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Displaying 1-50 out of 134 total
Neighbor Selection and Weighting in User-Based Collaborative Filtering: A Performance Prediction Approach
Found in: ACM Transactions on the Web (TWEB)
By Alejandro Bellogín, Iván Cantador, Pablo Castells
Issue Date:March 2014
pp. 1-30
User-based collaborative filtering systems suggest interesting items to a user relying on similar-minded people called neighbors. The selection and weighting of these neighbors characterize the different recommendation approaches. While standard strategies...
     
Robust glint detection through homography normalization
Found in: Proceedings of the Symposium on Eye Tracking Research and Applications (ETRA '14)
By Dan Witzner Hansen, Iván García Ferreiros, Lars Roholm
Issue Date:March 2014
pp. 91-94
A novel normalization principle for robust glint detection is presented. The method is based on geometric properties of corneal reflections and allows for simple and effective detection of glints even in the presence of several spurious and identically app...
     
A generative computer language to customize online learning assessments
Found in: Proceedings of the First International Conference on Technological Ecosystem for Enhancing Multiculturality (TEEM '13)
By Antonio Balderas, Juan M. Dodero, Manuel Palomo-Duarte, Iván Ruiz-Rube
Issue Date:November 2013
pp. 141-147
The focus on assessment of learning experiences has shifted from knowledge to competences. Unfortunately, assessing certain competences is mainly a subjective task, being problematic for both the evaluators and the evaluated. Additionally, when the learnin...
     
Solving the compressible navier-stokes equations on up to 1.97 million cores and 4.1 trillion grid points
Found in: Proceedings of SC13: International Conference for High Performance Computing, Networking, Storage and Analysis (SC '13)
By Blaise M. Barney, Johan Larsson, Julien Bodart, Steve Jones, Iván Bermejo-Moreno, Joseph W. Nichols
Issue Date:November 2013
pp. 1-10
We present weak and strong scaling studies as well as performance analyses of the Hybrid code, a finite-difference solver of the compressible Navier-Stokes equations on structured grids used for the direct numerical simulation of isotropic turbulence and i...
     
Modeling instrumental activities of daily living in egocentric vision as sequences of active objects and context for alzheimer disease research
Found in: Proceedings of the 1st ACM international workshop on Multimedia indexing and information retrieval for healthcare (MIIRH '13)
By Guillaume Bourmaud, Iván González Díaz, Jenny Benois-Pineau, Rémi Megret, Vincent Buso
Issue Date:October 2013
pp. 11-14
In this paper we study the problem of recognizing Instrumental Activities of Daily Living (IADL) in egocentric camera view. The target application of this research is the indexing of videos of patients with Alzehimer disease, thus providing medical staff w...
     
Collaborative data sharing via update exchange and provenance
Found in: ACM Transactions on Database Systems (TODS)
By Grigoris Karvounarakis, Todd J. Green, Val Tannen, Zachary G. Ives
Issue Date:August 2013
pp. 1-42
Recent work [Ives et al. 2005] proposed a new class of systems for supporting data sharing among scientific and other collaborations: this new collaborative data sharing system connects heterogeneous logical peers using a network of schema mappings. Each p...
     
Composing graphical languages
Found in: Proceedings of the First Workshop on the Globalization of Domain Specific Languages (GlobalDSL '13)
By Iván Melo, Jorge Villalobos, Mario Sánchez
Issue Date:July 2013
pp. 12-17
As domain-specific modeling languages, and especially graphical modeling languages become more and more widespread, so do workbenches for generating editors and tools to use said languages. The advantages of these languages depend heavily on their expressi...
     
Open data framework for sustainable assessment in software forges
Found in: Proceedings of the 3rd International Conference on Web Intelligence, Mining and Semantics (WIMS '13)
By Ignacio Traverso-Ribón, Iván Ruíz-Rube, Juan Manuel Dodero, Manuel Palomo-Duarte
Issue Date:June 2013
pp. 1-8
In a project-based learning experience, the detailed monitoring of the activities in which team members participate can be useful to evaluate their work. Using learning-oriented assessment procedures, supervisors can assess the teamwork abilities with a fo...
     
