24,450 research outputs found
Memory-augmented cognitive radar for obstacle avoidance using nearest steering vector search
Abstract This study describes a cognitive radar architecture with application to real‐time obstacle avoidance in mobile robotic platforms. The concept of a world memory map is introduced as a means of providing an enhanced perception of the environment around the robotic platform. This is combined with a specially designed obstacle avoidance algorithm, Nearest Steering Vector Searching, all capable of operating in real‐time. The study analytically derives the radar signal processing algorithm, starting from range‐angle maps, so that a collision free course to a set destination point can be robustly navigated. Finally, the performance of this cognitive approach is examined through a number of proof‐of‐concept experiments using a commercial off‐the‐shelf radar mounted on a mobile ground robotic platform
Cognitive network structure: an experimental study
In this paper we present first experimental results about a small group of
people exchanging private and public messages in a virtual community. Our goal
is the study of the cognitive network that emerges during a chat seance. We
used the Derrida coefficient and the triangle structure under the working
assumption that moods and perceived mutual affinity can produce results
complementary to a full semantic analysis. The most outstanding outcome is the
difference between the network obtained considering publicly exchanged messages
and the one considering only privately exchanged messages: in the former case,
the network is very homogeneous, in the sense that each individual interacts in
the same way with all the participants, whilst in the latter the interactions
among different agents are very heterogeneous, and are based on "the enemy of
my enemy is my friend" strategy. Finally a recent characterization of the
triangular cliques has been considered in order to describe the intimate
structure of the network. Experimental results confirm recent theoretical
studies indicating that certain 3-vertex structures can be used as indicators
for the network aging and some relevant dynamical features.Comment: 15 pages, 5 figures, 3 table
Cognitive Sub-Nyquist Hardware Prototype of a Collocated MIMO Radar
We present the design and hardware implementation of a radar prototype that
demonstrates the principle of a sub-Nyquist collocated multiple-input
multiple-output (MIMO) radar. The setup allows sampling in both spatial and
spectral domains at rates much lower than dictated by the Nyquist sampling
theorem. Our prototype realizes an X-band MIMO radar that can be configured to
have a maximum of 8 transmit and 10 receive antenna elements. We use frequency
division multiplexing (FDM) to achieve the orthogonality of MIMO waveforms and
apply the Xampling framework for signal recovery. The prototype also implements
a cognitive transmission scheme where each transmit waveform is restricted to
those pre-determined subbands of the full signal bandwidth that the receiver
samples and processes. Real-time experiments show reasonable recovery
performance while operating as a 4x5 thinned random array wherein the combined
spatial and spectral sampling factor reduction is 87.5% of that of a filled
8x10 array.Comment: 5 pages, Compressed Sensing Theory and its Applications to Radar,
Sonar and Remote Sensing (CoSeRa) 201
The Waggle Dance as an Intended Flight: A Cognitive Perspective
The notion of the waggle dance simulating a flight towards a goal in a walking pattern has been proposed in the context of evolutionary considerations. Behavioral components, like its arousing effect on the social community, the attention of hive mates induced by this behavior, the direction of the waggle run relative to the sun azimuth or to gravity, as well as the number of waggles per run, have been tentatively related to peculiar behavioral patterns in both solitary and social insect species and are thought to reflect phylogenetic pre-adaptations. Here, I ask whether these thoughts can be substantiated from a functional perspective. Communication in the waggle dance is a group phenomenon involving the dancer and the followers that perform partially overlapping movements encoding and decoding the message respectively. It is thus assumed that the dancer and follower perform close cognitive processes. This provides us with access to these cognitive processes during dance communication because the follower can be tested in its flight performance when it becomes a recruit. I argue that the dance message and the landscape experience are processed in the same navigational memory, allowing the bee to fly novel direct routes, a property understood as an indication of a cognitive map
Visual Attention to Radar Displays
A model is described which predicts the allocation of attention to the features of a radar display. It uses the growth of uncertainty and the probability of near collision to call the eye to a feature of the display. The main source of uncertainty is forgetting following a fixation, which is modelled as a two dimensional diffusion process. The model was used to predict information overload in intercept controllers, and preliminary validation obtained by recording eye movements of intercept controllers in simulated and live (practice) interception
Baseband version of the bat-inspired spectrogram correlation and transformation receiver
Echolocating bats have evolved an excellent ability to detect and discriminate targets in highly challenging environments. They have had more than 50 million years of evolution to optimise their echolocation system with respect to their surrounding environment. Behavioural experiments have shown their exceptional ability to detect and classify targets even in highly cluttered surroundings. The way bats process signals is not exactly the same as in radar and hence it can be useful to investigate the differences. The Spectrogram Correlation And Transformation receiver (SCAT) is an existing model of the bat auditory system that takes into account the physiology and underlying neural organisation in bats which emit chirped signals. In this paper, we propose a baseband receiver equivalent to the SCAT. This will allow biologically inspired signal processing to be applied to radar baseband signals. It will also enable further theoretical analysis of the key concepts, advantages and limitations of the "bat signal processing" for the purpose of target detection, localisation and resolution. The equivalence is demonstrated by comparing the output of the original SCAT to that of our proposed baseband version using both simulated and experimental target echoes. Results show that the baseband receiver provides compatible frequency interference pattern for two closely located scatterers
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