This work deals with roaming issues in the WiFi network. Takes options from a 802.11 standard view. Factory setting options for fast roaming from CISCO and MikroTik. It proposes to measure and test these networks.

Awareness of vehicles’ surrounding conditions is important in today’s intelligent transportation system. A wide range of effort has been put in to deploy Vehicular Communication (VC) systems to make driving conditions safer and more efficient. Vehicles are aware of their surroundings with the help of authenticated safety beacons in VC systems. Since vehicles act according to the information conveyed by such beacons, verification of beacons plays an important role in becoming aware of and predicting the status of the sender vehicle. The idea of implementing secure mechanisms to deal with a high rate of incoming beacons and processing them with high efficiency becomes a very important part of the whole VC network. The goal of this work was to implement a scheme that deals with a high rate of the incoming beacon, preserve non-repudiation of the accepted messages which contains information about the current and near-future status of the sender vehicle, and at the same time keep the computation overhead as low as possible. Along with this, maintaining user privacy from a legal point of view as well as from a technical perspective by implementing privacy-enhancing technologies. These objectives were achieved by the introduction of Timed Efficient Stream Loss-Tolerant Authentication (TESLA), periodic signature verification, and cooperative verification respectively. Four different scenarios were implemented and evaluated, starting and building upon the baseline approach. Each approach addressed the problems that were aimed at this work and results show improved scalability and efficiency with the introduction of TESLA, periodic signature verification, and cooperative verification. / Medvetenheten om fordons omgivande förhållanden är viktig i dagens intelligenta transportsystem. Ett stort antal ansträngningar har lagts ned för att distribuera VC system för att göra körförhållandena säkrare och effektivare. Fordon är medvetna om sin omgivning med hjälp av autentiserade säkerhetsfyrar i VC system. Eftersom fordon agerar enligt den information som förmedlas av sådana fyrar, spelar verifiering av fyrar en viktig roll för att bli medveten om och förutsäga avsändarfordonets status. Idén att implementera säkra mekanismer för att hantera en hög frekvens av inkommande fyrar och bearbeta dem med hög effektivitet blir en mycket viktig del av hela VC nätverket. Målet med detta arbete var att implementera ett schema som behandlar en hög hastighet för det inkommande fyren, bevara icke-förkastelse av de accepterade meddelandena som innehåller information om den aktuella och närmaste framtida statusen för avsändarfordonet och samtidigt håll beräkningen så låg som möjligt. Tillsammans med detta upprätthåller användarnas integritet ur juridisk synvinkel såväl som ur ett tekniskt perspektiv genom att implementera integritetsförbättrande teknik. Dessa mål uppnåddes genom införandet av TESLA, periodisk signatur verifiering respektive samarbets verifiering. Fyra olika scenarier implementerades och utvärderades med utgångspunkt från baslinjemetoden. Varje tillvägagångssätt tog upp de problem som riktades mot detta arbete och resultaten visar förbättrad skalbarhet och effektivitet med införandet av TESLA, periodisk signatur verifiering och samarbets verifiering.

In an IEEE802.15.4 beacon-enabled wireless personal area network (WPAN), the PAN coordinator can allocate slots using contention free-GTSs (guaranteed the time slots) for admitted devices. However, due to fixed slot size, the bandwidth waste problem may arise. Hence, reference [6] proposed the multi-beacon superframe structure (MBS) to overcome this problem. However, in [6], the structure of sub-beacon intervals in a superframe is non-adaptive. Therefore, this thesis proposes an enhanced multi-beacon superframe structure (EMBS). In EMBS, a PAN coordinator employs the greedy SBI-allocation algorithm to adjust a superframe structure according to the traffic demand of admitted devices such that a superframe can consist of a number of different types of sub-beacon intervals (SBIs). Simulation results reveal that a WPAN using EMBS can attain higher bandwidth utilization than a WPAN using 802.15.4 or MBS.

Diss.--Philosophische Fakultät I--Zürich--Universität Zürich, 1989/1990.

The thesis deal with possibility of localization of avalanche victims. Main focus is for RF avalanche beacons. The major objects of this thesis are design and construction of this device. A large part of thesis describes design of avalanche beacon and particular steps of realization. The design take into account the compatibility with commercial beacons. The paramters of designed device are verified by testing and measurement.

No description available.

