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  • 1.
    Akbari, Haris
    et al.
    Örebro University, School of Science and Technology.
    Amel, Hadzic
    Svensk vindkraft2012Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
  • 2.
    Elshani, Triumf
    Örebro University, School of Science and Technology.
    SKOTTSTÄLLNING AV ÖVNINGSVAPEN TILL GRANATGEVÄR CARL GUSTAF2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This 15 point thesis is carried out at Saab Dynamics AB in Karlskoga. The company produces defense material aimed at the Swedish market and for export.

    The task was to make a survey of the current zeroing procedure for Sub Caliber Adapter for 84 mm recoilless rifle Carl Gustaf, and to examine the accuracy of the tools used today for zeroing.

    Measurements performed show that some of the tools has good accuracy for zeroing of Sub Caliber Adapter 20 mm withe other tools are not so good. The accuracy for zeroing of Sub Caliber Adapter 7.62 mm is not sufficient

    With a suitable design it is possible to produce tools with good accuracy for zeroing of Sub Caliber Adapters.

  • 3.
    Erdis, Sahit
    Örebro University, School of Science and Technology.
    Robot-Assisted Hospital Bed Transport2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The controlling of mobile robots has been and still is in the focus of researchers. Fuzzy rule-based controllers are extensively used to control robots. Path planners were created using different search methods finding the shortest  trajectory between two points and thereby avoiding recorded obstacles. The low degree of automation in hospitals promises huge potential for increasing logistical effects by the use of mobile robots. Especially the automated transport of a hospital bed, which manually requires two persons, would release time from transportation activities. The usage of a mobile robot joined to a hospital bed makes controlling considerably harder. This document describes a project accomplished by me in cooperation with RobCab AB. During the project, a path planner was created and controlling strategies to move a mobile robot joined to a hospital bed between two locations was implemented. The controlling strategies are not only based on sensor readings from a laser mounted on the mobile robot and a list of way points provided by a path planner but incorporates also the position of the bed in the environment. The robot adapts its behavior to ensure a safe movement considering the position of the bed which is not only determined by the kinematics of the robot-bed model but also by an external force in the form of a person following the transport (human intelligence). Development was done on the Stage simulator and is intended to be finally transferred to a real robot platform. Tests done in the simulator showed that the implemented methods are applicable to bring the bed to the desired goal taking into account the reaction of the person following the transport.

  • 4.
    Hansson, Magnus
    Örebro University, Örebro University School of Business.
    From dusk till dawn: three essays on organizational closedowns2005Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis present three essays on organizational closedowns, where productivity effects under uncertainty and threat on the single-firm level is in focus. On a broad level, this thesis aims to develop better explanations of the process of organizational closedowns. More specific, this thesis aims to outline a theoretical foundation for studies of organizational closedowns, unfold a closedown process and extend the explanations of productivity effects during closedowns, in different contexts. This is done in three essays on organizational closedowns.

     

    These three essays have different methodological settings and it is argued that it is through the application of a variety of methods, that strength is obtained and supportive to the explorative endeavor that was carried out. The first essay is based on a critical review approach of the classical Hawthorne experiments. The second essay is based on a single case-study and the third on a multiple case-study in combination with a statistical analysis of the productivity development during the closedown processes.

     

    In the first essay of this thesis a theoretical foundation is outlined from a recontextualization of the Hawthorne experiments that serve as a base for the following essays. By applying a closedown perspective, it is possible to view the Hawthorne experiments from a new perspective, where it is claimed that there are several similarities to these experiments and situations where a threat of or decision to closedown is present. The Hawthorne experiments were initially seen as a closed system, laboratory experiments instead of action experiments of daily operations. Analyzing the prevalent threat, in both the Hawthorne experiments and the settings where the Horndal as well as the Closedown effect have been observed it has been evident that productivity has increased. Threat can act as both a motivator and demotivator, and as shown in research on the Closedown effect, employees become sensitive to the managerial setting and information provided, why productivity tend to fluctuate. It is argued that the Closedown effect is a productivity increase effect that occurs, considering the entire closedown period.

