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Hani Hagras - One of the best experts on this subject based on the ideXlab platform.
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Multiobjective Optimization and Comparison of NonSingleton Type-1 and Singleton Interval Type-2 Fuzzy Logic Systems
IEEE Transactions on Fuzzy Systems, 2013Co-Authors: Ana Belén Cara, Hani Hagras, Christian Wagner, Héctor Pomares, Ignacio RojasAbstract:Singleton interval type-2 fuzzy logic systems (FLSs) have been widely applied in several real-world applications, where it was shown that the Singleton interval type-2 FLSs outperform their Singleton type-1 counterparts in applications with high uncertainty levels. However, one of the main criticisms of Singleton interval type-2 FLSs is the fact that they outperform Singleton type-1 FLSs solely based on their use of extra degrees of freedom (extra parameters) and that type-1 FLSs with a sufficiently large number of parameters may provide the same performance as interval type-2 FLSs. In addition, most works on type-2 FLSs only compare their results with Singleton type-1 FLSs but fail to consider nonSingleton type-1 systems. In this paper, we aim to directly address and investigate this criticism. In order to do so, we will perform a comparative study between optimized Singleton type-1, nonSingleton type-1, and Singleton interval type-2 FLSs under the presence of noise. We will also present a multiobjective evolutionary algorithm (MOEA) for the optimization of Singleton type-1, nonSingleton type-1, and Singleton interval type-2 fuzzy systems for function approximation problems. The MOEA will aim to satisfy two objectives to maximize the accuracy of the FLS and minimize the number of rules in the FLS, thus improving its interpretability. Furthermore, we will present a methodology to obtain “optimal” consequents for the FLSs. Hence, this paper has two main contributions: First, it provides a common methodology to learn the three types of FLSs (i.e., Singleton type-1, nonSingleton type-1, and Singleton interval type-2 FLSs) from data samples. The second contribution is the creation of a common framework for the comparison of type-1 and type-2 FLSs that allows us to address the aforementioned criticism. We provide details of a series of experiments and include statistical analysis showing that the type-2 FLS is able to handle higher levels of noise than its nonSingleton and Singleton type-1 counterparts.
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Towards comparing adaptive type-2 input based non-Singleton type-2 FLS and non-Singleton FLSs employing Gaussian inputs
2012 IEEE International Conference on Fuzzy Systems, 2012Co-Authors: Nazanin Sahab, Hani HagrasAbstract:Fuzzy logic Systems (FLSs) are credited with providing very good performances which are able to handle the uncertainty and imprecision present in real-world environments and applications. Using type-2 FLSs can enable handling higher levels of uncertainty when compared to type-1 FLSs. The majority of the type-2 FLSs employ Singleton type-2 FLSs which handle the encountered input uncertainty through fuzzy sets representing the linguistic labels in the antecedent fuzzy sets. However, Singleton type-2 FLSs assume that the input signal is perfect and thus there is no provision for handling the uncertainties in the incoming input signals. Hence, there have been some efforts to investigate non-Singleton type-2 FLS. However, the papers that employed non-Singleton type-2 FLSs assumed that the fuzzy inputs are having a predefined shape (mostly Gaussian) which might not model the encountered uncertainty properly. In our previous works, we presented adaptive type-2 input based non-Singleton type-2 FLS which employs dynamic inputs which are not assuming any specific shape. We have shown how the adaptive type-2 input based non-Singleton type-2 FLS outperforms Singleton (type-1 and type-2) FLSs. In this paper, we will compare the adaptive type-2 input based non-Singleton type-2 FLS with other non-Singleton (type-1 and type-2) FLSs which employ Gaussian fuzzy inputs. We will present real-world robot experiments showing how the adaptive type-2 input based non-Singleton type-2 FLS outperforms the non-Singleton FLSs which employ Gaussian fuzzy inputs when large amounts of uncertainty are encountered.
