Μη Οπτικός Πλοηγός Ναυτίλος: Σύστημα Πλοήγησης στον Παγκόσμιο Ιστό για Τυφλούς Χρήστες

In recent years the World Wide Web (Web) has evolved into an important source of information and the number of users who have access to it is increasing rapidly. This increase in the user population is accompanied by an increase of the population's diversity, with new accessibility and interaction requirements surfacing every day. The above necessitate the availability of Web navigation systems, which are capable of addressing the special abilities, requirements, skills and preferences of each individual user. In fact, such systems are a vital prerequisite for meeting the accessibility and interaction requirements of people with special needs, and especially of blind users, who represent a significant proportion of the potential user population. The existing Web navigation systems (or Web browsers, as they are commonly referred to) exhibit important shortcomings with respect to addressing the interaction needs of blind users. This, in turn, renders access to the Web by blind people a task that ranges from problematic to impossible. This thesis presents the non-visual Nautilus Web browser, which has been specifically developed to address the accessibility and interaction requirements of blind users on the Web. The non-visual Nautilus browser aims to cover accessibility gaps present in existing browsers, as well as to provide new interaction facilities, that will facilitate and enhance the interaction of blind users with Web content. Specifically, the non-visual Nautilus browser supports a multitude of input and output devices, and supports new software technologies in order to ensure access to all the interaction and presentation elements supported by the HTML 4.01 specification. Some of the advantages of the non-visual Nautilus browser in comparison to other Web browsers for blind people, are: its non-visual user interface, designed specifically for use by blind people; the provision of alternative views of an HTML document (e.g. separate presentation of document links, text-only presentation). Finally, the non-visual Nautilus browser supports a mode of operation indented for use at Public Information Kiosks. In this operation mode, the browser supports the basic navigation and interaction tasks of blind users over locally stored hypertexts, while the user interface is substantially simplified to facilitate ease of learning and usability, even for occasional users.Τα τελευταία χρόνια ο Παγκόσμιος Ιστός έχει εξελιχθεί σε μια σημαντική πηγή πληροφορίας και ο αριθμός των χρηστών που έχουν πρόσβαση σε αυτόν αυξάνεται με αλματώδεις ρυθμούς. Η αύξηση του πληθυσμού των χρηστών συνοδεύεται από αύξηση της ποικιλομορφίας του, με διαφορετικές απαιτήσεις πρόσβασης και αλληλεπίδρασης. Τα παραπάνω καθιστούν απαραίτητη την ύπαρξη συστημάτων πλοήγησης στον Παγκόσμιο Ιστό, τα οποία να ανταποκρίνονται στις ιδιαίτερες ικανότητες, απαιτήσεις, ανάγκες και προτιμήσεις του κάθε χρήστη. Η ύπαρξη τέτοιων συστημάτων είναι βασικό προαπαιτούμενο για την εξυπηρέτηση των απαιτήσεων πρόσβασης και αλληλεπίδρασης των ατόμων με ειδικές ανάγκες, και ειδικότερα των τυφλών χρηστών, που αποτελούν ένα σημαντικό ποσοστό του πληθυσμού. Τα υπάρχοντα συστήματα πλοήγησης στον Παγκόσμιο Ιστό παρουσιάζουν σημαντικές ελλείψεις στην κάλυψη των αναγκών αλληλεπίδρασης τυφλών χρηστών, γεγονός που καθιστά την πρόσβαση των τελευταίων στον Παγκόσμιο Ιστό από προβληματική έως αδύνατη. Στην παρούσα εργασία παρουσιάζεται ο μη οπτικός πλοηγός Ναυτίλος, ο οποίος έχει ως στόχο την εξυπηρέτηση των απαιτήσεων πρόσβασης και αλληλεπίδρασης των τυφλών χρηστών στον Παγκόσμιο Ιστό. Ο μη οπτικός πλοηγός Ναυτίλος έχει υλοποιηθεί με σκοπό την κάλυψη των κενών που παρουσιάζουν παρόμοια συστήματα πλοήγησης, και την παροχή νέων σημαντικών διευκολύνσεων στους τυφλούς χρήστες για την πλοήγησή τους στον Παγκόσμιο Ιστό. Συγκεκριμένα, υποστηρίζονται πολλαπλές συσκευές εισόδου και εξόδου, ενώ χρησιμοποιούνται νέες τεχνολογίες λογισμικού προκειμένου να παρέχεται πρόσβαση σε όλα τα αντικείμενα που υποστηρίζονται από τη γλώσσα περιγραφής υπερκειμένων HTML 4.01. Στα σημαντικά πλεονεκτήματα του μη οπτικού πλοηγού Ναυτίλου έναντι άλλων πλοηγών περιλαμβάνονται: η ειδικά σχεδιασμένη μη οπτική διεπαφή του, η παροχή εναλλακτικών θεάσεων παρουσίασης ενός εγγράφου (π.χ. παρουσίαση μόνο συνδέσμων, παρουσίαση μόνο κειμένου), καθώς και η υποστήριξη νέων μη-οπτικών μεθόδων αλληλεπίδρασης. Τέλος, ο μη οπτικός πλοηγός Ναυτίλος υποστηρίζει ένα ρυθμό λειτουργίας ειδικά σχεδιασμένο για χρήση σε Δημόσια Σημεία Πληροφόρησης (Information Kiosks). Σε αυτό το ρυθμό υποστηρίζονται οι βασικές λειτουργίες πλοήγησης και ανάγνωσης τοπικά αποθηκευμένων υπερκειμένων για τυφλούς χρήστες, ενώ η διεπαφή περιορίζεται δραστικά ώστε να είναι εύχρηστη από οποιονδήποτε περιστασιακό χρήστη του συστήματος

