6,340 research outputs found
Platforms and Protocols for the Internet of Things
Building a general architecture for the Internet of Things (IoT) is a very complex task, exacerbated by the extremely large variety of devices, link layer technologies, and services that may be involved in such a system. In this paper, we identify the main blocks of a generic IoT architecture, describing their features and requirements, and analyze the most common approaches proposed in the literature for each block. In particular, we compare three of the most important communication technologies for IoT purposes, i.e., REST, MQTT, and AMQP, and we also analyze three IoT platforms: openHAB, Sentilo, and Parse. The analysis will prove the importance of adopting an integrated approach that jointly addresses several issues and is able to flexibly accommodate the requirements of the various elements of the system. We also discuss a use case which illustrates the design challenges and the choices to make when selecting which protocols and technologies to use
Long-Range Communications in Unlicensed Bands: the Rising Stars in the IoT and Smart City Scenarios
Connectivity is probably the most basic building block of the Internet of
Things (IoT) paradigm. Up to know, the two main approaches to provide data
access to the \emph{things} have been based either on multi-hop mesh networks
using short-range communication technologies in the unlicensed spectrum, or on
long-range, legacy cellular technologies, mainly 2G/GSM, operating in the
corresponding licensed frequency bands. Recently, these reference models have
been challenged by a new type of wireless connectivity, characterized by
low-rate, long-range transmission technologies in the unlicensed sub-GHz
frequency bands, used to realize access networks with star topology which are
referred to a \emph{Low-Power Wide Area Networks} (LPWANs). In this paper, we
introduce this new approach to provide connectivity in the IoT scenario,
discussing its advantages over the established paradigms in terms of
efficiency, effectiveness, and architectural design, in particular for the
typical Smart Cities applications
Architecture for Mobile Heterogeneous Multi Domain Networks
Multi domain networks can be used in several scenarios including military, enterprize networks, emergency networks and many other cases. In such networks, each domain might be under its own administration. Therefore, the cooperation among domains is conditioned by individual domain policies regarding sharing information, such as network topology, connectivity, mobility, security, various service availability and so on. We propose a new architecture for Heterogeneous Multi Domain (HMD) networks, in which one the operations are subject to specific domain policies. We propose a hierarchical architecture, with an infrastructure of gateways at highest-control level that enables policy based interconnection, mobility and other services among domains. Gateways are responsible for translation among different communication protocols, including routing, signalling, and security. Besides the architecture, we discuss in more details the mobility and adaptive capacity of services in HMD. We discuss the HMD scalability and other advantages compared to existing architectural and mobility solutions. Furthermore, we analyze the dynamic availability at the control level of the hierarchy
The MobyDick Project: A Mobile Heterogeneous All-IP Architecture
Proceedings of Advanced Technologies, Applications and Market Strategies for 3G (ATAMS 2001). Cracow, Poland: 17-20 June, 2001.This paper presents the current stage of an IP-based architecture for heterogeneous environments, covering UMTS-like W-CDMA wireless access technology, wireless and wired LANs, that is being developed under the aegis of the IST Moby Dick project. This architecture treats all transmission capabilities as basic physical and data-link layers, and attempts to replace all higher-level tasks by IP-based strategies.
The proposed architecture incorporates aspects of mobile-IPv6, fast handover, AAA-control, and Quality of Service. The architecture allows for an optimised control on the radio link layer resources. The Moby dick architecture is currently under refinement for implementation on field trials. The services planned for trials are data transfer and voice-over-IP.Publicad
Coloured Petrinet for Modelling and Validation of Dynamic Transmission Range Adjustment Protocol for Ad Hoc Network
The IEEE 802.11 standard defines two operational modes for WLANs: infrastructure based and infrastructureless or ad hoc. A wireless ad hoc network comprises of nodes that communicate with each other without the help of any centralized control. Ad hoc implies that the network does not rely on a pre-existing infrastructure but rather each node participates in routing by forwarding data for other nodes. The decentralized nature improves the scalability of wireless ad hoc network as compared to wireless managed networks.
Each node acts as either a host or router. A node that is within the transmission range of any other node can establish a link with the later and becomes its immediate neighbour.
However, the nodes in the ad hoc networks are constrained with limited resources and computation capability. So it may not be possible for a node to serve more number of neighbours at some instant of time. This enforces a node to remain connected or disconnected with few of its existing neighbours supporting the dynamic restructuring of the network. The presence of dynamic and adaptive routing protocol enables ad hoc networks to be formed quickly.
