Zero-padding Network Coding and Compressed Sensing for Optimized Packets Transmission

Ubiquitous Internet of Things (IoT) is destined to connect everybody and everything on a never-before-seen scale. Such networks, however, have to tackle the inherent issues created by the presence of very heterogeneous data transmissions over the same shared network. This very diverse communication, in turn, produces network packets of various sizes ranging from very small sensory readings to comparatively humongous video frames. Such a massive amount of data itself, as in the case of sensory networks, is also continuously captured at varying rates and contributes to increasing the load on the network itself, which could hinder transmission efficiency. However, they also open up possibilities to exploit various correlations in the transmitted data due to their sheer number. Reductions based on this also enable the networks to keep up with the new wave of big data-driven communications by simply investing in the promotion of select techniques that efficiently utilize the resources of the communication systems. One of the solutions to tackle the erroneous transmission of data employs linear coding techniques, which are ill-equipped to handle the processing of packets with differing sizes. Random Linear Network Coding (RLNC), for instance, generates unreasonable amounts of padding overhead to compensate for the different message lengths, thereby suppressing the pervasive benefits of the coding itself. We propose a set of approaches that overcome such issues, while also reducing the decoding delays at the same time. Specifically, we introduce and elaborate on the concept of macro-symbols and the design of different coding schemes. Due to the heterogeneity of the packet sizes, our progressive shortening scheme is the first RLNC-based approach that generates and recodes unequal-sized coded packets. Another of our solutions is deterministic shifting that reduces the overall number of transmitted packets. Moreover, the RaSOR scheme employs coding using XORing operations on shifted packets, without the need for coding coefficients, thus favoring linear encoding and decoding complexities. Another facet of IoT applications can be found in sensory data known to be highly correlated, where compressed sensing is a potential approach to reduce the overall transmissions. In such scenarios, network coding can also help. Our proposed joint compressed sensing and real network coding design fully exploit the correlations in cluster-based wireless sensor networks, such as the ones advocated by Industry 4.0. This design focused on performing one-step decoding to reduce the computational complexities and delays of the reconstruction process at the receiver and investigates the effectiveness of combined compressed sensing and network coding

Intelligent Sensor Networks

In the last decade, wireless or wired sensor networks have attracted much attention. However, most designs target general sensor network issues including protocol stack (routing, MAC, etc.) and security issues. This book focuses on the close integration of sensing, networking, and smart signal processing via machine learning. Based on their world-class research, the authors present the fundamentals of intelligent sensor networks. They cover sensing and sampling, distributed signal processing, and intelligent signal learning. In addition, they present cutting-edge research results from leading experts

Standardization of innovative cardiovascular magnetic resonance sequences - Evaluating the reproducibility of different vendors and field strengths

