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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Using Bayesian networks to represent parameterised risk models for the UK railways

Bearfield, George Joseph January 2009 (has links)
The techniques currently used to model risk and manage the safety of the UK railway network are not aligned to the mechanism by which catastrophic accidents occur in this industry. In this thesis, a new risk modelling method is proposed to resolve this problem. Catastrophic accidents can occur as the result of multiple failures occurring to all of the various defences put in place to prevent them. The UK railway industry is prone to this mechanism of accident occurrence, as many different technical, operational and organizational defences are used to prevent accidents. The railway network exists over a wide geographic area, with similar accidents possible at many different locations. The risk from these accidents is extremely variable and depends on the underlying conditions at each particular location, such as the state of assets or the speed of trains. When unfavourable conditions coincide the probability of multiple failures of planned defences increases and a 'risk hotspot' arises. Ideal requirements for modelling risk are proposed, taking account of the need to manage multiple defences of conceptually different type and the existence of risk hotspots. The requirements are not met by current risk modelling techniques although some of the requirements have been addressed experimentally, and in other industries and countries. It is proposed to meet these requirements using Bayesian Networks to supplement and extend fault and event tree analysis, the traditional techniques used for risk modelling in the UK railway industry. Application of the method is demonstrated using a case study: the building of a model of derailment risk on the UK railway network. The proposed method provides a means of better integrating industry wide analysis and risk modelling with the safety management tasks and safety related decisions that are undertaken by safety managers in the industry.
2

Atherosclerosis of the ascending aorta as a risk factor for stroke after cardiac surgery : a study based on epiaortic ultrasound /

Bergman, Per, January 2004 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 5 uppsatser.
3

Mileage-based accident risks of pedelec riders

Gaster, Kristina, Gehlert, Tina 19 December 2022 (has links)
In a previous paper, we analyzed accidents of pedelec riders in 2019 and examined possible changes over the past years. We found that pedelec accidents still essentially resemble the classic two-wheeler accident characteristics, with certain specifics (e.g., higher age of riders involved in an accident, higher proportion of single-bicycle accidents, higher proportion of out-of-town accidents). Even though the number of pedelecs and pedelec accidents has increased in recent years, no qualitative changes in the characteristics of accidents compared to previous years seem to have occurred. We now have a large data base of riders and accidents and new data sources that offer the possibility for calculating accident risks by mileage-based analyses. In addition to absolute accident numbers, relative accident parameters are of particular interest for accident research and prevention. Using the same amount of physical effort pedelecs can be used to cover longer distances than bicycles. At the same time, longer distances increase the probability of being involved in an accident. On average, pedelec users cover 1.8 times as many kilometers per day as bicycle users do. We now have nationally representative data on the mileage of pedelec riders, so we can calculate mileage-based accident risks and get new insight into pedelec accidents. For comparison the accident risks of bicycle riders are used.
4

An Innovative Model Integrating Spatial And Statistical Analyses For A Comprehensive Traffic Accident Study

Sener, Ipek Nese 01 June 2005 (has links) (PDF)
The negative social and economic results of traffic accidents are the most serious problems within the concept of traffic safety. Every year, unfortunately, a huge number of traffic accidents result in destructive losses. Especially, when the holiness of human life is concerned, traffic safety has an invaluable role for the traffic improvement strategies. In this manner, Turkey places one of the highest ranks regarding the growing rate and severity of traffic accidents that should be immediately taken under control. In this study, an innovative model that constructs a hybrid between the spatial and statistical analyses is developed in order to examine the importance of enhancing statistical analysis with georeferenced data and so location-based studies in traffic accident analysis. Meanwhile, the effects of road characteristic and environment are considered for exploring the integral role of roadway factor to the occurrence of accidents, and consequently for emphasizing easily applicable and controllable engineering safety measures. Because of the rare and random distribution of traffic accident data, logistic regression is used for the statistical part of the study in order to find the pairwise risk factors among the roadway and environmental parameters. After unifying these relative risk factors with the logic of Analytic Hierarchy Process, the finalized accident risk factors are attached to the digitized road characteristics map through Geographic Information Systems (GIS). The abilities of GIS in mapping, displaying and overlaying different data sets ensure to visualize high risked accident areas with their corresponding potential causal factors. The integration of statistical and spatial analyses is essential for developing appropriate and effective precautions in addition to its easily understandable, applicable and modifiable structure. Finally, the model is proven to be appropriate for both interpreting the existing traffic accident problem or potential future accidents and also developing comprehensive and reliable location-based safety studies.
5

