Wireless Sensor Networks (WSNs) continue to evolve as new applications emerge. In the recent past, WSNs were mostly single sink networks with a few number of homogeneous and static sensor nodes. Now, several applications require networks with multiple and moving sinks and targets as well as thousands of heterogeneous devices. However, the same constraints remain: sensor nodes continue to be very limited in resources, posing new challenges in the design of scalable and energy-efficient algorithms and communication protocols to support these new applications. This dissertation first addresses the problem of sink localization in large scale WSNs. A scalable and energy-efficient sink localization mechanism, called the Anchor Location Service (ALS), is introduced to support the use of location-based routing protocols. ALS avoids frequent and costly flooding procedures derived from the mobility of the sinks and targets, and utilizes face routing to guarantee the success of localization. The problem of topology control in heterogeneous environments is addressed next. A new topology control mechanism, the Residual Energy-Aware Dynamic (READ) algorithm, is devised to extend the lifetime of the network while maintaining connectivity. READ extends the lifetime of the network by assigning a more prominent role to more powerful devices. ALS and READ are evaluated and compared with other well-known protocols using analytical means and simulations. Results show that ALS provides a scalable sink location service and reduces the communication overhead in scenarios with multiple and moving sinks and targets. Results also show that READ increases both the network lifetime and the packet delivery rate.

The explosive adoption rate of cell phones over the past few years has increased the desire for advertising agencies to explore mobile as an advertising channel. Over 90% of Americans own a cell phone, which opens a new channel for advertising agencies to reach consumers. The traditional advertising channels include print, television, radio, and most recently, the Internet. This professional report explores the importance and utilization of mobile as an advertising channel in advertising agencies media plans for their clients. / text

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. / -

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Baigiamojo darbo tikslas – pateikti sprendimus, kaip naudoti geolokacinius socialinius tinklus, kaip reklamos priemonę, konkrečiai remiantis ,,Foursquare“ geolokacinio socialinio tinklo pavyzdžiu. Teorinėje darbo dalyje analizuojami teoriniai geolokacinių socialinių tinklų naudojimo aspektai: nagrinėjamos vietos nustatymu paremtos reklamos techninės galimybės, išsiaiškinami vietos nustatymu paremtos reklamos ir konkrečiai geolokacinių socialinių tinklų privalumai ir trūkumai. Taip pat nustatoma vartotojų segmentavimo svarba naudojant vietos nustatymu paremtus marketingo sprendimus, galiausiai išanalizuojamas geolokacinio socialinio tinklo ,,Foursquare“ veikimo principas, aptariamos galimybės verslui ir vartotojui, diskusiniai tinklo naudojimo klausimai. Analitinėje baigiamojo darbo dalyje apžvelgiami užsienio valstybių atliktų tyrimų rezultatai, pateikiami ir analizuojami anketinių apklausų apie geolokacinių socialinių tinklų naudojimo barjerus verslo ir vartotojų atžvilgiu duomenys, apibendrinami interviu su rinkodaros specialistu ir ryšio teikėjo atstovu rezultatai. Projektinėje darbo dalyje, remiantis tyrimo rezultatais, yra suformuluojami sprendimai, kaip naudoti geolokacinius socialinius tinklus verslas-verslui ir verslas-vartotojui lygmenyse. Modelio pavidalu pateikiami sprendimai komunikacijos priemonėms, reikalingoms ,,Foursquare“ nenaudojimą paversti naudojimu (ar bent jau nežinojimą paversti žinojimu). / The aim of this paper is to provide solutions how to use geolocation social networks as advertising. The solutions are provided on the basis of ,,Foursquare”. The first chapter of this paper focuses on the theoretical analysis of geolocation social networks use. At first, the location-based advertising technical issues are analyzed, the benefits are determined and the disadvantages of location-based advertising and in particular in geolocation social networks are pointed out. The paper also discusses the importance of segmentation in using geolocation social networks as an advertising tool. Finally, the geolocation social network ,,Foursquare” is analyzed to show the benefits for businesses and smart phone users. The second chapter of this paper analyzes statistics of the location-based advertising situation in foreign countries. In this chapter, the paper also discusses the results of surveys accomplished with marketers and smart phone users about difficulties of ,,Foursquare” use. Furthermore, the results of the interview with a network operator expert and a marketing specialist about barriers that cause slow adoption of geolocation social networks in Lithuania are analyzed. The third chapter focuses on possible solutions how to use geolocation social networks in business to business (B2B) and business to consumer (B2C) environments. Needed communication elements for ,,Foursquare“ use are provided in a model created by the author.

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.

