The method of magnetotellurics (MT) uses surface measurements of naturally-occurring electromagnetic fields to investigate the conductivity distribution within the Earth. In many interpretations it is adequate to represent the conductivity structure by a one-dimensional (1-D) model. Inferring information about this model from surface field measurements is a non-linear inverse problem. In this thesis, linearized construction and appraisal algorithms are developed for the 1-D MT inverse problem. To formulate a linearized approach, the forward operator is expanded in a generalized Taylor series and second-order terms are neglected. The resulting linear problem may be solved using techniques of linear inverse theory. Since higher-order terms are neglected, the linear problem is only approximate, and this process is repeated iteratively until an acceptable model is achieved. Linearized methods have the advantage that, with an appropriate transformation, a solution may be found which minimizes a particular functional of the model known as a model norm. By explicitly minimizing the model norm at each iteration, it is hypothesized that the final constructed model represents the global minimum of this functional; however, in practice, it is difficult to verify that a global (rather than local) minimum has been found. The linearization of the MT problem is considered in detail in this thesis by deriving complete expansions in terms of Fréchet differential series for several choices of response functional, and verifying that the responses are indeed Fréchet differentiable. The relative linearity of these responses is quantified by examining the ratio of non-linear to linear terms in order to determine the best choice for a linearized approach. In addition, the similitude equation for MT is considered as an alternative formulation to linearization and found to be inadequate in that it implicitly neglects first-order terms. Appropriate choices of the model norm allow linearized inversion algorithms to be formulated which minimize a measure of the model structure or of the deviation from a (known) base model. These inversions construct the minimum-structure and smallest-deviatoric model, respectively. In addition, minimizing I₂ model norms lead to smooth solutions which represent structure in terms of continuous gradients, whereas minimizing I₁ norms yield layered conductivity models with structural variations occurring discontinuously. These two formulations offer complementary representations of the Earth, and in practice, a complete interpretation should consider both. The algorithms developed here consider the model to be either conductivity or log conductivity, include an arbitrary weighting function in the model norm, and fit the data to a specified level of misfit: this provides considerable flexibility in constructing 1-D models from MT responses. Linearized inversions may also be formulated to construct extremal models which minimize or maximize localized conductivity averages of the model. These extremal models provide bounds for the average conductivity over the region of interest, and thus may be used to appraise model features. An efficient, robust appraisal algorithm has been developed using linear programming to extremize the conductivity averages. For optimal results, the extremal models must be geophysically reasonable, and bounding the total variation in order to limit unrealistic structure is an important constraint. Since the extremal models are constructed via linearized inversion, the possibility always exists that the computed bounds represent local rather than global extrema. In order to corroborate the results, extremal models are also computed using simulated annealing optimization. Simulated annealing makes no approximations and is well known for its inherent ability to avoid unfavourable local minima. Although the method is considerably slower than linearized analysis, it represents a general and interesting new appraisal technique. The construction and appraisal methods developed here are illustrated using synthetic test cases and MT field data collected as part of the LITHOPROBE project. In addition, the model construction techniques are used to analyze MT responses measured at a number of sites on Vancouver Island, Canada, to investigate the monitoring of local changes in conductivity as a precursor for earthquakes. MT responses measured at the same site over a period of four years are analyzed and indicate no significant changes in the conductivity (no earthquakes of magnitude greater than 3.0 occurred in this period). Conductivity profiles at a number of sites are also considered in an attempt to infer the regional structure. Finally, a method of correcting linearized inversions is developed. The corrections consist of successively approximating an analytic expression for the linearization error. The method would seem to represent a novel and practical approach that can significantly reduce the number of linearized iterations. In addition, a correspondence between the correction steps and iterations of the modified Newton's method for operators is established. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Autonomous Unmanned Aerial Vehicles (UAVs) in agriculture are increasingly in demand to reduce cost, labour and increase effectiveness and quality in farming. However, it is necessary to improve reliability for this technology to perform its full potential without harming humans, animals or the environment. The reliability increases by identifying the hazards and mitigating them. Therefore the risks are identified, analyzed and mitigated using analysis tools. Two different methods are used to analyze and reduce hazards, and each method utilizes various analysis tools. In addition, redundancy and preventive action are proposed to eliminate or minimize the danger. This thesis identifies risks by studying and reviewing a generic use-case from the AFarCloud project and compares the two hazard analysis methods to determine which method provides the most reliable result.

