25 research outputs found

    A proposed framework for managing environmental causes and consequences of ocean traffic and ports

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    Paper presented at European Decision Sciences Institute (ED2016), 7th Annual Conference, 24th to 27th May 2016, Helsinki. Abstract The cumulative and in-combination effects of ocean shipping and port operations need addressing via a detailed, rigorous and holistic framework of risk assessment and risk management. This aims to protect the natural system while at the same time obtaining societal benefits from the seas. This paper proposes a conceptual framework that integrates both an ISO industry standard risk assessment and management framework (Bow-tie analysis) and the DAPSI(W)R(M) analysis supported by the ten-tenets criteria to provide guidance for all stakeholders, including industry and government, to address these issues. Water pollution stemming from maritime logistics and SCM are used to illustrate this framework

    A hybrid and integrated approach to evaluate and prevent disasters

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    Mutual recognition of national military airworthiness authorities: A streamlined assessment process

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    The Air and Space Interoperability Council (ASIC) has adopted the European Defence Agency (EDA) process for interregulatory military airworthiness authority recognition. However, there are gaps in the application of this process to nations outside of the European Union. This paper proposes a model that can effectively map diverse technical airworthiness regulatory frameworks. This model, referred to as the Product-Behaviour-Process (PBP) Bow-Tie model, provides the systematic structure needed to represent and compare regulatory frameworks. The PBP Bow-Tie model identifies key points of difference that need to be addressed, during inter-agency recognition between the two regulatory authorities. With the intention to adopt global use of the EDA process, the proposed PBP Bow-Tie model can be used as a basis for the successful recognition of regulatory frameworks outside of the European Union. Iris plots produced from the implementation of this model are presented, and proposed as a suitable means of illustrating the outcome of an assessment, and of supporting the comparisons of results. A comparative analysis of the Australian Defence Force and New Zealand Defence Force airworthiness regulatory frameworks is used as a case study. The case study clearly illustrates the effectiveness of the model in discerning regulatory framework differences; moreover, it has offered an opportunity to explore the limitations of the Iris plot

    Strategic Analysis of Transit Service Quality Using Fuzzy AHP Methodology

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    Customer satisfaction analyses are deeply based on customers’ judgments and as consequence, they can be characterized by a certain degree of uncertainty generally ascribed to coexistence of three relevant aspects: vagueness, imprecision and subjectivity. In the present paper, a methodology able to handle such uncertainty, based on the ServQual discrepancy paradigm and that uses in combined manner the AHP method and the Fuzzy Sets Theory is proposed in order to overcome limitations of the traditional service evaluation approaches. Subsequently, by considering the Italian public transit service sector, a service quality analysis is conducted and the overall transit service quality structure is described. Finally, by using the developed methodology, the evaluation of customer satisfaction for the public urban transit service provided in the city of Palermo (Italy) is performed, and the prioritizing of its critical to quality service attributes is carried out. The obtained results show that only few service attributes play an important role in performing a quality transit service

    A fuzzy-based holistic approach for supply chain risk assessment and aggregation considering risk interdependencies

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    ProducciĂłn CientĂ­ficaSupply chain risk management requires dealing with uncertainty, interrelations, and subjectivity inherent in the risk assessment process. This paper proposes a holistic approach for risk management that considers the impact on multiple performance objectives, the relation between risk agents, and the risk event interdependencies. An aggregated risk score is proposed to capture the cascading effects of common risk triggers and quantify the aggregated score by risk agent and objective. The approach also uses fuzzy logic to allow for the treatment of vague and ambiguity data as input parameters to the model from different domains and scales, according to knowledge and criteria nature. The integration of the balanced scorecard tool improves the analysis and prioritization of mitigation strategies in decision-making, both by risk agent and by strategic objective. A case study of a telecommunication company is presented to illustrate the applicability of the proposed approach

    Safety Considerations of Hydrogen Application in Shipping in Comparison to LNG

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    Shipping accounts for about 3% of global CO2 emissions. In order to achieve the target set by the Paris Agreement, IMO introduced their GHG strategy. This strategy envisages 50% emission reduction from international shipping by 2050, compared with 2008. This target cannot be fulfilled if conventional fuels are used. Amongst others, hydrogen is considered to be one of the strong candidates as a zero-emissions fuel. Yet, concerns around the safety of its storage and usage have been formulated and need to be addressed. Safety, in this article, is defined as the control of recognized hazards to achieve an acceptable level of risk. This article aims to propose a new way of comparing two systems with regard to their safety. Since safety cannot be directly measured, fuzzy set theory is used to compare linguistic terms such as safer. This method is proposed to be used during the alternative design approach. This approach is necessary for deviations from IMO rules, for example, when hydrogen should be used in shipping. Additionally, the properties of hydrogen that can pose a hazard, such as its wide flammability range, are identified

    Disjunctively incomplete information in relational databases: modeling and related issues

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    In this dissertation, the issues related to the information incompleteness in relational databases are explored. In general, this dissertation can be divided into two parts. The first part extends the relational natural join operator and the update operations of insertion and deletion to I-tables, an extended relational model representing inclusively indefinite and maybe information, in a semantically correct manner. Rudimentary or naive algorithms for computing natural joins on I-tables require an exponential number of pair-up operations and block accesses proportional to the size of I-tables due to the combinatorial nature of natural joins on I-tables. Thus, the problem becomes intractable for large I-tables. An algorithm for computing natural joins under the extended model which reduces the number of pair-up operations to a linear order of complexity in general and in the worst case to a polynomial order of complexity with respect to the size of I-tables is proposed in this dissertation. In addition, this algorithm also reduces the number of block accesses to a linear order of complexity with respect to the size of I-tables;The second part is related to the modeling aspect of incomplete databases. An extended relational model, called E-table, is proposed. E-table is capable of representing exclusively disjunctive information. That is, disjunctions of the form P[subscript]1\mid P[subscript]2\mid·s\mid P[subscript]n, where ǁ denotes a generalized logical exclusive or indicating that exactly one of the P[subscript]i\u27s can be true. The information content of an E-table is precisely defined and relational operators of selection, projection, difference, union, intersection, and cartisian product are extended to E-tables in a semantically correct manner. Conditions under which redundancies could arise due to the presence of exclusively disjunctive information are characterized and the procedure for resolving redundancies is presented;Finally, this dissertation is concluded with discussions on the directions for further research in the area of incomplete information modeling. In particular, a sketch of a relational model, IE-table (Inclusive and Exclusive table), for representing both inclusively and exclusively disjunctive information is provided
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