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Resilience engineering first appeared as a new approach for both system design and system safety in the last decade. One of the first substantive publications on resilience as applied to engineering was Resilience Engineering: Concepts and Precepts [Hollnagel et al. 2006]. Hollnagel, Woods, and Leveson developed the basic concepts behind resilience engineering in order to understand and prevent tragedies such as the Columbia Challenger accident and the September 11 terrorist attack.<p> In its present stage, resilience engineering has several fundamental problems. 1. There is not an appropriate definition for resilience. 2. The differences between resilience and other similar concepts are not clarified. 3. There is no quantitative method which can measure resilience. The three questions need to be addressed in order to advance the concept of resilience engineering and form a theoretical concept to an applied science. These three issues then form the foundation of this thesis.<p> As a first step, a resilience definition is presented based on the concepts of system function and damage. Then, the differences between resilience and five similar concepts (reliability, robustness, repairing, redundancy, and sustainability) are clearly elaborated. As a last step, a method for quantifying resilience is proposed in the form of a resilience index. This method exclusively measures system resilience by analyzing the system recoverability from two points of view: reconfiguration and replacement of components.<p> In order to illustrate the approach to and definitions of resilience, an actual application is considered: a water pumping station operated by SaskWater in Saskatoon, Saskatchewan (the Clarence Booster Station). This pumping station is a complicated system consisting of mechanical electrical and chemical subsystems. The resilience of Clarence Booster Station is analyzed using the proposed definition of resilience and resilience index.<p> This thesis is just an initial step establishing a comprehensive definition (qualitatively and quantitatively) for resilience. The resilience index so defined in this work appears to have potential but much more scrutiny and refinement must be pursued to ensure that it is truly applicable to more universal engineering applications.

Intensive swine operations produce large amounts of manure that must be dealt with responsibly. Liquid swine manure (LSM) collected in storage units is applied to cropland as a nutrient source. Maximizing crop utilization of the nitrogen (N) added in manure is important to achieve economic and environmental benefits. The objectives of this research were to evaluate the effect of 1) adding a nitrification inhibitor and 2) using supplemental phosphorus (P) and sulfur (S) fertilizers as means of enhancing crop recovery of LSM-N.<p>Field experiments were conducted at two long-term manure management sites in Saskatchewan; 1) Dixon (Black Chernozem) and 2) Melfort (Dark Grey Luvisol). At the Dixon site, plant and soil samples were collected throughout the 2005 and 2006 growing season, and ammonium-N (NH4+-N) and nitrate-N (NO3--N) concentration in soil, and total N content in plant were measured. Plant root simulator (PRSTM) probes were used to measure NH4+-N and NO3--N supply rates at the Dixon site to determine the effectiveness of a nitrification inhibitor dicyandiamide (DCD) added to LSM. Crop recovery of N applied through LSM application was assessed by measuring seed and straw yield and total N content. The effect of adding supplemental P fertilizer at 6.5 kg P ha-1 to swine manure amended soil on N recovery was also evaluated at the Dixon site. At the S deficient Melfort site, the effect of supplemental S fertilizer added at 40 kg S ha-1 as ammonium sulfate and elemental S was evaluated.<p>The addition of DCD (0.275 mL kg-1) to LSM in 2005 and 2006 at Dixon did not significantly affect the proportion of LSM-N recovered or the seed yield. However, measurements of available NH4+-N and NO3--N concentrations and supply rates at the beginning of the growing season in 2005 indicated that the nitrification inhibitor was effective in keeping more of the LSM-N in the NH4+ form for approximately 14 days after LSM application. <p> The addition of supplemental P fertilizer to plots fertilized with LSM at the Dixon site, generally did not produce any significant increase in crop N recovery or seed yield. However, increase in crop N recovery and seed yield in 100 kg N ha-1 urea treatments indicates that there was insufficient P available in the soils to maximize crop N recovery and seed yield. It appears that LSM is able to provide sufficient amounts of available P when applied annually at rates of 37,000 L ha-1 or higher. <p>At the Melfort site, the addition of supplemental S fertilizer did not significantly affect crop N recovery or seed yield in LSM treatments. Annual applications of the low rate of LSM of 37,000 L ha-1 supplied sufficient amounts of N and S to maximize seed yield and crop N recovery. However, large significant increases in seed yield and crop N recovery with supplemental S fertilizers were observed in the 80 kg N ha-1 urea treatment.<p>The use of a nitrification inhibitor added to LSM was effective at maintaining N in NH4+ form longer; however there was no significant effect on final yield, grain N or %N recovery. This may be due to the low N loss potential on prairies. Supplemental S and P fertilizer may be required with liquid swine manure. Supplemental commercial fertilizers with LSM are dependant on: the crop nutrient requirements, soil nutrient status and manure nutrient composition.

