A novel method for safety analysis of Cyber-Physical Systems - Application to a ship exhaust gas scrubber system

Cyber-Physical Systems (CPSs) represent a systems category developed and promoted in the maritime industry to automate functions and system operations. In this study, a novel Combinatorial Approach for Safety Analysis is presented, which addresses the traditional safety methods’ limitations by integrating System Theoretic Process Analysis (STPA), Events Sequence Identification (ETI) and Fault Tree Analysis (FTA). The developed method results into the development of a detailed Fault Tree that captures the effects of both the physical components/subsystems and the software functions’ failures. The quantitative step of the method employs the components’ failure rates to calculate the top event failure rate along with criticality analysis metrics for identifying the most critical components/functions. This method is implemented for an exhaust gas open loop scrubber system safety analysis to estimate its failure rate and identify critical failures considering the baseline system configuration as well as various alternatives with advanced functions for monitoring and diagnostics. The results demonstrate that configurations with SOx sensor continuous monitoring or scrubber unit failure diagnosis/prognosis lead to significantly lower failure rate. Based on the analysis results, the advantages/disadvantages of the novel method are also discussed. This study also provides insights for better safety analysis of the CPSs

A combinatorial safety analysis of cruise ship Diesel-Electric Propulsion plant blackout

Diesel-Electric Propulsion (DEP) has been widely used for propulsion of various ship types including cruise ships. Considering the potential consequences of blackouts, especially on cruise ships, it is essential to design and operate the ships power plants for avoiding and preventing such events. This study aims at implementing a comprehensive safety analysis for a cruise ship Diesel-Electric Propulsion (DEP) plant focusing on blackout events. The Combinatorial Approach to Safety Analysis (CASA) method is used to develop Fault Trees considering the black out as the top event, and subsequently estimate the blackout frequency as well as implement importance analysis. The derived results demonstrate that the overall blackout frequency is close to corresponding values reported in the pertinent literature as well as estimations based on available accident investigations. This study deduces that the blackout frequency depends on the number of operating Diesel Generators (DG) sets, the DG sets loading profile, the amount of electrical load that can be tripped during overload conditions and the plant operation phase. In addition, failures of the engine auxiliary systems and the fast-electrical load reduction functions as well as the power generation control components are identified as important. This study demonstrates the applicability of the CASA method to complex marine systems and reveals the parameters influencing the investigated system blackout frequency, thus providing better insights for these systems safety analysis and enhancement

Excessive weight gain after remission of depression in a schizophrenic patient treated with risperidone: case report

BACKGROUND: The use of atypical antipsychotics in schizophrenic patients has been associated with a risk of weight gain. Similarly, recovery from depression is often followed by improved appetite, greater food intake and potential increase in weight. CASE PRESENTATION: A Caucasian 33-year-old schizophrenic female patient was being treated with 6 mg/day of risperidone and 15 mg/day of clorazepate. She developed depressive symptomatology and 40 mg/day of fluoxetine was gradually added to her treatment regimen for about 9 months. After the remission of depression, and the discontinuation of fluoxetine, she experienced an increase in appetite and subsequently excessive weight gain of 52 kg. Re-administration of fluoxetine did not reverse the situation. The patient developed diabetes mellitus, which was successfully controlled with metformin 1700 mg/day. The addition at first of orlistat 360 mg/day and later of topiramate 200 mg/day has helped her to lose a significant part of the weight gained (30 kg). CONCLUSION: The case suggests a probable association between the remission of depressive symptomatology and weight gain in a schizophrenic patient

Paracrine signalling by cardiac calcitonin controls atrial fibrogenesis and arrhythmia

Atrial fibrillation, the most common cardiac arrhythmia, is an important contributor to mortality and morbidity, and particularly to the risk of stroke in humans1. Atrial-tissue fibrosis is a central pathophysiological feature of atrial fibrillation that also hampers its treatment; the underlying molecular mechanisms are poorly understood and warrant investigation given the inadequacy of present therapies2. Here we show that calcitonin, a hormone product of the thyroid gland involved in bone metabolism3, is also produced by atrial cardiomyocytes in substantial quantities and acts as a paracrine signal that affects neighbouring collagen-producing fibroblasts to control their proliferation and secretion of extracellular matrix proteins. Global disruption of calcitonin receptor signalling in mice causes atrial fibrosis and increases susceptibility to atrial fibrillation. In mice in which liver kinase B1 is knocked down specifically in the atria, atrial-specific knockdown of calcitonin promotes atrial fibrosis and increases and prolongs spontaneous episodes of atrial fibrillation, whereas atrial-specific overexpression of calcitonin prevents both atrial fibrosis and fibrillation. Human patients with persistent atrial fibrillation show sixfold lower levels of myocardial calcitonin compared to control individuals with normal heart rhythm, with loss of calcitonin receptors in the fibroblast membrane. Although transcriptome analysis of human atrial fibroblasts reveals little change after exposure to calcitonin, proteomic analysis shows extensive alterations in extracellular matrix proteins and pathways related to fibrogenesis, infection and immune responses, and transcriptional regulation. Strategies to restore disrupted myocardial calcitonin signalling thus may offer therapeutic avenues for patients with atrial fibrillation

