A Tool for Intersecting Context-Free Grammars and Its Applications

This paper describes a tool for intersecting context-free grammars. Since this problem is undecidable the tool follows a refinement-based approach and implements a novel refinement which is complete for regularly separable grammars. We show its effectiveness for safety verification of recursive multi-threaded programs

Analyzing Array Manipulating Programs by Program Transformation

We explore a transformational approach to the problem of verifying simple array-manipulating programs. Traditionally, verification of such programs requires intricate analysis machinery to reason with universally quantified statements about symbolic array segments, such as "every data item stored in the segment A[i] to A[j] is equal to the corresponding item stored in the segment B[i] to B[j]." We define a simple abstract machine which allows for set-valued variables and we show how to translate programs with array operations to array-free code for this machine. For the purpose of program analysis, the translated program remains faithful to the semantics of array manipulation. Based on our implementation in LLVM, we evaluate the approach with respect to its ability to extract useful invariants and the cost in terms of code size

CRISTOPH – A cluster-randomised intervention study to optimise the treatment of patients with hypertension in General Practice

<p>Abstract</p> <p>Background</p> <p>Recent guidelines for the management of hypertension focus on treating patients according to their global cardiovascular risk (CVR), rather than strictly keeping blood pressure, or other risk factors, below set limit values. The objective of this study is to compare the effect of a simple versus a complex educational intervention implementing this new concept among General Practitioners (GPs).</p> <p>Methods/design</p> <p>A prospective longitudinal cluster-randomised intervention trial with 94 German GPs consecutively enroling 40 patients each with known hypertension. All GPs then received a written manual specifically developed to transfer the global concept of CVR into daily General Practice. After cluster-randomisation, half of the GPs additionally received a clinical outreach visit, with a trained peer discussing with them the concept of global CVR referring to example study patients from the respective GP. Main outcome measure is the improvement of calculated CVR six months after intervention in the subgroup of patients with high CVR (but no history of cardiovascular disease), defined as 10-year-mortality ≥ 5% employing the European SCORE formula. Secondary outcome measures include the intervention's effect on single risk factors, and on prescription rates of drugs targeting CVR. All outcome measures are separately studied in the three subgroups of patients with 1. high CVR (defined as above), 2. low CVR (SCORE < 5%), and 3. a history of cardiovascular disease. The influence of age, sex, social status, and the perceived quality of the respective doctor-patient-relation on the effects will be examined.</p> <p>Discussion</p> <p>To our knowledge, no other published intervention study has yet evaluated the impact of educating GPs with the goal to treat patients with hypertension according to their global cardiovascular risk.</p> <p>Trial registration</p> <p>ISRCTN44478543</p

Inferring Congruence Equations using SAT: 20th International Conference, CAV 2008 Princeton, NJ, USA, July 7-14, 2008 Proceedings

This paper proposes a new approach for deriving invariants that are systems of congruence equations where the modulo is a power of 2. The technique is an amalgam of SAT-solving, where a propositional formula is used to encode the semantics of a basic block, and abstraction, where the solutions to the formula are systematically combined and summarised as a system of congruence equations. The resulting technique is more precise than existing congruence analyses since a single optimal transfer function is derived for a basic block as a whole

Places for learning engineering: a preliminary report on informal learning spaces

This is a report on an investigation of undergraduate engineering learning spaces that were newly introduced in 2008. The new spaces include formal learning spaces designed to enable student-centred, small group learning, and informal café-style spaces. The project investigates the research question: Does an availability of spaces for informal learning lead to an increase in behaviours that one might expect to be conducive to increased informal or collaborative learning? The initial findings from the survey data suggest that there may be some increased use of informal learning spaces if they are made available to students