The Dynamic Transmission Range Adjustment Protocol (DTRAP) provides a mechanism for adjusting transmission range of the ad hoc nodes. They maintain a threshold number of registered neighbours based on their available resources. The node protects its neighbourhood relationship during data communication by controlling its transmission range.
It registers or de-registers a communicating node as its neighbour by dynamically varying the transmission range. However a node has a maximum limit on its transmission range.
If the distance between the node and its neighbour is less than the transmission range and;
1)if the number of neighbours of a node falls short of threshold value, the node dynamically increases its transmission range in steps until it is ensured of an optimal number of neighbours
2)if the number of neighbours of a node exceeds the threshold value, the node dynamically decreases its transmission range in steps until it is ensured of an optimal number of neighbours.
Coloured Petri nets (CP-nets) is the modelling language tool used for systems having communication, synchronisation and resource sharing as significant aspects. It provides
a framework for the design, specication, validation, and verication of systems. It describes the states in which the system may be in and the transition between these states.
The CPN combines Petri nets and programming languages. Petri nets amalgamate the use of graphical notation and the semantical foundation for modelling in systems. The functional programming language standard ML provides the primitives for the definition of data types and manipulation of data values. Besides providing the strength of a graphical modelling language, CP-nets are theoretically well-founded and versatile enough to be used in practice for systems of the size and complexity of industrial projects
Towards a Layered Architectural View for Security Analysis in SCADA Systems
Supervisory Control and Data Acquisition (SCADA) systems support and control
the operation of many critical infrastructures that our society depend on, such
as power grids. Since SCADA systems become a target for cyber attacks and the
potential impact of a successful attack could lead to disastrous consequences
in the physical world, ensuring the security of these systems is of vital
importance. A fundamental prerequisite to securing a SCADA system is a clear
understanding and a consistent view of its architecture. However, because of
the complexity and scale of SCADA systems, this is challenging to acquire. In
this paper, we propose a layered architectural view for SCADA systems, which
aims at building a common ground among stakeholders and supporting the
implementation of security analysis. In order to manage the complexity and
scale, we define four interrelated architectural layers, and uses the concept
of viewpoints to focus on a subset of the system. We indicate the applicability
of our approach in the context of SCADA system security analysis.Comment: 7 pages, 4 figure
Separation of Circulating Tokens
Self-stabilizing distributed control is often modeled by token abstractions.
A system with a single token may implement mutual exclusion; a system with
multiple tokens may ensure that immediate neighbors do not simultaneously enjoy
a privilege. For a cyber-physical system, tokens may represent physical objects
whose movement is controlled. The problem studied in this paper is to ensure
that a synchronous system with m circulating tokens has at least d distance
between tokens. This problem is first considered in a ring where d is given
whilst m and the ring size n are unknown. The protocol solving this problem can
be uniform, with all processes running the same program, or it can be
non-uniform, with some processes acting only as token relays. The protocol for
this first problem is simple, and can be expressed with Petri net formalism. A
second problem is to maximize d when m is given, and n is unknown. For the
second problem, the paper presents a non-uniform protocol with a single
corrective process.Comment: 22 pages, 7 figures, epsf and pstricks in LaTe
Robotic Wireless Sensor Networks
In this chapter, we present a literature survey of an emerging, cutting-edge,
and multi-disciplinary field of research at the intersection of Robotics and
Wireless Sensor Networks (WSN) which we refer to as Robotic Wireless Sensor
Networks (RWSN). We define a RWSN as an autonomous networked multi-robot system
that aims to achieve certain sensing goals while meeting and maintaining
certain communication performance requirements, through cooperative control,
learning and adaptation. While both of the component areas, i.e., Robotics and
WSN, are very well-known and well-explored, there exist a whole set of new
opportunities and research directions at the intersection of these two fields
which are relatively or even completely unexplored. One such example would be
the use of a set of robotic routers to set up a temporary communication path
between a sender and a receiver that uses the controlled mobility to the
advantage of packet routing. We find that there exist only a limited number of
articles to be directly categorized as RWSN related works whereas there exist a
range of articles in the robotics and the WSN literature that are also relevant
to this new field of research. To connect the dots, we first identify the core
problems and research trends related to RWSN such as connectivity,
localization, routing, and robust flow of information. Next, we classify the
existing research on RWSN as well as the relevant state-of-the-arts from
robotics and WSN community according to the problems and trends identified in
the first step. Lastly, we analyze what is missing in the existing literature,
and identify topics that require more research attention in the future
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