14277112
A Methodology for Large-Scale Hardware Verification
We present a formal verification methodology for datapath-dominated hardware. This provides a systematic but flexible framework within which to organize the activities undertaken in large-scale verification efforts and to structure the associated code and proof-script artifacts. The methodology deploys a combination of model checking and lightweight theorem proving in higher-order logic, tightly integrated within a general-purpose functional programming language that allows the framework to be easily customized and also serves as a specification language. We illustrate the methodology--which has has proved highly effective in large-scale industrial trials--with the verification of an IEEE-compliant, extended precision floating-point adder.
5421455
Self-Consistency Checking
We introduce the notion of self-consistency checking, a new methodology for applying formal methods in the debugging process. Intuitively, self-consistency checks functional consistency of a circuit in two different modes or environments. Self-consistency can (1) simplify property verification and (2) enable the use of symbolic simulation in the absence of a concrete specification. We present a correctness model for property verification with self-consistency checking and the formal framework for the technique. Finally, we provide illustrative examples and partial verification results using self-consistency checking on circuits with many thousands of latches.
16794414
A Framework for Microprocessor Correctness Statements
Most verifications of out-of-order microprocessors compare state-machine-based implementations and specifications, where the specification is based on the instruction-set architecture. The different efforts use a variety of correctness statements, implementations, and verification approaches. We present a framework for classifying correctness statements about safety that is independent of implementation representation and verification approach. We characterize the relationships between the different statements and illustrate how existing and classical approaches fit within this framework.
7974229
Efficient validity checking for processor verification
We describe an efficient validity checker for the quantifier-free logic of equality with uninterpreted functions. This logic is well suited for verifying microprocessor control circuitry since it allows the abstraction of datapath values and operations. Our validity checker uses special data structures to speed up case splitting, and powerful heuristics to reduce the number of case splits needed. In addition, we present experimental results and show that this implementation has enabled the automatic verification of an actual high-level microprocessor description.
208909301
Parametric Representations of Boolean Constraints.
16718437
Practical Formal Verification in Microprocessor Design
Practical application of formal methods requires more than advanced technology and tools; it requires an appropriate methodology. A verification methodology for data-path-dominated hardware combines model checking and theorem proving in a customizable framework. This methodology has been effective in large-scale industrial trials, including verification of an IEEE-compliant floating-point adder.
6983154
Benchmarking Implementations of Functional Languages with 'Pseudoknot', a Float-Intensive Benchmark
Over 25 implementations of different functional languages are benchmarked using the same program, a floatingpoint intensive application taken from molecular biology. The principal aspects studied are compile time and execution time for the various implementations that were benchmarked. An important consideration is how the program can be modified and tuned to obtain maximal performance on each language implementation. 
With few exceptions, the compilers take a significant amount of time to compile this program, though most compilers were faster than the then current GNU C compiler (GCC version 2.5.8). Compilers that generate C or Lisp are often slower than those that generate native code directly: the cost of compiling the intermediate form is normally a large fraction of the total compilation time. 
There is no clear distinction between the runtime performance of eager and lazy implementations when appropriate annotations are used: lazy implementations have clearly come of age when it comes to implementing largely strict applications, such as the Pseudoknot program. The speed of C can be approached by some implemtations, but to achieve this performance, special measures such as strictness annotations are required by non-strict implementations. 
The benchmark results have to be interpreted with care. Firstly, a benchmark based on a single program cannot cover a wide spectrum of 'typical' applications.j Secondly, the compilers vary in the kind and level of optimisations offered, so the effort required to obtain an optimal version of the program is similarly varied.
15205488
Query word deletion prediction
Web search query logs contain traces of users' search modifications. One strategy users employ is deleting terms, presumably to obtain greater coverage. It is useful to model and automate term deletion when arbitrary searches are conjunctively matched against a small hand constructed collection, such as a hand-built hierarchy, or collection of high-quality pages matched with key phrases. Queries with no matches can have words deleted till a match is obtained. We provide algorithms which perform substantially better than the baseline in predicting which word should be deleted from a reformulated query, for increasing query coverage in the context of web search on small high-quality collections.
572074
Building mosaics from video using MPEG motion vectors
Abstract : In this paper, we present a novel way of creating mosaics from an MPEG video sequence. Two original aspects of our work are that (1) we explicitly compute camera motion between frames and (2) we deduce the camera motion directly from the motion vectors encoded in the MPEG video stream. This enables us to create mosaics more simply and quickly than with other methods.
17471934
Designing a trace format for heap allocation events
Dynamic storage allocation continues to play an important role in the performance and correctness of systems ranging from user productivity software to high-performance servers. While algorithms for dynamic storage allocation have been studied for decades, much of the literature is based on measuring the performance of benchmark programs unrepresentative of many important allocation-intensive workloads. Furthermore, to date no standard has emerged or been proposed for publishing and exchanging representative allocation workloads. In this paper, we describe a preliminary design of a trace format for such workloads and investigate its effectiveness at representing large allocation traces. Our proposal allows for a flexible encoding of information in the trace to achieve greater compression. We evaluate our preliminary design in two dimensions. First, we measure how effective these encodings are at reducing trace size. Second we consider how a meta-level specification language could be used to describe such formats and to generate trace readers and writers automatically.
6044805
GCspy: an adaptable heap visualisation framework
GCspy is an architectural framework for the collection, transmission, storage and replay of memory management behaviour. It makes new contributions to the understanding of the dynamic memory behaviour of programming languages (and especially object-oriented languages that make heavy demands on the performance of memory managers). GCspy's architecture allows easy incorporation into any memory management system: it is not limited to garbage-collected languages. It requires only small changes to the system in which it is incorporated but provides a simple to use yet powerful data-gathering API. GCspy scales to allow very large heaps to be visualised effectively and efficiently. It allows already-running, local or remote systems to be visualised and those systems to run at full speed outside the points at which data is gathered. GCspy's visualisation tool presents this information in a number of novel ways.Deep understanding of program behaviour is essential to the design of the next generation of garbage collectors and explicit allocators. Until now, no satisfactory tools have been available to assist the implementer in gaining an understanding of heap behaviour. GCspy has been demonstrated to be a practical solution to this dilemma. It has been used to analyse production Java virtual machines running applications of realistic sizes. Its use has revealed important insights into the interaction between application program and JVM and has led to the development of better garbage collectors.