Screen Capture for Sensitive Systems

Maintaining usable security in application domains such as healthcare or power systems requires an ongoing conversation among stakeholders such as end-users, administrators, developers, and policy makers. Each party has power to influence the design and implementation of the application and its security posture, and effective communication among stakeholders is one key to achieving influence and adapting an application to meet evolving needs. In this thesis, we develop a system that combines keyboard/video/mouse (KVM) capture with automatic text redaction to produce precise technical content that can enrich stakeholder communications, improve end-user influence on system evolution, and help reveal the definition of ``usable security.\u27\u27 Text-redacted screen captures reduce sensitivity of captured material and thus can facilitate timely data sharing among stakeholders. KVM-based capture makes our system both application and operating-system independent because it eliminates software-interface dependencies on capture targets. Thus, our work can be used to instrument closed or certified systems where capture software cannot be installed or documentation and support lack. It can instrument widely-varying platforms that lack standards-compliance and interoperability or redact special document formats while displayed onscreen. We present three techniques for redacting text from screenshots and two redaction applications. One application can capture, text redact, and edit screen video and the other can text redact and edit static screenshots. We also present empirical measurements of redaction effectiveness and processing latency to demonstrate system performance. When applied to our principal dataset, redaction removes text with over 93\% accuracy and simultaneously preserves more than 76\% of image pixels on average. Thus by default, it retains more visual context than a technique such as blindly redacting entire screenshots. Finally, our system redacts each screenshot in 0.1 to 21 seconds depending on which technique it applies

Energy based dissolution simulation using smoothed particle hydrodynamic sampling

Fluid simulation plays an important role in Computer Graphics and has wide applications in film and games. The desire for an improved physically-based fluid simulation solver has grown hand in hand with the advances made in Computer Graphics. Interesting fluid behaviours emerge when solid objects are added to a simulation: when fluid and solid make contact, they do not only have a physical interaction (e.g., buoyancy), but also a chemical reaction (e.g., dissolution) under the right conditions. Dissolution is one of the most common natural phenomena which is an important visual effect in fluid simulation. However this phe- nomenon is difficult to simulate due to the complexity of the behaviour and there are only few techniques available. A novel unified particle-based method for approximating chemical dis- solution is introduced in this thesis which is fast, predictable and visually plausible. The dissolution algorithm is derived using chemical Collision Theory and integrated into a Smoothed Particle Hydrodynamics (SPH) framework. The Collision Theory of chemistry is used as an analogy to the dissolution process modelling. Dissolution occurs when solute submerges into solvent. Physical laws govern the local excitation of so- lute particles based on the relative motion with solvent particles. When the local excitation energy exceeds a user specified threshold (activation energy), the particle will be dislodged from the solid. Unlike previous methods, this dissolution model ensures that the dissolution result is in- dependent of solute sampling resolution. A mathematical relationship is also established between the activation energy, the interfacial surface area, and the total dissolution time — allowing for intuitive artistic con- trol over the global dissolution rate. Applications of this method are demonstrated using a number of practical examples, including antacid pills dissolving in water and hydraulic erosion of non-homogeneous ter- rains. Both solutes and solvents are represented by particles, and the dis- tribution of the solute particles greatly affects the plausibility of the dissolution simulation. An even but stochastic distribution of particles on both the surface and within the volume of the solute is essential for a good visual simulation of the dynamic process of dissolution. A new iterative particle-based sampling method derived from SPH is introduced in this thesis which can generate a range of blue noise pat- terns and is computationally efficient, controllable and has a variety of applications. This approach resolves many of the limitations of classic blue noise methods, such as the lack of controllability or varying the dis- tribution properties of the generated samples. Fast sampling is achieved in general dimensions for curves, surfaces and volumes. By varying a sin- gle parameter, the proposed method can generate a range of controllable blue noise samples with different distribution properties which are suit- able for various applications such as adaptive sampling and multi-class sampling. The SPH sampling approach is used for solute particle distribution which guarantees a predictable and smooth dissolution process thanks to the evenly distributed density and also gives the user control of the volume change during the phase transition. The proposed SPH sampling method achieves better visual effects compared with simple grid sampling and other blue noise sampling methods. Our energy based dissolution simulation with SPH sampled solute and solvent ensures that the dissolution behaviour is physically and chemi- cally plausible, while supporting features such as object separation and sharp feature rounding. The simulation is parallelized per particle on a GPU to enhance the performance