Deep wastewater injection-induced seismicity has led to over a thousand magnitude (Mw) > 3 earthquakes and four Mw>5 earthquakes in Oklahoma, Texas, and Kansas (OTK) over the last ten years. Liquefaction observed following the 3 September 2016, Mw5.8 Pawnee, OK, induced earthquake raises concerns regarding the liquefaction risk posed by future induced earthquakes. The stress-based simplified liquefaction evaluation procedure is widely used to evaluate liquefaction potential. However, empirical aspects of this procedure were primarily developed for tectonic earthquakes in active shallow-crustal tectonic regimes (e.g., California). Consequently, due to differences in ground motion characteristics and regional geology, the depth-stress reduction factor (rd) and Magnitude Scaling Factor (MSF) relationships used in these variants may be unsuitable for use with induced earthquakes in OTK. This is because both rd, which accounts for the non-rigid soil profile response, and MSF, which accounts for shaking duration, are affected by ground motion and soil profile characteristics. The objective of this research is to develop and test a new liquefaction triggering model for use in assessing the regional liquefaction hazard in OTK from injection-induced earthquakes. This model incorporates induced seismicity-specific rd and MSF relationships. To assess model efficacy, the liquefaction potential is evaluated for several sites impacted by the 2016 Pawnee earthquake using the model developed herein, as well as several models commonly used to evaluate liquefaction potential for tectonic earthquakes. Estimates are then compared with field observations of liquefaction made following the Pawnee event. This analysis shows that, at most sites, the induced seismicity-specific model more accurately predicts liquefaction severity than do models developed for tectonic earthquakes, which tend to over-predict liquefaction severity. The liquefaction triggering model developed herein is also used to assess the minimum magnitude (Mmin) of induced earthquakes capable of triggering liquefaction. For sites capable of supporting structures, it is shown that Mmin = 5.0 is sufficient to fully capture liquefaction hazard from induced events in OTK. However, for extremely liquefaction-susceptible soil profiles that are potentially relevant to other infrastructure (e.g., pipelines and levees), consideration of Mmin as low as 4.0 may be required. / Doctor of Philosophy / Seismic activity caused by deep wastewater injection has caused over a thousand magnitude (Mw) > 3 earthquakes and four Mw>5 earthquakes in Oklahoma, Texas, and Kansas (OTK) over the last ten years. These events are referred to as induced earthquakes. Liquefaction observed following the 3 September 2016, Mw5.8 Pawnee, OK, induced earthquake raises concerns regarding the liquefaction risk posed by future induced earthquakes. The stress-based simplified liquefaction evaluation procedure is widely used to evaluate liquefaction potential. However, to date, variants of this procedure were developed primarily for natural, tectonic earthquakes in active seismic areas such as California. Due to differences between induced and tectonic earthquakes as well as regional geology, existing variants of the simplified procedure may be unsuitable for use with induced earthquakes in OTK. The objective of this research is to develop and test a new liquefaction triggering model for use in assessing the regional liquefaction hazard in OTK from injection-induced earthquakes. The model was developed using regional induced earthquake ground motion recordings and soil profiles. To assess model accuracy, liquefaction potential is assessed at several sites impacted by the 2016 Pawnee earthquake using the new model, as well as several models commonly used to evaluate liquefaction potential for tectonic earthquakes. Estimates are then compared with field observations of liquefaction made following the Pawnee event. This analysis shows that, at most sites, the induced seismicity-specific model more accurately predicts liquefaction severity than do models developed for tectonic earthquakes, which tend to over-predict liquefaction severity. The liquefaction triggering model developed herein is used to assess the minimum magnitude (Mmin) of induced earthquakes capable of triggering liquefaction. For sites capable of supporting structures, it is shown that Mmin = 5.0 is sufficient to fully capture liquefaction hazard from induced events in OTK. However, for extremely liquefaction-susceptible soil profiles potentially relevant to other infrastructure (e.g., pipelines and levees), Mmin as low as 4.0 may be required.