Specific antenatal interventions for Black, Asian and Minority Ethnic (BAME) pregnant women at high risk of poor birth outcomes in the United Kingdom: a scoping review

Background: Disparity exists in maternal and infant birth outcomes of Black and Minority Ethnic (BAME) women giving birth in the United Kingdom (UK) compared to the majority. There is therefore a need to reconsider existing maternity service provision to ensure culturally competent services. The purpose of this scoping review was to ascertain what specific maternity interventions have been implemented in the UK for BAME women (2004–2014) so that increased awareness of the need and scope of specific maternity interventions for BAME women can be identified. Methods: A scoping review was conducted in order to determine the evidence base. It was determined that no prior systematic reviews had been conducted and it was apparent that literature in this field was sparse. Scoping review is an ideal method when literature is likely to be heterogeneous and the research field relatively unexplored. A keyword strategy was used implementing population (P), intervention (I), comparison (C) and outcomes (O). Results: An initial 2188 papers were identified. Following screening and review, only 5 heterogeneous papers remained suitable and were included. The included interventions employed sample sizes of N = 160-1441, examined a range of different outcome measures and were delivered across different parts of the UK with high numbers of BAME residents. Conclusions: There is a lack of rigorous research interventions and practice interventions which are currently documented, of specific maternity interventions which are aimed to address culturally competent maternity services and the sharing of best practice addressing the increased risks of BAME women delivering in the UK

Operational risk management of bulk carriers

The proposed study had been performed behind the premise of proposing a methodology for estimating the current operational risk of bulk carriers. Hence, a high level risk assessment has been conducted for evaluating the safety performance of dry bulk cargo transportation. This included the preparatory step for setting the problem's boundary limits, hazard identification for the prioritization of causes and effects, risk analysis for the quantification of risks and risk evaluation for assessing the significance and the acceptability of the estimated risk. The relevant aspects that are taken into account consist of the vessel's function (carriage of payload), operational phase (ocean transit), external weather conditions, routeing and internal (cargoes) influences, accident category foundering and the risk associated with crew (fatalities) and property (loss of vessel and cargo).EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Energy efficiency clauses in charter party agreements: legal and economic perspectives and their application to ocean grain transport

This book provides practical solutions for addressing energy efficiency as a clause term within a charter party contract. For this, upon a reflection of the regulatory craft, it analyzes key concepts of case law, and discusses them together with commercial and economic principles. In this way, the book aims at offering a comprehensive, interdisciplinary view of the chartering process, together with a new approach for safeguarding energy efficiency investments. A special emphasis is given to the maritime industry. Here, the newly developed framework, based on game theory, has been successfully applied to demonstrate the importance of including a clause term in contract negotiation to achieve protection against both an uncertain market and an even more challenging shipping environment. The book not only fills a gap in the literature, covering a topic that has been largely neglected to date, yet it offers researchers and practitioners extensive information to change the chartering process radically

