138 research outputs found
Collapsibility Prediction of Stabilized Soil with Styrene-Butadiene Rubber Polymer Using ANFIS
Collapsible soils are among the problematic soils in nature that, due to moisture content increasing and under the same stress, show a high rate of decrease in volume. This volume reduction leads to loss of soil structure and ultimately to significant subsidence. Such soils in many parts of the world, including the Kerman province of Iran, necessitate researches regarding the collapsible soils\u27 behavior and characteristics. This study aims to investigate the effect of butadiene rubber on the stabilization of collapsible soils. The tested fine-grained soils that have been sampled from two different sites were stabilized through injecting different percentages of butadiene (the number of experiments was 84). The ASTM D5333 Double-Consolidation Method was applied to examine the stabilized soils on intact soil samples. The results show that the penetrations of butadiene rubber and the formation of butadiene rubber columns have led to a reduction in soil collapse. Considering the development of intelligent systems using the prediction behavior of stabilized collapsible soils, the adaptive neural-fuzzy inference system (ANFIS) model was used to predict the degree of collapsibility of soil samples stabilized by injection of Styrene Butadiene Rubber
Preventive Conservation and Restoration Monitoring of Heritage Buildings Based on Fuzzy Logic
This article discusses the usability of the Art-Risk 3.0 software for research on the conservation of
heritage buildings. It is a new and free software based on fuzzy logic, which enables the assessment
of preventive conservation and surveillance of the restoration of heritage buildings over a period of
time. This artificial intelligence-based tool considers the vulnerability of buildings, their environ ments, and their management to evaluate the necessity of their restoration or preventive con servation. To validate the Art-Risk 3.0, 500 theoretical case studies were analyzed, and a 14th century Mudejar-Gothic-style Church in Seville, Spain was studied both before and after its restora tion to identify post-restoration changes. This proof of concept demonstrates the capability of the
Art-Risk 3.0 software to analyze environmental impacts on the vulnerability, risk, and functional
service life of buildings, and assess the effectiveness of restoration activities. Additionally, this
software identifies the most problematic factors and the necessity of restoration.Ministerio de Economía y Competitividad BIA2015- 64878-R (RETOS)Ministerio de Ciencia e Innovación PID2019-107257RB-I00 (FENIX)Ministerio de Ciencia, Innovación y Universidades EQC2019-005780-P (Ambulab-LAB)Junta de Andalucía PYC20 RE 034 UPO RESILIENT-TOURISMMinisterio de Ciencia e Innovación PTA2019-01688
Integration of the Wang & Mendel algorithm into the application of Fuzzy expert systems to intelligent clinical decision support systems
The use of intelligent systems in clinical diagnostics has evolved, integrating statistical learning and knowledge-based representation models. Two recent works propose the identification of risk factors for the diagnosis of obstructive sleep apnea (OSA). The first uses statistical learning to identify indicators associated with different levels of the apnea-hypopnea index (AHI). The second paper combines statistical and symbolic inference approaches to obtain risk indicators (Statistical Risk and Symbolic Risk) for a given AHI level. Based on this, in this paper we propose a new intelligent system that considers different AHI levels and generates risk pairs for each level. A learning-based model generates Statistical Risks based on objective patient data, while a cascade of fuzzy expert systems determines a Symbolic Risk using symptom data from patient interviews. The aggregation of risk pairs at each level involves a fuzzy expert system with automatically generated fuzzy rules using the Wang-Mendel algorithm. This aggregation produces an Apnea Risk indicator for each AHI level, allowing discrimination between OSA and non-OSA cases, along with appropriate recommendations. This approach improves variability, usefulness, and interpretability, increasing the reliability of the system. Initial tests on data from 4400 patients yielded AUC values of 0.74–0.88, demonstrating the potential benefits of the proposed intelligent system architecture.Xunta de Galicia | Ref. ED481A-2020/03
Layer of protection analysis applied to ammonia refrigeration systems
Ammonia refrigeration systems are widely used in industry. Demand of these
systems is expected to increase due to the advantages of ammonia as refrigerant and
because ammonia is considered a green refrigerant. Therefore, it is important to evaluate
the risks in existing and future ammonia refrigeration systems to ensure their safety.
LOPA (Layer of Protection Analysis) is one of the best ways to estimate the risk.
It provides quantified risk results with less effort and time than other methods. LOPA
analyses one cause-consequence scenario per time. It requires failure data and PFD
(Probability of Failure on Demand) of the independent protection layers available to
prevent the scenario. Complete application of LOPA requires the estimation of the
severity of the consequences and the mitigated frequency of the initiating event for risk
calculations.
Especially in existing ammonia refrigeration systems, information to develop
LOPA is sometimes scarce and uncertain. In these cases, the analysis relies on expert
opinion to determine the values of the variables required for risk estimation. Fuzzy
Logic has demonstrated to be useful in this situation allowing the construction of expert
systems.
Based on fuzzy logic, the LOPA method was adapted to represent the knowledge
available in standards and good industry practices for ammonia refrigeration. Fuzzy
inference systems were developed for severity and risk calculation. Severity fuzzy inference system uses the number of life threatening injuries or deaths, number of
injuries and type of medical attention required to calculate the severity risk index.
Frequency of the mitigated scenario is calculated using generic data for the initiating
event frequency and PFD of the independent protection layers. Finally, the risk fuzzy
inference system uses the frequency and severity values obtained to determine the risk of
the scenario.
The methodology was applied to four scenarios. Risk indexes were calculated
and compared with the traditional approach and risk decisions were made.
