Totally non-symplectic Anosov actions on tori and nilmanifolds (2009)
Fisher, David, Kalinin, Boris, Spatzier, Ralf
We show that sufficiently irreducible totally non-symplectic Anosov actions of higher rank abelian groups on tori and nilmanifolds are $\ci$-conjugate to affine actions.
Archana Chidan, Rebecca Devasher, Patrick Ferro, David Fisher, Sudipa Kirtley, Larry Merkle, ...
Abstract – Our project focuses on evaluating the impact of pen-based computing devices and collaboration-facilitating software in the engineering, science, and technical communication classrooms....
Abstract Static Analysis for Syntax Objects (2008)
We describe an s-expression based syntax-extension framework much like Scheme macros, with a key additional facility: the ability to define static semantics, such as type systems or program analysis,...
Groups acting on manifolds: around the Zimmer program (2008)
This paper is a survey on the {\em Zimmer program}. In it's broadest form, this program seeks an understanding of actions of large groups on compact manifolds. The goals of this survey are $(1)$ to...
Nonergodic actions, cocycles and superrigidity (2008)
David Fisher, Dave Witte Morris, Kevin Whyte
Abstract. This paper proves various results concerning nonergodic actions of locally compact groups and particularly Borel cocycles defined over such actions. The general philosophy is to reduce the...
An Analysis of Engagement Algorithms for Real-Time Weapons Effects (2008)
John Mann, David Fisher, Matt Kraus, Erik Lowndes
Performance and fidelity requirements are the main drivers when selecting algorithms for real-time weapons effects. In many cases, look-up tables are the method of choice for real-time applications....
Out (Fn) and the Spectral Gap Conjecture (2008)
For n>2, given ϕ1,...,ϕn randomly chosen isometries of S2, it is well known that the group Γ generated by ϕ1,...,ϕn acts ergodically on S2. In 1999, Gamburd, Jakobson, and Sarnak conjectured...
To appear in J. Functional Programming 1 Multi-return Function Call (2008)
It is possible to extend the basic notion of “function call ” to allow functions to have multiple return points. This turns out to be a surprisingly useful mechanism. This article conducts a...
David Falconer, David Shani, Moshe Ran, Vacit Arat, Demos Kostas, ...
SR-Telecom Re: This contribution is submitted in response to “Call for Contributions: Session #12 ” by 802.16.3
Archana Chidan, Rebecca Devasher, Patrick Ferro, David Fisher, Sudipa Mitra-kirtley, Larry Merkle, ...
Abstract – Our project focuses on evaluating the impact of pen-based computing devices and collaboration-facilitating software in the engineering, science, and technical communication classrooms....
on origami with a pop-up thesis in the first place and who has been very patient during this year. Thanks also to "Fred " (who I now know really exists) for a never-ending supply of...
CRYSTAL Inducing a Conceptual Dictionary * (2008)
Stephen Soderl, David Fisher, Jonathan Aseltine, Wendy Lehnert
One of the central knowledge sources of an information extraction (IE) system IS a dictionary of linguistic patterns that can be used to identify references to relevant information in a text...
Groups not acting on manifolds (2008)
Fisher, David, Silberman, Lior
In this article we collect a series of observations that constrain actions of many groups on compact manifolds. In particular, we show that "generic" finitely generated groups have no smooth volume...
Groups Not Acting on Manifolds (2008)
Fisher, David, Silberman, Lior
In this article, we collect a series of observations that constrain actions of many groups on compact manifolds. In particular, we show that “generic” finitely generated groups have no smooth...
Ta Pp Ed, Stephen Soderl, David Aronow, David Fisher, Jonathan Aseltine, Wendy Lehnert
This paper describes the BADGER text analysis system, which identifies concepts contained in a text based on linguistic context. A key component of BADGER is the CRYSTAL dictionary induction system...
