This research has first established that it is based on multiple methodologies developed to tackle the areas of engineering cargo handling systems, both at port and on-board vessels, as well as in the area of organisational self-assessment. It continued in reviewing the current status and future aspects of marine safety assessment together with an examination of a few major accidents. The major problems identified in marine safety assessment in this research are associated with inappropriate treatment of uncertainty in data and human error issues during the risk modelling estimation process and the calculation of failure probabilities. Following the identification of the research needs, this thesis has developed several analytical models for the safety assessment of cargo handling systems and organisational assessment structure. Such models can be effectively integrated into a risk-based framework using the marine formal safety assessment, safety case concepts. Bayesian network (BN) and evidential reasoning (ER) approaches applicable to cargo handling engineering systems have been proposed for systematically and effectively addressing uncertainty due to randomness and vagueness in data respectively. ER test cases for both a vessel selection process and a comparison of the safety maturity of different organisations in terms of self-assessment have been produced within a domain in which main and sub criteria have been developed for assessment reasons a long with the combination of the proposed model with existing organisational models. BN test case for a Liquefied Petroleum Gas (LPG) reliquefaction plant has been produced within a cause-effect domain in which Bayes' theorem is the focal mechanism of inference processing. A methodology aiming in finding the probability of failure when having variables ruled by uncertainty is established using certain variable transformation methods through the First and Second order reliability methodologies. Form/Sorm produces a most likely failure point, which is demonstrated through the application at a port cargo handling crane system. The outcomes have the potential to facilitate the decision-making process in a risk-based framework. Finally, the results of the research are summarised and areas where further research is required to improve the developed methodologies are outlined.

Recent high profile accidents involving environmental damage caused by structural failures in ageing oil tankers and bulk carriers has highlighted the importance of structural integrity issues involving these types of ships. Between 1980 and 1996, there were 186 total losses of bulk and combination carriers and 1,278 lives lost. These events have led to concerns from the public, media and within the international maritime community, about deteriorating ship structural safety standards and the environmental impact. Evidence suggests that structural failure may account for more ship losses than hitherto believed. Industry critics have complained that the quality of designs for new tonnage and effectiveness of the present control mechanisms governing structural condition for vessels in service, are inadequate. Due to the relatively low safety margins inherent in modern commercial ship structural designs, a buyer beware policy prevails in ship procurement. A weakness in current ship design practice appears to be the difficulty of incorporating an owner's individual preferences. Recognising that to be effective, improvements in ship structural design must be implemented at the design stage, this study addresses the challenge of further improving the structural safety and performance of large bulk ships through exercising specific options related to the structural design of the ship within the remit of the buyer. A broad comprehensive literature survey was conducted to cast a wide net around the problem. The complex web of regulatory controls affecting the design and operation of bulk ship hull structures was analysed and problems involving design, construction and maintenance of these vessels were uncovered to build evidence to justify proposing an improved method. An analysis of recent high profile tanker and bulk carrier accidents involving structural failure was performed, to determine root causes. These findings formed the basis for a proposed novel risk-based "design for safety" framework The core of the method is the new evidential reasoning (ER) algorithm developed on the basis of a MCDA evaluation framework and the evidence combination rule of the Dempster-Shafer (D-S) Theory. A number of structural design options focused on the cargo tank mid body area of a typical double hull VLCC were evaluated. A set of quantitative and qualitative criteria were identified and articulated, leading to a structural evaluation framework for eliciting preferences for competing options. The MCDAlER model provides a risk-based, rational, transparent methodology for rapid techno-economic evaluation of alternative structural designs, putting buyers in a stronger position to balance risks and determine the expected structural safety outcomes of different designs. The ER modelling is performed using the Intelligent Decision System (IDS) software program developed by Yang and Xu. The method was tested with an example and validated through a sensitivity study. Finally, the evidence necessary for constructing and demonstrating the MCDAlER structural evaluation framework was used to build the arguments for a safety case approach to hull structures using the Australian Offshore safety case model. The safety case for hull structures is built upon a foundation of existing prescriptive statutory and classification society structural regulatory requirements. The advantages of the safety case applied to oil tankers were explained, including suggestions for a new regulatory approach. The application of new technology and tools was discussed.

No description available.

