large scale parallelism in the page retrieval task and multiple-page requests in a single connection for effective amortization of latency times.

Lecture Notes in Computer Science, 2005

This chapter analyzes inconsistency issues in spatial databases. In particular, it reviews types ... more This chapter analyzes inconsistency issues in spatial databases. In particular, it reviews types of inconsistency, specification of integrity constraints, and treatment of inconsistency in multiple representations and data integration. The chapter focuses on inconsistency associated with the geometric representation of objects, spatial relations between objects, and composite objects by aggregation. The main contribution of this paper is a survey of existing approaches to dealing with inconsistency issues in spatial databases that emphasizes the current state of the art and that outlines research issues in the context of inconsistency tolerance. abstraction. At an abstract level, spatial objects can be atomic or complex. Atomic spatial objects are composed of a description and a spatial-component (e.g., a landparcel has a code number and a geometric component represented by a surface), and by aggregation, complex spatial objects are composed of a description and a set of spatial objects (e.g., a sport club may be composed of a sport field, tennis court, gymnasium, and so on). Abstractions that need to be supported in a SDBMS are partitions and networks [37]. A partition represents either a spatial feature or space cell. Partitions are commonly used to represent thematic layers or maps (e.g., soil-type maps and administrative boundaries). A network is seen as a graph embedded in the plane with nodes (e.g., places) that are connected by edges (e.g., highways, rivers, channels, and so on). Other collections of spatial objects that are often relevant to spatial databases are nested partitions (e.g., a country is an aggregation of states and a state is an aggregation of counties) and triangular irregular networks (TIN) (e.g., terrain digital models). Applications of spatial information, in particular geospatial applications, differ from traditional data applications for the following reasons [65]:

Lecture Notes in Computer Science, 2006

Querying about the time-varying locations of moving objects is particularly cumbersome in environ... more Querying about the time-varying locations of moving objects is particularly cumbersome in environments composed of a very large number of distributed spatio temporal database servers. In particular, searching for a specific object can require to visit each server. In this paper we propose a strategy to avoid such an exhaustive search that is based on the use of a centralized index, called meta-index, which is the entry point for spatio-temporal search queries. This index allows a software agent to determine a search plan for visiting the most likely servers to contain the target object. An important issue for large and dynamic distributed servers systems is to keep the meta-index as up-todate as possible with the real system. This paper defines and compares two different strategies for maintaining properly updated the meta-index: crawling, where the centralized system that keeps the index controls itself the updating process, and harvesting, where each distributed database server autonomously transfers data directly into the central index system. Both strategies were implemented and compared by using discrete-event simulators with demanding synthetic spatio-temporal data. The results show that crawling has better performance.

Proceedings of the 2005 international workshop on Geographic information systems - GIS '05, 2005

This paper describes a new spatio-temporal access method (SEST-Index) that combines two approache... more This paper describes a new spatio-temporal access method (SEST-Index) that combines two approaches for modeling spatio-temporal information: snapshots and events. This method makes it possible to not only process time slice and interval queries, but also queries about events. The SEST-Index implementation uses an R-tree structure for storing snapshots and a log data structure for storing events that occur between consecutive snapshots. Experimental results that compare SEST-Index and HR-tree show that, for a change frequency between 1% and 13%, SEST-Index requires less storage space than HR-tree, and for a change frequency between 1% and 7%, SEST-Index outperforms HR-tree for interval queries. In addition, as SEST-Index is an event-oriented structure, event queries are efficiently answered. In order to decrease the storage space for frequencies of change above 20%, this work explores alternatives that optimize the space of the log structure without affecting the efficiency of query answers.

Advances in Spatial Data Handling, 2002

The description of spatial configurations plays a fundamental role in content-based retrieval and... more The description of spatial configurations plays a fundamental role in content-based retrieval and in the design of user interfaces, as this description is often the basis for the specification of query constraints. In this paper we present measures that capture the content description of spatial configurations as quantitative values that reflect characteristics of individual objects and relations among objects. These content measures are evaluated in terms of their ability to distinguish topological relations, and they are used to compare spatial configurations. Such content measures are suitable for similarity-based retrieval and indexing schemas of spatial configurations.