DEVELOPING AN UNDERSTANDING OF DIGITAL INTELLIGENCE AS A PREREQUISITE OF DIGITAL COMPETENCE

Although the interest of academics and practitioners is focused on concepts, such as digital competence, literacy, and skills, digital intelligence has its own distinct importance. Whilst the former concepts are related to knowledge and learning outcomes, digital intelligence is about the new way of thinking (particularly visible to young people) that is developing in the continuously expanding digital environment. Understanding and further investigating digital intelligence will help to establish better and more appropriate, for the demands of the digital era, frameworks of digital competence. This study proposes that measuring digital intelligence should comprise computational thinking tests, as well as tests that could be used to assess digital use and behaviour. In the context of that, a number of students at senior high schools of the Regional Unit of Thessaloniki, Greece, were tested regarding their computational thinking and their digital use and behaviour. The most interesting results are: (i) the average score of students increases as the level of education of their parents increases, and (ii) there is a statistically significant positive relationship of the students’ aggregate performance between computational thinking and digital use & behaviour, implying that they are correctly considered components of the construct of digital intelligence

Analyzing M-Service Quality Dimensions Using Multivariate Statistical Techniques

This paper continues previous work of the authors concerning the identification and statistical analysis of the quality dimensions in mobile services (m-services). In this work, the structure of mservice quality into dimensions and criteria, which these dimensions are further analyzed into, is examined and grounded through an empirical analysis. The use of multivariate statistical techniques is decomposed into two stages: in the first stage, Factor Analysis in order to explore the relationship between the examined items (quality criteria) and the constructs (dimensions) proposed through the study of the relevant literature. In the second stage, Cluster Analysis and Principal Component Analysis are employed in order to explore intra-construct relationships. The contribution of this paper lies on the fact that a mix of multivariate statistical techniques is all integrated in a single framework, so that information about the structure of m-service quality criteria and constructs is obtained. The findings of the study confirm the theoretical background and provide valuable managerial insights

Estimation of computer waste quantities using forecasting techniques

Technology changes rapidly over years providing continuously more options for computer alternatives and making life easier for economic, intra-relation or any other transactions. However, the introduction of new technology “pushes” old Information and Communication Technology (ICT) products to non-use. E-waste is defined as the quantities of ICT products which are not in use and is bivariate function of the sold quantities, and the probability that specific computers quantity will be regarded as obsolete. In this paper, an e-waste generation model is presented, which is applied to the following regions: Western and Eastern Europe, Asia/Pacific, Japan/Australia/New Zealand, North and South America. Furthermore, cumulative computer sales were retrieved for selected countries of the regions so as to compute obsolete computer quantities. In order to provide robust results for the forecasted quantities, a selection of forecasting models, namely (i) Bass, (ii) Gompertz, (iii) Logistic, (iv) Trend model, (v) Level model, (vi) AutoRegressive Moving Average (ARMA), and (vii) Exponential Smoothing were applied, depicting for each country that model which would provide better results in terms of minimum error indices (Mean Absolute Error and Mean Square Error) for the in-sample estimation. As new technology does not diffuse in all the regions of the world with the same speed due to different socio-economic factors, the lifespan distribution, which provides the probability of a certain quantity of computers to be considered as obsolete, is not adequately modeled in the literature. The time horizon for the forecasted quantities is 2014-2030, while the results show a very sharp increase in the USA and United Kingdom, due to the fact of decreasing computer lifespan and increasing sales

Investigating the factors that affect the time of maximum rejection rate of e-waste using survival analysis

This study aims at investigating the factors which influence positively or negatively electronic waste (e-waste) rejection rates. E-waste quantities have been calculated based on historical sales data worldwide and lifespan distribution. The methodology, which is adopted in this paper in order to estimate the effect that economic, cultural, and demographic factors have upon the time at which maximum e-waste rejection is achieved, is a Weibull parametric accelerated failure time model. Considering the event at which the maximum rejection of e-waste takes place as the dependent variable, it is assumed that it is a function of economic (GDP, GINI index, Internet users, exports/imports and prices), demographic (dependency ratio), and cultural covariates (literacy, masculinity, uncertainty avoidance). The variables are fed to the model after transformation into two major constructs derived from Factor Analysis: the first construct is Wealth (exports, imports, and GDP) and the second is Economic Disparity (size of households, literacy, Internet users, and GINI). The results demonstrate that the time of maximum e-waste rejection rate is prolonged by economic disparity and cultural variables (uncertainty avoidance), while wealth causes a shorter time of rejection rate. The proposed methodology is of great value, as its application could provide useful information in order to develop policies for optimal management of e-waste quantities

