Enhanced sharing analysis techniques: a comprehensive evaluation

Sharing, an abstract domain developed by D. Jacobs and A. Langen for the analysis of logic programs, derives useful aliasing information. It is well-known that a commonly used core of techniques, such as the integration of Sharing with freeness and linearity information, can significantly improve the precision of the analysis. However, a number of other proposals for refined domain combinations have been circulating for years. One feature that is common to these proposals is that they do not seem to have undergone a thorough experimental evaluation even with respect to the expected precision gains. In this paper we experimentally evaluate: helping Sharing with the definitely ground variables found using Pos, the domain of positive Boolean formulas; the incorporation of explicit structural information; a full implementation of the reduced product of Sharing and Pos; the issue of reordering the bindings in the computation of the abstract mgu; an original proposal for the addition of a new mode recording the set of variables that are deemed to be ground or free; a refined way of using linearity to improve the analysis; the recovery of hidden information in the combination of Sharing with freeness information. Finally, we discuss the issue of whether tracking compoundness allows the computation of more sharing information

Semantics-based analysis for optimizing compilation of concurrent programs

制度:新 ; 文部省報告番号:甲2127号 ; 学位の種類:博士(情報科学) ; 授与年月日:2005/12/22 ; 早大学位記番号:新412

The determination of road sections by computer for use in road design

A brief resume of ,recent developments in the design of roads is given with special reference to the increasing part played by automated methods by means of which higher degrees of optimization may be achieved. Flow charts illustrating road design demonstrate the relative importance of the determination of the transverse road section by computer. The finished transverse road section, called a template, consists of a central portion and the outer sloped cut and fill banks. The central portion covers the carriageway(s) and shoulders, the shape of which is predetermined by the geometric .design of the road surface and is independent of ground shape. The outer sloped banks, called the side-drain template, are dependent upon the position of the ground surface in relation to the predetermined central portion. When a road is to be built, the road authority usually prescribes the final transverse shape of the road by specifying a standard road template. At every point along the road a specific template can then be determined in accordance with the standard template. However, problems are experienced because certain available computer programs are unable to execute the side-drain portion of the standard road template correctly while earthwork quantities are being calculated. Several available programs are investigated with regard to the procedures adopted by them for the selection of appropriate road side-drain templates. Deficiencies in these programs are noted. A general solution to the problem of the logical determination of road sections by computer, namely, the method of the locus of the slope stake point, is introduced and elucidated. The success of the method is confirmed by the presentation of the completely operative computer program SHARM for the calculation of road earthworks quantities: The use of the program is demonstrated by a short sample run. Limitations of the method of the locus of the slope stake point and of the SHARM program are noted, and finally some future developments are discussed

On the Automated Verification of Web Applications with Embedded SQL

A large number of web applications is based on a relational database together with a program, typically a script, that enables the user to interact with the database through embedded SQL queries and commands. In this paper, we introduce a method for formal automated verification of such systems which connects database theory to mainstream program analysis. We identify a fragment of SQL which captures the behavior of the queries in our case studies, is algorithmically decidable, and facilitates the construction of weakest preconditions. Thus, we can integrate the analysis of SQL queries into a program analysis tool chain. To this end, we implement a new decision procedure for the SQL fragment that we introduce. We demonstrate practical applicability of our results with three case studies, a web administrator, a simple firewall, and a conference management system