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On comparing non-Singleton type-1 and Singleton type-2 fuzzy controllers for a nonlinear servo system
2011 IEEE Symposium on Advances in Type-2 Fuzzy Logic Systems (T2FUZZ), 2011Co-Authors: Ana Belén Cara, Christian Wagner, Héctor Pomares, Ignacio Rojas, Hani HagrasAbstract:Uncertainty handling is a major issue for the control of real-world systems. Traditional Singleton type-1 Fuzzy Logic Controllers (FLCs) with crisp inputs and precise fuzzy sets cannot fully cope with the high levels of uncertainties present in real world environments (e.g. sensor noise, environmental impacts, etc.). While non-Singleton type-1 fuzzy systems can provide an additional degree of freedom through non-Singleton fuzzification of the inputs, it is unclear how this capability relates to Singleton type-1 and specifically interval type-2 FLCs in terms of control performance (also because the application of non-Singleton type-1 FLCs is quite rare in the literature). In recent years interval type-2 FLCs employing type-2 fuzzy sets with a Footprint of Uncertainty (FOU) have become increasingly popular. This FOU provides an additional degree of freedom that can enable type-2 FLCs to handle the uncertainties associated with the inputs and the outputs of the FLCs. One of the main criticisms of Singleton type-2 FLCs is that they outperform (the usually Singleton-) type-1 FLCs because they - respectively their type-2 fuzzy sets, employ extra parameters, thus making improved performance an obvious result. In order to address this criticism, we have implemented a non-Singleton type-1 FLC which allows a more direct comparison between the non-Singleton type-1 FLC and Singleton interval type-2 FLC as the number of parameters for both controllers is very similar. The paper details the implementation details of the FLCs for the application of a nonlinear servo system and provides the experimental simulation results which were performed to study the effect of increasing levels of uncertainty (in the form of input noise) and the capability of the individual FLCs to cope with them. We conclude by providing our interpretation of the results and highlighting the essential differences in the uncertainty handling between the (non-) Singleton type-1 and Singleton interval type-2 FLCs.
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T2FUZZ - On comparing non-Singleton type-1 and Singleton type-2 fuzzy controllers for a nonlinear servo system
2011 IEEE Symposium on Advances in Type-2 Fuzzy Logic Systems (T2FUZZ), 2011Co-Authors: Ana Belén Cara, Christian Wagner, Héctor Pomares, Ignacio Rojas, Hani HagrasAbstract:Uncertainty handling is a major issue for the control of real-world systems. Traditional Singleton type-1 Fuzzy Logic Controllers (FLCs) with crisp inputs and precise fuzzy sets cannot fully cope with the high levels of uncertainties present in real world environments (e.g. sensor noise, environmental impacts, etc.). While non-Singleton type-1 fuzzy systems can provide an additional degree of freedom through non-Singleton fuzzification of the inputs, it is unclear how this capability relates to Singleton type-1 and specifically interval type-2 FLCs in terms of control performance (also because the application of non-Singleton type-1 FLCs is quite rare in the literature). In recent years interval type-2 FLCs employing type-2 fuzzy sets with a Footprint of Uncertainty (FOU) have become increasingly popular. This FOU provides an additional degree of freedom that can enable type-2 FLCs to handle the uncertainties associated with the inputs and the outputs of the FLCs. One of the main criticisms of Singleton type-2 FLCs is that they outperform (the usually Singleton-) type-1 FLCs because they - respectively their type-2 fuzzy sets, employ extra parameters, thus making improved performance an obvious result. In order to address this criticism, we have implemented a non-Singleton type-1 FLC which allows a more direct comparison between the non-Singleton type-1 FLC and Singleton interval type-2 FLC as the number of parameters for both controllers is very similar. The paper details the implementation details of the FLCs for the application of a nonlinear servo system and provides the experimental simulation results which were performed to study the effect of increasing levels of uncertainty (in the form of input noise) and the capability of the individual FLCs to cope with them. We conclude by providing our interpretation of the results and highlighting the essential differences in the uncertainty handling between the (non-) Singleton type-1 and Singleton interval type-2 FLCs.
I Blickstein - One of the best experts on this subject based on the ideXlab platform.
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Perinatal outcomes in Singleton and twin pregnancies following first-trimester bleeding
Journal of Perinatology, 2014Co-Authors: M Lucovnik, I Verdenik, I BlicksteinAbstract:Objective: To investigate associations between first-trimester bleeding and perinatal outcomes. Study design: Registry-based survey of the period 2002 through 2010. Pregnancies with versus without first-trimester bleeding were compared using Student’s t- and χ ^2-test. Multivariable logistic regression was used to control for potential confounders. Result: 9924 Singleton and 275 twin pregnancies with first-trimester bleeding, and 160 099 Singleton and 2710 twin pregnancies without bleeding were included. Bleeding increased the risk of preterm birth in Singletons (odds ratio 1.48; 95% confidence interval 1.38–1.60). Risks were also increased for preterm premature rupture of membranes, abruption, previa, stillbirth and congenital anomalies, with a reduced risk of preeclampsia. The differences remained significant after adjustment for confounders. In twin pregnancies, bleeding was not significantly associated with prematurity (odds ratio 1.04; 95% confidence interval 0.81–1.34), nor with other outcomes. Conclusion: In Singletons, but not in twins, the risk of perinatal complications is significantly increased after first-trimester bleeding.
