Rodin: an open toolset for modelling and reasoning in Event-B

Event-B is a formal method for system-level modelling and analysis. Key features of Event-B are the use of set theory as a modelling notation, the use of refinement to represent systems at different abstraction levels and the use of mathematical proof to verify consistency between refinement levels. In this article we present the Rodin modelling tool that seamlessly integrates modelling and proving. We outline how the Event-B language was designed to facilitate proof and how the tool has been designed to support changes to models while minimising the impact of changes on existing proofs. We outline the important features of the prover architecture and explain how well-definedness is treated. The tool is extensible and configurable so that it can be adapted more easily to different application domains and development methods

Applying Formal Methods to Networking: Theory, Techniques and Applications

Despite its great importance, modern network infrastructure is remarkable for the lack of rigor in its engineering. The Internet which began as a research experiment was never designed to handle the users and applications it hosts today. The lack of formalization of the Internet architecture meant limited abstractions and modularity, especially for the control and management planes, thus requiring for every new need a new protocol built from scratch. This led to an unwieldy ossified Internet architecture resistant to any attempts at formal verification, and an Internet culture where expediency and pragmatism are favored over formal correctness. Fortunately, recent work in the space of clean slate Internet design---especially, the software defined networking (SDN) paradigm---offers the Internet community another chance to develop the right kind of architecture and abstractions. This has also led to a great resurgence in interest of applying formal methods to specification, verification, and synthesis of networking protocols and applications. In this paper, we present a self-contained tutorial of the formidable amount of work that has been done in formal methods, and present a survey of its applications to networking.Comment: 30 pages, submitted to IEEE Communications Surveys and Tutorial

Program transformations using temporal logic side conditions

This paper describes an approach to program optimisation based on transformations, where temporal logic is used to specify side conditions, and strategies are created which expand the repertoire of transformations and provide a suitable level of abstraction. We demonstrate the power of this approach by developing a set of optimisations using our transformation language and showing how the transformations can be converted into a form which makes it easier to apply them, while maintaining trust in the resulting optimising steps. The approach is illustrated through a transformational case study where we apply several optimisations to a small program

Collaborative software agents support for the texpros document management system

This dissertation investigates the use of active rules that are embedded in markup documents. Active rules are used in a markup representation by integrating Collaborative Software Agents with TEXPROS (abbreviation for TEXt PROcessing System) [Liu and Ng 1996] to create a powerful distributed document management system. Such markup documents with embedded active rules are called Active Documents. For fast retrieval purposes, when we need to generate a customized Internet folder organization, we first define the Folder Organization Query Language (FO-QL) to solve data categorization problems. FO-QL defines the folder organization query process that automatically retrieves links of documents deposited into folders and then constructs a folder organization in either a centralized document repository or multiple distributed document repositories. Traditional documents are stored as static data that do not provide any dynamic capabilities for accessing or interacting with the document environment. The dynamic and distributed nature of both markup data and markup rules do not merely respond to requests for information, but intelligently anticipate, adapt, and actively seek ways to support the computing processes. This outcome feature conquers the static nature of the traditional documents. An Office Automation Definition Language (OADL) with active rules is defined for constructing the TEXPROS \u27s dual modeling approach and workflow events representation. Active Documents are such agent-supported OADL documents. With embedded rules and self-describing data features, Active Documents provide capability of collaborative interactions with software agents. Data transformation and data integration are both data processing problems but little research has focused on the markup documents to generate a versatile folder organization. Some of the research merely provides manual browsing in a document repository to find the right document. This browsing is time consuming and unrealistic, especially in multiple document repositories. With FO-QL, one can create a customized folder organization on demand