10 research outputs found
Artificial intelligence methods for security and cyber security systems
This research is in threat analysis and countermeasures employing Artificial Intelligence (AI) methods within the civilian domain, where safety and mission-critical aspects are essential. AI has challenges of repeatable determinism and decision explanation. This research proposed methods for dense and convolutional networks that provided repeatable determinism. In dense networks, the proposed alternative method had an equal performance with more structured learnt weights. The proposed method also had earlier learning and higher accuracy in the Convolutional networks. When demonstrated in colour image classification, the accuracy improved in the first epoch to 67%, from 29% in the existing scheme. Examined in transferred learning with the Fast Sign Gradient Method (FSGM) as an analytical method to control distortion of dissimilarity, a finding was that the proposed method had more significant retention of the learnt model, with 31% accuracy instead of 9%. The research also proposed a threat analysis method with set-mappings and first principle analytical steps applied to a Symbolic AI method using an algebraic expert system with virtualized neurons. The neural expert system method demonstrated the infilling of parameters by calculating beamwidths with variations in the uncertainty of the antenna type. When combined with a proposed formula extraction method, it provides the potential for machine learning of new rules as a Neuro-Symbolic AI method. The proposed method uses extra weights allocated to neuron input value ranges as activation strengths. The method simplifies the learnt representation reducing model depth, thus with less significant dropout potential. Finally, an image classification method for emitter identification is proposed with a synthetic dataset generation method and shows the accurate identification between fourteen radar emission modes with high ambiguity between them (and achieved 99.8% accuracy). That method would be a mechanism to recognize non-threat civil radars aimed at threat alert when deviations from those civilian emitters are detected
Autonomous agents for multi-function radar resource management
The multifunction radar, aided by advances in electronically steered phased array technology, is capable
of supporting numerous, differing and potentially conflicting tasks. However, the full potential of the
radar system is only realised through its ability to automatically manage and configure the finite resource
it has available. This thesis details the novel application of agent systems to this multifunction radar
resource management problem. Agent systems are computational societies where the synergy of local
interactions between agents produces emergent, global desirable behaviour.
In this thesis the measures and models which can be used to allocate radar resource is explored; this
choice of objective function is crucial as it determines which attribute is allocated resource and consequently
constitutes a description of the problem to be solved. A variety of task specific and information
theoretic measures are derived and compared. It is shown that by utilising as wide a variety of measures
and models as possible the radar’s multifunction capability is enhanced.
An agent based radar resource manager is developed using the JADE Framework which is used
to apply the sequential first price auction and continuous double auctions to the multifunction radar
resource management problem. The application of the sequential first price auction leads to the development
of the Sequential First Price Auction Resource Management algorithm from which numerous
novel conclusions on radar resource management algorithm design are drawn. The application of the
continuous double auction leads to the development of the Continuous Double Auction Parameter Selection
(CDAPS) algorithm. The CDAPS algorithm improves the current state of the art by producing
an improved allocation with low computational burden. The algorithm is shown to give worthwhile
improvements in task performance over a conventional rule based approach for the tracking and surveillance
functions as well as exhibiting graceful degradation and adaptation to a dynamic environment
Naval Postgraduate School Catalog 2016
Approved for public release; distribution is unlimited
Naval Postgraduate School Catalog 2015
Approved for public release; distribution is unlimited
Scanning policy optimization for LPRF maritime radars
In this work, we study the detection performance of a multi-channel radar system in the presence of sea-clutter. The transmitter adopts a broad beam (whose width is a design parameter), while the receiver forms multiple contiguous narrow beams covering the same region. The key performance measures are derived and the interplay among the width of the transmit beam, the scan duration, the signal-to-noise ratio, and the signal-to-clutter ratio are elicited. Numerical results are provided to show the possible tradeoffs