152 research outputs found
Hybrid Satellite-Terrestrial Communication Networks for the Maritime Internet of Things: Key Technologies, Opportunities, and Challenges
With the rapid development of marine activities, there has been an increasing
number of maritime mobile terminals, as well as a growing demand for high-speed
and ultra-reliable maritime communications to keep them connected.
Traditionally, the maritime Internet of Things (IoT) is enabled by maritime
satellites. However, satellites are seriously restricted by their high latency
and relatively low data rate. As an alternative, shore & island-based base
stations (BSs) can be built to extend the coverage of terrestrial networks
using fourth-generation (4G), fifth-generation (5G), and beyond 5G services.
Unmanned aerial vehicles can also be exploited to serve as aerial maritime BSs.
Despite of all these approaches, there are still open issues for an efficient
maritime communication network (MCN). For example, due to the complicated
electromagnetic propagation environment, the limited geometrically available BS
sites, and rigorous service demands from mission-critical applications,
conventional communication and networking theories and methods should be
tailored for maritime scenarios. Towards this end, we provide a survey on the
demand for maritime communications, the state-of-the-art MCNs, and key
technologies for enhancing transmission efficiency, extending network coverage,
and provisioning maritime-specific services. Future challenges in developing an
environment-aware, service-driven, and integrated satellite-air-ground MCN to
be smart enough to utilize external auxiliary information, e.g., sea state and
atmosphere conditions, are also discussed
Western Prairie Fringed Orchid Management, Ecology, and Decline at Mormon Island
The western prairie fringed orchid (Platanthera praeclara Sheviak & M. L. Bowles; WPFO) was first detected in a vegetative state on Mormon Island in 1978 and identification was confirmed following a mass flowering event in 1982. From a high count of ~60 plants the WPFO slowly declined and has not been observed since 2000 despite flowering season surveys conducted in 15 of the last 20 years. We explore the natural history of the WPFO in the contexts of Mormon Island to establish potential causes for its apparent disappearance and evaluate the possibility it persists in some capacity. Our investigation of secondary data suggests the Mormon Island vegetation community remains relatively intact, including species associated with WPFO occurrence. Examination of the ranges of known and potential WPFO pollinators suggests that Sphinx drupiferarum, Eumorpha achemon, and Hyles lineata were the most likely pollinators at Mormon Island, and recent observations of these species indicate pollinator decline may not have been a primary factor in WPFO disappearance locally. Research demonstrates individual WPFOs can occasionally live for decades, are able to survive underground as rhizomes for periods of time, and often present above ground as just 1â3 leaves during the growing season. Additionally, the seeds may persist in the soil for a substantial period of time. The WPFO appears to tolerate a reasonably wide range of habitat conditions and management regimes but may require a relatively narrow range of circumstances to flower en masse, including above average spring precipitation in subsequent years. Mass flowering events may also be stimulated by early spring burns that precede above ground vegetative growth and subsequent rest during the growing season, but research is equivocal. Though factors such as inbreeding depression and herbicide overspray could have potentially impacted the population, based on local conditions we suggest the WPFO may persist on Mormon Island in a reduced capacity. We recommend the continuation of growing season surveys and experimentation with multi-year management strategies that could stimulate growth and flowering
Whereâs the risk? Landscape epidemiology of gastrointestinal parasitism in Alberta beef cattle
Sherpa Romeo green journal; open accessBackground: Gastrointenstinal nematodes (GIN) present a serious challenge to the health and productivity of
grazing stock around the globe. However, the epidemiology of GIN transmission remains poorly understood in
northern climates. Combining use of serological diagnostics, GIS mapping technology, and geospatial statistics, we
evaluated ecological covariates of spatial and temporal variability in GIN transmission among bovine calves
pastured in Alberta, Canada.
Methods: Sera were collected from 1000 beef calves across Alberta, Canada over three consecutive years (2008â2010)
and analyzed for presence of anti-GIN antibodies using the SVANOVIR Ostertagia osteragi-Ab ELISA kit. Using a GIS and
Bayesian multivariate spatial statistics, we evaluated the degree to which variation in specific environmental covariates
(e.g. moisture, humidity, temperature) was associated with variation in spatial and temporal heterogeneity in exposure
to GIN (Nematodirus and other trichostrongyles, primarily Ostertagia and Cooperia).