Yes / Bioarchaeological and clinical data show that diet influences health, and this relationship is crucial to how we understand past health with respect to sex and age. We propose a new method that coinvestigates the relationship between mortality risk and diet in the past. Our method integrates dietary stable isotope data (δ13 Carbon and δ 15 Nitrogen) from Roman Britain (N=659) with hazards analysis. The results show that these data can be informatively used in this type of analysis in general, and that in the context of Roman Britain, higher δ 13C is associated with lower risks of mortality while higher δ 15N is associated with elevated risks of mortality. Importantly, the results emphasize that a bioarchaeological approach to interpretation must be taken in order to more fully understand the results obtained by the method

by Wong, Tak-yee Tammy. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 170-178). / ABSTRACT --- p.i-iii / ACKNOWLEDGEMENTS --- p.iv-v / TABLE OF CONTENTS --- p.vi-x / LIST OF FIGURES --- p.xi-xii - / LIST OF PLATES --- p.xiii-ix / LIST OF TABLES --- p.x-xii / Chapter CHAPTER I: --- INTRODUCTION --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Research Questions --- p.5 / Chapter 1.3 --- Study Significance --- p.7 / Chapter 1.4 --- Organization of the Thesis --- p.8 / Chapter CHAPTER II: --- LITERATURE REVIEW --- p.10 / Chapter 2.1 --- Introduction --- p.10 / Chapter 2.2 --- Nature of Landslides --- p.10 / Chapter 2.2.1 --- Landslide Classification --- p.10 / Chapter 2.2.2 --- Morphometry of Landslides --- p.12 / Chapter 2.2.3 --- Factors Affecting Landslide Occurrence --- p.16 / Chapter 2.2.3.1 --- Gradient --- p.19 / Chapter 2.2.3.2 --- Slope Shape --- p.21 / Chapter 2.2.3.3 --- Aspect --- p.22 / Chapter 2.2.3.4 --- Vegetation --- p.24 / Chapter 2.2.3.5 --- Drainage --- p.26 / Chapter 2.2.3.6 --- Precipitation/Seismicity --- p.26 / Chapter 2.2.3.7 --- Lithology and Geological Influences --- p.28 / Chapter 2.2.3.8 --- Regolith --- p.29 / Chapter 2.2.3.8.1 --- Hydrological Properties of Soils --- p.29 / Chapter 2.2.3.8.2 --- Engineering Properties of Soils --- p.30 / Chapter 2.3 --- Data Sources for Landslide Studies --- p.31 / Chapter 2.3.1 --- Aerial Photo Interpretation (API) --- p.32 / Chapter 2.3.2 --- Remote Sensing --- p.34 / Chapter 2.3.3 --- Field Survey --- p.35 / Chapter 2.3.4 --- Subsurface Investigation --- p.36 / Chapter 2.4 --- Landslide Studies in Hong Kong --- p.36 / Chapter 2.5 --- Applications of GIS on Landslide Studies --- p.38 / Chapter 2.5.1 --- Major Data in GIS for Landslide Studies --- p.39 / Chapter 2.5.1.1 --- Triangulated Irregular Network (TIN) as a Representation of Surface --- p.39 / Chapter 2.5.2 --- Applications --- p.42 / Chapter 2.5.2.1 --- Inventory --- p.43 / Chapter 2.5.2.2 --- Landslide Hazard Assessment --- p.43 / Chapter 2.5.2.2.1 --- Statistical Modeling --- p.46 / Chapter 2.5.2.2.2 --- Physical Processes or Three- Dimensional Modeling --- p.50 / Chapter 2.6 --- Suggestions for Future Research Directions --- p.51 / Chapter CHAPTER III: --- STUDY AREA --- p.54 / Chapter 3.1 --- Location and Choice of Study Area --- p.54 / Chapter 3.2 --- Climatic Aspects --- p.56 / Chapter 3.3 --- Geological Aspects --- p.62 / Chapter 3.3.1 --- General Information of GASP V --- p.62 / Chapter 3.3.2 --- Rock Types Specific to the Two Sites Chosen --- p.63 / Chapter 3.3.2.1 --- Volcanic Units - Repulse Bay Formation --- p.65 / Chapter 3.3.2.2 --- Sedimentary Units - Port Island Formation (PI) --- p.65 / Chapter 3.4 --- Geomorphological Aspects --- p.66 / Chapter 3.4.1 --- General Information of GASP V --- p.66 / Chapter 3.5 --- Erosion and