Optimization of the open-source hardware architectures' hardware robustness for the development and the implementation of wireless sensors networks’ nodes in the domain of agriculture

This doctoral thesis aims firstly to study the existing architectures for wireless sensors networks nodes’ hardware design and to identify their limitations, constraints and difficulties, and secondly to propose and establish of a novel architecture that can combine the advantages of existing architectures and ensure the elimination of any limitation and constraints in order to design hardware for nodes deployed in real-world application s in the harsh environment of agriculture. The methodology to meet the aforementioned aims includes: first the implementation of specific nodes’ hardware design case studies based on: i) the Typical Architecture, ii) the End-Systems Architectures, iii) the Commercial-of-the-Shelf Architectures, and iv) the Open-Source Hardware Architectures in order to identify particular issues per existing architecture; and second, the establishment of a new architecture for hardware design that can ensure the elimination of any issue such as those imposed by the existing architectures and that it can provide the advantages of End-Systems architectures with the benefits of Open-Source Hardware architectures. The results of the doctoral thesis include firstly the identification and presentation of specific constraints and limitations associated with each of the existing architectures of nodes’ hardware design. In particular, the traditional typical architecture appears to be insufficient in integrating new challenging technologies; End-Systems architectures whereas ensure focused solutions with optimized hardware of nodes they impose significant issues regarding scalability, expandability, reusability and high cost and longevity; Commercial-of-the-Shelf (COTS) Architectures on the other hand they found to be highly improper for deployments in real-world agricultural wireless sensors networks’ applications; while the Open-Source Hardware (OSH) architectures whereas they provide extensive degree of freedom in expandability, scalability, and reusability, they suffer from poor reliability, low energy efficiency, anarchy in expansion, and low robustness for operating in the harsh agricultural environment. Secondly, results include the proposition of a new architecture, namely the SensoTube. This architecture is based on the establishment of a conceptual abstraction of seven distinct functional layers with which any wireless sensors networks nodes hardware can ve studied, modeled, described, designed and implemented in a very comprehensive way. The SensoTube is described in detail. Specifically, its printed-circuit board reference model of implementation is given along with the introduction of novel mechanisms for signals and communications management, energy management, and management of the programming and debugging of microcontrollers of the nodes which allow for inter-layer services. Ultimately, the proposed architecture is evaluated and tested according particular design case studies.Η παρούσα διδακτορική διατριβή στοχεύει στην μελέτη των διαθέσιμων αρχιτεκτονικών σχεδιασμού υλικού κόμβων ασύρματων δικτύων αισθητήρων και στον εντοπισμό των περιορισμών και των δυσκολιών που αυτές επιβάλλουν και την πρόταση και την δημιουργία μιας νέας αρχιτεκτονικής η οποία θα ενσωματώνει όλα τα πλεονεκτήματα όλων των υπαρχουσών αρχιτεκτονικών και στην διευθέτηση όλων των αδυναμιών και των περιορισμών. Η μεθοδολογία για την επίτευξη των στόχων περιλαμβάνει την μελέτη του σχεδιασμού υλικού ασύρματων κόμβων βασισμένου σε: α) Τυπική Αρχιτεκτονική (Typical Architecture), β) Αρχιτεκτονικές Ειδικού Σκοπού (End-Systems Architectures), γ) Αρχιτεκτονικές Εμπορικά Διαθέσιμων Λύσεων Γενικής Χρήσης (Commercial-of-the-Shelf Architectures), και δ) στις Αρχιτεκτονικές Ανοικτής Πηγής (Open-Source Hardware Architectures). Τα προβλήματα, οι περιορισμοί και οι αδυναμίες κάθε μιας από τις προαναφερόμενες αρχιτεκτονικές σχεδιασμού υλικού