Multi-hop Wireless Networks (MWNs) represent a class of networks where messages are forwarded through multiple hops of wireless transmission. Applications of this newly emerging communication paradigm include asset monitoring wireless sensor networks (WSNs), command communication mobile ad hoc networks (MANETs), community- or campus-wide wireless mesh networks (WMNs), etc. Information security is one of the major barriers to the wide-scale deployment of MWNs but has received little attention so far. On the one hand, due to the open wireless channels and multi-hop wireless transmissions, MWNs are vulnerable to various information security threats such as eavesdropping, data injection/modification, node compromising, traffic analysis, and flow tracing. On the other hand, the characteristics of MWNs including the vulnerability of intermediate network nodes, multi-path packet forwarding, and limited computing capability and storage capacity make the existing information security schemes designed for the conventional wired networks or single-hop wireless networks unsuitable for MWNs. Therefore, newly designed schemes are highly desired to meet the stringent security and performance requirements for the information security of MWNs. In this research, we focus on three fundamental information security issues in MWNs: efficient privacy preservation for source anonymity, which is critical to the information security of MWNs; the traffic explosion issue, which targets at preventing denial of service (DoS) and enhancing system availability; and the cooperative peer-to-peer information exchange issue, which is critical to quickly achieve maximum data availability if the base station is temporarily unavailable or the service of the base station is intermittent. We have made the following three major contributions. Firstly, we identify the severe threats of traffic analysis/flow tracing attacks to the information security in network coding enabled MWNs. To prevent these attacks and achieve source anonymity in MWNs, we propose a network coding based privacy-preserving scheme. The unique “mixing” feature of network coding is exploited in the proposed scheme to confuse adversaries from conducting advanced privacy attacks, such as time correlation, size correlation, and message content correlation. With homomorphic encryption functions, the proposed scheme can achieve both privacy preservation and data confidentiality, which are two critical information security requirements. Secondly, to prevent traffic explosion and at the same time achieve source unobservability in MWNs, we propose a network coding based privacy-preserving scheme, called SUNC (Source Unobservability using Network Coding). Network coding is utilized in the scheme to automatically absorb dummy messages at intermediate network nodes, and thus, traffic explosion induced denial of service (DoS) can be naturally prevented to ensure the system availability. In addition to ensuring system availability and achieving source unobservability, SUNC can also thwart internal adversaries. Thirdly, to enhance the data availability when a base station is temporarily unavailable or the service of the base station is intermittent, we propose a cooperative peer-to-peer information exchange scheme based on network coding. The proposed scheme can quickly accomplish optimal information exchange in terms of throughput and transmission delay. For each research issue, detailed simulation results in terms of computational overhead, transmission efficiency, and communication overhead, are given to demonstrate the efficacy and efficiency of the proposed solutions.

Purpose - The purpose of this master thesis is to investigate the possibilities to extend or change the base of IKEA’s SL classification and give recommendations concerning potential improvements.  Method - This thesis has an inductive research strategy since data has been collected to build theory rather than the other way around (Bryman and Bell, 2007). The data has been collected by qualitative research, mainly through interviews with employees at the different IKEA organisations. Empirics - The empirical data gathered describes the service level in practice at IKEA. In order to get an overview of the conflicting interests in the different functions, the chapter is divided into four themes; how IKEA works with SL, the purpose of SL, customer service and suggestion to the design of the SL classification. Theory - The theory has been based on our empirical findings in order to find the best solution for IKEA. The theory includes different classification models, the relationship between customer service and SL and is finished with a section on how to measure availability. Conclusions - The conclusion that could be drawn was that the purpose of the classification was not perceived in the same way within the company and that both internal and external information is needed. A new model is presented that takes into account the different products, buying situations, and customer reactions on OOS, which are important parameters for consumer perception of availability and customer service. By using this model IKEA will be able to fulfil the two, sometimes conflicting purposes; to secure the sales and increase customer satisfaction.

Att ständigt vara tillgänglig och hantera inkommande e-post under en arbetsdag kan skapa upplevelse av stress. Syftet med studien var att se om skattningen av stressen minskade om en procedur som liknar traditionell postmottagning tillämpades. Studien genomfördes som ett experiment på en IT-avdelning. Deltagarna delades upp i en kontrollgrupp som arbetade som vanligt med sin e-post och en försöksgrupp som arbetade enligt instruktion. Studien pågick under 8 veckor och stressmätning genomfördes vid tre tillfällen, innan start av experimentet, efter 4 veckor och efter ytterligare 4 veckor. Resultatet visade att stresskattningen var högre för kvinnor medan männens stressupplevelse inte påverkades alls. Den ökade stresskattningen tog sig uttryck i en ökad takt i det egna beteendet, negativ känslomässig upplevelse i relation till andras beteende samt känslan av brist på inre kontroll. Utifrån resultatet är det angeläget att forska vidare på området så länge e-post förblir ett centralt arbetsverktyg. / To be readily accessible and constantly manage incoming e-mail in a working day can create perception of stress. The purpose of this study was to see if the perceived stress was reduced if a procedure similar to traditional mail handling was used. The study was conducted as an experiment in an IT department. Participants were divided into a control group who were working as usual with their e-mail and a test group that worked according to given instructions. The study lasted for 8 weeks and the stress was evaluated on three occasions, before the start of the experiment, after 4 weeks and at the end. The results showed that perceived stress level increased with women, while men's stress levels were not affected at all. The increased stress showed itself in an increased work pace, negative emotional experience in relation to the behavior of others and the feeling of a lack of internal control. Based on these results, it is certainty that further research in this area is needed as long as e-mail remains a key work tool.

