Artificial intelligence in steam cracking modeling : a deep learning algorithm for detailed effluent prediction

Chemical processes can benefit tremendously from fast and accurate effluent composition prediction for plant design, control, and optimization. The Industry 4.0 revolution claims that by introducing machine learning into these fields, substantial economic and environmental gains can be achieved. The bottleneck for high-frequency optimization and process control is often the time necessary to perform the required detailed analyses of, for example, feed and product. To resolve these issues, a framework of four deep learning artificial neural networks (DL ANNs) has been developed for the largest chemicals production process-steam cracking. The proposed methodology allows both a detailed characterization of a naphtha feedstock and a detailed composition of the steam cracker effluent to be determined, based on a limited number of commercial naphtha indices and rapidly accessible process characteristics. The detailed characterization of a naphtha is predicted from three points on the boiling curve and paraffins, iso-paraffins, olefins, naphthenes, and aronatics (PIONA) characterization. If unavailable, the boiling points are also estimated. Even with estimated boiling points, the developed DL ANN outperforms several established methods such as maximization of Shannon entropy and traditional ANNs. For feedstock reconstruction, a mean absolute error (MAE) of 0.3 wt% is achieved on the test set, while the MAE of the effluent prediction is 0.1 wt%. When combining all networks-using the output of the previous as input to the next-the effluent MAE increases to 0.19 wt%. In addition to the high accuracy of the networks, a major benefit is the negligible computational cost required to obtain the predictions. On a standard Intel i7 processor, predictions are made in the order of milliseconds. Commercial software such as COILSIM1D performs slightly better in terms of accuracy, but the required central processing unit time per reaction is in the order of seconds. This tremendous speed-up and minimal accuracy loss make the presented framework highly suitable for the continuous monitoring of difficult-to-access process parameters and for the envisioned, high-frequency real-time optimization (RTO) strategy or process control. Nevertheless, the lack of a fundamental basis implies that fundamental understanding is almost completely lost, which is not always well-accepted by the engineering community. In addition, the performance of the developed networks drops significantly for naphthas that are highly dissimilar to those in the training set. (C) 2019 THE AUTHORS. Published by Elsevier LTD on behalf of Chinese Academy of Engineering and Higher Education Press Limited Company

Opportunities of artificial neural network generated VGA: Training a Multilayer Perceptron to recognize the underlying structures of space

This paper presents the research conducted with the aim of understanding if new advances in computer science, more specifically a type of supervised, feedforward Artificial Neural Network, a Multilayer Perceptron (MLP) is able to estimate the values of Visibility Graph Analysis (VGA) without the need for expensive calculation. The overarching hypothesis is that an MLP can be setup in a way that it can be trained to learn the relationship between spatial configuration and the VGA (neighbourhood size and clustering coefficient) derived from it. Two hypotheses are stated: firstly, if such an MLP can be created than it will be able to generate spatial configurations for specific VGA values as inputs (mode A); secondly, the network would be able to generate VGA when presented with spatial configuration faster, compared to current method and with negligible error (mode B). The hypotheses were tested by creating unique setups of an MLP for each mode, all of which had a different configuration. As each combination of possible setups were tested, the performance of the networks could be compared to each other and to the traditional method of VGA calculation. Both mode A and mode B was able to achieve satisfying results that prove that an MLP is able to generate –with limitations- configurations based on VGA input and it is able to calculate the neighbourhood size and the clustering coefficient of a 2D layout substantially faster and with negligible error. All MLPs were created at a generic space, therefore the MLP taught once can be adopted universally to most spaces. The implications of the two systems is that spatial analysis can be integrated into the design process, enabling interactive, instant analysis and the possible deployment of optimisation procedures, for instance a Genetic Algorithm

Information asset analysis: credit scoring and credit suggestion

Risk assessment is important for financial institutions, especially in loan applications. Some have already implemented their own credit-scoring mechanisms to evaluate their clients' risk and make decisions based on this indicator. In fact, the data gathered by financial institutions is a valuable source of information to create information assets, from which credit-scoring mechanisms can be developed. The purpose of this paper is to create, from information assets, a decision mechanism that is able to evaluate a client's risk. Furthermore, a suggestive algorithm is presented to better explain and give insights on how the decision mechanism values attributes

Towards The Deep Semantic Learning Machine Neuroevolution Algorithm: An exploration on the CIFAR-10 problem task