Exploiting time contexts in collaborative filtering: an item splitting approach
Found in: Proceedings of the 3rd Workshop on Context-awareness in Retrieval and Recommendation (CaRR '13)
By Fernando Díez, Iván Cantador, Pedro G. Campos
Issue Date:February 2013
pp. 3-6
Item Splitting has been proposed as a technique for improving Collaborative Filtering (CF) by means of grouping and exploiting ratings according to the contexts in which they were generated. It shows positive effects on recommendation in the presence of si...
     
Inference of the Genetic Network Regulating Lateral Root Initiation in Arabidopsis thaliana
Found in: IEEE/ACM Transactions on Computational Biology and Bioinformatics (TCBB)
By Charlie Hodgman, Daniele Muraro, Helen Byrne, Ive De Smet, John King, Malcolm Bennett, Michael Wilson, Ute Vob
Issue Date:January 2013
pp. 50-60
Regulation of gene expression is crucial for organism growth, and it is one of the challenges in systems biology to reconstruct the underlying regulatory biological networks from transcriptomic data. The formation of lateral roots in Arabidopsis thaliana i...
     
An empirical comparison of social, collaborative filtering, and hybrid recommenders
Found in: ACM Transactions on Intelligent Systems and Technology (TIST)
By Alejandro Bellogín, Enrique Chavarriaga, Fernando Díez, Iván Cantador, Pablo Castells
Issue Date:January 2013
pp. 1-29
In the Social Web, a number of diverse recommendation approaches have been proposed to exploit the user generated contents available in the Web, such as rating, tagging, and social networking information. In general, these approaches naturally require the ...
     
Workshop on multimodal crowd sensing (CrowdSens 2012)
Found in: Proceedings of the 21st ACM international conference on Information and knowledge management (CIKM '12)
By Haggai Roitman, Iván Cantador, Miriam Fernández
Issue Date:October 2012
pp. 2770-2771
This paper provides an overview of the 1st International Workshop on Multimodal Crowd Sensing (CrowdSens 2012), held at the 21st ACM International Conference on Information and Knowledge Management (CIKM 2012). This workshop aimed to provide an open forum ...
     
Time feature selection for identifying active household members
Found in: Proceedings of the 21st ACM international conference on Information and knowledge management (CIKM '12)
By Alejandro Bellogin, Fernando Díez, Iván Cantador, Pedro G. Campos
Issue Date:October 2012
pp. 2311-2314
Popular online rental services such as Netflix and MoviePilot often manage household accounts. A household account is usually shared by various users who live in the same house, but in general does not provide a mechanism by which current active users are ...
     
User interaction analysis in a CSCL environment supported by social media technologies
Found in: Proceedings of the 13th International Conference on Interaccin Persona-Ordenador (INTERACCION '12)
By Iván D. Claros, Ruth Cobos
Issue Date:October 2012
pp. 1-2
This paper presents a description of a collaborative learning environment for the composition of educational multimedia objects, called SMLearning. This environment was built with social media technologies and evaluated through a blended learning experienc...
     
Introduction to the Special Section on Search and Mining User-Generated Content
Found in: ACM Transactions on Intelligent Systems and Technology (TIST)
By Francisco Carrero, Iván Cantador, José Antonio Troyano, José Carlos Cortizo, Paolo Rosso
Issue Date:September 2012
pp. 1-3
The primary goal of this special section of ACM Transactions on Intelligent Systems and Technology is to foster research in the interplay between Social Media, Data/Opinion Mining and Search, aiming to reflect the actual developments in technologies that e...
     
Real Time Iris Segmentation on FPGA
Found in: 2012 IEEE 23rd International Conference on Application-specific Systems, Architectures and Processors (ASAP)
By Hau Ngo,Jennifer Shafer,Robert Ives,Ryan Rakvic,Randy Broussard
Issue Date:July 2012
pp. 1-7
In this paper, a real time FPGA-based iris segmentation system is presented. The segmentation method implements  the Canny edge detection algorithm and a circle search to detect an iris in an image or video frame. The proposed high performance architecture...
 