Disordered Proteins: Connecting Sequences to Emergent Properties

Many IDPs participate in coupled folding and binding reactions and form alpha helical structures in their bound complexes. Alanine, glycine, or proline scanning mutagenesis approaches are often used to dissect the contributions of intrinsic helicities to coupled folding and binding. These experiments can yield confounding results because the mutagenesis strategy changes the amino acid compositions of IDPs. Therefore, an important next step in mutagenesis-based approaches to mechanistic studies of coupled folding and binding is the design of sequences that satisfy three major constraints. These are (i) achieving a target intrinsic alpha helicity profile; (ii) fixing the positions of residues corresponding to the binding interface; and (iii) maintaining the native amino acid composition. Here, we report the development of a Genetic Algorithm for Design of Intrinsic secondary Structure (GADIS) for designing sequences that satisfy the specified constraints. We describe the algorithm and present results to demonstrate the applicability of GADIS by designing sequence variants of the intrinsically disordered PUMA system that undergoes coupled folding and binding to Mcl-1. Our sequence designs span a range of intrinsic helicity profiles. The predicted variations in sequence-encoded mean helicities are tested against experimental measurements.There is a significant collection of proteins with repeating blocks of oppositely charged residues where the consensus sequence is a block of four Glu residues followed by a block of four Lys or Arg residues, (Glu4(Lys/Arg)4)n. These proteins have been experimentally shown to form long single alpha helices (SAHs) under biologically relevant conditions. However, these results are confounding to disorder predictors and to certain atomistic simulations in that both predict these sequences to be strongly disordered. The current working hypothesis is that SAHs are stabilized by i:i+4 salt bridges between opposite charges in consecutive helical turns. We test the merits of this hypothesis to understand the sequence-encoded preference for SAHs and the logic behind the failure of certain atomistic simulations in anticipating the preference for stable SAHs.In simulations with fixed charges the favorable free energy of solvation of charged residues and the associated loss of sidechain entropy hinders the formation of SAHs. We proposed that alterations to charge states induced by sequence context might play an important role in stabilizing SAHs. We tested this hypothesis using a (Glu4Lys4)n repeat protein and a simulation strategy that permits the substitution of charged residues with neutralized protonated or deprotonated variants of Glu / Lys. Our results predict that stable SAH structures derive from the neutralization of approximately half the Glu residues. These findings explain experimental observations and also provide a coherent rationale for the failure of simulations based on fixed charge models. Large-scale sequence analysis reveals that naturally occurring sequences often include defects in charge patterns such as Gln or Ala substitutions. This sequence-encoded incorporation of uncharged residues combined with neutralization of charged residues might tilt the balance toward alpha helical conformations.Micron-sized, non-membrane bound cellular bodies can form as the result of collective interactions between modules of distinct multidomain proteins. Li et al. have examined the phase diagrams that result for polymers of SH3 domains and proline-rich modules (PRMs) while varying the number of interacting domains. It is noteworthy that flexible, intrinsically disordered linkers connect the interacting units within each polymer. Conventional wisdom holds that linkers play a passive role in determining the phase behavior of multidomain proteins that undergo phase separations. Here, we ask if this view is accurate. The motivation for our work comes from recent studies that have uncovered a rich diversity of composition-to-conformation and sequence-to-conformation relationships for intrinsically disordered proteins. The central finding is that disordered regions of proteins have distinct sequence-encoded conformational preferences. Accordingly, we reasoned that the conformational properties of linkers might be a contributing factor, in addition to polyvalency, to the phase behavior of multidomain proteins.We have developed and deployed a three-dimensional lattice model to arrive at a predictive framework to query the effects of linkers on the phase diagrams of polyvalent systems. We find that the critical concentration for phase transition can be influenced by the conformational properties of linkers. Specifically, our results show that linkers modulate the cooperative binding between domains of polymers that are already bound together. Depending on their conformational properties, linkers can also block access to the binding domains via excluded volume effects. Additionally, we find that the properties of the linkers can lead to controls over the mixing of proteins in these bodies. Specifically, we find that there are large ranges of parameters for three protein systems where the bodies isolate specific proteins to different regions of the bodies instead of uniformly mixing them. This result is validated by recent findings of organization inside some observed bodies

