8 research outputs found

    STPA Based Approach for a Resilience Assessment at an Early Design Stage of a Cruise Ship

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    Several definitions and approaches have been proposed to study resilience in different fields like materials, ecology, psychology and infrastructures. A general definition, applicable also to human-made or engineered systems, describes resilience as the ability to maintain capability in case of disruption. Thanks to its systemic, top-down approach, STAMP (System-Theoretic Accident Model and Processes) has been already identified in literature as a very effective and \u201cconductive\u201d reference when reasoning about the possible need of resilience of a complex system. The STAMP-based tool named STPA (System Theoretic Process Analysis) establishes the following steps: identify system accidents, hazards; draw functional control structure; identify unsafe control actions (UCAs); identify accident scenarios; formulate decisions and recommendations. It focuses on what actually is in the hands of the system designer and operator i.e. the possibility to take action on hazards that can be eliminated or controlled. In this paper an approach to design resilience into a cruise vessel will be proposed. An application case will be developed considering the specific hazard of dead ship condition i.e. of energy black-out on board. In case of navigation close to the shore and in heavy weather condition, this situation can rapidly evolve into a loss. The ship energy production and delivery system, both for the propulsion and for the hotel services, will be considered. Running the procedure up to the level of UCAs enables the identification of the possible disruptive events capable to degrade the operational performance of the system. Starting from this point, suggestions will be discussed for a selected UCA, able to prevent or mitigate it. A metric for ship resilience will be proposed as well with the aim to allow comparisons among different design solutions

    A novel "resilience viewpoint" to aid in engineering resilience in systems of systems (SoS)

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    Designing evolutionary systems to meet stakeholder expectations on safety, reliability and overall resilience is of great importance in an age of interconnectivity and high dependency systems. With incidents and disruptions becoming more frequent in recent years, the requirement for systems to demonstrate high levels of resilience given the economic, political and temporal dimensions of complexity, resilience is of great significance today. Systemic resilience is of high importance at the global level. Therefore, the role of the system engineer and architect is becoming more demanding due to the need to consider requirements from a broader range of stakeholders and to implement them into early conceptual designs. The early modeling process of all systems is common ground for most engineering projects, creating an architecture to both understand a system and to design future iterations by applying model-based processes has become the norm. With the concept of systems-ofsystems (SoS) becoming common language across multiple engineering domains, model-based systems engineering techniques are evolving hand-in-hand to provide a paradigm to better analyse current and future SoS. The intrinsic characteristics of the constituent systems that make up the SoS make the challenge of designing and maintaining the reliability and resilience of a systems extremely difficult. This paper proposes a novel viewpoint, within an architecture framework (based around DoDAF, MoDAF and UPDM) to aid systems architects explore and design resilient SoS. This is known as the Resilience Viewpoint. Much of the research in the area is focussed on critical infrastructure (CI), looking at telecommunication networks, electric grid, supply networks etc, and little has been done on a generalizable tool for SoS architecture analysis, especially using existing modeling languages. Here, the application of the ‘Resilience Viewpoint’ is demonstrated using a case study from an integrated water supply system of systems, to portray its potential analytical capabilities

    The systemic and global dimension of business resilience in a socio-technical perspective

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    This paper proposes to augment the concept of a business resilience improving process by enlarging such a process with a dimension of external action that addresses the vaster frame of systemic resilience of our societies. To this aim, I propose to widen the concept of socio-technical system (STS) to human societies, based on the idea that the development and survival of human societies has necessary social and technical factors. I also propose a concept of resilience in terms of dealing with failures of STS. Two particular cases of very large failure avoidance are considered: nuclear war and civilizational collapse, and I propose that such cases should be present in the referred dimension of external action of any business resilience program. Because the action of public governments and their cooperation is crucial for advancing global systemic resilience, I suggest that businesses should analyze and model the decisions of governments in a wider context of naturally occurring cooperating and conflicting human groups.I would like to thank the two anonymous reviewers for criticisms that allowed me to sharpen the generalized concept of socio-technical system and to fuse a general concept of global resilience with business resilience. This paper was financially supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT-Fundacao para a Ciencia e Tecnologia within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio

    Analysis of Resilience Situations for Complex Engineered Systems – the Resilience Holon

