88 research outputs found

    Safety Verification for Autonomous Ships

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    Autonomous and unmanned ships are approaching reality. One of several unsolved challenges related to these systems is how to perform safety verification. Although this challenge represents a many-faceted problem, which must be addressed at several levels, it seems likely that simulatorbased testing of high-level computer control systems will be an important technique. In the field of reliability verification and testing, design verification refers to the process of verifying that specified functions are satisfied over the life of a system. A basic requirement for any autonomous ship is that it has to be safe. In this paper, we propose to use the Systems-Theoretic Process Analysis (STPA) to (i) derive potential loss scenarios for autonomous ships and safety requirements to prevent them from occurring, and (ii) to develop a safety verification program, including test cases, intended to verify safety. Loss scenarios and associated safety requirements are derived using STPA. To derive a safety verification program, these unsafe scenarios and safety requirements are used to identify key variables, verification objectives, acceptance criteria and a set of suitable verification activities related to each scenario. The paper describes the proposed methodology and demonstrates it in a case study. Test cases for simulator-based testing and practical sea-trials are derived for autonomous ships. The case study shows that the proposed method is feasible as a way of generating a holistic safety verification program for autonomous ships

    Human factor influences on supervisory control of remotely operated and autonomous vessels

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    Autonomous ships require remote supervision from a human operator to ensure safety. However, there are knowledge gaps concerning human factor influences on remote supervisory control. We investigate the influence of five factors on remote supervisory control during simulated intervention scenarios: (i) Skillset, represented by gamers and navigators; (ii) Monitoring Time, represented by either 5 or 30 min of passive monitoring; (iii) Number of Vessels, represented by either one or three vessels; (iv) Available Time, represented by 20- or 60-s critical time windows; (v) Decision Support System (DSS), represented by availability of a DSS. The experiment was a randomized factorial design where participants (n = 32) completed two interventions: first a handover (automation detects a critical event and hands over control) and then a takeover (operator detects a critical event and takes over control). We observed: (i) gamers and navigators both demonstrated transferrable skillsets, but neither group excelled over the other; (ii) monitoring time affected boredom, but this translated to minor performance effects. Moreover, performance was reduced under conditions of (iii) supervising three vessels, (iv) low time availability, and (v) unavailable DSS. These outcomes contribute to the empirical basis for assessing maritime human factors in remotely controlled and autonomous ship design.publishedVersio

    Maintenance strategies for deep sea offshore wind turbines

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    Purpose – The objective of this paper is to outline a framework that guides the development of sound maintenance strategies and policies for deep‐sea offshore wind turbines. Design/methodology/approach – An important challenge with offshore wind energy production is to reduce the high operation and maintenance costs. To decrease complexity, and structure the maintenance strategy developing process, systems engineering principles are used. Findings – The framework facilitates integration of fragmented but valuable information from different disciplines in the development of sound maintenance strategies. In addition, the framework may be used to identify knowledge gaps, and areas for further research. Research limitations/implications – The paper refers to research on deep‐sea offshore wind turbines, which is in its infancy, with a limited amount of data yet available for verification and validation. Deep‐sea offshore installations are not commercialized, and few pilot installations have been installed. Originality/value – The design of the offshore wind turbines determines operation and maintenance features. Reducing operation and maintenance costs is necessary to make deep‐sea offshore wind projects viable in the first place. The framework contributes to the complicated development of maintenance strategies for a system not yet realized