Machine Learning of Text Analysis Rules for Clinical Records (2007)
Stephen Soderl, David Aronow, David Fisher, Jonathan Aseltine, Wendy Lehnert
Automatically extracting information in clinical free text can make available an information resource that is largely untapped. This paper describes the BADGER text analysis system, which identifies...
Coarse differentiation of quasi-isometries II: Rigidity for Sol and Lamplighter groups (2007)
Eskin, Alex, Fisher, David, Whyte, Kevin
In this paper, which is the continuation of [EFW2], we complete the proof of the quasi-isometric rigidity of Sol and the lamplighter groups. The results were announced in [EFW1].
Alex Eskin, David Fisher, Kevin Whyte
differentiation of quasi-isometries I: spaces
Strengthening Kazhdan's Property $(T)$ by Bochner Methods (2006)
Fisher, David, Hitchman, Theron
In this paper, we propose a property which is a natural generalization of Kazhdan's property $(T)$ and prove that many, but not all, groups with property $(T)$ also have this property. Let $\G$ be a...
Coarse differentiation of quasi-isometries I: spaces not quasi-isometric to Cayley graphs (2006)
Eskin, Alex, Fisher, David, Whyte, Kevin
In this paper, we prove that certain spaces are not quasi-isometric to Cayley graphs of finitely generated groups. In particular, we answer a question of Woess and prove a conjecture of Diestel and...
$\Out(F_n)$ and the spectral gap conjecture (2006)
For $n>2$, given $\phi_1,...,\phi_n$ randomly chosen isometries of $S^2$, it is well-known that the group $\G$ generated by $\phi_1,...,\phi_n$ acts ergodically on $S^2$. It is conjectured in...
WEATHER ASPECTS OF THE SONIC BOOM (2006)
An explanation of the effect of meteorological conditions on the path of the sonic boom is presented. Areas covered by sonic booms resulting from aircraft flying at various Mach numbers and dive...
Allan, James, Connell, Margaret E., Croft, W. B., Feng, Fang-Fang, Fisher, David, Li, Xiaoyan
This year the Center for Intelligent Information Retrieval (CIIR) at the University of Massachusetts participated in three of the tracks: the cross-language, question answering, and query tracks. We...
University of Massachusetts: MUC-3 Test Results and Analysis (2006)
Lehnert, Wendy, Cardie, Claire, Fisher, David, Riloff, Ellen, Williams, Robert
We believe that the score reports we obtained for TST2 provide an accurate assessment of our system's capabilities insofar as they are consistent with the results of our own internal tests conducted...
Fisher, David, Baird, Janis, Payne, Liz, Lucas, Patricia, Kleijnen, Jos, Roberts, Helen, ...
Background: Slower rates of infant growth are associated with increased rates of death from ischaemic heart disease (IHD) in later life. We carried out a systematic review to assess the association...
Fisher, David, Baird, Janis, Payne, Liz, Lucas, Patricia, Kleijnen, Jos, Roberts, Helen, ...
BACKGROUND: Slower rates of infant growth are associated with increased rates of death from ischaemic heart disease (IHD) in later life. We carried out a systematic review to assess the association...
Static analysis for syntax objects (2006)
We describe an s-expression based syntax-extension framework much like Scheme macros, with a key additional facility: the ability to define static semantics, such as type systems or program analysis,...
Fisher, David, Baird, Janis, Payne, Liz, Lucas, Patricia, Kleijnen, Jos, Roberts, Helen, ...
Background Slower rates of infant growth are associated with increased rates of death from ischaemic heart disease (IHD) in later life. We carried out a systematic review to assess the association...
Out(Fn) and the spectral gap conjecture (2006)
For n > 2, given ϕ1,…,ϕn randomly chosen isometries of S2, it is well known that the group Γ generated by ϕ1,…,ϕn acts ergodically on S2. In 1999, Gamburd, Jakobson, and...
Cocycle superrigidity and harmonic maps with infinite-dimensional targets (2006)
Fisher, David, Hitchman, Theron
We announce a generalization of Zimmer's cocycle superrigidity theorem proven using harmonic map techniques. This allows us to generalize many results concerning higher-rank lattices to all lattices...
Fisher, David, Baird, Janis, Payne, Liz, Lucas, Patricia, Kleijnen, Jos, Roberts, Helen, ...
Background Slower rates of infant growth are associated with increased rates of death from ischaemic heart disease (IHD) in later life. We carried out a systematic review to assess the association...
Cocycle superrigidity and harmonic maps with infinite dimensional targets (2005)
Fisher, David, Hitchman, Theron
We announce a generalization of Zimmer's cocycle superrigidity theorem proven using harmonic map techniques. This allows us to generalize many results concerning higher rank lattices to all lattices...
Quasi-isometries and rigidity of solvable groups (2005)
Eskin, Alex, Fisher, David, Whyte, Kevin
In this note, we announce the first results on quasi-isometric rigidity of non-nilpotent polycyclic groups. In particular, we prove that any group quasi-isometric to the three dimenionsional solvable...
Local Rigidity of group actions: Past, Present, Future (2005)
This survey aims to cover the motivation for and history of the study of local rigidity of group actions. There is a particularly detailed discussion of recent results, including outlines of some...
First cohomology and local rigidity of group actions (2005)
Given a topological group $G$, and a finitely generated group $\G$, a homomorphism $\pi:\G{\to}G$ is {\em locally rigid} if any nearby by homomorphism $\pi'$ is conjugate to $\pi$ by a small element...
Noneistence of Invariant Rigid Structures and Invariant Almost Rigid Structures (2005)
Benveniste, E. Jerome, Fisher, David
We prove that certain volume preserving actions of Lie groups and their lattices do not preserve rigid geometric structures in the sense of Gromov. The actions considered are the "exotic" examples...
Being big or growing fast: systematic review of size and growth in infancy and later obesity (2005)
Baird, Janis, Fisher, David, Lucas, Patricia, Kleijnen, Jos, Roberts, Helen, Law, Catherine
Objectives: To assess the association between infant size or growth and subsequent obesity and to determine if any association has been stable over time. Design: Systematic review. Data sources:...
Quasi-isometries and rigidity of solvable groups (2005)
Alex Eskin, David Fisher, Kevin Whyte
Abstract. In this note, we announce the first results on quasi-isometric rigidity of non-nilpotent polycyclic groups. In particular, we prove that any group quasiisometric to the three dimenionsional...
David Carney, David Fisher, Patrick Place
Use of any trademarks in this report is not intended in any way to infringe on the rights of the trademark holder. Internal use. Permission to reproduce this document and to prepare derivative works...
Il mago della guerra, David Fischer. . - Milano, Longanesi, 2005.
First cohomology, rigidity and deformations of isometric group actions (2004)
In 1964, Weil gave a criterion for local rigidity of a homomorphism from a finitely generated group $\G$ to a finite dimensional Lie group $G$ in terms of cohomology of $\G$ with coefficients in the...
Local rigidity of affine actions of higher rank groups and lattices (2004)
Fisher, David, Margulis, Gregory
Let $J$ be a semisimple Lie group with all simple factors of real rank at least two. Let $\Gamma
Deformations of group actions (2004)
Let $G$ be a noncompact real algebraic group and $\G
Continuous quotients for lattice actions on compact manifolds (2004)
Let G be a subgroup of finite index in SL(n,Z) for N > 4. Suppose G acts continuously on a manifold M, with fundamental group Z^n, preserving a measure that is positive on open sets. Further assume...
Nonexistence of invariant rigid structures and invariant almost rigid structures (2004)
Benveniste, E. Jerome, Fisher, David
We prove that certain volume preserving actions of Lie groups and their lattices do not preserve rigid geometric structures in the sense of Gromov. The actions considered are the "exotic" examples...
Lisa L. Brownsword, David J. Carney, David Fisher, Grace Lewis, Craig Meyers, Edwin J. Morris, ...
Integration of Software-Intensive Systems Initiative Unlimited distribution subject to the copyright. This report was prepared for the
Almost isometric actions, property $(T)$, and local rigidity (2003)
Fisher, David, Margulis, G. A.
Let $\Gamma$ be a discrete group with property $(T)$ of Kazhdan. We prove that any Riemannian isometric action of $\Gamma$ on a compact manifold $X$ is locally rigid. We also prove a more general...
Local Rigidity for Cocycles (2003)
Fisher, David, Margulis, G. A.
In this paper we study perturbations of constant cocycles for actions of higher rank semi-simple algebraic groups and their lattices. Roughly speaking, for ergodic actions, Zimmer's cocycle...
When is a group action determined by its orbit structure? (2003)
We present a simple approach to questions of topological orbit equivalence for actions of countable groups on topological and smooth manifolds. For example, for any action of a countable group...
One-to-One Modeling and Simulation of Unbounded Systems: Experiences and Lessons (2002)
E. Yücesan, David Fisher, J. L. Snowdon, J. M. Charnes, Rohyt V. Belani, ...
Conventional computer modeling and simulation have focused on computer objects that represent elements of the real world. In this paper we present a new approach to modeling and simulation in which...
The socio-economic consequences of tourism in Levuka, Fiji (2000)
This thesis examines the proposition that the local population at a tourist destination copy the economic behaviour of tourists and learn to give economic value to the same objects and activities...
On the arithmetic structure of lattice actions on compact manifolds / (1999)
Thesis (Ph. D.)--University of Chicago, Dept. of Mathematics, June 1999.
In an earlier section of this report, it was noted that as an approximation the shadow area produced by the finite hemispherical source had been excluded in the derivation of the equation for the...
Current Perspectives on Interoperability (1998)
Brownsword, Lisa L., Carney, David J., Fisher, David, Lewis, Grace, Meyers, Craig
This report describes current research within the software engineering community on the topic of interoperability between software systems. That research includes analyses of the different types of...
Topics in Interoperability: System-of-Systems Evolution (1998)
Carney, David, Fisher, David, Place, Patrick
This report examines how interoperable systems of systems evolve. It first considers several ways in which interoperability can be defined and then examines the notion of software evolution itself....
Some Current Approaches to Interoperability (1998)
Carney, David, Fisher, David, Morris, Ed, Place, Pat
This technical note examines some of the complexities of interoperability and some recent research approaches to achieving it. There are many reasons why achieving interoperability between complex,...
System-of-Systems Navigator: An Approach for Managing System-of-Systems Interoperability (1998)
Brownsword, Lisa, Fisher, David, Morris, Ed, Smith, James, Kirwan, Patrick
We have crossed a threshold where most of our large software systems can no longer be constructed as monoliths specified by a single, focused, and unified team; implemented as a unit; and tested to...
Van Dokkum, Pieter G., Franx, Marijn, Kelson, Daniel D., Illingworth, Garth D., Fisher, David, Fabricant, Daniel
We use a large mosaic of HST WFPC2 images to measure the colors and morphologies of 194 spectroscopically confirmed members of the rich galaxy cluster CL1358+62 at z=0.33. We study the...
Barry Glasgow And, Barry Glasgow, Alan M, Dan Binney, Lila Ghemri, David Fisher
MetLife processes over 300,000 life insurance applications a year. Underwriting of these applications is labor intensive. Automation is difficult since they include many free-form text fields. MITA,...
The Domination and Competition Graphs of a Tournament (1998)
David Fisher, J. Richard Lundgren, Sarah K. Merz, K. Brooks Reid
. Vertices x and y dominate a tournament T if for all vertices z<F NaN> 6= x; y; either x beats z or y beats z. Let dom(T ) be the graph on the vertices of T with edges between pairs of...
Barry Glasgow, Alan Mandell, Alan M, Dan Binney, Lila Ghemri, David Fisher
MetLife processes over 300,000 life insurance applications a year. Underwriting of these applications is labor intensive. Automation is difficult since they include many free-form text fields. MITA,...
Report to the President's Commission on Critical Infrastructure Protection. (1997)
Ellis, James, Fisher, David, Longstaff, Thomas, Pesante, Linda, Pethia, Richard
This report was written for the President's Commission on Critical Infrastructure Protection. Based on the experience of the CERTSM Coordination Center, we identify threats to and vulnerabilities of...
James Ellis, David Fisher, Thomas Longstaff, Linda Pesante, Richard Pethia, James Ellis, ...
The ideas and findings in this report should not be construed as an official DoD position. It is published in the interest of scientific and technical information exchange.
Automatically Learned vs. Hand-crafted Text Analysis Rules (1997)
Stephen Soderland, David Fisher, Wendy Lehnert
As vast quantities of on-line text become available, there is an increasing need for systems that automatically analyze the conceptual content of natural language text. Systems that operate on...
The Number of Dependent Arcs in an Acyclic Orientation (1997)
David Fisher, Kathryn Fraughnaugh, Larry Langley
d max (G) = e(G) \Gamma n(G) + 1. For a connected graph G, an acyclic orientation with e(G) \Gamma n(G) + 1 dependent arcs can be obtained by orienting edges away from the root of a depth-first...
Automatically Learned vs. Hand-crafted Text Analysis Rules (1997)
Stephen Soderland, David Fisher, Wendy Lehnert
As vast quantities of on-line text become available, there is an increasing need for systems that automatically analyze the conceptual content of natural language text. Systems that operate on...
Bayesian Target Tracking After Group Pattern Distortion (1997)
Neil Gordon, David Salmond, David Fisher
A standard assumption of most multiple target tracking filters is that all the targets move independently of one other. However, in many cases, it is known a-priori that the targets move (at least...
Report to the President's Commission on Critical Infrastructure Protection (1997)
James Ellis, James Ellis, David Fisher, David Fisher, Thomas Longstaff, Thomas Longstaff, ...
: This report was submitted to the President's Commission on Critical Infrastructure Protection for their consideration. Based on the experience of the CERT SM Coordination Center, we identify...
James Ellis, David Fisher, Thomas Longstaff, Linda Pesante, Richard Pethia, James Ellis, ...
The ideas and findings in this report should not be construed as an official DoD position. It is published in the interest of scientific and technical information exchange.
A Search for Counter-Rotating Stars in S0 Galaxies (1996)
Kuijken, Konrad, Fisher, David, Merrifield, Michael R.
We have obtained high signal-to-noise spectra along the major axes of 28 S0 galaxies in order to search for the presence of disk stars on retrograde orbits. Full line-of-sight velocity distributions...
Our lives are full of self-deception: for example, every generation lays claim to an increased pace of life. Every generation likes to think it has invented sex and management. We constantly kid...
CRYSTAL: Inducing a Conceptual Dictionary (1995)
Soderland, Stephen, Fisher, David, Aseltine, Jonathan, Lehnert, Wendy
One of the central knowledge sources of an information extraction system is a dictionary of linguistic patterns that can be used to identify the conceptual content of a text. This paper describes...
Description of the UMass system as used for MUC-6 (1995)
David Fisher, Stephen Soderl, Joseph Mccarthy, Fangfang Feng, Wendy Lehnert
Issues in Inductive Learning of Domain-Specific Text Extraction Rules (1995)
Stephen Soderland, David Fisher, Jonathan Aseltine, Wendy Lehnert
Domain-speci#c text analysis requires a dictionary of linguistic patterns that identify references to relevant information in a text. This paper describes CRYSTAL, a fully automated tool that induces...
CRYSTAL: Inducing a Conceptual Dictionary (1995)
Stephen Soderland, David Fisher, Jonathan Aseltine, Wendy Lehnert
One of the central knowledge sources of an information extraction (IE) system is a dictionary of linguistic patterns that can be used to identify references to relevant information in a text....
Machine Learning of Text Analysis Rules for Clinical Records (1995)
Stephen Soderland, David Aronow, David Fisher, Jonathan Aseltine, Wendy Lehnert
This paper describes the BADGER text analysis system, which identifies concepts contained in a text based on linguistic context. A key component of BADGER is the CRYSTAL dictionary induction system...
Description of the UMass System as Used for MUC-6 (1995)
David Fisher, Stephen Soderland, Joseph McCarthy, Fangfang Feng, Wendy Lehnert
INTRODUCTION Information extraction research at the University of Massachusetts is based on portable, trainable language processing components. Some components are more effective than others, some...
Feasible Flows In Multicommodity Graphs (1995)
Holly Sue Zullo, Harvey Greenberg, Jennifer Ryan, David Fisher, J. Richard Lundgren, Gary Kochenberger
This thesis establishes the minimal representation of the necessary conditions for feasible supplies and demands for a given multicommodity network. The fundamental theorem is an extension of the...
Issues in Inductive Learning of Domain-Specific Text Extraction Rules (1995)
Stephen Soderland, David Fisher, Jonathan Aseltine, Wendy Lehnert
Domain-specific text analysis requires a dictionary of linguistic patterns that identify references to relevant information in a text. This paper describes CRYSTAL, a fully automated tool that...
Channel incision in dispersive clays : initiation and rehabilitation (1993)
Typescript (photocopy) Addendum inserted. Includes bibliographical references (leaves 224-243)
Applying Statistical Methods to Small Corpora: Benefitting from a Limited Domain (1992)
The application of statistical approaches to problems in natural language processing generally requires large #1,000,000+ words# corpora to produce useful results. In this paper we show that...
Applying Statistical Methods to Small Corpora: Benefitting from a Limited Domain (1992)
The application of statistical approaches to problems in natural language processing generally requires large (1,000,000+ words) corpora to produce useful results. In this paper we show that a...
University of Massachusetts: MUC-3 Test Results and Analysis (1991)
Wendy Lehnert, Claire Cardie, David Fisher, Ellen Riloff, Robert William S
We believe that the score reports we obtained for TST2 provide an accurate assessment of ou r system's capabilities insofar as they are consistent with the results of our own internal tests...
The strength of concrete in combined bending and torsion [microform] / (1950)
Thesis (doctoral)--University of London, 1950.
Being big or growing fast: systematic review of size and growth in infancy and later obesity
Baird, Janis, Fisher, David, Lucas, Patricia, Kleijnen, Jos, Roberts, Helen, Law, Catherine
Objectives To assess the association between infant size or growth and subsequent obesity and to determine if any association has been stable over time.
Dose Range Checking in a Computer Order Entry System
Rich, David, Menke, James, Fisher, David
We recently implemented a computer order entry (COE) system which uses decision support for dose range checking. In addition to providing decision support at the point of order entry via...
Being big or growing fast: systematic review of size and growth in infancy and later obesity
Baird, Janis, Fisher, David, Lucas, Patricia, Kleijnen, Jos, Roberts, Helen, Law, Catherine
Objectives To assess the association between infant size or growth and subsequent obesity and to determine if any association has been stable over time.
Dose Range Checking in a Computer Order Entry System
Rich, David, Menke, James, Fisher, David
We recently implemented a computer order entry (COE) system which uses decision support for dose range checking. In addition to providing decision support at the point of order entry via...
New light shed on fluid formation in the seminiferous tubules of the rat
In this study the effects of perfusing isolated seminiferous tubules of the testes are reported for the first time. Initial perfusion studies (fast rate perfusion) resulted in gross morphological...
Impact of Asylum on Receiving Countries
Martin, Susan F., Schoenholtz, Andrew I., Fisher, David
Whereas asylum seekers and the systems for adjudicating their claims to refugee status in developed countries have garnished considerable attention and, often, have been at the centre of political...
Topic Characterization of Full Length Texts Using Direct and Indirect Term Evidence
This project evaluates two families of algorithms that can be used to automatically classify general texts within a set of conceptual categories. The first family uses indirect evidence in the form...