Abstract Modern urban space, technological infrastructure, and sociability combine into a hybrid space that is the arena for urban pervasive games. Over the past two decades the changes in this game arena have been stealthy although substantial. Technological developments have helped to achieve true mobility of gaming devices, increased precision in localization, improved connectivity, and reduced orchestration required per player. Current pervasive location-based games can be played anytime anywhere. Subsequently, doors have been opened for a growing number of commercial games. These changes demand a new conceptualization of the urban game arena. This thesis focuses on playful appropriations of hybrid space. Hybrid space is urban space that entails ubiquitous technologies. Therefore, playful appropriations of hybrid space are always, to some extent, digital as well as urban. Prior research has identified two metaphors for urban pervasive games —true mobility and true sociability. This thesis proposes an additional metaphor, called synchronicity, for binding together different realities in pervasive games. They can be anything from mirror world like realistic virtual environments, such as 3D virtual representations of a city, to abstract realities, such as the backstory of the game, or the space identity of a certain location. While location awareness is an important binding factor between the virtual and physical worlds in pervasive gameplay, synchronizable elements can be anything from encouraged collocated gameplay to semantic similarities between the combined realities. This thesis is based on five game constructs that have been specifically designed and implemented as pervasive research games. Research data has been collected and analyzed with a mixed methods approach from field trials conducted in the wild. Constructive research is complemented with a literature review that maps the characteristics of current location-based mobile games and the game space. The main contribution of this thesis is the identification of the digital, abstract, and physical layers of reality in digital urban pervasive games. The second contribution is the identification and categorization of the synchronizable elements that bind these realities together. This thesis offers initial insights into translating this knowledge into the design of future pervasive games. / Tiivistelmä Urbaanitila on jatkuvassa muutoksessa, sillä se muotoutuu ja järjestyy uudelleen siellä kulkevien kaupunkilaisten kautta. Ubiikin teknologian, ihmisten kanssakäymisen ja modernin tilakäsityksen yhteisvaikutuksesta syntyy niin sanottu hybriditila, joka muodostaa peliareenan monille pervasiivisille peleille. Viime vuosikymmeninä tällä peliareenalla on tapahtunut vaivihkaisia mutta perustavaa laatua olevia muutoksia. Pelilaitteista on tullut aidosti mobiileja, ja ne kulkevat kaikkialla pelaajien mukana. Pelijärjestely vaatii vähemmän vaivaa pelaajaa kohden, paikannuksen tarkkuus on parantunut ja muutosten kautta myös kaupallisia pelejä on enemmän saatavilla. Nykyisiä pervasiivisia sijaintipohjaisia pelejä voi pelata milloin vain ja missä vain. Edellä mainittu kehitys edellyttää pervasiivisten pelien ja pelitilan uudelleen konseptualisointia. Väitöstyön aihe ei ole pelillisyys sellaisenaan, vaan “pelillisyys ja sen hyödyntäminen hybriditilassa”. Hybriditila on aina urbaani ja sisältää ubiikkia teknologiaa, minkä vuoksi pelit tässä tilassa ovat lähes poikkeuksetta myös digitaalisia. Aiempi tutkimus esittää, että saavutetut kehitysaskeleet voi niputtaa kahden metaforan alle. Nämä metaforat ovat: aito mobiilius sekä aito sosiaalisuus. Tämä väitöskirja esittää kolmannen, vielä määrittelemättömän tai saavuttamattoman metaforan näiden jatkoksi: synkronisuus. Synkronisoitavat piirteet tai elementit sitovat todellisuuksia yhteen pervasiivisessa pelitilassa. Tilassa olevat todellisuudet voivat olla realistisia pelimaailman kaltaisia virtuaalitiloja tai abstrakteja todellisuuksia, kuten pelitarinan muodostama todellisuus tai jonkin tietyn paikan tilaidentiteetti. Vaikka sijaintipohjaisuus on tärkeä todellisuuksia yhdistävä piirre, synkronisoitavat elementit voivat olla muutakin kuin sijaintikoordinaatteja. Pervasiiviset pelit nivoutuvat pelaajiensa päivittäiseen elämään, mikä tekee pelin kontekstista erottamattoman osan peliä. Tämä ominaisuus oikeuttaa ”in the wild” -menetelmien käytön tutkimuksessa, mikä tarkoittaa, että pelaamista ja pelejä tarkkaillaan luonnossa todellisessa ympäristössään. Tässä väitöstyössä käytetään konstruktioina varta vasten tätä tutkimusta ajatellen suunniteltuja ja toteutettuja pervasiivisia tutkimuspelejeä. Konstruktiivista tutkimusta tukee lisäksi teoreettinen tutkimusosio, joka koostuu kirjallisuuskatsaukseen pohjautuvasta nykyisten sijaintipohjaisten pelien ja pelitilan kategorisoinnista. Pervasiiviset pelit nivoutuvat pelaajiensa päivittäiseen elämään, mikä tekee pelin kontekstista erottamattoman osan peliä. Tämä ominaisuus oikeuttaa ”in the wild” -menetelmien käytön tutkimuksessa, mikä tarkoittaa, että pelaamista ja pelejä tarkkaillaan luonnossa todellisessa ympäristössään. Tässä väitöstyössä käytetään konstruktioina varta vasten tätä tutkimusta ajatellen suunniteltuja ja toteutettuja pervasiivisia tutkimuspelejeä. Konstruktiivista tutkimusta tukee lisäksi teoreettinen tutkimusosio, joka koostuu kirjallisuuskatsaukseen pohjautuvasta nykyisten sijaintipohjaisten pelien ja pelitilan kategorisoinnista.

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.