272 research outputs found

    A Reinforcement Learning Agent for Minutiae Extraction from Fingerprints

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    In this paper we show that reinforcement learning can be used for minutiae detection in fingerprint matching. Minutiae are characteristic features of fingerprints that determine their uniqueness. Classical approaches use a series of image processing steps for this task, but lack robustness because they are highly sensitive to noise and image quality. We propose a more robust approach, in which an autonomous agent walks around in the fingerprint and learns how to follow ridges in the fingerprint and how to recognize minutiae. The agent is situated in the environment, the fingerprint, and uses reinforcement learning to obtain an optimal policy. Multi-layer perceptrons are used for overcoming the difficulties of the large state space. By choosing the right reward structure and learning environment, the agent is able to learn the task. One of the main difficulties is that the goal states are not easily specified, for they are part of the learning task as well. That is, the recognition of minutiae has to be learned in addition to learning how to walk over the ridges in the fingerprint. Results of successful first experiments are presented

    Gaze Behavior, Believability, Likability and the iCat

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    A First Step toward the Automatic Understanding of Social Touch for Naturalistic Human–Robot Interaction

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    Social robots should be able to automatically understand and respond to human touch. The meaning of touch does not only depend on the form of touch but also on the context in which the touch takes place. To gain more insight into the factors that are relevant to interpret the meaning of touch within a social context we elicited touch behaviors by letting participants interact with a robot pet companion in the context of different affective scenarios. In a contextualized lab setting, participants (n = 31) acted as if they were coming home in different emotional states (i.e., stressed, depressed, relaxed, and excited) without being given specific instructions on the kinds of behaviors that they should display. Based on video footage of the interactions and interviews we explored the use of touch behaviors, the expressed social messages, and the expected robot pet responses. Results show that emotional state influenced the social messages that were communicated to the robot pet as well as the expected responses. Furthermore, it was found that multimodal cues were used to communicate with the robot pet, that is, participants often talked to the robot pet while touching it and making eye contact. Additionally, the findings of this study indicate that the categorization of touch behaviors into discrete touch gesture categories based on dictionary definitions is not a suitable approach to capture the complex nature of touch behaviors in less controlled settings. These findings can inform the design of a behavioral model for robot pet companions and future directions to interpret touch behaviors in less controlled settings are discussed

    Use of wireless sensor networks for distributed event detection in disaster management applications

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    Recently, wireless sensor networks (WSNs) have become mature enough to go beyond being simple fine-grained continuous monitoring platforms and have become one of the enabling technologies for early-warning disaster systems. Event detection functionality of WSNs can be of great help and importance for (near) real-time detection of, for example, meteorological natural hazards and wild and residential fires. From the data-mining perspective, many real world events exhibit specific patterns, which can be detected by applying machine learning (ML) techniques. In this paper, we introduce ML techniques for distributed event detection in WSNs and evaluate their performance and applicability for early detection of disasters, specifically residential fires. To this end, we present a distributed event detection approach incorporating a novel reputation-based voting and the decision tree and evaluate its performance in terms of detection accuracy and time complexity

    Bacteria Hunt: A multimodal, multiparadigm BCI game

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    Brain-Computer Interfaces (BCIs) allow users to control applications by brain activity. Among their possible applications for non-disabled people, games are promising candidates. BCIs can enrich game play by the mental and affective state information they contain. During the eNTERFACE’09 workshop we developed the Bacteria Hunt game which can be played by keyboard and BCI, using SSVEP and relative alpha power. We conducted experiments in order to investigate what difference positive vs. negative neurofeedback would have on subjects’ relaxation states and how well the different BCI paradigms can be used together. We observed no significant difference in mean alpha band power, thus relaxation, and in user experience between the games applying positive and negative feedback. We also found that alpha power before SSVEP stimulation was significantly higher than alpha power during SSVEP stimulation indicating that there is some interference between the two BCI paradigms