This research has evaluated the rules, guidelines and regulations related to ship vibrations. A historical failure data analysis is carried out to identify associated components, equipment and the areas of defects related to ship vibration problems. Ship Hull Vibration (SHV) is recognised as a major problem onboard ships and the propulsion system is identified as the major contributor to SHV. The current status of ship vibrations is reviewed and possible sources which create SHV are recognised. The major problems identified in this research are associated with risk modelling under circumstances where high levels of uncertainty exist. Following the identification of research needs, this PhD thesis has developed several analytical models for the application of Formal Safety Assessment (FSA). Such mode quently demonstrated by their corresponding case sti vith regard to application of FSA for SHV modelling. Firstly, in this research a generic SHV model is constructed for the purpose of risk estimation based on the identified hazards. The hazards include the SHV effects induced by ship design criteria, failure of components, and different patterns associated with the ship propulsion system (propeller system and machinery) as the major contributors to SHV. Then risk estimation bn is carried out utilising Evidential Reasoning (ER) and a fuzzy rule base. Secondly, ship selection (decision making) is investigated to to select the best ship design based on the risk estimation results of SHV. The risk estimation is carried out using ER, a fuzzy rule base and continuous fuzzy sets. The best ship design is selected by taking into account an ER-based utility ranking approach. Thirdly, combining discrete fuzzy sets and an Analytical Hierarchy Process (AHP) risk estimation is conducted in terms of four risk parameters to select the major causes of component failure and then SHV.

No description available.

Att få anordna ett världsmästerskap i fotboll ses som en stor ära, då det bygger upp förväntningar en nation, eller flera, kan bygga en gemenskap omkring. I juli år 2000 valdes Tyskland som arrangör till mästerskapet i fotboll år 2006 och således började förberedelser ta fart. Syftet med denna uppsats är studera huruvida fotbolls-VM i Tyskland (2006) var ett samhällsekonomiskt lönsamt projekt eller inte. Tidigare studier i området pekar på att det finns en överskattning i de nettofördelar som landet visar sig få. I studien kommer en nytto-kostnadsanalys (CBA) att utföras där relevanta nyttor och kostnader lyfts fram och ställs mot varandra. Kostnadssidan är mer tillförlitlig då de största utgifterna är officiella, medan nyttosidan inte är lika tillförlitlig på grund av att många siffror är estimerade. Dessutom finns det nyttor som inte kan räknas i monetära-termer (n.m) vilket också försvårar analysen. Slutligen pekar resultatet på att det inte var samhällsekonomiskt lönsamt för Tyskland att arrangera mästerskapet då kostnaderna övervägde nyttorna. För enskilt året 2006, kan det dock ses som samhällsekonomisklönsamt på grund av kostnadsfördelningen på fem år på de stora kostnadsposterna. / Organising a World Cup is seen as a great honour, as it builds up expectations and is something that one or more nations can build a community around. In July 2000, Germany was chosen to host the championship and so preparations began to take off. The purpose of this paper is to study whether the World Cup was socio-economically profitable or not in Germany (2006). Previous studies in this area indicate that there is an overestimation of the net benefits that the country will receive. In this study, a cost-benefit analysis (CBA) will be carried out where relevant benefits and costs are highlighted and compared. The cost side is more reliable as the largest expenditures are official, while the benefit side is less reliable as many figures are estimated. In addition, some benefits cannot be calculated in monetary terms, which also complicates the analysis. Finally, the result indicates that it was not a socio- economic benefit for Germany to organise the FIFA World Cup as the costs outweighed the benefits. However, only looking on the year of 2006, it can be seen as socio-economically profitable due to the five-year cost distribution of the main cost items.

No description available.

Understanding user and system behavior is most vital for designing efficient systems. Most systems are designed with certain user workload in mind. However, such workloads evolve over time, or the underlying hardware assumptions change. Further, most modern systems are not built or deployed in isolation, they interact with other systems whose behavior might not be exactly understood. Thus in order to understand the performance of a system, it must be inspected closely while user workloads are running. Such close inspection must be done with minimum disturbance to the user workload. Thus tracing or collection of all the user and system generated events becomes an important approach in gaining comprehensive insight in user behavior. As part of this work, we have three major contributions. We designed and implemented an in-depth block level I/O tracer, which would collect block level information like sector number, size of the I/O, actual contents of the I/O, along with certain file system information like filename, and offset in the file, for every I/O request. Next, to minimize the impact of the tracing to the running workload, we introduce and implement a sampling mechanism which traces fewer I/O requests. We validate that this sampling preserves certain I/O access patterns. Finally, as one of the application of our tracer, we use it as a crucial component of a system designed to do VM placements according to user workload. / Master of Science

