843,363 research outputs found

    The Case for Formal Methods in Standards

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    It is argued that applying formal methods to standards making would result in more accurate, more understandable, and more useful standards. The main benefit seen in using formal methods in a standard's development and expression is improving the standard's quality. In the early stages of standards development, formal methods can result in considerable clarification during the development and expression of the underlying conceptual model for a standard or family of related standards. They can also define precisely the relation among the components of both the standard being developed and other standards. Later in the development process, formal methods can improve a standard's quality during its use by letting it be expressed clearly, unambiguously, and concisely in a way that natural language does not allow. Finally, formal methods can aid standards development at the maintenance stage, for example, by allowing the adequacy of a proposed change to be proved. Guidelines for applying formal methods in the standardization process are provided

    Joint use of static and dynamic software verification techniques: a cross-domain view in safety critical system industries

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    International audienceHow different are the approaches to combining formal methods (FM) and testing in the safety standards of the automotive, aeronautic, nuclear, process, railway and space industries? This is the question addressed in this paper by a cross-domain group of experts involved in the revision committees of ISO 26262, DO-178C, IEC 60880, IEC 61508, EN 50128 and ECSS-Q-ST-8OC. First we review some commonalities and differences regarding application of formal methods in theaforementioned standards. Are they mandatory or recommended only? What kind of properties are they advised to be applied to? What is specified in the different standards regarding coverage (both functional and structural) if testing and formal methods are used jointly?We also account for the return on experience of the group members in the six industrial domains regarding state of the art practice of joint use of formal methods and testing. Where did formal methods actually prove to outperform testing? Then we discuss verification coverage, and more specifically the role of structural coverage. Does structural coverage play the same role in all the standards? Is it specific to testing and irrelevant for formal methods? What verification terminationcriteria is applicable in case FM-test mix? We conclude on some prospective views on how software safety standards may evolve to maximize the benefits of joint use of dynamic (testing) and static (FM) verification methods

    Requirements analysis of the VoD application using the tools in TRADE

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    This report contains a specification of requirements for a video-on-demand (VoD) application developed at Belgacom, used as a trial application in the 2RARE project. The specification contains three parts: an informal specification in natural language; a semiformal specification consisting of a number of diagrams intended to illustrate the informal specification; and a formal specification that makes the requiremants on the desired software system precise. The informal specification is structured in such a way that it resembles official specification documents conforming to standards such as that of IEEE or ESA. The semiformal specification uses some of the tools in from a requirements engineering toolkit called TRADE (Toolkit for Requirements And Design Engineering). The purpose of TRADE is to combine the best ideas in current structured and object-oriented analysis and design methods within a traditional systems engineering framework. In the case of the VoD system, the systems engineering framework is useful because it provides techniques for allocation and flowdown of system functions to components. TRADE consists of semiformal techniques taken from structured and object-oriented analysis as well as a formal specification langyage, which provides constructs that correspond to the semiformal constructs. The formal specification used in TRADE is LCM (Language for Conceptual Modeling), which is a syntactically sugared version of order-sorted dynamic logic with equality. The purpose of this report is to illustrate and validate the TRADE/LCM approach in the specification of distributed, communication-intensive systems

    Managing People In A Lean Environment: The Power Of Informal Controls And Effective Management Of Company Culture

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    This short case at a high tech company in the Midwest, illustrates some important principles for managing people focusing more on informal, rather than formal controls.  Lean Thinking advocates reducing waste, and continuously improving (Womack & Jones, 2003).  When a company shifts paradigms from traditional management to Lean management, the culture of the company transforms in many ways.  Traditional, formal methods of controlling employee behavior often involve a lot of non-value-add labor and cost, at the same time, they are not effective.  They are seemingly based on the attitude that employees are unprofessional, cannot develop internalized standards of behavior or understand the “big picture” of why it is in their own best interests to maintain high standards.  Analysis of this incident is useful for students of Lean management, in helping them see the power of informal controls embedded in the company culture

    The engineering of generic requirements for failure management

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    We consider the failure detection and management function for engine control systems as an application domain where product line engineering is indicated. The need to develop a generic requirement set - for subsequent system instantiation - is complicated by the addition of the high levels of verification demanded by this safety-critical domain, subject to avionics industry standards. We present our case study experience in this area as a candidate methodology for the engineering, validation and verification of generic requirements using domain engineering and Formal Methods techniques and tools. For a defined class of systems, the case study produces a generic requirement set in UML and an example instantiation in tabular form. Domain analysis and engineering produce a model which is integrated with the formal specification/ verification method B by the use of our UML-B profile. The formal verification both of the generic requirement set, and of a simple system instance, is demonstrated using our U2B and ProB tools. This work is a demonstrator for a tool-supported method which will be an output of EU project RODIN. The method, based in the dominant UML standard, will exploit formal verification technology largely as a "black box" for this novel combination of product line, failure management and safety-critical engineering

    Introduction: absorbing the four methodological disruptions in democratization research?

