Compressed RF tomography: centralized and decentralized approaches

Radio Frequency (RF) tomography refers to the process of inferring information about the contents of an environment via capturing and analyzing transmitted RF signals. Received Signal Strength (RSS) measurements acquired by the sensor nodes are analyzed to determine the location of certain obstructions in the environment. Therefore, a wireless sensor network can employ RF tomography for surveillance and monitoring in a environment. In this thesis, we introduce Compressed RF Tomography for monitoring via wireless sensor nodes, which requires fewer RSS measurements than non-compressed RF tomography, allowing for an extended network lifetime. Compressed sensing is a recent field of research that has captured considerable attention in engineering due to its efficiency in signal sampling. Combined with RF tomography, it introduces a new approach to monitoring in wireless sensor networks. Our main contributions in this work include employing compressive sensing techniques in RF tomographic imaging, and demonstrating their capabilities in centralized and decentralized processing schemes. We present an approach that uses battery power more efficiently and performs better when only few sensors are available. Moreover, we introduce decentralized schemes for in-network data analysis. This allows sensors to cooperatively monitor the environment without the need for a fusion center. Simulations throughout the thesis illustrate the performance of our approach under different situations. Real sensor network data is also used to compare our approaches with the existing approach.La tomographie par radio-fréquence (RF) se réfère au processus de déduire des informations sur le contenu d'un environnement via la conquête et l'analyse de signaux de la radio-fréquence transmise. La force du signal reçu mesurée acquises par les noeuds de capteur est analysée pour déterminer l'emplacement de certaines obstructions dans l'environnement. Donc, un réseau de capteur sans fil peut employer la tomographie par radio-fréquence pour la surveillance et le contrôle dans un environnement. Dans cette thèse, nous présentons la tomographie par radio-fréquence compressé pour contrôler via des noeuds de capteur sans fil, qui exigent moins de force du signal reçu que des mesures que la tomographie par radio-fréquence non-compressée, tenant compte d'une durée de fonctionnement de réseau étendue. La notion d'Acquisition Comprimée est un domaine récent de la recherche qui a capté une attention considérable dans l'ingénierie en raison de son efficacité dans l'échantillonnage de signal. Combiné avec la tomographie par radio-fréquence, il présente une nouvelle approche au contrôle dans des réseaux de capteur sans fil. Nos contributions principales dans ce travail incluent des techniques de notions compressives employées dans les images de tomographie par radio-fréquence, démontrant leurs capacités dans des arrangements centralisés. Nous présentons une approche qui utilise le pouvoir d'une batterie plus efficace et opère mieux alors que seulement peu de capteurs sont requis. De plus, nous présentons des arrangements décentralisés pour l'analyse de données en réseau. Cela permet aux capteurs de coopérativement contrôler l'environnement sans le besoin d'un centre de fusion. Les simulations dans la thèse illustrent la performance de notre approche dans différentes situations. Des données de réseau de capteurs réels ont été aussi utilisées pour comparer

A Linear Algebraic Threshold Essential Secret Image Sharing Scheme

A secret sharing scheme allocates to each participant a share of a secret in such a way that authorized subsets of participants can reconstruct the secret, while shares of unauthorized subsets of participants provide no useful information about the secret. For positive integers r,s,t,n with r⩽s⩽t⩽n, an (r,s,t,n)–threshold essential secret sharing scheme is an algorithm that decomposes a secret S into n shares, s of which are essential, in a way that authorized subsets are precisely those with at least t members, at least r of whom are essential. This work proposes a lossless linear algebraic (r,s,t,n)–threshold essential secret image sharing scheme that decomposes the secret, S, into equally-sized shares, each of size 1/t the size of S. For each block, B, of S, the scheme assigns to the n participants distinct signature vectors v1,v2,…,vn in the vector space F2αt, where α is a suitable positive integer, typically between 2 and 5, inclusive. These signature vectors must adhere to some admissibility conditions in order to satisfy the secret sharing threshold properties. The decomposition of B into n shares is obtained by partitioning B into t vectors, then computing the share yj of the jth participant (1≤j≤n), as a linear combination of these parts with coefficients from the signature vj. The presented simulations showcase the effectiveness and robustness of the proposed scheme against standard statistical and security attacks. They further demonstrate its superiority with respect to existing schemes

