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See detailA Novel Heap-based Pilot Assignment for Full Duplex Cell-Free Massive MIMO with Zero-Forcing
Nguyen, Van Hieu; Nguyen, van Dinh UL; Dobre, Octavia A. et al

in IEEE International Conference on Communications (2020, June 07)

This paper investigates the combined benefits of full-duplex (FD) and cell-free massive multiple-input multipleoutput (CF-mMIMO), where a large number of distributed access points (APs) having FD ... [more ▼]

This paper investigates the combined benefits of full-duplex (FD) and cell-free massive multiple-input multipleoutput (CF-mMIMO), where a large number of distributed access points (APs) having FD capability simultaneously serve numerous uplink and downlink user equipments (UEs) on the same time-frequency resources. To enable the incorporation of FD technology in CF-mMIMO systems, we propose a novel heapbased pilot assignment algorithm, which not only can mitigate the effects of pilot contamination but also reduce the involved computational complexity. Then, we formulate a robust design problem for spectral efficiency (SE) maximization in which the power control and AP-UE association are jointly optimized, resulting in a difficult mixed-integer nonconvex programming. To solve this problem, we derive a more tractable problem before developing a very simple iterative algorithm based on inner approximation method with polynomial computational complexity. Numerical results show that our proposed methods with realistic parameters significantly outperform the existing approaches in terms of the quality of channel estimate and SE. [less ▲]

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See detailToward an SDN-based Data Collection Scheme for Vehicular Fog Computing
Boualouache, Abdelwahab UL; Soua, Ridha UL; Engel, Thomas UL

in IEEE International Conference on Communications ICC'2020 (2020, June 07)

With the integration of fog networks and vehicular networks, Vehicular Fog Computing (VFC) is a promising paradigm to efficiently collect data for improving safety, mobility, and driver experience during ... [more ▼]

With the integration of fog networks and vehicular networks, Vehicular Fog Computing (VFC) is a promising paradigm to efficiently collect data for improving safety, mobility, and driver experience during journeys. To this end, we exploit the Software-Defined Networking (SDN) paradigm to propose a fully-programmable, self-configurable, and context-aware data collection scheme for VFC. This scheme leverages a stochastic model to dynamically estimate the number of fog stations to be deployed. Our simulation results demonstrate that our proposed scheme provides lower latency and higher resiliency compared to classical data collection schemes. [less ▲]

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See detailAgency and Structure Revisited with Youth Responses to Gendered (Spatial) Mobilities in the EU
Samuk, Sahizer UL; Schlimbach, Tabea; Kmiotek-Meier, Emilia Alicja UL et al

in Border Crossings (2020), 10

Young people involved in geographical mobility face diverse gendered mobility settings and gender inequalities. How do the youth involved in diverse mobility types deal with adverse circumstances caused ... [more ▼]

Young people involved in geographical mobility face diverse gendered mobility settings and gender inequalities. How do the youth involved in diverse mobility types deal with adverse circumstances caused by gender beliefs and gender prejudices? To answer this question, problem-centred interviews with young people (18-29) are analysed using Grounded Theory. These young people are European citizens and they are involved in five mobility types: higher education, employment, voluntary work, vocational education & training, and entrepreneurship. We apply Emirbayer and Mische’s (1998) categories (iterational, projective and practical-evaluative) to the analysis of gendered mobility narratives as unequal gender perceptions reveal themselves in the context of different types of youth mobility. The analysis allows to see the ways young people reflect on their actions: refusal of gender beliefs, acceptance or rejection of gendered prejudices, individual vs. collective solutions, demand for equality in numbers, comparison of gendered workplaces and assumption of leadership in initiating mobility. At the same time, we observe how geographical mobilities can increase the critical sensibility of youth towards gender inequalities, contributing to new conceptualisation of agentic responses to structural constraints. [less ▲]

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See detailThe relevance of risk disclosure and the role of readability and comparability
Weber, Véronique UL; Muessig, Anke UL

Scientific Conference (2020, June 05)

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See detailMagnetic correlations in polycrystalline Tb0.15Co0.85
Bersweiler, Mathias UL; Bender, Philipp Florian UL; Peral Alonso, Inmaculada UL et al

in Journal of Physics: D Applied Physics (2020), 53

Detailed reference viewed: 60 (6 UL)
See detailSurface Energy Modification of Filter Media to achieve optimal Performance Characteristics in select Applications
Staudt, Johannes UL

Doctoral thesis (2020)

The surface modification of modern filter media is examined from the perspective of the energetic properties and how they influence select filtration applications. In contrast to the known mechanical ... [more ▼]

