Search results for "Complexity"
showing 10 items of 1094 documents
A multi-agent system reinforcement learning based optimal power flow for islanded microgrids
2016
In this paper, a distributed intelligence algorithm is used to manage the optimal power flow problem in islanded microgrids. The methodology provides a suboptimal solution although the error is limited to a few percent as compared to a centralized approach. The solution algorithm is multi-agent based. According to the method, couples of agents communicate with each other only if the buses where they are located are electrically connected. The overall prizing system required for learning uses a feedback from an approximated model of the network. Based on the latter, a distributed reiforcement learning algorithm is implemented to minimize the joule losses while meeting operational constraints…
Exploring Environmental and Entrepreneurial Antecedents of Social Performance in Spanish Sports Clubs: A Symmetric and Asymmetric Approach
2020
The social function of non-profit sports clubs is undeniable, so analyzing the factors that influence their performance is vital. The aim of this study is to understand the influence of entrepreneurial factors (entrepreneurial orientation) and environmental factors (dynamism, hostility and complexity) on social performance using a symmetrical (Hierarchical regression model) and asymmetrical (qualitative comparative analysis) approach. The social performance of this particular type of organization is of great importance in an environment where sustainability from a social point of view is increasingly on the agenda of governments, organizations and society in general. A total of 209 Spanish …
Ambidexterity – A New Paradigm for Organizations Facing Complexity
2019
Abstract Complexity is rapidly and inexorably leading the global economy towards new configurations and new dynamics; within this (ever fluid and unstable) framework, the strategic dualities that govern organizations and shape their strategic choices are not only multiplying but also interacting and generating unprecedented challenges: new pairs of (apparent) paradoxes occur, sophisticated interdependencies take place amongst them, and therefore new approaches in search for strategic solutions are imperatively asked. Against this background, the main goal of the paper is to suggest a paradigm of organizational ambidexterity – which gradually integrates various angles and valences into parti…
Changes in fish communities due to benthic habitat shifts under ocean acidification conditions
2020
Ocean acidification will likely change the structure and function of coastal marine ecosystems over coming decades. Volcanic carbon dioxide seeps generate dissolved CO2 and pH gradients that provide realistic insights into the direction and magnitude of these changes. Here, we used fish and benthic community surveys to assess the spatio-temporal dynamics of fish community properties off CO2 seeps in Japan. Adding to previous evidence from ocean acidification ecosystem studies conducted elsewhere, our findings documented shifts from calcified to non-calcified habitats with reduced benthic complexity. In addition, we found that such habitat transition led to decreased diversity of associated …
Foaming in membrane bioreactors: Identification of the causes
2012
Membrane bioreactors (MBRs) represent by now a well established alternative for wastewater treatment. Their increasing development is undoubtedly related to the several advantages that such technology is able to guarantee. Nevertheless, this technology is not exempt from operational problems; among them the foaming still represents an "open challenge" of the MBR field, due to the high complexity of phenomenon. Unfortunately, very little work has been done on the foaming in MBRs and further studies are required. Actually, there is not a distinct difference between conventional activated system and MBR: the main difference is that the MBR plants can retain most Extracellular Polymeric Substan…
Toward a New Plant-Wide Experimental and Modeling Approach for Reduction of Greenhouse Gas Emission from Wastewater Treatment Plants
2019
Mechanisms causing greenhouse gas (GHG) emission in wastewater treatment plants are of great interest among researchers, encouraging the development of new methods for wastewater management. Wastewater treatment plants (WWTPs) emit three major greenhouse gases during the treatment processes: CO2, CH4, and N2O. Additional amounts of CO2 and CH4 are produced during energy consumption, which can be considered an indirect source of GHGs. Recently, several efforts have been undertaken to assess GHGs from WWTPs, with particular attention paid to the N2O assessment due to its high warming potential (300 times stronger than CO2). This study proposes an integrated model platform for WWTP simulation,…
CUDA-Accelerated Alignment of Subsequences in Streamed Time Series Data
2014
Euclidean Distance (ED) and Dynamic Time Warping (DTW) are cornerstones in the field of time series data mining. Many high-level algorithms like kNN-classification, clustering or anomaly detection make excessive use of these distance measures as subroutines. Furthermore, the vast growth of recorded data produced by automated monitoring systems or integrated sensors establishes the need for efficient implementations. In this paper, we introduce linear memory parallelization schemes for the alignment of a given query Q in a stream of time series data S for both ED and DTW using CUDA-enabled accelerators. The ED parallelization features a log-linear calculation scheme in contrast to the naive …
On the complexity of the Saccharomyces bayanus taxon: Hybridization and potential hybrid speciation
2014
Although the genus Saccharomyces has been thoroughly studied, some species in the genus has not yet been accurately resolved; an example is S. bayanus, a taxon that includes genetically diverse lineages of pure and hybrid strains. This diversity makes the assignation and classification of strains belonging to this species unclear and controversial. They have been subdivided by some authors into two varieties (bayanus and uvarum), which have been raised to the species level by others. In this work, we evaluate the complexity of 46 different strains included in the S. bayanus taxon by means of PCR-RFLP analysis and by sequencing of 34 gene regions and one mitochondrial gene. Using the sequenc…
Efficiency improvement of DC* through a Genetic Guidance
2017
DC∗ is a method for generating interpretable fuzzy information granules from pre-classified data. It is based on the subsequent application of LVQ1 for data compression and an ad-hoc procedure based on A∗ to represent data with the minimum number of fuzzy information granules satisfying some interpretability constraints. While being efficient in tackling several problems, the A∗ procedure included in DC∗ may happen to require a long computation time because the A∗ algorithm has exponential time complexity in the worst case. In this paper, we approach the problem of driving the search process of A∗ by suggesting a close-to-optimal solution that is produced through a Genetic Algorithm (GA). E…
On the effectiveness of Finite Element simulation of orthogonal cutting with particular reference to temperature prediction
2007
Abstract Finite Element simulation of orthogonal cutting is nowadays assuming a large relevance; in fact a very large number of papers may be found out in technical literature on this topic. In recent years, numerical simulation was performed to investigate various phenomena such as chip segmentation, force prediction and tool wear. On the other hand, some drawbacks have to be highlighted; due to the geometrical and computational complexity of the updated-Lagrangian formulation mostly used in FE codes, a cutting time of only a few milliseconds can be effectively simulated. Therefore, steady-state thermal conditions are not reached and the simulation of the thermal phenomenon may be ineffect…