978-1-5386-5541-2/18/$31.00 ©2018 IEEE
Ito calculus-machine learning projection of forward
US dollar-Ghana cedi rates
Paul A. Agbodza
Department of Mathematical Sciences
University of Mines and Technology
Tarkwa, Ghana
https://orcid.org/0000-0003-0069-5298
NB. This is a preprint published in
2019 International Conference on
Computing, Computational Modelling
and Applications.
IEEE Explore 20 June 2019.
DOI: 10.1109/ICCMA.2019.00023
Abstract—In this paper the fundamental solution to
CMSVJD is implemented to simulate USD/GHS forward
exchange rates under the condition of jumps. CMSVJD
was generalized in this study to include conditions of ‘no
jump’ and ‘reduced parameters’. The model captures
both stochastic volatility and jumps. Stochastic calculus
modeling and machine learning interface is the answer to
speculators and chartists driving prices in the Ghana
interbank market (a frontier market). Codes written in R
were used for simulation and plot of results. A 5-fold cross
validation was used to create the test sample data, as
proxy for forward rates required to validate the
performance of the model. The resultant machine yields a
predictive result of forward USD/GHS rates with a mean
squared error of 0.169% and 0.5%.
Keywords—USD/GHS, volatility, foreign exchange, jumps,
frontier markets, cross validation
I. INTRODUCTION
A new equation to study the dynamics of the USD/GHS
foreign exchange returns is the Correlated Multifactor
Stochastic Variance Jump Diffusion (CMSVJD) model [1].
Since the early approach of [2] to apply learning networks to
model derivative securities, the application of machine
learning tools to financial engineering is an area of current
research. Projecting foreign exchange rates is the most
difficult endeavor. In a frontier market, where there is no
derivative securities trading, forward rates are non-existent.
Annual reports [3] and [4] show that speculative activity is
brisk and drives prices in the Ghana interbank market.
CMSVJD was implemented to resolve these difficulties. This
is a two-state simultaneous equation of the evolution of rates
and variance. The fundamental solution to this equation gives
the discounting factor for determining forward rates of the
USD/GHS exchange rate. In the next four sections, the model
and the results from implementing the model were presented.
Finally, the results were discussed and the implications of the
study given in the conclusion.
II. METHOD
The method used is stochastic calculus modelled as
Brownian motion and Poisson jumps. The multifactor jump-
diffusion equation, CMSVJD of [1] is the main tool for
implementation in this paper. Cross-validation of machine
learning was also applied [5]. Five-fold cross validation was
used. Computer-intensive methods (monte carlo or random
simulation) were employed to train and test the machine.
Bootstrap samples were created as initial FX values to be fed
in the machine for projection. The data used for
implementation of the model was obtained from [6] and [7].
The data spans July 2, 2007 to February 18, 2019 totaling
3,075 trading days or data points.
Common abbreviations used are FX for foreign exchange;
and USD/GHS for US Dollar-Ghana Cedi exchange rate.
Mean squared error is abbreviated as mse.
III. FORWARD RATE PROJECTION MODEL
In this paper, the model is implemented on the data split with
a 5-fold cross validation to determine the forward exchange
rates. There are jumps in the data which is modelled as a
compound Poisson process and the volatility is itself
modelled as a stochastic process. Implementing the model
requires a 5-fold cross validation to generate training and test
samples in the data. This method was adopted to solve the
problem of lack of forward rates in a frontier financial market
without derivative trading.
A. Econometric Characteristics of Data
The distribution of the returns data is shown in the log rate of
returns graph (Fig. 1) which exhibits features of random walk.
They exhibit random volatility.
Fig 1: US Dollar-Ghana Cedi Log Returns (02/07/2007 – 18/02/2019)
From Fig. 1, the jumps are conspicuously seen. These are
up and down movements as a result of unexpected events or
crashes during trading days. These jumps can be considered
outliers.
The kernel density (Fig. 2) shows that the data is unimodal.
Different kernels were chosen but the kernel choice did not
alter the nature of the modality. This suggests that the
USD/GHS data has homogenous features.