Computer Sciences Commons^™

Tr-2013016: Supporting Genp With Random Multipliers, Victor Y. Pan, Guoliang Qian, Xiaodong Yan

Computer Science Technical Reports

No abstract provided.

Tr-2013009: Algebraic Algorithms, Ioannis Z. Emiris, Victor Y. Pan, Elias P. Tsigaridas

Computer Science Technical Reports

No abstract provided.

Mexsvms: Mid-Level Features For Scalable Action Recognition, Du Tran, Lorenzo Torresani

Computer Science Technical Reports

This paper introduces MEXSVMs, a mid-level representation enabling efficient recognition of actions in videos. The entries in our descriptor are the outputs of several movement classifiers evaluated over spatial-temporal volumes of the image sequence, using space-time interest points as low-level features. Each movement classifier is a simple exemplar-SVM, i.e., an SVM trained using a single positive video and a large number of negative sequences. Our representation offers two main advantages. First, since our mid-level features are learned from individual video exemplars, they require minimal amount of supervision. Second, we show that even simple linear classification models trained on our global …

Privacy-Preserving Screen Capture: Closing The Loop For Medical Informatics Usability, Joseph Cooley, Sean Smith

Computer Science Technical Reports

As information technology permeates healthcare (particularly provider-facing systems), maximizing system effectiveness requires the ability to document and analyze tricky or troublesome usage scenarios. However, real-world medical applications are typically replete with privacy-sensitive data regarding patients, diagnoses, clinicians, and EMR user interface details; any instrumentation for screen capture (capturing and recording the scenario depicted on the screen) needs to respect these privacy constraints. Furthermore, real-world medical informatics systems are typically composed of modules from many sources, mission-critical and often closed-source; any instrumentation for screen capture cannot rely on access to structured output or software internals. In this paper, we present a …

Meshgit: Diffing And Merging Polygonal Meshes, Jonathan D. Denning, Fabio Pellacini

Computer Science Technical Reports

This paper presents MeshGit, a practical algorithm for diffing and merging polygonal meshes. Inspired by version control for text editing, we introduce the mesh edit distance as a measure of the dissimilarity between meshes. This distance is defined as the minimum cost of matching the vertices and faces of one mesh to those of another. We propose an iterative greedy algorithm to approximate the mesh edit distance, which scales well with model complexity, providing a practical solution to our problem. We translate the mesh correspondence into a set of mesh editing operations that transforms the first mesh into the second. …

Toward Evaluating Progressive Rendering Methods In Appearance Design Tasks, Jiawei Ou, Ondrej Karlik, Jaroslav Krivanek, Fabio Pellacini

Computer Science Technical Reports

Progressive rendering is becoming a popular alternative to precomputation approaches for appearance design tasks. Images created by different progressive algorithms exhibit various kinds of visual artifacts at the early stages of computation. We present a user study that investigates the effects of these artifacts on user performance in appearance design tasks. Specifically, we ask both novice and expert subjects to perform lighting and material editing tasks with the following algorithms: random path tracing, quasi-random path tracing, progressive photon mapping, and virtual point light (VPL) rendering. Data collected from the experiments suggest that path tracing is strongly preferred to progressive photon …

Access Control Realities As Observed In A Clinical Medical Setting, Sara Sinclair, Sean Smith

Computer Science Technical Reports

Effective computer security requires looking not just at technology, but also at how it meshes with users in the real-world enterprises depending on it. As part of a longer-term series of projects, we have been looking at these issues-- particularly access control-- in a variety of real-world enterprises. In previous work, we looked at companies in the finance and software industries; this paper reports on a study of a hospital's access control systems. Both studies employ ethnographic methods to elicit observations on the failures of current access control technologies in large, dynamic organizations; participants in the corporate study were largely …

Access Control Hygiene And The Empathy Gap In Medical It, Yifei Wang, Sean Smith, Andrew Gettinger

Computer Science Technical Reports

In theory, access control is a solved problem. In practice, large real-world enterprises still report trouble: de facto policy becomes unmanageable; users circumvent controls. These issues can be particularly critical in medical IT, such as emerging EMR and EHR, where access control errors can have serious repercussions. In this paper, we investigate how real-world EMR users think about access control when they are making policy decisions in the abstract---and when they are actually using the system in treatment scenarios. Mismatches suggest places ("empathy gaps") where new policy tools may be needed.

Wallpaper Maps, M. Douglas Mcilroy

Computer Science Technical Reports

A wallpaper map is a conformal projection of a spherical earth onto regular polygons with which the plane can be tiled continuously. A complete set of distinct wallpaper maps that satisfy certain natural symmetry conditions is derived and illustrated. Though all of the projections have been published before, the family had not been characterized as a whole. Some wallpaper maps generalize to one-parameter subfamilies in which the sphere is pre-transformed by a conformal automorphism.

Tr-2012004: Solving Linear Systems Of Equations With Randomization, Augmentation And Aggregation, Victor Y. Pan, Guoliang Qian

Computer Science Technical Reports

No abstract provided.

Tr-2012011: Binding Modalities, Sergei N. Artemov, Tatiana Yavorskaya (Sidon)

Computer Science Technical Reports

No abstract provided.

Tr-2012005: Randomized Matrix Computations, Victor Y. Pan, Guoliang Qian, Ai-Long Zheng

Computer Science Technical Reports

No abstract provided.

Tr-2012015: Randomized Matrix Methods For Real And Complex Polynomial Root-Finding, Victor Y. Pan, Guoliang Qian, Ai-Long Zheng

Computer Science Technical Reports

No abstract provided.