Havarijní připravenost v chemickém podniku Synthos Kralupy a.s. při úniku nebezpečných látek / Emergency preparedness in the chemical enterprise Synthos Kralupy a.s. in the release of hazardous substances

TYEMNYÁKOVÁ, Lucie January 2017 (has links)
The risk of serious accident is increasing with the rise of the amount of chemical industry manufacturing. This accident can have immeasurable consequences. The aim of this thesis is to point out the consequences caused by leakage of dangerous substance of petrol from the biggest cistern in chemical company Synthos Kralupy a.s. and to suggest steps for emergency clearance. To fulfil the aim, examination of serious accident risks had to be carried out first. The method of Dow's Fire and Explosion Index was used for this examination which enabled evaluation of a real fire and explosion risk. Apart from these methods, another method called IAEA-TECDOC-727 was also used. Consequently, possible scenarios of dangerous substances leakage from storage cistern were created. These were simulated through software programmes ALOHA and TerEx. Acquired results were then well arranged in charts. During the research of this issue, a method of controlled interviews was used. These interviews with employees of firefighter emergency service were focused on emergency readiness of the chemical company Synthos Kralupy a.s. A cistern containing dangerous substance represents a crucial risk, even though the results showed that the accident of all petrol leakage from the cistern is very unlikely. However, this accident should not be neglected because a dangerous cloud reaching 565 m from the site of the accident would occurred. The dangerous cloud cause mortality of 70% within a distance of 2,000 m and a distance of 4,970 m to the 1 st degree burns. If all petrol leaked from the cistern, the consequences would be much bigger than just pollution. It would also include death toll, health problems and vast property damages.
6

Bezpečnostní inspekce na vybraných lokalitách v Olomouckém kraji / Road safety inspection in the 0lomouc region

Nováková, Kristýna January 2018 (has links)
The diploma thesis focuses on a road safety inspection of selected intersections in Olomouc Region. The first step of the diploma thesis was to select 20 intersections, then each one was subjected to accident analysis. The intersections were compared by accident indicators, which were the basis of selection 11 intersections for visual inspection purposes. Based on visual inspections, the selection was further reduced to 4 intersections in Olomouc Region, which were subjected to detailed road safety inspection, then the potential risks influencing the origins of accident were identified and corrective measures were proposed in order to remove or eliminate the intersections problems.
7

Řízení rizika zhotovitele stavební zakázky / Risk Management Contractor Construction

Štráchal, Jakub January 2013 (has links)
THE AIM OF MY THESIS ON THE TOPIC OF "RISK MANAGEMENT CONTRACTOR CONSTRUCTION CONTRACTS" IS TO DESCRIBE THE PROCESS OF RISK MANAGEMENT OF CONTRACTOR CONSTRUCTIONS WORK. THIS PROCESS BEGINS WITH THE IDENTIFICATION OF RISKS BY USING DIFFERENT METHODS. FOLLOWED BY ANALYSIS OF THESE RISKS. THE MAIN GROUP OF RISKS ARE RISKS ASSOCIATED WITH THE SUBCONTRACTING SYSTEM. THESE RISKS I WILL DESCRIBE THEIR SIGNALS AND TRIGGERS. ON THE BASIS OF THEIR IMPORTANCE TO THE PROJECT, I WILL DEFINE THE MANNER OF THEIR TREATMENT. IN THE LAST PART IS A PROPOSAL OF A MONITORING RISKS, WHERE I SUGGEST A WAY, WHO WILL LOOK AFTER THE RISKS DURING THE CONSTRUCTION AND WHEN.
8

Design and implementation of an affordable reversing camera system with object detection and OBD-2 integration for commercial vehicles / Design och implementering av ett prisvärt backkamerasystem med objektdetektering och OBD-2-integration för kommersiella fordon