Web applications store their data at the server. Despite several benefits, this design raises a serious problem because a bug or misconfiguration causing data loss or corruption can affect a large number of users. We describe the design of a generic recovery system for web applications. Our system tracks application requests and reuses undo logs already kept by databases to selectively recover from corrupting requests and their effects. The main challenge is to correlate requests across the multiple tiers of the application to determine the correct recovery actions. We explore using dependencies both within and across requests at three layers, (i.e., database, application, client) to help identify data corruption accurately. We evaluate our system using known bugs and misconfigurations in popular web applications, including Wordpress, Drupal and Gallery2. Our results show that our system enables recovery from data corruption without loss of critical data incurring little overhead while tracking requests.

The purpose of the present research was to examine and understand, within a cultural context, the subjective experiences of recovery from child abuse of adults who have not sought the help of mental health professionals. Examining the cultural context of recovery permitted a glance at the environmental climate in which people came to understand, respond, and make sense of their child abuse experiences. To achieve this objective, dominant themes regarding beliefs about recovery were gathered from cultural documents, specifically, popular books on recovery from abuse, and from individual accounts of recovery from abuse. The present study was qualitative in nature and conducted within the framework of an ethnographic inquiry. The data were content analysed for themes of recovery. A comparison of recovery themes in popular books and participant interviews revealed that participants descriptions of their recovery mirrored those described by popular books, with a few exceptions. Factors considered helpful for recovery which emerged from both sources included education/information, relationships (e.g., support and resolution), attending to ones feelings and beliefs about the abuse (e.g, re-experiencing), self-care (e.g., coping with stress), and spirituality. In both popular books and participant stories, value was placed on the survivor looking inward, and differentiating oneself, ones feelings and beliefs, from those of others. This orientation served to delineate clear boundaries from others, and to allow one to assert oneself and to develop an independent view of oneself (Markus & Kitayama, 1991). As such, it reflects Canadian/American cultural values of agency, autonomy, and personal control (Kirsh & Kuiper, 2002). The participants experiences of recovery enabled them to reconstruct their views of themselves, their abusers, and people in general, in a way that enabled them to assert their differences and distinct values from others. Although support was emphasized, its role was confined to helping the participants gain new understanding of their experiences. Their disclosures of abuse experiences to supportive others were guided less by the need to create harmony or to fit in with an in-group, as would be expected in collectivist societies, than it was by the need to assert oneself, ones feelings, and ones needs. Also, participants accounts of recovery illustrated that they were relatively well versed in the use of psychological terms and concepts such as grief, confrontation, self-esteem, and role-models that were common in the popular books. The participants developed new views of themselves which were geared toward developing a more self-enhancing sense of self. These shifts reflect a discourse common in psychology and self-help culture, which directs the individual toward self-actualization, heightened self-esteem, and increased autonomy (Starker, 1989). This study also demonstrated how, through their own personal resourcefulness, people can be agents of their own recovery. Participants accessed unique resources (e.g., participating in sports, parenting, religion) to make sense of their experiences. In some cases, participants focussed more on drawing meaning from these self-enhancing resources than they did on re-experiencing painful memories associated with the abuse. Given the emphasis on re-experiencing trauma in clinical and popular literature, the various routes taken by participants suggest that the process of re-experiencing may be over-emphasized. Further research on recovery, outside of the therapeutic context, may serve to clarify how self-recovery takes place, possibly contributing to a new discourse on recovery.

