| 1. |
- Ingvarsson, Jonas, 1966-, et al.
(författare)
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Digitalisering och poetisk form
- 2012. - 1
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Ingår i: Litteraturens nätverk. - Lund : Studentlitteratur AB. - 9789144076751 ; , s. 97-111
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 2. |
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| 3. |
- Billing, Erik, 1981-
(författare)
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Cognition Rehearsed : Recognition and Reproduction of Demonstrated Behavior
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The work presented in this dissertation investigates techniques for robot Learning from Demonstration (LFD). LFD is a well established approach where the robot is to learn from a set of demonstrations. The dissertation focuses on LFD where a human teacher demonstrates a behavior by controlling the robot via teleoperation. After demonstration, the robot should be able to reproduce the demonstrated behavior under varying conditions. In particular, the dissertation investigates techniques where previous behavioral knowledge is used as bias for generalization of demonstrations. The primary contribution of this work is the development and evaluation of a semi-reactive approach to LFD called Predictive Sequence Learning (PSL). PSL has many interesting properties applied as a learning algorithm for robots. Few assumptions are introduced and little task-specific configuration is needed. PSL can be seen as a variable-order Markov model that progressively builds up the ability to predict or simulate future sensory-motor events, given a history of past events. The knowledge base generated during learning can be used to control the robot, such that the demonstrated behavior is reproduced. The same knowledge base can also be used to recognize an on-going behavior by comparing predicted sensor states with actual observations. Behavior recognition is an important part of LFD, both as a way to communicate with the human user and as a technique that allows the robot to use previous knowledge as parts of new, more complex, controllers. In addition to the work on PSL, this dissertation provides a broad discussion on representation, recognition, and learning of robot behavior. LFD-related concepts such as demonstration, repetition, goal, and behavior are defined and analyzed, with focus on how bias is introduced by the use of behavior primitives. This analysis results in a formalism where LFD is described as transitions between information spaces. Assuming that the behavior recognition problem is partly solved, ways to deal with remaining ambiguities in the interpretation of a demonstration are proposed. The evaluation of PSL shows that the algorithm can efficiently learn and reproduce simple behaviors. The algorithm is able to generalize to previously unseen situations while maintaining the reactive properties of the system. As the complexity of the demonstrated behavior increases, knowledge of one part of the behavior sometimes interferes with knowledge of another parts. As a result, different situations with similar sensory-motor interactions are sometimes confused and the robot fails to reproduce the behavior. One way to handle these issues is to introduce a context layer that can support PSL by providing bias for predictions. Parts of the knowledge base that appear to fit the present context are highlighted, while other parts are inhibited. Which context should be active is continually re-evaluated using behavior recognition. This technique takes inspiration from several neurocomputational models that describe parts of the human brain as a hierarchical prediction system. With behavior recognition active, continually selecting the most suitable context for the present situation, the problem of knowledge interference is significantly reduced and the robot can successfully reproduce also more complex behaviors.
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| 4. |
- Billing, Erik, 1981-
(författare)
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Cognition reversed : Robot learning from demonstration
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The work presented in this thesis investigates techniques for learning from demonstration (LFD). LFD is a well established approach to robot learning, where a teacher demonstrates a behavior to a robot pupil. This thesis focuses on LFD where a human teacher demonstrates a behavior by controlling the robot via teleoperation. The robot should after demonstration be able to execute the demonstrated behavior under varying conditions. Several views on representation, recognition and learning of robot behavior are presented and discussed from a cognitive and computational perspective. LFD-related concepts such as behavior, goal, demonstration, and repetition are defined and analyzed, with focus on how bias is introduced by the use of behavior primitives. This analysis results in a formalism where LFD is described as transitions between information spaces. Assuming that the behavior recognition problem is partly solved, ways to deal with remaining ambiguities in the interpretation of a demonstration are proposed. A total of five algorithms for behavior recognition are proposed and evaluated, including the dynamic temporal difference algorithm Predictive Sequence Learning (PSL). PSL is model-free in the sense that it makes few assumptions of what is to be learned. One strength of PSL is that it can be used for both robot control and recognition of behavior. While many methods for behavior recognition are concerned with identifying invariants within a set of demonstrations, PSL takes a different approach by using purely predictive measures. This may be one way to reduce the need for bias in learning. PSL is, in its current form, subjected to combinatorial explosion as the input space grows, which makes it necessary to introduce some higher level coordination for learning of complex behaviors in real-world robots. The thesis also gives a broad introduction to computational models of the human brain, where a tight coupling between perception and action plays a central role. With the focus on generation of bias, typical features of existing attempts to explain humans' and other animals' ability to learn are presented and analyzed, from both a neurological and an information theoretic perspective. Based on this analysis, four requirements for implementing general learning ability in robots are proposed. These requirements provide guidance to how a coordinating structure around PSL and similar algorithms should be implemented in a model-free way.