Tr-2012010: Explicit Generic Common Knowledge, Evangelia Antonakos

Computer Science Technical Reports

No abstract provided.

Tr-2012001: Algebraic Algorithms, Ioannis Z. Emiris, Victor Y. Pan, Elias P. Tsigaridas

Computer Science Technical Reports

No abstract provided.

Tr-2012002: Randomized Matrix Methods For Real And Complex Polynomial Root-Finding, Victor Y. Pan, Guoliang Qian, Ai-Long Zheng

Computer Science Technical Reports

No abstract provided.

Tr-2012003: Root-Finding And Root-Refining For A Polynomial Equation, Victor Y. Pan

Computer Science Technical Reports

No abstract provided.

Tr-2012006: Randomized Matrix Computations Ii, Victor Y. Pan, Guoliang Qian, Ai-Long Zheng

Computer Science Technical Reports

No abstract provided.

Tr-2012008: Randomized Matrix Computations Iii, Victor Y. Pan, Guoliang Qian, Ai-Long Zheng

Computer Science Technical Reports

No abstract provided.

Tr-2012009: Randomized Matrix Computations Iv, Victor Y. Pan, Guoliang Qian, Ai-Long Zheng

Computer Science Technical Reports

No abstract provided.

Tr-2012012: Condition Estimation By Means Of Power Method, Victor Y. Pan

Computer Science Technical Reports

No abstract provided.

Tr-2012016: More On The Power Of Randomized Matrix Multiplication I, Victor Y. Pan, Guoliang Qian

Computer Science Technical Reports

No abstract provided.

Tr-2012007: Solving Linear Systems Of Equations With Randomization, Augmentation And Aggregation Ii, Victor Y. Pan, Guoliang Qian

Computer Science Technical Reports

No abstract provided.

Tr-2012013: Condition Numbers Of Random Toeplitz And Circulant Matrices, Victor Y. Pan, Guoliang Qian

Computer Science Technical Reports

No abstract provided.

Tr-2012014: More On The Power Of Randomized Matrix Multiplication, Victor Y. Pan, Guoliang Qian

Computer Science Technical Reports

No abstract provided.

Security Applications Of Formal Language Theory, Len Sassaman, Meredith L. Patterson, Sergey Bratus, Michael E. Locasto, Anna Shubina

Computer Science Technical Reports

We present an approach to improving the security of complex, composed systems based on formal language theory, and show how this approach leads to advances in input validation, security modeling, attack surface reduction, and ultimately, software design and programming methodology. We cite examples based on real-world security flaws in common protocols representing different classes of protocol complexity. We also introduce a formalization of an exploit development technique, the parse tree differential attack, made possible by our conception of the role of formal grammars in security. These insights make possible future advances in software auditing techniques applicable to static and dynamic …

A 3-D Lighting And Shadow Analysis Of The Jfk Zapruder Film (Frame 317), Hany Farid

Computer Science Technical Reports

Claims of a broader conspiracy behind U.S. President John F. Kennedy's assassination have persisted for the past nearly five decades. The Zapruder film is considered to be the most complete recording of JFK's assassination. Many have claimed that this 8mm film was manipulated to conceal evidence of a second shooter, which would invalidate the claim that a lone gunman, Lee Harvey Oswald, was responsible for JFK's assassination. Here we consider the viability of one specific claim of postproduction tampering in the Zapruder film.

Hide-N-Sense: Privacy-Aware Secure Mhealth Sensing, Shrirang Mare, Jacob Sorber, Minho Shin, Cory Cornelius, David Kotz

Computer Science Technical Reports

As healthcare in many countries faces an aging population and rising costs, mobile sensing technologies promise a new opportunity. Using mobile health (mHealth) sensing, which uses medical sensors to collect data about the patients, and mobile phones to act as a gateway between sensors and electronic health record systems, caregivers can continuously monitor the patients and deliver better care. Furthermore, individuals can become better engaged in monitoring and managing their own health. Although some work on mHealth sensing has addressed security, achieving strong privacy for low-power sensors remains a challenge.

We make three contributions. First, we propose an mHealth sensing …

Bgrep And Bdiff: Unix Tools For High-Level Languages, Gabriel A. Weaver, Sean W. Smith

Computer Science Technical Reports

The rise in high-level languages for system administrators requires us to rethink traditional UNIX tools designed for these older data formats. We propose new block-oriented tools, bgrep and bdiff, operating on syntactic blocks of code rather than the line, the traditional information container of UNIX. Transcending the line number allows us to introduce longitudinal diff, a mode of bdiff that lets us track changes across arbitrary blocks of code. We present a detailed implementation roadmap and evaluation framework for the full version of this paper. In addition we demonstrate how the design of our tools already addresses several real-wold problems …

Beyond Selinux: The Case For Behavior-Based Policy And Trust Languages, Sergey Bratus, Michael E. Locasto, Boris Otto, Rebecca Shapiro, Sean W. Smith, Gabriel Weaver

Computer Science Technical Reports

Despite the availability of powerful mechanisms for security policy and access control, real-world information security practitioners---both developers and security officers---still find themselves in need of something more. We believe that this is the case because available policy languages do not provide clear and intelligible ways to allow developers to communicate their knowledge and expectations of trustworthy behaviors and actual application requirements to IT administrators. We work to address this policy engineering gap by shifting the focus of policy language design to this communication via behavior-based policies and their motivating scenarios.