The surface modification of modern filter media is examined from the perspective of the energetic properties and how they influence select filtration applications. In contrast to the known mechanical filtration mechanisms, which are mainly applicable to the solid-liquid separations, new findings strongly suggest that direct interaction forces between the filter and the functional fluids must be taken into account in order to achieve sufficient efficiencies. Separation processes of liquid phases such as liquidliquid coalescence (LLC) or the treatment of process gases with liquid-gas coalescence (LGC) require special properties of filter media with regard to the degree of interaction with these phases. These include but are not limited to surface energy, wettability, chemical resistance, etc. The focus falls increasingly on eliminating the undesired interactions of modern filters with the fluid to be filtered. Filtration with modern fine filter media can result in undesired additive removal (ADDREM), particularly of those additives that are not fully dissolved in carrier fluid. Specifically this refers to the removal of antifoamants from gear oils, which lead to serious consequential damage of those systems. The interfacial interactions between the filter media and the functional fluids are also responsible for other effects such as the highly undesirable phenomenon of electrostatic charging/discharging (ESC/ESD) during the filtration of low-conductivity oils. In this work, the effect of the surface energy modification, in particular, is examined in greater detail. Ultimately, the surface energy of modern filter media is characterized and modified in order to optimize their performance in select applications. The work also presents some examples that illustrate the importance of surface energy in highly challenging filtration applications. [less ▲]

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See detailRouting Strategies and Content Dissemination Techniques for Software-Defined Vehicular Networks
di Maio, Antonio UL

Doctoral thesis (2020)

Over the past years, vehicular networking has enabled a wide range of new applications that improve vehicular safety, efficiency, comfort, and environmental impact. Vehicular networks, however, normally ... [more ▼]

Over the past years, vehicular networking has enabled a wide range of new applications that improve vehicular safety, efficiency, comfort, and environmental impact. Vehicular networks, however, normally operate in communication-hostile environments and are characterized by dynamic topologies and volatile links, making it challenging to guarantee Quality of Service (QoS) and reliability of vehicular applications. To this end, the present work explores how the centralized coordination offered by Software-Defined Networking can improve the Quality of Service in vehicular networks, particularly for Vehicle-to-Vehicle (V2V) unicast routing and content dissemination. With regard to V2V routing, this work motivates the case for centralized network coordination by studying the performance of traditional MANET routing protocols when applied to urban VANETs, showing that they cannot provide satisfactory performance for modern vehicular applications because of their limited global network awareness, slow convergence, and high signaling. Hence, this work proposes and validates a centralized Multi-Flow Congestion-Aware Routing (MFCAR) algorithm to allocate multiple data flows on V2V routes. The first novelty of MFCAR is the SDN-based node-busyness estimation technique. The second novelty is the enhancement of the path-cost formulation as a linear combination of path length and path congestion, allowing the user application to fine-tune its QoS requirements between throughput and delay. Concerning content dissemination, this work proposes a Fairness- and Throughput-Enhanced Scheduling for Content Dissemination in VANETs (ROADNET), a centralized strategy to improve the tradeoff between data throughput and user fairness in deterministic vehicular content dissemination. ROADNET’s main novelties are the design of a graph-based multi-channel transmission scheduler and the enforcement of a transmission-priority policy that prevents user starvation. As additional contributions, the present work proposes a heuristic for the centralized selection of opportunistic content dissemination parameters and discusses the main security issues in Software-Defined Vehicular Networking (SDVN) along with possible countermeasures. The proposed techniques are evaluated in realistic scenarios (LuST), using discrete-event network simulators (OMNeT++) and microscopic vehicular-mobility simulators (SUMO). It is shown that MFCAR can improve PDR, throughput and delay for unicast V2V routing up to a five-fold gain over traditional algorithms. ROADNET can increase content dissemination throughput by 36% and user fairness by 6% compared to state-of-the-art techniques, balancing the load over multiple channels with a variance below 1%. [less ▲]

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See detailEnhancing CoAP Group Communication to Support mMTC Over Satellite Networks
Soua, Ridha UL; Palattella, Maria Rita UL; Stemper, André UL et al

in IEEE International Conference on Communications (ICC) (2020, June)

Massive MTC (mMTC) is one of the application scenarios that upcoming 5G networks are expected to support. Satellites come into play in mMTC to complement and extend terrestrial networks in under-served ... [more ▼]

Massive MTC (mMTC) is one of the application scenarios that upcoming 5G networks are expected to support. Satellites come into play in mMTC to complement and extend terrestrial networks in under-served areas, where several services can benefit from the adoption of a group communication model. The IETF has specifically standardized the usage of CoAP group communication. However, CoAP responses are still sent in unicast from each single CoAP server to the CoAP client, which results in a substantial traffic load. Such problem becomes more severe in integrated IoT-Satellite networks given the limited bandwidth of the satellite return channel and the large number of IoT devices in a mMTC scenario. To reduce network traffic overhead in group communication and improve the network responsiveness, this paper proposes an aggregation scheme for the CoAP group communication in combination with Observer pattern and proxying. Results obtained by using the openSAND emulator and CoAPthon library corroborate the merit of our optimization in terms of overhead reduction and delay. [less ▲]

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See detailSuccessive Convex Approximation for Transmit Power Minimization in SWIPT-Multicast Systems
Gautam, Sumit UL; Lagunas, Eva UL; Kisseleff, Steven UL et al