Λειτουργική διαχείριση διακινδύνευσης πλοίων μεταφοράς χύδην φορτίου

The proposed study had been performed behind the premise of proposing a methodology for estimating the current operational risk of bulk carriers. Hence, a high level risk assessment has been conducted for evaluating the safety performance of dry bulk cargo transportation. This included the preparatory step for setting the problem's boundary limits, hazard identification for the prioritization of causes and effects, risk analysis for the quantification of risks and risk evaluation for assessing the significance and the acceptability of the estimated risk. The relevant aspects that are taken into account consist of the vessel's function (carriage of payload), operational phase (ocean transit), external (weather conditions, routeing) and internal (cargoes) influences, accident category (foundering) and the risk associated with crew (fatalities) and property (loss of vessel and cargo). Apparently, many factors were competing for attracting attention, and therefore, the Pareto principle was applied for narrowing the analysis where corrosion was identified as a main situation of causing harm. The attached uncertainty in the aforementioned operational domain is dealt with the Bayesian Networks technology and concurrently the construed prioritization to corrosion is verified by the developed risk model. The estimated risk was found As Low As Reasonably Practicable and the potential of improvement is considered by addressing preventive (design) and mitigating (operational) measures. Furthermore, their effectiveness as action implementing risk management decision is illustrated by employing Life Cycle Cost Analysis, a decision making technique for exploiting different investment opportunities.Η προτεινόμενη μελέτη είχε εκτελεστεί πίσω από την προϋπόθεση της πρότασης μεθοδολογίας για την εκτίμηση την τρέχουσα λειτουργική διακινδύνευση των πλοίων μεταφοράς χύδην φορτίου. Ως εκ τούτου, έχει διεξαχθεί μια αξιολόγηση διακινδύνευσης υψηλού επιπέδου για την αξιολόγηση της απόδοσης ασφάλειας της μεταφοράς ξηρού χύδην φορτίου. Αυτό περιλάμβανε το προπαρασκευαστικό βήμα για τον καθορισμό των ορίων του προβλήματος, τον προσδιορισμό κινδύνου για την ιεράρχηση των αιτιών και των αποτελεσμάτων, την ανάλυση διακινδύνευσης για την ποσοτικοποίηση της διακινδύνευσης και την εκτίμηση διακινδύνευσης για την αξιολόγηση της σημασίας και της αποδοχής της εκτιμώμενης διακινδύνευσης. Οι σχετικές πτυχές που λαμβάνονται υπόψη αποτελούνται από τη λειτουργία του σκάφους (μεταφορά ωφέλιμου φορτίου), τη φάση λειτουργίας (θαλάσσια μεταφορά), τις εξωτερικές (καιρικές συνθήκες, πορεία) και τις εσωτερικές (φορτία) επιρροές, την κατηγορία ατυχήματος (βύθιση) και την διακινδύνευση που σχετίζεται με πλήρωμα (θανάτων) και περιουσία (απώλεια πλοίου και φορτίου). Προφανώς, πολλοί παράγοντες συναγωνίζονταν για να προσελκύσουν την προσοχή, και ως εκ τούτου, εφαρμόστηκε η αρχή Pareto για τον περιορισμό της ανάλυσης όπου η διάβρωση αναγνωρίστηκε ως η κύρια κατάσταση πρόκλησης βλάβης. Η συνημμένη αβεβαιότητα στον προαναφερθέντα λειτουργικό τομέα αντιμετωπίζεται με την τεχνολογία Bayesian Networks και ταυτόχρονα η ερμηνευόμενη ιεράρχηση στη διάβρωση επαληθεύεται από το αναπτυγμένο μοντέλο διακινδύνευσης. Ο εκτιμώμενος κίνδυνος βρέθηκε τόσο χαμηλός όσο εύλογα πρακτικός και η δυνατότητα βελτίωσης εξετάζεται με την αντιμετώπιση προληπτικών (σχεδιασμού) και μετριασμού (επιχειρησιακών) μέτρων. Επιπλέον, η αποτελεσματικότητά τους ως δράσης υλοποίησης απόφασης διαχείρισης διακινδύνευσης απεικονίζεται χρησιμοποιώντας την Ανάλυση Κόστους Κύκλου Ζωής, μια τεχνική λήψης αποφάσεων για την εκμετάλλευση διαφορετικών επενδυτικών ευκαιριών

Risk acceptance criterion for tanker oil spill risk reduction measures

This paper is aimed at investigating whether there is ample support for the view that the acceptance criterion for evaluating measures for prevention of oil spills from tankers should be based on cost-effectiveness considerations. One such criterion can be reflected by the Cost of Averting a Tonne of oil Spilt (CATS) whereas its target value is updated by elaborating the inherent uncertainties of oil spill costs and establishing a value for the criterion’s assurance factor. To this end, a value of $80,000/t is proposed as a sensible CATS criterion and the proposed value for the assurance factor F = 1.5 is supported by the retrieved Protection and Indemnity (P&I) Clubs’ Annual Reports. It is envisaged that this criterion would allow the conversion of direct and indirect costs into a non-market value for the optimal allocation of resources between the various parties investing in shipping. A review of previous cost estimation models on oil spills is presented and a probability distribution (log-normal) is fitted on the available oil spill cost data, where it should be made abundantly clear that the mean value of the distribution is used for deriving the updated CATS criterion value. However, the difference between the initial and the updated CATS criterion in the percentiles of the distribution is small. It is found through the current analysis that results are partly lower than the predicted values from the published estimation models. The costs are also found to depend on the type of accident, which is in agreement with the results of previous studies. Other proposals on acceptance criteria are reviewed and it is asserted that the CATS criterion can be considered as the best candidate. Evidence is provided that the CATS approach is practical and meaningful by including examples of successful applications in actual risk assessments. Finally, it is suggested that the criterion may be refined subject to more readily available cost data and experience gained from future decisions

Under-reporting of maritime accidents

The majority of current maritime regulations has been developed following a reactive approach, often as ad-hoc response to serious accidents, and are characterised as being prescriptive leaving limited space for adapting equivalent solutions rather those described in the regulations. On the premise of providing a more proactive approach for the proposal or the evaluation of regulations, the Formal Safety Assessment (FSA) has been introduced. In the context of FSA, the analysis of accident data is considered to be very important for providing potential input on developing more balanced, proactive and cost-effective regulations. However, it has been argued that the validity of historical data may be undermined by uncertainties. This paper is aimed at showing evidence on serious under-reporting in accident databases, which can be considered as the main contributor to questioning the direct and uncritical use of historical data. By analysing the 10-year tanker accident data from the Lloyd\u27s Register FairPlay (LRFP) and the Norwegian Maritime Directorate (NMD) for vessels registered in Norway, it is found that the reporting performance has an upper bound of 41% for NMD and 30% for LRFP. Furthermore, based on comparison between LRFP data and self-assessment by Flag States, it is seen that accidents reported by the Flag States are also incomplete