J\u27Accuse! ATTRIBUTION OF BLAME WHEN SOFTWARE IS AN ACTOR (11)

The desire for closure after an accident may be hastened by the attribution of blame. This is particularly attractive in situations where complex factors may distance the understanding of attribution from those who may not be familiar with all vectors towards the failure causing the accident. The keyword here is ‘accident’ suggesting that deliberate action/s have not been the cause. It is pertinent to establish systems – such as those responsible for process control where it may be argued that the risk of remote, malicious intervention was not readily foreseeable at the time of their realization. The paper puts forward a framework for the elaboration of requirements with a focus on organizational factors as a way of teasing out problems in early development. The objective is to achieve a sense of assurance that due diligence is both done and seen to be done in an increasingly non-deterministic operational environment

Feature-Oriented Modelling Using Event-B

Event-B is a formal method for specification and verification of reactive systems. Its Rodin toolkit provides comprehensive support for modelling, refinement and analysis using theorem proving, animation and model checking. There has always been a need to reuse existing models and their associated proofs when modelling related systems to save time and effort. Software product lines (SPLs) focus on the problem of reuse by providing ways to build software products having commonalities and managing variations within products of the same family. Feature modelling is a well know technique to manage variability and configure products within the SPLs. We have combined the two approaches to formally specify SPLs using Event-B. This will contribute the concept of formalism to SPLs and re-usability to Event-B. Existing feature modelling notations were adapted and extended to include refinement mechanism of Event-B. An Eclipse-based graphical feature modelling tool has been developed as a plug-in to the Rodin platform. We have modelled the "production cell" case-study in Event-B, an industrial metal processing plant, which has previously been specified in a number of formalisms. We have also highlighted future directions based on our experience with this framework so far

Towards Usable End-user Authentication

Authentication is the process of validating the identity of an entity, e.g., a person, a machine, etc.; the entity usually provides a proof of identity in order to be authenticated. When the entity - to be authenticated - is a human, the authentication process is called end-user authentication. Making an end-user authentication usable entails making it easy for a human to obtain, manage, and input the proof of identity in a secure manner. In machine-to-machine authentication, both ends have comparable memory and computational power to securely carry out the authentication process using cryptographic primitives and protocols. On the contrary, as a human has limited memory and computational power, in end-user authentication, cryptography is of little use. Although password based end-user authentication has many well-known security and usability problems, it is the de facto standard. Almost half a century of research effort has produced a multitude of end-user authentication methods more sophisticated than passwords; yet, none has come close to replacing passwords. In this dissertation, taking advantage of the built-in sensing capability of smartphones, we propose an end-user authentication framework for smartphones - called ePet - which does not require any active participation from the user most of the times; thus the proposed framework is highly usable. Using data collected from subjects, we validate a part of the authentication framework for the Android platform. For web authentication, in this dissertation, we propose a novel password creation interface, which helps a user remember a newly created password with more confidence - by allowing her to perform various memory tasks built upon her new password. Declarative and motor memory help the user remember and efficiently input a password. From a within-subjects study we show that declarative memory is sufficient for passwords; motor memory mostly facilitate the input process and thus the memory tasks have been designed to help cement the declarative memory for a newly created password. This dissertation concludes with an evaluation of the increased usability of the proposed interface through a between-subjects study

Panorama - a software maintenance tool

Much of the effort in software maintenance is spent on finding relevant information and on program comprehension. Of the several challenges encountered during this process, some are: a) inadequate documentation, b) the developer doing the maintenance activity may not be the one who actually developed it and may be unfamiliar with the application domain (in addition to the unfamiliar code), c) information overload, and d) the relevant code may be scattered across multiple files of different types making it harder to find. Existing documentation in the form of Javadoc is inadequate in providing a global view of the working of the software. Panorama, a java based Eclipse plug-in, was developed to facilitate maintenance activities by providing mechanisms to document and to view expert knowledge and relevant code in the form of a concern. Some features of Panorama are: a code tracing feature that allows the expert to quickly find (so he can document it) lines of code executed in carrying out a function, a concern management feature that allows the expert to create and organize concern information in a hierarchical manner, a concern visualization and context management feature that helps the maintainer to handle information overload by allowing him to switch between contexts, an enhanced user-interface that helps the maintainer to easily navigate between relevant contexts and codes. Panorama also provides a Javadoc -like documentation of cross-cutting concerns that supplement existing Javadoc documentation to provide comprehensive information about the software. In a case study done to validate the usefulness of our tool, Panorama was used to document the SAVER software (a VB.NET based fairly large GIS software with 26,704 executable lines of code that is being actively used by the Iowa Department of Transportation to analyze automobile crashes over a period of time). SAVER has been undergoing continual bug-fixes and enhancement activities - and preliminary studies indicate that the supplementary documentation provided by Panorama has proven beneficial

Eight grand challenges in socio-environmental systems modeling

Modeling is essential to characterize and explore complex societal and environmental issues in systematic and collaborative ways. Socio-environmental systems (SES) modeling integrates knowledge and perspectives into conceptual and computational tools that explicitly recognize how human decisions affect the environment. Depending on the modeling purpose, many SES modelers also realize that involvement of stakeholders and experts is fundamental to support social learning and decision-making processes for achieving improved environmental and social outcomes. The contribution of this paper lies in identifying and formulating grand challenges that need to be overcome to accelerate the development and adaptation of SES modeling. Eight challenges are delineated: bridging epistemologies across disciplines; multi-dimensional uncertainty assessment and management; scales and scaling issues; combining qualitative and quantitative methods and data; furthering the adoption and impacts of SES modeling on policy; capturing structural changes; representing human dimensions in SES; and leveraging new data types and sources. These challenges limit our ability to effectively use SES modeling to provide the knowledge and information essential for supporting decision making. Whereas some of these challenges are not unique to SES modeling and may be pervasive in other scientific fields, they still act as barriers as well as research opportunities for the SES modeling community. For each challenge, we outline basic steps that can be taken to surmount the underpinning barriers. Thus, the paper identifies priority research areas in SES modeling, chiefly related to progressing modeling products, processes and practices.</jats:p