     

    In the second essay a single case study of a single-plant closure is unfolded. By following the closedown process of the firm critical events are tracked in order to explain the fluctuations in productivity. Throughout the closedown process productivity continued to increase as well as an all-time high was recorded. It was evident from this case study that the workers are highly sensitive to the management’s actions and way of providing information. The retrenchment program that was offered to the workers was of high importance in the initial phase of the closedown process, whereas it became diminishing in the latter phases. Supporting findings of previous research uncovered changes in psychological responses, structural settings, changes in cognitive and motivational manifestations as well as behavioral consequences. Increases in the operative space of the workers, innovative skills, workers autonomy, efforts and productivity were distinct behavioral consequences of closedown decision and develop during the closedown process. From this study both an empirical and a theoretical model for further research is suggested.

     

    In the third essay of this thesis a multiple case-study is presented. Contrary to the case study presented in the second essay these cases are characterized by a Non-Social responsible managerial setting. That is, the management did not provide any supportive activities for the workers in the closedown process. The Closedown effect is statistically significant in all the cases. There is a need for an analytical distinction of the phases of the closedown process, in terms of the primary advanced notice period and the secondary countdown period. Based on the analysis, and with this distinction, we are able to conclude that the productivity increase effect can be anticipated during the countdown period. From this article a theoretical elaboration on both the Closedown effect as well as distinctions on certain terms valid for a detailed analysis of the closedown process is provided.

     

    From the three essays the results are distilled as they are discussed respectively according to the theoretical and the empirical conclusions. From this the interrelationship between the results of the essays are discusses divided according to the managerial behavior, individual behavior and productivity development. In addition, a separate section presents the normative and practical implications from this research. At end and in line with a methodological triangulation the discussion on suggestions for further research provide a range of potent alternatives on future research on organizational closedowns.

    List of papers
    1. Recontextualizing the Hawthorne effect
    Open this publication in new window or tab >>Recontextualizing the Hawthorne effect
    2006 (English)In: Scandinavian Journal of Management, ISSN 0956-5221, E-ISSN 1873-3387, Vol. 22, no 2, p. 120-137Article in journal (Refereed) Published
    Abstract [en]

    In this paper, we explore the thesis that a threat to the vital interests of an entity, be it a single individual or a group, will lead to productivity increases in a variety of forms. We argue that because threat was present in the Hawthorne experiments, the adoption of a decline perspective is relevant to a recontextualization of the Hawthorne effect. This means introducing aspects of an open systems approach into the analysis. A comparison between the Hawthorne effect and the Closedown and Horndal effects reveals certain analytical similarities. In view of this, and because the threat factor is present in the Hawthorne experiments, we recommend that threat be taken into account as one component of the Hawthorne effect

    Keywords
    Closedown effect, Hawthorne effect, Horndal effect, Productivity, Threat, Decline
    National Category
    Business Administration
    Research subject
    Business Studies
    Identifiers
    urn:nbn:se:oru:diva-2926 (URN)10.1016/j.scaman.2005.12.003 (DOI)
    Available from: 2008-03-05 Created: 2008-03-05 Last updated: 2019-03-26Bibliographically approved
    2. Pyrrhic victories: anticipating the closedown effect 
    Open this publication in new window or tab >>Pyrrhic victories: anticipating the closedown effect 
    2006 (English)In: International Journal of Human Resource Management, ISSN 0958-5192, E-ISSN 1466-4399, Vol. 17, no 5, p. 938-958Article in journal (Refereed) Published
    Abstract [en]

    Previous studies with empirical evidence on social responsible driven closedowns have identified a productivity increase effect that occurs during the process of organizational closedowns, known as the closedown effect. Our proposition is that this effect can be anticipated as a consequence of a closedown decision. Encountering four different non social responsible closedown cases, of various durations, we statistically test this proposition. Further, we identify a need for an analytical distinction of the phases of the closedown process, in terms of the primary 'advanced notice period' and the secondary 'countdown period'. Based on the analysis, and with this distinction, we are able to conclude that the productivity increase effect can be anticipated during the countdown period. The comparably longer time frame in the Studding case provides the strongest support for our proposition. From the analysis we suggest hypotheses for further research.

