Medium access control design for distributed opportunistic radio networks

Existing wireless networks are characterized by a fixed spectrum assignment policy. However, the scarcity of available spectrum and its inefficient usage demands for a new communication paradigm to exploit the existing spectrum opportunistically. Future Cognitive Radio (CR) devices should be able to sense unoccupied spectrum and will allow the deployment of real opportunistic networks. Still, traditional Physical (PHY) and Medium Access Control (MAC) protocols are not suitable for this new type of networks because they are optimized to operate over fixed assigned frequency bands. Therefore, novel PHY-MAC cross-layer protocols should be developed to cope with the specific features of opportunistic networks. This thesis is mainly focused on the design and evaluation of MAC protocols for Decentralized Cognitive Radio Networks (DCRNs). It starts with a characterization of the spectrum sensing framework based on the Energy-Based Sensing (EBS) technique considering multiple scenarios. Then, guided by the sensing results obtained by the aforementioned technique, we present two novel decentralized CR MAC schemes: the first one designed to operate in single-channel scenarios and the second one to be used in multichannel scenarios. Analytical models for the network goodput, packet service time and individual transmission probability are derived and used to compute the performance of both protocols. Simulation results assess the accuracy of the analytical models as well as the benefits of the proposed CR MAC schemes.

Rely-guarantee protocols for safe interference over shared memory

Mutable state can be useful in certain algorithms, to structure programs, or for efficiency purposes. However, when shared mutable state is used in non-local or nonobvious ways, the interactions that can occur via aliases to that shared memory can be a source of program errors. Undisciplined uses of shared state may unsafely interfere with local reasoning as other aliases may interleave their changes to the shared state in unexpected ways. We propose a novel technique, rely-guarantee protocols, that structures the interactions between aliases and ensures that only safe interference is possible. We present a linear type system outfitted with our novel sharing mechanism that enables controlled interference over shared mutable resources. Each alias is assigned separate, local roles encoded in a protocol abstraction that constrains how an alias can legally use that shared state. By following the spirit of rely-guarantee reasoning, our rely-guarantee protocols ensure that only safe interference can occur but still allow many interesting uses of shared state, such as going beyond invariant and monotonic usages. This thesis describes the three core mechanisms that enable our type-based technique to work: 1) we show how a protocol models an alias’s perspective on how the shared state evolves and constrains that alias’s interactions with the shared state; 2) we show how protocols can be used while enforcing the agreed interference contract; and finally, 3) we show how to check that all local protocols to some shared state can be safely composed to ensure globally safe interference over that shared memory. The interference caused by shared state is rooted at how the uses of di↵erent aliases to that state may be interleaved (perhaps even in non-deterministic ways) at run-time. Therefore, our technique is mostly agnostic as to whether this interference was the result of alias interleaving caused by sequential or concurrent semantics. We show implementations of our technique in both settings, and highlight their di↵erences. Because sharing is “first-class” (and not tied to a module), we show a polymorphic procedure that enables abstract compositions of protocols. Thus, protocols can be specialized or extended without requiring specific knowledge of the interference produce by other protocols to that state. We show that protocol composition can ensure safety even when considering abstracted protocols. We show that this core composition mechanism is sound, decidable (without the need for manual intervention), and provide an algorithm implementation.

Which communication strategy should a male luxury (fashion) brand – associated with a luxury car brand – develop, in order to increase its awareness in Europe

This work project explores how a male luxury (fashion) brand (subsidiary) that is associated with a luxury car brand (parent company) should develop its communication strategy in order to increase awareness in Europe. For this purpose a quantitative research was conducted. The aim was to find out whether the company in question had low brand awareness among European luxury consumers. Hereafter, a qualitative research revealed important insights in regard to luxury communication among male luxury consumers. Both the results of the research and the recommendations of luxury experts laid the foundation for the development of a solution-oriented communication strategy. The result of the analysis crystallizes the importance of the shared heritage and the synergistic effects, of which the subsidiary should make vast use when communicating.

