Preserving Trustworthiness and Confidentiality for Online Multimedia

Technology advancements in areas of mobile computing, social networks, and cloud computing have rapidly changed the way we communicate and interact. The wide adoption of media-oriented mobile devices such as smartphones and tablets enables people to capture information in various media formats, and offers them a rich platform for media consumption. The proliferation of online services and social networks makes it possible to store personal multimedia collection online and share them with family and friends anytime anywhere. Considering the increasing impact of digital multimedia and the trend of cloud computing, this dissertation explores the problem of how to evaluate trustworthiness and preserve confidentiality of online multimedia data. The dissertation consists of two parts. The first part examines the problem of evaluating trustworthiness of multimedia data distributed online. Given the digital nature of multimedia data, editing and tampering of the multimedia content becomes very easy. Therefore, it is important to analyze and reveal the processing history of a multimedia document in order to evaluate its trustworthiness. We propose a new forensic technique called ``Forensic Hash", which draws synergy between two related research areas of image hashing and non-reference multimedia forensics. A forensic hash is a compact signature capturing important information from the original multimedia document to assist forensic analysis and reveal processing history of a multimedia document under question. Our proposed technique is shown to have the advantage of being compact and offering efficient and accurate analysis to forensic questions that cannot be easily answered by convention forensic techniques. The answers that we obtain from the forensic hash provide valuable information on the trustworthiness of online multimedia data. The second part of this dissertation addresses the confidentiality issue of multimedia data stored with online services. The emerging cloud computing paradigm makes it attractive to store private multimedia data online for easy access and sharing. However, the potential of cloud services cannot be fully reached unless the issue of how to preserve confidentiality of sensitive data stored in the cloud is addressed. In this dissertation, we explore techniques that enable confidentiality-preserving search of encrypted multimedia, which can play a critical role in secure online multimedia services. Techniques from image processing, information retrieval, and cryptography are jointly and strategically applied to allow efficient rank-ordered search over encrypted multimedia database and at the same time preserve data confidentiality against malicious intruders and service providers. We demonstrate high efficiency and accuracy of the proposed techniques and provide a quantitative comparative study with conventional techniques based on heavy-weight cryptography primitives

The spatial and temporal characterization of hepatic macrophages during acute liver injury

