oru.sePublikationer
Change search
Refine search result
1234567 151 - 200 of 815
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the 'Create feeds' function.
  • 151. Cesta, Amedeo
    et al.
    Cortellessa, Gabriella
    Rasconi, Riccardo
    Pecora, Federico
    Örebro University, School of Science and Technology.
    Scopelliti, Massimiliano
    Tiberio, Lorenza
    Monitoring elderly people with the robocare domestic environment: interaction synthesis and user evaluation2011In: Computational intelligence, ISSN 0824-7935, E-ISSN 1467-8640, Vol. 27, no 1, 60-82 p.Article in journal (Refereed)
    Abstract [en]

    This article describes aspects of a fully implemented artificial intelligence (AI) system that integrates multiple intelligent components to actively assist an elderly person at home. Specifically, we describe how constraint-based scheduling technology is used to actively monitor a pattern of activities executed by the person and how detected temporal constraint violations are used to trigger meaningful and contextualized proactive interactions. This article also presents a psychological evaluation of the system focusing on elderly people’s attitudes, in which system acceptability, perceived utility, interaction modality, and emotional response are considered.

  • 152. Cesta, Amedeo
    et al.
    Farinelli, Alessandro
    Iocchi, Luca
    Leone, Riccardo G.
    Nardi, Daniele
    Pecora, Federico
    Örebro University, Department of Technology.
    Rasconi, Riccardo
    “Robotically Rich” environments for supporting elderly people at home: the RoboCare experience2005Conference paper (Refereed)
  • 153. Cesta, Amedeo
    et al.
    Fratini, Simone
    Oddi, Angelo
    Pecora, Federico
    Örebro University, School of Science and Technology.
    APSI Case# 1: pre-planning science operations in Mars Express2008In: iSAIRAS-08, 2008Conference paper (Refereed)
  • 154. Cesta, Amedeo
    et al.
    Fratini, Simone
    Pecora, Federico
    Örebro University, Department of Technology.
    A multi-component framework for planning and scheduling integration2007Conference paper (Refereed)
  • 155. Cesta, Amedeo
    et al.
    Fratini, Simone
    Pecora, Federico
    Örebro University, School of Science and Technology.
    Planning with multiple-components in OMPS2008In: New frontiers in applied artificial intelligence / [ed] Ngoc Thanh Nguyen, Leszek Borzemski, Adam Grzech, Moonis Ali, Springer Berlin/Heidelberg, 2008, 435-445 p.Conference paper (Refereed)
  • 156. Cesta, Amedeo
    et al.
    Fratini, Simone
    Pecora, Federico
    Örebro University, School of Science and Technology.
    Unifying planning and scheduling as timelines in a component-based perspective2008In: Archives of Control Science, ISSN 1230-2384, Vol. 18, no 2, 231-271 p.Article in journal (Refereed)
    Abstract [en]

    The timeline-based approach to planning represents an effective alternative to classical planning for complex domains requiring the use of both temporal reasoning and scheduling features. This paper discusses the constraint-based approach to timeline planning and scheduling introduced in OMPS.  OMPS is a an architecture for problem solving which draws inspiration from both control theory and constraint-based reasoning, and which is based on the notion of components.The rationale behind the component-based approach shares with classical control theory a basic modeling perspective: the planning and scheduling problem is represented by identifying a set of relevant domain components which need to be controlled to obtain a desired temporal behavior for the entire system. Components are entities whose properties may vary in time and which model one or more physical (or logical) domain subsystems relevant to a given planning context. The planner/scheduler plays the role of the controller for these entities, and reasons in terms of constraints that bound their internal evolutions and the desired properties of the generated behaviors (goals). Our work complements this modeling assumption with a constraint-based computational framework.  Admissible temporal behaviors of components are specified as a set of causal constraints within a rich temporal specification, and goals are specified as temporal constraint preferences.  The OMPS software architecture presented in this paper combines both specific and generic constraint solvers in defining consistent timelines which satisfy a given set of goals.

  • 157. Cesta, Amedeo
    et al.
    Iocchi, Luca
    Leone, Giuseppe R.
    Nardi, Daniele
    Pecora, Federico
    Örebro University, Department of Technology.
    Robotic, sensory and problem-solving ingredients for the future home2009In: Intelligent environments: methods, algorithms and applications / [ed] Dorothy Monekosso, Yoshinori Kuno, Springer Berlin/Heidelberg, 2009, 67-87 p.Chapter in book (Refereed)
  • 158. Cesta, Amedeo
    et al.
    Pecora, Federico
    Örebro University, Department of Technology.
    The robocare project: intelligent systems for elder care2005Conference paper (Refereed)
  • 159. Cesta, Amedeo
    et al.
    Pecora, Federico
    Örebro University, School of Science and Technology.
    The robocare project: multi-agent systems for the care of the elderly2003In: ERCIM News, ISSN 0926-4981, E-ISSN 1564-0094, no 53Article in journal (Other academic)
  • 160. Cesta, Amedeo
    et al.
    Pecora, Federico
    Örebro University, Department of Technology.
    Rasconi, Riccardo
    A component-based framework for loosely-coupled planning and scheduling integrations2004Conference paper (Other academic)
  • 161. Cesta, Amedeo
    et al.
    Pecora, Federico
    Örebro University, Department of Technology.
    Rasconi, Riccardo
    Biasing the structure of scheduling problems through classical planners2004Conference paper (Refereed)
  • 162.
    Chadalavada, Ravi Teja
    Chalmers University of Technology.
    Human Robot Interaction for Autonomous Systems in Industrial Environments2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The upcoming new generation of autonomous vehicles for transporting materials in industrial environments will be more versatile, flexible and efficient than traditional Automatic Guided Vehicles (AGV), which simply follow pre-defined paths. However, freely navigating vehicles can appear unpredictable to human workers and thus cause stress and render joint use of the available space inefficient. This work addresses the problem of providing information regarding a service robot’s intention to humans co-populating the environment. The overall goal is to make humans feel safer and more comfortable, even when they are in close vicinity of the robot. A spatial Augmented Reality (AR) system for robot intention communication by means of projecting proxemic information onto shared floor space is developed on a robotic fork-lift by equipping it with a LED projector. This helps in visualizing internal state information and intents on the shared floors spaces. The robot’s ability to communicate its intentions is evaluated in realistic situations where test subjects meet the robotic forklift. A Likert scalebased evaluation which also includes comparisons to human-human intention communication was performed. The results show that already adding simple information, such as the trajectory and the space to be occupied by the robot in the near future, is able to effectively improve human response to the robot. This kind of synergistic human-robot interaction in a work environment is expected to increase the robot’s acceptability in the industry.

