Spatial Evolutionary Algorithms for Characterizing Large-Scale Spatial Groundwater-Vegetation Dynamics in Arid Region

2009 ◽  
Author(s):  
Jihua Wang ◽  
Ximing Cai ◽  
Albert J. Valocchi
Keyword(s):  
Evolutionary Algorithms ◽  
Vegetation Dynamics ◽  
Arid Region ◽  
Large Scale

scholarly journals Investigation of Improved Cooperative Coevolution for Large-Scale Global Optimization Problems

Algorithms ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 146
Author(s):  
Aleksei Vakhnin ◽  
Evgenii Sopov
Keyword(s):  
Global Optimization ◽  
Evolutionary Algorithms ◽  
Numerical Experiments ◽  
Large Scale ◽  
Optimization Problems ◽  
State Of The Art ◽  
Fixed Number ◽  
High Dimensional ◽  
Cooperative Coevolution ◽  
Large Scale Problems

Modern real-valued optimization problems are complex and high-dimensional, and they are known as “large-scale global optimization (LSGO)” problems. Classic evolutionary algorithms (EAs) perform poorly on this class of problems because of the curse of dimensionality. Cooperative Coevolution (CC) is a high-performed framework for performing the decomposition of large-scale problems into smaller and easier subproblems by grouping objective variables. The efficiency of CC strongly depends on the size of groups and the grouping approach. In this study, an improved CC (iCC) approach for solving LSGO problems has been proposed and investigated. iCC changes the number of variables in subcomponents dynamically during the optimization process. The SHADE algorithm is used as a subcomponent optimizer. We have investigated the performance of iCC-SHADE and CC-SHADE on fifteen problems from the LSGO CEC’13 benchmark set provided by the IEEE Congress of Evolutionary Computation. The results of numerical experiments have shown that iCC-SHADE outperforms, on average, CC-SHADE with a fixed number of subcomponents. Also, we have compared iCC-SHADE with some state-of-the-art LSGO metaheuristics. The experimental results have shown that the proposed algorithm is competitive with other efficient metaheuristics.

Satellite-based large-scale vegetation dynamics in ecological restoration programmes of Northern China

2018 ◽  
Vol 40 (5-6) ◽  
pp. 2296-2312 ◽  
Author(s):  
Zhitao Wu ◽  
Lu Yu ◽  
Xiaoyu Zhang ◽  
Ziqiang Du ◽  
Hong Zhang
Keyword(s):  
Ecological Restoration ◽  
Vegetation Dynamics ◽  
Large Scale ◽  
Northern China

Evolutionary Approaches and Their Applications to Distributed Systems

2010 ◽  
pp. 114-149 ◽  
Author(s):  
Thomas Weise ◽  
Raymond Chiong
Keyword(s):  
Distributed Systems ◽  
Evolutionary Algorithms ◽  
Network Topology ◽  
Large Scale ◽  
Computational Time ◽  
Distributed Environment ◽  
Rapid Changes ◽  
Np Complete ◽  
Nature Inspired Algorithms ◽  
Ubiquitous Presence

The ubiquitous presence of distributed systems has drastically changed the way the world interacts, and impacted not only the economics and governance but also the society at large. It is therefore important for the architecture and infrastructure within the distributed environment to be continuously renewed in order to cope with the rapid changes driven by the innovative technologies. However, many problems in distributed computing are either of dynamic nature, large scale, NP complete, or a combination of any of these. In most cases, exact solutions are hardly found. As a result, a number of intelligent nature-inspired algorithms have been used recently, as these algorithms are capable of achieving good quality solutions in reasonable computational time. Among all the nature-inspired algorithms, evolutionary algorithms are considerably the most extensively applied ones. This chapter presents a systematic review of evolutionary algorithms employed to solve various problems related to distributed systems. The review is aimed at providing an insight of evolutionary approaches, in particular genetic algorithms and genetic programming, in solving problems in five different areas of network optimization: network topology, routing, protocol synthesis, network security, and parameter settings and configuration. Some interesting applications from these areas will be discussed in detail with the use of illustrative examples.