Stability --- p.67 / Chapter 3.6 --- Vegetation --- p.67 / Chapter 3.7 --- Summary --- p.70 / Chapter CHAPTER IV: --- DATABASE CONSTRUCTION AND MANIPULATION --- p.71 / Chapter 4.1 --- Data Collection --- p.73 / Chapter 4.1.1 --- Aerial Photo Interpretation (API) --- p.73 / Chapter 4.1.1.1 --- Landslip Inventory --- p.75 / Chapter 4.1.2 --- Field Techniques --- p.78 / Chapter 4.1.2.1 --- Slope Failure/Deposit Field Survey sheet --- p.78 / Chapter 4.1.2.2 --- Collection of Landslide Data --- p.79 / Chapter 4.1.3 --- Collection of Existing Data --- p.80 / Chapter 4.1.3.1 --- 1:5000 Topographic Maps --- p.80 / Chapter 4.1.3.2 --- Terrain Classification --- p.81 / Chapter 4.1.3.3 --- WWF Vegetation Database --- p.85 / Chapter 4.2 --- Data Input and Conversion --- p.86 / Chapter 4.2.1 --- Digitizing of Data --- p.87 / Chapter 4.2.1.1 --- Landslip Capture in Stereocord --- p.87 / Chapter 4.2.1.2 --- Data Conversion --- p.94 / Chapter 4.2.1.2.1 --- Topographic Maps - Scanning and Vectorization --- p.94 / Chapter 4.3 --- Data Editing --- p.94 / Chapter 4.3.1 --- Line Cleaning for Landslide Coverage --- p.96 / Chapter 4.3.2 --- Line Cleaning and Height Tagging for Topographic Map --- p.96 / Chapter 4.3.3 --- Editing on Terrain Classification Map --- p.97 / Chapter 4.4 --- Database Construction --- p.97 / Chapter 4.4.1 --- Data Base Design --- p.97 / Chapter 4.4.1.1 --- Graphical Data Base --- p.98 / Chapter 4.4.1.2 --- Attribute Data Base --- p.99 / Chapter 4.4.2 --- Creation of a Triangulated Irregular Network (TIN) --- p.104 / Chapter 4.5 --- Data Preparation and Pre-analysis Manipulation --- p.105 / Chapter 4.5.1 --- Extraction of Terrain Variables from TIN --- p.105 / Chapter 4.5.1.1 --- TIN'S Derived Variable - Elevation --- p.105 / Chapter 4.5.1.2 --- TIN'S Derived Variable - Gradient --- p.107 / Chapter 4.5.1.3 --- TIN'S Derived Variable - Orientation --- p.109 / Chapter 4.5.1.4 --- TIN's Derived Variable - Dimensions (surface distance) of Landslides --- p.109 / Chapter 4.5.1.5 --- Micro-DEM and Profile --- p.109 / Chapter 4.5.1.6 --- Weighting Method Adopted in Calculating the Gradient and Orientation of Primary Depletion Scar --- p.110 / Chapter 4.5.2 --- Data Preprocessing --- p.110 / Chapter 4.6 --- Summary --- p.114 / Chapter CHAPTER V: --- STATISTICAL ANALYSIS OF LANDSLIDE DISTRIBUTION --- p.115 / Chapter 5.1 --- Sampling --- p.116 / Chapter 5.1.1 --- Sampling Frame --- p.116 / Chapter 5.1.1.1 --- Simple Random Point Sampling --- p.117 / Chapter 5.1.1.2 --- Stratified Random Point Sampling --- p.117 / Chapter 5.2 --- Comparison of the Two Study Areas --- p.119 / Chapter 5.3 --- Statistical Analyses of Landslip Variables --- p.123 / Chapter 5.3.1 --- Gradient (TIN) and Elevation --- p.124 / Chapter 5.3.2 --- "Aspect, Geological Materials, Gradient, Terrain Component, Erosion & Instability, and Vegetation" --- p.126 / Chapter 5.3.2.1 --- Aspect --- p.127 / Chapter 5.3.2.2 --- Geological Materials --- p.130 / Chapter 5.3.2.3 --- Gradient --- p.132 / Chapter 5.3.2.4 --- Terrain Component --- p.137 / Chapter 5.3.2.5 --- Erosion and Instability --- p.140 / Chapter 5.3.2.6 --- WWF Vegetation --- p.140 / Chapter 5.3.3 --- Result of the Partial Model --- p.145 / Chapter 5.4 --- Logistic Regression Model --- p.147 / Chapter 5.4.1 --- Landslide Probability Mapping --- p.154 / Chapter 5.4.2 --- Testing the Model Output --- p.157 / Chapter 5.5 --- Summary --- p.161 / Chapter CHAPTER VI: --- CONCLUSIONS --- p.162 / Chapter 6.1 --- Summary of Findings --- p.162 / Chapter 6.2 --- Limitations of the Study --- p.163 / Chapter 6.3 --- Recommendations for Further Studies --- p.166 / BIBLOGRAPHY --- p.167 / APPENDICES / "APPENDIX