<p>Internet and mobile communications have had a profound effect on today’s society. New services are constantly being deployed, in which an increasing amount of personal data is being processed in return for personally tailored services. Further, the use of electronic surveillance is increasing. There is the risk that honest citizens will have their privacy invaded for “the greater good”. We argue that it is of uttermost importance to retain the individuals’ control over their personal spheres.</p><p>One approach for enhancing the users’ privacy is to deploy technical measures for safeguarding privacy, so-called Privacy-Enhancing Technologies (PETs). This thesis examines a set of PETs for enabling anonymous communication, so-called anonymous overlay networks,which eliminate the processing of personal data altogether by allowing the users act anonymously when communicating in a networked environment.</p><p>This thesis focuses mainly on mobile networks. These are of great interest because on the one hand they lay the groundwork for new innovative applications, but on the other hand they pose numerous novel challenges to privacy. This thesis describes the implementation</p><p>and performance evaluation of mCrowds – an anonymous overlay network for mobile Internet that enables anonymous browsing. It also describes the ongoing investigation on how to design anonymous overlay networks in order to make them suitable for mobile ad hoc</p><p>networks, a required building block for ambient intelligence.</p>

A new class of wireless sensor networks has recently appeared due to the pervasiness of cellular phones with embedded sensors, mobile Internet connectivity, and location technologies. This mobile wireless sensor network has the potential to address large-scale societal problems and improve the people's quality of life in a better, faster and less expensive fashion than current solutions based on static wireless sensor networks. Ubiquitous Sensing is the umbrella term used in this dissertation that encompasses location-based services, human-centric, and participatory sensing applications. At the same time, ubiquitous sensing applications are bringing a new series of challenging problems. This dissertation proposes and evaluates G-Sense, for Global-Sense, an architecture that integrates mobile and static wireless sensor networks, and addresses several new problems related to location-based services, participatory sensing, and human-centric sensing applications. G-Sense features the critical point algorithms, which are specific mechanisms to reduce the power consumption by continous sensing applications in cellular phones, and reduce the amount of data generated by these applications. As ubiquitous sensing applications have the potential to gather data from many users around the globe, G-Sense introduces a peer-to-peer system to interconnect sensing servers based on the locality of the data. Finally, this dissertation proposes and evaluates a multiobjective model and a hybrid evolutionary algorithm to address the efficient deployment of static wireless sensor nodes when monitoring critical areas of interest.

