Using neural networks and support vector machines for default prediction in South Africa

A thesis submitted to the Faculty of Computer Science and Applied Mathematics, University of Witwatersrand, in fulfillment of the requirements for the Master of Science (MSc) Johannesburg Feb 2017This is a thesis on credit risk and in particular bankruptcy prediction. It investigates the application of machine learning techniques such as support vector machines and neural networks for this purpose. This is not a thesis on support vector machines and neural networks, it simply looks at using these functions as tools to preform the analysis. Neural networks are a type of machine learning algorithm. They are nonlinear mod- els inspired from biological network of neurons found in the human central nervous system. They involve a cascade of simple nonlinear computations that when aggre- gated can implement robust and complex nonlinear functions. Neural networks can approximate most nonlinear functions, making them a quite powerful class of models. Support vector machines (SVM) are the most recent development from the machine learning community. In machine learning, support vector machines (SVMs) are su- pervised learning algorithms that analyze data and recognize patterns, used for clas- si cation and regression analysis. SVM takes a set of input data and predicts, for each given input, which of two possible classes comprises the input, making the SVM a non-probabilistic binary linear classi er. A support vector machine constructs a hyperplane or set of hyperplanes in a high or in nite dimensional space, which can be used for classi cation into the two di erent data classes. Traditional bankruptcy prediction medelling has been criticised as it makes certain underlying assumptions on the underlying data. For instance, a frequent requirement for multivarate analysis is a joint normal distribution and independence of variables. Support vector machines (and neural networks) are a useful tool for default analysis because they make far fewer assumptions on the underlying data. In this framework support vector machines are used as a classi er to discriminate defaulting and non defaulting companies in a South African context. The input data required is a set of nancial ratios constructed from the company's historic nancial statements. The data is then Divided into the two groups: a company that has defaulted and a company that is healthy (non default). The nal data sample used for this thesis consists of 23 nancial ratios from 67 companies listed on the jse. Furthermore for each company the company's probability of default is predicted. The results are benchmarked against more classical methods that are commonly used for bankruptcy prediction such as linear discriminate analysis and logistic regression. Then the results of the support vector machines, neural networks, linear discriminate analysis and logistic regression are assessed via their receiver operator curves and pro tability ratios to gure out which model is more successful at predicting default.MT 201

The Greek Current Account Deficit:Is it Sustainable after all?

The large Greek current account deficit figures reported during the past few years have become the source of increasing concern regarding its sustainability. Bearing in mind the variety of techniques employed and the views expressed as regards the analysis and the assessment of the size of the current account deficit, this paper resorts to using neural network architectures to demonstrate that, despite its size, the current account deficit of Greece can be considered sustainable. This conclusion, however, is not meant to neglect the structural weaknesses that lead to such a deficit. In fact, even in the absence of any financing requirements these high deficit figures point to serious competitiveness losses with everything that these may entail for the future performance of the Greek economy.Neural Networks; Current Account Deficit Sustainability

Forecasting power of neural networks in cryptocurrency domain : Forecasting the prices of Bitcoin, Ethereum and Cardano with Gated Recurrent Unit and Long Short-Term Memory

