103,305 research outputs found
Distributed Connectivity Control of Mobile Networks
Control of mobile networks raises fundamental and novel problems in controlling the structure of the resulting dynamic graphs. In particular, in applications involving mobile sensor networks and multiagent systems, a great new challenge is the development of distributed motion algorithms that guarantee connectivity of the overall network. Motivated by the inherently discrete nature of graphs as combinatorial objects, we address this challenge using a key control decomposition. First, connectivity control of the network structure is performed in the discrete space of graphs and relies on local estimates of the network topology used, along with algebraic graph theory, to verify link deletions with respect to connectivity. Tie breaking, when multiple such link deletions can violate connectivity, is achieved by means of gossip algorithms and distributed market-based control. Second, motion control is performed in the continuous configuration space, where nearest-neighbor potential fields are used to maintain existing links in the network. Integration of the earlier controllers results in a distributed, multiagent, hybrid system, for which we show that the resulting motion always ensures connectivity of the network, while it reconfigures toward certain secondary objectives. Our approach can also account for communication time delays as well as collision avoidance and is illustrated in nontrivial computer simulations
Evolving Gene Regulatory Networks with Mobile DNA Mechanisms
This paper uses a recently presented abstract, tuneable Boolean regulatory
network model extended to consider aspects of mobile DNA, such as transposons.
The significant role of mobile DNA in the evolution of natural systems is
becoming increasingly clear. This paper shows how dynamically controlling
network node connectivity and function via transposon-inspired mechanisms can
be selected for in computational intelligence tasks to give improved
performance. The designs of dynamical networks intended for implementation
within the slime mould Physarum polycephalum and for the distributed control of
a smart surface are considered.Comment: 7 pages, 8 figures. arXiv admin note: substantial text overlap with
arXiv:1303.722
Efficient Information Aggregation Strategies for Distributed Control and Signal Processing
This thesis is concerned with distributed control and coordination of
networks consisting of multiple, potentially mobile, agents. This is motivated
mainly by the emergence of large scale networks characterized by the lack of
centralized access to information and time-varying connectivity. Control and
optimization algorithms deployed in such networks should be completely
distributed, relying only on local observations and information, and robust
against unexpected changes in topology such as link failures. We will describe
protocols to solve certain control and signal processing problems in this
setting. We will demonstrate that a key challenge for such systems is the
problem of computing averages in a decentralized way. Namely, we will show that
a number of distributed control and signal processing problems can be solved
straightforwardly if solutions to the averaging problem are available. The rest
of the thesis will be concerned with algorithms for the averaging problem and
its generalizations. We will (i) derive the fastest known averaging algorithms
in a variety of settings and subject to a variety of communication and storage
constraints (ii) prove a lower bound identifying a fundamental barrier for
averaging algorithms (iii) propose a new model for distributed function
computation which reflects the constraints facing many large-scale networks,
and nearly characterize the general class of functions which can be computed in
this model.Comment: Ph.D. thesis, Department of Electrical Engineering and Computer
Science, MIT, September 201
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Distributed Firewall For MANETs
Mobile Ad-hoc Networks (MANETs) are increasingly used in military tactical situations and in civil rapid-deployment networks, including emergency rescue operations and {\it ad hoc} disaster-relief networks. The flexibility of MANETs comes at a price, when compared to wired and basestation-based wireless networks: MANETs are susceptible to both insider (compromised node) and outsider attacks due to the lack of a well-defined perimeter in which to deploy firewalls, intrusion detection systems, and other mechanisms commonly used for network access and admission control. In this paper, we define a distributed firewall architecture that is designed specifically for MANETs. Our approach harnesses and extends the concept of a {\it network capability}, and is especially suited for environments where the communicating nodes have different roles and hence different communication requirements, such as in tactical networks. Our model enforces communication restrictions among MANET nodes and services, allowing hop-by-hop policy enforcement in a distributed manner. We use a ''deny-by-default'' model where compromised nodes have access only to authorized services, without the ability to disrupt or interfere with end-to-end service connectivity and nodes beyond their local communication radius. Our simulations show that our solution has minimal overhead in terms of bandwidth and latency, works well even in the presence of routing changes due to mobile nodes, and is effective in containing misbehaving nodes
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
A Fuzzy Based Distributed Algorithm for Maintaining Connected Network Topology in Mobile Ad-Hoc Networks Considering Freeway Mobility Model
Mobile Ad-Hoc Networks (MANETs) present real-time embedded system that is being used in a wide variety of applications where traditional networking infrastructure is practically infeasible. The highly dynamic character of a Mobile Ad-Hoc Network (MANET) poses significant challenges on network communications. Previous work on MANET has resulted in numerous routing protocols aiming to maintain network connectivity among the active nodes. This paper presents a fuzzy-based distributed algorithm to maintain connected MANET considering freeway mobility model. According to the algorithm, each node will control itself in a way that it can maintain its connectivity with other nodes. In this approach each node is enabled with a Global Positioning System (GPS) receiver. Through GPS each and every node is getting its position and velocity. After getting the information all the nodes in a network transmit their position and velocity information periodically. Obtaining information from all other nodes, each node will decide its own velocity to maintain connectivity. Moreover, faults to a particular node have also been considered in this algorithm. Results obtained through simulation studies show the effectiveness of the proposed algorithm
Research on Wireless Multi-hop Networks: Current State and Challenges
Wireless multi-hop networks, in various forms and under various names, are
being increasingly used in military and civilian applications. Studying
connectivity and capacity of these networks is an important problem. The
scaling behavior of connectivity and capacity when the network becomes
sufficiently large is of particular interest. In this position paper, we
briefly overview recent development and discuss research challenges and
opportunities in the area, with a focus on the network connectivity.Comment: invited position paper to International Conference on Computing,
Networking and Communications, Hawaii, USA, 201
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