Results: Variation in growing degree days above a base temperature of 5 °C, humidity, air temperature, and
accumulated precipitation were found to be significant predictors of broadâscale spatial and temporal variation in
serum antibody concentrations. Risk model projections identified that while transmission in cattle from southeastern
and northwestern Alberta was relatively low in all years, rate of GIN transmission was generally higher in the central
region of Alberta.
Conclusions: The spatial variability in risk is attributed to higher average humidity, precipitation and moderate
temperatures in the central region of Alberta in comparison with the hot, dry southeastern corner of the province and
the cool, dry northwestern corner. Although more targeted sampling is needed to improve model accuracy, our
projections represent an important step towards tying treatment recommendations to actual risk of infection.Ye
Engineering Design and Optimization of Large-Scale Solar Photovoltaic and Wind Turbine Installation in an Urban Environment
Wind turbine and photovoltaic (PV) technologies will play a significant role in the world energy future. However, a lack of awareness of the potential of renewables is a significant challenge in sustainable energy development. The potential of solar and wind energy sources in producing electricity to meet the electrical demands of the University of Lethbridge was evaluated. Furthermore, expanding the research to a large area, a multi-criteria approach based on geographic information systems (GIS) and light detection and ranging (LiDAR) was developed to estimate rooftop photovoltaic potential of buildings in an urban environment, the City of Lethbridge. The unreliability of renewable resources is an impediment to developing renewable projects. An optimal sizing strategy was developed using a particle swarm optimization (PSO) technique to determine the optimum configuration of photovoltaic panels, wind turbines and battery units minimizing the annual system cost while maximizing the reliability of the hybrid system.The University of Lethbridge,
The Mitacs Program (Canada), in cooperation with NOVUS Environmental, Guelph, Ontari
Big Data Computing for Geospatial Applications
The convergence of big data and geospatial computing has brought forth challenges and opportunities to Geographic Information Science with regard to geospatial data management, processing, analysis, modeling, and visualization. This book highlights recent advancements in integrating new computing approaches, spatial methods, and data management strategies to tackle geospatial big data challenges and meanwhile demonstrates opportunities for using big data for geospatial applications. Crucial to the advancements highlighted in this book is the integration of computational thinking and spatial thinking and the transformation of abstract ideas and models to concrete data structures and algorithms
Self-organizing Network Optimization via Placement of Additional Nodes
Das Hauptforschungsgebiet des Graduiertenkollegs "International Graduate
School on Mobile Communication" (GS Mobicom) der Technischen UniversitÀt
Ilmenau ist die Kommunikation in Katastrophenszenarien. Wegen eines
Desasters oder einer Katastrophe können die terrestrischen Elementen der
Infrastruktur eines Kommunikationsnetzwerks beschÀdigt oder komplett
zerstört werden. Dennoch spielen verfĂŒgbare Kommunikationsnetze eine sehr
wichtige Rolle wĂ€hrend der RettungsmaĂnahmen, besonders fĂŒr die
Koordinierung der Rettungstruppen und fĂŒr die Kommunikation zwischen ihren
Mitgliedern. Ein solcher Service kann durch ein mobiles Ad-Hoc-Netzwerk
(MANET) zur VerfĂŒgung gestellt werden. Ein typisches Problem der MANETs
ist Netzwerkpartitionierung, welche zur Isolation von verschiedenen
Knotengruppen fĂŒhrt. Eine mögliche Lösung dieses Problems ist die
Positionierung von zusÀtzlichen Knoten, welche die Verbindung zwischen den
isolierten Partitionen wiederherstellen können. Hauptziele dieser Arbeit
sind die Recherche und die Entwicklung von Algorithmen und Methoden zur
Positionierung der zusÀtzlichen Knoten. Der Fokus der Recherche liegt auf
Untersuchung der verteilten Algorithmen zur Bestimmung der Positionen fĂŒr
die zusÀtzlichen Knoten. Die verteilten Algorithmen benutzen nur die
Information, welche in einer lokalen Umgebung eines Knotens verfĂŒgbar ist,
und dadurch entsteht ein selbstorganisierendes System. Jedoch wird das
gesamte Netzwerk hier vor allem innerhalb eines ganz speziellen Szenarios -
Katastrophenszenario - betrachtet. In einer solchen Situation kann die
Information ĂŒber die Topologie des zu reparierenden Netzwerks im Voraus
erfasst werden und soll, natĂŒrlich, fĂŒr die Wiederherstellung mitbenutzt
werden. Dank der eventuell verfĂŒgbaren zusĂ€tzlichen Information können
die Positionen fĂŒr die zusĂ€tzlichen Knoten genauer ermittelt werden. Die
Arbeit umfasst eine Beschreibung, Implementierungsdetails und eine
Evaluierung eines selbstorganisierendes Systems, welche die
Netzwerkwiederherstellung in beiden Szenarien ermöglicht.The main research area of the International Graduate School on Mobile
Communication (GS Mobicom) at Ilmenau University of Technology is
communication in disaster scenarios. Due to a disaster or an accident, the
network infrastructure can be damaged or even completely destroyed.
