16,580 research outputs found

    Requirements-driven self-repairing against environmental failures

    Get PDF
    Self-repairing approaches have been proposed to alleviate the runtime requirements satisfaction problem by switching to appropriate alternative solutions according to the feedback monitored. However, little has been done formally on analyzing the relations between specific environmental failures and corresponding repairing decisions, making it a challenge to derive a set of alternative solutions to withstand possible environmental failures at runtime. To address these challenges, we propose a requirements-driven self-repairing approach against environmental failures, which combines both development-time and runtime techniques. At the development phase, in a stepwise manner, we formally analyze the issue of self-repairing against environmental failures with the support of the model checking technique, and then design a sufficient and necessary set of alternative solutions to withstand possible environmental failures. The runtime part is a runtime self-repairing mechanism that monitors the operating environment for unsatisfiable situations, and makes self-repairing decisions among alternative solutions in response to the detected environmental failures

    Requirements-Driven Self-Repairing against Environmental Failures

    Full text link

    Continuous maintenance and the future – Foundations and technological challenges

    Get PDF
    High value and long life products require continuous maintenance throughout their life cycle to achieve required performance with optimum through-life cost. This paper presents foundations and technologies required to offer the maintenance service. Component and system level degradation science, assessment and modelling along with life cycle ‘big data’ analytics are the two most important knowledge and skill base required for the continuous maintenance. Advanced computing and visualisation technologies will improve efficiency of the maintenance and reduce through-life cost of the product. Future of continuous maintenance within the Industry 4.0 context also identifies the role of IoT, standards and cyber security

    Speculative Literature in Modern Society: Octavia Butler and the Tragedy of the Commons

    Get PDF
    What leads to peaceful prosperity and what leads to destructive collapse in any society? While it may seem daunting or overwhelming to dissect the success or collapse of a multi-faceted society, there are lenses and tools through which we are able to do so, such as political theory and speculative dystopian fiction. By using lenses to analyze the society in which we live, we are able to recognize the seeds of both prosperity and destruction in our society that may otherwise be overlooked or ignored. The speculative dystopian fiction of Octavia Butler may be considered as building upon the political theory of the tragedy of the commons. Butler provides her American audience an analysis of the root causes of this tragedy, as well as some possible preventative measures or solutions. We are able to read her novel, The Parable of the Sower, as a warning against ignoring current trends in our society which could lead to our tragedy of the commons. Octavia Butler was an American author of speculative dystopian fiction, and was the first science fiction novelist to be awarded the MacArthur Fellowship in 1955. She was born in California on June 22, 1947 and died in Washington on January 24, 2006. Butler was well-known for critiquing social hierarchies and inequalities as well as for exploring what forms healthy, sustainable communities. Her first novel in her Parable Series, The Parable of the Sower, introduces Butler’s reader to a broken community in a divided society after an environmental apocalypse. Through her protagonist, Lauren Olamina, Butler shows her reader the flaws and failures in society that lead to the community’s collapse as well as how a community can be rebuilt

    Coase and Car Repair: Who Should Be Responsible for Emissions of Vehicles in Use?

    Get PDF
    This paper examines the current assignment of liability for in-use vehicle emissions and suggests some alternative policies that may reduce the cost and increase the effectiveness. The authors first discuss the cost, performance and incentives under current Inspection and Maintenance (I/M) programs, using the recently implemented Arizona "Enhanced I/M" program as an example. These programs were designed to identify and repair vehicles with malfunctioning emission control systems. Since their inception, however, I/M programs have been plagued by transaction costs that have drastically raised the cost of I/M as well as limited its effectiveness. These transaction costs fall into three categories: emission monitoring, repair avoidance, and non-transferability of emission reductions. The authors argue that most of these transaction costs can be attributed to the current assignment of liability for I/M to motorists, and they examine the potential for other liability assignments to reduce transaction costs and improve program efficiency. Among the alternative institutional arrangements discussed are greater imposition of liability on manufacturers, emission repair subsidies, repair liability auctions, and vehicle leasing.