Dissertation presented as the partial requirement for obtaining a Master's degree in Data Science and Advanced AnalyticsSelecting the topology and parameters of Convolutional Neural Network (CNN) for a given supervised machine learning task is a non-trivial problem. The Deep Semantic Learning Machine (Deep-SLM) deals with this problem by automatically constructing CNNs without the use of the Backpropagation algorithm. The Deep-SLM is a novel neuroevolution technique and functions as stochastic semantic hill-climbing algorithm searching over the space of CNN topologies and parameters. The geometric semantic properties of the Deep-SLM induce a unimodel error space and eliminate the existence of local optimal solutions. This makes the Deep-SLM potentially favorable in terms of search efficiency and effectiveness. This thesis provides an exploration of a variant of the Deep-SLM algorithm on the CIFAR-10 problem task, and a validation of its proof of concept. This specific variant only forms mutation node ! mutation node connections in the non-convolutional part of the constructed CNNs. Furthermore, a comparative study between the Deep-SLM and the Semantic Learning Machine (SLM) algorithms was conducted. It was observed that sparse connections can be an effective way to prevent overfitting. Additionally, it was shown that a single 2D convolution layer initialized with random weights does not result in well-generalizing features for the Deep-SLM directly, but, in combination with a 2D max-pooling down sampling layer, effective improvements in performance and generalization of the Deep-SLM could be achieved. These results constitute to the hypothesis that convolution and pooling layers can improve performance and generalization of the Deep-SLM, unless the components are properly optimized.Selecionar a topologia e os parâmetros da Rede Neural Convolucional (CNN) para uma tarefa de aprendizado automático supervisionada não é um problema trivial. A Deep Semantic Learning Machine (Deep-SLM) lida com este problema construindo automaticamente CNNs sem recorrer ao uso do algoritmo de Retro-propagação. A Deep-SLM é uma nova técnica de neuroevolução que funciona enquanto um algoritmo de escalada estocástico semântico na pesquisa de topologias e de parâmetros CNN. As propriedades geométrico-semânticas da Deep-SLM induzem um unimodel error space que elimina a existência de soluções ótimas locais, favorecendo, potencialmente, a Deep-SLM em termos de eficiência e eficácia. Esta tese providencia uma exploração de uma variante do algoritmo da Deep-SLM no problemo de CIFAR-10, assim como uma validação do seu conceito de prova. Esta variante específica apenas forma conexões nó de mutação!nó de mutação na parte non convolucional da CNN construída. Mais ainda, foi conduzido um estudo comparativo entre a Deep-SLM e o algoritmo da Semantic Learning Machine (SLM). Tendo sido observado que as conexões esparsas poderão tratar-se de uma forma eficiente de prevenir o overfitting. Adicionalmente, mostrou-se que uma singular camada de convolução 2D, iniciada com valores aleatórios, não resulta, directamente, em características generalizadas para a Deep-SLM, mas, em combinação com uma camada de 2D max-pooling, melhorias efectivas na performance e na generalização da Deep-SLM poderão ser concretizadas. Estes resultados constituem, assim, a hipótese de que as camadas de convolução e pooling poderão melhorar a performance e a generalização da Deep-SLM, a não ser que os componentes sejam adequadamente otimizados

LFSR Next Bit Prediction through Deep Learning

Pseudorandom bit sequences are generated using deterministic algorithms to simulate truly random sequences. Many cryptographic algorithms use pseudorandom sequences, and the randomness of these sequences greatly impacts the robustness of these algo-rithms. Important crypto primitive Linear Feedback Shift Register (LFSR) and its combina-tions have long been used in stream ciphers for the generation of pseudorandom bit sequences. The sequences generated by LFSR can be predicted using the traditional Ber-lekamp Massey Algorithm, which solves LFSR in 2×n number of bits, where n is the de-gree of LFSR. Many different techniques based on ML classifiers have been successful at predicting the next bit of the sequences generated by LFSR. However, the main limitation in the existing approaches is that they require a large number (as compared to the de-gree of LFSR) of bits to solve the LFSR. In this paper, we have proposed a novel Pattern Duplication technique that exponentially reduces the input bits requirement for training the ML Model. This Pattern Duplication technique generates new samples from the available data using two properties of the XOR function used in LFSRs. We have used the Deep Neural Networks (DNN) as the next bit predictor of the sequences generated by LFSR along with the Pattern Duplication technique. Due to the Pattern Duplication tech-nique, we need a very small number of input patterns for DNN. Moreover, in some cases, the DNN model managed to predict LFSRs in less than 2n bits as compared to the Ber-lekamp Massey Algorithm. However, this technique was not successful in cases where LFSRs have primitive polynomials with a higher number of tap points

Combined optimization algorithms applied to pattern classification

Accurate classification by minimizing the error on test samples is the main goal in pattern classification. Combinatorial optimization is a well-known method for solving minimization problems, however, only a few examples of classifiers axe described in the literature where combinatorial optimization is used in pattern classification. Recently, there has been a growing interest in combining classifiers and improving the consensus of results for a greater accuracy. In the light of the "No Ree Lunch Theorems", we analyse the combination of simulated annealing, a powerful combinatorial optimization method that produces high quality results, with the classical perceptron algorithm. This combination is called LSA machine. Our analysis aims at finding paradigms for problem-dependent parameter settings that ensure high classifica, tion results. Our computational experiments on a large number of benchmark problems lead to results that either outperform or axe at least competitive to results published in the literature. Apart from paxameter settings, our analysis focuses on a difficult problem in computation theory, namely the network complexity problem. The depth vs size problem of neural networks is one of the hardest problems in theoretical computing, with very little progress over the past decades. In order to investigate this problem, we introduce a new recursive learning method for training hidden layers in constant depth circuits. Our findings make contributions to a) the field of Machine Learning, as the proposed method is applicable in training feedforward neural networks, and to b) the field of circuit complexity by proposing an upper bound for the number of hidden units sufficient to achieve a high classification rate. One of the major findings of our research is that the size of the network can be bounded by the input size of the problem and an approximate upper bound of 8 + √2n/n threshold gates as being sufficient for a small error rate, where n := log/SL and SL is the training set