  • 163.
    Chadalavada, Ravi Teja
    et al.
    Örebro University, School of Science and Technology.
    Andreasson, Henrik
    Örebro University, School of Science and Technology.
    Krug, Robert
    Örebro University, School of Science and Technology.
    Lilienthal, Achim
    Örebro University, School of Science and Technology.
    Empirical evaluation of human trust in an expressive mobile robot2016In: Proceedings of RSS Workshop "Social Trust in Autonomous Robots 2016", 2016Conference paper (Refereed)
    Abstract [en]

    A mobile robot communicating its intentions using Spatial Augmented Reality (SAR) on the shared floor space makes humans feel safer and more comfortable around the robot. Our previous work [1] and several other works established this fact. We built upon that work by adding an adaptable information and control to the SAR module. An empirical study about how a mobile robot builds trust in humans by communicating its intentions was conducted. A novel way of evaluating that trust is presented and experimentally shown that adaption in SAR module lead to natural interaction and the new evaluation system helped us discover that the comfort levels between human-robot interactions approached those of human-human interactions.

  • 164.
    Chadalavada, Ravi Teja
    et al.
    Örebro University, School of Science and Technology.
    Andreasson, Henrik
    Örebro University, School of Science and Technology.
    Krug, Robert
    Örebro University, School of Science and Technology.
    Lilienthal, Achim
    Örebro University, School of Science and Technology.
    That’s on my Mind!: Robot to Human Intention Communication through on-board Projection on Shared Floor Space2015In: 2015 European Conference on Mobile Robots (ECMR), New York: IEEE conference proceedings , 2015Conference paper (Refereed)
    Abstract [en]

    The upcoming new generation of autonomous vehicles for transporting materials in industrial environments will be more versatile, flexible and efficient than traditional AGVs, which simply follow pre-defined paths. However, freely navigating vehicles can appear unpredictable to human workers and thus cause stress and render joint use of the available space inefficient. Here we address this issue and propose on-board intention projection on the shared floor space for communication from robot to human. We present a research prototype of a robotic fork-lift equipped with a LED projector to visualize internal state information and intents. We describe the projector system and discuss calibration issues. The robot’s ability to communicate its intentions is evaluated in realistic situations where test subjects meet the robotic forklift. The results show that already adding simple information, such as the trajectory and the space to be occupied by the robot in the near future, is able to effectively improve human response to the robot.

  • 165.
    Charusta, Krzysztof
    et al.
    Örebro University, School of Science and Technology.
    Dimitrov, Dimitar
    Örebro University, School of Science and Technology.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Iliev, Boyko
    Örebro University, School of Science and Technology.
    Extraction of grasp-related features by human dual-hand object exploration2009In: 2009 International Conference on Advanced Robotics, Piscataway, NJ: IEEE conference proceedings, 2009, 1-6 p.Conference paper (Refereed)
    Abstract [en]

    We consider the problem of objects exploration for grasping purposes, specifically in cases where vision based methods are not applicable. A novel dual-hand object exploration method is proposed that takes benefits from a human demonstration to enrich knowledge about an object. The user handles an object freely using both hands, without restricting the object pose. A set of grasp-related features obtained during exploration is demonstrated and utilized to generate grasp oriented bounding boxes that are basis for pre-grasp hypothesis. We believe that such exploration done in a natural and user friendly way creates important link between an operator intention and a robot action.

  • 166.
    Charusta, Krzysztof
    et al.
    Örebro University, School of Science and Technology.
    Krug, Robert
    Örebro University, School of Science and Technology.
    Dimitrov, Dimitar
    Örebro University, School of Science and Technology.
    Iliev, Boyko
    Örebro University, School of Science and Technology.
    Independent contact regions based on a patch contact model2012In: 2012 IEEE International Conference on Robotics and Automation (ICRA), IEEE conference proceedings, 2012, 4162-4169 p.Conference paper (Refereed)
    Abstract [en]

    The synthesis of multi-fingered grasps on nontrivial objects requires a realistic representation of the contact between the fingers of a robotic hand and an object. In this work, we use a patch contact model to approximate the contact between a rigid object and a deformable anthropomorphic finger. This contact model is utilized in the computation of Independent Contact Regions (ICRs) that have been proposed as a way to compensate for shortcomings in the finger positioning accuracy of robotic grasping devices. We extend the ICR algorithm to account for the patch contact model and show the benefits of this solution.

  • 167.
    Charusta, Krzysztof
    et al.
    Örebro University, School of Science and Technology.
    Krug, Robert
    Örebro University, School of Science and Technology.
    Stoyanov, Todor
    Örebro University, School of Science and Technology.
    Dimitrov, Dimitar
    Örebro University, School of Science and Technology.
    Iliev, Boyko
    Örebro University, School of Science and Technology.
    Generation of independent contact regions on objects reconstructed from noisy real-world range data2012In: 2012 IEEE International Conference on Robotics and Automation (ICRA), IEEE conference proceedings, 2012, 1338-1344 p.Conference paper (Refereed)
    Abstract [en]

    The synthesis and evaluation of multi-fingered grasps on complex objects is a challenging problem that has received much attention in the robotics community. Although several promising approaches have been developed, applications to real-world systems are limited to simple objects or gripper configurations. The paradigm of Independent Contact Regions (ICRs) has been proposed as a way to increase the tolerance to grasp positioning errors. This concept is well established, though only on precise geometric object models. This work is concerned with the application of the ICR paradigm to models reconstructed from real-world range data. We propose a method for increasing the robustness of grasp synthesis on uncertain geometric models. The sensitivity of the ICR algorithm to noisy data is evaluated and a filtering approach is proposed to improve the quality of the final result.

