In modern society, security has become an increasingly important subject, as technologyhas become an integrated part of everyday life. The security of a system can be tested withthe help of fuzzing, where incoming messages to the system are altered. In this thesis, afuzzer was developed targeting an E-UTRAN Node B (eNB) in the Long-Term Evolution(LTE) landscape. The eNB is current prototype and is from the company Ericsson. Thefuzzer is particularly designed for testing the Medium Access Control (MAC) layer of theeNB. The fuzzer uses a genetic method where all of the fuzzer’s flags (the R, F2, E, LCID, Fand L flags) are triggered during the fuzzing period. Depending on the output of the firstgeneration of fuzzed values, new values are generated either by choosing a value close tothe original value, or by choosing a value that belong to the same subgroup as the originalvalue. Four test cases are made, where first test case is the base line of the program and theother three test cases fuzzes the eNB, using different parts of the fuzzer. The results show that depending on which parts of the fuzzer are used, the connectionbecomes different. For test two and three, the connection became increasingly unstable andmore data was present in the connection. Test case four did not however deviate so muchfrom the baseline, if compared to test two and three.

In this thesis the structure and hydration of small organic and amphipilic compounds adsorbed at the air-liquid interface, have been studied using the nonlinear optical technique Vibrational Sum Frequency Spectroscopy (VSFS). The second order nature of the sum frequency process makes this technique particularly surface sensitive and very suitable for interfacial studies, as molecules at the surface can be distinguished even in the presence of a vast excess of the same molecules in the bulk. Particular emphasis was given to the surface water structure and how it is affected by the presence of small model compounds such as acetic acid and formic acid, and also non-ionic surfactants with sugar based and ethylene oxide based polar headgroups. Understanding the structure of water at these interfaces is of considerable fundamental importance, and here VSFS provided unique information. Upon addition of tiny amounts of these surface active compounds, the ordered surface structure of water was found to be significantly perturbed, as revealed by the changes observed in the characteristic spectroscopic signature of the dangling OH bond of water molecules, which vibrate free in air and are present in the top monolayer. Dramatic differences between the different compounds were also observed in the bonded OH region, providing a valuable insight into the hydration of polar groups at interfaces. Additionally, by employing different polarization combinations of the laser beams involved in the sum frequency process, information about the different water species present at the surface and their average orientation were extracted. In particular an unusual state of water was found with a preferred orientation in a non-donor configuration in close proximity to the hydrophobic region formed by the hydrocarbon tails of the surfactant molecules. The conformation and orientation of the different adsorbates were also characterized, targeting their specific vibrational frequencies. Noteworthy is the orientation of the fluorocarbon chain of ammonium perfluorononanoate (APFN), which in contrast to the hydrocarbon chains of the other surfactant molecules studied, remained constant over a wide range of surface densities. This behaviour was also observed for the anionic headgroup of sodium dodecyl sulphate (SDS). Other interesting findings were the formation of a cyclic dimer bilayer at the surface of concentrated aqueous solutions of acetic acid and the water structuring effect induced by poly(ethylene-oxide) headgroups, in spite of being themselves disordered at the air-liquid interface.

