Cryptocurrency price prediction using LSTM neural networks

The interest in cryptocurrencies is increasing among individuals and investors. Bitcoin is the leading existing cryptocurrency with the highest market capitalization. However, its high volatility aligns with political uncertainty making it very difficult to predict its value. Therefore, there is a need to create advanced models that use mathematical and statistical methods to reduce investment risk. This research aims to verify if long short-term memory (LSTM), and bidirectional long short-term memory (BiLSTM) neural networks, can be used with Savitzky–Golay filter to predict next-day bitcoin closing prices. We found evidence both networks can be used effectively to predict bitcoin prices. LSTM performed 4.49 mean absolute percentage error (MAPE) and BiLSTM 4.44 MAPE. We also found that using Savitzky– Golay filter and dropout regularization significantly improved the model’s prediction performance.O interesse em moedas digitais tem aumentado por parte de indivíduos e investidores. A bitcoin é a moeda digital com maior capitalização de mercado, no entanto, a sua alta volatilidade alinhada à incerteza política, torna muito difícil prever seu valor. Portanto, existe a necessidade de criar modelos avançados que utilizem métodos matemáticos e estatísticos para reduzir o risco de investimento. Este estudo tem como objetivo verificar se as redes neurais artificiais de memória longo curto prazo (LSTM) e redes bidirecionais de memória longo curto prazo (BiLSTM) podem ser usadas juntamente com o filtro Savitzky-Golay para prever os preços de fecho do dia seguinte da bitcoin. Os resultados mostraram que existe evidência que ambas as redes podem ser usadas de forma efetiva. LSTM obteve um erro percentual absoluto médio (MAPE) de 4.49 e BiLSTM um MAPE de 4,44. Também o uso do filtro Savitzky-Golay e regularização, melhora significativamente o desempenho de previsão dos modelos

Forecasting Bitcoin Prices Using N-BEATS Deep Learning Architecture

The use of computationally intensive systems that employ machine learning algorithms is increasingly common in the field of finance. New state of the art deep learning architectures for time series forecasting are being developed each year making them more accurate than ever. This study evaluates the predictive power of the N-BEATS deep learning architecture trained on Bitcoin daily, hourly, and up-to-the-minute data in comparison with other popular time series forecasting methods such as LSTM and ARIMA. Prediction errors are measured with Mean Average Percentage Error (MAPE), and Root Mean Squared Error (RMSE). The results suggest that the developed N-BEATS model has promising predictive power compared to LSTM and ARIMA models

Four essays on quantitative economics applications to volatility analysis in Emerging Markets and renewable energy projects