    Keywords
    Decline; closedown; closedown effect; productivity; social responsibility
    National Category
    Business Administration
    Research subject
    Business Studies
    Identifiers
    urn:nbn:se:oru:diva-2927 (URN)10.1080/09585190600641255 (DOI)
    Available from: 2008-03-05 Created: 2008-03-05 Last updated: 2019-03-26Bibliographically approved
    3. When the lights go out
    Open this publication in new window or tab >>When the lights go out
    (English)Manuscript (preprint) (Other academic)
    National Category
    Business Administration
    Research subject
    Business Studies
    Identifiers
    urn:nbn:se:oru:diva-2929 (URN)
    Available from: 2008-03-05 Created: 2008-03-05 Last updated: 2019-03-26Bibliographically approved
  • 5.
    Kjellander, Johan
    Örebro University, Department of Technology.
    Interactive generic product modeling based on a procedural language2001Report (Other academic)
    Abstract [en]

    Text-based, language driven user interfaces were common in the early days of Computer Aided Design. Commands were often assembled into part programs and executed in batch mode. Even if these systems were complicated to use they did offer interesting features. This paper discusses the problem of designing a language-based modeling system which is interactive and has a graphical user interface. The Varkon system (4) is used to illustrate how some of the difficulties can be overcome.

  • 6.
    Larsson, Johan
    Örebro University, Department of Technology.
    Reactive navigation of an autonomous vehicle in underground mines:  2007Licentiate thesis, monograph (Other academic)
    Abstract [en]

    In most underground mines, LHD (Load-Haul-Dump) vehicles are used to transportore from the stope or muck-pile to a dumping point, and are typically operated by a human who is sitting on-board the vehicle. Generally, an underground mine does not offer the best working environment for humans, and the job of an LHD operator can be characterised as Three D: Dangerous, Dirty and Dull. Tele-operated LHD vehicles are sometimes used in an attempt to remove the need of an on-board operator. However, tele-operation typically leads to reduced productivity and increased maintenance costs. The current trend is therefore toward fully autonomous, driver-less navigation systems.

    In this thesis, we present our approach to develop a reactive navigation system for operating an autonomous LHD vehicle in underground mines. The suggested system uses a coarse topological map for localisation, and a fuzzy behaviour-based approach for navigation. In our work, we have extended an existing framework for autonomous robot navigation and we have designed, developed and validated novel feature detection algorithms to enable reliable tunnel following and topological localisation. These algorithms operate on data from a laser scanner, and extract features such as tunnel center line and intersections. We claim, that the developed algorithms go beyond the state of the art because of their reduced computational cost and of their robustness with respect to sensor noise. To further increase the robustness of the topological localisation, we also propose the use of RFID technology by deploying passive RFID-tags at critical locations in the mine. To complement the description of our algorithms and system, we report on an initial implementation tested on ordinary research robots, and an extensive quantitative evaluation of the feature detection algorithms. This evaluation confirms the good performance of the algorithms, and their robustness to noise in the laser data. We also describe a few qualitative tests of the complete navigation system made in indoor environments using ordinary research robots. These tests indicate that the techniques developed in this thesis, originally intended for use in an underground mine, can also be used in other domains characterized by corridor-like features.

  • 7.
    Loutfi, Amy
    Örebro University, Department of Technology.
    Communicating perceptions: grounding symbols to artificial olfactory signals2003Licentiate thesis, monograph (Other academic)
  • 8.
    Lundh, Robert
    Örebro University, School of Science and Technology.
    Plan-Based Configuration of a Group of Robots2006Licentiate thesis, monograph (Other academic)
    Abstract [en]

    Imagine the following situation. You give your favorite robot, named Pippi, the task to fetch a parcel that just arrived at your front door. While pushing the parcel back to you, she must travel through a door opening. Unfortunately, the parcel she is pushing is blocking her camera, giving her a hard time to see the door to cross. If she cannot see the door, she cannot safely push the parcel through the door opening. What would you as a human do in a similar situation? Most probably you would ask someone for help, someone to guide you through the door, as we ask for help then we need to park our car in a tight parking spot. Why not let the robots do the same? Why not let robots help each other. Luckily for Pippi, there is another robot, named Emil, vacuum cleaning the floor in the same room. Since Emil can view both Pippi and the door at the same time, he can guide pippi through the door, enabling her to deliver the parcel to you.

