3,034 research outputs found
PluralisMAC: a generic multi-MAC framework for heterogeneous, multiservice wireless networks, applied to smart containers
Developing energy-efficient MAC protocols for lightweight wireless systems has been a challenging task for decades because of the specific requirements of various applications and the varying environments in which wireless systems are deployed. Many MAC protocols for wireless networks have been proposed, often custom-made for a specific application. It is clear that one MAC does not fit all the requirements. So, how should a MAC layer deal with an application that has several modes (each with different requirements) or with the deployment of another application during the lifetime of the system? Especially in a mobile wireless system, like Smart Monitoring of Containers, we cannot know in advance the application state (empty container versus stuffed container). Dynamic switching between different energy-efficient MAC strategies is needed. Our architecture, called PluralisMAC, contains a generic multi-MAC framework and a generic neighbour monitoring and filtering framework. To validate the real-world feasibility of our architecture, we have implemented it in TinyOS and have done experiments on the TMote Sky nodes in the w-iLab.t testbed. Experimental results show that dynamic switching between MAC strategies is possible with minimal receive chain overhead, while meeting the various application requirements (reliability and low-energy consumption)
Continued study of NAVSTAR/GPS for general aviation
A conceptual approach for examining the full potential of Global Positioning Systems (GPS) for the general aviation community is presented. Aspects of an experimental program to demonstrate these concepts are discussed. The report concludes with the observation that the true potential of GPS can only be exploited by utilization in concert with a data link. The capability afforded by the combination of position location and reporting stimulates the concept of GPS providing the auxiliary functions of collision avoidance, and approach and landing guidance. A series of general recommendations for future NASA and civil community efforts in order to continue to support GPS for general aviation are included
On the Security of the Automatic Dependent Surveillance-Broadcast Protocol
Automatic dependent surveillance-broadcast (ADS-B) is the communications
protocol currently being rolled out as part of next generation air
transportation systems. As the heart of modern air traffic control, it will
play an essential role in the protection of two billion passengers per year,
besides being crucial to many other interest groups in aviation. The inherent
lack of security measures in the ADS-B protocol has long been a topic in both
the aviation circles and in the academic community. Due to recently published
proof-of-concept attacks, the topic is becoming ever more pressing, especially
with the deadline for mandatory implementation in most airspaces fast
approaching.
This survey first summarizes the attacks and problems that have been reported
in relation to ADS-B security. Thereafter, it surveys both the theoretical and
practical efforts which have been previously conducted concerning these issues,
including possible countermeasures. In addition, the survey seeks to go beyond
the current state of the art and gives a detailed assessment of security
measures which have been developed more generally for related wireless networks
such as sensor networks and vehicular ad hoc networks, including a taxonomy of
all considered approaches.Comment: Survey, 22 Pages, 21 Figure
Modeling IoT-aware Business Processes - A State of the Art Report
This research report presents an analysis of the state of the art of modeling
Internet of Things (IoT)-aware business processes. IOT links the physical world
to the digital world. Traditionally, we would find information about events and
processes in the physical world in the digital world entered by humans and
humans using this information to control the physical world. In the IoT
paradigm, the physical world is equipped with sensors and actuators to create a
direct link with the digital world. Business processes are used to coordinate a
complex environment including multiple actors for a common goal, typically in
the context of administrative work. In the past few years, we have seen
research efforts on the possibilities to model IoT- aware business processes,
extending process coordination to real world entities directly. This set of
research efforts is relatively small when compared to the overall research
effort into the IoT and much of the work is still in the early research stage.
To create a basis for a bridge between IoT and BPM, the goal of this report is
to collect and analyze the state of the art of existing frameworks for modeling
IoT-aware business processes.Comment: 42 page
Monitoring and Fault Location Sensor Network for Underground Distribution Lines
One of the fundamental tasks of electric distribution utilities is guaranteeing a continuous
supply of electricity to their customers. The primary distribution network is a critical part of these
facilities because a fault in it could affect thousands of customers. However, the complexity of
this network has been increased with the irruption of distributed generation, typical in a Smart
Grid and which has significantly complicated some of the analyses, making it impossible to apply
traditional techniques. This problem is intensified in underground lines where access is limited. As a
possible solution, this paper proposes to make a deployment of a distributed sensor network along
the power lines. This network proposes taking advantage of its distributed character to support new
approaches of these analyses. In this sense, this paper describes the aquiculture of the proposed
network (adapted to the power grid) based on nodes that use power line communication and energy
harvesting techniques. In this sense, it also describes the implementation of a real prototype that
has been used in some experiments to validate this technological adaptation. Additionally, beyond
a simple use for monitoring, this paper also proposes the use of this approach to solve two typical
distribution system operator problems, such as: fault location and failure forecasting in power cables.Ministerio de Economía y Competitividad, Government of Spain project Sistema Inteligente Inalámbrico para Análisis y Monitorización de Líneas de Tensión Subterráneas en Smart Grids (SIIAM) TEC2013-40767-RMinisterio de Educación, Cultura y Deporte, Government of Spain, for the funding of the scholarship Formación de Profesorado Universitario 2016 (FPU 2016
A Survey of Positioning Systems Using Visible LED Lights
© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.As Global Positioning System (GPS) cannot provide satisfying performance in indoor environments, indoor positioning technology, which utilizes indoor wireless signals instead of GPS signals, has grown rapidly in recent years. Meanwhile, visible light communication (VLC) using light devices such as light emitting diodes (LEDs) has been deemed to be a promising candidate in the heterogeneous wireless networks that may collaborate with radio frequencies (RF) wireless networks. In particular, light-fidelity has a great potential for deployment in future indoor environments because of its high throughput and security advantages. This paper provides a comprehensive study of a novel positioning technology based on visible white LED lights, which has attracted much attention from both academia and industry. The essential characteristics and principles of this system are deeply discussed, and relevant positioning algorithms and designs are classified and elaborated. This paper undertakes a thorough investigation into current LED-based indoor positioning systems and compares their performance through many aspects, such as test environment, accuracy, and cost. It presents indoor hybrid positioning systems among VLC and other systems (e.g., inertial sensors and RF systems). We also review and classify outdoor VLC positioning applications for the first time. Finally, this paper surveys major advances as well as open issues, challenges, and future research directions in VLC positioning systems.Peer reviewe
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