Building a data governance model for learning analytics
Found in: Proceedings of the 2nd International Conference on Learning Analytics and Knowledge (LAK '12)
By Cindy Ives, Doug Clow, Lori Lockyer, Paul Hobson, Sabine Graf
Issue Date:April 2012
pp. 21-22
This international panel presentation aims to explore and discuss the issues that emerge when an educational institution decides to develop learning analytics initiatives. While learning analytics may provide data that lead to improvements in the quality o...
     
Recomputing Materialized Instances after Changes to Mappings and Data
Found in: Data Engineering, International Conference on
By Todd J. Green,Zachary G. Ives
Issue Date:April 2012
pp. 330-341
A major challenge faced by today's information systems is that of evolution as data usage evolves or new data resources become available. Modern organizations sometimes exchange data with one another via declarative mappings among their databases, as in da...
 
Evaluating the information content of near-infrared iris imagery
Found in: Proceedings of the 4th International Symposium on Applied Sciences in Biomedical and Communication Technologies (ISABEL '11)
By Hau Ngo, Robert W. Ives, Stephen Winchell
Issue Date:October 2011
pp. 1-5
The human iris exhibits random and unique textural patterns that allow for identification with high accuracy. These patterns are evident in near-infrared (NIR) imagery, even for very dark irises. The authors investigate the information content of the iris ...
     
NetTrails: a declarative platform for maintaining and querying provenance in distributed systems
Found in: Proceedings of the 2011 international conference on Management of data (SIGMOD '11)
By Andreas Haeberlen, Boon Thau Loo, Micah Sherr, Qiong Fei, Shengzhi Sun, Tao Tao, Wenchao Zhou, Zachary Ives
Issue Date:June 2011
pp. 1323-1326
We demonstrate NetTrails, a declarative platform for maintaining and interactively querying network provenance in a distributed system. Network provenance describes the history and derivations of network state that result from the execution of a distribute...
     
Sharing work in keyword search over databases
Found in: Proceedings of the 2011 international conference on Management of data (SIGMOD '11)
By Marie Jacob, Zachary Ives
Issue Date:June 2011
pp. 577-588
An important means of allowing non-expert end-users to pose ad hoc queries whether over single databases or data integration systems is through keyword search. Given a set of keywords, the query processor finds matches across different tuples and tables. I...
     
AAT: a tool for accessing and analysing students' behaviour data in learning systems
Found in: Proceedings of the 1st International Conference on Learning Analytics and Knowledge (LAK '11)
By Arnold Ferri, Cindy Ives, Nazim Rahman, Sabine Graf
Issue Date:February 2011
pp. 174-179
In online learning environments, teachers and course designers often get little feedback about how students actually interact with and learn in online courses. Most of the learning systems used by educational institutions store comprehensive log data assoc...
     
Heat transfer integration with Beam Optics Analyzer
Found in: IEEE International Vacuum Electronics Conference
By Thuc Bui, Lawrence Ives, Michael Read
Issue Date:February 2011
pp. 67
This paper will describe the new capability in BOA, the heat transfer integration with particle simulations. It will discuss implemented techniques to smooth the wall power density field generated by electron energy. It will explain the finite element meth...
 
Development of a 402.5 MHz 140 kW Inductive Output Tube
Found in: IEEE International Vacuum Electronics Conference
By Michael Read, Thuc Bui, Robert Jackson, Lawrence Ives, Henry Freund
Issue Date:February 2011
pp. 273-274
This paper describes a 402.5 MHz 140 kW Inductive Output Tube (IOT) that is being developed for use in proton accelerators. New, more efficient, computer codes will be used to simulate the time dependent behavior of the IOT. The principal components of the...
 