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| 5. |
- Billing, Erik, et al.
(författare)
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Composer : A prototype multilingual model composition tool
- 2013
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Ingår i: MODPROD2013. - Umeå : Umeå universitet.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Composer - A prototype multilingual model composition toolErik Billing and Martin ServinNovember 10, 2012Facing the task to design, simulate or optimize a complex system itis common to find models and data for the system expressed in differentformats, implemented in different simulation software tools. When a newmodel is developed, a target platform is chosen and existing componentsimplemented with different tools have to be converted. This results inunnecessary work duplication and lead times. The Modelica languageinitiative [2] partially solves this by allowing developers to move modelsbetween different tools following the Modelica standard. Another possi-bility is to exchange models using the Functional Mockup Interface (FMI)standard that allows computer models to be used as components in othersimulations, possibly implemented using other programming languages[1]. With the Modelica and FMI standards entering development, there isneed for an easy-to-use tool that supports design, editing and simulationof such multilingual systems, as well as for retracting system informationfor formulating and solving optimization problems.A prototype solution for a graphical block diagram tool for design, edit-ing, simulation and optimization of multilingual systems has been createdand evaluated for a specific system. The tool is named Composer [3].The block diagram representation should be generic, independent ofmodel implementations, have a standardized format and yet support effi-cient handling of complex data. It is natural to look for solutions amongmodern web technologies, specifically HTML5. The format for represent-ing two dimensional vector graphics in HTML5 is Scalable Vector Graphics(SVG). We combine the SVG format with the FMI standard. In a firststage, we take the XML-based model description of FMI as a form for de-scribing the interface for each component, in a language independent way.Simulation parameters can also be expressed on this form, and integratedas metadata into the SVG image. The prototype, using SVG in conjunction with FMI, is implementedin JavaScript and allow creation and modification of block diagrams directly in the web browser. Generated SVG images are sent to the serverwhere they are translated to program code, allowing the simulation ofthe dynamical system to be executed using selected implementations. Analternative mode is to generate optimization problem from the systemdefinition and model parameters. The simulation/optimization result is returned to the web browser where it is plotted or processed using otherstandard libraries.The fiber production process at SCA Packaging Obbola [4] is used asan example system and modeled using Composer. The system consists oftwo fiber production lines that produce fiber going to a storage tank [5].The paper machine is taking fiber from the tank as needed for production.A lot of power is required during fiber production and the purpose of themodel was to investigate weather electricity costs could be reduced byrescheduling fiber production over the day, in accordance with the electricity spot price. Components are implemented for dynamical simulationusing OpenModelica and for discrete event using Python. The Python implementation supports constraint propagation between components andoptimization over specified variables. Each component is interfaced as aFunctional Mock-up Unit (FMU), allowing components to be connectedand properties specified in language independent way. From the SVGcontaining the high-level system information, both Modelica and Pythoncode is generated and executed on the web server, potentially hosted ina high performance data center. More implementations could be addedwithout modifying the SVG system description.We have shown that it is possible to separate system descriptions onthe block diagram level from implementations and interface between thetwo levels using FMI. In a continuation of this project, we aim to integratethe FMI standard also for co-simulation, such that components implemented in different languages could be used together. One open questionis to what extent FMUs of the same component, but implemented withdifferent tools, will have the same model description. For the SVG-basedsystem description to be useful, the FMI model description must remainthe same, or at least contain a large overlap, for a single component implemented in different languages. This will be further investigated in futurework.References[1] Modelica Association. Functional mock-up interface, http://www.fmi-standard.org, November 2012.[2] Modelica Association. Modelica and the modelica association, http://www.modelica.org, November 2012.[3] Erik Billing and Martin Servin. Composer, http://imuit.cs.umu.se/composer, November 2012. [4] SCA Packaging. Sca packaging obbola, http://www.scapackaging.com, November 2012.[5] Patrik Törmänen and Hussein Jaffal. Reducing electricity cost - case study. Technical report, UMIT Research Lab, Umeå University, 2011.2
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| 6. |
- Billing, Erik, 1981-, et al.
