15 research outputs found

    CO2 and Radon Emissions as Precursors of Seismic Activity

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    AbstractThis paper reports a review on the relationship between seismic activity and the emissions of CO2 and radon. Direct, indirect and sampling methods are mainly employed to measure CO2 flux and concentration in seismic areas. The accumulation chamber technique is the mostly used in the literature. Radon gas emission in seismic areas can be considered as a short-term pre-seismic precursor. The study and the measurement of radon gas activity prior to earthquakes can be performed through active techniques, with the use of high-precision active monitors and through passive techniques with the use of passive detectors. Several investigators report models to explain the anomalous behavior of in-earth fluid gasses prior to earthquakes. Models are described and discussed

    Multivariate Analysis of Co-creation Activities in University Education

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    This paper investigates the viewpoints and perspectives of 179 undergraduate students engaged in a co-creation project regarding their anticipated progress, exploring, simultaneously, the affecting factors. The students attended the physics course in the Department of Industrial Design and Production Engineering at the University of West Attica, Greece. The investigation is implemented through a questionnaire that appraises the students' co-creation expectations in association with collected demographic data via twenty-two close-ended questions (Q1-Q22). Several statistical data sets are presented, including descriptive and correlation statistics and principal component and exploratory factor analyses. The majority of the replies are provided by male participants in their first year of study, with an average age of between 18 and 19. The correlation coefficient between the questions ranges from -.04 to.73, with the maximum occurring between the questions Q19 and Q20. Factor analysis justified by KMO (.862) and Bartlett’s sphericity (1749.843, p= .000) tests indicates five principal components within the following factors determining the undergraduate co-creation activities: responsible behaviour, feedback, helping, tolerance, and personal interaction. The above findings may contribute to the implementation of students’ co-creation as they are valuable tools for the design and pre-requisites for a successful implementation

    Modern methods for position control of systems : real-world and simulated application to a time variant pneumatic actuator

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    The Ph.D. programme arose naturally from the fundamental questions remaining after completing MPhil research at UWR in a very similar subject area. which was in achieving effective proportional position control of a linear pneumatic actuator. There are many challenging reasons for using pneumatic systems for control in certain important potential application areas, i.e., their numerous and multiple applications in modern industry due to their extensive beneficial characteristics. The still-unsolved problem of robust long-term proportional control of pneumatic actuators keeps the continuous research interest of engineers high. It is believed that when the operation time increases, so does the temperature inside the cylinder body.Any increase in temperature affects the system performance. For example, one effect is that the piston rubber expands and the contact area becomes greater; hence the frictional forces are affected. The rubber seal, which is between the piston and the cylinder body, also deforms according to air pressure increase. These long-term effects were the major cause of the problems that existed during all of the author's MPhil experimentation, using any kind of control method; the result was that frequent retuning of the controller could not be avoided.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Predictive Maintenance Using Machine Learning and Data Mining: A Pioneer Method Implemented to Greek Railways

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    In every business, the production of knowledge, coming from the process of effective information, is recognized as a strategic asset and source of competitive advantage. In the field of railways, a vast amount of data are produced, which is necessary to be assessed, deployed in an optimum way, and used as a mechanism, which will lead to making the right decisions, aiming at saving resources and maintain the fundamental principle of the railways which is the passengers’ safety. This paper uses stored-inactive data from a Greek railway company, and uses the method of data mining and applies machine learning techniques to create strategic decision support and draw up a risk and control plan for trains. We make an effort to apply Machine Learning open source software (Weka) to the obsolete procedures of maintenance of the rolling stock of the company (hand-written work orders from the supervisors to the technicians, dealing with the dysfunctions of a train unit by experience, the lack of planning and coding of the malfunctions and the maintenance schedule). Using the J48 and M5P algorithms from the Weka software, data are recorded, processed, and analyzed that can help monitor or discover, with great accuracy, the prevention of possible damage or stresses, without the addition of new recording devices—monitoring on trains, with the aim of predicting the diagnosis of the train fleet. The innovative method is capable of being used as a tool for the optimization of the management’s performance of the trains to provide the appropriate information for the implementation of planning and the technical ability of the trains in order to achieve the greatest target of importance for the railways, which is the passengers’ safety