Ebrahimi, Alireza, Akbari, Esmatullah January 2023 (has links)
This thesis is about designing and implementing an affordable reversing camera sys-tem with object detection and OBD-2 integration for commercial vehicles. The aim is to improve the safety and efficiency of these vehicles by giving drivers a clear view of their surroundings behind the vehicle and alerting them to the presence of nearby obstacles. Ultrasonic sensors are used for object detection and give the driver control over the environment behind the vehicle and warn of present obstacles. The system is also integrated with the vehicle's on-board diagnostics system (OBD-2), which provides important information on speed and engine performance, among other things. This project contributes to making safety systems more accessible to com-mercial vehicles and reduces the risk of accidents and collisions. / Detta examensarbete handlar om att utforma och implementera ett prisvärt backkamerasystem objektdetektering och integration med On-Board Diagnostics 2 för kommersiella fordon. Syftet är att förbättra säkerheten och effektiviteten för dessa fordon genom att ge förarna en tydlig vy av deras omgivningar bakom fordonet och varna dem för närvaron av hinder i närheten. Ultraljudssensorer används för objekt-detektering och ger föraren en kontroll över omgivningen bakom fordonet samt var-nar för närvarande hinder. Systemet är också integrerat med fordonets omborddia-gnostiksystem (OBD-2), som ger viktig information om bland annat hastighet och motorprestanda. Detta projekt bidrar till att göra säkerhetssystem mer tillgängliga för kommersiella fordon och minskar risken för olyckor och kollisioner.
9

Regionale Verteilung von Fahrradunfällen auf dem Schulweg in Bayern

Renner, Simon 05 December 2016 (has links)
Eine Auswertung der Unfallzahlen der Kommunalen Unfallversicherung Bayerns von 2007 bis 2011 zeigte, dass es innerhalb Bayerns große regionale Unterschiede im fahrradbezogenen Unfallgeschehen auf dem Schulweg gibt. Durch ein mehrstufiges multimethodisches Studiendesign wurde der Frage nachgegangen, ob es in den unfallbelasteten Landkreisen tatsächlich gefährlicher ist mit dem Rad zur Schule zu fahren und nach den Ursachen der räumlichen Diskrepanzen gesucht. Mittels regressionsanalytischer Verfahren konnte ein Großteil der räumlichen Varianz der Unfallraten auf die unterschiedlichen Voraussetzungen zum Radfahren zurückgeführt werden: Je weiter und je hügeliger der Weg zur Schule ist, umso weniger Unfälle ereignen sich, wobei vermutet werden kann, dass dieser Zusammenhang Folge der niedrigen Radnutzung ist. Doch auch bei Landkreisen mit ähnlichen Radfahrbedingungen, etwa bei den kreisfreien Mittelstädten Rosenheim und Schweinfurt, lassen sich große Unterschiede im fahrradbezogenen Unfallgeschehen feststellen. Um zu überprüfen, ob auch hierfür die variierende Radnutzung verantwortlich ist, fand im Rahmen einer Fall-Kontroll-Studie eine Messung der Schulwegmobilität in diesen beiden Städten statt, wodurch das jeweilige expositionsbereinigte Unfallrisiko berechnet werden konnte. Die Erhebung zeigte, dass die distanz- und zeitbezogenen Inzidenzraten der beiden Untersuchungsregionen nahezu identisch sind. Dies belegt, dass das Unfallgeschehen hauptsächlich von der Radnutzung abhängt, wobei die Ursachen für die abweichende Radnutzung durch eine Schüler- und Lehrerbefragung empirisch untersucht wurde. Unfallschwerpunkte im Schülerradverkehr sind also statistische Artefakte, da aus der Unfallrate ohne die Kenntnis der Radnutzung auf das Unfallrisiko geschlossen wurde. Regionsunabhängig aber ist das fahrradspezifische Unfallrisiko auf Schulwegen deutlich höher als etwa auf dem Weg zur Arbeit, was die Dringlichkeit verdeutlicht, präventiv tätig zu werden. / Analyzing the number of accidents between 2007 and 2011, registered by the Kommunale Unfallversicherung Bayern, revealed great regional differences in bicycle traffic accidents on the way to school in Bavaria. A multi-stage, multi-methodical study design was set up to find answers to the question, if it is actually more dangerous to cycle to school in districts with high accident rates. The reasons for regional discrepancies in these accident rates were identified, while a varying rate of bicycle use was detected the main cause for interregional differences in the number of accidents.Regression analysis indicated that the majority of spatial variance in accident rates is based on different cycling conditions; the further and more hilly the way to school, the less accidents occur. However, it can be assumed that this correlation is a consequence of lower bicycle use. On the other hand in regions with similar cycling conditions great differences in bicycle traffic accidents can be observed, which the study shows for the district-free, mid-sized cities Rosenheim and Schweinfurt. This case-control-study on the way-to-school mobility measured for the two cities the exposition-adjusted risk of accident and was performed to reveal if this effect is also caused by varying bicycle use rates. The study pinpointed the fact that distance- and time-related incidence rates are almost identical in both study regions,which is an evidence for bicycle use rates mainly affecting the number of accidents. The reasons for differing bicycle usage were examined empirically by questioning pupils and teachers. As a conclusion, accident black spots in pupils` bicycle traffic are statistical artefacts, as the accident risk was gathered from the accident rate without knowing bicycle use rates. However, regardless of the region, cycling to school is remarkably more dangerous than cycling to work, a fact that underlines the urgency to act preventively.
10