    Sustainable Fishing Fleet; a Systems Engineering Approach

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    Many fisheries have significant challenges related to sustainable development, such as overexploitation and overcapacity in the fishing fleet. Overcapacity leads to increased pressure on fish resources, reduced profitability, and environmental problems such as greenhouse gas (GHG) emissions and acidification fromfuel consumption. Sustainable management of the fish resources is an important objective in Norway, but overcapacity is a problem in several Norwegian fleet segments. Important issues in this respect are whether the traditional management models are able to deal with the capacity development, and whether the role of technology as a relevant discipline in fisheries management is underestimated. The objective of this work has been to integrate a technological perspective into fisheries management in order to improve sustainability in the fishing fleet. The thesis work has been limited to the Norwegian fisheries in Norwegian territorialwaters. Since the main problems addressed in this thesis are sustainability and overcapacity, the system boundaries are limited to the fishing fleet. This means that the marine ecosystem in where the fishing vessels are interacting, is outside the thesis’ boundaries. The main contributions of this thesis are: • Development of a methodological framework that structures fisheries management decision-making, with main emphasis on improved sustainability in the fishing fleet. • Clarification of the concept of sustainability in the Norwegian fishing fleet. • Classification of attributes characterizing sustainability, and a performance evaluation of the different vessel groups in the cod-fishing fleet. • Comparison of two cod-production systems, with focus on sustainability. • Suggestions for how fisheries management can evaluate sustainability on a regular basis. • Improved foundation for further research about sustainability in the fisheries. A lot of literature is collected and synthesized. The framework developed is based on the systems engineering process. The nature of sustainability requires a systems perspective. There are different system analysis methods, but from a technological perspective, dealing with multidisciplinary tasks, systems engineering has been selected as the most feasible process. It has a strong focus on stakeholder needs and requirements, and it facilitates frequent evaluations of sustainability, which is important in order to assess management efficiency and goal achievement. Problems regarding sustainability in the fisheries are not only caused by technological development, but have organizational challenges as well. However, in this thesis the focus is within the technological perspective. Systems engineering is not applied as an attempt to change the structure of fisheries management, but as means of suggesting a decision-making process that improves sustainability in the fishing fleet. Fisheries management involves decision-making in situations often characterized by high risks and uncertainties, and it may be difficult to predict the outcomes of the decisions, for example, regarding sustainability in the fishing fleet. A number of tools that are available to support decision-making have been discussed and used in the thesis, such as cost-benefit analysis, risk acceptance criteria, life cycle cost (LCC), the Analytic Hierarchy Process (AHP), and Quality Function Deployment (QFD). Nevertheless, these tools do not provide “correct” answers; they have limitations, they are based on a number of assumptions, and their uses are based on scientific knowledge as well as value judgments involving political, strategic, and ethical issues. This means that these methods leave the decision-makers to apply decision processes outside the practical applications of the analyses, to which the framework offers guiding principles and structure. The main outcome of using systems engineering principles in fisheries management, is that the framework offers a broader analytical perspective to fisheries management and sustainability, which acknowledge that sustainability cannot be distinguished fromthe context. Today, most input to fisheries management come from biology and economy, such as stock assessments and profitability analyses. In systems engineering, information from different scientific disciplines, for example, biology, social sciences, economy, and technology, are necessary input to the analyses and decision processes, because fisheriesmanagement is much more than bio-economics. Application of the systems engineering process in fisheries management, and the inclusion of technology, introduce new perspectives, new disciplines, and new stakeholders into the decision-making process in the fisheries. Based on the framework developed in the thesis, the sustainability performance of the cod-fishing fleet has been evaluated. Sustainability in the fishing fleet may be characterized by seven attributes; accident risk, employment, profitability, quality, catch capacity, bycatch/selection, andGHGemissions/acidification. Indicators have been identified in order to measure the system performance within the attributes. The evaluation shows that there are differences in the performance of the vessel groups. These differences pose a major challenge to fisheries management in their decision-making regarding sustainability in the fleet. The smallest vessels have the lowest fuel consumption (kg fuel/kg fish), but they have a very high accident risk (FAR). The evaluation of cod fishing vs. cod farming shows that the potential growth in the cod farming industry may cause changes in the management system of the cod fisheries, such as a possible shift from the IVQ-systemof today to an ITQ-system. The Norwegian fisheries management lacks frequent evaluations of its policies, and the information and data available about the fisheries are fragmented. Sustainability should be evaluated on a regular basis by use of performance indicators to determine if sustainability increases or decreases. For simplicity, the indicators could be aggregated into a sustainability index showing the overall system performance. Aggregation implies simplification and weighting of the indicators, which means that such an index should be used with care. Sustainability implies a long term perspective when taking decisions, because future generations will be affected. The performance evaluations can give indications of trends, which means that the results can be used to predict consequences in the future, based on the current development.Paper I, II, III, IV and VI are reprinted with kind permission of Elsevier, sciencedirect.co

    Systems engineering principles in fisheries management

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    Fisheries management receives valuable, but often fragmented information from academic disciplines such as biology, economics, and social sciences. A multi-disciplinary perspective seems to be necessary if the fisheries are to become sustainable. Globally, overcapacity is considered as the most serious threat to sustainable fisheries, which indicates the need for a stronger integration of technological aspects into fisheries management. This paper discusses application of systems engineering principles and integration of technology into fisheries management. The systems engineering process facilitates implementation of multi-disciplinary information from researchers to fisheries managers in the decision-making towards sustainable fisheries, but may also be used to overcome multi-disciplinary obstacles among scientists. The article concludes that use of systems engineering principles may become a valuable contribution to fisheries management because of increased transparency and reduced risk associated with the decision-making process.Fisheries management Sustainable fisheries Technology

    Common patterns in aggregated accident analysis charts from human fatigue-related groundings and collisions at sea

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    Research has shown that there are potentially disastrous outcomes of human fatigue at sea. The conditions in which the seafarers have to operate are becoming more and more demanding. The study in this article attempts to aggregate accident charts derived from in-depth studies of human fatigue-related accidents to determine common patterns of interlinked fatigue factors. The accidents are analyzed by means of the Cognitive Reliability and Error Analysis Method (CREAM), which in the article has been modified for maritime accidents. The main fatigue factors identified are ‘shift work’, ‘irregular working hours’, ‘inadequate task allocation’, and ‘excessive demands’. The study reveals several differences between ship collision and grounding accidents and their corresponding fatigue factors. Human fatigue-related collision accidents are characterized by wrong/badly timed decisions, misconceptions, and poor communication between the vessels. Right before the collision the crew is often panicking and mistakes are easily made. In human fatigue-related groundings, the conditions are often monotonous and the navigating officer has either overlooked the upcoming seabed or simply fallen asleep. Safety climate issues are also identified as important contributors to human fatigue.publishedVersio

    System evaluation of sustainability in the Norwegian cod-fisheries

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    Overcapacity in the fishing fleets is considered as the most serious threat to sustainable fisheries. More effective fishing vessels and catching gear contribute to increased catch capacity. Increased catch capacity causes environmental problems such as overexploitation and calls for larger quotas. The problem of overcapacity indicates the need for a stronger integration of technological aspects into fisheries management. This article assesses the differences in sustainability between the Norwegian ocean and coastal fishing fleets in the cod fisheries, by using systems engineering methods. Attributes of sustainability in the Norwegian cod fishing fleets are investigated, as well as acceptance criteria and performance indicators. The results show that there are huge differences in the performance between the vessel groups, and that the results of an evaluation of sustainability in the fishing fleets are dependent on which attributes are explored. Thus, the discussion may contribute to a better decision basis and improved sustainability in fisheries management.Sustainable fisheries management Performance indicators Systems engineering
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