Privacy-preserving recommendations in context-aware mobile environments

© Emerald Publishing Limited. Purpose - This paper aims to address privacy concerns that arise from the use of mobile recommender systems when processing contextual information relating to the user. Mobile recommender systems aim to solve the information overload problem by recommending products or services to users of Web services on mobile devices, such as smartphones or tablets, at any given point in time and in any possible location. They use recommendation methods, such as collaborative filtering or content-based filtering and use aconsiderable amount of contextual information to provide relevant recommendations. However, because of privacy concerns, users are not willing to provide the required personal information that would allow their views to be recorded and make these systems usable. Design/methodology/approach - This work is focused on user privacy by providing a method for context privacy-preservation and privacy protection at user interface level. Thus, a set of algorithms that are part of the method has been designed with privacy protectionin mind, which isdone byusing realistic dummy parameter creation. Todemonstrate the applicability of the method, arelevant context-aware data set has been used to run performance and usability tests. Findings - The proposed method has been experimentally evaluated using performance and usability evaluation tests and is shown that with a small decrease in terms of performance, user privacy can be protected. Originality/value - This is a novel research paper that proposed a method for protecting the privacy of mobile recommender systems users when context parameters are used

A spatiotemporal Data Envelopment Analysis (S-T DEA) approach:the need to assess evolving units

One of the major challenges in measuring efficiency in terms of resources and outcomes is the assessment of the evolution of units over time. Although Data Envelopment Analysis (DEA) has been applied for time series datasets, DEA models, by construction, form the reference set for inefficient units (lambda values) based on their distance from the efficient frontier, that is, in a spatial manner. However, when dealing with temporal datasets, the proximity in time between units should also be taken into account, since it reflects the structural resemblance among time periods of a unit that evolves. In this paper, we propose a two-stage spatiotemporal DEA approach, which captures both the spatial and temporal dimension through a multi-objective programming model. In the first stage, DEA is solved iteratively extracting for each unit only previous DMUs as peers in its reference set. In the second stage, the lambda values derived from the first stage are fed to a Multiobjective Mixed Integer Linear Programming model, which filters peers in the reference set based on weights assigned to the spatial and temporal dimension. The approach is demonstrated on a real-world example drawn from software development