Η τεχνολογία Java, της οποίας η πρώτη επίσημη εμπορική εμφάνιση έγινε το 1995 από την Sun Microsystems, αποτελεί σήμερα μια ευρέως χρησιμοποιούμενη τεχνολογία που διαθέτει εξειδικευμένες πλατφόρμες για όλους τους τομείς ανάπτυξης εφαρμογών. Προσφέρει ένα ευέλικτο περιβάλλον ανάπτυξης στο οποίο ενσωματώνονται όλα τα πλεονεκτήματα της γλώσσας προγραμματισμού Java, ενώ παράλληλα παρέχει ένα δυναμικό μοντέλο ασφάλειας που συμπληρώνεται από την υποστήριξη των κορυφαίων πρωτοκόλλων διασύνδεσης. Ειδικότερα, η Java 2 Platform, Micro Edition (JavaMETM), είναι η πλατφόρμα που επεκτείνει τις δυνατότητες της τεχνολογίας Java στο χώρο των ενσωματωμένων συσκευών ευρείας κατανάλωσης, όπως τα κινητά τηλέφωνα και οι προσωπικοί ψηφιακοί βοηθοί (PDAs). Υποστηρίζοντας σημαντικά εργαλεία και τεχνολογίες, όπως το MIDP, η πλατφόρμα J2ME επιτρέπει την ανάπτυξη ευέλικτων και ασφαλών εφαρμογών, οι οποίες προσδίδουν στις συσκευές ευρείας κατανάλωσης έναν επικοινωνιακό και ψυχαγωγικό χαρακτήρα. Αντικείμενο της παρούσας διπλωματικής εργασίας αποτελεί η μελέτη των τεχνολογιών Java ME και ιδιαίτερα η μελέτη των χαρακτηριστικών της πλατφόρμας Web Services. Η εργασία αυτή συμπληρώνεται από την υλοποίηση μιας υπηρεσίας γνωριμιών με την χρήση ενός Location Based Server, η οποία απευθύνεται σε κινητά τηλέφωνα που υποστηρίζουν τη συγκεκριμένη τεχνολογία. Η υπηρεσία γνωριμιών πλαισιώνεται και από ένα πλήθος επιπλέον δυνατοτήτων εξεύρεσης των πλησιέστερων μουσείων, βενζινάδικων, σινεμά, εστιατορίων, καφετεριών και τέλος αστυνομικών τμημάτων. Η δομή της εργασίας έχει ως εξής: Στο πρώτο κεφάλαιο γίνεται μια σύντομη αναφορά στην τεχνολογία LBS. Στο δεύτερο κεφάλαιο αναλύονται τα χαρακτηριστικά της πλατφόρμας Web Services. Στο τρίτο κεφάλαιο περιγράφεται η αρχιτεκτονική του LBS, ενώ το τέταρτο κεφάλαιο αναφέρεται στην υλοποίηση του. Στο πέμπτο κεφάλαιο προσδιορίζεται ο τρόπος υλοποίησης της Java ME εφαρμογής που αναπτύχθηκε στα πλαίσια αυτής της εργασίας, ενώ στο έκτο και προτελευταίο κεφάλαιο παρουσιάζεται η βάση δεδομένων του LBS. / -

People describe and explore space with a strong emphasis on the visual senses, yet modelling the field of view has received little attention within the realm of Location Based Services (LBS), in part due to the lack of useful data. Advances in data capture, such as Light Detection and Ranging (LiDAR), provide new opportunities to build digital city models and expand the range of applications which use visibility analysis. This thesis capitalises on these advances with the development of a visibility model to support a number of innovative LBS functions in an urban region and particular focus is given to the visibility model‟s supporting role in the formation of referring expressions, the descriptive phrases used to identify objects in a scene, which are relevant when delivering spatial information to the user through a speech based interface. Speech interfaces are particularly useful to mobile users with restricted screen viewing opportunities, such as navigational support for motorists and a wider range of tasks including delivering information to urban pedestrians. As speech recognition accuracies improve so new interaction opportunities will allow users to relate to their surroundings and retrieve information on buildings in view through spoken descriptions. The papers presented in this thesis work towards this goal, by translating spatial information into a form which matches the user‟s perspective and can be delivered over a speech interface. The foundation is the development of a new visual exposure model for use in urban areas, able to calculate a number of metrics about Features of Interest (FOIs), including the façade area visible and the percentage on the skyline. The impact of urban vegetation as a semi-permeable visual barrier is also considered, and how visual exposure calculations may be adjusted to accommodate under canopy and through canopy views. The model may be used by pedestrian LBSs, or applied to vehicle navigation tasks to determine how much of a route ahead is in view for a car driver, identifying the sections with limited visibility or the best places for an overtaking manoeuvre. Delivering information via a speech interface requires FOI positions to be defined according to projective space relating to the user‟s viewpoint, rather than topological or metric space, and this is handled using a new egocentric model. Finally descriptions of the FOIs are considered, including a method to automatically collect façade colours by excluding foreground objects, and a model to determine the most appropriate description to direct the LBS user‟s attention to a FOI in view.

