303 research outputs found
Routing and privacy protection in human associated delay tolerant networks
This thesis proposes Human Associated Delay Tolerant Networks, where data communications among mobile nodes are determined by human social behaviours. Three models are proposed to handle the social attributes effect on data forwarding, the time impact on nodes’ movement and the privacy protection issue when social attributes are introduced
Air Force Institute of Technology Research Report 2007
This report summarizes the research activities of the Air Force Institute of Technologyâs Graduate School of Engineering and Management. It describes research interests and faculty expertise; lists student theses/dissertations; identifies research sponsors and contributions; and outlines the procedures for contacting the school. Included in the report are: faculty publications, conference presentations, consultations, and funded research projects. Research was conducted in the areas of Aeronautical and Astronautical Engineering, Electrical Engineering and Electro-Optics, Computer Engineering and Computer Science, Systems and Engineering Management, Operational Sciences, Mathematics, Statistics and Engineering Physics
Biologically inspired, self organizing communication networks.
PhDThe problem of energy-efficient, reliable, accurate and self-organized target tracking in
Wireless Sensor Networks (WSNs) is considered for sensor nodes with limited physical
resources and abrupt manoeuvring mobile targets. A biologically inspired, adaptive
multi-sensor scheme is proposed for collaborative Single Target Tracking (STT) and
Multi-Target Tracking (MTT). Behavioural data obtained while tracking the targets
including the targetsâ previous locations is recorded as metadata to compute the target
sampling interval, target importance and local monitoring interval so that tracking
continuity and energy-efficiency are improved. The subsequent sensor groups that track
the targets are selected proactively according to the information associated with the
predicted target location probability such that the overall tracking performance is
optimized or nearly-optimized. One sensor node from each of the selected groups is
elected as a main node for management operations so that energy efficiency and load
balancing are improved. A decision algorithm is proposed to allow the âconflictâ nodes
that are located in the sensing areas of more than one target at the same time to decide
their preferred target according to the target importance and the distance to the target. A
tracking recovery mechanism is developed to provide the tracking reliability in the
event of target loss.
The problem of task mapping and scheduling in WSNs is also considered. A
Biological Independent Task Allocation (BITA) algorithm and a Biological Task
Mapping and Scheduling (BTMS) algorithm are developed to execute an application
using a group of sensor nodes. BITA, BTMS and the functional specialization of the
sensor groups in target tracking are all inspired from biological behaviours of
differentiation in zygote formation.
Simulation results show that compared with other well-known schemes, the
proposed tracking, task mapping and scheduling schemes can provide a significant
improvement in energy-efficiency and computational time, whilst maintaining
acceptable accuracy and seamless tracking, even with abrupt manoeuvring targets.Queen Mary university of London full Scholarshi
Ranking Edges by their Impact on the Spectral Complexity of Information Diffusion over Networks
Despite the numerous ways now available to quantify which parts or subsystems
of a network are most important, there remains a lack of centrality measures
that are related to the complexity of information flows and are derived
directly from entropy measures. Here, we introduce a ranking of edges based on
how each edge's removal would change a system's von Neumann entropy (VNE),
which is a spectral-entropy measure that has been adapted from quantum
information theory to quantify the complexity of information dynamics over
networks. We show that a direct calculation of such rankings is computationally
inefficient (or unfeasible) for large networks: e.g.\ the scaling is
per edge for networks with nodes. To overcome this
limitation, we employ spectral perturbation theory to estimate VNE
perturbations and derive an approximate edge-ranking algorithm that is accurate
and fast to compute, scaling as per edge. Focusing on a form
of VNE that is associated with a transport operator , where is a graph Laplacian matrix and is a diffusion timescale
parameter, we apply this approach to diverse applications including a network
encoding polarized voting patterns of the 117th U.S. Senate, a multimodal
transportation system including roads and metro lines in London, and a
multiplex brain network encoding correlated human brain activity. Our
experiments highlight situations where the edges that are considered to be most
important for information diffusion complexity can dramatically change as one
considers short, intermediate and long timescales for diffusion.Comment: 24 pages, 7 figure
