Invariability, orbits and fuzzy attractors

In this paper, we present a generalization of a new systemic approach to abstract fuzzy systems. Using a fuzzy relations structure will retain the information provided by degrees of membership. In addition, to better suit the situation to be modelled, it is advisable to use T-norm or T-conorm distinct from the minimum and maximum, respectively. This gain in generality is due to the completeness of the work on a higher level of abstraction. You cannot always reproduce the results obtained previously, and also sometimes different definitions with different views are obtained. In any case this approach proves to be much more effective when modelling reality

Discrete fuzzy system orbits as a portfolio selection method

[EN] The purpose of this work is to approach the portfolio selection problem from a particular System Theory framework. The System will be formed by the set of public companies in the portfolio and a set of fuzzy relations on those companies. Starting with an equally split portfolio represented by a fuzzy set B, the orbit of B is computed for a particular period obtaining a portfolio to invest in the next period. We present an example ¿nding nine portfolios to invest in 9 months and we compare them with some optimal portfolios in the ef¿cient frontier given by the Modern Portfolio Theory and with some random generated portfolios. We ¿nd a better performance in returns for the portfolio based on the systemic method.Perez-Gonzaga, S.; Jordán Núñez, J.; Miró Martínez, P. (2017). Discrete fuzzy system orbits as a portfolio selection method. Operational Research (Online). doi:10.1007/s12351-017-0361-2SAgliardi E, Agliardi R (2011) Bond pricing under imprecise information. Oper Res 11(3):299–309Esteve-Calvo P, Lloret-Climent M (2006) Coverage, invariability and orbits by structural functions. Kybernetes 35(7/8):1236–1240Jegadeesh N, Titman S (1993) Returns to buying winners and selling losers: implications for stock market efficiency. J Finance 48(1):65–91Klement EP, Mesiar R, Pap E (2013) Triangular norms, vol 8. Springer, New YorkLloret-Climent M, Villacampa-Esteve Y, Us-Domenech JL (1998) System-linkage: structural functions and hierarchies. Cybern Syst 29(1):35–46Ma YH, Lin Y (1987) Some properties of linked time systems. Int J Gen Syst 13(2):125–134Markowitz H (1952) Portfolio selection. J Finance 7(1):77–91Perez-Gonzaga S, Lloret-Climent M, Nescolarde-Selva JA (2015) Invariability, orbits and fuzzy attractors. Int J Gen Syst 45(1):29–40Tiryaki F, Ahlatcioglu B (2009) Fuzzy portfolio selection using fuzzy analytic hierarchy process. Inf Sci 179(1):53–69Von Bertalanffy L (1968) General system theory: foundations, development, applications. George Braziller, New York, pp 40Zadeh LA (1962) From circuit theory to system theory. Proc IRE 50(5):856–86

Computer-Aided Diagnosis System of Fetal Hypoxia Incorporating Recurrence Plot With Convolutional Neural Network

Background: Electronic fetal monitoring (EFM) is widely applied as a routine diagnostic tool by clinicians using fetal heart rate (FHR) signals to prevent fetal hypoxia. However, visual interpretation of the FHR usually leads to significant inter-observer and intra-observer variability, and false positives become the main cause of unnecessary cesarean sections.Goal: The main aim of this study was to ensure a novel, consistent, robust, and effective model for fetal hypoxia detection.Methods: In this work, we proposed a novel computer-aided diagnosis (CAD) system integrated with an advanced deep learning (DL) algorithm. For a 1-dimensional preprocessed FHR signal, the 2-dimensional image was transformed using recurrence plot (RP), which is considered to greatly capture the non-linear characteristics. The ultimate image dataset was enriched by changing several parameters of the RP and was then used to feed the convolutional neural network (CNN). Compared to conventional machine learning (ML) methods, a CNN can self-learn useful features from the input data and does not perform complex manual feature engineering (i.e., feature extraction and selection).Results: Finally, according to the optimization experiment, the CNN model obtained the average performance using optimal configuration across 10-fold: accuracy = 98.69%, sensitivity = 99.29%, specificity = 98.10%, and area under the curve = 98.70%.Conclusion: To the best of our knowledge, this approached achieved better classification performance in predicting fetal hypoxia using FHR signals compared to the other state-of-the-art works.Significance: In summary, the satisfied result proved the effectiveness of our proposed CAD system for assisting obstetricians making objective and accurate medical decisions based on RP and powerful CNN algorithm

Dynamical systems : control and stability

Proceedings of the 13th Conference „Dynamical Systems - Theory and Applications" summarize 164 and the Springer Proceedings summarize 60 best papers of university teachers and students, researchers and engineers from whole the world. The papers were chosen by the International Scientific Committee from 315 papers submitted to the conference. The reader thus obtains an overview of the recent developments of dynamical systems and can study the most progressive tendencies in this field of science

Inferring ecosystem states and quantifying their resilience : linking theories to ecological data

The core of my thesis concerns addressing the ecosystem resilience in a data-driven manner. In this direction, I have tried to make a bridge between advanced mathematical models and existing ecological data. I could come up with some quantitative measures of resilience and applied them to some ecological field and experimental data. These measures are more exact compared with the classical measures mentioned by Holling. I show that Holling measures are just two extremes of the measure I introduced and they do not necessarily capture the notion of resilience in its real sense of the word. Furthermore, I could also address the resilience of low-resolution tropical satellite data across the tropics (South America, Africa, south east Asia and, Australia). Besides, my thesis also sheds more light on the concept of ‘alternative stable states’ which is an important concept in ecology. I argue that advanced ‘system reconstruction’ approaches should be applied first, from where one can better justify weather or not an ecosystem has alternative stable states. </p