Programmers' performance on structured versus nonstructured function definitions

A control-flow model for functional programs is used in an experimental comparison of the performance of programmers on structured versus nonstructured Miranda function definitions. The performance is taken as a measure of the comprehensibility of functional programs. The experimental set-up is similar to the Scanlan study (1989). However, in the present study, a two-factor repeated measures design is used in the statistical analysis. The control-flow model appears to be useful in the shaping of the experiment. A significantly better performance has been found for structured function definitions on both dependent variables: the time needed to answer questions about the function definitions and the proportion correct answers. Moreover, for structured function definitions, a counter-intuitive result has been obtained: there are significantly fewer errors in larger definitions than in smaller ones

Combining behavioural types with security analysis

Today's software systems are highly distributed and interconnected, and they increasingly rely on communication to achieve their goals; due to their societal importance, security and trustworthiness are crucial aspects for the correctness of these systems. Behavioural types, which extend data types by describing also the structured behaviour of programs, are a widely studied approach to the enforcement of correctness properties in communicating systems. This paper offers a unified overview of proposals based on behavioural types which are aimed at the analysis of security properties

Commentary on Child Welfare Waivers: The Stakes for Families

The purpose of this piece is to provide commentary of an article, Child Welfare Waivers: The Stakes for Your State, that discusses the recent reauthorization of the Title IV-E Child Welfare Waivers. The article provides an overview of funds available to the states for child welfare programs and their intended purpose and restrictions placed on use. As structured, the present system rewards states monetarily for maintaining foster care. Research from waiver programs shows promising results for improved outcomes at the same or lower financial cost by utilizing safe, proven alternatives to the current foster care system. Waiver funds also protect the financial commitment to child welfare because state legislative budget slashing in this area will result in the loss of Federal funding. The independent analysis required with the grant of a waiver must be maintained to provide ongoing analysis and oversight of the increase spending flexibility. Stakeholders must be aware of the program and its results and use these funds as an opportunity to assess new concepts and apply programs best suited to the needs of children in their state. Allowing those “on the ground” to determine appropriate programming and careful result assessment may be the best means for protecting children, preserving families and doing both in a manner that makes the most efficient use of available resources

Flowchart Programs, Regular Expressions, and Decidability of Polynomial Growth-Rate

We present a new method for inferring complexity properties for a class of programs in the form of flowcharts annotated with loop information. Specifically, our method can (soundly and completely) decide if computed values are polynomially bounded as a function of the input; and similarly for the running time. Such complexity properties are undecidable for a Turing-complete programming language, and a common work-around in program analysis is to settle for sound but incomplete solutions. In contrast, we consider a class of programs that is Turing-incomplete, but strong enough to include several challenges for this kind of analysis. For a related language that has well-structured syntax, similar to Meyer and Ritchie's LOOP programs, the problem has been previously proved to be decidable. The analysis relied on the compositionality of programs, hence the challenge in obtaining similar results for flowchart programs with arbitrary control-flow graphs. Our answer to the challenge is twofold: first, we propose a class of loop-annotated flowcharts, which is more general than the class of flowcharts that directly represent structured programs; secondly, we present a technique to reuse the ideas from the work on tructured programs and apply them to such flowcharts. The technique is inspired by the classic translation of non-deterministic automata to regular expressions, but we obviate the exponential cost of constructing such an expression, obtaining a polynomial-time analysis. These ideas may well be applicable to other analysis problems.Comment: In Proceedings VPT 2016, arXiv:1607.0183

Models of Service and Civic Education: An Occasional Paper of the Project on Integrating Service and Academic Study

Citizenship education is generally recognized as the primary reason for supporting service-learning on college campuses. Assumptions about citizenship affect how programs and curricula are structured. An analysis of programs around the country identified four sets of core assumptions about civic education that inform service-learning courses and programs. This paper is intended to be useful to faculty designing service-learning courses and to those who want to make explicit multiple frameworks for understanding service experiences