Η παρούσα διπλωματική εργασία αναφέρεται στην δημιουργία μιας εφαρμογής για κινητά τηλέφωνα, σε πλατφόρμα J2ME. Η εφαρμογή αυτή δίνει τη δυνατότητα στους χρήστες της, με τη βοήθεια υπηρεσιών βασισμένων στη θέση, να συγκρίνουν τις τιμές στις οποίες πωλούνται διάφορα βιβλία στα καταστήματα της περιοχής τους. Για την ανάπτυξη αυτής της εφαρμογής χρησιμοποιήθηκαν υπηρεσίες διαδικτύου που επιτρέπουν την επικοινωνία μεταξύ κινητών συσκευών και ενός κεντρικού εξυπηρετητή. Επίσης, αναπτύχθηκε μια βάση δεδομένων από την πλευρά του εξυπηρετητή, η οποία ενημερώνεται από τους ίδιους τους χρήστες. Για τον καθορισμό της γεωγραφικής θέσης του χρήστη χρησιμοποιείται το σύστημα GPS, ενώ για την παρουσίαση των αποτελεσμάτων χρησιμοποιήθηκε το Static Maps API. / The purpose of this diploma thesis is the development of an application designed for mobile phones, based on a J2ME platform. This application enables the users to use their phones in order to compare the prices of books among stores of a specific area. The development of this application includes a distributed system, which consists of two components: the client application, namely the users and the server application that contains a data base. This data base gets updated by the end users. The communication between the server and the client is based on Web Services. The users’ location is determined by the phone’s embedded GPS receiver. Finally, the Static Maps API is used for mapping the results.

Owing to the explosive growth of data driven by e-commerce, social media, and mobile apps, data outsourcing and integration have become two popular Internet services. These services involve one or more data owners (DOs), many requesting clients, and a service provider (SP). The DOs outsource/synchronize their data to the SP, and the SP will provide query services to the requesting clients on behalf of DOs. However, as a third-party server, the SP might alter (leave out or forge) the outsourced/integrated data and query results, intentionally or not. To address this trustworthy issue, the SP is expected to deliver their services in an authenticatable manner, so that the correctness of the service results can be verified by the clients. Unfortunately, existing work on query authentication cannot preserve the privacy of the data being queried. Furthermore, almost all previous studies assume only a single data source/owner, while data integration services usually combine data from multiple sources. In this dissertation, we take the first step to study the authentication of location-based queries with confidentiality and investigate authenticated online data integration services. Cost models, security analysis, and experimental results consistently show the effectiveness and robustness of our proposed schemes under various system settings and query workloads.

For the past recent years mobile developers and content providers have been aware of consumers’ engagement in online social networking. New opportunities are presented when using a mobile device as a medium for social interaction, also referred to as mobile social software. An ever growing effort aimed at various mobile design processes and applications have taken place. To achieve a widespread adoption of mobile social software amongst the main stream mobile consumer, several problem areas have to be taken into consideration, such as the technological possibilities and limitations of mobile phones, security issues regarding user privacy and the different aspects of consumers appeal for social media. This research looks into the overall situation of the current field of research and focuses on the interests in mobile social software amongst users. The study was geographically limited to Malmö, Sweden and focused on a population at the ages of 13-18.

Internet and mobile communications have had a profound effect on today’s society. New services are constantly being deployed, in which an increasing amount of personal data is being processed in return for personally tailored services. Further, the use of electronic surveillance is increasing. There is the risk that honest citizens will have their privacy invaded for “the greater good”. We argue that it is of uttermost importance to retain the individuals’ control over their personal spheres. One approach for enhancing the users’ privacy is to deploy technical measures for safeguarding privacy, so-called Privacy-Enhancing Technologies (PETs). This thesis examines a set of PETs for enabling anonymous communication, so-called anonymous overlay networks,which eliminate the processing of personal data altogether by allowing the users act anonymously when communicating in a networked environment. This thesis focuses mainly on mobile networks. These are of great interest because on the one hand they lay the groundwork for new innovative applications, but on the other hand they pose numerous novel challenges to privacy. This thesis describes the implementation and performance evaluation of mCrowds – an anonymous overlay network for mobile Internet that enables anonymous browsing. It also describes the ongoing investigation on how to design anonymous overlay networks in order to make them suitable for mobile ad hoc networks, a required building block for ambient intelligence.

