42148814
Using GALS architecture to reduce the impact of long wire delay on FPGA performance
14531853
A novel asynchronous FPGA architecture design and its performance evaluation
This paper proposes GAPLA: a globally asynchronous locally synchronous programmable logic array architecture. The whole FPGA area is divided into locally synchronous blocks wrapped with asynchronous I/O interfaces. Data communications between synchronous blocks are controlled by 2-phase handshaking signals under bundled-data delay assumption. The size and shape of each locally synchronous block are programmable so that different modules in a design can be effectively implemented. By dividing the FPGA area into smaller blocks, the delays of long interconnect wires, which could easily dominate other delays in conventional FPGAs, only come into picture when there are communications between blocks. Therefore, each block could run at higher speed. The area overhead of adopting the GALS style in GAPLA architecture is estimated to be very small (about 7%). Experimental results show an up to 55% performance improvement compared to the conventional FPGAs.
17179157
Conditional Functional Dependencies for Data Cleaning
We propose a class of constraints, referred to as conditional functional dependencies (CFDs), and study their applications in data cleaning. In contrast to traditional functional dependencies (FDs) that were developed mainly for schema design, CFDs aim at capturing the consistency of data by incorporating bindings of semantic ally related values. For CFDs we provide an inference system analogous to Armstrong's axioms for FDs, as well as consistency analysis. Since CFDs allow data bindings, a large number of individual constraints may hold on a table, complicating detection of constraint violations. We develop techniques for detecting CFD violations in SQL as well as novel techniques for checking multiple constraints in a single query. We experimentally evaluate the performance of our CFD-based methods for inconsistency detection. This not only yields a constraint theory for CFDs but is also a step toward a practical constraint-based method for improving data quality.
42442258
An approach to animating Z specifications
This paper presents the ZANS approach to animating a large subset of Z specifications. Unlike most other animation approaches that are based on functional or logical programming paradigms, the approach presented transforms the specifications into an imperative intermediate language, which can also serve as the basis of code synthesis from Z specifications. ZANS is showing promise of being an effective tool for requirements validation and assisting students learning Z specification languages.
4599441
A Hypothesis-Based Approach to Detecting Runtime Violations
We have developed an approach to apply formal methods to represent program source code as a model and use an automated theorem prover to detect runtime violations by doing static analysis. Unlike other proof-based program verification approaches, this approach is based on a hypothesis to develop the implicit specification information, such as invariants, preconditions, postconditions, then using an automated theorem prover to verify the correctness of each statement in the program. Our research work can catch those runtime exceptions that are beyond the capability of control flow-based analysis in compilers.
44437581
Visual languages and software specifications
The important issues and major features of visual languages are summarized, and their impact on software engineering, especially software specification techniques, are discussed. The potential of using visual languages for software specifications to improve software reliability, modifiability, reusability, and understandability is also considered.<<ETX>>
13944177
A pragmatic approach to formalizing object-oriented modeling and development
Despite recent developments in formal methods, these methods have yet to enter the mainstream of the software industry. We first examine the pragmatic obstacles to making formal methods practical and usable. Then we present a pragmatic approach to integrate a popular object oriented modeling notation UML and a popular formal notation Z. Our approach is distinctive in its emphasis on overcoming the practical obstacles. We also present a light weight supporting tool for our approach. A prototype of the supporting tool is completed. It allows us to demonstrate the feasibility and capability of our approach.