Machine learning has developed substantially during the past decades and more emphasis has gone to deeper machine learning methods, i.e., artificial neural networks, computer-based networks seeking to mimic how the human brain functions. The groundwork for ANN research was established already in the 1940s and the advancement of ANNs has been ex-tensive. Price prediction of different financial assets is a broadly studied field, as researchers have been trying to create models to predict the volatile and noisy environment of financial markets. Also, ANNs have been placed for these hard prediction tasks, as their advantage is the ability to find non-linear patterns in uncertain and volatile setting. Cryptocurrencies have made their way to the common audience in the past years. After Nakamoto (2008) presented the first proposal for an electronic cash system, Bitcoin, the number of different cryptocurrencies has exceeded over 8 000. Also, the market capitaliza-tion of all cryptocurrencies has grown rapidly, in November 2021 the aggregate market capi-talization topped 3 000 billion U.S. dollars. Cryptocurrencies are not a small concept for closed groups of tech-people, but a phenomenon that concerns also in the governmental level. This study utilizes recurrent neural networks, GRU and LSTM, in the prediction task regarding cryptocurrencies. In addition to trading data, this study uses Google trend-based popularity score to try to better the ANNs accuracy. In addition to the sole prediction task, the study compares the two used RNN architectures and presents the performance and accuracy with selected performance measures. The results show that recurrent neural networks have potential in prediction tasks in the cryptocurrency domain. The constructed models were able to find coherent trends in the price fluctuations but the average differences on actual and predicted prices were compara-tively high, with the introduced simple RNN models. On average, the LSTM model was able to predict the cryptocurrency prices more accurately, but the GRU model showed also great evidence of prediction accuracy in the domain. All in all, the cryptocurrency prediction task is a hard task due to its volatile nature, but his study shows great evidence for ANNs ability to predict cryptocurrency prices. Considering the findings, further research could be applied to more optimized and complex ANN models as the models used in the study were relatively simple one-layer models.Koneoppiminen on kehittynyt erittäin paljon viimeisten vuosikymmenten aikana, painottuen enemmän syvempien koneoppimisen metodien, kuten keinotekoisten neuroverkkojen (ANN), kehitykseen. Keinotekoiset neuroverkot ovat tietokoneeseen perustuvia verkkoja, jotka pyrkivät jäljittelemään ihmisaivojen toimintaa. Keinotekoisten neuroverkkojen tutki-mus on alkanut jo 1940-luvulla, josta lähtien kyseisten verkkojen kehitys on ollut nopeaa. Eri omaisuuslajien hintakehityksen ennustaminen on laajasti tutkittu alue, kun tutkijat ovat yrit-täneet luoda malleja, joilla he ovat pyrkineet ennustamaan epävarmaa rahoitusmarkkinaym-päristöä. Keinotekoiset neuroverot on valjastettu tähän vaikeaan tehtävän, koska niiden selkeänä etuna on kyky löytää epälineaarisia yhteyksiä epävarmassa ja epävakaassa ympäris-tössä. Viime vuosien aikana kryptovaluutat ovat yleistyneet huomattavasti, niin yksityissijoittajien kun institutionaalisten sijoittajien joukossa. Sen jälkeen, kun Nakamoto (2008) esitteli en-simmäisen ehdotuksen käteisen ja valuutan sähköisestä järjestelmästä, kryptovaluuttojen lukumäärä on kasvanut yli 8 000 yksittäiseen valuuttaan. Samaan aikaan kryptovaluuttojen yhteenlaskettu markkina-arvo on kasvanut räjähdysmäisesti, marraskuussa 2021 kokonais-markkina-arvo kasvoi yli 3 000 miljardiin Yhdysvaltojen dollariin. Nykyään kryptovaluutat eivät ole vain konsepti suljetuille teknologiasta kiinnostuneille ryhmille, vaan ilmiö, joka vaikuttaa myös valtiollisella tasolla. Tämä tutkimus hyödyntää toistuvia neuroverkkoja (recurrent neural networks), GRU ja LSTM, kryptovaluuttojen hintakehityksen ennustamisessa. Kaupankäyntitietojen lisäksi, tut-kimuksessa käytetään Googlen hakutiedusteluihn perustuvaa Google Trend suosiomittaria, neuroverkkojen tarkkuuden parantamiseksi. Kryptovaluuttojen hintakehityksen ennustami-sen lisäksi, tutkimuksessa verrataan kahta RNN-rakennetta ja esitellään molempien verkko-jen tarkkuutta sekä verrataan sitä valituilla tarkkuusmittareilla. Tutkimuksen tulokset osoittavat, että yksinkertaisilla RNN-rakenteilla on selkeää potentiaalia kryptovaluuttojen hintakehityksen ennustamisessa. Tutkimuksessa luodut mallit löytävät johdonmukaisia ja selkeitä trendejä, mutta keskimääräiset erotukset todellisilla ja ennuste-tuilla hinnoilla oli suhteellisesti korkeat. Tutkituista malleista LSTM-malli tuottaa keskimäärin tarkempia ennusteita kuin GRU-malli, mutta erot mallien tarkkuuksissa ovat pienet. Kokonai-suudessaan kryptovaluuttojen hintojen ennustaminen on vaikea tehtävä kryptovaluut-tamarkkinan epävakaan luonteen johdosta, tämä tutkimus kuitenkin osoittaa näyttöä keino-tekoisten neuroverkkojen kyvystä ennustaa kryptovaluuttojen hintoja. Ottaen huomioon tutkimuksen löydökset, lisätutkimusta voisi soveltaa tarkemmin optimoituihin ja kompleksi-simpiin keinotekoisiin neuroverkkoihin, sillä tässä tutkimuksessa käytetyt mallit olivat suh-teellisen yksinkertaisia