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    Improving the resilience of complex engineered and engineering systems (CES) includes planning for complex resilience situations, in which there may be multiple threats, interactions, and disruptions. One challenge in the modeling of CES is the identification of how interactions in a complex situation occur and their combined influence on CES resilience. This article presents a resilience holon that can be used to analyze complex resilience situations. It is made up of 24 elements (defining types of resilience, threats, interactions, and disruptions), which have varying importance to specific situations. Holons can be linked together hierarchically or in a network. An application of the resilience holon to a documented real-world resilience situation, widespread flooding in a city, illustrates its use. Pathways taken by threats and disruptions, as the flood effects cascaded through the city, are shown as connections between holons. The resilience holon could be used to decompose diverse resilience situations involving CES, to identify where critical vulnerability points are and how the whole resilience situation could be improved. The visual nature of the resilience holon could be used in an interactive way, allowing stakeholders to better understand the full resilience picture of CES that they use or operate

    A holistic risk-oriented framework for port infrastructure adaption to climate change

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    This research is the first attempt in developing a broad-based qualitative tool for assessing climate risk in ports and building resilience. In order to demonstrate the applicability of the conceptual tool, the new Durban Dig-Out Port (DDOP) under development in the City of Durban (South Africa) is used for case study. Central to this research is the building of widespread industry recognition of the need to factor climate change into decision making at early stages of port development. The recent significant shift toward supply chain management and customer orientation practices calls for the need to assess the effectiveness of port services in a broader context well beyond port limits. This is also reinforced by the gradual shift in the definition of port infrastructure from physical assets to a complex interactive system (which encompasses notions of soft concepts), forming part of a broader logistic solution covering larger geographical spans. Given their vulnerable locations on coasts that are susceptible to climate variations, seaports face serious threats as a result of climate change. Unfortunately, the complex and uncertain nature of port climate risks makes traditional probabilistic risk management tools inappropriate. Ports require a unique and broad forward-looking management approach to climate change based on logistic network resilience rather than infrastructure resistance

    Building inclusive resilience: Exploring justice and social equity in urban resilience planning

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    This thesis explores the process and politics of planning for urban resilience with an eye to issues of social equity and justice. Resilience approaches to urban planning have experienced a rise in popularity in recent years, thanks in part to high-profile global campaigns like “100 Resilient Cities – Pioneered by The Rockefeller Foundation” (100RC). Several critics, however, have cautioned that the concept of resilience is inherently conservative and negligent to social justice. The goal of this mixed-methods thesis is to empirically test the common theoretical hypothesis that resilience approaches neglect justice by exploring how issues of resilience and justice coalesce or conflict in in-situ instances of resilience planning. Two manuscripts comprise this thesis. The first is a global analysis of City Resilience Strategies produced under the 100RC program, intended to draw broader conclusions about how social equity and justice are prioritized (or not) in written resilience plans. The second is a case study which examines how one participating 100RC city (Toronto, Canada) has attempted to be procedurally just and inclusive in its resilience planning process. In sum, this thesis evaluates both the written products and deliberative processes of planning for resilience. Overall, this research concludes that resilience planning is not inherently at odds with goals of social equity and justice, but that city planners must pay keen attention to issues of redistribution, recognition, and participation during both strategy development and implementation if they hope to advance resilience and justice simultaneously. The thesis highlights a number of tools and recommendations that can be used by local governments and globally networked urban experiments alike to advance equity in their resilience building efforts. The findings of this research can help to inform more inclusive and equitable planning practices for more resilient and sustainable cities

    Integrated production of algal biomass

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    Applied research is increasingly defined within a context of sustainability and ecological modernisation. Within this remit, recent developments in algal biotechnology are considered to hold particular promise in integrating aspects of bioremediation and bioproduction. However, there are still a number of engineering and biological bottlenecks related to large scale production of algae; including requirements to reduce both capital expenditure (CAPEX) and operational expenditure (OPEX). One potential avenue to reduce these costs is via feedstock substitution and resource sharing; often described as industrial symbiosis. Such an approach has the benefit of providing both environmental and economic benefits as part of an ‘eco-biorefinery’. This thesis set out to investigate and address how best to approach some of the cost related bottlenecks within the algal industry, through a process of industrial integration and novel system design. The doctorate focussed on applications within a Northern European context and was split into four research topics. The first and second parts identified a suitable algal strain and were followed by the characterisation of its growth on wastewater; with the findings showing Chlorella sorokiniana (UTEX1230) capable of robust growth and rapid inorganic nutrient removal. The third part detailed the design, construction and validation of a lower cost and fully scalable modular airlift (ALR) photobioreactor, suitable amongst other applications for use within wastewater treatment. This work concluded with a pilot scale deployment of a 50 L ALR system. The fourth research section detailed the costs of ALR construction and operation at a wastewater treatment works, with a particular focus on the benefits that can be derived by industrial symbiosis. The thesis concludes with an appraisal of the ALR design and considers the potential for the technology, particularly within a wastewater treatment role. A final consideration is given to the practicalities of developing the algal industry within the UK in the short to medium term

    Toward a Resilience Framework for Sustainable Engineered Systems

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