Methodology for WSN communication technologies automated field tests

Wireless Sensor Networks(WSN) are networks of devices used to sense and act that applies wireless radios to communicate. To achieve a successful implementation of a wireless device it is necessary to take in consideration the existence of a wide variety of radios available, a large number of communication parameters (payload, duty cycle, etc.) and environmental conditions that may affect the device’s behaviour. However, to evaluate a specific radio towards a unique application it might be necessary to conduct trial experiments, with such a vast amount of devices, communication parameters and environmental conditions to take into consideration the number of trial cases generated can be surprisingly high. Thus, making trial experiments to achieve manual validation of wireless communication technologies becomes unsuitable due to the existence of a high number of trial cases on the field. To overcome this technological issue an automated test methodology was introduced, presenting the possibility to acquire data regarding the device’s behaviour when testing several technologies and parameters that care for a specific analysis. Therefore, this method advances the validation and analysis process of the wireless radios and allows the validation to be done without the need of specific and in depth knowledge about wireless devices.

The impact of in-store activations (communication) in the consumer's emotions

Consumer behavior: Sport Zone. The analysis of "The impact of in-store activations (communication) in the consumer's emotions" Several studies have been conducted on the consumer behavior. This study aims to analyze and understand which factors are important to consumers’ emotions when the purchase decision occurs, the brand awareness, brand loyalty and the campaigns/activations’ impact in the above factors. Two research surveys were conducted to realize this study, the first online and the other was an interview to the Agency Up Partner who conceived and put into practice this Fitness campaign. First of all, was the consumer’s survey, a survey with 100 answers, to understand which factors are taken into account when a campaign in-store is held, in which the atmosphere is mainly used to arouse consumer’s desire to purchase, and also emotions. Second, the interview with the agency was realized to find out on what they were based on when they delineate it, and if the raise of emotions was taken into account in the origin of it. Concluding, emotions have a significant impact on formation of consumer in-store behavior, satisfaction and loyalty. As we could assay through of how this Fitness campaign was carried out as well as the optimal feedback received by consumers, improved attention over in-store marketing activity strongly influences consumer behavior at the point of purchase. “Sport Zone: A new store concept where the love for sports is combined with functionality”

Corporate social responsability in advergames: Adjusting communication to the kids of today

Field lab: Consumer insights

The global shopper & brands communication at airports

This project aims to illuminate two perspectives on travel retail. On the one hand, it describes the main character of the shopping scenario at airports, namely the Global Shopper. It covers the entire profile of the referred character, the main nationalities that represent him and the current shopping trends of the passenger. Also estimates of the booming nationalities and the future purchasing trends are accurately presented. On the other hand, the travel retail market is analyzed from the airport brands’ perspective. It is described what is currently done in terms of brands communication in the top ten airports around the world and the expected future market retail trends. To accurately explore the Global Shopper behavior and purchasing preferences, a market research was conducted with a sample of 128 respondents, male and female, from different nationalities, age groups, occupation and education backgrounds. The essay tests hypothesis regarding the relevance of several variables in the purchasing process of the Global Shopper in order to understand the most pleasant way to approach consumers in travel retail. The main variables studied concern the reasons to shop at airports, to whom the passenger shops, the preferred category and brand of purchase, feelings while shopping abroad, impulsive buying behavior, brand loyalty, the use of mobile devices in the shopping process, brands communication at airports, pre-ordering online and the attitude towards self-service stores. Some findings were in accordance with expectations, while others were a surprise and may produce valuable recommendations for future travel retail practices. 4 The main relevant results concern two areas, namely pre-ordering online and self-service stores. Results showed a certain stress about not having enough time to choose between the various offerings in travel retail, as well as difficulty in dealing with crowed stores. However, pre-ordering online was not common, which would be an initiative that could solve the discomfort at airport’s stores. Moreover, self-service would promote efficiency in stores allowing passengers to save time if they already know how to go through the shopping process by themselves. Another possible recommendation concerns differentiating the strategy in travel retail for the two genders. Some differences were found in the categories bought by male and female, as well as to how brands should shape their approach concerning the demands of each gender.