Computational approaches to semantic change (Volume 6)

Semantic change — how the meanings of words change over time — has preoccupied scholars since well before modern linguistics emerged in the late 19th and early 20th century, ushering in a new methodological turn in the study of language change. Compared to changes in sound and grammar, semantic change is the least understood. Ever since, the study of semantic change has progressed steadily, accumulating a vast store of knowledge for over a century, encompassing many languages and language families. Historical linguists also early on realized the potential of computers as research tools, with papers at the very first international conferences in computational linguistics in the 1960s. Such computational studies still tended to be small-scale, method-oriented, and qualitative. However, recent years have witnessed a sea-change in this regard. Big-data empirical quantitative investigations are now coming to the forefront, enabled by enormous advances in storage capability and processing power. Diachronic corpora have grown beyond imagination, defying exploration by traditional manual qualitative methods, and language technology has become increasingly data-driven and semantics-oriented. These developments present a golden opportunity for the empirical study of semantic change over both long and short time spans

Microgravity Science and Applications: Program Tasks and Bibliography for Fiscal Year 1996

NASA's Microgravity Science and Applications Division (MSAD) sponsors a program that expands the use of space as a laboratory for the study of important physical, chemical, and biochemical processes. The primary objective of the program is to broaden the value and capabilities of human presence in space by exploiting the unique characteristics of the space environment for research. However, since flight opportunities are rare and flight research development is expensive, a vigorous ground-based research program, from which only the best experiments evolve, is critical to the continuing strength of the program. The microgravity environment affords unique characteristics that allow the investigation of phenomena and processes that are difficult or impossible to study an Earth. The ability to control gravitational effects such as buoyancy driven convection, sedimentation, and hydrostatic pressures make it possible to isolate phenomena and make measurements that have significantly greater accuracy than can be achieved in normal gravity. Space flight gives scientists the opportunity to study the fundamental states of physical matter-solids, liquids and gasses-and the forces that affect those states. Because the orbital environment allows the treatment of gravity as a variable, research in microgravity leads to a greater fundamental understanding of the influence of gravity on the world around us. With appropriate emphasis, the results of space experiments lead to both knowledge and technological advances that have direct applications on Earth. Microgravity research also provides the practical knowledge essential to the development of future space systems. The Office of Life and Microgravity Sciences and Applications (OLMSA) is responsible for planning and executing research stimulated by the Agency's broad scientific goals. OLMSA's Microgravity Science and Applications Division (MSAD) is responsible for guiding and focusing a comprehensive program, and currently manages its research and development tasks through five major scientific areas: biotechnology, combustion science, fluid physics, fundamental physics, and materials science. FY 1996 was an important year for MSAD. NASA continued to build a solid research community for the coming space station era. During FY 1996, the NASA Microgravity Research Program continued investigations selected from the 1994 combustion science, fluid physics, and materials science NRAS. MSAD also released a NASA Research Announcement in microgravity biotechnology, with more than 130 proposals received in response. Selection of research for funding is expected in early 1997. The principal investigators chosen from these NRAs will form the core of the MSAD research program at the beginning of the space station era. The third United States Microgravity Payload (USMP-3) and the Life and Microgravity Spacelab (LMS) missions yielded a wealth of microgravity data in FY 1996. The USMP-3 mission included a fluids facility and three solidification furnaces, each designed to examine a different type of crystal growth

The influence of herbaceous vegetaiton and its structural characteristics on sediment retention on floodplains