Scientific Conference (2020, June)

We propose a novel technique for total transmit power minimization and optimal precoder design in wireless multi-group (MG) multicasting (MC) systems. The considered framework consists of three different ... [more ▼]

We propose a novel technique for total transmit power minimization and optimal precoder design in wireless multi-group (MG) multicasting (MC) systems. The considered framework consists of three different systems capable of handling heterogeneous user types viz., information decoding (ID) specific users with conventional receiver architectures, energy harvesting (EH) only users with non-linear EH module, and users with joint ID and EH capabilities having separate units for the two operations, respectively. Each user is categorized under unique group(s), which can be of MC type specifically meant for ID users, and/or an energy group consisting of EH explicit users. The joint ID and EH users are a part of the (last) EH group as well as any one of the MC groups distinctly. In this regard, we formulate an optimization problem to minimize the total transmit power with optimal precoder designs for the three aforementioned scenarios, under constraints on minimum signal-to-interference-plus-noise ratio and harvested energy by the users with respective demands. The problem may be adapted to the well-known semi-definite program, which can be typically solved via relaxation of rank-1 constraint. However, the relaxation of this constraint may in some cases lead to performance degradation, which increases with the rank of the solution obtained from the relaxed problem. Hence, we develop a novel technique motivated by the feasible-point pursuit and successive convex approximation method in order to address the rank-related issue. The benefits of the proposed method are illustrated under various operating conditions and parameter values, with comparison between the three above-mentioned scenarios. [less ▲]

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See detailLuxembourg - Recent and Pending CJEU Cases: Fiscal Unity, Taxpayers' fundamental rights and the FIAT case
Pantazatou, Aikaterini UL

in Lang, Michael; Pistone, Pasquale; Rust, Alexander (Eds.) et al CJEU: Recent Developments in Direct Taxation 2019 (2020)

Detailed reference viewed: 35 (2 UL)
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See detailEthnocentric preferences and the environment with international trade
Zanaj, Skerdilajda UL

E-print/Working paper (2020)

We define a model of international trade with two countries, two vertically differentiated goods, and heterogenous consumers concerning their willingness to pay for quality. Trade generates two sources of ... [more ▼]

We define a model of international trade with two countries, two vertically differentiated goods, and heterogenous consumers concerning their willingness to pay for quality. Trade generates two sources of pollution: the production of domestic and traded goods, and their transportation between countries. Consumers in both countries manifest home bias which translates into ethnocentric preferences: (i) consumer perceive the quality of the domestic good amplified; and (ii) consumers thrive additional satisfaction when consuming a domestic good rather than a foreign one since only the former can satisfy their sense of place. By contrast, they suffer a psychological penalty when consuming a foreign product. We investigate the role of trade costs and ethnocentric attitude in shaping the equilibrium configuration of the international duopoly. Finally, we uncover the environmental damage from production and from transport in presence of ethnocentrism. [less ▲]

Detailed reference viewed: 22 (3 UL)
See detailΤο Επιλεκτικό Πλεονέκτημα
Pantazatou, Aikaterini UL; Rodopoulos, Michail

in Christianos, Vasileios; Rodopoulos, Michail (Eds.) Δίκαιο Κρατικών Ενισχύσεων (2020)

Detailed reference viewed: 78 (1 UL)
See detailΕυρωπαϊκά Διαρθρωτικά Ταμεία και κρατικές ενισχύσεις
Pantazatou, Aikaterini UL

in Christianos, Vasileios; Rodopoulos, Michail (Eds.) Δίκαιο Κρατικών Ενισχύσεων (2020)

Detailed reference viewed: 79 (1 UL)
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See detailPostwachstum finanzieren? Grüne Finanzprodukte für veränderte Produktionslogiken
Dörry, Sabine; Schulz, Christian UL

in Lange, Bastian; Hülz, Martina; Schmid, Benedikt (Eds.) et al Postwachstumsgeographien. Raumbezüge diverser und alternativer Ökonomien (2020)

Detailed reference viewed: 19 (2 UL)
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See detailZur Wachstumsfixiertheit der Europäischen Union. Ein Diskussionsbeitrag
Schulz, Christian UL

in Schulz, Christian; Lange, Bastian; Hülz, Martina (Eds.) et al Postwachstumsgeographien. Raumbezüge diverser und alternativer Ökonomien (2020)

Detailed reference viewed: 13 (2 UL)
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See detailPostwachstumsgeographien. Raumbezüge diverser und alternativer Ökonomien
Lange, Bastian; Hülz, Martina; Schmid, Benedikt et al

Book published by Transcript (2020)

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See detailPostwachstumsgeographien. Konzeptionelle und thematische Eckpunkte der Anthologie
Schulz, Christian UL; Lange, Bastian; Hülz, Martina et al

in Lange, Bastian; Hülz, Martina; Schmid, Benedikt (Eds.) et al Postwachstumsgeographien. Raumbezüge diverser und alternativer Ökonomien (2020)

Detailed reference viewed: 12 (3 UL)