A digital platform for cross-sector collaborative value networks in the circular economy

In recent years there has been a growing interest in Circular Economy (CE), which promises to reduce waste and improve sustainability. The promise of CE is to change the conventional "take-make-dispose"that causes massive waste flows based on the integration of demanufacturing and remanufacturing processes within value chains. This integration requires breaking the "silos"of the circular chain to establish new collaborative and sustainable value networks. The paper introduces a novel digital platform for the CE, which is currently under development in the H2020 DigiPrime project. The platform is destined to facilitate seamless and trusted information exchange across circular actors, while offering a range of value-added services that enable manufacturers, remanufactures, recyclers and other actors to gain insights in the status of recycling and waste management processes. The latter facilitates the implementation of zero waste processes, along with the assessment of the performance of the circular chain. The paper introduces the architecture of the digital platform, along with its data modelling, exchange and data traceability mechanisms. It also presents a CE use case used to validate the platform

TURBOCHARGER UNSTABLE OPERATION DIAGNOSIS USING VIBROACOUSTIC MEASUREMENTS

ABSTRACT The possibility to detect unstable operating condition (stall or surge) of an automotive turbocharger using vibration or acoustic measurements is studied. An experimental study is performed, in order to acquire and analyze test data, to find out whether vibration or acoustic measurements can be correlated to aerothermodynamic operating condition. An instrumentation set allowing the definition of the operating point on the map of the compressor of the turbocharger is used. Hot wires the compressor inlet serve as flow condition indicators and provide a clear indicator of the presence or not of instabilities, such as rotating stall or surge. Accelerometers are mounted on the casing and microphones are placed in the vicinity of the compressor casing, to measure vibration and sound emission. Data covering an extensive range of the compressor performance map have been collected and analyzed. Signal features from the different measuring instruments are discussed. Using such features, a bi-parametric criterion is established for determination of whether the compressor operates in the stable part of its performance characteristic or in the presence of unstable operation phenomena (rotating stall, surge).The possibility of generalizing the validity of observations is supported, by presenting results from testing a second turbocharger, which is shown to exhibit similar behavior

OpenIoT: open source internet-of-things in the cloud

Despite the proliferation of Internet-of-Things (IoT) platforms for building and deploying IoT applications in the cloud, there is still no easy way to integrate heterogeneous geographically and administratively dispersed sensors and IoT services in a semantically interoperable fashion. In this paper we provide an overview of the OpenIoT project, which has developed and provided a first-of-kind open source IoT platform enabling the semantic interoperability of IoT services in the cloud. At the heart of OpenIoT lies the W3C Semantic Sensor Networks (SSN) ontology, which provides a common standards-based model for representing physical and virtual sensors. OpenIoT includes also sensor middleware that eases the collection of data from virtually any sensor, while at the same time ensuring their proper semantic annotation. Furthermore, it offers a wide range of visual tools that enable the development and deployment of IoT applications with almost zero programming. Another key feature of OpenIoT is its ability to handle mobile sensors, thereby enabling the emerging wave of mobile crowd sensing applications. OpenIoT is currently supported by an active community of IoT researchers, while being extensively used for the development of IoT applications in areas where semantic interoperability is a major concern