  • 168.
    Chella, Antonio
    et al.
    Università di Palermo.
    Coradeschi, Silvia
    Örebro University, Department of Technology.
    Frixione, Marcello
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Perceptual anchoring via conceptual spaces2004Conference paper (Refereed)
    Abstract [en]

    Perceptual anchoring is the problem of creating and maintaining in time the connection between symbols and sensor data that refer to the same physical objects. This is one of the facets of the general problem of integrating symbolic and non-symbolic processes in an intelligent system. Gärdenfors' conceptual spaces provide a geometric treatment of knowledge which bridges the gap between the symbolic and sub-symbolic approaches. As such, they can be used for the study of the anchoring problem. In this paper, we propose a computational framework for anchoring based on conceptual spaces. Our framework exploits the geometric structure of conceptual spaces for many of the crucial tasks of anchoring, like matching percepts to symbolic descriptions or tracking the evolution of objects over time.

  • 169.
    Chen, Zetao
    et al.
    The ARC Australian Centre of Excellence for Robotic Vision, Queensland University of Technology, Brisbane, Australia .
    Lowry, Stephanie
    Örebro University, School of Science and Technology.
    Jacobson, Adam
    The ARC Australian Centre of Excellence for Robotic Vision, Queensland University of Technology, Brisbane, Australia .
    Ge, ZongYuan
    The ARC Australian Centre of Excellence for Robotic Vision, Queensland University of Technology, Brisbane, Australia .
    Milford, Michael
    The ARC Australian Centre of Excellence for Robotic Vision, Queensland University of Technology, Brisbane, Australia .
    Distance metric learning for feature-agnostic place recognition2015In: Proceedings of the 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2015, 2556-2563 p.Conference paper (Refereed)
    Abstract [en]

    The recent focus on performing visual navigation and place recognition in changing environments has resulted in a large number of heterogeneous techniques each utilizing their own learnt or hand crafted visual features. This paper presents a generally applicable method for learning the appropriate distance metric by which to compare feature responses from any of these techniques in order to perform place recognition under changing environmental conditions. We implement an approach which learns to cluster images captured at spatially proximal locations under different conditions, separated from frames captured at different places. The formulation is a convex optimization, guaranteeing the existence of a global solution. We evaluate the general applicability of our method on two benchmark change datasets using three typical image pre-processing and feature types: GIST, Principal Component Analysis and learnt Convolutional Neural Network features. The results demonstrate that the distance metric learning approach uniformly improves single-image-based visual place recognition performance across all feature types. Furthermore, we demonstrate that this performance improvement is maintained when the sequence-based algorithm SeqSLAM is applied to the single-image place recognition results, leading to state-of-the-art performance.

  • 170.
    Chen, Zetao
    et al.
    School of Electrical Engineering and Computer Science, Queensland University of Technology, Australia; Australian Centre for Robotic Vision, Queensland University of Technology, Australia.
    Lowry, Stephanie
    School of Electrical Engineering and Computer Science, Queensland University of Technology, Australia.
    Jacobson, Adam
    School of Electrical Engineering and Computer Science, Queensland University of Technology, Australia; Australian Centre for Robotic Vision, Queensland University of Technology, Australia.
    Hasselmo, Michael E.
    Center for Memory and Brain and Graduate Program for Neuroscience, Boston University, United States.
    Milford, Michael
    School of Electrical Engineering and Computer Science, Queensland University of Technology, Australia; Australian Centre for Robotic Vision, Queensland University of Technology, Australia.
    Bio-inspired homogeneous multi-scale place recognition2015In: Neural Networks, ISSN 0893-6080, E-ISSN 1879-2782, Vol. 72, 48-61 p.Article in journal (Refereed)
    Abstract [en]

    Robotic mapping and localization systems typically operate at either one fixed spatial scale, or over two, combining a local metric map and a global topological map. In contrast, recent high profile discoveries in neuroscience have indicated that animals such as rodents navigate the world using multiple parallel maps, with each map encoding the world at a specific spatial scale. While a number of theoretical-only investigations have hypothesized several possible benefits of such a multi-scale mapping system, no one has comprehensively investigated the potential mapping and place recognition performance benefits for navigating robots in large real world environments, especially using more than two homogeneous map scales. In this paper we present a biologically-inspired multi-scale mapping system mimicking the rodent multi-scale map. Unlike hybrid metric-topological multi-scale robot mapping systems, this new system is homogeneous, distinguishable only by scale, like rodent neural maps. We present methods for training each network to learn and recognize places at a specific spatial scale, and techniques for combining the output from each of these parallel networks. This approach differs from traditional probabilistic robotic methods, where place recognition spatial specificity is passively driven by models of sensor uncertainty. Instead we intentionally create parallel learning systems that learn associations between sensory input and the environment at different spatial scales. We also conduct a systematic series of experiments and parameter studies that determine the effect on performance of using different neural map scaling ratios and different numbers of discrete map scales. The results demonstrate that a multi-scale approach universally improves place recognition performance and is capable of producing better than state of the art performance compared to existing robotic navigation algorithms. We analyze the results and discuss the implications with respect to several recent discoveries and theories regarding how multi-scale neural maps are learnt and used in the mammalian brain.

  • 171.
    Cielniak, Grzegorz
    Örebro University, Department of Technology.
    People tracking by mobile robots using thermal and colour vision2007Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This thesis addresses the problem of people detection and tracking by mobile robots in indoor environments. A system that can detect and recognise people is an essential part of any mobile robot that is designed to operate in populated environments. Information about the presence and location of persons in the robot’s surroundings is necessary to enable interaction with the human operator, and also for ensuring the safety of people near the robot.

    The presented people tracking system uses a combination of thermal and colour information to robustly track persons. The use of a thermal camera simplifies the detection problem, which is especially difficult on a mobile platform. The system is based on a fast and efficient samplebased tracking method that enables tracking of people in real-time. The elliptic measurement model is fast to calculate and allows detection and tracking of persons under different views. An explicit model of the human silhouette effectively distinguishes persons from other objects in the scene. Moreover the process of detection and localisation is performed simultaneously so that measurements are incorporated directly into the tracking framework without thresholding of observations. With this approach persons can be detected independently from current light conditions and in situations where other popular detection methods based on skin colour would fail.

