Abstract: Page 1
Universiteit van Amsteram
A Color Based Rangefinder for
an Omnidirectional Camera
June 26, 2009
A Color Based Rangefinder for an Omnidirectional
Bachelor Thesis (Afstudeerscriptie)
Quang Nguyen, 5619793
(born Februari 3rd, 1988 in Assen, the Netherlands)
under the supervision of Arnoud Visser
submitted in partial fulfillment of the requirements for the degree of
Bsc Kunstmatige Intelligentie
at the Universiteit van Amsterdam.
This paper proposes a method to use the omnidirectional camera as a rangefinder
by using color detection. The omnicam rangefinder has been tested in USAR-
Sim for its accuracy and for its practical use to build maps of the environment.
The results of the test shows that an omnidirectional camera can be used to
accurately estimate distances to obstacles and to create maps of unknown envi-
Abstract: This paper focuses on the method and implementation of a map generator for the USARSim environment, which is capable of generating indoor environments. The generator adapts to a difficulty measure, which signifies how difficult the generated map should be, when mapped by a robot. Both the method of the procedural generation process as well as the knowledge on the difficulty measure are explained, followed by the implementation of the generator. Multiple maps with various difficulties are generated and mapping runs are simulated by experienced robot operators. Then the difficulty is assessed by these operators and compared to the difficulty level of the maps. The rules of the generator turn out to be able to influence the difficulty of the maps, but due to the complexities of ’difficulty’ it is difficult to do this consistently.
Abstract: An experimental automated dialogue system that plays the role of a crisis hotline dispatcher is currently developed. Besides controlling the communication flow, this system is able to retrieve information about crisis situations from user's input. It offers a natural user interaction by the ability to perceive and respond to human emotions. The system has an emotion recognizer that is able to recognize the emotional loading from user's linguistic content. The recognizer uses a database that contains selected keywords on a 2D "arousal" and "valence" scale. The output of the system provides not only the information about the user's emotional state but also an indication of the urgency of his/her information regarding to crisis. The dialogue system is able to start a user friendly dialogue, taking care of the content, context and emotional loading of user's utterances.
Abstract: This paper introduces an information theoretic approach to verification of causal models in modular Bayesian fusion systems. We assume distributed fusion systems which are gradually extended by adding new modules, each having a limited domain knowledge captured in local Bayesian networks. However, since dierent modules originate from different, independent design processes important dependencies between the variables in different modules might not correctly be captured in the distributed fusion system. This could have a significant impact on the fusion quality. The introduced
method supports discovery of significant dependencies which are ignored in the distributed fusion system.
Abstract: Omnidirectional vision is currently an important sensor in robotic research. The catadioptric omnidirectional camera with a hyperbolic convex mirror is a common omnidirectional vision system in the robotics research field as it has many advantages over other vision systems. This paper describes the development and validation of such a system for the RoboCup Rescue League simulator USARSim.
After an introduction of the mathematical properties of a real catadioptric omnidirectional camera we give a general overview of the simulation method. We then compare different 3D mirror meshes with respect to quality and system performance. Simulation data also is compared to real omnidirectional vision data obtained on an 4-Legged League soccer field. Comparison is based on using color histogram landmark detection and robot self-localization based on an Extended Kalman filter.
Abstract: Even though adaptive (trainable) spam filters are a common example of systems that make (semi-)autonomous decisions on behalf of the user, trust in these filters has been underexplored. This paper reports a study of usage of spam filters in the daily workplace and user behaviour in training these filters (N=43). User observation, interview and survey techniques were applied to investigate attitudes towards two types of filters: a user-adaptive (trainable) and a rule-based filter. While many of our participants invested extensive effort in training their filters, training did not influence filter trust. Instead, the findings indicate that users' filter awareness and understanding seriously impacts attitudes and behaviour. Specific examples of difficulties related to awareness of filter activity and adaptivity are described showing concerns relevant to all adaptive and (semi-)autonomous systems that rely on explicit user feedback.
Abstract: Describe the way the simulation model will be broken down into usable parts
for the simulator.
This is an important design document that tries to abstract from a specific
implementation. So methods and algorithms are described in pseudo code. It
does contain details on the actual implementation in a separate chapter.