I Draft 3.3 slope failure/deposit field survey sheet (King, 1994a)" / "APPENDIX II Landslide/deposit field description sheet (King, 1994b)" / "APPENDIX III Hourly rainfall (mm) record at N05 in September 26-27，1993 (Source: Special Projects Division, Geotechnical Engineering Office, Civil Engineering Department)" / "APPENDIX IV Hourly rainfall (mm) record at R23 in September 1993 (Source: Hydrometeorology Section, Royal Observatory, Hong Kong,1993)" / "APPENDIX V Hourly rainfall (mm) record at R31 in September 1993 (Source: Hydrometeorology Section, Royal Observatory, Hong Kong,1993)"

Thesis (MPhilAgric)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: Not only have non-trade barriers been applied in Europe and the US to agricultural products from developing countries, but protective policy is also likely to continue. Owing to the omission of fish from the discussions in the final round of agreement at Uruguay, where tariffs were significantly reduced for other agricultural products, the fish industry has not had any non tarriff barier relief in recent years. The failure of the November 1999 World Trade Organisation Meeting at Seattle to reach any agreement, has again shattered hopes of international relief for fishery products. The main assumption underlying the study was that the production of fish in Tanzania could improve significantly if the HACCP (Hazard Analysis Critical Control Points) principles were applied rigorously. It was believed that neither the prerequisite programmes, nor HACCP principles were probably applied as stringently as international standards require. The aim of the study was to review the literature on HACCP, programmes that are prerequisite for HACCP and factors that_ determine competitiveness in business and to examine the Tanzanian Nile perch industry against this background. The overall goal was to determine how the industry could become more internationally competitive. This was achieved by comparing the socio-economic reality of Tanzania with factors that are considered in the literature to affect competitiveness in general and in the fish industry specifically. To achieve the first of these aims, Tanzania's socioeconomic position as a developing country was examined. To achieve the latter, the commitment of fish processing factories to the application of HACCP principles and their compliance with prerequisite programmes were evaluated in a field study. The literature study confirms that HACCP has received international recognition in the fish industry as a factor to prevent hazards and gain competitiveness in the global fish market. However, conditions in Tanzania were shown to be insufficient to support the fisheries sector in attempting to gain such a competitive advantage. Although, Tanzania has the comparative advantage of a fishery resource base, a favourable trade policy and foreign technology and management, the macro-factors that include the infrastructure, human resource capital, foreign policy environment and the supporting industries are not supportive. For the time being, therefore, improvement can only come from the government and from the industry itself. There are several factors to which the government needs to pay attention in order to support this industry - and others - in achieving international success. These include the provision of infrastructure and facilities, the improvement of the transportation network, technological capabilities, human resource capital and the provision of safe water and electric power. However, the fish industry cannot rely on the government alone. The improvement of their product is also dependent on their own