    A very challenging situation for a tracking system occurs when multiple persons are present on the scene. The tracking system has to estimate the number and position of all persons in the vicinity of the robot. Tracking of multiple persons in the presented system is realised by an efficient algorithm that mitigates the problems of combinatorial explosion common to other known algorithms. A sequential detector initialises an independent tracking filter for each new person appearing in the image. A single filter is automatically deleted when it stops tracking a person. While thermal vision is good for detecting people, it can be very difficult to maintain the correct association between different observations and persons, especially where they occlude one another, due to the unpredictable appearance and social behaviour of humans. To address these problems the presented tracking system uses additional information from the colour camera. An adaptive colour model is incorporated into the measurement model of the tracker to improve data association. For this purpose an efficient integral image based method is used to maintain the real-time performance of the tracker. To deal with occlusions the system uses an explicit method that first detects situations where people occlude each other. This is realised by a new approach based on a machine learning classifier for pairwise comparison of persons that uses both thermal and colour features provided by the tracker. This information is then incorporated into the tracker for occlusion handling and to resolve situations where persons reappear in a scene.

    Finally the thesis presents a comprehensive, quantitative evaluation of the whole system and its different components using a set of well defined performance measures. The behaviour of the system was investigated on different data sets including different real office environments and different appearances and behaviours of persons. Moreover the influence of all important system parameters on the performance of the system was checked and their values optimised based on these results.

  • 172.
    Cielniak, Grzegorz
    et al.
    Örebro University, Department of Technology.
    Duckett, Tom
    Örebro University, Department of Technology.
    People recognition by mobile robots2004In: Journal of Intelligent & Fuzzy Systems, ISSN 1064-1246, E-ISSN 1875-8967, Vol. 15, no 1, 21-27 p.Article in journal (Refereed)
    Abstract [en]

    This paper addresses the problem of detecting and identifying persons with a mobile robot, by sensory fusion of thermal and colour vision information. In the proposed system, people are first detected with a thermal camera, using image analysis techniques to segment the persons in the thermal images. This information is then used to segment the corresponding regions of the colour images, using an affine transformation to solve the image correspondence between the two cameras. After segmentation, the region of the image containing a person is further divided into regions corresponding to the person's head, torso and legs. Temperature and colour features are then extracted from each region for input to a pattern recognition system. Three alternative classfication methods were investigated in experiments with a moving mobile robot and moving persons in an office environment. The best identification performance was obtained with a dynamic recognition method based on a Bayes classifier, which takes into account evidence accumulated in a sequence of images.

  • 173.
    Cielniak, Grzegorz
    et al.
    Lincoln Univ, Sch Comp Sci, Lincoln, Lincs LN6 7TS, England.
    Duckett, Tom
    Lincoln Univ, Sch Comp Sci, Lincoln, Lincs LN6 7TS, England.
    Lilienthal, Achim J.
    Örebro University, School of Science and Technology.
    Data association and occlusion handling for vision-based people tracking by mobile robots2010In: Robotics and Autonomous Systems, ISSN 0921-8890, E-ISSN 1872-793X, Vol. 58, no 5, 435-443 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents an approach for tracking multiple persons on a mobile robot with a combination of colour and thermal vision sensors, using several new techniques. First, an adaptive colour model is incorporated into the measurement model of the tracker. Second, a new approach for detecting occlusions is introduced, using a machine learning classifier for pairwise comparison of persons (classifying which one is in front of the other). Third, explicit occlusion handling is incorporated into the tracker. The paper presents a comprehensive, quantitative evaluation of the whole system and its different components using several real world data sets. (C) 2010 Elsevier B.V. All rights reserved.

  • 174.
    Cielniak, Grzegorz
    et al.
    Örebro University, Department of Technology.
    Miladinovic, Mihajlo
    Hammarin, Daniel
    Göransson, Linus
    Lilienthal, Achim J.
    Örebro University, Department of Technology.
    Duckett, Tom
    Örebro University, Department of Technology.
    Appearance-based tracking of persons with an omnidirectional vision sensor2003Conference paper (Refereed)
    Abstract [en]

    This paper addresses the problem of tracking a moving person with a single, omnidirectional camera. An appearance-based tracking system is described which uses a self-acquired appearance model and a Kalman filter to estimate the position of the person. Features corresponding to ``depth cues'' are first extracted from the panoramic images, then an artificial neural network is trained to estimate the distance of the person from the camera. The estimates are combined using a discrete Kalman filter to track the position of the person over time. The ground truth information required for training the neural network and the experimental analysis was obtained from another vision system, which uses multiple webcams and triangulation to calculate the true position of the person. Experimental results show that the tracking system is accurate and reliable, and that its performance can be further improved by learning multiple, person-specific appearance models

  • 175.
    Cielniak, Grzegorz
    et al.
    Örebro University, Department of Technology.
    Treptow, André
    University of Tübingen.
    Duckett, Tom
    Örebro University, Department of Technology.
    Quantitative performance evaluation of a people tracking system on a mobile robot2005Conference paper (Refereed)
    Abstract [en]

    Future service robots will need to keep track of the persons in their environment. A number of people tracking systems have been developed for mobile robots, but it is currently impossible to make objective comparisons of their performance. This paper presents a comprehensive, quantitative evaluation of a state-of-the-art people tracking system for a mobile robot in an office environment, for both single and multiple persons.

  • 176.
    Cirillo, Marcello
    Örebro University, School of Science and Technology.
    Planning in Inhabited Environments: Human-Aware Task Planning and Activity Recognition2010Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Promised some decades ago by researchers in artificial intelligence and robotics as an imminent breakthrough in our everyday lives, a robotic assistant that could work with us in our home and our workplace is a dream still far from being fulfilled. The work presented in this thesis aims at bringing this future vision a little closer to realization. Here, we start from the assumption that an efficient robotic helper should not impose constraints on users' activities, but rather perform its tasks unobtrusively to fulfill its goals and to facilitate people in achieving their objectives.  Also, the helper should be able to consider the outcome of possible future actions by the human users, to assess how those would affect the environment with respect to the agent's objectives, and to predict when its support will be needed. In this thesis we address two highly interconnected problems that are essential for the cohabitation of people and service robots: robot task planning and human activity recognition. First, we present human-aware planning, that is, our approach to robot high-level symbolic reasoning for plan generation. Human-aware planning can be applied in situations where there is a controllable agent, the robot, whose actions we can plan, and one or more uncontrollable agents, the human users, whose future actions we can only try to predict. In our approach, therefore, the knowledge of the users' current and future activities is an important prerequisite. We define human-aware as a new type of planning problem, we formalize the extensions needed by a classical planner to solve such a problem, and we present the implementation of a planner that satisfies all identified requirements. In this thesis we explore also a second issue, which is a prerequisite to the first one: human activity monitoring in intelligent environments. We adopt a knowledge driven approach to activity recognition, whereby a constraint-based domain description is used to correlate sensor readings to human activities. We validate our solutions to both human-aware planning and activity recognition both theoretically and experimentally, describing a number of explanatory examples and test runs in a real environment.