(författare)
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Formalising learning from demonstration
- 2008
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The paper describes and formalizes the concepts and assumptions involved in Learning from Demonstration (LFD), a common learning technique used in robotics. Inspired by the work on planning and actuation by LaValle, common LFD-related concepts like goal, generalization, and repetition are here defined, analyzed, and put into context. Robot behaviors are described in terms of trajectories through information spaces and learning is formulated as the mappings between some of these spaces. Finally, behavior primitives are introduced as one example of useful bias in the learning process, dividing the learning process into the three stages of behavior segmentation, behavior recognition, and behavior coordination.
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| 7. |
- Billing, Erik, 1981-
(författare)
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Representing behavior : Distributed theories in a context of robotics
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A growing body of research within the field of intelligent robotics argues for a view of intelligence drastically different from classical artificial intelligence and cognitive science. The holistic and embodied ideas expressed by this research sees emergence as the springing source for intelligence. Similar perspectives, where numerous interactions within the system lead to emergent properties and cognitive abilities beyond that of the individual parts, can be found within many scientific fields. With the goal of understanding how behavior may be represented in robots, the present review tries to grasp what this notion of emergence really means and compare it with a selection of theories developed for analysis of human cognition. These theories reveal a view of intelligence where common notions of objects, goals and reasoning have to be rethought. A view where behavior, as well as the agent as such, is in the eye of the observer rather than given. Structures in the environment is achieved by interaction rather than recognized. In such a view, the fundamental question is how emergent systems appear and develop, and how they may be controlled.
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| 8. |
- Billing, Erik, 1981-, et al.
(författare)
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Simultaneous control and recognition of demonstrated behavior
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A method for Learning from Demonstration (LFD) is presented and evaluated on a simulated Robosoft Kompai robot. The presented algorithm, called Predictive Sequence Learning (PSL), builds fuzzy rules describing temporal relations between sensory-motor events recorded while a human operator is tele-operating the robot. The generated rule base can be used to control the robot and to predict expected sensor events in response to executed actions. The rule base can be trained under different contexts, represented as fuzzy sets. In the present work, contexts are used to represent different behaviors. Several behaviors can in this way be stored in the same rule base and partly share information. The context that best matches present circumstances can be identified using the predictive model and the robot can in this way automatically identify the most suitable behavior for precent circumstances. The performance of PSL as a method for LFD is evaluated with, and without, contextual information. The results indicate that PSL without contexts can learn and reproduce simple behaviors. The system also successfully identifies the most suitable context in almost all test cases. The robot's ability to reproduce more complex behaviors, with partly overlapping and conflicting information, significantly increases with the use of contexts. The results support a further development of PSL as a component of a dynamic hierarchical system performing control and predictions on several levels of abstraction.
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| 9. |
- Eriksson, Irene, 1965-
(författare)
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Urinary tract infection : a serious health problem in old women
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Urinary tract infection (UTI) is a common bacterial infection in women of all ages but the incidence and prevalence increase with age. Despite the high incidence of UTI, little is known about its impact on morale or subjective wellbeing and daily life in old women. UTI in older people can be a complex problem in terms of approach to diagnosis, treatment and prevention because in these patients it frequently presents with a range of atypical symptoms such as delirium, gastrointestinal signs and falls. Even if UTI has been shown to be associated with delirium it has frequently been questioned whether UTI can cause delirium or if it is only accidentally detected when people with delirium are assessed. The main purpose of this thesis was to describe the prevalence of UTI, to identify factors associated with UTI among very old women and to illuminate the impact of a UTI on old women’s health and wellbeing. This thesis is based on two main studies, the GErontological Regional DAtabase (GERDA) a cross-sectional, population-based study carried out in the northern parts of Sweden and Finland during 2005-2007 and a qualitative interview study in western Sweden 2008-2009. Data were collected from structured interviews and assessments made during home visits, from medical records, care givers and relatives. UTI was diagnosed if the person had a documented symptomatic UTI, with either short- or long-term ongoing treatment with