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    This article introduces the special issue on methodological trends in democratization research by taking stock of the overall development of methods practices and situating the findings of the individual article contributions within the broader developments. As has the broader discipline, democratization research has experienced four methodological "disruptions" over the past 60 years: the behavioural revolution of statistical methodology; the introduction of formal theory; the sophistication of qualitative, set-theoretic and multi-method research; and the increasing use of experimental methods. Surveying the methods practices in the past quarter century, we find that quantitative and multi-method research have been growth areas in recent years, but that the bulk of research is still done in comparative or single case studies. Formal theory as well as set-theoretic methods have gained a foothold in the field, but it is still a small one. In sum, democratization research is, methodologically speaking, still rather traditional. Moreover, the individual contributions to this special issue show that much of the empirical literature underutilizes the best available advice about how to develop and test theory, including standards on causal inference, case-selection, and generalization. We conclude with a plea for more transparency, humility, and collaboration within and across methodological traditions

    Virtual patients design and its effect on clinical reasoning and student experience : a protocol for a randomised factorial multi-centre study

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    Background Virtual Patients (VPs) are web-based representations of realistic clinical cases. They are proposed as being an optimal method for teaching clinical reasoning skills. International standards exist which define precisely what constitutes a VP. There are multiple design possibilities for VPs, however there is little formal evidence to support individual design features. The purpose of this trial is to explore the effect of two different potentially important design features on clinical reasoning skills and the student experience. These are the branching case pathways (present or absent) and structured clinical reasoning feedback (present or absent). Methods/Design This is a multi-centre randomised 2x2 factorial design study evaluating two independent variables of VP design, branching (present or absent), and structured clinical reasoning feedback (present or absent).The study will be carried out in medical student volunteers in one year group from three university medical schools in the United Kingdom, Warwick, Keele and Birmingham. There are four core musculoskeletal topics. Each case can be designed in four different ways, equating to 16 VPs required for the research. Students will be randomised to four groups, completing the four VP topics in the same order, but with each group exposed to a different VP design sequentially. All students will be exposed to the four designs. Primary outcomes are performance for each case design in a standardized fifteen item clinical reasoning assessment, integrated into each VP, which is identical for each topic. Additionally a 15-item self-reported evaluation is completed for each VP, based on a widely used EViP tool. Student patterns of use of the VPs will be recorded. In one centre, formative clinical and examination performance will be recorded, along with a self reported pre and post-intervention reasoning score, the DTI. Our power calculations indicate a sample size of 112 is required for both primary outcomes

    A Conceptual Architecture for Enabling Future Self-Adaptive Service Systems

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    Dynamic integration methods for unknown data sources and services at system design time are currently primarily driven by technological standards. Hence, little emphasis is being placed on integration methods. However, the combination of heterogeneous data sources and services offered by devices across domains is hard to standardize. In this paper, we will shed light on the interplay of self-adaptive system architectures as well as bottom-up, incremental integration methods relying on formal knowledge bases. An incremental integration method has direct influences on both the system architecture itself and the way these systems are engineered and operated during design and runtime. Our findings are evaluated in the context of a case study that uses an adapted bus architecture including two tool prototypes. In addition, we illustrate conceptually how control loops such as MAPE-K can be enriched with machine-readable integration knowledge

    Sustainable deployment of environmental management systems for higher education institutions:challenges and limitations

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    Higher education institutions (HEIs) face unique barriers to implementation of environmental management systems (EMSs) compared to the private sector, where formal EMS approaches such as ISO 14001 are widely used. HEIs across the world have tended to adopt structured EMSs through less formal methods or apply bespoke approaches based on institutional drivers for implementation. This chapter explores organizational factors specific to HEIs that impact on their ability to implement and sustain formal EMS approaches. An in-depth review was undertaken examining key organization barriers to EMS adoption, and organizational factors specific to HEIs that can affect the successful implementation and sustainability of EMS approaches. The study finds that considerations of the key actors, existing organizational structures, governance and leadership, and resistance to change are important areas to consider in the implementation of an EMS within an HEI. UK HEIs are used as a case study to examine the relationship between EMS uptake and performance, and identify trends toward the adoption of various types of systems. We find that a trend toward the adoption of more formalized EMS approaches among UK HEIs contradicts the suggestion from the literature that less-formal approaches may be more suitable. The study challenges the assumption that formal approaches to environmental management such as ISO 14001 and Eco-Management and Audit Scheme (EMAS) provide the gold standard EMS, suggesting that alternative standards may be more suitable in the context of the unique organizational structures and key barriers to EMS implementation faced by HEIs
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