Today rise in oil and gas demand, energy crisis, issues concerning energy security and increase in oil prices in the world provoke further exploration and production of oil and gas. The Arctic Sea is the last frontier of abundant hydrocarbon reserves. Having effective regulations, innovative technologies and adequate safety norms, the world has still seen some major accidents such as Gulf of Mexico accident. Knowing that offshore petroleum industry is moving further north in Arctic poses additional challenges due to harsh climatic conditions and remoteness from existing oil and gas infrastructure. The objective of this thesis is to provide an overview of offshore petroleum activity in arctic and sub-arctic areas as well as the accidents which took place in these areas. Furthermore, the accidents are analyzed with respect to the emergency preparedness handling of accidents using the NORSOK Z-013 standard as one basis. The thesis also discusses the anticipated emergency preparedness challenges for arctic and sub-arctic areas. The Arctic Sea is the final destination in the north having enormous amount of hydrocarbons. The harsh weather conditions of the Arctic Sea characterized by polar lows, long nights, extreme fog and sub-zero temperatures have not prevented the countries bordering the Arctic Sea in exploiting the oil and gas resources. Russia, having extended pipeline infrastructure, has the most active part in the Arctic region followed by the US and Norway. The offshore exploration and production activities in the Canadian and Greenland Arctic Sea are gradually progressing. Up to date, there have been very few accidents in the Arctic Sea thereby providing a limited knowledge base for emergency response in the Arctic Sea. The accidents which we have been able to account for are mainly related to blowout, pipeline leak, ship collision and capsize accidents. The accidents have occurred in the Russian Arctic Sea and the Alaskan Arctic Sea.The NORSOK Z-013 standard refers to alert, danger limitation, rescue, evacuation, and normalization as the five emergency preparedness phases and their detailed description is available in the Activities Regulation by the Petroleum Safety Authority in Norway (PSAN). It is stated in the NORSOK Z-013 standard that a set of Defined Situation of Hazard and Accident (DSHA) needs to be defined as part of the risk and emergency preparedness analysis. The set of DSHAs provided in the “Trends in risk level” project is used in this thesis for the classification and analysis of the accidents in the Arctic Sea.The analysis of the accidents in the Arctic Sea shows that all the emergency operations went through the phases of alert and normalization while the oil spill related accidents did not pass through escape and evacuate operations as there were no personnel involved in these accidents. All the emergency operations were affected by bad and tough weather conditions. Advanced emergency preparedness tools, equipment and technology are needed for effective emergency operations under such conditions. Due to scarcity of accidents in the Arctic Sea, only four DSHAs (out of 12) have been experienced, or at least reported. It may be that some of the remaining DSHAs are not reported due to minor consequences. In addition to the lessons learned from the emergency response operations for the accidents experienced in the Arctic Sea, there are also some emergency preparedness challenges which can be anticipated. The challenging weather conditions due to sudden polar lows, strong winds, spray icing, snowstorms and severe fog can hamper the emergency operations. Furthermore, long distances and lack of infrastructure can create communication and logistic problems and can result in delay of rescue and evacuation operations. Robust and reliable ice and weather data is a challenge due to global warming and may become a limiting factor for the adequate design of offshore equipment. The use and maintenance of emergency response equipment is also a challenge in sometimes dark, snowy and foggy areas of the Arctic Sea and the Barents Sea.

This thesis work focuses on designing a survivable IP-core network with the minimal investment of spare capacity. A span-oriented spare capacity allocation (SCA) scheme is proposed to satisfy customers' availability requirements in the end-to-end (E2E) sense. The novelty of the proposed SCA scheme is that it meets the E2E availability requirements despite the lack of knowledge of E2E bandwidth by employing protection rings covering all links in the network. Different ring selection methods are presented and also compared from the aspect of network redundancy and LP feasibility which provide more flexibility to the design. The proposed SCA algorithm further minimizes total cost of spare capacity by incorporating partial protection within the proposed architecture. The simulation results show that it can significantly reduce the spare capacity consumption depending on the availability. The proposed SCA scheme also performs better in terms of redundancy than that of two other dominant methods available these days.

