Forensic Data Properties of Digital Signature BDOC and ASiC-E Files on Classic Disk Drives

Käesolevas magistritöös vaadeldakse BDOC ja ASiC-E digitaalselt allkirjastatud dokumendikonteinerite sisu ning kirjeldatakse nende huvipakkuvaid omadusi. Teatava hulga näidiskonteinerite vaatlemise järel pakub autor välja faili päise ja faili jaluse kombinatsiooni (signatuuri), mis oluliselt parandab nimetatud failide kustutatud olekust sihitud taastamist külgnevatest klastritest NTFS vormindatud tihendamata kettal, võttes arvesse klassikalise kõvaketta geomeetriat. Ühtlasi kirjeldab autor kohtuekspertiisi koha pealt tähendust omavaid andmeid ZIP kohaliku faili päises ja keskkataloogi kirjes, XML signatuuris ja ASN.1 kodeeritud kihtides ning nende kättesaamise algoritmi. Nendele järeldustele tuginedes loob autor Phytoni skripte ja viib läbi mitmeid teste failide taastamiseks faili signatuuri järgi ning huvipakkuvate andmete väljavõtmiseks. Teste viiakse läbi teatava valiku failide üle ja tulemusi võrreldakse mitme kohtuekspertiisis laialt kasutatava peavoolu töökeskkonnaga, samuti mõningate andmetaaste tööriistadega. Lõpuks testitakse magistritöö käigus pakutud digitaalselt allkirjastatud dokumentide taastamiseks mõeldud signatuuri ja andmete väljavõtmise algoritmi suurel hulgal avalikust dokumendiregistrist pärit kehtivate dokumentidega, mis saadi kätte spetsiaalselt selleks kirjutatud veebirobotiga. Nimetatud teste viiakse läbi dokumentide üle, mille hulgas on nii digitaalselt allkirjastatud dokumente kui ka teisi, nendega struktuurilt sarnaseid dokumente.This thesis reviews the contents and observes certain properties of digitally signed documents of BDOC and ASiC-E container formats. After reviewing a set of sample containers, the author comes up with a header and footer combination (signature) significantly improving pinpointed carving-based recovery of those files from a deleted state on NTFS formatted uncompressed volumes in contiguous clusters, taking into account the geometry of classic disk drives. The author also describes forensically meaningful attributive data found in ZIP Headers and Central Directory, XML signatures as well as embedded ASN.1 encoded data of the sample files and suggests an algorithm for the extraction of such data. Based on these findings, the author creates scripts in Python and executes a series of tests for file carving and extraction of attributive data. These tests are run over the samples placed into unallocated clusters and the results are compared to several mainstream commercial forensic examination suites as well as some popular data recovery tools. Finally, the author web-scrapes a large number of real-life documents from a government agency’s public document registry. The carving signature and the data-extractive algorithm are thereafter applied on a larger scale and in an environment competitively supplemented with structurally similar containers

Open source software in quantum computing

Open source software is becoming crucial in the design and testing of quantum algorithms. Many of the tools are backed by major commercial vendors with the goal to make it easier to develop quantum software: this mirrors how well-funded open machine learning frameworks enabled the development of complex models and their execution on equally complex hardware. We review a wide range of open source software for quantum computing, covering all stages of the quantum toolchain from quantum hardware interfaces through quantum compilers to implementations of quantum algorithms, as well as all quantum computing paradigms, including quantum annealing, and discrete and continuous-variable gate-model quantum computing. The evaluation of each project covers characteristics such as documentation, licence, the choice of programming language, compliance with norms of software engineering, and the culture of the project. We find that while the diversity of projects is mesmerizing, only a few attract external developers and even many commercially backed frameworks have shortcomings in software engineering. Based on these observations, we highlight the best practices that could foster a more active community around quantum computing software that welcomes newcomers to the field, but also ensures high-quality, well-documented code.Comment: 22 pages, 4 figure

Influence of Material Parameter Variability on the Predicted Coronary Artery Biomechanical Environment via Uncertainty Quantification

