| 1. |
- Conte, Gianpaolo, 1974-, et al.
(författare)
-
An Integrated UAV Navigation System Based on Aerial Image Matching
- 2008
-
Ingår i: IEEE Aerospace Conference 2008,2008. - : IEEE. - 9781424414871 - 9781424414888 ; , s. 3142-3151
-
Konferensbidrag (refereegranskat)abstract
- The aim of this paper is to explore the possibility of using geo-referenced satellite or aerial images to augment an Unmanned Aerial Vehicle (UAV) navigation system in case of GPS failure. A vision based navigation system which combines inertial sensors, visual odometer and registration of a UAV on-board video to a given geo-referenced aerial image has been developed and tested on real flight-test data. The experimental results show that it is possible to extract useful position information from aerial imagery even when the UAV is flying at low altitude. It is shown that such information can be used in an automated way to compensate the drift of the UAV state estimation which occurs when only inertial sensors and visual odometer are used.
|
|
| 2. |
- Conte, Gianpaolo, 1974-, et al.
(författare)
-
High Accuracy Ground Target Geo-Location Using Autonomous Micro Aerial Vehicle Platforms
- 2008
-
Ingår i: Proceedings of the AIAA Guidance, Navigation, and Control Conference (GNC). - : AIAA. - 9781563479458
-
Konferensbidrag (refereegranskat)abstract
- This paper presents a method for high accuracy ground target localization using a Micro Aerial Vehicle (MAV) equipped with a video camera sensor. The proposed method is based on a satellite or aerial image registration technique. The target geo-location is calculated by registering the ground target image taken from an on-board video camera with a geo- referenced satellite image. This method does not require accurate knowledge of the aircraft position and attitude, therefore it is especially suitable for MAV platforms which do not have the capability to carry accurate sensors due to their limited payload weight and power resources. The paper presents results of a ground target geo-location experiment based on an image registration technique. The platform used is a MAV prototype which won the 3rd US-European Micro Aerial Vehicle Competition (MAV07). In the experiment a ground object was localized with an accuracy of 2.3 meters from a ight altitude of 70 meters.
|
|
| 3. |
- Doherty, Patrick, 1957-, et al.
(författare)
-
A UAV search and rescue scenario with human body detection and geolocalization
- 2007
-
Ingår i: Proceedings of the 20th Australian Joint Conference on Artificial Intelligence (AI). - : Springer Berlin/Heidelberg. - 9783540769262
-
Konferensbidrag (refereegranskat)abstract
- The use of Unmanned Aerial Vehicles (UAVs) which can operate autonomously in dynamic and complex operational environments is becoming increasingly more common. The UAVTech Lab, is pursuing a long term research endeavour related to the development of future aviation systems which try and push the envelope in terms of using and integrating high-level deliberative or AI functionality with traditional reactive and control components in autonomous UAV systems. In order to carry on such research, one requires challenging mission scenarios which force such integration and development. In this paper, one of these challenging emergency services mission scenarios is presented. It involves search and rescue for injured civilians by UAVs. In leg I of the mission, UAVs scan designated areas and try to identify injured civilians. In leg II of the mission, an attempt is made to deliver medical and other supplies to identified victims. We show how far we have come in implementing and executing such a challenging mission in realistic urban scenarios.
|
|
| 4. |
- Doherty, Patrick, 1957-, et al.
(författare)
-
Approximate Databases : A support tool for approximate reasoning
- 2006
-
Ingår i: Journal of applied non-classical logics. - : Éditions Hermès-Lavoisier. - 1166-3081 .- 1958-5780. ; 16:1-2, s. 87-118
-
Tidskriftsartikel (refereegranskat)abstract
- This paper describes an experimental platform for approximate knowledge databases called the Approximate Knowledge Database (AKDB), based on a semantics inspired by rough sets. The implementation is based upon the use of a standard SQL database to store logical facts, augmented with several query interface layers implemented in JAVA through which extensional, intensional and local closed world nonmonotonic queries in the form of crisp or approximate logical formulas can be evaluated tractably. A graphical database design user interface is also provided which simplifies the design of databases, the entering of data and the construction of queries. The theory and semantics for AKDBs is presented in addition to application examples and details concerning the database implementation.
|
|
| 5. |
- Doherty, Patrick, 1957-, et al.
(författare)
-
Dynamics of approximate information fusion
- 2007
-
Ingår i: Proceedings of the International Conference on Rough Sets and Emerging Intelligent Systems Paradigms (RSEISP). - Heidelberg, Germany : Springer Berlin/Heidelberg. - 9783540734505 ; , s. 668-677
-
Konferensbidrag (refereegranskat)abstract
- The multi-agent system paradigm has proven to be a useful means of abstraction when considering distributed systems with interacting components. It is often the case that each component may be viewed as an intelligent agent with specific and often limited perceptual capabilities. It is also the case that these agent components may be used as information sources and such sources may be aggregated to provide global information about particular states, situations or activities in the embedding environment. This paper investigates a framework for information fusion based on the use of generalizations of rough set theory and the use of dynamic logic as a basis for aggregating similarity relations among objects where the similarity relations represent individual agents perceptual capabilities or limitations. As an added benefit, it is shown how this idea may also be integrated into description logics.
|
|
| 6. |
- Doherty, Patrick, 1957-
(författare)
-
Knowledge representation and unmanned aerial vehicles
- 2005
-
Ingår i: Proceedings of the IEEE/WIC/ACM International Conference on Intelligent Agent Technology (IAT). - : IEEE Computer Society. - 0769524168 ; , s. 9-16
-
Konferensbidrag (refereegranskat)abstract
- Knowledge representation technologies play a fundamental role in any autonomous system that includes deliberative capability and that internalizes models of its internal and external environments. Integrating both high- and low-end autonomous functionality seamlessly in autonomous architectures is currently one of the major open problems in robotics research. UAVs offer especially difficult challenges in comparison with ground robotic systems due to the often tight time constraints and safety considerations that must be taken into account. This article provides an overview of some of the knowledge representation technologies and deliberative capabilities developed for a fully deployed autonomous unmanned aerial vehicle system to meet some of these challenges.
|
|
| 7. |
- Doherty, Patrick, 1957-, et al.