La réponse immunitaire est régulée spatialement et temporellement. Les cellules immunitaires font partie d’une plus grande communauté de populations cellulaires interconnectées qui coordonnent leurs actions par la signalisation intercellulaire. Suivant une blessure hépatique, la distribution et la composition du compartiment immunitaire évoluent rapidement au fil du temps. Par conséquent, l’information sur la position des cellules immunitaires dans le tissu hépatique est essentielle à la bonne compréhension de leurs fonctions dans la santé et la maladie. Cependant, l’organisation spatiale des cellules immunitaires en réponse à une atteinte hépatique aiguë, ainsi que les conséquences fonctionnelles de leur distribution topographique spécifique, restent mal comprises. Les macrophages hépatiques sont des cellules effectrices clés pendant l’homéostasie et en réponse à des blessures, et sont impliqués dans la pathogenèse de plusieurs maladies du foie. L’hétérogénéité et plasticité des macrophages dans le foie a été exposée avec l’émergence du séquençage de l’ARN, la cytométrie en flux et la cytométrie de masse. Ces techniques ont sensiblement contribué à la compréhension de l’origine, et fonctions des macrophages dans le foie. Cependant, ces technologies impliquent la destruction du tissu pour la préparation de suspension cellulaires ce qui entraîne une perte d’information spatiale et de contexte tissulaire. Par conséquent, la caractérisation spatiale et temporelle des macrophages dans le tissu hépatique pendant l’homéostasie tissulaire, et en réponse à une blessure, fournit une nouvelle information sur la façon dont les macrophages se rapportent aux cellules voisines et leur comportement pendant les réponses immunitaires. Dans la première partie de cette étude, nous avons conçu une stratégie pour le phénotypage spatial des cellules immunitaires hépatiques dans des échantillons de tissus. Cette stratégie combine techniques d'imagerie et l’alignement numérique des images pour surmonter les limitations actuelles du nombre de marqueurs pouvant être visualisés simultanément. En outre, nous avons généré des protocoles pour la quantification automatisée des cellules d’intérêt dans des sections de tissus pour réduire la subjectivité associée à la quantification par inspection visuelle, et pour augmenter la surface et la vitesse de l’analyse. Par conséquent, un plus grand nombre de populations de cellules immunitaires ont été visualisées, quantifiées et cartographiées, et leurs relations spatiales ont été déterminées. Dans la deuxième partie de l’étude, nous avons déterminé la cinétique et la dynamique spatiale des cellules de Kupffer (KCs) et des macrophages dérivés de monocytes (MoMFs) en réponse à une atteinte hépatique aiguë au CCl4, afin de mieux comprendre leurs rôles fonctionnels, et la répartition du travail entre eux. Nous avons constaté que les KC et les MoMFs présentent des différences au niveau de la distribution tissulaire, la morphologie, et la cinétique. En plus, seulement les KCs ont proliféré pour repeupler la population de macrophages résidents pendant la réparation tissulaire. Finalement, nous avons montré que le degré de colocalization de KCs et des MoMFs avec les cellules stellaires est différent. En plus, cette colocalisation varie avec la progression de la réponse immunitaire. Dans l’ensemble, nous avons montré que les KCs et les MoMFs ont des profils spatiaux et temporels différents en réponse à une atteinte hépatique aiguë. Dans l’ensemble, les observations faites dans cette étude suggèrent que le comportement spatial et temporel d’une sous-population donnée de cellules immunitaires est distinct et sous-tend sa capacité à remplir ses fonctions spécifiques pendant la réponse immunitaire.The immune response is spatially and temporally regulated. Immune cells are part of a larger community of interconnected immune and non-immune cell populations that coordinate their actions mostly through cell-cell intercellular signaling. In the liver, the distribution pattern, and the composition of the immune compartment evolve during an immune response to injury influencing disease pathology, progression, and response to treatment. Hence, information on the location and interacting partners of immune cells in the hepatic tissue is critical for the proper understanding of their functions in health and disease. However, the spatial organization of hepatic resident and infiltrating immune cells in response to acute injury, and the functional consequences of their specific topographical distribution, remain poorly defined. Hepatic macrophages are key effector cells during homeostasis and in response to injury and are involved in the pathogenesis of several liver diseases. The heterogeneity and plasticity of the macrophage compartment in the liver have only recently started to be appreciated with the emergence of RNA sequencing, flow cytometry, and mass cytometry. Detailed transcriptomic and phenotypic profiling have deeply expanded our understanding of macrophage biology. However, these technologies involve tissue disruption with loss of spatial information and tissue context. Therefore, the spatial and temporal profiling of liver macrophages in tissue samples during the steady state, and in response to injury, provide novel information on how the macrophages relate to neighboring cells and their behavior during immune responses. In the first part of this study, we designed a strategy for the spatial phenotyping of hepatic immune cells in tissue samples. This strategy combined serial and sequential labeling, and digital tissue alignment to overcome current limitations in the number of markers that can be simultaneously visualized. In addition, we generated protocols for automated quantification of cells of interest in whole tissue sections which removed the subjectivity associated with quantification by visual inspection and greatly increased the area and the speed of the analysis. As a result, a larger number of immune cell populations were visualized, quantified, and mapped, and their spatial relations were determined in an unbiased manner. In the second part of this study, we monitored the kinetics, and spatial dynamics of resident Kupffer cells (KCs) and infiltrating monocyte-derived macrophages (MoMFs) in response to acute liver injury with CCl4, to gain insight into their functional roles, and the distribution of labor between them. KCs and MoMFs exhibited different tissue distribution patterns and cell morphology, different kinetics, and occupied neighboring but unique microanatomical tissue locations. KCs and MoMFs displayed a different capacity to replenish the macrophage pool upon acute injury, and were differentially related to hepatic stellate cells. Different kinetics and spatial profiles revealed that KCs and MoMFs have distinct spatial signatures and suggest that they perform distinct functions during the wound-healing response to acute liver injury. In summary, we optimized techniques and put together a strategy for the spatial profiling of hepatic immune cells. Then, we used this methodology to profile resident and infiltrating macrophage subpopulations to gain insight into their biology and distinct contribution to healing in response to acute liver injury. Overall, the observations made in this study suggest that the spatial and temporal behavior of a given subpopulation of immune cells underlie its ability to perform its specific functions during the immune response

Biometric Systems

Because of the accelerating progress in biometrics research and the latest nation-state threats to security, this book's publication is not only timely but also much needed. This volume contains seventeen peer-reviewed chapters reporting the state of the art in biometrics research: security issues, signature verification, fingerprint identification, wrist vascular biometrics, ear detection, face detection and identification (including a new survey of face recognition), person re-identification, electrocardiogram (ECT) recognition, and several multi-modal systems. This book will be a valuable resource for graduate students, engineers, and researchers interested in understanding and investigating this important field of study