Virtualization is the key technology that has provided the Cloud computing platforms a new way for small and large enterprises to host their applications by renting the available resources. Live VM migration allows a Virtual Machine to be transferred form one host to another while the Virtual Machine is active and running. The main challenge in Live migration over WAN is maintaining the network connectivity during and after the migration. We have carried out live VM migration over the WAN migrating different sizes of VM memory states and presented our solutions based on Open vSwitch/VXLAN and Cisco GRE approaches. VXLAN provides the mobility support needed to maintain the network connectivity between the client and the Virtual machine. We have setup an experimental testbed to calculate the concerned performance metrics and analyzed the performance of live migration in VXLAN and GRE network. Our experimental results present that the network connectivity was maintained throughout the migration process with negligible signaling overhead and minimal downtime. The downtime variation experience with change in the applied network delay was relatively higher when compared to variation experienced when migrating different VM memory states. The total migration time experienced showed a strong relationship with size of the migrating VM memory state. / 0763472814

Purpose – The purpose of this paper is to explore the possibility to effectivize local networks and databases using unikernels and compare this to containers. This could also apply to reliability of executing programs the same way on different hardware in software development. Method – Two experiments have been performed to explore if the purpose could be realized, quantitative data have been gatheredand displayed in both cases. Python-scripts have been used to start C-scripts, acting client and server. Algorithms have been timed running in unikernels as well as in containers along with compared measurements of memory in multiple simultaneous instantiations. Findings – Intermittent response times spiked made the data hard to parse correctly. Containers had a lower average response time when running lighter algorithms. The average response times of unikernels dives below that of containers when heavier programs are simulated. Few minor bugs were discovered in Unikraft unikernels. Implications – unikernels havecharacteristics that make them more suitable for certain tasks compared to their counterpart, this is also true for containers. Unikraft unikernels are unstable which makes it seem like containers are faster during lighter simulations. Unikernels are onlyfaster and more secure if the tools used to build them does so in a manner that makes them stable. Limitations – The lack of standards, the lack of a support community together with the fact that unikernels is a small and niche field means that unikernels have a relatively high learning curve. Keywords – Unikraft, Unikernels, Docker, Container / Syfte – Syftet med denna studie är att undersöka möjligheten att effektivisera lokala nätverk och databaser med hjälp av unikernels och att jämföra denna möjlighet med containrar. Detta kan även gälla utveckling av programvara för att säkerställa att programvaran exekveras på servern på exakt samma sätt som den tidigare gjort lokalt på utvecklarens lokala dator. Metod – Två experiment utförs för att undersöka om det går besvara syftet, kvantitativa data samlas in i båda fallen, datan är även redovisad kvantitativt. Python-script används föratt starta C-script som agerar klient och server. Tidtagning på algoritmer i unikernels respektive containrar samt minnesanvändning vid multipel instansiering mättes för att analyseras och jämföras. Resultat – Intermittenta svarstids-toppar gjorde datan från unikernels svår att korrekt utvärdera. Containrar hade ett lägre medelvärde på svarstider vid mindre krävande algoritm-användning. Unikernels medelvärde dyker under container-svarstiderna när mer krävande program simuleras. Några små buggar upptäcktesi Unikraft unikernels. Implikationer – Unikernels har egenskaper som gör de mer passande för vissa uppgifter jämfört med dess motsvarighet medan detsamma gäller för Containrar. Unikraft unikernels är instabila och ger därfören bild av att containrar vidmindre processorkrävande program faktiskt är snabbare än unikernels. Unikernels är bara snabbare och säkrare i den mån verktyget som bygger dem, gör det på ett sätt att de är stabila. Begränsningar – Avsaknaden av standarder, avsaknaden av ett communitysom kan svara på frågor tillsammans med att unikernelsär ett litet och nischat fält gör att unikernels har en relativ hög inlärningskurva. Nyckelord – Unikernel, Unikraft, Container, Docker