    A Novel, Modular Robot for Educational Robotics Developed Using Action Research Evaluated on Technology Acceptance Model

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    This research evaluates a novel, modular, open-source, and low-cost educational robotic platform in Educational Robotics and STEM Education. It is the sequel of an action research cycle on which the development of this robot is based. The impetus for the need to develop this came from the evaluation of qualitative and quantitative research data collected during an educational robotics event with significant participation of students in Athens, which showed an intense interest in students in participating in educational robotics activities, but—at the same time—recorded their low involvement due to the high cost of educational robots and robotic platforms. Based on the research’s findings, this robot was designed to suit the whole educational community; its specifications came from its members’ needs and the processing and analysis of qualitative and quantitative data. This paper presents an evaluation of the robot using the Technology Acceptance Model. The robot was exposed to 116 undergraduate students attending a pedagogical university department to evaluate its handling according to the model’s factors. Research results were promising and showed a high degree of acceptance of the robot by these students and future teachers, providing the impetus for further research

    A Novel, Modular Robot for Educational Robotics Developed Using Action Research Evaluated on Technology Acceptance Model

    No full text
    This research evaluates a novel, modular, open-source, and low-cost educational robotic platform in Educational Robotics and STEM Education. It is the sequel of an action research cycle on which the development of this robot is based. The impetus for the need to develop this came from the evaluation of qualitative and quantitative research data collected during an educational robotics event with significant participation of students in Athens, which showed an intense interest in students in participating in educational robotics activities, but—at the same time—recorded their low involvement due to the high cost of educational robots and robotic platforms. Based on the research’s findings, this robot was designed to suit the whole educational community; its specifications came from its members’ needs and the processing and analysis of qualitative and quantitative data. This paper presents an evaluation of the robot using the Technology Acceptance Model. The robot was exposed to 116 undergraduate students attending a pedagogical university department to evaluate its handling according to the model’s factors. Research results were promising and showed a high degree of acceptance of the robot by these students and future teachers, providing the impetus for further research

    A Comparative Study of Control Methods for a Robotic Manipulator with Six DOF in Simulation

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    In this paper a comparative study of the classical control methods for the testing of a mathematical model, which controls six actuators of a six degrees of freedom robotic arm with a single controller, is illustrated, aiming to the constructive simplification of the system. In more detail, a mathematical model of the system is designed which simulates all mechanical parts, including 5-way directional pneumatic valve, the pneumatic actuators/pistons and the mathematical model of the controller. The purpose of the above is the tuning of a Single Input, Multiple Output (SIMO) controller which will direct the motion of the six pneumatic pistons. The thorough analysis of the implementation of the pneumatic system in Matlab/Simulink environment is followed by experimentation and results using Proportional (P), Proportional-Integral (PI), Proportional-Derivative (PD) and Proportional-Integral-Derivative (PID) controllers. The simulation results show the advantages of the above classical control methods on the robotic human arm which imitating human motion and made by a well-known company in the field of pneumatic automation

    A Comparative Study of Control Methods for a Robotic Manipulator with Six DOF in Simulation

    No full text
    In this paper a comparative study of the classical control methods for the testing of a mathematical model, which controls six actuators of a six degrees of freedom robotic arm with a single controller, is illustrated, aiming to the constructive simplification of the system. In more detail, a mathematical model of the system is designed which simulates all mechanical parts, including 5-way directional pneumatic valve, the pneumatic actuators/pistons and the mathematical model of the controller. The purpose of the above is the tuning of a Single Input, Multiple Output (SIMO) controller which will direct the motion of the six pneumatic pistons. The thorough analysis of the implementation of the pneumatic system in Matlab/Simulink environment is followed by experimentation and results using Proportional (P), Proportional-Integral (PI), Proportional-Derivative (PD) and Proportional-Integral-Derivative (PID) controllers. The simulation results show the advantages of the above classical control methods on the robotic human arm which imitating human motion and made by a well-known company in the field of pneumatic automation
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