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plurality dependent risk of severe intraventricular hemorrhage among very low birth weight infants and antepartum corticosteroid treatment
American Journal of Obstetrics and Gynecology, 2006Co-Authors: I Blickstein, Brian Reichman, Ayala Lusky, Eric S ShinwellAbstract:Objective This study was undertaken to compare the effect of antenatal corticosteroid therapy on the risk for severe intraventricular hemorrhage (IVH grade III-IV) in preterm Singleton and multiple very low birth weight (VLBW) infants. Study design The occurrence of severe IVH was recorded in 5022 Singleton, 2032 twin, and 582 triplet infants, delivered at 24 to 32 weeks' gestation, registered in the Israeli National VLBW infant database. Antenatal corticosteroid therapy was defined as complete, partial, or none. Results The incidence of IVH grade III-IV ranged from 6.8% among Singletons receiving complete course to 29.3% in triplets without antenatal corticosteroid treatment. Complete treatment significantly reduced the incidence of IVH in all plurality groups. The adjusted risk for IVH among multiple infants who received a complete course compared with Singletons was not significantly different, odds ratio (OR) 1.3, 95% CI 1.0-1.7 for twins and OR 1.5, 95% CI 0.9-2.3 for triplets. Conclusion Complete course of antenatal corticosteroid therapy was independently associated with decreased risk for severe IVH in Singleton and in multiple preterm VLBW infants.
Ignacio Rojas - One of the best experts on this subject based on the ideXlab platform.
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Multiobjective Optimization and Comparison of NonSingleton Type-1 and Singleton Interval Type-2 Fuzzy Logic Systems
IEEE Transactions on Fuzzy Systems, 2013Co-Authors: Ana Belén Cara, Hani Hagras, Christian Wagner, Héctor Pomares, Ignacio RojasAbstract:Singleton interval type-2 fuzzy logic systems (FLSs) have been widely applied in several real-world applications, where it was shown that the Singleton interval type-2 FLSs outperform their Singleton type-1 counterparts in applications with high uncertainty levels. However, one of the main criticisms of Singleton interval type-2 FLSs is the fact that they outperform Singleton type-1 FLSs solely based on their use of extra degrees of freedom (extra parameters) and that type-1 FLSs with a sufficiently large number of parameters may provide the same performance as interval type-2 FLSs. In addition, most works on type-2 FLSs only compare their results with Singleton type-1 FLSs but fail to consider nonSingleton type-1 systems. In this paper, we aim to directly address and investigate this criticism. In order to do so, we will perform a comparative study between optimized Singleton type-1, nonSingleton type-1, and Singleton interval type-2 FLSs under the presence of noise. We will also present a multiobjective evolutionary algorithm (MOEA) for the optimization of Singleton type-1, nonSingleton type-1, and Singleton interval type-2 fuzzy systems for function approximation problems. The MOEA will aim to satisfy two objectives to maximize the accuracy of the FLS and minimize the number of rules in the FLS, thus improving its interpretability. Furthermore, we will present a methodology to obtain “optimal” consequents for the FLSs. Hence, this paper has two main contributions: First, it provides a common methodology to learn the three types of FLSs (i.e., Singleton type-1, nonSingleton type-1, and Singleton interval type-2 FLSs) from data samples. The second contribution is the creation of a common framework for the comparison of type-1 and type-2 FLSs that allows us to address the aforementioned criticism. We provide details of a series of experiments and include statistical analysis showing that the type-2 FLS is able to handle higher levels of noise than its nonSingleton and Singleton type-1 counterparts.