Development of a 100 kW CW, S-Band, PPM focused klystron
Found in: IEEE International Vacuum Electronics Conference
By Patrick Ferguson, Michael E. Read, David Marsden, R. Lawrence Ives
Issue Date:February 2011
pp. 301-302
This paper describes a 100 kW CW, S-Band klystron that is being developed for use in high energy accelerator applications. Focusing for the beam is provided by a PPM structure. The principal components of the device, including the RF structure, electron gu...
 
2 MW CW RF load for gyrotrons
Found in: IEEE International Vacuum Electronics Conference
By R. Lawrence Ives, David Marsden, Max Mizuhara, George Collins, Jeff Neilson, Philipp Borchard
Issue Date:February 2011
pp. 403-404
Final design and assembly are in progress for a 2 MW CW RF load for gyrotrons. Such loads are required for testing high power gyrotrons for electron cyclotron heating of fusion plasmas. The research is building on experience with a 1 MW load to increase th...
 
High current density reservoir cathode development
Found in: IEEE International Vacuum Electronics Conference
By R. Lawrence Ives, George Collins, David Marsden, George Miram, Louis R. Falce
Issue Date:February 2011
pp. 35-36
Research is continuing in development of high current density, reservoir cathodes. The research is focused on investigating different reservoir materials and applications. An additional goal is to increase the current density capability and further extend ...
 
Minimization of effects of backscattered electrons in gyrotrons with depressed collectors
Found in: IEEE International Vacuum Electronics Conference
By Amarjit Singh, William B. Herrmannsfeldt, R. Lawrence Ives
Issue Date:February 2011
pp. 115-116
Gyrotron performance can be adversely affected by electrons backscattered from the collector and travelling back to the rf cavity and beyond. They can cause deposition of excessive heat in sensitive areas, and enter high field cavities, causing breakdown o...
 
Temporal particle-in-cell analysis in Beam Optics Analyzer
Found in: IEEE International Vacuum Electronics Conference
By Thuc Bui, Michael Read, Lawrence Ives
Issue Date:February 2011
pp. 179
This paper will describe the new feature, temporal particle-in-cell analysis in Beam Optics Analyzer in detail. Algorithms for pushing particles and field solution will be discussed. Numerical results for a diode as well as a gridded electron gun will demo...
 
A 350 MHz, 200 kW CW, multiple beam IOT
Found in: IEEE International Vacuum Electronics Conference
By Lawrence Ives, Michael Read, David Marsden, R. H. Jackson, Thuc Bui, Takuji Kimura, Edward Eisen
Issue Date:February 2011
pp. 319-320
Design is complete and fabrication and assembly are nearing completion on a 350 MHz, 200 kW CW, multiple beam inductive output tube (MBIOT). Seven electron guns in a circular array will be driven by a single input cavity. RF power is generated in a single,...
 
A Flexible Mechanism for Providing Adaptivity Based on Learning Styles in Learning Management Systems
Found in: Advanced Learning Technologies, IEEE International Conference on
By Sabine Graf, Kinshuk, Cindy Ives
Issue Date:July 2010
pp. 30-34
While today’s learning management systems (LMSs) provide lot of support for teachers to assist them in holding online courses, they typically do not consider students’ individual differences in the composition and structure of courses. In this paper, we in...
 
Maintaining Recursive Views of Regions and Connectivity in Networks
Found in: IEEE Transactions on Knowledge and Data Engineering
By Mengmeng Liu, Nicholas E. Taylor, Wenchao Zhou, Zachary G. Ives, Boon Thau Loo
Issue Date:August 2010
pp. 1126-1141
The data management community has recently begun to consider declarative network routing and distributed acquisition: e.g., sensor networks that execute queries about contiguous regions, declarative networks that maintain shortest paths, and distributed an...
 
Reliable storage and querying for collaborative data sharing systems
Found in: Data Engineering, International Conference on
By Nicholas E. Taylor, Zachary G. Ives
Issue Date:March 2010
pp. 40-51
The sciences, business confederations, and medicine urgently need infrastructure for sharing data and updates among collaborators' constantly changing, heterogeneous databases. The ORCHESTRA system addresses these needs by providing data transformation and...
 
