Publications by Selcuk Disci
Military Expenditure Estimation with RJAGS Simulation
The side effect of the ongoing Russian occupation was that it stimulated countries’ intentions to increase their military budgets. Last month following the invasion, Germany announced a budget of 100 billion € for the restructuring of the army and announced that it would spend %2 of its GDP every year. Of course, it is not a good development ...
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Modeling with Interaction Terms, and Waffle Chart for Comparing: Immigration Flow to the West
There has been a massive debate about the refugee crisis in Turkey for a long time. Turkish people blame immigrants (mostly from Syria) for the worsening economy, and they believe that the immigrants are in wealthy conditions while they themselves suffer from bad economic conditions. I want to check the accuracy of these claims. First, we will co...
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Food Crisis Analysis and, Forecasting with Neural Network Autoregression
The war between Russia and Ukraine has affected the global food supply other than many vital things. Primarily cereal crop products have been affected the most because the imports have been provided to the world mainly through Ukraine and Russia. Let’s check the situation we’ve mentioned for G20 countries. library(tidyverse) library(fpp3) lib...
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Comparing Plastic Pollution: Modeling with Tidymodels and Variable Importance
Plastic wastes are one of the most dominant pollution factors in the environment as we live in an era where modern industries exist. The most dangerous part of this kind of pollution is mismanaged plastic waste, which ends up mixing into the ocean in the end. Our World in Data, which we’ll be taking the data for this article, claims that lower-...
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Trend Forecasting Models and Seasonality with Time Series
Gasoline prices always is an issue in Turkey; because Turkish people love to drive where they would go but they complain about the prices anyway. I wanted to start digging for the last seven years’ prices and how they went. I have used unleaded gasoline 95 octane prices from Petrol Ofisi which is a fuel distribution company in Turke...
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Trend Forecasting Models and Seasonality with Time Series
Gasoline prices always is an issue in Turkey; because Turkish people love to drive where they would go but they complain about the prices anyway. I wanted to start digging for the last seven years’ prices and how they went. I have used unleaded gasoline 95 octane prices from Petrol Ofisi which is a fuel distribution company in Turkey. I arrange...
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Testing the Correlation between Time Series Variables
In the previous article, we examined trends and seasonality in gasoline prices in Turkey. This time we will examine whether the gasoline prices are related to the variables that are thought to affect gasoline prices the most by the Turkish people. One of the variables is the Brent crude oil prices that are averaged monthly in dollars; the other i...
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Turkey vs. Germany: COVID-19
In Turkey, some parts of society always compare Turkey to Germany and think that we are better than Germany for a lot of issues. The same applies to COVID-19 crisis management; is that reflects to true? We will use two variables for compared parameters; the number of daily new cases and daily new deaths.First, we will compare the mean of new cas...
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Model Selection: Adjusted Coefficient of Determination-Variance Tradeoff
In my previous article, we analyzed the COVID-19 data of Turkey and selected the cubic model for predicting the spread of disease. In this article, we will show in detail why we selected the cubic model for prediction and see whether our decision was right or not. When we analyze the regression trend models we should consider overfitting and unde...
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Time Series Forecasting: KNN vs. ARIMA
It is always hard to find a proper model to forecast time series data. One of the reasons is that models that use time-series data often expose to serial correlation. In this article, we will compare k nearest neighbor (KNN) regression which is a supervised machine learning method, with a more classical and stochastic process, autoregressive inte...
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