The project aims to elevate Halmstad’s historical and contemporary culture. Today, the artistic practice is conducted in separate and closed of cultural clusters. By givning the city a new addition, the Cultural Beacon, the project aims to work in two ways. The first is “to be seen”, in order to attract people of Halmstad to engage and practice its culture. The second is “to show”, in order to illuminate what already is there, and to build upon the resources in the existing cultural clusters. By doing so, the new addition does not only nurture the practice of the city’s culture, but even more important, it nurtures the exchange of culture both between individuals and the collectives, in order to create a more open and inviting city for its residents and visitors to take in. The program of the building consists of three parts. The maker space (to engage the city’s residents in cultural activities), the workers space (to support the existing cultural clusters with space for producing and rehearsing) and the exhibition space (to showcase the story of the city’s culture). These work both separately and collectively in order to link different groups of people and encourage exchange of culture.

No description available.

Cette thèse s'inscrit dans le projet FUI-2011 BELOCOPA (Bouée Éjectable pour la LOcalisation et la COllecte des Paramètres de vol d'un Aéronef abîmé en mer). Il s'agissait de concevoir et de développer un équipement embarqué, extractible et autonome pour localiser rapidement et avec précision un aéronef abîmé en mer et récupérer par liaisons radio les principales données de vol à partir d'un patrouilleur maritime. Le but de cette thèse, au sein de l'Institut Fresnel, concernait l'étude et la réalisation de l'antenne principale de la balise. Cette antenne devait être très flexible et de petites dimensions pour être pliée et insérée dans un espace réduit de la balise et résistante lors son déploiement après son éjection de l'avion. La première partie du travail a eu pour objectif de caractériser en terme de permittivité les différents matériaux diélectriques entrant dans la constitution de la balise, à savoir les substrats sur lesquels sont fixées les antennes et le radôme. La deuxième partie de la thèse porte sur la conception d'antennes multi-bandes fonctionnant en modes dipolaires sur le plan de fréquences du cahier des charges du projet. Ces antennes ont la particularité d'être extrêmement souples. Cette souplesse a été obtenue en réalisant des motifs métalliques rayonnants sur une toile polyamide. Plusieurs motifs ont été étudiés et testés pour converger vers une antenne méandre fonctionnant à trois fréquences distinctes. A l'issue de cette étude, un prototype de l'antenne finale positionnée dans son radôme constitue le dernier maillon du prototype de la balise de détresse du projet BELOCOPA. / This thesis is part of the BELOCOPA project FUI-2011 (BELOCOPA means Ejected Buoy to LOcalize and COllect the data of a crashed plane in sea). It was about designing and developing an on-board, removable and autonomous, equipment to localize quickly and precisely an aircraft crashed in the sea, and to collect by telecommunication the main flight data from a patrol boat. The aim of this thesis, in the Fresnel Institute, was the study and the realization of the main antenna of the beacon. This antenna had to be very flexible with small dimensions to be folded and integrated in a reduced space of the beacon, and had to be strong during its deployment after the ejection of the plane. The aim of the first part of the work was to characterize in term of permittivity the different dielectric materials included in the composition of the beacon, namely the substrates of the antennas and the radome. The second part of the thesis was on the design of multi-band antennas working in dipolar modes on the frequency plan of the specification of the project. The characteristic of these antennas is to be very flexible. This flexibility was obtained realizing metal radiating pattern on a polyamide material. Several patterns have been studied and tested to get the final antenna with meander working at three different resonance frequencies. Following this study, a prototype of the final antenna integrated in the radome is the last link of the prototype of the distress beacon BELOCOPA.

A fully functional proof of concept radio receiver for detecting avalanche beacons atthe frequency 457 kHz was constructed in the work of this master thesis. The radioreceiver is intended to be mounted on an unmanned aerial vehicle (UAV or drone)and used to aid the mountain rescue teams by reducing the rescue time in findingavalanche victims carrying a transmitting beacon. The main parts of this master thesisinvolved hardware requirement analysis, software development, digital signalprocessing and wireless communications. The radio receiver was customized to receive low power signal levels becausemagnetic antennas are used and the avalanche beacon will operate in the reactive nearfield of the radio receiver. Noise from external sources has a significant impact on theperformance of the radio receiver. This master thesis allows for straightforward further development and refining of theradio receiver due to the flexibility of the used open-source software development kitGNU Radio where the digital signal processing was performed.