Hållbarhetsanalys av ett cykelinfrastrukturprojekt inom Stockholms stad : Utvärdering av ett cykelinfrastrukturprojekt via samhällsekonomisk nyttoanalys

Book, Tony, Svensson, Sofia January 2015 (has links)
Att sträva mot en hållbar utveckling, inom alla dess aspekter, är i dagsläget högst aktuellt. Särskilt då medvetenheten ökat kring de negativa effekter som exempelvis utsläpp, föroreningar och buller ger upphov till. Dessa effekter finns alla närvarande när man utvecklar en av samhällets allra mest vitala funktioner, nämligen transportinfrastruktur. Transportsystemen är, och har länge varit, ohållbara då bilar och andra motorfordon, som har stor miljöpåverkan, har prioriterats. För att minska utsläppen från transporter har Europeiska kommissionen uttryckt att andra typer av transportmedel, som kollektivtrafik, gång och cykling, bör ges högre prioritet. Flera stora städer i Europa har infört cykelvisioner och planer för att förbättra möjligheterna för att just cykla. Stockholm är en av dessa städer och en handfull projekt har därför införts för att rusta upp stadens cykelnät. Trots dessa cykelsatsningar görs dock få hållbarhetsanalyser av cykelinfrastrukturprojekt, vilket kan vara problematiskt då beslutsfattare ofta saknar adekvat underlag för att motivera investeringar. Arbetet har undersökt den sociala, ekonomiska och ekologiska hållbarheten hos ett cykelinfrastrukturprojekt genom att jämföra projektets investeringskostnad mot dess samhällsvinster via kostnads- och nyttoanalys (CBA). Projektet som har undersökts innefattar en byggnation av en 400 m lång gång- och cykelbana längs Skärholmsvägen i sydvästra Stockholm. Tidigare har vägen kantats av cykelfält på vardera sida och ingen gångväg har funnits längs sträckan. Projektet väntas vara klart under 2015 och beräknas kosta 4,16-5 miljoner kronor. Vid CBA utreds inledningsvis vilka effekter, som projektet ger upphov till, som ska beaktas i analysen. I detta arbete har hälsovinst, tidsvinst, bekvämlighetsvinst, olycksriskskillnad och miljövinst analyserats. Efter att effekterna kvantifierats omvandlas dessa kvantiteter till monetära termer för att kunna jämföras med projektets budget. Värdet för hälsovinster ges av minskad dödsrisk och värdet av ett statistiskt liv (VSL), tidsvinsten fås av ökad medelhastighet, bekvämlighetsvinsten beräknas genom att cyklisterna separeras från biltrafik, olycksriskskillnaden ges av förändringar i cyklisternas trafiksituation och miljövinsten fås av den andel nytillkomna cyklister som tidigare pendlade via bil. Projektet kommer, enligt utförda beräkningar, resultera i en samhällsnytta på mellan 1,05 miljoner kronor och 2,88 miljoner kronor beroende på mängden genomförda antaganden. Den effekt som bidrog mest till denna nytta är hälsoeffekter med ett bidrag på mellan 919 000 kr och 2,76 miljoner kr. Den effekt som bidrog med minst nytta är miljövinst med ett bidrag på mellan 168 kr och 630 kr. Nyttan kan sedan jämföras med projektets budget vilken förmodas minst uppgå till 4.16 miljoner kronor. Den planerade kostnaden för projektet uppgår dock till 5 miljoner kronor. Projektet kommer alltså slutligen ge upphov till en samhällskostnad på mellan 1,28 miljoner kr och 3,95 miljoner kr enligt genomförda beräkningar. Projektet kan möjligtvis anses vara samhällsekonomiskt gångbart om den procentuella bredden av gångbanan även motsvarar dess procentuella kostnad. Sedan miljöeffekten för projektet blev försumbar jämfört med övriga effekter kan ytterligare analysverktyg dock behövas för att vidare bedöma projektets miljöpåverkan. Detta är en indikation på att CBA är ett ofullständigt analysverktyg för att bedöma hållbarhet vad gäller cykelinfrastrukturprojekt. / Striving towards sustainable development, in all of its aspects, is currently exceedingly relevant. Particularly since the awareness of the negative side effects