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On comparing non-Singleton type-1 and Singleton type-2 fuzzy controllers for a nonlinear servo system
2011 IEEE Symposium on Advances in Type-2 Fuzzy Logic Systems (T2FUZZ), 2011Co-Authors: Ana Belén Cara, Christian Wagner, Héctor Pomares, Ignacio Rojas, Hani HagrasAbstract:Uncertainty handling is a major issue for the control of real-world systems. Traditional Singleton type-1 Fuzzy Logic Controllers (FLCs) with crisp inputs and precise fuzzy sets cannot fully cope with the high levels of uncertainties present in real world environments (e.g. sensor noise, environmental impacts, etc.). While non-Singleton type-1 fuzzy systems can provide an additional degree of freedom through non-Singleton fuzzification of the inputs, it is unclear how this capability relates to Singleton type-1 and specifically interval type-2 FLCs in terms of control performance (also because the application of non-Singleton type-1 FLCs is quite rare in the literature). In recent years interval type-2 FLCs employing type-2 fuzzy sets with a Footprint of Uncertainty (FOU) have become increasingly popular. This FOU provides an additional degree of freedom that can enable type-2 FLCs to handle the uncertainties associated with the inputs and the outputs of the FLCs. One of the main criticisms of Singleton type-2 FLCs is that they outperform (the usually Singleton-) type-1 FLCs because they - respectively their type-2 fuzzy sets, employ extra parameters, thus making improved performance an obvious result. In order to address this criticism, we have implemented a non-Singleton type-1 FLC which allows a more direct comparison between the non-Singleton type-1 FLC and Singleton interval type-2 FLC as the number of parameters for both controllers is very similar. The paper details the implementation details of the FLCs for the application of a nonlinear servo system and provides the experimental simulation results which were performed to study the effect of increasing levels of uncertainty (in the form of input noise) and the capability of the individual FLCs to cope with them. We conclude by providing our interpretation of the results and highlighting the essential differences in the uncertainty handling between the (non-) Singleton type-1 and Singleton interval type-2 FLCs.
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T2FUZZ - On comparing non-Singleton type-1 and Singleton type-2 fuzzy controllers for a nonlinear servo system
2011 IEEE Symposium on Advances in Type-2 Fuzzy Logic Systems (T2FUZZ), 2011Co-Authors: Ana Belén Cara, Christian Wagner, Héctor Pomares, Ignacio Rojas, Hani HagrasAbstract:Uncertainty handling is a major issue for the control of real-world systems. Traditional Singleton type-1 Fuzzy Logic Controllers (FLCs) with crisp inputs and precise fuzzy sets cannot fully cope with the high levels of uncertainties present in real world environments (e.g. sensor noise, environmental impacts, etc.). While non-Singleton type-1 fuzzy systems can provide an additional degree of freedom through non-Singleton fuzzification of the inputs, it is unclear how this capability relates to Singleton type-1 and specifically interval type-2 FLCs in terms of control performance (also because the application of non-Singleton type-1 FLCs is quite rare in the literature). In recent years interval type-2 FLCs employing type-2 fuzzy sets with a Footprint of Uncertainty (FOU) have become increasingly popular. This FOU provides an additional degree of freedom that can enable type-2 FLCs to handle the uncertainties associated with the inputs and the outputs of the FLCs. One of the main criticisms of Singleton type-2 FLCs is that they outperform (the usually Singleton-) type-1 FLCs because they - respectively their type-2 fuzzy sets, employ extra parameters, thus making improved performance an obvious result. In order to address this criticism, we have implemented a non-Singleton type-1 FLC which allows a more direct comparison between the non-Singleton type-1 FLC and Singleton interval type-2 FLC as the number of parameters for both controllers is very similar. The paper details the implementation details of the FLCs for the application of a nonlinear servo system and provides the experimental simulation results which were performed to study the effect of increasing levels of uncertainty (in the form of input noise) and the capability of the individual FLCs to cope with them. We conclude by providing our interpretation of the results and highlighting the essential differences in the uncertainty handling between the (non-) Singleton type-1 and Singleton interval type-2 FLCs.
Eric S Shinwell - One of the best experts on this subject based on the ideXlab platform.
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plurality dependent risk of severe intraventricular hemorrhage among very low birth weight infants and antepartum corticosteroid treatment
American Journal of Obstetrics and Gynecology, 2006Co-Authors: I Blickstein, Brian Reichman, Ayala Lusky, Eric S ShinwellAbstract:Objective This study was undertaken to compare the effect of antenatal corticosteroid therapy on the risk for severe intraventricular hemorrhage (IVH grade III-IV) in preterm Singleton and multiple very low birth weight (VLBW) infants. Study design The occurrence of severe IVH was recorded in 5022 Singleton, 2032 twin, and 582 triplet infants, delivered at 24 to 32 weeks' gestation, registered in the Israeli National VLBW infant database. Antenatal corticosteroid therapy was defined as complete, partial, or none. Results The incidence of IVH grade III-IV ranged from 6.8% among Singletons receiving complete course to 29.3% in triplets without antenatal corticosteroid treatment. Complete treatment significantly reduced the incidence of IVH in all plurality groups. The adjusted risk for IVH among multiple infants who received a complete course compared with Singletons was not significantly different, odds ratio (OR) 1.3, 95% CI 1.0-1.7 for twins and OR 1.5, 95% CI 0.9-2.3 for triplets. Conclusion Complete course of antenatal corticosteroid therapy was independently associated with decreased risk for severe IVH in Singleton and in multiple preterm VLBW infants.