Digital resampling is a process that converts a digital signal from one sampling rate to another. This process is performed by means of interpolating between the input samples to produce output samples at an output sampling rate. The digital interpolation process is accomplished with an interpolation filter.<p> The problem of resampling digital signals at an output sampling rate that is incommensurate with the input sampling rate is the first topic of this thesis. This problem is often encountered in practice, for example in multiplexing video signals from different sources for the purpose of distribution. There are basically two approaches to resample the signals. Both approaches are thoroughly described and practical circuits for hardware implementation are provided. A comparison of the two circuits shows that one circuit requires a division to compute the new sampling times. This time scaling operation adds complexity to the implementation with no performance advantage over the other circuit, and makes the 'division free' circuit the preferred one for resampling.<p> The second topic of this thesis is performance analysis of interpolation filters for Quadrature Amplitude Modulation (QAM) signals in the context of timing recovery. The performance criterion of interest is Modulation Error Ratio (MER), which is considered to be a very useful indicator of the quality of modulated signals in QAM systems. The methodology of digital resampling in hardware is employed to describe timing recovery circuits and propose an approach to evaluate the performance of interpolation filters. A MER performance analysis circuit is then devised. The circuit is simulated with MATLAB/Simulink as well as implemented in Field Programmable Gate Array (FPGA). Excellent agreement between results obtained from simulation and hardware implementation proves the validity of the methodology and practical application of the research works.

Because of the high demand for hydrogen in the oil industries, new technologies for hydrogen production are being investigated. The thermochemical splitting cycle is one of them. Among the cycles that have been investigated, sulfur-iodine (S-I) water splitting is the most studied. In the S-I cycle, there are three reactions: H2SO4 decomposition, Bunsen reaction and HI decomposition. A new thermochemical cycle has been developed based on the S-I cycle, which is a H2S splitting cycle. In the H2S cycle, there are also three reactions. The only difference between S-I and H2S cycle is that the H2SO4 decomposition reaction is replaced by a reaction between hydrogen sulfide and sulfuric acid which produces sulfur dioxide, elemental sulfur and water. Research on this reaction has been done for many years, studying thermodynamic, kinetics and mass transfer. This reaction produces sulfur, sulfur dioxide and water. The SO2 produced is the used in the second reaction in the H2S cycle; the Bunsen reaction.<p> The main objective of this research was to find an operating condition to increase the production of SO2 from the reaction between H2S and H2SO4. This study investigated different conditions such as temperature, stirring rate and sulfuric acid concentration to maximize the production of SO2. The temperature and stirring rate range used in the reaction were from 120 to 160°C and from 0 to 400 rpm, respectively. The sulfuric acid concentrations were between 90 and 96 wt%. The results showed that increasing the temperature and the acid concentration in the reaction between H2S and H2SO4, the SO2 produced from this reaction will increase. There is no need to apply stirring in the reaction, because the stirring will increase the surface area which allows the produced sulfur dioxide in the gas phase to be dissolved more in sulfuric acid solution, which favors the unwanted side-reaction between SO2 and H2S. A model that was developed to predict the partial pressure change of SO2 in closed reactor. This model was used to compare the data between experimental and simulation through Matlab software. The simulated data was compared to the experimental data and the results indicated that the model fits the data satisfactorily. Additionally, study on the separation between the remaining sulfuric acid and produced elemental sulfur from the reaction between H2S and H2SO4 were performed. The mixture was placed in an oven at140°C of temperature for two hours. It was found that all small droplets of sulfur produced during the reaction between hydrogen sulfide and sulfuric acid agglomerated and the sulfuric acid solution became clearer.