caused by emissions, pollution and noise have increased. These effects are all present while developing one of society’s most vital functions, namely transport infrastructure. The transport system is, and has long been, unsustainable as cars and other motor vehicles, having a large environmental impact, have been prioritized. To reduce transport emissions the European Commission has stated that other modes of transportation, such as commuting, walking and cycling, should be given higher priority. Several major European cities have implemented visions and plans to improve the possibility to bicycle. Stockholm is one of these cities and a handful of projects have thus been implemented to renovate the city’s cycling network. Despite these bicycle investments few sustainability analyses are made for bicycle infrastructure projects, which can be problematic since decision makers often lack proper support to justify investments. This work has examined the social, economic and ecological sustainability of a bicycle infrastructure project by comparing the investment costs of the project against its social benefits in a cost-benefit analysis (CBA). These benefits include health, time, comfort, accident risk and environment, which have been calculated through a cost benefit analysis (CBA). The examined project consists of a roughly 440 yard path for pedestrians and bicyclists located along Skärholmsvägen, southwest of the Stockholm city centre. Previously the road was lined with two bicycle fields on either side of the road with no path for pedestrians existing prior to the renovation. The project is planned to end during 2015 and the estimated cost amounts to 4,16-5 million SEK. In a CBA the effects which the project generates are initially investigated to assess which of the effects to consider in the analysis. In this work, health benefits, time benefits, comfort benefits, traffic accidents and environmental benefits have been analyzed. After the effects have been quantified these quantities are converted into monetary values to enable a comparison between the effects and the budget of the project. The value for health benefit is determined through decreased mortality risk and the value of a statistical life (VSL), the time benefit is calculated through an increased average velocity, the comfort benefit is determined through separating cyclists from car traffic, accident risk is estimated through the change in the bicyclists traffic conditions and the environmental benefit is calculated through the share of new cyclists who previously commuted by car. The project will, according to performed calculations, result in a societal benefit of in between 1.05 million SEK and 2.88 million SEK depending on the amount of performed assumptions. The effect which contributed the most to this benefit is the health benefit with a contribution of in between 919,000 SEK and 2.76 million SEK. The effect which contributed the least to the societal benefit is the environmental benefit with a contribution of in between 168 SEK and 630 SEK. The benefit can then be compared with the budget of the project which is estimated to amount to at least 4.16 million SEK. However the planned cost for the project amounts to 5 million SEK. The project will thus eventually yield a societal cost of in between 1.28 million SEK and 3.95 million SEK according to the calculations performed. The project can possibly be considered sustainable if the percentage of the width of the path corresponds to the percentage of its cost. Since the environmental effect could be neglected in this project compared to the other effects additional tools would thus be required to assess the environmental aspects of the project. This is an indication of CBA being an incomplete analysis tool to assess sustainability.

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