antibiotics, or symptoms and laboratory tests judged to indicate the presence of UTI by the responsible physician or the assessor. One hundred and seventeen out of 395 women (29.6%) were diagnosed as having suffered from at least one UTI during the preceding year and 233 of these 395 (60%) had had at least one diagnosed UTI during the preceding 5 years. These old women with UTI were more dependent in their activities of daily living, and had poorer cognition and nutrition. In these women, UTI during the preceding year was associated with vertebral fractures, urinary incontinence, inflammatory rheumatic disease and multi-infarct dementia. Eighty-seven of 504 women (17.3%), were diagnosed as having a UTI with or without ongoing treatment when they were assessed, and almost half (44.8%) were diagnosed as delirious or having had episodes of delirium during the past month. In all, 137 of the 504 women (27.2%) were delirious or had had episodes of delirium during the past month and 39 (28.5%) of them were diagnosed as having a UTI. Delirium was associated with Alzheimer’s disease, multi-infarct dementia, depression, heart failure and UTI. Forty-six out of 319 women (14.4%) were diagnosed as having had a UTI with or without ongoing treatment and these had a significantly lower score on the Philadelphia Geriatric Center Morale Scale (PGCMS), (10.4 vs 11.9, p=0.003) than those without UTI, indicating a significant impact on morale or subjective wellbeing among very old women. The medical diagnoses significantly and independently associated with low morale were depression, UTI and constipation. The experience of suffering from repeated UTI was described in interviews conducted with 20 old women. The interviews were analysed using qualitative content analysis. The participants described living with repeated UTI as being in a state of manageable suffering and being dependent on alleviation. Being in a state of manageable suffering was described in terms of experiencing physical and psychological inconveniences, struggling to deal with the illness and being restricted regarding daily life. Being dependent on alleviation was illustrated in terms of having access to relief but also experiencing receiving inadequate care. In conclusion, UTI is very common among old and very old women and is a serious health problem. UTI seems to be associated with delirium and to have a significant impact on the morale or subjective wellbeing of old women and those affected suffer both physically and psychologically and their social life is limited. UTI was also associated with vertebral fractures, urinary incontinence, inflammatory rheumatic disease and multi-infarct dementia which might raise the suspicion that UTI can have serious medical effects on health in old women.
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| 10. |
- Torstensson, Niklas
(författare)
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Judging the Immigrant : Accents and Attitudes
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Spoken language as a means of communication contains huge amounts of information apart from the linguistic message that is conveyed. It is often the first channel of interaction between people and based on the speaker’s manner of talk, we create a mental image of the speaker as a person, of the speaker’s background, origin and personal qualities. Through five case studies, this dissertation investigates how immigrants to Sweden are judged based on their foreign accents (Cases 1—3) and how the use of an interpreter in court can affect the legal process and the judging of the immigrant (Cases 4—5). Case 1 investigated Swedish students’ attitudes towards immigration and immigrants through a survey-based study and revealed that Swedish students hold predominantly positive attitudes towards immigrations and immigrants. Case 2, using accent imitation, asked if Swedish speakers have a cognitive prototype for British English accented Swedish and found that this was the case. This demonstrated that Swedes have models of accented Swedish accents. Case 3 asked Swedish students to rate their impressions of speakers of nine foreign accented Swedish voices on 18 six-point semantic differential scales. They also rated their impressions of each voice for five social factors. The results suggest that the listeners evaluated the voices based on perceived social desirability, or perceived cultural distance between the listener and the voice’s country of origin. Juxtaposing these findings with those of Case 1 suggests that even among a group who are positive to immigrants and immigration some groups of immigrants are more welcome than others. Case 4 examined discourse disfluencies in a bilingual court hearing and a Swedish-Polish bilingual court hearing in detail. The case showed that most of the dialogue-related difficulties have other sources than the interpreter, even if the interpreter at first glance often appeared to be part of the problem rather than part of the solution. Case 5 examined the interpreter’s role in courtroom dialogue situations through interviews with a court interpreter and a lay judge. The study found that the picture of the interpreter’s role differs between the various actors in the court setting. This, in combination with a lack of knowledge about cultural differences in dialogue strategies, creates complications, can have an impact on the perception of the witness and, ultimately, affect the legal rights of the accused. Furthermore, as the interpreter most frequently speaks foreign accented Swedish, the perception and evaluation of their foreign accented Swedish can further place some immigrant groups at a double legal disadvantage when being judged.
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