Exploiting the power of multiplicity: a holistic survey of network-layer multipath
The Internet is inherently a multipath network: For an underlying network with only a single path, connecting various nodes would have been debilitatingly fragile. Unfortunately, traditional Internet technologies have been designed around the restrictive assumption of a single working path between a source and a destination. The lack of native multipath support constrains network performance even as the underlying network is richly connected and has redundant multiple paths. Computer networks can exploit the power of multiplicity, through which a diverse collection of paths is resource pooled as a single resource, to unlock the inherent redundancy of the Internet. This opens up a new vista of opportunities, promising increased throughput (through concurrent usage of multiple paths) and increased reliability and fault tolerance (through the use of multiple paths in backup/redundant arrangements). There are many emerging trends in networking that signify that the Internet's future will be multipath, including the use of multipath technology in data center computing; the ready availability of multiple heterogeneous radio interfaces in wireless (such as Wi-Fi and cellular) in wireless devices; ubiquity of mobile devices that are multihomed with heterogeneous access networks; and the development and standardization of multipath transport protocols such as multipath TCP. The aim of this paper is to provide a comprehensive survey of the literature on network-layer multipath solutions. We will present a detailed investigation of two important design issues, namely, the control plane problem of how to compute and select the routes and the data plane problem of how to split the flow on the computed paths. The main contribution of this paper is a systematic articulation of the main design issues in network-layer multipath routing along with a broad-ranging survey of the vast literature on network-layer multipathing. We also highlight open issues and identify directions for future work
Methods and Measures for Analyzing Complex Street Networks and Urban Form
Complex systems have been widely studied by social and natural scientists in
terms of their dynamics and their structure. Scholars of cities and urban
planning have incorporated complexity theories from qualitative and
quantitative perspectives. From a structural standpoint, the urban form may be
characterized by the morphological complexity of its circulation networks -
particularly their density, resilience, centrality, and connectedness. This
dissertation unpacks theories of nonlinearity and complex systems, then
develops a framework for assessing the complexity of urban form and street
networks. It introduces a new tool, OSMnx, to collect street network and other
urban form data for anywhere in the world, then analyze and visualize them.
Finally, it presents a large empirical study of 27,000 street networks,
examining their metric and topological complexity relevant to urban design,
transportation research, and the human experience of the built environment.Comment: PhD thesis (2017), City and Regional Planning, UC Berkele
Air Force Institute of Technology Research Report 2012
This report summarizes the research activities of the Air Force Institute of Technologyâs Graduate School of Engineering and Management. It describes research interests and faculty expertise; lists student theses/dissertations; identifies research sponsors and contributions; and outlines the procedures for contacting the school. Included in the report are: faculty publications, conference presentations, consultations, and funded research projects. Research was conducted in the areas of Aeronautical and Astronautical Engineering, Electrical Engineering and Electro-Optics, Computer Engineering and Computer Science, Systems and Engineering Management, Operational Sciences, Mathematics, Statistics and Engineering Physics
The structure and dynamics of multilayer networks
In the past years, network theory has successfully characterized the
interaction among the constituents of a variety of complex systems, ranging
from biological to technological, and social systems. However, up until
recently, attention was almost exclusively given to networks in which all
components were treated on equivalent footing, while neglecting all the extra
information about the temporal- or context-related properties of the
interactions under study. Only in the last years, taking advantage of the
enhanced resolution in real data sets, network scientists have directed their
interest to the multiplex character of real-world systems, and explicitly
considered the time-varying and multilayer nature of networks. We offer here a
comprehensive review on both structural and dynamical organization of graphs
made of diverse relationships (layers) between its constituents, and cover
several relevant issues, from a full redefinition of the basic structural
measures, to understanding how the multilayer nature of the network affects
processes and dynamics.Comment: In Press, Accepted Manuscript, Physics Reports 201
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