  • 177.
    Cirillo, Marcello
    et al.
    Örebro University, School of Science and Technology.
    Karlsson, Lars
    Örebro University, School of Science and Technology.
    Saffiotti, Alessandro
    Örebro University, School of Science and Technology.
    A framework for human-aware robot planning2008In: Tenth Scandinavian conference on artificial intelligence / [ed] A. Holst, P. Kreuger, P. Funk, Amsterdam: IOS press , 2008, 52-59 p.Conference paper (Refereed)
    Abstract [en]

    Robots that share their workspace with humans, like household or service robots, need to take into account the presence of humans when planning their actions. In this paper, we present a framework for human-aware planning in which we consider three kinds of human-robot interaction. We focus in particular on the core module of the framework, a human-aware planner that generates a sequence of actions for a robot, taking into account the status of the environment, the goals of the robot and the forecasted plan of the human. We present a first realization of this planner, together with two simple experiments that demonstrate the feasibility of our approach.

  • 178.
    Cirillo, Marcello
    et al.
    Örebro University, School of Science and Technology.
    Karlsson, Lars
    Örebro University, School of Science and Technology.
    Saffiotti, Alessandro
    Örebro University, School of Science and Technology.
    A human-aware robot task planner2009In: Proceedings of the 19th international conference on automated planning and scheduling, ICAPS 2009 / [ed] Alfonso Gerevini, Adele Howe, Amedeo Cesta, Ioannis Refanidis, Menlo Park: AAAI press , 2009, 58-65 p.Conference paper (Refereed)
    Abstract [en]

    The growing presence of household robots in inhabited environments arises the need for new robot task planning techniques. These techniques should take into consideration not only the actions that the robot can perform or unexpected external events, but also the actions performed by a human sharing the same environment, in order to improve the cohabitation of the two agents, e.g., by avoiding undesired situations for the human. In this paper, we present a human-aware planner able to address this problem. This planner supports alternative hypotheses of the human plan, temporal duration for the actions of both the robot and the human, constraints on the interaction between robot and human, partial goal achievement and, most importantly, the possibility to use observations of human actions in the policy generated for the robot. The planner has been tested as a standalone component and in conjunction with our framework for human-robot interaction in a real environment.

  • 179.
    Cirillo, Marcello
    et al.
    Örebro University, School of Science and Technology.
    Karlsson, Lars
    Örebro University, School of Science and Technology.
    Saffiotti, Alessandro
    Örebro University, School of Science and Technology.
    Human-aware planning for robots embedded in ambient ecologies2012In: Pervasive and Mobile Computing, ISSN 1574-1192, E-ISSN 1873-1589, Vol. 8, no 4, 542-561 p.Article in journal (Refereed)
    Abstract [en]

    We address the issue of human-robot cohabitation in smart environments. In particular, the presence of humans in a robot's work space has a profound influence on how the latter should plan its actions. We propose the use of Human-Aware Planning, an approach in which the robot exploits the capabilities of a sensor-rich environment to obtain information about the (current and future) activities of the people in the environment, and plans its tasks accordingly.

    Here, we formally describe the planning problem behind our approach, we analyze its complexity and we detail the algorithm of our planner. We then show two application scenarios that could benefit from the techniques described. The first scenario illustrates the applicability of human-aware planning in a domestic setting, while the second one illustrates its use for a robotic helper in a hospital. Finally, we present a five hour-long test run in a smart home equipped with real sensors, where a cleaning robot has been deployed and where a human subject is acting. This test run in a real setting is meant to demonstrate the feasibility of our approach to human-robot interaction.

  • 180.
    Cirillo, Marcello
    et al.
    Örebro University, School of Science and Technology.
    Karlsson, Lars
    Örebro University, School of Science and Technology.
    Saffiotti, Alessandro
    Örebro University, School of Science and Technology.
    Human-aware task planning: an application to mobile robots2010In: ACM transactions on intelligent systems and technology, ISSN 2157-6904, Vol. 1, no 2, Article 15- p.Article in journal (Refereed)
    Abstract [en]

    Consider a house cleaning robot planning its activities for the day. Assume that the robot expects the human inhabitant to first dress, then have breakfast, and finally go out. Then, it should plan not to clean the bedroom while the human is dressing, and to clean the kitchen after the human has had breakfast. In general, robots operating in inhabited environments, like households and future factory floors, should plan their behavior taking into account the actions that will be performed by the humans sharing the same environment. This would improve human-robot cohabitation, for example, by avoiding undesired situations for the human. Unfortunately, current task planners only consider the robot's actions and unexpected external events in the planning process, and cannot accommodate expectations about the actions of the humans.

    In this article, we present a human-aware planner able to address this problem. Our planner supports alternative hypotheses of the human plan, temporal duration for the actions of both the robot and the human, constraints on the interaction between robot and human, partial goal achievement and, most importantly, the possibility to use observations of human actions in the policy generated for the robot. Our planner has been tested both as a stand-alone component and within a full framework for human-robot interaction in a real environment.

  • 181.
    Cirillo, Marcello
    et al.
    Örebro University, School of Science and Technology.
    Karlsson, Lars
    Örebro University, School of Science and Technology.
    Saffiotti, Alessandro
    Örebro University, School of Science and Technology.
    Human-aware task planning for mobile robots2009In: Proceedings of the 5th international conference on advanced robotics, ICAR 2009, New York: IEEE conference proceedings, 2009, 172-178 p.Conference paper (Refereed)
    Abstract [en]

    Robots that share their workspace with people, like household or service robots, need to take into account the presence of humans when planning their actions. In this paper, we present a framework for human-aware planning that would make the robots capable of performing their tasks without interfering with the user in his every day life. We focus in particular on the core module of the framework, a humanaware planner that generates a sequence of actions for a robot, taking into account the state of the environment and the goals of the robot, together with a set of forecasted possible plans of the human. We describe the planner and its relations to other system components like a plan recognizer, and present a series of experiments performed with a household robot in a small apartment.

