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Wireless local area networks (WLANs) are the most popular kind of wireless Internet connection because of their simplicity of deployment and operation. As a result, the number of devices accessing the Internet through WLANs such as laptops, smartphones, or wearables, is increasing drastically at the same time that applications' throughput requirements do. To cope with these challenges, channel bonding (CB) techniques are used for enabling higher data rates by transmitting in wider channels, thus increasing spectrum efficiency. However, important issues like higher potential co-channel and adjacent channel interference arise when bonding channels. This may harm the performance of the carrier sense multiple access (CSMA) protocol because of recurrent backoff freezing, while making nodes more sensitive to hidden node effects. In this paper, we address the following point at issue: is it convenient for high-density (HD) WLANs to use wider channels and potentially overlap in the spectrum? First, we highlight key aspects of DCB in toy scenarios through a continuous time Markov network (CTMN) model. Then, by means of extensive simulations covering a wide range of traffic loads and access point (AP) densities, we show that dynamic channel bonding (DCB) – which adapts the channel bandwidth on a per-packet transmission – significantly outperforms traditional single-channel on average. Nevertheless, results also corroborate that DCB is more prone to generate unfair situations where WLANs may starve. Contrary to most of the current thoughts pushing towards non-overlapping channels in HD deployments, we highlight the benefits of allocating channels as wider as possible to WLANs altogether with implementing adaptive access policies to cope with the unfairness situations that may appear. ; This work has been partially supported by a Gift from CISCO University Research Program (CG#890107) & Silicon Valley Community Foundation, by the Spanish Ministry of Economy and Competitiveness under the Maria de Maeztu Units of Excellence Programme (MDM-2015-0502), and by the Catalan Government under grant SGR-2017-1188. The work by S. Barrachina-Muñoz is supported by an FI grant from the Generalitat de Catalunya.

Comunicació presentada a: Proceedings of the IEEE Conference on Standards for Communications and Networking (CSCN) celebrat del 28 al 30 d'octubre a Granada, Espanya. ; The Spatial Reuse (SR) operation included in the IEEE 802.11ax-2020 (11ax) amendment aims at increasing the number of parallel transmissions in an Overlapping Basic Service Set (OBSS). However, many unknowns exist about the performance gains that can be achieved through SR. In this paper, we provide a brief introduction to the SR operation described in the IEEE 802.11ax (draft D4.0). Then, a simulation-based implementation is provided in order to explore the performance gains of the SR operation. Our results show the potential of using SR in different scenarios covering multiple network densities and traffic loads. In particular, we observe significant improvements on the channel utilization when applying SR with respect to the default configuration, thus allowing to increase the throughput and reduce the delay. Interestingly, the highest improvements provided by the SR operation are observed in the most pessimistic situations in terms of network density and traffic load. ; This work has been partially supported by the Spanish Ministry of Economy and Competitiveness under the Maria de Maeztu Units of Excellence Programme (MDM-2015-0502), by WINDMAL PGC2018-099959-BI00 (MCIU/AEI/FEDER,UE), by the Catalan Government under SGR grant for research support (2017-SGR-11888), and by a Gift from the Cisco University Research Program (CG#890107, Towards Deterministic Channel Access in High-Density WLANs) Fund, a corporate advised fund of Silicon Valley Community Foundation. The work by S. Barrachina-Munoz is supported by an FI grant from the Generalitat de Catalunya.

Comunicació presentada al International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob 2019), celebrat del 21 al 23 d'octubre de 2020 a Barcelona, Espanya. ; Next generation of wireless local area networks (WLANs) will operate in dense, chaotic and highly dynamic scenarios that in a significant number of cases may result in a low user experience due to uncontrolled high interference levels. Flexible network architectures, such as the software-defined networking (SDN) paradigm, will provide WLANs with new capabilities to deal with users' demands, while achieving greater levels of efficiency and flexibility in those complex scenarios. On top of SDN, the use of machine learning (ML) techniques may improve network resource usage and management by identifying feasible configurations through learning. ML techniques can drive WLANs to reach optimal working points by means of parameter adjustment, in order to cope with different network requirements and policies, as well as with the dynamic conditions. In this paper we overview the work done in SDN for WLANs, as well as the pioneering works considering ML for WLAN optimization. Finally, in order to demonstrate the potential of ML techniques in combination with SDN to improve the network operation, we evaluate different use cases for intelligent-based spatial reuse and dynamic channel bonding operation in WLANs using Multi-Armed Bandits. ; This work has been partially supported by the Spanish Ministry of Economy and Competitiveness under the Maria de Maeztu Units of Excellence Programme (MDM-2015-0502), by the Catalan Government under grant 2017-SGR-1188, by the Spanish Government under grant PGC2018-099959-B-I00 (MCIU/AEI/FEDER,UE), and by a Gift from the Cisco University Research Program (CG#890107, Towards Deterministic Channel Access in High-Density WLANs) Fund, a corporate advised fund of Silicon Valley Community Foundation. The work done by S. Barrachina-Mu ˜noz is supported by a FI grant from the Generalitat de Catalunya.