ασύρματων κόμβων δικτύων αισθητήρων ανιχνεύονται μέσω μελετών περιπτώσεων σχεδιασμού Design Case Studies). Στην συνέχεια προτείνεται μια νέα αρχιτεκτονική η οποία θα εξαλείφει τα προβλήματα που επιβάλλουν οι υπάρχουσες αρχιτεκτονικές και θα δίνει έμφαση στα πλεονεκτήματα των αρχιτεκτονικών υλικού ανοικτής πηγής και ειδικού σκοπού. Τέλος, η προτεινόμενη αρχιτεκτονική εξετάζεται σε βάθος μέσω αντιπροσωπευτικών μελετών περιπτώσεων σχεδιασμού υλικού. Στα αποτελέσματα της διδακτορικής διατριβής συγκαταλέγονται: α) η πλήρης τεκμηρίωση των αδυναμιών, των περιορισμών και των προβλημάτων που επιβάλλουν οι εξεταζόμενες υπάρχουσες αρχιτεκτονικές σχεδιασμού υλικού κόμβων ασύρματων δικτύων αισθητήρων. Συγκεκριμένα, εντοπίστηκαν περιορισμοί και αδυναμίες που σχετίζονται με την διαχείριση ηλεκτρικών σημάτων, την διαχείριση πόρων επικοινωνίας, την διαχείριση ενέργειας, καθώς και το κόστος, την ευελιξία, την κλιμάκωση, την ανοικτότητα, την επεκτασιμότητα, την αξιοπιστία και την ευρωστία του υλικού των κόμβων. Επίσης, εμφανίστηκε πως είναι απαραίτητη η ύπαρξη μιας νέας αρχιτεκτονικής η οποία θα συνδυάζει την αξιοπιστία και την ευρωστία του αρχιτεκτονικών ειδικού σκοπού με την ευελιξία και την επεκτασιμότητα και επαναχρησιμοποίηση των αρχιτεκτονικών ανοικτής πηγής. β) η πρόταση και η δημιουργία μιας νέας αρχιτεκτονικής σχεδιασμού υλικού ασύρματων κόμβων δικτύων αισθητήρων, της αρχιτεκτονικής SensoTube. Η εν λόγω αρχιτεκτονική, στηρίζεται σε μια εννιολογική αφαίρεση επτά διακριτών επιπέδων λειτουργιών μέσω των οποίων οποιοδήποτε υλικό ασύρματου κόμβου δύναται να περιγραφεί, να μελετηθεί και να σχεδιαστεί. Επί προσθέτως, η προτεινόμενη αρχιτεκτονική SensoTube εισάγει την χρήση καινοτόμων μηχανισμών για την διαχείριση των σημάτων και των επικοινωνιών, τη διαχείριση του προγραμματισμού και της εκσφαλμάτωσης μικροελεγκτών, καθώς και της διαχείρισης της ενέργειας του ασύρματου κόμβου. Μέσω συγκεκριμένων μελετών περιπτώσεων σχεδιασμού αποδεικνύεται πως η προτεινόμενη αρχιτεκτονική SensoTube διασφαλίζει την κλιμάκωση, την ευελιξία, την επαναχρησιμοποίηση, τον επανακαθρορισμό και την επεκτασιμότητα που απαιτούνται στον σχεδιασμό και στην υλοποίηση εύρωστου υλικού ασύρματων κόμβων για το απαιτητικό περιβάλλον της Γεωργίας

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Wireless Sensor and Actuators Networks (WSANs) constitute one of the most challenging technologies with tremendous socio-economic impact for the next decade. Functionally and energy optimized hardware systems and development tools maybe is the most critical facet of this technology for the achievement of such prospects. Especially, in the area of agriculture, where the hostile operating environment comes to add to the general technological and technical issues, reliable and robust WSAN systems are mandatory. This paper focuses on the hardware design architectures of the WSANs for real-world agricultural applications. It presents the available alternatives in hardware design and identifies their difficulties and problems for real-life implementations. The paper introduces SensoTube, a new WSAN hardware architecture, which is proposed as a solution to the various existing design constraints of WSANs. The establishment of the proposed architecture is based, firstly on an abstraction approach in the functional requirements context, and secondly, on the standardization of the subsystems connectivity, in order to allow for an open, expandable, flexible, reconfigurable, energy optimized, reliable and robust hardware system. The SensoTube implementation reference model together with its encapsulation design and installation are analyzed and presented in details. Furthermore, as a proof of concept, certain use cases have been studied in order to demonstrate the benefits of migrating existing designs based on the available open-source hardware platforms to SensoTube architecture

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3D Printing and Implementation of Digital Twins: Current Trends and Limitations

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