Μεταπτυχιακές Διατριβές

Μόνιμο URI για αυτήν τη συλλογήhttps://dspace.library.tuc.gr/handle/123456789/42

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Πλοήγηση Μεταπτυχιακές Διατριβές ανά Συγγραφέα "Koutroulis Eftychios"

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  • Δεν υπάρχει διαθέσιμη μικρογραφία
    Δημοσίευση
    Design optimization of an electric energy production system for power supplying the nodes of wireless sensor networks
    (Technical University of Crete, 2015) Mandourarakis Ioannis; Μανδουραρακης Ιωαννης; Koutroulis Eftychios; Κουτρουλης Ευτυχιος; Kalaitzakis Kostas; Καλαϊτζακης Κωστας; Stavrakakis Georgios; Σταυρακακης Γεωργιος
    The widespread utilization of the Wireless Sensor Networks (WSNs) that are power supplied by Renewable Energy Sources (RES) is now leading scientific research towards the development of innovative sizing optimization techniques and configurations that aim in the service of multi-criteria objectives of economical and/or technical nature. The most frequently used ones have to do with the minimization of the overall cost and the maximization of the overall system efficiency, in terms of energy redundancy and operational reliability. Sizing optimization techniques are being introduced, where there is a tradeoff amongst similar to the aforementioned criteria that often contradict to each other (e.g. reliability is improved when economical cost or energy redundancy are increased). In this thesis, two complementary design optimization methods (a circuit level and a system level study) are presented for deriving the optimal configuration of the RES based energy production system of a WSN node, such that its total lifetime cost is minimized, while simultaneously guaranteeing that the data acquisition equipment is uninterruptedly power supplied during the entire year. The experimental results verify that, by applying the design variables as they were derived by the proposed optimization techniques at both the circuit and the system level, RES-based power-supply structures with a lower lifetime cost and higher power-processing efficiency are derived, compared to the non-optimally designed configurations. The design optimization and experimental results indicate that by using the proposed techniques, the total cost of the RES-based power supply system is reduced by 15.7 % and the DC DC converter efficiency is increased by 5.5 % compared to the corresponding results obtained by non-optimized power-supply structures.
  • Δεν υπάρχει διαθέσιμη μικρογραφία
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    Self-powered plant sensor for scatter radio
    (Technical University of Crete, 2015) Konstantopoulos Christos; Κωνσταντοπουλος Χρηστος; Koutroulis Eftychios; Κουτρουλης Ευτυχιος; Bletsas Aggelos; Μπλετσας Αγγελος; Deligiannakis Antonios; Δεληγιαννακης Αντωνιος
    In agriculture applications (e.g. greenhouses, vineyards etc.) it is required to automatically gather information about environmental variables such as soil and air humidity, as well as temperature in the vicinity of plants within the same field, with low-cost and high-scalability. Thus, sensor networks that are extending over a broad area and gather environmental data for microclimate monitoring, are indispensable for the application of optimal crop management techniques. The field of plant electro-physiology investigates the correlation of environmental variables with the electrical signals that are produced by diverse types of plants. Existing research in measurement of electrical signals generated by plants has been conducted using high-cost equipment, such as laboratory multi-meters and data-loggers, in order to perform the signal-conditioning and data acquisition operations required. This thesis introduces for first time in the existing research literature a novel low cost and self-powered sensor node that belongs to a large-scale scatter radio network and simultaneously is powered in a parasitic way to the plants, as well as is able to acquire and transmit these types of signals from each plant. Furthermore, in the context of this thesis, several experimental prototypes of the proposed node were developed, as well as used to gather measurements of electrical signals that are generated from multiple Avocado plants. The experimental results demonstrate the successful operation of the proposed WSN node, as well as indicate the correlation of plants signals with solar irradiation and plant irrigation events. Thus, the proposed system can be employed in precision agriculture applications for automated irrigation scheduling, control of the plant ambient conditions etc. based on data derived directly by the plants.