[ES]Las decisiones financieras se pueden dividir en decisiones de inversión y decisiones de financiación. En lo que respecta a las decisiones de inversión, la incertidumbre acerca de la dinámica futura de las variables económicas y de las financieras tiene un rol fundamental. Eso, se explica porque los retornos esperados por las empresas y por los inversionistas se pueden ver afectados por los movimientos adversos en los mercados financieros y por los altos niveles de volatilidad. Como consecuencia, resulta crucial realizar un adecuado análisis y modelación de la volatilidad para el proceso de toma de decisiones financieras, por parte de las empresas y el diseño de estrategias de inversión y cobertura por parte de los inversionistas. En este sentido, el estudio de la volatilidad se ha convertido en uno de los temas más interesantes de la investigación en finanzas. Lo anterior ha cobrado mayor relevancia en los últimos años, teniendo en cuenta el escenario de alta volatilidad e incertidumbre que afrontan los mercados a nivel global. Este documento tiene como objetivo abordar cuatro cuestiones centrales, las cuales están relacionadas con la volatilidad financiera como campo de investigación. Esas cuestiones son, la transmisión y spillovers de volatilidad en mercados emergentes, la calibración de la superficie de volatilidad para proyectos de energía renovable y el pronóstico de los rendimientos de activos energéticos y spillovers de volatilidad a través de técnicas de machine learning. En el primer capítulo del documento, se examinan los efectos de transmisión de volatilidad entre un índice de energía y un índice financiero para los Mercados Emergentes. En consecuencia, mediante el uso de un modelo DCC, se muestra que los efectos de transmisión de volatilidad entre los índices empleados para la crisis subprime y la crisis del COVID-19 fueron diferentes. Lo anteriormente dicho, considerando que la primera crisis se originó en el sector financiero y luego se extendió al resto de la economía, mientras que la segunda se originó en el sector real y posteriormente afectó al resto de la economía. Teniendo en cuenta que la relación entre la volatilidad de los mercados es cambiante en el tiempo, en el segundo capítulo se llevó a cabo un análisis dinámico de los spillovers de volatilidad entre materias primas, Bitcoin y un índice de Mercados Emergentes. Así, empleando la metodología propuesta por Diebold y Yilmaz (2012), se concluyó que los efectos de los spillovers de volatilidad entre los activos analizados no son constantes en dirección e intensidad a través del tiempo. En particular, para períodos de crisis como el de la pandemia del COVID-19, hay reversiones en la dirección de los spillovers de volatilidad debido al sector en el que se originó la crisis. Además, en este capítulo se explota la naturaleza dinámica de los spillovers de volatilidad. Por lo tanto, se planteó que el índice de spillovers de volatilidad propuesto por Diebold y Yilmaz puede ser usado como una medida para pronosticar periodos de alta turbulencia. Lo anterior se desarrolló a través de modelos econométricos tradicionales y de técnicas de machine learning. En el tercer capítulo del documento, se propone un modelo que predice los retornos de los precios del carbono y del petróleo. En este sentido, se desarrolló un modelo híbrido, el cual combina las proyecciones obtenidas a partir de diferentes técnicas de machine learning y modelos econométricos tradicionales, obteniéndose resultados los cuales muestran las ventajas de emplear modelos híbridos que incorporan técnicas de machine learning, exclusivamente, para pronosticar variables financieras. Finalmente, en el capítulo cuatro, se presenta una metodología para la estimación de la volatilidad en la valoración de proyectos de energías renovables mediante opciones reales. En esta metodología, la cual es una extensión del enfoque de volatilidad implícita empleada para las opciones financieras, la volatilidad de un proyecto es la volatilidad implícita obtenida a partir de la superficie de la volatilidad de empresas comparables, según una determinada fecha de valoración y dada la relación deuda-capital de un proyecto de energía renovable. En este análisis, se utilizó el modelo estocástico 'alfa-beta-rho' para calibrar la superficie de la volatilidad para la valoración mediante opciones reales. Por último, al final del documento se presentan las conclusiones derivadas de los capítulos mencionados, así como algunas recomendaciones para las futuras investigaciones. [EN]Financial decisions can be divided in investment and financing decisions. Concerning investment decisions, the uncertainty about the future dynamics of financial and economic variables has a central role, considering that the returns expected by firms and investors can be affected by the adverse movements in financial markets and their high volatility. In consequence, the adequate volatility analysis and modeling is crucial for the firm’s financial decision-making process and the design of investing and hedging strategies by investors. In this regard, the study of volatility has become one of the most interesting topics in finance research. The foregoing has become more relevant in recent years considering the scenario of high volatility and uncertainty faced by markets globally. This document aims to address four central issues related to financial volatility as a research area. These are, volatility transmission and spillovers in Emerging Markets, the calibration of the volatility surface for renewable energy projects and the forecast of energy assets returns and volatility spillovers through machine learning techniques. In the first chapter of the document, the volatility transmission effects between an energy index and a financial index for Emerging Markets are examined. Then, by using a DCC model, it is shown that the volatility transmission effects between the employed indices for the subprime crisis and the COVID-19 pandemic were different. This, considering that the former crisis originated in the financial sector and spread to the rest of the economy, while the second originated in the real sector and trasmitted to the rest of the economy posteriorly. Considering that the relationship between markets volatility is time-varying, in the second chapter, a dynamic analysis of volatility spillovers between commodities, Bitcoin and an Emerging Markets index is developed. Employing the methodology proposed by Diebold and Yilmaz (2012), it is concluded that the volatility spillovers effects between the analyzed assets is not constant in direction and intensity over time. In particular, for periods of crisis such as the COVID-19 pandemics, there are reversals in the direction of volatility spillovers due to the sector in which the crises originate. In addition, in this chapter the dynamic nature of volatility spillovers is exploited. Hence, the volatility spillover index proposed by Diebold and Yilmaz is forecasted to be used as a measure to anticipate high turbulence periods. This, through both traditional econometric models and machine learning techniques. In the third chapter, a model for the prediction of carbon and oil prices is proposed. In this sense, a hybrid model that ensembles the forecasts obtained from different machine learning techniques and traditional econometric models is developed, obtaining results that show the advantages of employing hybrid models which combine machine learning techniques, exclusively, to forecast financial variables. In Chapter four, a methodology for the estimation of volatility in renewable energy projects valuation through real options is presented. In this methodology, which is an extension of the implied volatility approach employed for financial options, the volatility of the project is the implied volatility obtained from the volatility surface of comparable firms for a certain valuation date and given debt-to-equity relation of a renewable energy project. In this analysis, the stochastic ‘alpha-beta-rho’ model is utilized to calibrate the volatility surface for real option valuation purposes. Finally, the conclusions derived from the mentioned chapters are presented at the end of the document as well as some recommendations for future research