Christina Bergh - One of the best experts on this subject based on the ideXlab platform.
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high risks of maternal and perinatal complications in Singletons born after oocyte donation
Acta Obstetricia et Gynecologica Scandinavica, 2016Co-Authors: Sarah Nejdet, Christina Bergh, Karin Kallen, Ullabritt Wennerholm, Ann ThurinkjellbergAbstract:INTRODUCTION: Previous studies have shown an increased risk of obstetric complications in pregnancies after oocyte donation (OD). The present study includes all Singletons born after OD during 10 years in Sweden.MATERIAL AND METHODS: A retrospective cohort study that included data from all Swedish in vitro fertilization (IVF) clinics between 2003 and 2012 was performed. Data were cross-linked with the Swedish Medical Birth Registry. The study included 388 OD Singletons, 26,696 IVF/ICSI Singletons and 999,804 spontaneously conceived (SC) Singletons. Adjusted odds ratio (AOR) was calculated with adjustment for relevant confounders.RESULTS: Singleton OD pregnancies had a significantly increased risk of preeclampsia compared to IVF (AOR 3.05; 95% CI 2.23-4.16) and SC (AOR 2.84; 95% CI 2.10-3.84), increased risk of postpartum hemorrhage (>1000 ml) compared to IVF (AOR 2.66; 95% CI 2.04-3.49) and SC (AOR 2.87; 95% CI 2.20-3.71), higher risk of preterm birth (<37) compared to IVF (AOR 1.79; 95% CI 1.30-2.46) and SC (AOR 1.58; 95% CI 1.15-2.16) and low birth weight (<2500 g) compared to IVF (AOR 1.67; 95% CI 1.15-2.42) and SC (AOR 1.46; 95% CI 1.01-2.11). The rate of large for gestational age was significantly increased in Singletons born after OD with frozen cycles compared to fresh cycles (odds ratio 5.29, 95% CI 1.30-21.54).CONCLUSIONS: Singleton pregnancies conceived after OD are associated with increased maternal and perinatal risks compared to IVF/ICSI pregnancies using the woman's own oocytes and with SC. This article is protected by copyright. All rights reserved. (Less)
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neonatal and maternal outcomes comparing women undergoing two in vitro fertilization ivf Singleton pregnancies and women undergoing one ivf twin pregnancy
Fertility and Sterility, 2013Co-Authors: Antonina Sazonova, Ullabritt Wennerholm, Karin Kallen, Ann Thurinkjellberg, Christina BerghAbstract:Objective To compare outcomes for women undergoing two in vitro fertilization (IVF) pregnancies with Singletons and women undergoing one IVF twin pregnancy. The concept of single-embryo transfer in IVF has reduced the risks of both maternal and neonatal complications, but there is still a discussion of whether or not twins are a desired outcome of IVF. Design Registry study. Setting Not applicable. Patient(s) All reported twins after IVF with double-embryo transfer (n = 1,982) and their mothers (n = 991) and all mothers (n = 921) who gave birth to two IVF Singletons (n = 1,842). Intervention(s) None. Main Outcome Measure(s) Maternal and neonatal outcomes including severe neonatal morbidity. Result(s) Preterm birth, very preterm birth, low birth weight, very low birth weight, and small for gestational age were dramatically increased for IVF twins compared with two IVF Singletons with the same mother, with adjusted odds ratios from 4 to 16. Significantly higher rates of respiratory complications, sepsis, and jaundice were detected among the IVF twins. Significantly higher rates of preeclampsia, preterm premature rupture of the membranes, and cesarean section were observed for IVF twin pregnancies. Conclusion(s) The neonatal and maternal outcomes were dramatically better for women undergoing two IVF Singleton pregnancies compared with one IVF twin pregnancy after double-embryo transfer. These results support single-embryo transfer to minimize the risks associated with twin pregnancies.