scholarly journals Uncovering Dryland Woody Dynamics Using Optical, Microwave, and Field Data—Prolonged Above-Average Rainfall Paradoxically Contributes to Woody Plant Die-Off in the Western Sahel

2020 ◽  
Vol 12 (14) ◽  
pp. 2332 ◽  
Author(s):  
Paulo N. Bernardino ◽  
Martin Brandt ◽  
Wanda De Keersmaecker ◽  
Stéphanie Horion ◽  
Rasmus Fensholt ◽  
...  
Keyword(s):  
Vegetation Dynamics ◽  
Field Data ◽  
Large Scale ◽  
Biomass Accumulation ◽  
Severity Index ◽  
Important Variable ◽  
Woody Vegetation ◽  
Sudden Increase ◽  
Ecosystem Recovery ◽  
Normal Rainfall

Dryland ecosystems are frequently struck by droughts. Yet, woody vegetation is often able to recover from mortality events once precipitation returns to pre-drought conditions. Climate change, however, may impact woody vegetation resilience due to more extreme and frequent droughts. Thus, better understanding how woody vegetation responds to drought events is essential. We used a phenology-based remote sensing approach coupled with field data to estimate the severity and recovery rates of a large scale die-off event that occurred in 2014–2015 in Senegal. Novel low (L-band) and high-frequency (Ku-band) passive microwave vegetation optical depth (VOD), and optical MODIS data, were used to estimate woody vegetation dynamics. The relative importance of soil, human-pressure, and before-drought vegetation dynamics influencing the woody vegetation response to the drought were assessed. The die-off in 2014–2015 represented the highest dry season VOD drop for the studied period (1989–2017), even though the 2014 drought was not as severe as the droughts in the 1980s and 1990s. The spatially explicit Die-off Severity Index derived in this study, at 500 m resolution, highlights woody plants mortality in the study area. Soil physical characteristics highly affected die-off severity and post-disturbance recovery, but pre-drought biomass accumulation (i.e., in areas that benefited from above-normal rainfall conditions before the 2014 drought) was the most important variable in explaining die-off severity. This study provides new evidence supporting a better understanding of the “greening Sahel”, suggesting that a sudden increase in woody vegetation biomass does not necessarily imply a stable ecosystem recovery from the droughts in the 1980s. Instead, prolonged above-normal rainfall conditions prior to a drought may result in the accumulation of woody biomass, creating the basis for potentially large-scale woody vegetation die-off events due to even moderate dry spells.

scholarly journals Big Archive-Assisted Ensemble of Many-Objective Evolutionary Algorithms

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Wen Zhong ◽  
Jian Xiong ◽  
Anping Lin ◽  
Lining Xing ◽  
Feilong Chen ◽  
...  
Keyword(s):  
Evolutionary Algorithms ◽  
Large Scale ◽  
Optimization Problems ◽  
Experimental Studies ◽  
Evolutionary Process ◽  
Superior Performance ◽  
Nondominated Solutions ◽  
Environmental Selection ◽  
Computational Resources ◽  
Better Than

Multiobjective evolutionary algorithms (MOEAs) have witnessed prosperity in solving many-objective optimization problems (MaOPs) over the past three decades. Unfortunately, no one single MOEA equipped with given parameter settings, mating-variation operator, and environmental selection mechanism is suitable for obtaining a set of solutions with excellent convergence and diversity for various types of MaOPs. The reality is that different MOEAs show great differences in handling certain types of MaOPs. Aiming at these characteristics, this paper proposes a flexible ensemble framework, namely, ASES, which is highly scalable for embedding any number of MOEAs to promote their advantages. To alleviate the undesirable phenomenon that some promising solutions are discarded during the evolution process, a big archive that number of contained solutions be far larger than population size is integrated into this ensemble framework to record large-scale nondominated solutions, and also an efficient maintenance strategy is developed to update the archive. Furthermore, the knowledge coming from updating archive is exploited to guide the evolutionary process for different MOEAs, allocating limited computational resources for efficient algorithms. A large number of numerical experimental studies demonstrated superior performance of the proposed ASES. Among 52 test instances, the ASES performs better than all the six baseline algorithms on at least half of the test instances with respect to both metrics hypervolume and inverted generational distance.