    Toward Biologically-Inspired Self-Healing, Resilient Architectures for Digital Instrumentation and Control Systems and Embedded Devices

    Get PDF
    Digital Instrumentation and Control (I&C) systems in safety-related applications of next generation industrial automation systems require high levels of resilience against different fault classes. One of the more essential concepts for achieving this goal is the notion of resilient and survivable digital I&C systems. In recent years, self-healing concepts based on biological physiology have received attention for the design of robust digital systems. However, many of these approaches have not been architected from the outset with safety in mind, nor have they been targeted for the automation community where a significant need exists. This dissertation presents a new self-healing digital I&C architecture called BioSymPLe, inspired from the way nature responds, defends and heals: the stem cells in the immune system of living organisms, the life cycle of the living cell, and the pathway from Deoxyribonucleic acid (DNA) to protein. The BioSymPLe architecture is integrating biological concepts, fault tolerance techniques, and operational schematics for the international standard IEC 61131-3 to facilitate adoption in the automation industry. BioSymPLe is organized into three hierarchical levels: the local function migration layer from the top side, the critical service layer in the middle, and the global function migration layer from the bottom side. The local layer is used to monitor the correct execution of functions at the cellular level and to activate healing mechanisms at the critical service level. The critical layer is allocating a group of functional B cells which represent the building block that executes the intended functionality of critical application based on the expression for DNA genetic codes stored inside each cell. The global layer uses a concept of embryonic stem cells by differentiating these type of cells to repair the faulty T cells and supervising all repair mechanisms. Finally, two industrial applications have been mapped on the proposed architecture, which are capable of tolerating a significant number of faults (transient, permanent, and hardware common cause failures CCFs) that can stem from environmental disturbances and we believe the nexus of its concepts can positively impact the next generation of critical systems in the automation industry

    Diagnosing faults in autonomous robot plan execution

    Get PDF
    A major requirement for an autonomous robot is the capability to diagnose faults during plan execution in an uncertain environment. Many diagnostic researches concentrate only on hardware failures within an autonomous robot. Taking a different approach, the implementation of a Telerobot Diagnostic System that addresses, in addition to the hardware failures, failures caused by unexpected event changes in the environment or failures due to plan errors, is described. One feature of the system is the utilization of task-plan knowledge and context information to deduce fault symptoms. This forward deduction provides valuable information on past activities and the current expectations of a robotic event, both of which can guide the plan-execution inference process. The inference process adopts a model-based technique to recreate the plan-execution process and to confirm fault-source hypotheses. This technique allows the system to diagnose multiple faults due to either unexpected plan failures or hardware errors. This research initiates a major effort to investigate relationships between hardware faults and plan errors, relationships which were not addressed in the past. The results of this research will provide a clear understanding of how to generate a better task planner for an autonomous robot and how to recover the robot from faults in a critical environment

    Repair Matters

    Get PDF
    Repair has visibly come to the fore in recent academic and policy debates, to the point that ‘repair studies’ is now emerging as a novel focus of research. Through the lens of repair, scholars with diverse backgrounds are coming together to rethink our relationships with the human-made matters, tools and objects that are the material mesh in which organisational life takes place as a political question. This special issue is interested to map the ways that repair can contribute to organisational models alternative to those centered around growth. In order to explore the politics of repair in the context of organization studies, the papers gathered here investigate issues such as: repair as a specific kind of care and socially reproductive labour; repair as a direct intervention into the cornerstones of capitalist economy, such as exchange versus use value, division of work and property relations; repair of infrastructures and their relation with the broader environment; and finally repair as the reflective practice of fixing the organizational systems and institutional habits in which we dwell. What emerges from the diversity of experiences surveyed in this issue is that repair manifests itself as both a regime of practice and counter-conduct that demand an active and persistent engagement of practitioners with the systemic contradictions and power struggles shaping our material world

    Des indicateurs clés de performances pour accroître la résilience des réseaux sur trois étapes

    Get PDF
    International audienceWater distribution networks (WDNs) are critical infrastructures that should face multiple and continuous changes and adverse operative conditions (due to abnormal events) that alter their normal service provision. The main objective of a WDN is to deliver the required amount of water to the customer under a certain threshold of the desired pressure and quality. Therefore, ensuring resilience and safety of WDSs are big concerns for water utilities. Several resilience key performance indicators have been suggested to quantify and assessing WDN resilience. Regarding the objectives of resilience, water utility managers require modelling tools to be able to predict how the WDN will perform during disruptive events and understand how the system can better absorb them. Tools such as: demand-driven modelling (DDM) for sufficient pressure conditions, and pressure-driven modelling (PDM) for insufficient pressure conditions, aid to simulate WDNs performance under adverse operative conditions. This work attempts to evaluate the network resilience. The proposed approach is based on an event-driven methodology and there is considered the time when the event occurs, when it evolves, and the sequence of the events. It should be carefully selected the type of the approach (PDM or DDM) used for the hydraulic model, as well as the system performance state and the uses of resilience power-based indicators. The results are promising in order to provide to water managers with a great depth of information and support better preparedness for WDNs
    • …
    corecore