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Physical Sciences and Mathematics Commons™
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- Keyword
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- Computer Vision (2)
- Digital elevation models (2)
- Machine Learning (2)
- Photogrammetry (2)
- Applications (1)
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- Autonomous error estimation (1)
- Caching (1)
- Compressed sensing (1)
- Content distribution (1)
- Diversity (1)
- Handoff (1)
- Horizontal decorrelation length (1)
- Measurement error theory (1)
- Measurement study (1)
- Non-commutative harmonic analysis (1)
- Peer-to-peer (1)
- Symmetry group (1)
- Vehicular networks (1)
- WiFi (1)
Articles 1 - 9 of 9
Full-Text Articles in Physical Sciences and Mathematics
Autonomous Geometric Precision Error Estimation In Low-Level Computer Vision Tasks, Andrés Corrada-Emmanuel, Howard Schultz
Autonomous Geometric Precision Error Estimation In Low-Level Computer Vision Tasks, Andrés Corrada-Emmanuel, Howard Schultz
Computer Science Department Faculty Publication Series
Errors in map-making tasks using computer vision are sparse. We demonstrate this by considering the construction of digital elevation models that employ stereo matching algorithms to triangulate real-world points. This sparsity, coupled with a geometric theory of errors recently developed by the authors, allows for autonomous agents to calculate their own precision independently of ground truth. We connect these developments with recent advances in the mathematics of sparse signal reconstruction or compressed sensing. The theory presented here extends the autonomy of 3-D model reconstructions discovered in the 1990s to their errors.
Autonomous Estimates Of Horizontal Decorrelation Lengths For Digital Elevation Models, Andres Corrada-Emmanuel, Howard Schultz
Autonomous Estimates Of Horizontal Decorrelation Lengths For Digital Elevation Models, Andres Corrada-Emmanuel, Howard Schultz
Computer Science Department Faculty Publication Series
The precision errors in a collection of digital elevation models (DEMs) can be estimated in the presence of large but sparse correlations even when no ground truth is known. We demonstrate this by considering the problem of how to estimate the horizontal decorrelation length of DEMs produced by an automatic photogrammetric process that relies on the epipolar constraint equations. The procedure is based on a set of autonomous elevation difference equations recently proposed by us. In this paper we show that these equations can only estimate the precision errors of DEMs. The accuracy errors are unknowable since there is no …
Value Function Approximation In Reinforcement Learning Using The Fourier Basis, George Konidaris, Sarah Osentoski
Value Function Approximation In Reinforcement Learning Using The Fourier Basis, George Konidaris, Sarah Osentoski
Computer Science Department Faculty Publication Series
We describe the Fourier Basis, a linear value function approximation scheme based on the Fourier Series. We empirically evaluate its properties, and demonstrate that it performs well compared to Radial Basis Functions and the Polynomial Basis, the two most popular fixed bases for linear value function approximation, and is competitive with learned Proto-Value Functions even though no extra experience or computation is required.