Extreme Value Metaheuristics and Coupled Mapped Lattice Approaches for Gas Turbine-Absorption Chiller Optimization

2021 ◽  
pp. 283-312
Author(s):  
Timothy Ganesan ◽  
Pandian Vasant ◽  
Igor Litvinchev ◽  
Mohd Shiraz Aris
Keyword(s):  
Evolutionary Algorithms ◽  
Gas Turbine ◽  
Real World ◽  
Large Scale ◽  
Extreme Value ◽  
Optimization Techniques ◽  
Coupled Map Lattice ◽  
Engineering Systems ◽  
Absorption Chiller ◽  
Random Number Generators

The increasing complexity of engineering systems has spurred the development of highly efficient optimization techniques. This chapter focuses on two novel optimization methodologies: extreme value stochastic engines (random number generators) and the coupled map lattice (CML). This chapter proposes the incorporation of extreme value distributions into stochastic engines of conventional metaheuristics and the implementation of CMLs to improve the overall optimization. The central idea is to propose approaches for dealing with highly complex, large-scale multi-objective (MO) problems. In this work the differential evolution (DE) approach was employed (incorporated with the extreme value stochastic engine) while the CML was employed independently (as an analogue to evolutionary algorithms). The techniques were then applied to optimize a real-world MO Gas Turbine-Absorption Chiller system. Comparative analyses among the conventional DE approach (Gauss-DE), extreme value DE strategies, and the CML were carried out.

Which hydro-meteorological variables control large-scale photosynthesis?

2020 ◽  
Author(s):  
Wantong Li ◽  
Mirco Migliavacca ◽  
Yunpeng Luo ◽  
René Orth
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Vegetation Dynamics ◽  
Large Scale ◽  
Global Analysis ◽  
Spatial Scales ◽  
Meteorological Variables ◽  
Climate Projections ◽  
Net Radiation ◽  
Near Surface

<p>Vegetation dynamics are determined by a multitude of hydro-meteorological variables, and this interplay changes in space and time. Due to its complexity, it is still not fully understood at large spatial scales. This knowledge gap contributes to increased uncertainties in future climate projections because large-scale photosynthesis is influencing the exchange of energy and water between the land surface and the atmosphere, thereby potentially impacting near-surface weather. In this study, we explore the relative importance of several hydro-meteorological variables for vegetation dynamics. For this purpose, we infer the correlations of anomalies in temperature, precipitation, soil moisture, VPD, surface net radiation and surface downward solar radiation with respective anomalies of photosynthetic activity as inferred from Sun-Induced chlorophyll Fluorescence (SIF). To detect changing hydro-meteorological controls across different climate conditions, this global analysis distinguishes between climate regimes as determined by long-term mean aridity and temperature. The results show that soil moisture was the most critical driver with SIF in the simultaneous correlation with dry and warm conditions, while temperature and VPD was both influential on cold and wet regimes during the study period 2007-2018. We repeat our analysis by replacing the SIF data with NDVI, as a proxy for vegetation greenness, and find overall similar results, except for surface net radiation expanding controlled regions on cold and wet regimes. As the considered hydro-meteorological variables are inter-related, spurious correlations can occur. We test different approaches to investigate and account for this phenomenon. The results can provide new insight into mechanisms of vegetation-water-energy interactions and contribute to improve dynamic global vegetation models.</p>

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