Registration of histology and magnetic resonance imaging of the brain

Combining histology and non-invasive imaging has been attracting the attention of the medical imaging community for a long time, due to its potential to correlate macroscopic information with the underlying microscopic properties of tissues. Histology is an invasive procedure that disrupts the spatial arrangement of the tissue components but enables visualisation and characterisation at a cellular level. In contrast, macroscopic imaging allows non-invasive acquisition of volumetric information but does not provide any microscopic details. Through the establishment of spatial correspondences obtained via image registration, it is possible to compare micro- and macroscopic information and to recover the original histological arrangement in three dimensions. In this thesis, I present: (i) a survey of the literature relative to methods for histology reconstruction with and without the help of 3D medical imaging; (ii) a graph-theoretic method for histology volume reconstruction from sets of 2D sections, without external information; (iii) a method for multimodal 2D linear registration between histology and MRI based on partial matching of shape-informative boundaries

Uncovering the Mechanisms Underpinning Melanoma Invasiveness at Single Cell Resolution

Metastatic cancer is responsible for 90% of cancer-related deaths, and a lack of effective therapies has seen survival rates remain bleak. Solid cancer cells escape the primary tumour mass and acquire invasive potential through an epithelial to mesenchymal transition (EMT), regulated by a set of master transcription factors (TFs) known as EMT-TFs. EMT-TF activity is in turn controlled by interacting signalling pathways, including the TGFß, Wnt and NF- κB pathways, which become dysregulated in cancer. Once escaped, metastatic cancer cells employ interchangeable modes of migration, transitioning between fibroblast-like mesenchymal migration and amoeboid migration, where cells display a rounded morphology and navigate the extracellular matrix in a protease independent manner. However, the key molecules that orchestrate the switch between mesenchymal and amoeboid migratory modes remain incompletely understood. This thesis describes a novel 3D spheroid invasion assay and single cell isolation technique that provides detailed 3D data on growth and invasion, and allows for the specific isolation of cells of a given phenotype. Via the expression of a photoconvertible fluorescent protein, compact epithelial cells at the edge of a tumour mass, elongated cells in the process of leaving the mass, and rounded amoeboid cells migrating away from the mass were tagged for isolation. Photoconverted cells were then single-cell sorted by flow cytometry and subjected to paired-end Illumina single cell RNA sequencing. 463 differentially expressed genes were identified via DESeq2 and enriched pathways determined by GSEA analysis. Delta opioid receptor and folate transporter SLC19A1 expression were upregulated in amoeboid migration and their functions investigated via pharmacological perturbation, while INKA1 expression was downregulated in amoeboid cells and its function investigated via inducible overexpression. This work describes a novel, adaptable and readily implementable method for the analysis of the earliest phases of cancer cell invasion, and its application to the identification of genes underpinning the invasiveness of malignant melanoma

Using MapReduce Streaming for Distributed Life Simulation on the Cloud

Distributed software simulations are indispensable in the study of large-scale life models but often require the use of technically complex lower-level distributed computing frameworks, such as MPI. We propose to overcome the complexity challenge by applying the emerging MapReduce (MR) model to distributed life simulations and by running such simulations on the cloud. Technically, we design optimized MR streaming algorithms for discrete and continuous versions of Conway’s life according to a general MR streaming pattern. We chose life because it is simple enough as a testbed for MR’s applicability to a-life simulations and general enough to make our results applicable to various lattice-based a-life models. We implement and empirically evaluate our algorithms’ performance on Amazon’s Elastic MR cloud. Our experiments demonstrate that a single MR optimization technique called strip partitioning can reduce the execution time of continuous life simulations by 64%. To the best of our knowledge, we are the first to propose and evaluate MR streaming algorithms for lattice-based simulations. Our algorithms can serve as prototypes in the development of novel MR simulation algorithms for large-scale lattice-based a-life models.https://digitalcommons.chapman.edu/scs_books/1014/thumbnail.jp

Atherosclerosis: Methods and Protocols

This volume provides detailed, up-to-date methods used in research on Atherosclerosis. Chapters guide readers through an overview of the pathogenesis of atherosclerosis and model systems together with in vitro, ex vivo, in vivo and emerging methods in atherosclerosis research. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, Atherosclerosis: Methods and Protocols serves as an invaluable resource for those engaging in research on atherosclerosis and cardiovascular disease, as well as for researchers who are new to t