The process of drafting, approving and implementing the Water Framework Directive (WFD) has played a pivotal role in the water-related political agenda of the Iberian Peninsula. The WFD has provided an institutional impetus for a shift from the dominant hydraulic paradigm towards a new water governance approach. The new approach, known as the New Water Culture (NWC), predated the WFD. It was initiated in Spain and Portugal in the 1990s and has been promoted by a coalition of academics, social activists, and water managers. Given the long tradition and relevance of water debates in Spain and Portugal, the sociopolitical and territorial conflicts surrounding the implementation of the new regulatory framework are of particular significance. Legal debates about the (in)correct transposition of the WFD into Spanish and Portuguese legislation are still unresolved. Legal debates about the (in)correct transposition of the WFD into Spanish and Portuguese legislation are still unresolved. Controversies focus on issues such as the use of economic instruments, for instance cost recovery and the use of public subsidies (a key component of the hydraulic paradigm), as well as the role of public participation in decision making processes. Significant resistance has been mounted by the traditional water policy community, which continues to dominate power structures surrounding water. Throughout the long WFD implementation process, conflicting views and interests have consistently emerged with regard to the diagnosis and identification of existing pressures and the definition, evaluation and implementation of the proposed measures. Controversies have also emerged around the extensive use of exceptions which has allowed the hydraulic paradigm to persist over time. Progress towards the promised governance model, however, is taking place, with significant improvements in transparency, more accurate knowledge regarding the aquatic ecosystems services and the inclusion in water management agencies of more diverse experts including social scientists, biologists and geologists. This paper looks at the role the WFD implementation process is playing in the struggle for the transformation of water policy in Spain and Portugal. It examines this through the lens of the NWC movement.

Spatial Reuse (SR) has recently gained attention to maximize the performance of IEEE 802.11 Wireless Local Area Networks (WLANs). Decentralized mechanisms are expected to be key in the development of SR solutions for next-generation WLANs, since many deployments are characterized by being uncoordinated by nature. However, the potential of decentralized mechanisms is limited by the significant lack of knowledge with respect to the overall wireless environment. To shed some light on this subject, we show the main considerations and possibilities of applying online learning to address the SR problem in uncoordinated WLANs. In particular, we provide a solution based on Multi-Armed Bandits (MABs) whereby independent WLANs dynamically adjust their frequency channel, transmit power and sensitivity threshold. To that purpose, we provide two different strategies, which refer to selfish and environment-aware learning. While the former stands for pure individual behavior, the second one considers the performance experienced by surrounding networks, thus taking into account the impact of individual actions on the environment. Through these two strategies we delve into practical issues of applying MABs in wireless networks, such as convergence guarantees or adversarial effects. Our simulation results illustrate the potential of the proposed solutions for enabling SR in future WLANs. We show that substantial improvements on network performance can be achieved regarding throughput and fairness. ; This work has been partially supported by the Spanish Ministry of Economy and Competitiveness under the Maria de Maeztu Units of Excellence Programme (MDM-2015-0502), by the Catalan Government SGR grant for research support (2017-SGR-1188), by the European Regional Development Fund under grant TEC2015-71303-R (MINECO/FEDER), and by a Gift from the Cisco University Research Program (CG#890107, Towards Deterministic Channel Access in High-Density WLANs) Fund, a corporate advised fund of Silicon Valley Community Foundation.

This paper deals with substitution of hazardous substances in production processes for environmental and health and safety reasons, with special reference to experiences of substitution of volatile organic compounds in paints and in concrete mould release agents. Substitution in this context is seen as a particular kind of technological transfer, in which the main value of the technology lies in its environmental and health and safety performances, as a contribution to industrial sustainability. The authors identify the main actors of the substitution process (industry, trade unions, NGOs, etc.), the role they play in such a process (promoter, target group, ally or opposer) and the scene in which the action develops (i.e. the institutional and cultural framework). Building on the lessons and experiences drawn from the analysis of twenty cases in different sectors throughout the European Union, factors favouring and opposing substitution, as well as the features of "good" promoters and projects, are analysed.