Multi-hop Wireless Networks (MWNs) represent a class of networks where messages are forwarded through multiple hops of wireless transmission. Applications of this newly emerging communication paradigm include asset monitoring wireless sensor networks (WSNs), command communication mobile ad hoc networks (MANETs), community- or campus-wide wireless mesh networks (WMNs), etc. Information security is one of the major barriers to the wide-scale deployment of MWNs but has received little attention so far. On the one hand, due to the open wireless channels and multi-hop wireless transmissions, MWNs are vulnerable to various information security threats such as eavesdropping, data injection/modification, node compromising, traffic analysis, and flow tracing. On the other hand, the characteristics of MWNs including the vulnerability of intermediate network nodes, multi-path packet forwarding, and limited computing capability and storage capacity make the existing information security schemes designed for the conventional wired networks or single-hop wireless networks unsuitable for MWNs. Therefore, newly designed schemes are highly desired to meet the stringent security and performance requirements for the information security of MWNs. In this research, we focus on three fundamental information security issues in MWNs: efficient privacy preservation for source anonymity, which is critical to the information security of MWNs; the traffic explosion issue, which targets at preventing denial of service (DoS) and enhancing system availability; and the cooperative peer-to-peer information exchange issue, which is critical to quickly achieve maximum data availability if the base station is temporarily unavailable or the service of the base station is intermittent. We have made the following three major contributions. Firstly, we identify the severe threats of traffic analysis/flow tracing attacks to the information security in network coding enabled MWNs. To prevent these attacks and achieve source anonymity in MWNs, we propose a network coding based privacy-preserving scheme. The unique “mixing” feature of network coding is exploited in the proposed scheme to confuse adversaries from conducting advanced privacy attacks, such as time correlation, size correlation, and message content correlation. With homomorphic encryption functions, the proposed scheme can achieve both privacy preservation and data confidentiality, which are two critical information security requirements. Secondly, to prevent traffic explosion and at the same time achieve source unobservability in MWNs, we propose a network coding based privacy-preserving scheme, called SUNC (Source Unobservability using Network Coding). Network coding is utilized in the scheme to automatically absorb dummy messages at intermediate network nodes, and thus, traffic explosion induced denial of service (DoS) can be naturally prevented to ensure the system availability. In addition to ensuring system availability and achieving source unobservability, SUNC can also thwart internal adversaries. Thirdly, to enhance the data availability when a base station is temporarily unavailable or the service of the base station is intermittent, we propose a cooperative peer-to-peer information exchange scheme based on network coding. The proposed scheme can quickly accomplish optimal information exchange in terms of throughput and transmission delay. For each research issue, detailed simulation results in terms of computational overhead, transmission efficiency, and communication overhead, are given to demonstrate the efficacy and efficiency of the proposed solutions.

All organisms within a forested system play a role in the biogeochemical cycle, not only within the forest but also within the global community. Soil microorganisms are a vital part of this cycle, as they sequester or make nutrients available for the development of the forest environment. When a disturbance event occurs, changes to the environment occur; however, it is unclear how these changes affect the soils microbial community. This 2-year (2007 and 2008) study was carried out to obtain a preliminary assessment of the microbial community structure and nutrient (nitrogen and phosphorus) availability within lodgepole pine stands of the Boreal Plain ecozone in west-central Alberta. Six stands of different ages were selected to determine the differences between pre and post harvest. Nutrient flux measurements were conducted using plant root simulator (PRS) probes to investigate the changes in nutrient availability. The microbial community structures were determined using two biochemical methods. The first one was a community level physiological profile (CLPP), which provides information concerning the functional characteristics of the microbial communities. Phospholipid fatty acid (PLFA) analysis provides information about the physiological characteristics of the microbial community. Analysis of the PRS probes results varied for the two nutrients: phosphorus (P) and nitrogen (N). Nitrogen availability was determined by examining the fluxes of ammonium and nitrate to the PRS probes. These did not show a strong relationship between the different aged stands during 2007 or 2008. In addition, no statistical difference was shown between the 2007 and 2008 data compared to the LFH or the mineral soil of the stands. Phosphorus, however, did show a potential trend where there was an initial increase of available P after harvest and then a gradual decrease, as the forest stands matured. This was strongly observed within the LFH, while there was a slight increase in the mineral layer. These trends remained consistent over the two-year period showing a gradual decrease in P flux to the PRS probes as a stand aged even in just one year. The microbial communities did not show a strong change after a forest-harvesting event. When examining the functional groups, there was a drastic shift in the LFH layer microbial community over the first sampling season. This change remained the same within the beginning of the second sampling year. This shift occurred in all stands due to an environmental factor, which was suspected to be the increase in moisture during the season. The change in the microbial communities was not observed, however, in the mineral layer of the soil when the functional structure was examined. When the physiological composition of the microbial communities was observed, though, using PLFA, it was apparent that the physiological characteristics of the microbial community had changed in the mineral soil. Furthermore, no physiological change was observed in the microbial communities of the LFH, only a functional change.