Dagens smartphones är utrustade med GPS, vilket har blivit en användbar information för externa aktörer. Detta har skapat möjligheter för företag att kommunicera med sina användare, bland annat med hjälp av mobila kuponger. Det har tidigare funnits hinder för att utveckla mobila kuponger, som tekniska begränsningar, men nu är utmaningen att få förståelse för sina användare. Den här uppsatsen har undersökt hur användningen och uppfattningen av mobila kuponger ser ut idag, vilka faktorer som kan påverka användningen, samt hur dessa faktorer skulle kunna förbättras för att fler börjar använda tjänsten. Frågorna har besvarats med en enkätundersökning av 50 respondenter, samt en fokusgrupp med 6 deltagare. Resultatet visade att användningen av tjänsten inte är särskilt hög, men detta berodde främst på att man inte kände till att mobila kuponger fanns. Några viktiga faktorer som påverkade användningen var att man glömde bort att utnyttja kupongerna, en större ansträngning kändes mer pinsamt, samt att det kunde kränka integriteten. / The smartphones of today are provided with GPS’, which has created valuable opportunities for external actors. This in turn has created opportunities for companies to communicate with their consumers, by the use of mobile coupons for example. There have previously been technical obstacles for these kind of services, but now the challenge is to understand the consumer. This paper investigates the usage and the conceptions of mobile coupons at present, which elements that can affect the utilization and how these elements could be improved to spread the distribution of this service. The questions have been answered through a survey of 50 respondents and a focus group of 6 participants. The result proved that the usage of mobile coupons is not particularly high, however this was mainly due to bad awareness of the availability of the service. Some important factors affecting the utilization was forgetting to use the coupons, a bigger commitment was seen as awkward, or to intrude on the integrity.

Indoor positioning is an enabling technology primed to impact the indoor application space as Global Navigation Satellite Systems (GNSS) did for the outdoor space. Amongst the competing positioning technologies are methods of different mediums: light, radio frequency and ultra-wideband, ultrasonic, and imaging; methods of different modalities: received signal strength, angle-of-arrival, time-of-flight; and methods of different mathematics: trilateration, triangulation, machine learning, and signal processing. Light-based positioning compared to other positioning schemes exploits fixed-location directional luminaires placed regularly throughout a space as anchor points -- there is an efficiency argument for multi-purpose lighting and a cost-share argument for infrastructure-based positioning. Similar to the satellite infrastructure with GNSS, with anchor points and models for light propagation and construction, position is estimated based on received signals at active photodiode-equipped target devices. Received signal strength, a common first order attribute, alone is not noise resilient enough for centimeter-level 3D positioning. Methods using angle diversity produce better results particularly in 3D but with more complex hardware. For this dissertation, we exploit angle diversity and modulated optical sources in light-based positioning systems to estimate position to centimeter-level accuracy in 3D. We propose, analyze, and contribute two novel positioning schemes that use these concepts. One of the proposed schemes is a new hybrid 3D indoor positioning technique, Ray-Surface Positioning (RSP), which incorporates a narrow field-of-view (FOV) optical source (Ray) with wide diffuse optical sources (Surfaces) to position active devices in 3D. The second scheme, a Zone-based Positioning Service (ZPS), is a positioning scheme and architecture that incorporates an angle diverse narrow FOV optical source at the positioned device. This unique design decision allows the active device to position itself directly with respect to photovoltaic anchor points but also to position other devices in its FOV called transitive positioning. Along with these contributions, we also investigate several other related topics. Concisely, as part of the dissertation, we contribute (a) review of the state-of-the-art, (b) analysis for steering Lambertian sources, (c) method of creating angle diversity from a narrow FOV optical source, (d) novel positioning approaches in (1) RSP and (2) ZPS, (e) proof of concept prototypes for (1) RSP and (2) ZPS, and (f) architectures for indoor positioning applications.