    Chloride-induced corrosion of steel in concrete -- insights from bimodal neutron and X-ray microtomography combined with ex-situ microscopy

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    The steel-concrete interface (SCI) is known to play a major role in corrosion of steel in concrete, but a fundamental understanding is still lacking. One reason is that concrete's opacity complicates the study of internal processes. Here, we report on the application of bimodal X-ray and neutron microtomography as in-situ imaging techniques to elucidate the mechanism of steel corrosion in concrete. The study demonstrates that the segmentation of the specimen components of relevance - steel, cementitious matrix, aggregates, voids, corrosion products - obtained through bimodal X-ray and neutron imaging is more reliable than that based on the results of each of the two techniques separately. Further, we suggest the combination of tomographic in-situ imaging with ex-situ SEM analysis of targeted sections, selected on the basis of the segmented tomograms. These in-situ and ex-situ characterization techniques were applied to study localized corrosion in a very early stage, on reinforced concrete cores retrieved from a concrete bridge. A number of interesting observations were made. First, the acquired images revealed the formation of several corrosion sites close to each other. Second, the morphology of the corrosion pits was relatively shallow. Finally, only about half of the total 31 corrosion initiation spots were in close proximity to interfacial macroscopic air voids, and above 90 percent of the more than 160 interfacial macroscopic air voids were free from corrosion. The findings have implications for the mechanistic understanding of corrosion of steel in concrete and suggest that multimodal in-situ imaging is a valuable technique for further related studies

    The role of Comprehension in Requirements and Implications for Use Case Descriptions

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    Within requirements engineering it is generally accepted that in writing specifications (or indeed any requirements phase document), one attempts to produce an artefact which will be simple to comprehend for the user. That is, whether the document is intended for customers to validate requirements, or engineers to understand what the design must deliver, comprehension is an important goal for the author. Indeed, advice on producing ‘readable’ or ‘understandable’ documents is often included in courses on requirements engineering. However, few researchers, particularly within the software engineering domain, have attempted either to define or to understand the nature of comprehension and it’s implications for guidance on the production of quality requirements. Therefore, this paper examines thoroughly the nature of textual comprehension, drawing heavily from research in discourse process, and suggests some implications for requirements (and other) software documentation. In essence, we find that the guidance on writing requirements, often prevalent within software engineering, may be based upon assumptions which are an oversimplification of the nature of comprehension. Hence, the paper examines guidelines which have been proposed, in this case for use case descriptions, and the extent to which they agree with discourse process theory; before suggesting refinements to the guidelines which attempt to utilise lessons learned from our richer understanding of the underlying discourse process theory. For example, we suggest subtly different sets of writing guidelines for the different tasks of requirements, specification and design

    Water vapour diffusion through historically relevant glutin-based wood adhesives with sorption measurements and neutron radiography

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    In this work, the sorption and moisture diffusion behaviour of historically relevant glutin-based adhesives (i.e. bone glue, hide glue, fish glue) is characterized. The adhesive's sorption isotherms were assessed on thin film samples revealing fundamental differences between the glutin-based adhesives and the synthetic reference adhesive (polyurethane). Furthermore, the water vapour diffusion parallel to the fibre was examined by means of neutron imaging on bonded two-layer samples of Norway spruce wood. In contrast to previous studies using neutron imaging, a new evaluation approach is presented, which allows for nonzero initial moisture conditions and takes into account and compensates for the geometry changes in the sample caused by swelling and shrinkage, thus allowing for a characterization of the diffusion behaviour within the glue line. The diffusion coefficients determined with neutron imaging were interpreted in terms of a theoretical model which takes into account the glue line microstructure. Although the diffusion coefficients were on average larger values for the glutin-based adhesives compared to the reference polyurethane adhesive, the significant variation observed in the sorption measurement is not reflected. This can partially be ascribed to excessive penetration of the adhesives into the wood substrate in fibre direction, which impedes a continuous adhesive layer. Furthermore, deformation and densification of the wood structure was assessed in the vicinity of the adhesive joint. This effect can be ascribed to the surface roughness, which results in very high local stresses leading to buckling and deformation of the tracheids. This situation is similar to that found for adhesive joints in or close to the fibre direction such as finger or butt joints