    This work is about societies of autonomous robots in which robots can help each other by offering information-producing functionalities. A functional configuration is a way to allocate and connect functionalities among robots. In general, different configurations can be used to solve the same task, depending on the current situation. For the work on configurations, we have three steps. The first step is to formally define the idea of functional configuration. Second, to show how configurations can be automatically generated and executed. The third step is to address the problem of when and how to change a configuration in response to changing conditions. In this licenciate thesis we report initial work that focus on the two first steps: the third step is subject of future work. We propose a formal definition of functional configurations, and we propose an approach based on artificial intelligence (AI) planning techniques to automatically generate a preferred configuration for a given task, environment, and set of resources. To illustrate these ideas, we describe an experimental system where these are implemented, and show two example of it in which two robots mutually help each other to address tasks. In the first example they help each other to cross a door, and in the second example they carry a bar together.

  • 9.
    Lundh, Robert
    et al.
    Örebro University, Department of Technology.
    Karlsson, Lars
    Örebro University, Department of Technology.
    Saffiotti, Alessandro
    Örebro University, Department of Technology.
    An algorithm for generating configurations of groups of robots2007Report (Other academic)
    Abstract [en]

    This work is about the use of artificial intelligence (AI) planning techniques to automatically configure cooperation among robots. We consider groups of autonomous robots in which robots can help each other by offering information producing resources and functionalities. A configuration in this context, is a way to allocate and connect functionalities among robots. In general, different configurations can be used to solve the same task, depending on the current situation. Configuration generation is the problem of automatically generating a configuration for some specific purpose given a set of robotic devices possessing dfferent functionalities. In this paper, we consider an existing configuration planner both from a theoretical point of view (soundness, completeness, and optimality), and an empirical point of view (scalability). We also present a technique to improve the scalability of the configuration planner.

  • 10.
    Persson, Andreas
    Örebro University, School of Science and Technology.
    3D Scan-based Navigation using Multi-Level Surface Maps2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The field of research connected to mobile robot navigation is much broader than the scope of this thesis. Hence in this report, the navigation topic is narrowed down to primarily concerning mapping and scan matching techniques that were used to achieve the overall task of navigation nature. Where the work presented within this report is based on an existing robot platform with technique for providing 3D point-clouds, as result of 3D scanning, and functionality for planning for and following a path. In this thesis it is presented how a scan matching algorithm is used for securing the alignment between provided succession point-clouds. Since the computational time of nearest neighbour search is a commonly discussed aspect of scan matching, suggestions about techniques for decreasing the computational time are also presented within this report. With secured alignment, the challenge was within representing provided point-clouds by a map model. Provided point-clouds were of 3D character, thus a mapping technique is presented that provides rough 3D representations of the environment. A problem that arose with a 3D map representation was that given functionality for path planning required a 2D representation. This is addressed by translating the 3D map at a specific height level into a 2D map usable for path planning, where this report suggest a novel traversability analysis approach with the use of a tree structure.

     

  • 11.
    Rahayem, Mohamed
    Örebro University, Department of Technology.
    Planar segmentation for Geometric Reverse Engineering using data from a laser profile scanner mounted on an industrial robot2008Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Laser scanners in combination with devices for accurate orientation like Coordinate Measuring Machines (CMM) are often used in Geometric Reverse Engineering (GRE) to measure point data. The industrial robot as a device for orientation has relatively low accuracy but the advantage of being numerically controlled, fast, flexible, rather cheap and compatible with industrial environments. It is therefore of interest to investigate if it can be used in this application.