Die kardiovaskuläre MRT (CMR) ist als nicht-invasives Verfahren zur Diagnostik kardiovaskulärer Erkrankungen bereits in die aktuellen Leitlinien integriert. Durch die Entwicklung innovativer Sequenzen konnte das Spektrum klinischer Indikationen in den letzten Jahren zunehmend erweitert werden. Die dreidimensionale zeitaufgelöste Phasenkontrast-MRT (4D-Fluss-MRT) kann durch die Quantifizierung und Visualisierung kardialer Hämodynamik einen wichtigen Beitrag zum Verständnis kardiovaskulärer Pathophysiologie sowie zur Diagnostik und Therapiesteuerung von Erkrankungen leisten. Fast Strain-encoding (fSENC) ermöglicht als neue Methode die Erfassung myokardialen Strains innerhalb weniger Sekunden. Der Transfer dieser Sequenzen in die klinische Routine erfordert ein Bewusstsein für Störfaktoren. Ziel dieser Arbeit ist die Evaluation potenzieller Störfaktoren wie unterschiedliche MRTHersteller oder Feldstärken als Beitrag zur Standardisierung innovativer CMRSequenzen. 15 gesunde Proband*innen wurden mittels 4D-Fluss-MRT an 3T-Scannern dreier verschiedener Hersteller (GE, Philips, Siemens) untersucht. Als hämodynamische Vergleichsparameter wurden Vorwärtsflussvolumen, maximale Flussgeschwindigkeit und Wandscherkräfte in neun Ebenen bestimmt (1). Des Weiteren wurde die aortale Hämodynamik von zehn gesunden Proband*innen via 4D-Fluss-MRT an drei verschiedenen Feldstärken (1,5T, 3T, 7T) sowie drei unterschiedlichen Sequenzen am 1,5T-MRT untersucht (2). Die Reproduzierbarkeit der fSENC wurde ebenfalls an drei MRT-Geräten unterschiedlicher Hersteller bei 15 gesunden Proband*innen evaluiert. Zur Strain-Analyse wurden globaler zirkumferentieller Strain und globaler longitudinaler Strain genutzt (3). Zusätzlich wurden Scan-Rescan-Reproduzierbarkeit und Intra- und Interobserver-Variabilität beurteilt (1-3). Die hämodynamischen Parameter in der 4D-Fluss-MRT unterschieden sich signifikant zwischen den Scannern dreier verschiedener Hersteller und überschritten jeweils den durch die Intraobserver-Analyse definierten Äquivalenzbereich (1). Die Darstellung der 4D-Fluss-MRT gelang bei allen Feldstärken mit suffizienter Bildqualität. Die Ergebnisse aller hämodynamischen Parameter waren zwischen den Feldstärken ebenfalls nicht äquivalent (2). In den fSENC-Messungen zeigte sich zwischen den drei MRT-Geräten ein geringer, jedoch statistisch signifikanter Bias (3). Die Scan-Rescan- sowie Intra- und Interobserver-Reproduzierbarkeit erzielten gute bis exzellente Ergebnisse (1-3). Zusammenfassend werden durch die spezifischen Protokolle an MRT-Geräten unterschiedlicher Hersteller oder Feldstärken signifikante Unterschiede in den Ergebnissen innovativer CMR-Sequenzen hervorgerufen. Diese Erkenntnis sollte insbesondere bei der Durchführung multizentrischer Studien und Follow-up-Untersuchungen beachtet werden. Für eine optimierte Etablierung in der klinischen Routine ist eine weitere Standardisierung dieser Sequenzen daher essenziell.Cardiovascular magnetic resonance (CMR) has already been established in current guidelines as a non-invasive method for diagnosis of cardiovascular diseases. The development of innovative sequences has fostered an increase in the range of clinical indications during the past years. Three-dimensional time-resolved phase-contrast magnetic resonance (4D Flow MR) enables quantification and visualization of cardiac hemodynamics and may help in understanding cardiovascular pathophysiology as well as in diagnostics and therapy guiding of diseases. Fast strain-encoding (fSENC) is a novel method that allows the acquisition of myocardial strain within a few seconds. Transferring these sequences into clinical routine requires an awareness of confounders. The aim of this work is the evaluation of potential confounders such as different MRI vendors or field strengths as a contribution to the standardization of innovative CMR sequences. 15 healthy volunteers underwent 4D Flow MR examinations at 3T scanners of three different vendors (GE, Philips, Siemens). Forward flow volume, peak velocity and wall shear stress as hemodynamic parameters were investigated in nine planes (1). Furthermore, the aortic hemodynamics of ten healthy volunteers were examined using 4D Flow MR at three different field strengths (1.5T, 3T, 7T) and three different sequences on 1.5T MRI (2). The reproducibility of fSENC was also evaluated on three scanners from different vendors in 15 healthy volunteers. Global circumferential strain and global longitudinal strain were determined for strain analysis (3). In addition, scan-rescan reproducibility as well as intra- and interobserver variability were examined (1-3). 4D flow derived hemodynamic parameters differed significantly between scanners of the three different vendors and exceeded the equivalence range defined by intraobserveranalysis (1). 4D Flow MR displayed sufficient image quality at all field strengths. The results of all hemodynamic parameters were also non-equivalent between field strengths (2). In the fSENC measurements, there was a slight but statistically significant bias between the three scanners (3). Scan-rescan as well as intra- and interobserver reproducibility yielded good to excellent results (1-3). In summary, specific protocols used at scanners from different vendors or field strengths lead to significant differences in the results of innovative CMR sequences. This finding should be taken into account when conducting multi-center studies or patient’s follow-up examinations. Further standardization of these sequences is essential for implementation in clinical routine