The purpose of the present research was to examine and understand, within a cultural context, the subjective experiences of recovery from child abuse of adults who have not sought the help of mental health professionals. Examining the cultural context of recovery permitted a glance at the environmental climate in which people came to understand, respond, and make sense of their child abuse experiences. To achieve this objective, dominant themes regarding beliefs about recovery were gathered from cultural documents, specifically, popular books on recovery from abuse, and from individual accounts of recovery from abuse. The present study was qualitative in nature and conducted within the framework of an ethnographic inquiry. The data were content analysed for themes of recovery. A comparison of recovery themes in popular books and participant interviews revealed that participants descriptions of their recovery mirrored those described by popular books, with a few exceptions. Factors considered helpful for recovery which emerged from both sources included education/information, relationships (e.g., support and resolution), attending to ones feelings and beliefs about the abuse (e.g, re-experiencing), self-care (e.g., coping with stress), and spirituality. In both popular books and participant stories, value was placed on the survivor looking inward, and differentiating oneself, ones feelings and beliefs, from those of others. This orientation served to delineate clear boundaries from others, and to allow one to assert oneself and to develop an independent view of oneself (Markus & Kitayama, 1991). As such, it reflects Canadian/American cultural values of agency, autonomy, and personal control (Kirsh & Kuiper, 2002). The participants experiences of recovery enabled them to reconstruct their views of themselves, their abusers, and people in general, in a way that enabled them to assert their differences and distinct values from others. Although support was emphasized, its role was confined to helping the participants gain new understanding of their experiences. Their disclosures of abuse experiences to supportive others were guided less by the need to create harmony or to fit in with an in-group, as would be expected in collectivist societies, than it was by the need to assert oneself, ones feelings, and ones needs. Also, participants accounts of recovery illustrated that they were relatively well versed in the use of psychological terms and concepts such as grief, confrontation, self-esteem, and role-models that were common in the popular books. The participants developed new views of themselves which were geared toward developing a more self-enhancing sense of self. These shifts reflect a discourse common in psychology and self-help culture, which directs the individual toward self-actualization, heightened self-esteem, and increased autonomy (Starker, 1989). This study also demonstrated how, through their own personal resourcefulness, people can be agents of their own recovery. Participants accessed unique resources (e.g., participating in sports, parenting, religion) to make sense of their experiences. In some cases, participants focussed more on drawing meaning from these self-enhancing resources than they did on re-experiencing painful memories associated with the abuse. Given the emphasis on re-experiencing trauma in clinical and popular literature, the various routes taken by participants suggest that the process of re-experiencing may be over-emphasized. Further research on recovery, outside of the therapeutic context, may serve to clarify how self-recovery takes place, possibly contributing to a new discourse on recovery.

Web applications store their data at the server. Despite several benefits, this design raises a serious problem because a bug or misconfiguration causing data loss or corruption can affect a large number of users. We describe the design of a generic recovery system for web applications. Our system tracks application requests and reuses undo logs already kept by databases to selectively recover from corrupting requests and their effects. The main challenge is to correlate requests across the multiple tiers of the application to determine the correct recovery actions. We explore using dependencies both within and across requests at three layers, (i.e., database, application, client) to help identify data corruption accurately. We evaluate our system using known bugs and misconfigurations in popular web applications, including Wordpress, Drupal and Gallery2. Our results show that our system enables recovery from data corruption without loss of critical data incurring little overhead while tracking requests.

Carryover particles are partially/completely burned black liquor particles entrained in the flue gas in kraft recovery boilers. Understanding how carryover particles form and deposit on heat transfer tube surfaces is critically important in the design and operation of a recovery boiler. The tendency for a carryover particle to deposit on a tube surface depends on the particle temperature and composition at the moment of impact. This study was the first to examine systematically how carryover particle composition changes with the black liquor chemistry and burning conditions. The effect of black liquor composition and particle size, gas composition (O2 and SO2 concentrations) and temperature on the composition of carryover particles were studied using an Entrained Flow Reactor (EFR). Field studies were conducted on three operating boilers, where an air-cooled probe was used to collect carryover samples at the superheater entrance. The results show that the chloride (Cl) and potassium (K) contents in carryover particles were linearly proportional to their contents in black liquor. Cl and K were depleted during black liquor combustion due mainly to the vaporization of NaCl and KCl. The depletion of Cl is about three times greater than that of K. The significant depletion of Cl implies that carryover particles contain much less Cl, and hence, are less sticky than previously expected from black liquor composition. A dynamic model was also developed to predict the composition of carryover particles as a function of black liquor composition and burning conditions. Based on the data obtained experimentally in this study, the kinetic equations for the oxidation of sulphide available in the literature were modified and incorporated into the model to improve its sulphide and sulphate predictions. The model predicts the main components of carryover particles formed in both the EFR and three operating recovery boilers reasonably well, except for the K content, which is slightly over-predicted at high O2 concentrations (or high particle temperatures). Based on the predicted composition, it is possible to determine the thermal properties of carryover and to assess its fouling propensity in the boiler. The information helps boiler manufacturers and operators to identify locations in the boiler where massive carryover deposition may occur and to devise appropriate control strategies to minimize fouling and to improve boiler thermal efficiency.