Central to the clinical adoption of patient-specific modeling strategies is demonstrating that simulation results are reliable and safe. Simulation frameworks must be robust to uncertainty in model input(s), and levels of confidence should accompany results. In this study we applied a coupled uncertainty quantification-finite element (FE) framework to understand the impact of uncertainty in vascular material properties on variability in predicted stresses. Univariate probability distributions were fit to material parameters derived from layer-specific mechanical behavior testing of human coronary tissue. Parameters were assumed to be probabilistically independent, allowing for efficient parameter ensemble sampling. In an idealized coronary artery geometry, a forward FE model for each parameter ensemble was created to predict tissue stresses under physiologic loading. An emulator was constructed within the UncertainSCI software using polynomial chaos techniques, and statistics and sensitivities were directly computed. Results demonstrated that material parameter uncertainty propagates to variability in predicted stresses across the vessel wall, with the largest dispersions in stress within the adventitial layer. Variability in stress was most sensitive to uncertainties in the anisotropic component of the strain energy function. Unary and binary interactions within the adventitial layer were the main contributors to stress variance, and the leading factor in stress variability was uncertainty in the stress-like material parameter summarizing contribution of the embedded fibers to the overall artery stiffness. Results from a patient-specific coronary model confirmed many of these findings. Collectively, this highlights the impact of material property variation on predicted artery stresses and presents a pipeline to explore and characterize uncertainty in computational biomechanics.Comment: To appear: Biomechanics and Modeling in Mechanobiolog

Suspended Sediment Transport and Fluid Mud Dynamics in Tidal Estuaries

Cohesive sediments transport has been systematically studied for more than a century from field studies, laboratory experiments, and mathematical models. During the past decades, the accumulation of flocculated cohesive sediments and the formation of weakly consolidated mud deposits, including fluid mud, gained increased attention. Despite extensive research efforts, the governing processes of fluid mud formation are far from being fully understood. The primary objective of this study is to investigate tide-driven dynamics of fluid mud in estuaries. State of the art hydroacoustic subbottom (SES) and current velocity profilers (ADCP) are used, to measure fluid mud dynamics on appropriate temporal and spatial scales. Connected fields of research are to be taken into account, such as bedload transport and the influence of subaqueous dunes on the turbulent flow field. Technical aspects are considered, in particular the detection of suspended cohesive sediments. Measurements are conducted in the Ems and the Weser estuary, located along the North Sea coast of Germany. Other study sites in the North Sea are the Jade Bay in Germany and the Grådyb tidal inlet in Denmark. Not only the combined deployment of different hydroacoustic profiling devices but also the combined processing of collected data allows fluid mud dynamics to be studied in great detail. Combined processing is implemented in a software tool, programmed in MATLABTM. The software facilitates the acoustic backscatter calibration with respect to suspended sediment concentration (SSC) and thus joins information on hydrodynamic, near-bed density stratification and SSC in the water column. A large data set is collected in the Weser estuary and analysed regarding tide-driven dynamics of fluid mud. Fluid mud does not appear in the suggested form of a contiguous layer, but is deposited in depressions, in troughs of subaqueous dunes, as well as in the form of mud drapes during slack water. Entrainment is controlled by local production of turbulence, which is, in turn, influenced by local morphology. Fluid mud deposits in dune troughs are rapidly entrained, induced by strong turbulent stresses which are generated at the dune crest and advected in direction of the lutocline, i.e. the density gradient between fluid mud and the water column. Mobile mud layers are significantly resistant to entrainment and partly survive half a tidal cycle. Continuous feeding by slack water deposition induces a positive feedback of increasing concentrations and increased damping of turbulence, which inevitably leads to the formation of erosion-resistant estuarine mud deposits. A new method for the detection of density stratification is introduced, based on the backscatter gradient of acoustic current profiles. Furthermore, the gradient Richardson stability criterion is also expressed in terms of the backscatter gradient and proved to be applicable in order to assess lutocline stability under intricate hydrodynamic conditions in the Ems estuary. In the heavily engineered Ems estuary, weir closure during flood slack water and the subsequent release of captured water masses induce the flushing of the estuary and catastrophic downstream advection of fluid mud. By the time the estuary returns to flood-dominated conditions, fluid mud is rapidly advected upstream and re-established in the upper part of the estuary. In the Grådyb tidal inlet channel bedload transport in presence of large dunes is determined on the basis of highly accurate multibeam measurements. Bathymetrical changes are converted into bedload transport rates, which are not predicted by classical bedload transport formulae due to variations in grain-size composition of the mobilised sediment. Results from this study are applied to the Weser estuary to infer that lee-side deposition occurs simultaneously to the entrainment of fluid mud in dune troughs. An instrumental study conducted in the Jade Bay concerning suspended sediment dynamics reveals that suspended sediment is transported in form of turbidity clouds. Thereby, acoustic methods underestimate SSC when large aggregates are present. Several floc populations coexist in the water column, covering a wide range of sizes from a few microns to millimetre size

