Search results for " adaptive"
showing 10 items of 157 documents
Robust Adaptive Modulation and Coding (AMC) selection in LTE systems using reinforcement learning
2014
Adaptive Modulation and Coding (AMC) in LTE networks is commonly employed to improve system throughput by ensuring more reliable transmissions. Most of existing AMC methods select the modulation and coding scheme (MCS) using pre-computed mappings between MCS indexes and channel quality indicator (CQI) feedbacks that are periodically sent by the receivers. However, the effectiveness of this approach heavily depends on the assumed channel model. In addition CQI feedback delays may cause throughput losses. In this paper we design a new AMC scheme that exploits a reinforcement learning algorithm to adjust at run-time the MCS selection rules based on the knowledge of the effect of previous AMC d…
Adaptive learning of compressible strings
2020
Suppose an oracle knows a string $S$ that is unknown to us and that we want to determine. The oracle can answer queries of the form "Is $s$ a substring of $S$?". In 1995, Skiena and Sundaram showed that, in the worst case, any algorithm needs to ask the oracle $\sigma n/4 -O(n)$ queries in order to be able to reconstruct the hidden string, where $\sigma$ is the size of the alphabet of $S$ and $n$ its length, and gave an algorithm that spends $(\sigma-1)n+O(\sigma \sqrt{n})$ queries to reconstruct $S$. The main contribution of our paper is to improve the above upper-bound in the context where the string is compressible. We first present a universal algorithm that, given a (computable) compre…
Capture Aware Sequential Waterfilling for LoraWAN Adaptive Data Rate
2020
LoRaWAN (Long Range Wide Area Network) is emerging as an attractive network infrastructure for ultra low power Internet of Things devices. Even if the technology itself is quite mature and specified, the currently deployed wireless resource allocation strategies are still coarse and based on rough heuristics. This paper proposes an innovative "sequential waterfilling" strategy for assigning Spreading Factors (SF) to End-Devices (ED). Our design relies on three complementary approaches: i) equalize the Time-on-Air of the packets transmitted by the system's EDs in each spreading factor's group; ii) balance the spreading factors across multiple access gateways, and iii) keep into account the c…
Adaptive independent sticky MCMC algorithms
2018
In this work, we introduce a novel class of adaptive Monte Carlo methods, called adaptive independent sticky MCMC algorithms, for efficient sampling from a generic target probability density function (pdf). The new class of algorithms employs adaptive non-parametric proposal densities which become closer and closer to the target as the number of iterations increases. The proposal pdf is built using interpolation procedures based on a set of support points which is constructed iteratively based on previously drawn samples. The algorithm's efficiency is ensured by a test that controls the evolution of the set of support points. This extra stage controls the computational cost and the converge…
Analysis and control of a seven mode truncation of the Kolmogorov flow with drag.
2008
The transition from laminar to chaotic motion in a viscous fluid flow is investigated by analyzing a seven dimensional dynamical system obtained by a truncation of the Fourier modes for the Kolmogorov flow with drag friction. Analytical expressions of the bifurcation curves are obtained and a sequence of period doubling bifurcations are numerically observed as the Reynoplds number is increased for fixed values of the drag parameter. An adaptive stabilization of the system trajectories to an equilibrium point or to a periodic orbit is obtained through a model reference approach which makes the control global.
Advanced fluorescence microscopy for in vivo imaging of neuronal activity
2019
Brain function emerges from the coordinated activity, over time, of large neuronal populations placed in different brain regions. Understanding the relationships of these specific areas and disentangling the contributions of individual neurons to overall function remain central goals for neuroscience. In this scenario, fluorescence microscopy has been proved as the tool of choice for in vivo recording of brain activity. Optical advances combined with genetically encoded indicators allow a large flexibility in terms of spatiotemporal resolution and field of view while keeping invasiveness in living animals to a minimum. Here we describe the latest advancements in the field of linear and nonl…
An MAS-based subjective model for indoor adaptive thermal comfort
2015
The achievement of high level personalized sets of comfort parameters is contemplated within the more general context of the so-called smart buildings, where people, by means of the new communication technologies, become active actors to the process of the singling out and control of the best indoor conditions. This Dynamic Intelligence approach would usefully contribute to a better energy efficient and environmental friendly management of buildings. Multi-Agent schemes are suitable tools in this aim, since they are able to manage the user-building-plant system where the adaptivity of people to the indoor conditions is suitably achieved. In this paper a contribution to a development of the …
An ecological dynamics rationale to explain home advantage in professional football
2016
Despite clear findings, research on home advantage in team sports lacks a comprehensive theoretical rationale for understanding why this phenomenon is so compelling. The aim of this study was to provide an explanatory theoretical rationale in ecological dynamics for the influence of home advantage observed in research on professional football. We recorded 30 competitive matches and analyzed 13958 passes, from one highly successful team in the Portuguese Premier League, during season 2010/2011. Performance data were analyzed using the Match Analysis Software—Amisco[Formula: see text] (version 3.3.7.25), allowing us to characterize team activity profiles. Results were interpreted from an ecol…
Arc crossing minimization in graphs with GRASP
2001
Graphs are commonly used to represent information in many fields of science and engineering. Automatic drawing tools generate comprehensible graphs from data, taking into account a variety of properties, enabling users to see important relationships in the data. The goal of limiting the number of arc crossings is a well-admitted criterion for a good drawing. In this paper, we present a Greedy Randomized Adaptive Search Procedure (GRASP) for the problem of minimizing arc crossings in graphs. Computational experiments with 200 graphs with up to 350 vertices are presented to assess the merit of the method. We show that simple heuristics are very fast but result in inferior solutions, while hig…
NATURALLY AVAILABLE SOLUTIONS FOR BUILDING NEW METABOLIC TERRITORIES
2021
Building new metabolic territories is a proactive way of responding to the challenges and precariousness of the contemporary city. Byintegrating solutions inspired by new scientific advances in urban ecology, cities are able to address some of the environmental threats. Many European cities are implementing alternative nature-based solutions to protect their health and tackle water scarcity, land consumption and climate change, to increase citizens' well-being. Wellbeing and health (Agenda 2030) are the most important analytical parameters for measuring the results and impacts of environmental project actions. With this in mind, the study presents a "nature-action" project hypothesis for wh…