In conclusion, the fuzzy logic LOPA method provides good approximations of
the risk for ammonia refrigeration systems. The technique can be useful for risk
assessment of existing ammonia refrigeration systems
Biological investigation and predictive modelling of foaming in anaerobic digester
Anaerobic digestion (AD) of waste has been identified as a leading technology for greener renewable energy generation as an alternative to fossil fuel. AD will reduce waste through biochemical processes, converting it to biogas which could be used as a source of renewable energy and the residue bio-solids utilised in enriching the soil. A problem with AD though is with its foaming and the associated biogas loss. Tackling this problem effectively requires identifying and effectively controlling factors that trigger and promote foaming. In this research, laboratory experiments were initially carried out to differentiate foaming causal and exacerbating factors. Then the impact of the identified causal factors (organic loading rate-OLR and volatile fatty acid-VFA) on foaming occurrence were monitored and recorded. Further analysis of foaming and nonfoaming sludge samples by metabolomics techniques confirmed that the OLR and VFA are the prime causes of foaming occurrence in AD. In addition, the metagenomics analysis showed that the phylum bacteroidetes and proteobacteria were found to be predominant with a higher relative abundance of 30% and 29% respectively while the phylum actinobacteria representing the most prominent filamentous foam causing bacteria such as Norcadia amarae and Microthrix Parvicella had a very low and consistent relative abundance of 0.9% indicating that the foaming occurrence in the AD studied was not triggered by the presence of filamentous bacteria. Consequently, data driven models to predict foam formation were developed based on experimental data with inputs (OLR and VFA in the feed) and output (foaming occurrence). The models were extensively validated and assessed based on the mean squared error (MSE), root mean squared error (RMSE), R2 and mean absolute error (MAE). Levenberg Marquadt neural network model proved to be the best model for foaming prediction in AD, with RMSE = 5.49, MSE = 30.19 and R2 = 0.9435. The significance of this study is the development of a parsimonious and effective modelling tool that enable AD operators to proactively avert foaming occurrence, as the two model input variables (OLR and VFA) can be easily adjustable through simple programmable logic controller
The posterity of Zadeh's 50-year-old paper: A retrospective in 101 Easy Pieces – and a Few More
International audienceThis article was commissioned by the 22nd IEEE International Conference of Fuzzy Systems (FUZZ-IEEE) to celebrate the 50th Anniversary of Lotfi Zadeh's seminal 1965 paper on fuzzy sets. In addition to Lotfi's original paper, this note itemizes 100 citations of books and papers deemed “important (significant, seminal, etc.)” by 20 of the 21 living IEEE CIS Fuzzy Systems pioneers. Each of the 20 contributors supplied 5 citations, and Lotfi's paper makes the overall list a tidy 101, as in “Fuzzy Sets 101”. This note is not a survey in any real sense of the word, but the contributors did offer short remarks to indicate the reason for inclusion (e.g., historical, topical, seminal, etc.) of each citation. Citation statistics are easy to find and notoriously erroneous, so we refrain from reporting them - almost. The exception is that according to Google scholar on April 9, 2015, Lotfi's 1965 paper has been cited 55,479 times
A comparison of machine learning regression models for critical bus voltage and load mapping with regards to max reactive power in pv buses.
The aim of this master thesis is to compare voltage and system loading mapping capabilities
of a variety of regression algorithms, such as Adaptive Network based Fuzzy Inference
System (ANFIS), Artificial Neural Networks (ANN), K-Nearest Neighbors (KNN), Support
Vector Regression (SVR), and Decision Tree (DT). A voltage sensitivity matrix is
generated from the power flow Jacobian matrix for a loading scenario near the unstable
point. Principal Component Analysis (PCA) is used to separate the system, close
to the critical point, in order to group the buses into coherent voltage controlling areas.
For different reactive power injection scenarios, we have different bus voltages that can
be mapped by the aforementioned regression algorithms. The algorithms are trained with
limited amounts of data, in order to establish a fair comparison between them. The present
work shows that ANFIS and KNN have a better performance in critical voltage and load
prediction when compared to the rest. The academic IEEE 14 and 118 bus systems are
employed with all its limits considered, so the results may be reproduced.Agência 1O objetivo desta dissertação de mestrado é comparar as capacidades de mapeamento de
tensão e carregamento do sistema para uma variedade de algoritmos de regressão, como
Adaptive Neuro-Fuzzy Inference System (ANFIS), Artificial Neural Networks (ANN), KNearest
Neighbors (KNN), Support Vector Regression (SVR) e Decition Tree (DT). Uma
matriz de sensibilidade à tensão é gerada a partir da matriz Jacobiana do fluxo de potência
para um cenário de carregamento próximo ao ponto instável. A Análise de Componentes
Principais (PCA) é usada para separar o sistema, próximo ao ponto crítico, a fim de
agrupar os barramentos em áreas de controle de tensão coerentes. Para diferentes cenários
de injeção de potência reativa, temos diferentes tensões de barramento que podem ser
mapeadas pelos algoritmos de regressão mencionados acima. Os algoritmos são treinados
com quantidades limitadas de dados, a fim de estabelecer uma comparação justa entre eles.
O presente trabalho mostra que ANFIS e KNN têm um melhor desempenho em tensão
crítica e previsão de carga quando comparados aos demais. Os sistemas de barramento
acadêmico IEEE 14 e 118 são empregados com todos os seus limites considerados, portanto
os resultados podem ser reproduzidos
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