    Quality of life and pain in premenopausal women with major depressive disorder: The POWER Study

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    BACKGROUND: Whereas it is established that organic pain may induce depression, it is unclear whether pain is more common in healthy subjects with depression. We assessed the prevalence of pain in premenopausal women with major depression (MDD). Subjects were 21- to 45-year-old premenopausal women with MDD (N = 70; age: 35.4 +/- 6.6; mean +/- SD) and healthy matched controls (N = 36; age 35.4 +/- 6.4) participating in a study of bone turnover, the P.O.W.E.R. (Premenopausal, Osteopenia/Osteoporosis, Women, Alendronate, Depression) Study. METHODS: Patients received a clinical assessment by a pain specialist, which included the administration of two standardized forms for pain, the Brief Pain Inventory – Short Form, and the Initial Pain Assessment Tool, and two scales of everyday stressors, the Hassles and Uplifts Scales. In addition, a quality-of-life instrument, the SF-36, was used. The diagnosis of MDD was established by a semi-structured interview, according to the DSM-IV criteria. Substance P (SP) and calcitonin-gene-related-peptide (CGRP), neuropeptides which are known mediators of pain, were measured every hour for 24 h in a subgroup of patients (N = 17) and controls (N = 14). RESULTS: Approximately one-half of the women with depression reported pain of mild intensity. Pain intensity was significantly correlated with the severity of depression (r(2 )= 0.076; P = 0.04) and tended to be correlated with the severity of anxiety, (r(2 )= 0.065; P = 0.07), and the number of depressive episodes (r(2 )= 0.072; P = 0.09). Women with MDD complained of fatigue, insomnia, and memory problems and experienced everyday negative stressors more frequently than controls. Quality of life was decreased in women with depression, as indicated by lower scores in the emotional and social well-being domains of the SF-36. SP (P < 0.0003) and CGRP (P < 0.0001) were higher in depressed subjects. CONCLUSION: Women with depression experienced pain more frequently than controls, had a lower quality of life, and complained more of daily stressors. Assessment of pain may be important in the clinical evaluation of women with MDD. SP and CGRP may be useful biological markers in women with MDD

    Controversial aspects of imaging in child abuse: a second roundtable discussion from the ESPR child abuse taskforce

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    This second roundtable discussion was convened at the 56th European Society of Paediatric Radiology (ESPR) 2022 Annual Meeting in Marseille, France, to discuss controversial aspects of imaging in child abuse. The following topics were discussed: Fracture dating—the published literature is broadly similar with respect to the identification of the radiographic stages of bony healing. The non-expert/general radiologist is encouraged to use broad descriptors of fracture healing (acute, healing or old) within their reports, rather than attempting to date fractures. The more experienced/expert radiologist, who may provide a timeframe/range to assist the courts, should be aware that any published timeframes are not absolute and that recent research indicates that the rate of healing may differ according to the bone affected and the age of the patient. Whole spine imaging in suspected abusive head trauma—this is recommended to enable a complete assessment of the neuraxis when abusive head trauma is suspected or diagnosed, particularly in the presence of intracranial and cervical subdural haemorrhage and cervical ligamentous injury. Cranial imaging in suspected physical abuse—both computed tomography (CT) and magnetic resonance imaging (MRI) remain complimentary depending on the clinical context in which they are used with CT remaining first-line in the assessment of children with (suspected abusive) head trauma prior to an early MRI. MRI is superior in its assessment of parenchymal injury and may be employed as first-line in age appropriate asymptomatic siblings of a child with suspected physical abuse
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