Interaction, structure and rheology of polymeric colloids and mixtures

The use of well defined macromolecular assemblies with tunable interactions represents the key for exploring the regime of soft-material behavior between hard spheres and polymer coils. Colloidal stars are ideal choices for such a formidable task and especially for shedding light on the formation and properties of dynamically arrested states. In this thesis, we demonstrate the rich variety of kinetic frustration phenomena that can be encountered with such ultrasoft particles. We address two specific examples in particular: the melting of star glass upon the addition of linear polymers and the reversible vitrification upon heating. In the first, star depletion appears to be the key to this effect and is related to the star–linear polymer size ratio. A detailed investigation indicates that with increasing the osmotic forces (due to the added polymer) these soft colloids first shrink and then form stable clusters. In the second, upon heating, concentrated solutions of colloidal stars in a solvent of intermediate quality (between θ and athermal) undergo a reversible glass like kinetic transition. This phenomenon can be attributed to the increase in the effective volume fraction of the stars with the temperature, which leads to the formation of clusters and causes the dynamic arrest of the solution. Due to the slow dynamics, unsteady and nonergodic behavior are typically present in this kind of transitions. To resolve these problems and obtain reliable information, we modified the classical Dynamic Light Scattering technique and developed a version of Multispeckle Autocorrelation Spectroscopy instrumentation. The application of this technique in the reversible vitrification phenomenon upon heating reveal that a logarithmic decay govern this glass-like transition.Η χρήση καλά χαρακτηρισμένων (από πλευράς χημείας) σύνθετων μακρομορίων με μεταβλητό δυναμικό αλληλεπίδρασης αποτελεί το κλειδί για την διερεύνηση της περιοχής χαλαρών υλικών με συμπεριφορά ανάμεσα σε σκληρές σφαίρες και πολυμερικά κουβάρια. Πολύκλωνα αστεροειδή πολυμερή αποτελούν ιδανική επιλογή συστημάτων για το σκοπό αυτό και ειδικά για την μελέτη σχηματισμού και ιδιοτήτων κινητικά παγιδευμένων καταστάσεων. Στην παρούσα εργασία παρουσιάσαμε ένα μεγάλο εύρος από φαινόμενα κινητικής παγίδευσης σε πυκνά διαλύματα των παραπάνω συστημάτων μέσω μεταβολής του χαλαρού απωστικού δυναμικού αλληλεπίδρασης τους. Συγκεκριμένα μελετήσαμε την ρευστοποίηση υάλου πολύκλωνων αστεροειδών πολυμερών με την προσθήκη γραμμικών αλυσίδων και την αντιστρεπτή μετάβαση στερεοποίησης πυκνών διαλυμάτων τους με την αύξηση της θερμοκρασίας. Στην πρώτη περίπτωση ο μηχανισμός αποκλεισμού φάνηκε να είναι το κλειδί για την κατανόηση του φαινομένου αυτού ο οποίος σχετίζεται με τον λόγο μεγέθους αστεριού- γραμμικής αλυσίδας. Λεπτομερή μελέτη έδειξε ότι η αύξηση των οσμωτικών δυνάμεων (μέσω της προσθήκης γραμμικών αλυσίδων) έχει σαν αποτέλεσμα την συρρίκνωση των αστεριών οδηγόντας τελικά σε μεγάλες συγκεντρώσεις γραμμικών αλυσίδων στον σχηματισμό συσσωματωμάτων αστεριών. Στην δεύτερη περίπτωση σε πυκνά διαλύματα πολύκλωνων αστεροειδών πολυμερών διεσπαρμένα σε διαλύτη ενδιάμεσης ποιότητας (όπου τα αστέρια μπορούν να διογκωθούν με την αύξηση της θερμοκρασίας) υπόκεινται σε μια αντιστρεπτή μετάβαση στερεοποίησης με την αύξηση της θερμοκρασίας. Αυτό το ενδιαφέρον φαινόμενο αποδώθηκε στο σχηματισμό συσσωματωμάτων λόγω αλληλοδιείσδυσης των διογκωμένων αστεριών με αποτέλεσμα την δυναμική παγίδευση τους. Λόγω της παρουσίας αργών δυναμικών διαδικασιών, στα φαινόμενα που μελετήσαμε, οδηγηθήκαμε στην τροποποίηση μιας από τις πειραματικές τεχνικές που χρησιμοποιήσαμε. Αυτή ήταν μια τροποποίηση της συμβατικής φασματοσκοπίας συσχέτισης φωτονίων (Δυναμική Σκέδαση Φωτός) χρησιμοποιώντας μια ψηφιακή CCD κάμερα σαν ανιχνευτή (Multispeckle Autocorrelation Spectroscopy). Δείξαμε ότι μέθοδος αυτή μας δίνει την δυνατότητα να μετρηθούν σωστά άκρως αργές διαδικασίες χαλάρωσης σε μή-εργοδικά ή εργοδικά συστήματα με αργές δυναμικές λόγω της στατιστικής υπεροχής της στους αργούς χρόνους (1-104sec) σε σχέση με τον συμβατικό τρόπο. Η εφαρμογή της για τη μελέτη του φαινόμενου της θερμοαντιστερπτής μετάβασης πήκτωσης (ή υάλου) αποκάλυψε την εμφάνιση μια αργής διαδικασίας χαλάρωσης, η οποία φθίνει λογαριθμικά και φαίνεται να ευθύνεται για την μακροσκοπική ακινητοποίηση του συστήματος