A Probabilistic Chaotic Image Encryption Scheme

This paper proposes a probabilistic image encryption scheme that improves on existing deterministic schemes by using a chaining mode of chaotic maps in a permutation-masking process. Despite its simplicity, the permutation phase destroys any correlation between adjacent pixel values in a meaningful image. The masking phase, however, modifies the pixel values of the image at hand using pseudorandom numbers with some other initiated random numbers so that any slight change in the plain image spreads throughout the corresponding cipher image. These random numbers ensure the generation of distinct cipher images for the same plain image encryption, even if it is encrypted multiple times with the same key, thereby adding some security features. Simulations show that the proposed scheme is robust to common statistical and security threats. Furthermore, the scheme is shown to be competitive with existing image encryption schemes

Autosomal dominant polycystic kidney disease and minimal trauma: medical review and case report

Abstract Background Blunt abdominal trauma in the setting of polycystic kidney disease is still scantly described in the literature and management guidelines of such patients are not well-established. Case presentation The authors herein present a case of hypovolemic shock secondary to segmental renal artery bleed in a 75-year-old man with polycystic kidney disease after minimal blunt abdominal trauma, who underwent successful selective arterial embolization, and provide a thorough review of similar cases in the literature, while shedding the light on important considerations when dealing with such patients. Conclusions It is important to suspect renal injury in patients with pre-existing renal lesions irrespective of the mechanism of injury; and, vice-versa to suspect an underlying abnormality in patients with a clinical deterioration that’s out of proportion to the mechanism of injury

Data from: Outcomes of systolic heart failure patients presenting with sepsis to the emergency department of a tertiary hospital: a retrospective chart review study from Lebanon

Objectives: Congestive heart failure (CHF) patients may be at a higher risk of mortality from sepsis than patients without CHF due to insufficient cardiovascular reserves during systemic infections. . The aim of this study is to compare sepsis-related mortality between CHF and non-CHF patients in patients presenting to a tertiary medical center. Design: A single centre, retrospective, cohort study. Setting: Conducted in an academic ED between January 2010 and January 2015. Patients’ charts were queried via the hospital’s electronic system. Patients with a diagnosis of sepsis were included. Descriptive analysis was performed on the demographics, characteristics, and outcomes of septic patients of the study population. Participants: A total of 174 patients, of which 87 (50%) were CHF patients. Primary and secondary outcomes: The primary outcome of the study was in-hospital mortality. Secondary outcomes included intensive care unit (ICU), and hospital lengths of stay, and differences in interventions between the two groups. Results: CHF patients had a higher in-hospital mortality (57.5% vs 34.5%). Septic CHF patients had higher odds of death as compared to the control population (OR, 2.45; 95% CI, 1.22-4.88). Secondary analyses showed that CHF patients had lower instances of bacteremia upon presentation to the ED (31.8% vs 46.4%). They had less IV fluid requirements in first 24 hours (2.75 ± 2.28 L vs 3.67 ± 2.82 L, p-value=0.038), had a higher rate of intubation in the ED (24.2% vs 10.6%, p-value=0.025) and required more dobutamine in the first 24 hours (16.1% vs 1.1%, p-value<0.001). Emergency department length of stay was found to be lower in CHF patients (15.12 ± 24.45 hours vs 18.17 ± 26.13 hours, p-value=0.418) and they were more likely to be admitted to the ICU (59.8% vs 48.8%, p-value=0.149). Conclusion: Septic patients with CHF experienced an increased hospital mortality compared to patients without CHF

Data_heart_failure

Raw data of the systolic heart failure and sepsi