FPGA or Cell for an Image Processing Application
Found in: Advances in Computing, Control, and Telecommunication Technologies, International Conference on
By Ryan N. Rakvic, Hau Ngo, Randy P. Broussard, Robert W. Ives
Issue Date:December 2009
pp. 271-274
Modern advancements in configurable hardware, most notably Field-Programmable Gate Arrays (FPGAs) have provided an exciting opportunity to discover the parallel nature of modern image processing algorithms. On the other hand, PlayStation3 (PS3) game consol...
 
Hermite Interpolation of Implicit Surfaces with Radial Basis Functions
Found in: Graphics, Patterns and Images, SIBGRAPI Conference on
By Ives Macêdo, João Paulo Gois, Luiz Velho
Issue Date:October 2009
pp. 1-8
We present the Hermite radial basis function (HRBF) implicits method to compute a global implicit function which interpolates scattered multivariate Hermite data (unstructured points and their corresponding normals). Differently from previous radial basis ...
 
SmartCIS: integrating digital and physical environments
Found in: Proceedings of the 35th SIGMOD international conference on Management of data (SIGMOD '09)
By Boon Thau Loo, Marie Jacob, Mengmeng Liu, Sudipto Guha, Svilen R. Mihaylov, Zachary G. Ives, Zhuowei Bao
Issue Date:June 2009
pp. 3-4
Special-purpose social sites can offer valuable services to well-defined, closed, communities, e.g., in a university or in a corporation. The purpose of this demo is to show the challenges, special features and potential of a focused social system in actio...
     
Reconcilable differences
Found in: Proceedings of the 12th International Conference on Database Theory (ICDT '09)
By Todd J. Green, Val Tannen, Zachary G. Ives
Issue Date:March 2009
pp. 94-104
Exact query reformulation using views in positive relational languages is well understood, and has a variety of applications in query optimization and data sharing. Generalizations to larger fragments of the relational algebra (RA) --- specifically, suppor...
     
Recursive Computation of Regions and Connectivity in Networks
Found in: Data Engineering, International Conference on
By Mengmeng Liu, Nicholas E. Taylor, Wenchao Zhou, Zachary G. Ives, Boon Thau Loo
Issue Date:April 2009
pp. 1108-1119
In recent years, the data management community has begun to consider situations in which data access is closely tied to network routing and distributed acquisition: examples include, sensor networks that execute queries about reachable nodes or contiguous ...
 
MOSAIC: unified declarative platform for dynamic overlay composition
Found in: Proceedings of the 2008 ACM CoNEXT Conference (CONEXT '08)
By Boon Thau Loo, Jonathan M. Smith, Yun Mao, Zachary Ives
Issue Date:December 2008
pp. 1-12
Overlay networks create new networking services across nodes that communicate using pre-existing networks. MOSAIC is a unified declarative platform for constructing new overlay networks from multiple existing overlays, each possessing a subset of the desir...
     
PCA-Based 3D Face Photography
Found in: Graphics, Patterns and Images, SIBGRAPI Conference on
By Jesús P. Mena-Chalco, Ives Macêdo, Luiz Velho, Roberto M. Cesar Jr.
Issue Date:October 2008
pp. 313-320
This paper presents a 3D face photography system based on a small set of training facial range images. The training set is composed by 2D texture and 3D range images (i.e. geometry) of a single subject with different facial expressions. The basic idea behi...
 
A substrate for in-network sensor data integration
Found in: Proceedings of the 5th workshop on Data management for sensor networks (DMSN '08)
By Marie Jacob, Sudipto Guha, Svilen R. Mihaylov, Zachary G. Ives
Issue Date:August 2008
pp. 1-30
With the ultimate goal of extending the data integration paradigm and query processing capabilities to ad hoc wireless networks, sensors, and stream systems, we consider how to support communication between sets of nodes performing distributed joins in sen...
     