<p>In this thesis the structure and hydration of small organic and amphipilic compounds adsorbed at the air-liquid interface, have been studied using the nonlinear optical technique Vibrational Sum Frequency Spectroscopy (VSFS). The second order nature of the sum frequency process makes this technique particularly surface sensitive and very suitable for interfacial studies, as molecules at the surface can be distinguished even in the presence of a vast excess of the same molecules in the bulk. Particular emphasis was given to the surface water structure and how it is affected by the presence of small model compounds such as acetic acid and formic acid, and also non-ionic surfactants with sugar based and ethylene oxide based polar headgroups. Understanding the structure of water at these interfaces is of considerable fundamental importance, and here VSFS provided unique information. Upon addition of tiny amounts of these surface active compounds, the ordered surface structure of water was found to be significantly perturbed, as revealed by the changes observed in the characteristic spectroscopic signature of the dangling OH bond of water molecules, which vibrate free in air and are present in the top monolayer. Dramatic differences between the different compounds were also observed in the bonded OH region, providing a valuable insight into the hydration of polar groups at interfaces. Additionally, by employing different polarization combinations of the laser beams involved in the sum frequency process, information about the different water species present at the surface and their average orientation were extracted. In particular an unusual state of water was found with a preferred orientation in a non-donor configuration in close proximity to the hydrophobic region formed by the hydrocarbon tails of the surfactant molecules.</p><p>The conformation and orientation of the different adsorbates were also characterized, targeting their specific vibrational frequencies. Noteworthy is the orientation of the fluorocarbon chain of ammonium perfluorononanoate (APFN), which in contrast to the hydrocarbon chains of the other surfactant molecules studied, remained constant over a wide range of surface densities. This behaviour was also observed for the anionic headgroup of sodium dodecyl sulphate (SDS). Other interesting findings were the formation of a cyclic dimer bilayer at the surface of concentrated aqueous solutions of acetic acid and the water structuring effect induced by poly(ethylene-oxide) headgroups, in spite of being themselves disordered at the air-liquid interface.</p>

Depuis son invention en 1986, les microscopes à force atomique (AFM) ont été des puissants outils pour la caractérisation des matériaux et des propriétés des matériaux à l'échelle nanométrique. Cette thèse est entièrement dédiée à la mesure de l'interaction entre une sonde AFM et une surface avec une nouvelle technique AFM appelée Force Feedback Microscopy (FFM). La technique a été développée et utilisée pour l'étude d'échantillons biologiques. Le principe central de la technologie FFM est que la force totale moyenne appliquée à la pointe est égal à zéro. En conséquence, en présence d'une interaction pointe-échantillon, une force égale et contraire doit être appliquée à la pointe par une boucle de rétroaction. La force de réaction est ici appliquée à la pointe à travers le déplacement d'un petit élément piézoélectrique positionné à la base du levier AFM. La boucle de rétroaction permet d'éviter instabilités mécaniques tels que le saut au contact, permettant la mesure complète de la courbe d'interaction. En plus, il donne la possibilité de mesurer simultanément les parties élastique et inélastique de l'interaction. La technique a été appliquée à l'étude des interactions à l'interface solide/gaz, avec un intérêt particulier pour l'observation de la formation et de la rupture des ponts capillaires entre pointe et échantillon. Ensuite, on a focalisé notre attention aux interfaces solide/liquide. Dans ce contexte, courbes complètes de type DLVO sont caractérisées d'un point de vue élastique et dissipatif. Nous avons développé des nouveaux modes d'imagerie AFM pour l'étude des biomolécules. Images de phospholipides et de l'ADN à force constante ont été réalisées et certaines propriétés mécaniques comme le module de Young des échantillons ont été évaluées. En plus, nous avons réalisé une étude spectroscopique de l'élasticité et du coeffcient d'amortissement de l'interaction entre des cellules vivantes de type PC12 et une pointe AFM en nitrure de silicium. L'étude montre que le FFM est un instrument capable de mesurer l'interaction à des fréquences qui ne sont pas nécessairement liées aux résonances caractéristiques du levier. L'étude spectroscopique pourrait avoir dans le futur des applications importantes pour l'étude des biomolécules et des polymères.

