644 research outputs found
Determinants of Private Afforestation in the Republic of Ireland
No full textThis paper employs a panel regression analysis using county-level data to quantify the relative importance of competing forestry and agricultural policy incentives in explaining trends in private afforestation in Ireland. It concludes that an increase in the level of up front payments to planters is the most cost efficient way of increasing planting levels. The introduction of the Irish agri-environment programme REPS has contributed to a significant decline in the level of forestry planting and offset the recent increases in the level of forestry grants and premia. Several policy reforms to encourage forestry planting in Ireland are proposed, including greater integration of forestry with the REPS scheme and increasing the value of the initial payment which farmers receive.
Algebraic properties of program integration
No full textAbstract. The need to integrate several versions of a program into a common one arises frequently, but it is a tedious and time consuming task to merge programs by hand. The program-integration algorithm proposed by Horwitz, Prins, and Reps provides a way to create a semantics-based tool for integrating a base program with two or more variants. The integration algorithm is based on the assumption that any change in the behavior, rather than the text, of a program variant is significant and must be incorporated in the merged program. An integration system based on this algorithm will determine whether the variants incorporate interfering changes, and, if they do not, create an integrated program that includes all changes as well as all features of the base program that are preserved in all variants. To determine this information, the algorithm employs a program representation that is similar to the program dependence graphs that have been used previously in vectorizing and parallelizing compilers. This paper studies the algebraic properties of the program-integration operation, such as whether there are laws of associativity and distributivity. (For example, in this context associativity means: “If three variants of a given base are to be integrated by a pair of two-variant integrations, the same result is produced no matter which two variants are integrated first.”) To answer such questions, we reformulate the Horwitz-Prins-Reps integration algorithm as an operation in a Brouwerian algebra constructed from sets of dependence graphs. (A Brouwerian algebra is a distributive lattice with an operation a. − b characterized by a. ¡
Analysis of Executables: Benefits and Challenges
No full textThe analysis of executables is concerned with extracting information from a binary program typically, though not exclusively, with program analysis techniques based on abstract interpretation. This topic has risen to prominence due to the need to audit code, developed by third parties for which the source is unavailable. Moreover, compilers are themselves a source of bugs, hence the need to scrutinise and systematically examine executables
Demonstration Of A Prototype Tool For Program Integration Thomas Reps
No full textThis paper illustrates a sample session with a preliminary implementation of a program-integration tool. The tool has been embedded in a program editor created using the Synthesizer Generator, a meta-system for creating interactive, language-based program development systems. Information maintained by the editor front-end is used to construct dependence graphs. An integration command added to the editor invokes the integration algorithm on the dependence graphs, reports whether the variant programs interfere, and, if there is no interference, builds the integrated progra
A Run-Time Type-Checking Debugger for C
No full textThis document outlines progress to date on the run-time type-checking project funded in part by IBM. The project has been carried out during the last year by Alexey Loginov and Suan Yong, under the supervision of Professors Susan Horwitz and Thomas Reps
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Decision Procedures and Abstract Interpretation (Dagstuhl Seminar 14351)
No full textThis report documents the program and the outcomes of Dagstuhl Seminar 14351 "Decision Procedures and Abstract Interpretation". The seminar brought together practitioners and reseachers in abstract interpretation and decision procedures.
The meeting highlighted the connections between the two disciplines, and created new links between the two research communities. Joint activities were also conducted with the participants of Dagstuhl Seminar 14352 "Next Generation Static Software Analysis Tools", which was held concurrently
TSL: A System for Generating Abstract Interpreters and its Application to Machine-Code Analysis
No full textThis paper describes the design and implementation of a system, called TSL (for "Transformer Specification Language"), that provides a systematic solution to the problem of creating retargetable tools for analyzing machine code. TSL is a tool generator--i.e., a meta-tool--that automatically creates different abstract interpreters for machine-code instruction sets. The most challenging technical issue that we faced in designing TSL was how to automate the generation of the set of abstract transformers for a given abstract interpretaton of a given instruction set. From a description of the concrete operational semantics of an instruction set, together with the datatypes and operations that define an abstract domain, TSL automatically creates the set of abstract transformers for the instructions of the instruction set. TSL advances the state of the art in program analysis because it provides two dimensions of parameterizability: (i) a given analysis component can be retargeted to different instruction sets; (ii) multiple analysis components can be created automatically from a single specification of the concrete operational semantics of the language to be analyzed. TSL is an abstract-transformer-generator generator. The paper describes the principles behind TSL, and discusses how one uses TSL to develop different abstract interpreters
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