Sideways Information Passing for Push-Style Query Processing
Found in: Data Engineering, International Conference on
By Zachary G. Ives, Nicholas E. Taylor
Issue Date:April 2008
pp. 774-783
In many modern data management settings, data is queried from a central node or nodes, but is stored at remote sources. In such a setting it is common to perform
 
A Benchmark Suite for Unstructured Data Processing
Found in: Storage Network Architecture and Parallel I/Os, IEEE International Workshop on
By Clinton Wills Smullen Iv, Shahrukh Rohinton Tarapore, Sudhanva Gurumurthi
Issue Date:September 2007
pp. 79-83
A large fraction of the data that will stored and accessed in future systems is expected to be unstructured, in the form of images, audio files, etc. Therefore, it is very important to design future I/O subsystems to provide efficient storage, and access t...
 
The case for a unified extensible data-centric mobility infrastructure
Found in: Proceedings of first ACM/IEEE international workshop on Mobility in the evolving internet architecture (MobiArch '07)
By Boon Thau Loo, Jonathan M. Smith, Yun Mao, Zachary Ives
Issue Date:August 2007
pp. 1-21
We present a unified, extensible data-centric mobility infrastructure based on declarative networks and composable distributed views over network, router, and host state. Declarative networks are a recent innovation for building extensible network architec...
     
ORCHESTRA: facilitating collaborative data sharing
Found in: Proceedings of the 2007 ACM SIGMOD international conference on Management of data (SIGMOD '07)
By Grigoris Karvounarakis, Nicholas E. Taylor, Olivier Biton, Todd J. Green, Val Tannen, Zachary G. Ives
Issue Date:June 2007
pp. 1131-1133
Mashup Feeds is a system that supports integrated web service feeds as continuous queries. We introduce collection-based stream processing semantics to enable information extraction by monitoring source evolution over time.
     
Expression Transfer between Photographs through Multilinear AAM's
Found in: Graphics, Patterns and Images, SIBGRAPI Conference on
By Ives Macedo, Emilio Vital Brazil, Luiz Velho
Issue Date:October 2006
pp. 239-246
Expression Transfer is a method for mapping a photographed expression performed by a given subject onto the photograph of another person?s face. Building on well succeeded previous works by the vision researchers (facial expression decomposition, active ap...
 
Reconciling while tolerating disagreement in collaborative data sharing
Found in: Proceedings of the 2006 ACM SIGMOD international conference on Management of data (SIGMOD '06)
By Nicholas E. Taylor, Zachary G. Ives
Issue Date:June 2006
pp. 13-24
In many data sharing settings, such as within the biological and biomedical communities, global data consistency is not always attainable: different sites' data may be dirty, uncertain, or even controversial. Collaborators are willing to share their data, ...
     
Distance Functions Association for Content-Based Image Retrieval using Multiple Comparison Criteria
Found in: Computer-Based Medical Systems, IEEE Symposium on
By Ives R. V. Pola, Agma J. M. Traina, Caetano Traina Jr.
Issue Date:June 2006
pp. 899-904
The comparison operators available in traditional Database Management Systems (DBMS) are not adequate to handle complex data such as images, rather comparing them using similarity operators is the option of choice. Similarity operators need a way to measur...
 
Quantifying eavesdropping vulnerability in sensor networks
Found in: Proceedings of the 2nd international workshop on Data management for sensor networks (DMSN '05)
By Insup Lee, Madhukar Anand, Zachary Ives
Issue Date:August 2005
pp. 3-9
With respect to security, sensor networks have a number of considerations that separate them from traditional distributed systems. First, sensor devices are typically vulnerable to physical compromise. Second, they have significant power and processing con...
     
The Piazza Peer Data Management System
Found in: IEEE Transactions on Knowledge and Data Engineering
By Alon Y. Halevy, Zachary G. Ives, Jayant Madhavan, Peter Mork, Dan Suciu, Igor Tatarinov
Issue Date:July 2004
pp. 787-798
<p><b>Abstract</b>—Intuitively, data management and data integration tools should be well-suited for exchanging information in a semantically meaningful way. Unfortunately, they suffer from two significant problems: They typically require...
 
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