Abstract The aim of this thesis is to propose an array of novel cooperative content delivery (CCD) methods and related incentive mechanisms for future fifth-generation (5G) and beyond networks. CCD using multiple air interfaces is a powerful solution to mitigate the problem of congestion in wireless networks, in which the available multiple air interfaces on smart devices are utilized intelligently to distribute data content among a group of users that are in the vicinity of one another. The requirements for higher capacity, reliability, and energy efficiency in the 5G networks have warranted the development of methods focusing on CCD. Moreover, critical to the efficiency of a CCD process are incentive mechanisms to induce cooperation among the mobile users engaged in CCD. The first part of the thesis studies an ideal condition of reliable and error-free distribution of content using cellular and short-range links. The main contribution is to introduce different device selection CCD methods that take into account only the link quality of the devices’ primary (cellular) interfaces. The proposed methods provide frequency carrier savings for the operator while allowing users to enjoy higher downlink rates. The second part of the thesis studies a more realistic CCD situation where users with low data rate wireless links can be a bottleneck in terms of CCD performance. The main contribution is to propose a novel device selection CCD method that considers the link quality of both primary (cellular) and secondary (short-range) interfaces of the devices. Additionally, a carrier aggregation-based incentive mechanism for the proposed method is introduced to address the challenge of selfish deviating users. The proposed mechanism maximizes individual and network payoffs, and is an equilibrium against unilateral selfish deviations. The third part of the thesis addresses the adverse selection problem in CCD scenarios. The operator is assumed to have incomplete information about the willingness of the users to participate in CCD. The main contribution is to introduce contract-based methods through which the operator could motivate users to reveal their true willingness towards participation. The proposed methods incentivize users according to their willingness and improve system performance in terms of the utility of the operator and the users. / Tiivistelmä Tämän väitöskirjan tavoitteena on kehittää menetelmiä yhteistyössä tapahtuvaan sisällön jakamiseen (cooperative content delivery, CCD) sekä siihen liittyviä kannustinmekanismeja viidennen sukupolven (5G) ja sen jälkeisille matkaviestinverkoille. CCD:n käyttö hyödyntämällä älylaitteessa olevia useita ilmarajapintoja on tehokas ratkaisu välttää langattomien verkkojen ruuhkautumista. CCD-menetelmissä laiteen ilmarajapintoja käytetään älykkäästi datan jakamiseen käyttäjäryhmälle, kun käyttäjät ovat lähellä toisiaan. 5G-verkkojen vaatimukset korkeammalle kapasiteetille, luotettavuudelle ja energiatehokkuudelle ovat motivoineet CCD-menetelmien kehitystyötä. Erityisen tärkeää CCD-menetelmien tehokkuudelle on kannustinmekanismien kehittäminen mahdollistamaan yhteistyö mobiilikäyttäjien välillä. Väitöskirjatyön ensimmäinen osuus käsittelee ideaalista tilannetta luotettavalle ja virheettömälle sisällön jakamiselle hyödyntämällä solukkoverkkoa ja lyhyen kantaman linkkejä. Tässä osuudessa päätuloksena on kehitetty käyttäjien valinnalle menetelmiä, jotka huomioivat linkin laadun solukkoverkon ilmarajapinnassa. Ehdotetut menetelmät tuovat operaattorille säästöjä taajuusresurssien käytön osalta ja käyttäjät saavuttavat korkeampia laskevan siirtotien datanopeuksia. Työn toinen osuus tutkii todenmukaisempaa CCD-tilannetta, jossa alhaisen datanopeuden linkkien käyttäjät voivat olla pullonkaula CCD:n suorituskyvylle. Päätulos tässä on uusi käyttäjien valintamenetelmä, joka ottaa huomioon linkkien laadun sekä solukkoverkossa että lyhyen kantaman linkeissä. Lisäksi esitellään eri taajuuksien yhdistämistä hyödyntävä kannustinmenetelmä, joka ottaa huomioon itsekkäiden käyttäjien aiheuttamat ongelmat. Ehdotettu mekanismi maksimoi yksittäisen käyttäjän ja verkon hyödyt ja saavuttaa tasapainotilan käyttäjien yksipuolista itsekkyyttä vastaan. Väitöskirjan kolmannessa osuudessa tutkitaan haitallisen valikoitumisen mahdollisuutta CCD:ssä. Operaattorilla oletetaan olevan epätäydellistä tietoa käyttäjien halukkuudesta osallistua yhteistyöhön CCD:ssä. Tämän osuuden päätulos on esitellä sopimuksiin perustuvia kannustinmenetelmiä, joiden avulla operaattori voi motivoida käyttäjiä paljastamaan heidän todellinen tahtotilansa osallistua yhteistyöhön. Ehdotetut menetelmä kannustavat käyttäjiä heidän todellisen tahtotilan perusteella ja parantavat järjestelmän suorituskykyä operaattorin ja käyttäjien saavuttamien hyötyjen osalta.

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