However, available communication networks play a vital role during the
rescue activities especially for the coordination of the rescue teams and
for the communication between their members. Such a communication service
can be provided by a Mobile Ad-Hoc Network (MANET). One of the typical
problems of a MANET is network partitioning, when separate groups of nodes
become isolated from each other. One possible solution for this problem is
the placement of additional nodes in order to reconstruct the communication
links between isolated network partitions. The primary goal of this work is
the research and development of algorithms and methods for the placement of
additional nodes. The focus of this research lies on the investigation of
distributed algorithms for the placement of additional nodes, which use
only the information from the nodesâ local environment and thus form a
self-organizing system. However, during the usage specifics of the system
in a disaster scenario, global information about the topology of the
network to be recovered can be known or collected in advance. In this case,
it is of course reasonable to use this information in order to calculate
the placement positions more precisely. The work provides the description,
the implementation details and the evaluation of a self-organizing system
which is able to recover from network partitioning in both situations
Marshall Space Flight Center Research and Technology Report 2018
Many of NASAs missions would not be possible if it were not for the investments made in research advancements and technology development efforts. The technologies developed at Marshall Space Flight Center contribute to NASAs strategic array of missions through technology development and accomplishments. The scientists, researchers, and technologists of Marshall Space Flight Center who are working these enabling technology efforts are facilitating NASAs ability to fulfill the ambitious goals of innovation, exploration, and discovery
Security and the smart city: A systematic review
The implementation of smart technology in cities is often hailed as the solution to many urban challenges such as transportation, waste management, and environmental protection. Issues of security and crime prevention, however, are in many cases neglected. Moreover, when researchers do introduce new smart security technologies, they rarely discuss their implementation or question how new smart city security might affect traditional policing and urban planning processes. This systematic review explores the recent literature concerned with new âsmart cityâ security technologies and aims to investigate to what extent these new interventions correspond with traditional functions of security interventions. Through an extensive literature search we compiled a list of security interventions for smart cities and suggest several changes to the conceptual status quo in the field. Ultimately, we propose three clear categories to categorise security interventions in smart cities: Those interventions that use new sensors but traditional actuators, those that seek to make old systems smart, and those that introduce entirely new functions. These themes are then discussed in detail and the importance of each group of interventions for the overall field of urban security and governance is assessed
Modeling and Simulation in Engineering
This book provides an open platform to establish and share knowledge developed by scholars, scientists, and engineers from all over the world, about various applications of the modeling and simulation in the design process of products, in various engineering fields. The book consists of 12 chapters arranged in two sections (3D Modeling and Virtual Prototyping), reflecting the multidimensionality of applications related to modeling and simulation. Some of the most recent modeling and simulation techniques, as well as some of the most accurate and sophisticated software in treating complex systems, are applied. All the original contributions in this book are jointed by the basic principle of a successful modeling and simulation process: as complex as necessary, and as simple as possible. The idea is to manipulate the simplifying assumptions in a way that reduces the complexity of the model (in order to make a real-time simulation), but without altering the precision of the results
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