Q&A about writing experiences, skills, and publication practices in urban studies

Presentation (2019)

Q-value functions for decentralized POMDPs

in Proc Int. Joint Conf. on Autonomous Agents and Multi-Agent Systems (2007)

Planning in single-agent models like MDPs and POMDPs can be carried out by resorting to Q-value functions: a (near-) optimal Q-value function is computed in a recursive manner by dynamic programming, and ... [more ▼]

Planning in single-agent models like MDPs and POMDPs can be carried out by resorting to Q-value functions: a (near-) optimal Q-value function is computed in a recursive manner by dynamic programming, and then a policy is extracted from this value function. In this paper we study whether similar Q-value functions can be defined in decentralized POMDP models (Dec-POMDPs), what the cost of computing such value functions is, and how policies can be extracted from such value functions. Using the framework of Bayesian games, we argue that searching for the optimal Q-value function may be as costly as exhaustive policy search. Then we analyze various approximate Q-value functions that allow efficient computation. Finally, we describe a family of algorithms for extracting policies from such Q-value functions. [less ▲]

QAM to Circular Isomorphic Constellations

in 8th Advanced Satellite Multimedia Systems Conference (ASMS/SPSC), Palma de Mallorca, Spain, 2016 (2016, September)

Employing high order constellations is inevitable in order to achieve higher spectral efficiency in satellite communication systems. In DVB-S2X standard, constellations with up to 256 points have been ... [more ▼]

Employing high order constellations is inevitable in order to achieve higher spectral efficiency in satellite communication systems. In DVB-S2X standard, constellations with up to 256 points have been included. However, optimizing such high order constellations is a difficult task. In this paper we propose a very simple constellation design based on the radial map from QAM constellations to non-uniform APSK constellations. Our method provides a systematic way to generate a family of optimized high order constellations. We show that gains larger than 0.5 dB can be obtained with respect to the DVB-S2X constellations with 256 points. Even though the proposed constellations are essentially sub-optimal (in terms of maximizing the mutual information), they provide a very competitive test benchmark for the performance of high order constellations. Moreover, the proposed construction potentially allows for an efficient one-dimensional soft detection by an inverse mapping to the QAM. Finally, further optimization techniques are discussed. [less ▲]

QASBA 2013: Proceedings of the 2013 International Workshop on Quality Assurance for Service-Based Applications

Book published by ACM (2013)

QKD Simulator

Software (2014)

QKD simulator © is a web application aimed at simulating and analyzing Quantum Key Distribution protocols. The online simulator is powered by the QKD Simulation Toolkit, which has been designed and ... [more ▼]

QKD simulator © is a web application aimed at simulating and analyzing Quantum Key Distribution protocols. The online simulator is powered by the QKD Simulation Toolkit, which has been designed and implemented to support customizing a wide range of parameters for individual components and sub-protocols, e.g., the quantum channel, sifting, error estimation, information reconciliation and privacy amplification. Each simulation run provides detailed information about the intermediate and final stages of the protocol. [less ▲]

QoS-Constrained Sum-Harvested Energy Maximization in OFDMA-based Wireless Cooperative Networks

Scientific Conference (2018, December)

We investigate the performances of the time-switching (TS) and power-splitting (PS) based energy harvesting models in a two-hop relay assisted network where the end-users are capable of decoding ... [more ▼]

We investigate the performances of the time-switching (TS) and power-splitting (PS) based energy harvesting models in a two-hop relay assisted network where the end-users are capable of decoding information and harvesting energy concurrently. In particular, we consider joint resource allocation and relay selection to realize Simultaneous Wireless Transmission of Information and Energy (Wi-TIE) in a multi-carrier multi-user cooperative system where the relays employ the amplify-and-forward (AF) protocol. First, we formulate based on the TS and PS Wi-TIE architectures an optimization problem to maximize the sum of energy harvested at the end-users, taking into consideration each user's quality-of-service (QoS) requirement as well as power constraints at the transmit and relaying nodes. We then solve the formulated problem to optimize the users' Wi-TIE splitting factors along with relay-user coupling, sub-carrier-user assignment, sub-carrier pairing, and power allocation. Finally, we demonstrate the benefits of the proposed framework via numerical results. [less ▲]

Qu'est-ce qu'un Luxembourgeois? Histoire de la nationalité luxembourgeoise du Code Napoléon à nos jours

in Hemecht : Zeitschrift für Luxemburger Geschichte = Revue d'Histoire Luxembourgeoise (2006), (58/1), 73-96

Qu’est-ce qu’une "création" ? Dialogue entre art et droit

Article for general public (2011)

Qu’est-ce que la justice ?

in Le Portique (2013)

Qu'est-ce que, en droit, une exception?

in Fatin-Rouge Stefanini; Vidal-Naquet, Ariane (Eds.) La norme et ses exceptions. Quels défis pour la règle de droit ? (2014)