Applied Data Science Approaches in FinTech: Innovative Models for Bitcoin Price Dynamics

Living in a data-intensive environment is a natural consequence to the continuous innovations and technological advancements, that created countless opportunities for addressing domain-specific challenges following the Data Science approach. The main objective of this thesis is to present applied Data Science approaches in FinTech, focusing on proposing innovative descriptive and predictive models for studying and exploring Bitcoin Price Dynamics and Bitcoin Price Prediction. With reference to the research area of Bitcoin Price Dynamics, two models are proposed. The first model is a Network Vector Autoregressive model that explains the dynamics of Bitcoin prices, based on a correlation network Vector Autoregressive process that models interconnections between Bitcoin prices from different exchange markets and classical assets prices. The empirical findings show that Bitcoin prices from different markets are highly interrelated, as in an efficiently integrated market, with prices from larger and/or more connected exchange markets driving other prices. The results confirm that Bitcoin prices are unrelated with classical market prices, thus, supporting the diversification benefit property of Bitcoin. The proposed model can predict Bitcoin prices with an error rate of about 11% of the average price. The second proposed model is a Hidden Markov Model that explains the observed time dynamics of Bitcoin prices from different exchange markets, by means of the latent time dynamics of a predefined number of hidden states, to model regime switches between different price vectors, going from "bear'' to "stable'' and "bear'' times. Structured with three hidden states and a diagonal variance-covariance matrix, the model proves that the first hidden state is concentrated in the initial time period where Bitcoin was relatively new and its prices were barely increasing, the second hidden state is mostly concentrated in a period where Bitcoin prices were steadily increasing, while the third hidden state is mostly concentrated in the last period where Bitcoin prices witnessed a high rate of volatility. Moreover, the model shows a good predictive performance when implemented on an out of sample dataset, compared to the same model structured with a full variance-covariance matrix. The third and final proposed model, falls within the area of Bitcoin Price Prediction. A Hybrid Hidden Markov Model and Genetic Algorithm Optimized Long Short Term Memory Network is proposed, aiming at predicting Bitcoin prices accurately, by introducing new features that are not usually considered in the literature. Moreover, to compare the performance of the proposed model to other models, a more traditional ARIMA model has been implemented, as well as a conventional Genetic Algorithm-optimized Long Short Term Memory Network. With a mean squared error of 33.888, a root mean squared error of 5.821 and a mean absolute error of 2.510, the proposed model achieves the lowest errors among all the implemented models, which proves its effectiveness in predicting Bitcoin prices

Exploring a Hybrid Algorithm for Price Volatility Prediction of Bitcoin

In recent years, the Bitcoin investment market has become increasingly popular. We collected existing literature on Bitcoin and found that predictions about the role of Bitcoin in investment portfolios and the volatility of Bitcoin price as well as return have become advanced research topics. This study shows our current work on the prediction of Bitcoin price volatility and proposes an idea for predicting the price volatility. We have designed an experiment that compares different combinations of machine learning algorithms with GARCH-type models, intending to compare the effects of these models in the prediction of Bitcoin time series and finally implement an optimized algorithm

Ramalan harga Bitcoin berasaskan polariti sentiment artikel berita dan data pasaran dengan model LSTM