SeaWiFS technical report series. Volume 5: Ocean optics protocols for SeaWiFS validation

Protocols are presented for measuring optical properties, and other environmental variables, to validate the radiometric performance of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), and to develop and validate bio-optical algorithms for use with SeaWiFS data. The protocols are intended to establish foundations for a measurement strategy to verify the challenging SeaWiFS accuracy goals of 5 percent in water-leaving radiances and 35 percent in chlorophyll alpha concentration. The protocols first specify the variables which must be measured, and briefly review rationale. Subsequent chapters cover detailed protocols for instrument performance specifications, characterizing and calibration instruments, methods of making measurements in the field, and methods of data analysis. These protocols were developed at a workshop sponsored by the SeaWiFS Project Office (SPO) and held at the Naval Postgraduate School in Monterey, California (9-12 April, 1991). This report is the proceedings of that workshop, as interpreted and expanded by the authors and reviewed by workshop participants and other members of the bio-optical research community. The protocols are a first prescription to approach unprecedented measurement accuracies implied by the SeaWiFS goals, and research and development are needed to improve the state-of-the-art in specific areas. The protocols should be periodically revised to reflect technical advances during the SeaWiFS Project cycle

An Open Source Cyberinfrastructure for Collecting, Processing, Storing and Accessing High Temporal Resolution Residential Water Use Data

Collecting and managing high temporal resolution residential water use data is challenging due to cost and technical requirements associated with the volume and velocity of data collected. We developed an open-source, modular, generalized architecture called Cyberinfrastructure for Intelligent Water Supply (CIWS) to automate the process from data collection to analysis and presentation of high temporal residential water use data. A prototype implementation was built using existing open-source technologies, including smart meters, databases, and services. Two case studies were selected to test functionalities of CIWS, including push and pull data models within single family and multi-unit residential contexts, respectively. CIWS was tested for scalability and performance within our design constraints and proved to be effective within both case studies. All CIWS elements and the case study data described are freely available for re-use

Study of neural circuits using multielectrode arrays in movement disorders

Treballs Finals de Grau d'Enginyeria Biomèdica. Facultat de Medicina i Ciències de la Salut. Universitat de Barcelona. Curs: 2022-2023. Tutor/Director: Rodríguez Allué, Manuel JoséNeurodegenerative movement-related disorders are characterized by a progressive degeneration and loss of neurons, which lead to motor control impairment. Although the precise mechanisms underlying these conditions are still unknown, an increasing number of studies point towards the analysis of neural networks and functional connectivity to unravel novel insights. The main objective of this work is to understand cellular mechanisms related to dysregulated motor control symptoms in movement disorders, such as Chorea-Acanthocytosis (ChAc), by employing multielectrode arrays to analyze the electrical activity of neuronal networks in mouse models. We found no notable differences in cell viability between neurons with and without VPS13A knockdown, that is the only gene known to be implicated in the disease, suggesting that the absence of VPS13A in neurons may be partially compensated by other proteins. The MEA setup used to capture the electrical activity from neuron primary cultures is described in detail, pointing out its specific characteristics. At last, we present the alternative backup approach implemented to overcome the challenges faced during the research process and to explore the advanced algorithms for signal processing and analysis. In this report, we present a thorough account of the conception and implementation of our research, outlining the multiple limitations that have been encountered all along the course of the project. We provide a detailed analysis on the project’s economical and technical feasibility, as well as a comprehensive overview of the ethical and legal aspects considered during the execution