(författare)
-
Knowledge Representation Techniques. : a rough set approach
- 2006
-
Bok (övrigt vetenskapligt/konstnärligt)abstract
- The basis for the material in this book centers around a long term research project with autonomous unmanned aerial vehicle systems. One of the main research topics in the project is knowledge representation and reasoning. The focus of the research has been on the development of tractable combinations of approximate and nonmonotonic reasoning systems. The techniques developed are based on intuitions from rough set theory. Efforts have been made to take theory into practice by instantiating research results in the context of traditional relational database or deductive database systems. This book contains a cohesive, self-contained collection of many of the theoretical and applied research results that have been achieved in this project and for the most part pertain to nonmonotonic and approximate reasoning systems developed for an experimental unmanned aerial vehicle system used in the project. This book should be of interest to the theoretician and applied researcher alike and to autonomous system developers and software agent and intelligent system developers.
|
|
| 8. |
- Doherty, Patrick, 1957-, et al.
(författare)
-
Reasoning with Qualitative Preferences and Cardinalities Using Generalized Circumscription
- 2008
-
Ingår i: Proceedings of the 11th International Conference on Principles of Knowledge Representation and Reasoning (KR). - : AAAI Press. - 9781577353843 ; , s. 560-570
-
Konferensbidrag (refereegranskat)abstract
- The topic of preference modeling has recently attracted the interest of a number of sub-disciplines in artificial intelligence such as the nonmonotonic reasoning and action and change communities. The approach in these communities focuses on qualitative preferences and preference models which provide more natural representations from a~commonsense perspective. In this paper, we show how generalized circumscription can be used as a highly expressive framework for qualitative preference modeling. Generalized circumscription proposed by Lifschitz allows for predicates (and thus formulas) to be minimized relative to arbitrary pre-orders (reflexive and transitive). Although it has received little attention, we show how it may be used to model and reason about elaborate qualitative preference relations. One of the perceived weaknesses with any type of circumscription is the 2nd-order nature of the representation. The paper shows how a large variety of preference theories represented using generalized circumscription can in fact be reduced to logically equivalent first-order theories in a constructive way. Finally, we also show how preference relations represented using general circumscription can be extended with cardinality constraints and when these extensions can also be reduced to logically equivalent first-order theories.
|
|
| 9. |
- Doherty, Patrick, 1957-, et al.
(författare)
-
Similarity, approximations and vagueness
- 2005
-
Ingår i: Proceedings of the 10th International Conference on Rough Sets, Fuzzy Sets, Data Mining, and Granular Computing (RSFDGrC). - Berlin, Heidelberg : Springer. - 3540286535 ; , s. 541-550
-
Konferensbidrag (refereegranskat)abstract
- The relation of similarity is essential in understanding and developing frameworks for reasoning with vague and approximate concepts. There is a wide spectrum of choice as to what properties we associate with similarity and such choices determine the nature of vague and approximate concepts defined in terms of these relations. Additionally, robotic systems naturally have to deal with vague and approximate concepts due to the limitations in reasoning and sensor capabilities. Halpern [1] introduces the use of subjective and objective states in a modal logic formalizing vagueness and distinctions in transitivity when an agent reasons in the context of sensory and other limitations. He also relates these ideas to a solution to the Sorities and other paradoxes. In this paper, we generalize and apply the idea of similarity and tolerance spaces [2,3,4,5], a means of constructing approximate and vague concepts from such spaces and an explicit way to distinguish between an agent’s objective and subjective states. We also show how some of the intuitions from Halpern can be used with similarity spaces to formalize the above-mentioned Sorities and other paradoxes.
|
|
| 10. |
- Doherty, Patrick, 1957-, et al.
(författare)
-
Temporal Action Logics
- 2009
-
Ingår i: Handbook of Knowledge Representation. - : Elsevier. - 9780444522115 ; , s. 709-757
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The study of frameworks and formalisms for reasoning about action and change [67, 58, 61, 65, 70, 3, 57] has been central to the knowledge representation field almost from the inception of Artificial Intelligence as a general field of research [52, 56]. The phrase “Temporal Action Logics” represents a class of logics for reasoning about action and change that evolved from Sandewall’s book on Features and Fluents [61] and owes much to this ambitious project. There are essentially three major parts to Sandewall’s work. He first developed a narrative-based logical framework for specifying agent behavior in terms of action scenarios. The logical framework is state-based and uses explicit time structures. He then developed a formal framework for assessing the correctness (soundness and completeness) of logics for reasoning about action and change relative to a set of well-defined intended conclusions, where reasoning problems were classified according to their ontological or epistemological characteristics. Finally, he proposed a number of logics defined semantically in terms of definitions of preferential entailment1 and assessed their correctness using his assessment framework.
|
|