Bitcoin adalah wang digital dan alat pelaburan yang telah mendapat perhatian seluruh dunia sejak kebelakangan ini. Namun, harga Bitcoin yang tidak stabil telah menjadi kebimbangan di kalangan pengguna dan pelabur Bitcoin. Ramalan harga Bitcoin dapat membantu pelabur dan pengguna untuk membina strategi yang efektif dalam pelaburan atau penggunaan. Dengan perkembangan pesat Internet, data dalam talian termasuk artikel berita boleh membantu dalam harga ramalan Bitcoin. Kajian ini bertujuan untuk mengkaji kesan sentimen artikel berita kepada harga Bitcoin dengan tempoh kajian dari September 2017 hingga Ogos 2019. Sehubungan dengan itu, kajian ini memperkenalkan analisis sentimen untuk memahami maklumat artikel berita dalam talian dan menggunakannya sebagai fitur input untuk ramalan harga Bitcoin. Terdapat dua fasa utama dalam kajian ini, iaitu analisis sentimen dan ramalan harga. Dalam analisis sentimen, sentimen diekstrak berdasarkan kaedah leksikon untuk memahami maklumat artikel berita berkaitan dengan pasaran kriptowang. Kriptowang adalah sejenis sistem pembayaran digital dan monetari yang mana transaksi dilakukan dengan cara desentralisasi yang merupakan transaksi kewangan rakan-ke-rakan tanpa melalui institusi kewangan. Dengan kata lain, Bitcoin tidak bergantung kepada perantara pihak ketiga untuk memproses pembayaran, ia menggunakan bukti kriptografi dalam komputer untuk memproses dan mengesahkan kesahihan dan menyebarkan antara rangkaian (Nakamoto 2008). Dalam ramalan harga, sentimen digunakan sebagai fitur input dan model Memori Jangka Panjang Pendek (LSTM) digunakan dalam fasa ramalan harga. Dengan data pasaran dan artikel berita sebagai sampel, keputusan menunjukkan sentimen artikel berita dapat mengurangkan kesilapan dalam ramalan harga Bitcoin

Predicting Time Series Using an Automatic New Algorithm of the Kalman Filter

Time series forecasting is one of the main venues followed by researchers in all areas. For this reason, we develop a new Kalman filter approach, which we call the alternative Kalman filter. The search conditions associated with the standard deviation of the time series determined by the alternative Kalman filter were suggested as a generalization that is supposed to improve the classical Kalman filter. We studied three different time series and found that in all three cases, the alternative Kalman filter is more accurate than the classical Kalman filter. The algorithm could be generalized to time series of a different length and nature. Therefore, the developed approach can be used to predict any time series of data with large variance in the model error that causes convergence problems in the prediction

Bitcoin Network Mechanics: Forecasting the BTC Closing Price Using Vector Auto-Regression Models Based on Endogenous and Exogenous Feature Variables

The Bitcoin (BTC) market presents itself as a new unique medium currency, and it is often hailed as the “currency of the future”. Simulating the BTC market in the price discovery process presents a unique set of market mechanics. The supply of BTC is determined by the number of miners and available BTC and by scripting algorithms for blockchain hashing, while both speculators and investors determine demand. One major question then is to understand how BTC is valued and how different factors influence it. In this paper, the BTC market mechanics are broken down using vector autoregression (VAR) and Bayesian vector autoregression (BVAR) prediction models. The models proved to be very useful in simulating past BTC prices using a feature set of exogenous variables. The VAR model allows the analysis of individual factors of influence. This analysis contributes to an in-depth understanding of what drives BTC, and it can be useful to numerous stakeholders. This paper’s primary motivation is to capitalize on market movement and identify the significant price drivers, including stakeholders impacted, effects of time, as well as supply, demand, and other characteristics. The two VAR and BVAR models are compared with some state-of-the-art forecasting models over two time periods. Experimental results show that the vector-autoregression-based models achieved better performance compared to the traditional autoregression models and the Bayesian regression models

Time series forecasting by combining LSTM RNN with ARIMA method

Dissertation presented as the partial requirement for obtaining a Master's degree in Information Management, specialization in Knowledge Management and Business IntelligenceThis study aims to analyze the performance of the ensemble model – the combination of Long ShortTerm Memory Recurring Neural Network model with the ARIMA model. We developed these models separately to perform the best on their own in predicting prices 1, 7, and 14 observations ahead while taking into account the last 30, 60 and 90 observations and checking if the combination of them outperforms the standalone models. We evaluated the models based on RMSE and their ability to predict the turning points. Models were developed and tested on two different types of securities – index S&P 500 and cryptocurrency Bitcoin (BTC). The combined methods demonstrated strong performance on BTC data set and gave at least 90% turning point prediction accuracy when predicting the price for one observation ahead. For the S&P 500 data set, the performance of the stacked model was poor – it outperformed the standalone models only in one test out of eighteen – while predicting prices one observation ahead, looking back at the past 30 observations