  • 182.
    Cirillo, Marcello
    et al.
    Örebro University, School of Science and Technology.
    Lanzellotto, Federica
    Roma 3 University, Rome, Italy.
    Pecora, Federico
    Örebro University, School of Science and Technology.
    Saffiotti, Alessandro
    Örebro University, School of Science and Technology.
    Monitoring domestic activities with temporal constraints and components2009In: Intelligent environments 2009 / [ed] V. Callaghan, A. Kameas, A. Reyes, D. Royo, M. Weber, Amsterdam: IOS Press, 2009, 117-124 p.Conference paper (Refereed)
    Abstract [en]

    Intelligent environments are increasingly rich in ubiquitous sensing capabilities that can be leveraged to know which actions a user is engaged in at any given moment in time. The ability of an intelligent environment to recognize a high-level plan of activities performed by the user in a smart home would allow to construct proactive services, such as reminding, forecasting and providing timely physical support. This article proposes an approach to human activity recognition based on temporal planning. The approach leverages on one hand the ubiquitous sensors provided by the PEIS-Home, a sensor-rich intelligent environment, and, on the other hand, the temporal representation and reasoning capabilities of OMPS, a constraint-based temporal planning and scheduling framework.

  • 183.
    Conti, Mauro
    et al.
    Department of Mathematics, University of Padua, Padua, Italy.
    Dragoni, Nicola
    Örebro University, School of Science and Technology. DTU Compute, Technical University of Denmark (DTU), Kgs. Lyngby, Denmark.
    Lesyk, Viktor
    DTU Compute, Technical University of Denmark (DTU), Kgs. Lyngby, Denmark; Centre for Applied Autonomous Sensor Systems (AASS), Örebro University, Örebro, Sweden.
    A Survey of Man In The Middle Attacks2016In: IEEE Communications Surveys and Tutorials, ISSN 1553-877X, E-ISSN 1553-877X, Vol. 18, no 3, 2027-2051 p.Article in journal (Refereed)
    Abstract [en]

    The Man-In-The-Middle (MITM) attack is one of the most well known attacks in computer security, representing one of the biggest concerns for security professionals. MITM targets the actual data that flows between endpoints, and the confidentiality and integrity of the data itself. In this paper, we extensively review the literature on MITM to analyse and categorize the scope of MITM attacks, considering both a reference model, such as the open systems interconnection (OSI) model, as well as two specific widely used network technologies, i.e., GSM and UMTS. In particular, we classify MITM attacks based on several parameters, like location of an attacker in the network, nature of a communication channel, and impersonation techniques. Based on an impersonation techniques classification, we then provide execution steps for each MITM class. We survey existing countermeasures and discuss the comparison among them. Finally, based on our analysis, we propose a categorisation of MITM prevention mechanisms, and we identify some possible directions for future research.

  • 184.
    Coradeschi, Silvia
    et al.
    Örebro University, School of Science and Technology.
    Cortellessa, GabriellaKristoffersson, AnnicaÖrebro University, School of Science and Technology.Loutfi, AmyÖrebro University, School of Science and Technology.
    Proceedings of the Ro-man 2012 Workshop on Social Robotics Telepresence2012Conference proceedings (editor) (Other academic)
  • 185.
    Coradeschi, Silvia
    et al.
    School of Science and Technology, Örebro University, Örebro, Sweden.
    Cortellessa, GabriellaCNR - National Research Council of Italy, Istituto di Scienze e Tecnologie della Cognizione, Rome, Italy.Kristoffersson, AnnicaÖrebro University, School of Science and Technology.Loutfi, AmyÖrebro University, School of Science and Technology.Severinson Eklundh, KerstinCI Group, CSC, KTH Royal Institute of Technology, Stockholm, Sweden.
    Proceedings of the 2011 HRI Workshop on Social Robotic Telepresence2011Conference proceedings (editor) (Other academic)
  • 186.
    Coradeschi, Silvia
    et al.
    Örebro University, Department of Technology.
    Driankov, Dimiter
    Örebro University, Department of Technology.
    Karlsson, Lars
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Fuzzy anchoring2001In: The 10th IEEE international conference on fuzzy systems, 2001, 111-114 p.Conference paper (Refereed)
    Abstract [en]

    An intelligent physical agent must incorporate motor and perceptual processes to interface with the physical world, and abstract cognitive processes to reason about the world and the options available. One crucial aspect of incorporating cognitive processes into a physically embedded reasoning system is the integration between the symbols used by the reasoning processes to denote physical objects, and the perceptual data corresponding to these objects. We treat this integration aspect by proposing a fuzzy computational theory of anchoring. Anchoring is the process of creating and maintaining the correspondence between symbols and percepts that refer to the same physical objects. Modeling this process using fuzzy set-theoretic notions enables dealing with perceptual data that can be affected by uncertainty/imprecision and imprecise/vague linguistic descriptions of objects

  • 187.
    Coradeschi, Silvia
    et al.
    Örebro University, School of Science and Technology.
    Kristoffersson, Annica
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Von Rump, Stephen
    Cesta, Amedeo
    Cortellessa, Gabriella
    Gonzalez, Javier
    Towards a methodology for longitudinal evaluation of social robotic telepresence for elderly2011In: 1st Workshop on Social Robotic Telepresence at HRI 2011, 2011Conference paper (Refereed)
    Abstract [en]

    This paper describes a methodology for performing longitudinal evaluations when a social robotic telepresence system is deployed in realistic environments. This work is the core of an Ambient Assisted Living Project called ExCITE, Enabling Social Interaction Through Telepresence. The ExCITE project is geared towards an elderly audience and has as aim to increase social interaction among elderly, their family and healthcare services by using robotic telepresence. The robotic system used in the project is called the Giraff robot and over a three year period, prototypes of this platform are deployed at a number of test-sites in different European countries where user feedback is collected and fedback into the refinement of the prototype. In this paper, we discuss the methodology of ExCITE in particular relation to other methodologies for longitudinal evaluation. The paper also provides a discussion of the possible pitfalls and risks in performing longitudinal studies of this nature particularly as they relate to social robotic telepresence technologies.