This document is written as a reference document. So note that properties
and methods are added as they are found to be necessary. Not all properties
have been described directly in their accompanying text, because their
necessity becomes clear later in the document. For clarity these properties
and methods are still shown in the paragraph on the object itself.
Abstract: We introduce Distributed perception networks (DPNs), a distributed architecture for efficient and reliable fusion of large quantities of heterogeneous and noisy information. DPNs consist of agents, processing nodes with limited fusion capabilities, which cooperate and can autonomously form arbitrarily large distributed classifiers. DPNs are based on causal models, which often facilitate analysis, design and maintenance of complex information fusion systems. This is possible because
observations obtained from different information sources often result from causal processes which in turn can be modeled with relatively simple, yet mathematically rigorous and compact probabilistic causal models. Such models, in turn, facilitate
decentralized world modeling and information fusion.
Abstract: This paper presents the map evaluation methodology developed for the Virtual Robots Rescue competition held as part of RoboCup. The procedure aims to evaluate the quality of maps produced by multi-robot systems with respect to a number of factors, including usability, exploration, annotation and other aspects relevant to robots and first responders. In addition to the design choices, we illustrate practical examples of maps and scores coming from the latest RoboCup contest, outlining strengths and weaknesses of our modus operandi. We also show how a benchmarking methodology developed for a simulation testbed effortlessly and faithfully transfers to maps built by a real robot. A number of conclusions may be derived from the experience reported in this paper and a thorough discussion is offered.
Abstract: The RoboCup is an initiative to promote the development of robotics in a social relevant way. The competition consists of several leagues and it would be benecial if developments in one league could be reused in other leagues. This paper describes the development of a simulation model for a humanoid robot inside USARSim, which could be the basis of synergy between the Rescue Simulation, Soccer Simulation and @Home League. USARSim is an existing 3D simulator based on the Unreal Engine, which provides facilities for good quality rendering, physics simulation, networking, a highly versatile scripting language and a powerful visual editor. This simulator is now extended with the dynamics of a walking robot and validated for the humanoid robot Nao. On this basis many other robotic applications as benchmarked in the RoboCup initiative become possible.
Abstract: User demands for usability in mobile context due to the small size of personal data assistants (PDAs) challenge traditional input design. An on-screen keyboard that offers an easier and faster method of entering text with a pen on PDAs, has been developed. We have developed a method for adapting its predictive ability according to user's personal word usage, input context and syntax rules. Frequently used characters are presented to the users in different key sizes and color contrasts according to their relative probabilities to aid visual searching. For this purpose, an experiment has been conducted on which and how to use (user's) data source for faster prediction. In this experiment, we compared four dictionaries recorded from the British National Corpus, personal documents, chat logs and personal e-mails. The experimental results show ways to improve the performance of the word prediction and the language coverage of the word completion.
Abstract: Conducting empirical research involves a balancing act between scientific rigor and real-life pragmatics. The Delft Co-operation on Intelligent Systems (D-CIS) laboratory researches systems-of-systems consisting of the human and artificial systems involved in collaborative decision-making under chaotic circumstances. An important objective is the usefulness of our results in our major application domain: crisis management. The D-CIS lab was involved in setting up a crisis management exercise experiment and the according measurements regarding an improvement in internal communication at Gemeente (Municipality) Borsele. In this paper, the empirical research regarding this experiment, the methodology and its results are briefly outlined. The main lessons learned concern the interrelationship between the scenario, experiment and measurements, the problem of acquiring usable data and the challenges of conducting grounded research.
Abstract: Conducting empirical research involves a balancing act between scientific rigor and real-life pragmatics. DECIS Lab researches systems-of-systems, consisting of humans and artificial systems involved in collaborative decision making under chaotic circumstances. An important objective is the usefulness of our results to our major application domain: crisis management. DECIS Lab was involved to set up a crisis management exercise experiment and according measurements regarding an improvement in internal communication at Gemeente (Municipality) Borsele. In this paper the empirical research regarding this experiment, the methodology and its results are briefly outlined. Our main lessons learned concern the interrelationship between scenario, experiment and measurements; the problem of acquiring usable data; and the challenges of conducting grounded research.