Time series prediction and forecasting using Deep learning Architectures

Nature brings time series data everyday and everywhere, for example, weather data, physiological signals and biomedical signals, financial and business recordings. Predicting the future observations of a collected sequence of historical observations is called time series forecasting. Forecasts are essential, considering the fact that they guide decisions in many areas of scientific, industrial and economic activity such as in meteorology, telecommunication, finance, sales and stock exchange rates. A massive amount of research has already been carried out by researchers over many years for the development of models to improve the time series forecasting accuracy. The major aim of time series modelling is to scrupulously examine the past observation of time series and to develop an appropriate model which elucidate the inherent behaviour and pattern existing in time series. The behaviour and pattern related to various time series may possess different conventions and infact requires specific countermeasures for modelling. Consequently, retaining the neural networks to predict a set of time series of mysterious domain remains particularly challenging. Time series forecasting remains an arduous problem despite the fact that there is substantial improvement in machine learning approaches. This usually happens due to some factors like, different time series may have different flattering behaviour. In real world time series data, the discriminative patterns residing in the time series are often distorted by random noise and affected by high-frequency perturbations. The major aim of this thesis is to contribute to the study and expansion of time series prediction and multistep ahead forecasting method based on deep learning algorithms. Time series forecasting using deep learning models is still in infancy as compared to other research areas for time series forecasting.Variety of time series data has been considered in this research. We explored several deep learning architectures on the sequential data, such as Deep Belief Networks (DBNs), Stacked AutoEncoders (SAEs), Recurrent Neural Networks (RNNs) and Convolutional Neural Networks (CNNs). Moreover, we also proposed two different new methods based on muli-step ahead forecasting for time series data. The comparison with state of the art methods is also exhibited. The research work conducted in this thesis makes theoretical, methodological and empirical contributions to time series prediction and multi-step ahead forecasting by using Deep Learning Architectures

Bitcoin Price Prediction Using Machine Learning Techniques

This paper discusses, trying to accurately assess the price of Bitcoin by looking at differ-ent parameters affects the value of Bitcoin. In our work, we focus on understanding and seeing the evolution of Bitcoin daily market, a1 and gaining intuition in the most rele-vant aspects surrounding the Bitcoin price. In the meantime, market capitalization of publicly traded cryptocurrencies exceeds $ 230 billion. The most important cryptocur-rency, Bitcoin, is used primarily as a digital value store, and its pricing opportunities have been extensively considered. These features are described in more detail in the fol-lowing paragraph: details of the main Bitcoin, as described in the paper. Bitcoin is the most expensive digital currency in the market. However, Bitcoin prices have been highly volatile, making it difficult to forecast. As a result, the goal of this research is to find the most efficient and accurate model for predicting Bitcoin prices using various machine learning algorithms. Several regression models with scikit-learn and Keras libraries were tested using 1-minute interval trading data from the Bitcoin exchange website bit stamp from January 1. 2012 to January 8, 2018. The best results showed a Mean Squared Error (MSE) as low as 0.00002 and an R- Square (R2) as high as 99.2 percent

An Artificial Neural Network Approach for Credit Risk Management

The objective of the research is to analyze the ability of the artificial neural network model developed to forecast the credit risk of a panel of Italian manufacturing companies. In a theoretical point of view, this paper introduces a literature review on the application of artificial intelligence systems for credit risk management. In an empirical point of view, this research compares the architecture of the artificial neural network model developed in this research to another one, built for a research conducted in 2004 with a similar panel of companies, showing the differences between the two neural network models

Artificial Intelligence in Smart Tourism: A Conceptual Framework

Smart tourism destination as: an innovative tourist destination, built on an infrastructure of state-of-the-art technology guaranteeing the sustainable development of tourist areas, accessible to everyone, which facilitates the visitor’s interaction with and integration into his or her surroundings, increases the quality of the experience at the destination, and improves residents’ quality of life. Lopez de Avila (2015). Smart tourism involves multiple components and layers of “smart” include (1) Smart Destinations which was special cases of smart cities integration of ICT’s into physical infrastructure, (2) Smart experience which specifically focus on technology-mediated tourism experience and their engagement through personalization, context-awareness and real-time monitoring, (3) Smart business refer to the complex business ecosystem that creates and supports the exchange of touristic resource and the co-creation of tourism experience. Gretzel et al, (2015). Smart tourism also clearly relies on the ability to not only collect enormous of data but to intelligently store, process, combine, analyze and use big data to inform business innovation, operations and services by artificial intelligence and big data technique. The rapid development of information communication technology (ICT) such as artificial intelligent, cloud computing, mobile device, big data mining and social media cause computing, storage and communication relevant software and hardware popular. Facebook, Amazon, Apple, Microsoft and Google have risen rapidly since 2000. In recent years, Emerging technologies such as Artificial Intelligence, Internet of Thing, Robotic, Cyber Security, 3D printer and Block chain also accelerate the development of industry toward digital transformation trend such as Fintech, e-commerce, smart cities, smart tourism, smart healthcare, smart manufacturing... This study proposes a conceptual framework that integrates (1) artificial intelligence/machine learning, (2) institution/organizational and (3) business processes to assist smart tourism stake holder to leverage artificial intelligence to integrate cross-departmental business and streamline key performance metrics to build a business-level IT Strategy. Artificial intelligence as long as the function includes (1) Cognitive engagement to (voice/pattern recognition function) (2) Cognitive process automation (Robotic Process Automation) (3) Cognitive insight (forecast, recommendation)