Performance-Based Specifications: Exploring When They Work and Why

There is extensive research and attention on innovation and sustainable public procurement (SPP) in the European Union at present, with the 2014 revision of the Procurement Directives, the Innovation Union strategy and other European Union policy initiatives. This report seeks to contribute to this discussion through the investigation of the use of performance based specifications (PBSs) in public procurement in the European Union and the United States. The report outlines the benefits and limitations of the use of PBSs, even in the most "progressive" public procurement environments, such as the Netherlands, particularly around their ability to support sustainable development goals and deliver environmental benefits for a procuring authority, such as energy and resource efficiency. Additionally, this report aims to identify the sectors in which the enabling conditions for the successful use of PBSs in public procurement are in place and to understand what policies and regulations are needed to promote the use of PBSs in public tenders and public procurement framework agreements

Monitoring and Assessing the Use of External Quality Review Organizations to Improve Services for Young Children: A Toolkit for State Medicaid Agencies

Assesses the extent to which states use external quality review organizations in studying the quality of preventive and developmental services for young children enrolled in Medicaid, and provides guidance on determining their scope of work

Specifying Reusable Components

Reusable software components need expressive specifications. This paper outlines a rigorous foundation to model-based contracts, a method to equip classes with strong contracts that support accurate design, implementation, and formal verification of reusable components. Model-based contracts conservatively extend the classic Design by Contract with a notion of model, which underpins the precise definitions of such concepts as abstract equivalence and specification completeness. Experiments applying model-based contracts to libraries of data structures suggest that the method enables accurate specification of practical software

Towards Realizability Checking of Contracts using Theories

Virtual integration techniques focus on building architectural models of systems that can be analyzed early in the design cycle to try to lower cost, reduce risk, and improve quality of complex embedded systems. Given appropriate architectural descriptions and compositional reasoning rules, these techniques can be used to prove important safety properties about the architecture prior to system construction. Such proofs build from "leaf-level" assume/guarantee component contracts through architectural layers towards top-level safety properties. The proofs are built upon the premise that each leaf-level component contract is realizable; i.e., it is possible to construct a component such that for any input allowed by the contract assumptions, there is some output value that the component can produce that satisfies the contract guarantees. Without engineering support it is all too easy to write leaf-level components that can't be realized. Realizability checking for propositional contracts has been well-studied for many years, both for component synthesis and checking correctness of temporal logic requirements. However, checking realizability for contracts involving infinite theories is still an open problem. In this paper, we describe a new approach for checking realizability of contracts involving theories and demonstrate its usefulness on several examples.Comment: 15 pages, to appear in NASA Formal Methods (NFM) 201

Multilevel Contracts for Trusted Components

This article contributes to the design and the verification of trusted components and services. The contracts are declined at several levels to cover then different facets, such as component consistency, compatibility or correctness. The article introduces multilevel contracts and a design+verification process for handling and analysing these contracts in component models. The approach is implemented with the COSTO platform that supports the Kmelia component model. A case study illustrates the overall approach.Comment: In Proceedings WCSI 2010, arXiv:1010.233

Contracts as specifications for dynamical systems in driving variable form

This paper introduces assume/guarantee contracts on continuous-time control systems, hereby extending contract theories for discrete systems to certain new model classes and specifications. Contracts are regarded as formal characterizations of control specifications, providing an alternative to specifications in terms of dissipativity properties or set-invariance. The framework has the potential to capture a richer class of specifications more suitable for complex engineering systems. The proposed contracts are supported by results that enable the verification of contract implementation and the comparison of contracts. These results are illustrated by an example of a vehicle following system.Comment: 8 pages, 2 figures; minor changes in the final version, as accepted for publication in the Proceedings of the 2019 European Control Conference, Naples, Ital