Volume 21, issue 2

The mission of CJS is to contribute to the effective continuing medical education of Canadian surgical specialists, using innovative techniques when feasible, and to provide surgeons with an effective vehicle for the dissemination of observations in the areas of clinical and basic science research. Visit the journal website at http://canjsurg.ca/ for more.https://ir.lib.uwo.ca/cjs/1153/thumbnail.jp

Life Sciences Program Tasks and Bibliography for FY 1997

This document includes information on all peer reviewed projects funded by the Office of Life and Microgravity Sciences and Applications, Life Sciences Division during fiscal year 1997. This document will be published annually and made available to scientists in the space life sciences field both as a hard copy and as an interactive internet web page

Highly Sensitive, Stretchable and Durable Sensors Based on Conductive Polymer Hydrogels

In recent years, wearable sensor devices, which directly attach to human skin for precise and dynamic human motion and physiological signals monitoring, have experienced a rapid development and presented a great use in modern medical systems. Despite the great research progress, the wearable sensors often need synchronized deformation of conductive fillers and flexible substrates to enable the mechanical signals transformation. However, some of the matrices are not flexible and stretchable enough, thus constraining the sensitivity and high precision of devices. Therefore, a stretchable, durable, and highly sensitive material was urgently needed. In this light, conductive hydrogels, offering the advantages of good flexibility, stretchability and biocompatibility, have attracted great interest as body-worn sensors. Additionally, hydrogels enjoy the capacity of tuning their mechanical properties to perfectly match with human skin. Therefore, a large number of stretchable hydrogel-based sensors has been fabricated. However, only a few hydrogel sensors can widely realize commercial application, with insufficient mechanical strength and stretchability as one of the main reasons. In addition, the sensing performance is not satisfactory. Particularly, it is difficult to detect some subtle deformations due to easy interference by external environment, thus leading to poor long-term durability. In this thesis, a novel one-pot technique to synthesize ultrastretchable hydrogel-based strain sensors by integrating carbon nanofibers with a double-network hydrogel matrix was reported. Outstanding mechanical properties of Agar/polyacrylamide(PAAm) double-network (DN) hydrogel, combing with high strain sensitivity given by tunneling effect of carbon nanomaterials, enable it to be a durable human motion sensor. We also prepare a highly anisotropic nanofluidic ionic skin (ANIS) composing of polyvinyl alcohol (PVA) and cellulose nanofibril via thermal stretching method, displaying comparable modulus, higher fracture energy and anti-fatigue property with cartilage and skin. It shows good pressure-independent temperature sensing property. Additionally, anisotropic and ionic conductive PVA/poly(N-isopropylacrylamide) (PNIPAM) DN hydrogel films with both physically and chemically cross-linked networks are created for multifunctional devices via thermal stretching, immersing and etching method. Combining the strong mechanical property of PVA under prestretching and unique thermal sensitivity of PNIPAM, PVA/PNIPAM DN gel can be ideal candidate for multiple sensing upon strain, pressure and temperature

The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry

The 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry was held on 1–15 July 2021. The scope of this online conference was to gather experts that are well-known worldwide who are currently working in chemical sensor technologies and to provide an online forum for the presention and discussion of new results. Throughout this event, topics of interest included, but were not limited to, the following: electrochemical devices and sensors; optical chemical sensors; mass-sensitive sensors; materials for chemical sensing; nano- and micro-technologies for sensing; chemical assays and validation; chemical sensor applications; analytical methods; gas sensors and apparatuses; electronic noses; electronic tongues; microfluidic devices; lab-on-a-chip; single-molecule sensing; nanosensors; and medico-diagnostic testing