efforts. According to the findings of this study, the industry needs to comply with the basic sanitation factors and provide the necessary training to the employees and fish suppliers. Having examined the situation more closely, the assumption is proved to be correct. The fish industry in Tanzania does indeed appear to have the potential to become internationally competitive. Such success, however, will be heavily dependent on cooperation between the government and the industry / AFRIKAANSE OPSOMMING: Handelsbeperkinge op landbouproduckte vanaf ontwinkkelende in Europa en die Verenigde State toegepas. Daarbenewens sal beskermende beleidsriglyne waarskynlik in stand gehou word. Bespreking van sake met betrekking to vissery is nie by die finale rondte van ooreenstemming te Uruquay, waar tariewe vir ander landbouproduckte betekenisvol verlaag is, ingesluit nie, en daardeur is daar gedurende die laaste aantal jare geen belastingverligting vir die visindustrie gebied nie. By die World Trase Organisation se vergadering om internasionale verligting vir visproducte te verkry, weereens beskaam. Die hoofveronderstelling wat hierdie studie ondersteun, is dat visproduksie III Tanzanie betekenisvol verbeter kan word indien die can HACCP (Hazard Analysis Critical Control Points) streng toegepas word. Dit is veronderstel dat nóg die voorvereiste programme, nóg die HACCP-beginsels wat ten opsigte van internasionale standaarde vereis word, streng volgens voorskriftoegepas word. Die doel van die studie was om 'n oorsig van die literatuur oor HACCP, programme wat as HACCP-voorvereistes geld en faktore wat mededingendheid in die besigheidswereld bepaal, te verkry en om die Tanzaniese Nyl-baarsbedryf teen hierdie agterground te ondersoek. Die oorkoepelende doel was om vas te stel hoe die bedryf internasionaal meer mededingend kan word. Dit is gedoen deur middel van vergelyking tussen die sosio-ekonomiese werklikheid van Tanzanië en die faktore wat mededingendheid in die algemeen, volgens die literatuur, en die visbedryf in besonder, affekteer. Om die eeste van hiedie doelstellings te bereik, is die sosio-ekonomies posisie van Tanzanie as 'n ontwikkelende land ondersoek Om die tweede te bereik, is 'n veldstudie uitgevoer om die mate waartoe fabrieke wat vis verwerk daarop ingestel is om HACCP-beginsels toe te pas en hul gewilligheid om die programme wat as voorvereistes dien, na te kom, te evalueer. Die literatuurstudie het bevestig dat HACCP internasionale erkenning geniet as 'n faktor om risikO in de visbedryf uit te skakel en mededingendheid op die wereldmark vir vis te verwerf. Daar is egter bewys dat toetstande in Tanzanie ontoereikend is om die visserysektor in die verwewing van'n mededingende voorsprong te ondersteun. Alhoewel Tanzanië oor die relatiewe voordele van vissery as 'n hulpbron, gunstige handelsbeleid en buitelandse tegnologie en bestuur bestik, bied die makrofaktore soos infrastruktuur, kapitaal III die vorm van menslike hulpbronne, die buitelandse beleidsomgewing en die ondersteunende bedrywe nie genoeg ondersteuning nie. Vir die hede, kan ontwikkeling dus slegs deur die regering en die bedryf self bewekstelling word. Daar is verskeie faktore waaraan die regering aandag moet skenk om hierdie bedryf-en ander bedrywe-in die verkryging van internasionale sukses te ondersteun. Sulke faktore omvat die daarstelling van infrastruktuur en fasiliteite, die verbetering van die vervoernetwerk, tegnologiese vermoens en menslike hulpbronkapitaal, en voorsiening van onbesmette water en elektriese krag. Die visbedryf kan egter nie net op die regering steun nie. Die verbetering van die product is van die bedryf self afhanklik. Die bevindings van hierdie studie dui daarop dat die bedryf die basiese faktore betreffende sanitêre beginsels moet onderhoue en die vereiste opleiding aan diensnemers moet verskaf. By die nadere ondersoek van die situasie is die oorspronklike veronderstelling korrek bewys. Die visbedryf in Tanzanië beskik oor die potensiaal om internasionaal medengend te word. Sodanige sukses sal egter uiters afhanklik wees van samewerking tussen die regering en die bedryf.