  • 188.
    Coradeschi, Silvia
    et al.
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    A review of Past and Future Trends in Perceptual Anchoring2008In: Tools in Artificial Intelligence, Vienna: I-Tech Eduacation and Publishing , 2008Chapter in book (Other academic)
  • 189.
    Coradeschi, Silvia
    et al.
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Kristoffersson, Annica
    Cortellessa, Gabriella
    Severinson Eklundh, Kerstin
    KTH.
    Social robotic telepresence2011In: HRI '11: proceedings of the 6th international conference on Human-robot interaction, 2011, 5-6 p.Conference paper (Refereed)
  • 190.
    Coradeschi, Silvia
    et al.
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    An introduction to the anchoring problem2003In: Robotics and Autonomous Systems, ISSN 0921-8890, E-ISSN 1872-793X, Vol. 43, no 2-3, 85-96 p.Article in journal (Refereed)
    Abstract [en]

    Anchoring is the problem of connecting, inside an artificial system, symbols and sensor data that refer to the same physical objects in the external world. This problem needs to be solved in any robotic system that incorporates a symbolic component. However, it is only recently that the anchoring problem has started to be addressed as a problem per se, and a few general solutions have begun to appear in the literature. This paper introduces the special issue on perceptual anchoring of the Robotics and Autonomous Systems journal. Our goal is to provide a general overview of the anchoring problem, and to highlight some of its subtle points

  • 191.
    Coradeschi, Silvia
    et al.
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Anchoring symbols to sensor data: preliminary report2000In: Proceedings of the 17th AAAI conference, 2000, 129-135 p.Conference paper (Refereed)
    Abstract [en]

    Anchoring is the process of creating and maintaining the correspondence between symbols and percepts that refer to the same physical objects. Although this process must necessarily be present in any physically embedded system that includes a symbolic component (e.g., an autonomous robot), no systematic study of anchoring as a problem per se has been reported in the literature on intelligent systems. In this paper, we propose a domain-independent definition of the anchoring problem, and identify its three basic functionalities: find, reacquire, and track. We illustrate our definition on two systems operating in two different domains: an unmanned airborne vehicle for traffic surveillance; and a mobile robot for office navigation.

  • 192.
    Coradeschi, Silvia
    et al.
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Anchoring symbols to vision data by fuzzy logic1999In: Symbolic and quantitative approaches to reasoning and uncertainty: European conference, ECSQARU '99 : proceedings / [ed] Anthony Hunter, Simon Parsons, Berlin/Heidelberg: Springer Berlin/Heidelberg, 1999, 104-115 p.Conference paper (Refereed)
    Abstract [en]

    Intelligent agents embedded in physical environments need the ability to connect, or anchor, the symbols used to perform abstract reasoning to the physical entities which these symbols refer to. Anchoring must rely on perceptual data which is inherently affected by uncertainty. We propose an anchoring technique based on the use of fuzzy sets to represent uncertainty, and of degree of subset-hood to compute the partial match between signatures of objects. We show examples where we use this technique to allow a deliberative system to reason about the objects (cars) observed by a vision system embarked in an unmanned helicopter, in the framework of the WITAS project.

  • 193.
    Coradeschi, Silvia
    et al.
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Perceptual anchoring:  a key concept for plan execution in embedded systems2002In: Advances in Plan-Based Control of Robotic Agents / [ed] Michael Beetz, Joachim Hertzberg, Malik Ghallab, Martha E. Pollack, 2002, Vol. 2466, 97-126 p.Conference paper (Refereed)
    Abstract [en]

    Anchoring is the process of creating and maintaining the correspondence between symbols and percepts that refer to the same physical objects. This process must necessarily be present in any physically embedded system that includes a symbolic component, for instance, in an autonomous robot that uses a planner to generate strategic decisions. However, no systematic study of anchoring as a problem per se has been reported in the literature on intelligent systems. In this paper, we advocate for the need for a domain-independent framework to deal with the anchoring problem, and we report some initial steps in this direction. We illustrate our arguments and framework by showing experiments performed on a real mobile robot

  • 194.
    Coradeschi, Silvia
    et al.
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Perceptual anchoring of symbols for action2001In: Proceedings of the 17th IJCAI, 2001, 407-412 p.Conference paper (Refereed)
    Abstract [en]

    Anchoring is the process of creating and maintaining the correspondence between symbols and percepts that refer to the same physical objects. Although this process must necessarily be present in any symbolic reasoning system embedded in a physical environment (e.g., an autonomous robot), the systematic study of anchoring as a clearly separated problem is just in its initial phase. In this paper we focus on the use of symbols in actions and plans and the consequences this has for anchoring. In particular we introduce action properties and partial matching of objects descriptions. We also consider the use of indefinite references in the context of action. The use of our formalism is exemplified in a mobile robotic domain

  • 195.
    Coradeschi, Silvia
    et al.
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    Perceptual anchoring with indefinite descriptions2003Conference paper (Refereed)
    Abstract [en]

    Anchoring is the problem of how to connect, inside an artificial system, the symbol-level and signal-level representations of the same physical object. In most previous work on anchoring, symbol-level representations were meant to denote one specific object, like 'the red pen p22'. These are also called definite descriptions. In this paper, we study anchoring in the case of indefinite descriptions, like `a red pen x'. A key point of our study is that anchoring with an indefinite description involves, in general, the selection of one object among several perceived objects that satisfy that description. We analyze several strategies to perform object selection, and compare them with the problem of action selection in autonomous embedded agents.

  • 196. Cortellessa, Gabriella
    et al.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Pecora, Federico
    Örebro University, School of Science and Technology.
    An on-going evaluation of domestic robots2008In: Robotic helpers: user interaction, interfaces and companions in assistive and therapy robotics, 2008, 87-91 p.Conference paper (Refereed)
    Abstract [en]

    In this position paper we describe an on-going effort to provide an in-depth and cross-cultural evaluation of how elderly users perceive robotic systems for domestic cognitive support. Our work is grounded on two implemented smarthome prototypes, namely the RoboCare Smart Home developed in Italy, and the PEIS Home developed in Sweden. The former project has provided a testbed for an a-posteriori evaluation of smart home technology with Italian user groups. The presence in Sweden of the PEIS Home, a system which shares numerous commonalities with the RoboCare Smart Home, gives us the opportunity to extend these results by (1) providing a cross-cultural perspective on the perception of smart home technology, and (2) lay the foundations for a live, Wizard of Oz based evaluation within the PEIS Home.