Multiscale Mechanical, Structural, And Compositional Response Of Tendon To Static And Dynamic Loading During Healing

The extracellular matrix (ECM) is a major component of the biomechanical environment with which tendon cells (tenocytes) interact. Alterations to matrix structural and mechanical properties due to mechanical loading may promote normal tendon homeostasis or create pathological conditions. For example, fatigue loading of tendon elevates collagen fiber waviness (crimp), which correlates linearly with tissue laxity. The tendon ECM may also be altered following tendon injury. Aberrant tissue phenotypes caused by tendon ruptures are exemplified not only at transcript and protein levels, but also can extend to include disorganized collagen structure, inferior mechanical properties, and reduced in vivo limb function in animals. This dissertation explores the interface between dynamic loading and tendon healing across multiple length scales using living tendon explants. This work begins to define the implications of macroscale mechanical loading on collagen structure and tenocyte response in uninjured and healing tendon, and provides a foundation for the development of new strategies to improve tendon healing. Ultimately, this work helps our understanding of tendon’s multiscale response to loading, provides a framework for the micromechanical environment that tenocytes interact in response to dynamic loading and healing, and lays important groundwork for benchmarks for tendon tissue engineering. The multiscale response to mechanical loading, which is a hallmark of clinical rehabilitation protocols, is necessary to determine the ramifications of various macroscale loading protocols. Additionally, these results provide benchmarks for the environments in which tendon cells may experience following cell delivery therapies. Several exciting future avenues of research are possible that would highly impact basic science research of tendon function and lead to potentially translatable approaches that could improve tendon injury onset and healing response. In conclusion, this dissertation provides a strong foundation on which future experimental and computational studies can build to fully elucidate the multiscale mechanisms that govern strain transfer in tendon

Detecting bedform migration from high-resolution multibeam bathymetry in Portsmouth Harbor, New Hampshire, USA

A study was undertaken to quantify dune migration in Portsmouth Harbor, New Hampshire, USA from repeat high-resolution multibeam echosounder (MBES) surveys. Repeat MBES surveys were conducted in June 2007 and July 2008 over periods ranging from 6 hours to 7 days in order to capture the response of dune morphology to ebb-flood and spring-neap tidal cycles. A new technique was developed for detecting bedform migration. This approach utilizes a fingerprint-detection algorithm (Bishnu et al., 2002) to convert the bathymetric surface to a binary map of bedform crests, which are subsequently tracked using a spatial cross-correlation technique (Duffy and Hughes-Clarke, 2005). Acoustic current-meter observations from July 2008 provided context for the observed bedform-migration patterns, and were subsequently used to compute bed shear stress. Results indicate that dune migration occurred over periods as short as 6 hours. Dune migration distances in excess of 2 m were observed over 6- and 7-day periods

A real-time PCR assay for accurate quantification of the individual members of the Altered Schaedler Flora microbiota in gnotobiotic mice

Changes in the gastrointestinal microbial community are frequently associated with chronic diseases such as Inflammatory Bowel Diseases. However, understanding the relationship of any individual taxon within the community to host physiology is made complex due to the diversity and individuality of the gut microbiota. Defined microbial communities such as the Altered Schaedler Flora (ASF) help alleviate the challenges of a diverse microbiota by allowing one to interrogate the relationship between individual bacterial species and host responses. An important aspect of studying these relationships with defined microbial communities is the ability to measure the population abundance and dynamics of each member. Herein, we describe the development of an improved ASF species-specific and sensitive real-time quantitative polymerase chain reaction (qPCR) for use with SYBR Green chemistry to accurately assess individual ASF member abundance. This approach targets hypervariable regions V1 through V3 of the 16S rRNA gene of each ASF taxon to enhance assay specificity. We demonstrate the reproducibility, sensitivity and application of this new method by quantifying each ASF bacterium in two inbred mouse lines. We also used it to assess changes in ASF member abundance before and after acute antibiotic perturbation of the community as well as in mice fed two different diets. Additionally, we describe a nested PCR assay for the detection of lowly abundant ASF members. Altogether, this improved qPCR method will facilitate gnotobiotic research involving the ASF community by allowing for reproducible quantification of its members under various physiological conditions