In South Africa there is a need within the milling industry for controlling food safety especially due to customer's demands and government's regulations. The best way to ensure food safety is with the implementation of a HACCP based food safety system. Therefore, the principal aim of this study was to develop a generic HACCP model for the flour milling industry. Afterwards this generic model can then be adapted for each specific mill and its needs.

Doctor of Philosophy / Department of Computing and Information Sciences / John M. Hatcliff / Medical devices have traditionally been designed, built, and certified for use as monolithic units. A new vision of "Medical Application Platforms" (MAPs) is emerging that would enable compositional medical systems to be instantiated at the point of care from a collection of trusted components. This work details efforts to create a development environment for applications that run on these MAPs. The first contribution of this effort is a language and code generator that can be used to model and implement MAP applications. The language is a subset of the Architecture, Analysis and Design Language (AADL) that has been tailored to the platform-based environment of MAPs. Accompanying the language is software tooling that provides automated code generation targeting an existing MAP implementation. The second contribution is a new hazard analysis process called the Systematic Analysis of Faults and Errors (SAFE). SAFE is a modified version of the previously-existing System Theoretic Process Analysis (STPA), that has been made more rigorous, partially compositional, and easier. SAFE is not a replacement for STPA, however, rather it more effectively analyzes the hardware- and software-based elements of a full safety-critical system. SAFE has both manual and tool-assisted formats; the latter consists of AADL annotations that are designed to be used with the language subset from the first contribution. An automated report generator has also been implemented to accelerate the hazard analysis process. Third, this work examines how, independent of its place in the system hierarchy or the precise configuration of its environment, a component may contribute to the safety (or lack thereof) of an entire system. Based on this, we propose a reference model which generalizes notions of harm and the role of components in their environment so that they can be applied to components either in isolation or as part of a complete system. Connections between these formalisms and existing approaches for system composition and fault propagation are also established. This dissertation presents these contributions along with a review of relevant literature, evaluation of the SAFE process, and concludes with discussion of potential future work.

A systematic framework has been developed to assess what it is that is at risk in any given telephone exchange. This critical area procedure is designed to identify high risk areas, both in terms of potential property damage and business interruption. This procedure utilizes a functionally based approach that is pictorial in presentation n and well suited to management decision making processes.