Abstract: Emotion influences the choice of facial expression. In a dialogue the emotional state is co-determined by the events that happen during a dialogue. To enable rich, human like expressiveness of a dialogue agent, the facial displays should show a correct expression of the state of the agent in the dialogue. This paper reports about our study in building knowledge on how to appropriately express emotions in face to face communication. We have analyzed the appearance of facial expressions and corresponding dialogue-text (in balloons) of characters of selected cartoon illustrations. From the facial expressions and dialogue-text, we have extracted independently the emotional state and the communicative function. We also collected emotion words from the dialogue-text. The emotional states (label) and the emotion words are represented along two dimensions �arousal� and �valence�. Here, the relationship between facial expressions and text were explored. The final goal of this research is to develop emotional-display rules for a text-based dialogue agent.
Abstract: In this position paper a number of hypotheses are outlined concerning the effect of three measurable human factors, namely subjective stress, arousal and mood, on human decision making performance; taking into account the amount of risk involved in the decision. The proposed domain of application involves critical situations: situations in which time-limits, uncertainty and possibly dire consequences provide an ideal context to apply the results. A tangible objective is to provide the basis for a demonstrator which can measure subjective stress, arousal and mood on the job, provide runtime feedback and positively influence the human decision making process.
Abstract: In this position paper a number of hypotheses are posited concerning the effect of measurable human factors, such as subjective stress, arousal and mood, on the performance of human decision making; taking into account the amount of risk involved in the decision. The proposed domain of application is crisis management: a situation in which time-limits, uncertainty and possibly dire consequences provide an ideal context to assess the validity of our hypotheses. Experimentation involves both people in management functions and non-management functions. The final objective is to provide the basis for a demonstrator which can measure mood, arousal and subjective stress on the job, provide runtime feedback and ergo positively influence human decision making processes.
Abstract: This paper introduces the MultiAgent Decision Process software toolbox, an open source C++ library for decision-theoretic planning under uncertainty in multiagent systems. It provides support for several multiagent models, such as POSGs, Dec-POMDPs and MMDPs. The toolbox aims to reduce development time for planning algorithms and to provide a benchmarking platform by providing a number of commonly used problem descriptions. It features a parser for a text-based ﬁle format for discrete Dec-POMDPs, shared functionality for planning algorithms, as well as the implementation of several Dec-POMDP planners. We describe design goals and architecture of the toolbox, and provide an overview of its functionality, illustrated by some usage examples. Finally we report on current and future work.
Abstract: This paper describes a model to replicate the dynamics of a walking robot inside USARSim. USARSim is an existing 3D simulator based on the Unreal Engine, which provides facilities for good quality rendering, physics simulation, networking, a highly versatile scripting language and a powerful visual editor. To model the dynamics of a walking robot the balance of the robot in relation with the contact points of the body with the environment has to be calculated. To guarantee a fast frame rate several approximations in this calculation have to be tried, and the performance (both in dynamics and computational effort) is evaluated in a number of experiments. This extension is made and validated for the humanoid robot Nao. On this basis many other applications become possible. A validated simulation allows
us to develop and to experiment with typical robotic tasks before they are tested on a real robot.
Abstract: The term vigilance is used frequently in a wide variety of research areas. The British neurologist Sir Henry Head introduced the term to refer to a state of high consciousness. Nowadays, ‘vigilance’ is used in neurophysiological research, but also in the experimental psychological field. Related terms, such as arousal, sustained attention, and tonic alertness are often used jointly with or instead of the term vigilance. It may seem that all these designations can be interchanged freely, but this is not the case. Many investigators differentiate these terms and the distinctions made are not always subtle. The terminological confusion of vigilance involves on the one hand its definition (i.e. clarification of the theoretical construct) with reference to different processes, and on the other hand different measuring procedures. The original definition of vigilance: “… a high state of physiological efficiency” is rather physiological in nature, but the “efficiency” part points to behavior. Head’s clarification that a vigilant state differs from a pure condition of raised excitability appears to be of major importance. The combination of physiological activity and efficient behavior is of great relevance and underlines the difference between vigilance and more basic energetic conditions.
The topic of this paper is the exploration of procedures for measuring vigilance. EEG-measures are very popular and are described first. More specifically, the spectral content of the EEG is investigated. Second, behavioral measures are presented. These concern performance on vigilance tasks. Finally, subjective questionnaires are explored.