    This thesis will describe a measuring system consisting of a laser profile scanner mounted on an industrial robot with a turntable. It will also give an introduction to Geometric Reverse Engineering (GRE) and describe an automatic GRE process using this measuring system. The thesis also presents a detailed accuracy analysis supported by experiments that show how 2D profile data can be used to achieve a higher accuracy than the basic accuracy of the robot. The core topic of the thesis is the investigation of a new technique for planar segmentation. The new method is implemented in the GRE system and compared with an implementation of a more traditional method.

    Results from practical experiments show that the new method is much faster while equally accurate or better.

    List of papers
    1. Accuracy analysis of a 3D measurement system based on a laser profile scanner mounted on an industrial robot with a turntable
    Open this publication in new window or tab >>Accuracy analysis of a 3D measurement system based on a laser profile scanner mounted on an industrial robot with a turntable
    2007 (English)In: Proceedings of ETFA 12th IEEE conference on Emerging technologies and Factory Automation, 2007, p. 880-883Conference paper, Published paper (Other academic)
    Abstract [en]

    High accuracy 3D laser measurment systems are used in applications like inspection and reverse engineering (RE). With automatic RE in mind, we have designed and built a system that is based on a laser profile scanner mounted on a standard industrial robot with a turntable. This paper is concerned with the relatively complex accuracy issues of such a system. The different parts of the system are analyzed individually and a brief discussion of how they interact is given. Finally a detailed analysis of the scanner head along with experimental results is presented.

    National Category
    Engineering and Technology Computer Sciences
    Research subject
    Computer and Systems Science
    Identifiers
    urn:nbn:se:oru:diva-2983 (URN)10.1109/EFTA.2007.4416872 (DOI)978-1-4244-0825-2 (ISBN)
    Conference
    IEEE Conference on Emerging Technologies and Factory Automation, ETFA. 25-28 Sept. 2007
    Available from: 2008-06-11 Created: 2008-06-11 Last updated: 2018-01-13Bibliographically approved
    2. Geometric reverse engineering using a laser profile scanner mounted on an industrial robot
    Open this publication in new window or tab >>Geometric reverse engineering using a laser profile scanner mounted on an industrial robot
    2008 (English)In: Proceedings of the 6th international conference of DAAAM Baltic industrial engineering / [ed] Rein Kyttner, 2008, p. 147-152Conference paper, Published paper (Other academic)
    Abstract [en]

    Laser scanners in combination with accurate orientation devices are often used in Geometric Reverse Engineering (GRE) to measure point data. The industrial robot as a device for orientation has relatively low accuracy but the advantage of being numerically controlled, fast, and flexible and it is therefore of interest to investigate if it can be used in this application. We have built a measuring system based on a laser profile scanner mounted on an industrial robot. In this paper we present results from practical tests based on point data. We also show how data from laser profiles can be used to increase accuracy in some cases. Finally we propose a new method for plane segmentation using laser profiles.

    Keywords
    Geometric Reverse engineering, 3D measurement systems, laser scanning, segmentation, region growing
    National Category
    Engineering and Technology
    Research subject
    Mechanical Engineering
    Identifiers
    urn:nbn:se:oru:diva-2984 (URN)978-1-9985-59-783-5 (ISBN)
    Conference
    6th International conference of DAAAM Baltic industrial engineering, 24-26 April 2008, Tallinn, Estonia
    Available from: 2008-06-11 Created: 2008-06-11 Last updated: 2017-10-18Bibliographically approved
    3. Planar segmentation of data from a laser profile scanner mounted on an industrial robot
    Open this publication in new window or tab >>Planar segmentation of data from a laser profile scanner mounted on an industrial robot
    (English)Manuscript (Other academic)
    National Category
    Information Systems
    Research subject
    Computer and Systems Science
    Identifiers
    urn:nbn:se:oru:diva-2985 (URN)
    Available from: 2008-06-11 Created: 2008-06-11 Last updated: 2018-01-13Bibliographically approved
  • 12.
    Soron, Mikael
    Örebro University, Department of Technology.
    Prototyping a friction-stir welding robot2006Licentiate thesis, monograph (Other academic)
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