Landslides represent a serious hazard to people and property in the Pacific Northwest. Currently, the factors leading to sudden catastrophic failure vs. gradual slow creeping are not well understood. Utilizing high-resolution monitoring techniques at a sub-annual temporal scale can help researchers better understand the mechanics of mass wasting processes and possibly lead to better mitigation of their danger. This research used historical imagery analysis, precipitation data, aerial lidar analysis, Structure from Motion (SfM) photogrammetry, terrestrial laser scanning (TLS), and hydrologic measurements to monitor displacement of the Silt Creek Landslide in the western Cascade Mountain Range in Linn County, Oregon. This landslide complex is ~4 km long by ~400 m wide. The lower portion of the landslide reactivated following failure of an internal scarp in June 2014. Precipitation was measured on site and historical precipitation data was determined from a nearby SNOTEL site. Analysis of aerial lidar data found that the internal scarp failure deposited around 1.00x106 m3 of material over an area of 1.20x105 m2 at the uppermost portion of the reactivated slide. Aerial lidar analysis also found that displacement rates on the slide surface were as high as 3 m/yr during the 2015 water year, which was the year immediately following the failure. At the beginning of the 2016 water year, very low altitude aerial images were collected and used to produce point cloud data, via SfM, of a deformed gravel road which spans a portion of the reactivated slide. The SfM data were complimentary to the aerial and TLS scans. The SfM point cloud had an average point density of >7500 points per square meter. The resulting cloud was manipulated in 3D software to produce a model of the road prior to deformation. This was then compared to the original deformed model. Average displacement found in the deformed gravel road was 7.5 m over the 17 months between the scarp failure and the collection of the images, or ~3 m/yr. TLS point clouds were collected quarterly over the course of the 2016 water year at six locations along the eastern margin of the reactivated portion of the landslide. These 3D point cloud models of the landslide surface had an average density of 175 points per square meter. Scans were georeferenced to UTM coordinates and relative alignment of the scans was accomplished by first using the iterative closest point algorithm to align stable, off-slide terrain, and then applying the same rigid body translation to the entire scan. This was repeated for each scan at each location. Landmarks, such as tree trunks, were then manually selected at each location and their coordinates were recorded from the initial scan and each successive scan to measure displacement vectors. Average annual displacement for the 2016 water year ranged from a maximum of 0.92 m/yr in the uppermost studied area of the slide, to a low of 0.1 m/yr at the toe. Average standard deviation of the vectors of features on stable areas was 0.039 m, corresponding to a minimum detectable displacement of about ±4 cm. Displacement totals decreased with increasing distance downslope from the internal scarp failure. Additionally, displacement tended to increase with increasing distance laterally onto the slide body away from the right margin at all locations except the uppermost, where displacement rates were relatively uniform for all landmarks. Volumetric discharge measurements were collected for Silt Creek in 2016 using salt dilution gauging and found that discharge in the upslope portion of the study area was ~1 m3/s and increased to ~1.6 m3/s in the downslope portion. Landslide displacement rates were found to be much lower during the 2016 water year than during the 2015 water year, despite higher precipitation. This suggests that the over-all displacement trend was decoupled from precipitation values. Displacement rates at all locations on the slide decreased with each successive scan period with some portions of the landslide stopping by autumn of 2016, suggesting the study captured the slide as it returned to a state of stability. The spatial and temporal pattern of displacement is consistent with the interpretation that the landslide reactivation was a response to the undrained load applied by the internal scarp failure. This finding highlights the importance of detailed landslide monitoring to improve hazard estimation and quantification of landslide mechanics. This study provides new evidence that supports previous research showing that internal processes within landslide complexes can have feedback relationships, combines several existing 3D measurement tools to develop a detailed landslide monitoring methodology, uses a novel approach to landslide surface deformation measurements using SfM, and suggests that landslide initiation models which rely heavily on precipitation values may not account for other sources of landslide activation.