This dissertation focuses on developing inspection schedules to detect non-self- announcing events which can only detected by inspections. Failures of protective sys- tems ,such as electronic equipments, alarms and stand-by systems, incipient failures and the emergence of certain medical diseases are examples of such events. Inspec- tions are performed at pre-determined times to detect whether or not the event has occurred, and necessary actions are taken upon the detection. In this research, my interest is in developing effective inspection schedules to detect non-self-announcing events that balance system downtime and inspection effort. To evaluate the quality of an inspection schedule, I use the availability (for re- placeable) and the detection delay (for non-replaceable systems) as performance mea- sures. When the monetary cost of inspection and the cost of delay are difficult to determine, non-monetary performance measures become more meaningful. In this research, the focus is on maximizing availability or minimizing detection delay given a limited number of inspections or a limited inspection rate. I show that for replace- able and non-replaceable systems, it is possible to construct inspection schedules that perform better than periodic inspection with respect to our performance measures. The occurrence of the event I would like to detect may be influenced by certain individual characteristics. For instance, the risk of developing a certain type of dis- ease might be different for different subgroups within the population. In this case, because of the non-homogeneity in the population, benefits of performing screening tests may not be fully achieved for each sub-group by using an inspection strategy developed for the entire population. Thus, it may be of value for an individual to learn more information about his/her likehood to have the disease. To address this issue, I analyze the change in the expected delay if schedules are based on the whole population information or the individual information and provide numerical results.

This study was directed at examining the effects of exhaust gas recirculation (EGR), water/N2/CO2 injections and oxygen enrichment on availability destroyed because of combustion in simple systems like those of constant pressure and constant volume. Higher cooled EGR fractions lead to higher availability destruction for reactant temperatures less than 2000 K. The availability destroyed for 40% EGR at 300 K for constant pressure and constant volume combustion was 36% and 33%, respectively. Neglecting the chemical availability in the products, the equivalence ratio and reactant temperature that corresponded to the lowest availability destruction varied from 0.8 to 1.0 and 800 K to 1300 K, respectively, depending on the EGR fraction. The fraction of the reactant availability destroyed increased with the complexity of the fuel. The trends stayed the same for the different EGR fractions for the eight fuels that were analyzed. Higher injected water fractions lead to higher availability destruction for reactant temperatures less than 1000 K. The availability destroyed for a 40% injected water fraction at 300 K for constant pressure combustion was 36%. The product temperature ranged from 2300 K to 450 K at a reactant temperature of 300 K for injected fractions from 0% to 90%. For a 40% injected fraction at a reactant temperature of 300 K, water injection and cooled EGR resulted in the greatest destruction of availability (about 36%) with CO2 injection leading to the least destruction (about 32%). Constant volume combustion destroyed less availability compared to constant pressure combustion at a reactant pressure of 50 kPa. At a higher reactant pressure of 5000 kPa, constant pressure combustion destroyed less availability compared to constant volume combustion for reactant temperatures past 1000 K. Higher fractions of oxygen in the inlet lead to higher product temperatures that lead to lower availability destruction. For 40% oxygen in inlet, the product temperature increased to 2900 K and the availability destroyed dropped to 25% at a reactant temperature of 300 K for constant pressure combustion.

Water availability has been of great concern in the State of Texas and many other places worldwide. During 1997-2003, pursuant to the 1997 Senate Bill 1, the Texas Commission on Environmental Quality (TCEQ), its partner agencies, and contractors developed a Water Availability Modeling (WAM) System based on the Water Rights Analysis Package (WRAP) model, developed at Texas A&M University. WAM has been widely applied in the State of Texas and because of its convenience, applications, and capabilities, it is planned to be implemented in other States and Countries. This thesis addresses different aspects of WAM, including conditional reliability modeling, firm yield analysis following classic and recently developed methodologies, evaluating the impact of different considerations on reliability analyses, simplification of complex WAM datasets and the display of WRAP results into ArcMap. Conditional reliability modeling evaluates short term diversion/storage reliabilities based on an initial storage level. WRAP-CON has been evaluated and improved, in addition a new modeling methodology has been developed, in which probabilities of occurrence for each hydrologic sequence is based on the relationship between storage and future flows. Recently developed WRAP capabilities have been evaluated, providing users new tools and increased flexibility. Some of these improvements are firm yield analysis, cycling and dual simulation. In addition to improved software, guidelines have also been developed, including a set to simplify extremely large WAM datasets, while maintaining the effect of all the other water rights in a basin.