Here Or There: Preference Judgments For Relevance, Ben Carterette, Paul N. Bennett, David Maxwell Chickering, Susan T. Dumais
Here Or There: Preference Judgments For Relevance, Ben Carterette, Paul N. Bennett, David Maxwell Chickering, Susan T. Dumais
Computer Science Department Faculty Publication Series
Information retrieval systems have traditionally been evaluated over absolute judgments of relevance: each document is judged for relevance on its own, independent of other documents that may be on topic. We hypothesize that preference judgments of the form “document A is more relevant than document B” are easier for assessors to make than absolute judgments, and provide evidence for our hypothesis through a study with assessors. We then investigate methods to evaluate search engines using preference judgments. Furthermore, we show that by using inferences and clever selection of pairs to judge, we need not compare all pairs of documents in …
Watch Global, Cache Local: Youtube Network Traffic At A Campus Network - Measurements And Implications, Michael Zink, Kyoungwon Suh, Yu Gu, Jim Kurose
Watch Global, Cache Local: Youtube Network Traffic At A Campus Network - Measurements And Implications, Michael Zink, Kyoungwon Suh, Yu Gu, Jim Kurose
Computer Science Department Faculty Publication Series
User Generated Content has become very popular since the birth of web services such as YouTube allowing the distribution of such user-produced media content in an easy manner. YouTube-like services are different from existing traditional VoD services because the service provider has only limited control over the creation of new content. We analyze how the content distribution in YouTube is realized and then conduct a measurement study of YouTube traffic in a large university campus network. The analysis of the traffic shows that: (1) No strong correlation is observed between global and local popularity; (2) neither time scale nor user …
Manifold Alignment Using Procrustes Analysis, Chang Wang, Sridhar Mahadevan
Manifold Alignment Using Procrustes Analysis, Chang Wang, Sridhar Mahadevan
Computer Science Department Faculty Publication Series
In this paper we introduce a novel approach to manifold alignment, based on Procrustes analysis. Our approach di®ers from \semi- supervised alignment" in that it results in a mapping that is de¯ned everywhere { when used with a suitable dimensionality reduction method { rather than just on the training data points. We describe and evaluate our approach both theoretically and experimen- tally, providing results showing useful knowl- edge transfer from one domain to another. Novel applications of our method including cross-lingual information retrieval and trans- fer learning in Markov decision processes are presented.
Pacemakers And Implantable Cardiac Defibrillators: Software Radio Attacks And Zero-Power Defenses, Daniel Halperin
Pacemakers And Implantable Cardiac Defibrillators: Software Radio Attacks And Zero-Power Defenses, Daniel Halperin
Computer Science Department Faculty Publication Series
Our study analyzes the security and privacy properties of an implantable cardioverter defibrillator (ICD). Introduced to the U.S. market in 2003, this model of ICD includes pacemaker technology and is designed to communicate wirelessly with a nearby external programmer in the 175 kHz frequency range. After partially reverse-engineering the ICD’s communications protocol with an oscilloscope and a software radio, we implemented several software radio-based attacks that could compromise patient safety and patient privacy. Motivated by our desire to improve patient safety, and mindful of conventional trade-offs between security and power consumption for resourceconstrained devices, we introduce three new zero-power defenses …
Resisting Structural Reidentification Anonymized Social Networks, Michael Hay, Gerome Miklau, David Jensen, Don Towsley, Philipp Weis
Resisting Structural Reidentification Anonymized Social Networks, Michael Hay, Gerome Miklau, David Jensen, Don Towsley, Philipp Weis
Computer Science Department Faculty Publication Series
We identify privacy risks associated with releasing network data sets and provide an algorithm that mitigates those risks. A network consists of entities connected by links representing relations such as friendship, communication, or shared activity. Maintaining privacy when publishing networked data is uniquely challenging because an individual’s network context can be used to identify them even if other identifying information is removed. In this paper, we quantify the privacy risks associated with three classes of attacks on the privacy of individuals in networks, based on the knowledge used by the adversary. We show that the risks of these attacks vary …
Interactive Wifi Connectivity For Moving Vehicles, Aruna Balasubramanian, Ratul Mahajan, Arun Venkataramani, Brian Neil Levine, John Zahorjan
Interactive Wifi Connectivity For Moving Vehicles, Aruna Balasubramanian, Ratul Mahajan, Arun Venkataramani, Brian Neil Levine, John Zahorjan
Computer Science Department Faculty Publication Series
We ask if the ubiquity of WiFi can be leveraged to provide cheap connectivity from moving vehicles for common applications such as Web browsing and VoIP. Driven by this question, we conduct a study of connection quality available to vehicular WiFi clients based on measurements from testbeds in two different cities. We find that current WiFi handoff methods, in which clients communicate with one basestation at a time, lead to frequent disruptions in connectivity. We also find that clients can overcome many disruptions by communicating with multiple basestations simultaneously. These findings lead us to develop ViFi, a protocol that opportunistically …