Results 31 to 40 of about 1,967 (149)

Managing for resilience with ecological structure: Portfolio effects in the Laurentian Great Lakes

open access: yesFrontiers in Ecology and the Environment, EarlyView.
Combined effects of global change, including land conversion, biological invasions, and overexploitation, have degraded the resilience of ecosystems and the services they provide. Here, we identify key ecological structures and processes that can be targeted by management to improve resilience at scales ranging from single species to entire landscapes.
Kayla RS Hale   +15 more
wiley   +1 more source

Nowcasting World Trade With Machine Learning: A Three‐Step Approach

open access: yesJournal of Forecasting, EarlyView.
ABSTRACT We nowcast world trade using machine learning, distinguishing between tree‐based methods (random forest and gradient boosting) and their linear‐regression‐based counterparts (macroeconomic random forest and gradient boosting—linear). While much less used in the literature, the latter are found to outperform not only the tree‐based techniques ...
Menzie Chinn   +2 more
wiley   +1 more source

Stochastic approximation with long range dependent and heavy tailed noise [PDF]

open access: yes, 2012
Stability and convergence properties of stochastic approximation algorithms are analyzed when the noise includes a long range dependent component (modeled by a fractional Brownian motion) and a heavy tailed component (modeled by a symmetric stable ...
Borkar, V. S.   +3 more
core   +1 more source

Asynchronous stochastic approximations with asymptotically biased errors and deep multi-agent learning

open access: yes, 2018
Asynchronous stochastic approximations (SAs) are an important class of model-free algorithms, tools and techniques that are popular in multi-agent and distributed control scenarios. To counter Bellman's curse of dimensionality, such algorithms are coupled with function approximations.
Ramaswamy, Arunselvan   +2 more
openaire   +2 more sources

Microbiome and aging: Trajectories of microbiome age across human ecosystems and their systemic effects

open access: yesiMeta, EarlyView.
Microbiome age (MA) has emerged as an innovative biomarker of biological aging, reflecting host aging trajectories through dynamic alterations in microbial composition, function, and host–microbe interactions across multiple body ecosystems. Diverse computational strategies—including traditional machine learning, deep learning, and multi‐omics ...
Zhexin Ni   +26 more
wiley   +1 more source

Accurate BER Analysis of QPSK Modulated Asynchronous DS-CDMA Systems Communicating over Rayleigh Channels [PDF]

open access: yes, 2006
The accurate average BER calculation of an asynchronous DS-CDMA system using random spreading sequences is studied in Rayleigh fading channels. An accurate closed-form expression is derived for the conditional characteristic function of the multiple ...
Liu, X., Hanzo, L.
core  

A Framework for Subgroup Dynamics Through the System Dynamics Lens: An Integrative Review of the Attribute and the Network Views

open access: yesJournal of Organizational Behavior, EarlyView.
ABSTRACT Subgroups are dynamic entities evolving constantly in response to changing contexts and time. Although scholars from both the attribute and the network views have acknowledged that subgroups are inherently complex and fluid, research in these traditions has remained bifurcated, with limited efforts to integrate the two perspectives to more ...
Jinhee Moon   +3 more
wiley   +1 more source

Fault Detection of Electric Motors via Symmetrized Dot Pattern‐Based Features

open access: yesInternational Journal of Mechanical System Dynamics, EarlyView.
ABSTRACT This study proposes a novel symmetrized dot pattern (SDP) approach using designed SDP‐based features, extracted from transformed vibration signals, for fault detection. These features describe the compactness, inclination, and shape of the “snowflake” diagram distributions.
Mario Spirto   +6 more
wiley   +1 more source

The dual role of detritus as resource and habitat: integrating non‐trophic processes to ecosystem dynamics

open access: yesOikos, EarlyView.
The diversity of ecological interactions, both trophic and non‐trophic, is central to understanding the assembly of communities. However, we have yet to study non‐trophic processes through their action on ecosystem compartments such as detritus involved in both recycling and habitat provisioning.
Frederic Guichard   +2 more
wiley   +1 more source

A Unified Exact BER Performance Analysis of Asynchronous DS-CDMA Systems Using BPSK Modulation over Fading Channels [PDF]

open access: yes, 2007
—An asynchronous binary DS-CDMA system using random spreading sequences is considered when communicating over various fading channels. New closed-form expressions are derived for the conditional Characteristic Function (CF) of the multiple access ...
Liu, Xiang, Hanzo, Lajos
core  

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