376 research outputs found
Evolutionary synthesis and control of chaotic systems
This research deals with the synthesis and control of chaos by means of evolutionary algorithms. The main aim of this work is to show that evolutionary algorithms are capable of synthesis of new chaotic system and optimization of its control and to show a new approach of solving this problem and constructing new cost functions operating in "blackbox mode" without previous exact mathematical analysis of the system, thus without knowledge of stabilizing of the target state. Three different cost functions are presented and tested. The optimizations were achieved in several ways, each one for another desired periodic orbit. The evolutionary algorithm, Self-Organizing Migrating Algorithm (SOMA) was used in its four versions. For each version, repeated simulations were conducted to outline the effectiveness and robustness of used method and cost function. Presented results lend weight to the argument, that proposed cost functions give satisfactory results
Analytic Predictive of Hepatitis using The Regression Logic Algorithm
Hepatitis is an inflammation of the liver which is
one of the diseases that affects the health of millions of people
in the world of all ages. Predicting the outcome of this disease
can be said to be quite challenging, where the main challenge
for public health care services itself is due to a limited clinical
diagnosis at an early stage. So by utilizing machine learning
techniques on existing data, namely by concluding diagnostic
rules to see trends in hepatitis patient data and see what factors are affecting patients with hepatitis, can make the diagnosis process more reliable to improve their health care. The approach that can be used to carry out this prediction process is a regression technique. The regression itself provides a relationship between the independent variable and the dependent variable. By using the hepatitis disease dataset from UCI Machine Learning, this study applies a logistic regression model that provides analysis results with an accuracy rate of 83.33
Evolutionary polymorphic neural networks in chemical engineering modeling
Evolutionary Polymorphic Neural Network (EPNN) is a novel approach to modeling chemical, biochemical and physical processes. This approach has its basis in modern artificial intelligence, especially neural networks and evolutionary computing. EPNN can perform networked symbolic regressions for input-output data, while providing information about both the structure and complexity of a process during its own evolution.
In this work three different processes are modeled: 1. A dynamic neutralization process. 2. An aqueous two-phase system. 3. Reduction of a biodegradation model. In all three cases, EPNN shows better or at least equal performances over published data than traditional thermodynamics /transport or neural network models. Furthermore, in those cases where traditional modeling parameters are difficult to determine, EPNN can be used as an auxiliary tool to produce equivalent empirical formulae for the target process. Feedback links in EPNN network can be formed through training (evolution) to perform multiple steps ahead predictions for dynamic nonlinear systems. Unlike existing applications combining neural networks and genetic algorithms, symbolic formulae can be extracted from EPNN modeling results for further theoretical analysis and process optimization. EPNN system can also be used for data prediction tuning. In which case, only a minimum number of initial system conditions need to be adjusted. Therefore, the network structure of EPNN is more flexible and adaptable than traditional neural networks. Due to the polymorphic and evolutionary nature of the EPNN system, the initially randomized values of constants in EPNN networks will converge to the same or similar forms of functions in separate runs until the training process ends. The EPNN system is not sensitive to differences in initial values of the EPNN population. However, if there exists significant larger noise in one or more data sets in the whole data composition, the EPNN system will probably fail to converge to a satisfactory level of prediction on these data sets. EPNN networks with a relatively small number of neurons can achieve similar or better performance than both traditional thermodynamic and neural network models.
The developed EPNN approach provides alternative methods for efficiently modeling complex, dynamic or steady-state chemical processes. EPNN is capable of producing symbolic empirical formulae for chemical processes, regardless of whether or not traditional thermodynamic models are available or can be applied. The EPNN approach does overcome some of the limitations of traditional thermodynamic /transport models and traditional neural network models
Classification Under Misspecification: Halfspaces, Generalized Linear Models, and Connections to Evolvability
In this paper we revisit some classic problems on classification under
misspecification. In particular, we study the problem of learning halfspaces
under Massart noise with rate . In a recent work, Diakonikolas,
Goulekakis, and Tzamos resolved a long-standing problem by giving the first
efficient algorithm for learning to accuracy for any
. However, their algorithm outputs a complicated hypothesis,
which partitions space into regions. Here we give a
much simpler algorithm and in the process resolve a number of outstanding open
questions:
(1) We give the first proper learner for Massart halfspaces that achieves
. We also give improved bounds on the sample complexity
achievable by polynomial time algorithms.
(2) Based on (1), we develop a blackbox knowledge distillation procedure to
convert an arbitrarily complex classifier to an equally good proper classifier.
(3) By leveraging a simple but overlooked connection to evolvability, we show
any SQ algorithm requires super-polynomially many queries to achieve
.
Moreover we study generalized linear models where for any odd, monotone, and
Lipschitz function . This family includes the previously mentioned
halfspace models as a special case, but is much richer and includes other
fundamental models like logistic regression. We introduce a challenging new
corruption model that generalizes Massart noise, and give a general algorithm
for learning in this setting. Our algorithms are based on a small set of core
recipes for learning to classify in the presence of misspecification.
Finally we study our algorithm for learning halfspaces under Massart noise
empirically and find that it exhibits some appealing fairness properties.Comment: 51 pages, comments welcom
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Evolutionary bilevel optimization for complex control problems and blackbox function optimization
textMost optimization algorithms must undergo time consuming parameter tuning in order to solve complex, real-world control tasks. Parameter tuning is inherently a bilevel optimization problem: The lower level objective function is the performance of the control parameters discovered by an optimization algorithm and the upper level objective function is the performance of the algorithm given its parameterization. In the first part of this thesis, a new bilevel optimization method called MetaEvolutionary Algorithm (MEA) is developed to discover optimal parameters for neuroevolution to solve control problems. In two challenging benchmarks, double pole balancing and helicopter hovering, MEA discovers parameters that result in better performance than hand tuning and other automatic methods. In the second part, MEA tunes an adaptive genetic algorithm (AGA) that uses the state of the population every generation to adjust parameters on the fly. Promising experimental results are shown for standard blackbox benchmark functions. Thus, bilevel optimization in general and MEA in particular are promising approaches for solving difficult optimization tasks.Computer Science
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