Sediment and nutrient retention are important ecosystem functions floodplain meadows fulfil. While it is known that the inundated floodplain vegetation purifies the water during floods, little is known about the processes behind. I investigated the effect of the vegetation structure on sedimentation at three hierarchical scales, leaf, patch, and floodplain scale and used two approaches, experiments and an in situ field study. In the leaf experiment (study 1) I inundated single leaves into sediment rich water. The results showed that leaf pubescence increased sedimentation on leaf surfaces and that for leaves without hairs, the sedimentation increased with decreasing leaf area. In the flume experiment (study 2) I investigated the effects of community characteristics of vegetation patches regarding their capacity to capture sediment. I manipulated the leaf pubescence, the community density, the community height and the structural diversity (high-high vs high-low growing species) of the patches. The results show that all four investigated community characteristics increased the sediment retention. In the second flume experiment (study 3), I investigated the effect of species richness of vegetation patches on sediment retention. The results showed the importance of the vegetation biomass and identity effects of single species, but no clear effect of species richness. For the in situ field measurements (study 4), I measured sedimentation during a real flood event along the Mulde River in Germany. With sediment traps and biomass harvests I quantified the sedimentation underneath as well as on the vegetation. The results showed that besides the vegetation biomass, the topographical parameter ‘hydrological distance’ (pathway of lowest elevation the water travels to the site) is important for sediment and especially nutrient retention. Even though sediment retention is highest close by the river, sedimentation is still reasonably high far insight the floodplain and especially nutrient retention (C, N and P) increase with hydrological distance. From the sum of results I can derive four management strategies for floodplains to increase the sediment retention. First, reduced mowing for more standing biomass during flood season, wherefore trade-offs with other ecosystem functions need to be evaluated carefully. Second, promotion of structural diversity, possible via species diversity. Third, promotion of species with characteristics that increase sediment, such as pubescent leaves. Forth, preserving or recreating topographic complexity in the floodplain. Overall, I showed that the specific structures of herbaceous vegetation are highly beneficial for sediment and nutrient retention on floodplains.:Table of contents 1. General introduction 6 1.1 The Mulde River and the “Wilde Mulde” project 7 1.2 Sediment retention on floodplains 8 1.3 Vegetation causes fine sedimentation 11 1.4 Structural characteristics 12 1.4.1 Structural identity of species 13 1.4.2 Structural identity of communities 14 1.4.3 Structural diversity of communities 15 1.5 Links between studies 17 2. Methodological features 19 2.1 Study area “Wilde Mulde” 19 2.2 Leaf roughness measurement 22 2.3 Experimental set up of the flume experiment 24 3. Original contributions 26 3.1 Paper 1 - Leaf area and pubescence drive sedimentation on leaves surfaces during flooding 26 3.2 Paper 2 – Plant structural diversity alters sediment retention on and underneath herbaceous vegetation in a flume experiment 44 3.3 Paper 3 – Effects of plant species identity overrides diversity effects in explaining sedimentation within vegetation in a flume experiment 65 3.4 Paper 4 – Vegetation characteristics control sediment and nutrient retention on but not underneath vegetation in floodplain meadows 77 4. Discussion 107 4.1 Mechanistic parallels among scales 109 4.2 Effects of species diversity in relation to species identity 112 4.3 Transferability and its limitations 113 4.4 The ecosystem function of sediment retention 114 4.4.1 Floodplain management for sediment retention 115 4.4.2 Sediment retention in the context of other ecosystem functions 117 4.4.3 Floodplain management for sediment retention along the Lower Mulde River 119 5. Outlook 122 5.1 Leaf roughness 122 5.2 Diversity experiment 123 5.3 Approaches for new management strategies 124 5.4 Extrapolation with remote sensing 125 5.5 Sediment budget 126 6. Conclusion 128 7. References 130 8. Summary 143 9. Zusammenfassung 149 Acknowledgements 155 Author contribution statement 156 Curriculum vitae 164 List of publications 166 Selbstständigkeitserklärung 16

New Technologies in the Oil and Gas Industry

Oil and gas are the most important non-renewable sources of energy. Exploring, producing and managing these resources in compliance with HSE standards are challenging tasks. New technologies, workflows and procedures have to be implemented.This book deals with some of these themes and describes some of the advanced technologies related to the oil and gas industry from HSE to field management issues. Some new technologies for geo-modeling, transient well testing and digital rock physics are also introduced. There are many more technical topics to be addressed in future books. This book is aimed at researchers, petroleum engineers, geoscientists and people working within the petroleum industry