     

  • 197. Cortellessa, Gabriella
    et al.
    Scopelliti, Massimiliano
    Tiberio, Lorenza
    Koch Svedberg, Gion
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Pecora, Federico
    Örebro University, School of Science and Technology.
    A cross-cultural evaluation of domestic assistive robots2008In: AAAI fall symposium: technical report, v FS-08-02, American Association for Artificial Intelligence , 2008, 24-31 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents the first steps in a series of on-going user evaluations of intelligent environments for supporting elderly users at home. We specifically focus on a comparison of elderly perceptions of social assistive domestic robots between Italian and Swedish user groups. The evaluation was carried out in Rome, Italy and O¨ rebro, Sweden, including surrounding towns. The results, obtained through a videobased methodology, highlight the variety in level of appreciation of domestic robots for elderly care as it relates to a number of aspects of culture which are not necessarily trivial to identify. Our results suggest some specific factors as important for interpreting the difference in perception, e.g., the user’s acquaintance with ICT (Information and Communication Technology) and the social policies implemented in the two countries. Also, the results show interesting commonalities, such as the general agreement among Swedish and Italian user groups on the physical aspect of the robot.

  • 198.
    d. C. Silva-Lopez, Lia Susana
    et al.
    Örebro University, School of Science and Technology.
    Broxvall, Mathias
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Karlsson, Lars
    Örebro University, School of Science and Technology.
    Towards configuration planning with partially ordered preferences: representation and results2015In: Künstliche Intelligenz, ISSN 0933-1875, E-ISSN 1610-1987, Vol. 9, no 2, 173-183 p.Article in journal (Refereed)
    Abstract [en]

    Configuration planning for a distributed robotic system is the problem of how to configure the system over time in order to achieve some causal and/or information goals. A configuration plan specifies what components (sensor, actuator and computational devices), should be active at different times and how they should exchange information. However, not all plans that solve a given problem need to be equally good, and for that purpose it may be important to take preferences into account. In this paper we present an algorithm for configuration planning that incorporates general partially ordered preferences. The planner supports multiple preference categories, and hence it solves a multiple-objective optimization problem: for a given problem, it finds all possible valid, non-dominated configuration plans. The planner has been able to successfully cope with partial ordering relations between quantitative preferences in practically acceptable times, as shown in the empirical results. Preferences here are represented as c-semirings, and are used for establishing dominance of a solution over another in order to obtain a set of configuration plans that will constitute the solution of a configuration planning problem with partially ordered preferences. The dominance operators tested in this paper are Pareto and Lorenz dominance. Our solver considers one guiding heuristic for obtaining the first solution, and then switches to a dominance based monotonically decreasing heuristic used for pruning dominated partial configuration plans. In our empirical results, we perform a statistical study in the space of problem instances and establish families of problems for which our approach is computationally feasible.

  • 199.
    Dahlbom, Anders
    Örebro University, School of Science and Technology.
    Petri nets for situation recognition2011Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Situation recognition is a process with the goal of identifying a priori defined situations in a flow of data and information. The purpose is to aid decision makers with focusing on relevant information by filtering out situations of interest. This is an increasingly important and non trivial problem to solve since the amount of information in various decision making situations constantly grow. Situation recognition thus addresses the information gap, i.e. the problem of finding the correct information at the correct time. Interesting situations may also evolve over time and they may consist of multiple participating objects and their actions. This makes the problem even more complex to solve. This thesis explores situation recognition and provides a conceptualization and a definition of the problem, which allow for situations of partial temporal definition to be described. The thesis then focuses on investigating how Petri nets can be used for recognising situations. Existing Petri net based approaches for recognition have some limitations when it comes to fulfilling requirements that can be put on solutions to the situation recognition problem. An extended Petri net based technique that addresses these limitations is therefore introduced. It is shown that this technique can be as efficient as a rule based techniques using the Rete algorithm with extensions for explicitly representing temporal constraints. Such techniques are known to be efficient; hence, the Petri net based technique is efficient too. The thesis also looks at the problem of learning Petri net situation templates using genetic algorithms. Results points towards complex dynamic genome representations as being more suited for learning complex concepts, since these allow for promising solutions to be found more quickly compared with classical bit string based representations. In conclusion, the extended Petri net based technique is argued to offer a viable approach for situation recognition since it: (1) can achieve good recognition performance, (2) is efficient with respect to time, (3) allows for manually constructed situation templates to be improved and (4) can be used with real world data to find real world situations.

  • 200.
    Dandan, Kinan
    et al.
    Örebro University, School of Science and Technology.
    Albitar, Houssam
    Örebro University, School of Science and Technology.
    Ananiev, Anani
    Örebro University, School of Science and Technology.
    Kalaykov, Ivan
    School of Science and Technology, Örebro University, Örebro Sweden.
    Confined Spaces: Cleaning Techniques and Robot-based Surface Cleaning2016In: American Scientific Research Journal for Engineering, Technology and Science, ISSN 2313-4402, Vol. 22, no 1, 210-230 p.Article in journal (Refereed)
    Abstract [en]

    The requirements of the working and safety norms demonstrate significant need of increased efficiency and improved working conditions in cleaning confined spaces. This paper presents an overview of the existing technologies and solutions for cleaning large confined spaces. A special attention is directed for cleaning interior surface of confined spaces used mainly for storing bulk materials or liquids, such as silos. The cleaning technologies for confined space depend on several aspects as the build-up material, the surface material, the ambient conditions. Four cleaning techniques are presented in this paper. The mechanisms and robots related to the studied problem are surveyed and evaluated from the viewpoint of their capability to clean interior surfaces. The dominating majority of the existing cleaning equipment is constructed to serve cleaning the entire volume of the respective confined space (silo), but not for cleaning the interior surface.

1234567 151 - 200 of 815
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf