Now showing items 93-112 of 245

    • Fast Approximating Triangulation of Large Scattered Datasets 

      Warren, Joe; Weimer, Henrik (1997-09-03)
      This report describes algorithms and data-structures for the fast construction of three-dimensional triangulations from large sets of scattered data-points. The triangulations have a guaranteed error bound, i.e. all the data-points lie within a pre-specified distance from the triangulation. Three different methods for choosing triangulation vertices ...
    • Finding Solutions of the Inverse Kinematics Problems in Computer-aided Drug Design 

      Kavraki, Lydia E.; Zhang, Ming (2002-01-25)
      The efficient computation of low-energy molecular conformations is of critical importance to problems ranging from protein folding to computer-assisted drug design. Despite the growing number of papers on three-dimensional conformational search, several questions remain open. In this paper we investigate one such question relating to molecular inverse ...
    • Finding the Evidence in Tamper-Evident Logs 

      Sandler, Daniel; Derr, Kyle; Crosby, Scott A.; Wallach, Dan S. (2008-01-23)
      Secure logs are powerful tools for building systems that must resist forgery, prove temporal relationships, and stand up to forensic scrutiny. The proofs of order and integrity encoded in these tamper-evident chronological records, typically built using hash chaining, may be used by applications to enforce operating constraints or sound alarms at ...
    • Fixpoint Logics, Relational Machines, and Computational Complexity 

      Abiteboul, Serge; Vardi, Moshe Y.; Vianu, Victor (1996-10-11)
      We establish a general connection between fixpoint logic and complexity. On one side, we have fixpoint logic, parameterized by the choices of 1st-order operators (inflationary or noninflationary) and iteration constructs (deterministic, nondeterministic, or alternating). On the other side, we have the complexity classes between P and EXPTIME. Our ...
    • Fully Abstract Semantics for Observably Sequential Languages 

      Cartwright, Robert; Curien, Pierre-Louis; Felleisen, Matthias (1994-01)
      One of the major challenges in denotational semantics is the construction of a fully abstract semantics for a higher-order sequential programming language. For the past fifteen years, research on this problem has focused on developing a semantics forPCF, an idealized functional programming language based on the typed lambda calculus. Unlike most ...
    • Garbage Collector Memory Accounting in Language-Based Systems 

      Price, David W.; Rudys, Algis; Wallach, Dan S. (2003-11-11)
      Language run-time systems are often called upon to safely execute mutually distrustful tasks within the same runtime, protecting them from other tasks' bugs or otherwise hostile behavior. well-studied access controls exist in systems such as Java to prevent unauthorized reading or writing of data, but techniques to measure and control resource usage ...
    • Gleaning Network-Wide Congestion Information from Packet Markings 

      Dinu, Florin; Ng, T. S. Eugene (2010-06-29)
      Distributed control protocols routinely have to operate oblivious of dynamic network information for scalability or complexity reasons. However, more informed protocols are likely to make more intelligent decisions. We argue that protocols can leverage dynamic congestion information without suffering the mentioned penalties. In this paper we show ...
    • Gradual Typing: Isabelle/Isar Formalization 

      Siek, Jeremy; Taha, Walid (2006-04-07)
      This report formalizes a gradual type system using the Isabelle/Isar proof language and proof assistant. Gradual typing combines static typing and dynamic typing in the same language, allowing a programmer to gradual migrate portions of a program between the two typing disciplines.
    • Hack-a-Vote: Demonstrating Security Issues with Electronic Voting Systems 

      Bannet, Jonathan; Price, David W.; Rudys, Algis; Singer, Justin; Wallach, Dan S. (2003-11-21)
      A representative democracy depends on a universally trusted voting system for the election of representatives; voters need to believe that their votes count, and all parties need to be convinced that the winner and loser of the election were declared legitimately. Direct recording electronic (DRE)voting systems are increasingly being deployed to fill ...
    • Hierarchical Attribute Grammars: Dialects, Applications and Evaluation Algorithms 

      Carle, Alan (1992-05)
      Although attribute grammars have been applied successfully to the specification of many different phases of analysis and transformation of complex language processing systems, including type checking, data flow analysis, constant propagation and dead code elimination, little success has been achieved in applying attribute grammars to the specification ...
    • How Much Do Unstated Problem Constraints Limit Deep Robotic Reinforcement Learning? 

      Lewis, W. Cannon II; Moll, Mark; Kavraki, Lydia E. (2019)
      Deep Reinforcement Learning is a promising paradigm for robotic control which has been shown to be capable of learning policies for high-dimensional, continuous control of unmodeled systems. However, Robotic Reinforcement Learning currently lacks clearly defined benchmark tasks, which makes it difficult for researchers to reproduce and compare against ...
    • HPCTOOLKIT: Tools for performance analysis of optimized parallel programs 

      Adhianto, L.; Banerjee, S.; Fagan, M.; Krentel, M.; Marin, G.; (2008-10-03)
      HPCTOOLKIT is an integrated suite of tools that supports measurement, analysis, attribution, and presentation of application performance for both sequential and parallel programs. HPCTOOLKIT can pinpoint and quantify scalability bottlenecks in fully-optimized parallel programs with a measurement overhead of only a few percent. Recently, new capabilities ...
    • Hybrid Dixon Resultants 

      Chionh, Eng-Wee; Goldman, Ronald; Zhang, Ming (1998-05-13)
      Dixon [1908] describes three distinct homogeneous determinant representations for the resultant of three bivariate polynomials of bidegree(m,n). These Dixon resultants are the determinants of matrices of orders 6mn, 3mn and 2mn, and the entries of these matrices are respectively homogeneous of degrees 1, 2, and 3 in the coefficients of the original ...
    • Implementing a Static Debugger for a First-Order Functional Programming Language 

      Felleisen, Matthias; Steckler, Paul A. (2001-04)
      A static debugger assists a programmer in finding potential errors in programs. The key to a static debugger is set-based analysis (SBA). Many authors have described formulations of SBA, but leave open gaps among that theory, its implementation, and its use for a particular purpose. An implementation needs to confront these practical issues. While ...
    • Implementing linear algebra algorithms on high performance architectures 

      Aleksandrov, Lyudmil; Candev, Michael; Djidjev, Hristo N. (1997-07-25)
      In this paper we consider the data distribution and data movement issues related to the solution of the basic linear algebra problems on high performance systems. The algorithms we discuss in details are the Gauss andGauss-Jordan methods for solving a system of linear equations, the Cholesky's algorithm for LL^T-factorization, and QR-factorization ...
    • Implementing the Top-Down Close Algorithm on the TI 6200 Architecture 

      Dasgupta, Anshuman (2002-12-12)
      Partitioned register-set architectures pose a challenge to standard scheduling algorithms. To create an efficient schedule, an instruction scheduler for such an architecture must consider the location of an operand in the register file, the availability of the inter-cluster data bus, and the profitability of a inter-cluster copy instruction. This ...
    • Implicitly Heterogeneous Multi-stage Programming 

      Eckhardt, Jason; Kaiabachev, Roumen; Pašalić, Emir; Swadi, Kedar; Taha, Walid (2005-04-16)
      Previous work on semantics-based multi-stage programming (MSP) language design focused on homogeneous languages designs, where the generating and the generated languages are the same. Homogeneous designs simply add a hygienic quasi-quotation and evaluation mechanism to a base language. An apparent disadvantage of this approach is that the programmer ...
    • Improving Effective Bandwidth through Compiler Enhancement of Global and Dynamic Cache Reuse 

      Ding, Chen (2000-01-21)
      While CPU speed has been improved by a factor of 6400 over the past twenty years, memory bandwidth has increased by a factor of only 139 during the same period. Consequently, on modern machines the limited data supply simply cannot keep a CPU busy, and applications often utilize only a few percent of peak CPU performance. The hardware solution, which ...
    • Improving Memory Hierarchy Performance for Irregular Applications 

      Kennedy, Ken; Mellor-Crummey, John; Whalley, David (1999-03-10)
      The gap between CPU speed and memory speed in modern computer systems is widening as new generations of hardware are introduced. Loop blocking and prefetching transformations help bridge this gap for regular applications; however, these techniques don't deal well with irregular applications. This paper investigates using data and computation reordering ...
    • Improving Performance with Integrated Program Transformations 

      Jin, Guohua; Mellor-Crummey, John; Qasem, Apan (2004-09-09)
      Achieving a high fraction of peak performance on today’s computer systems is difficult for complex scientific applications. To do so, an application’s characteristics must be tailored to exploit the characteristics of its target architecture. Today, commercial compilers do not adequately tailor programs automatically; thus, application scientists ...