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PhD Candidate • ML for Time Series • Stock Market Forecasting • R Developer • Public Writing

Posts

How to draw the Economist-style graph with ggplot2 in R?

28 minute read

Published:

I think everyone agrees on the fact that the Economist magazine produces very-well designed graphics, sometimes the best in the world. The success behind their graph lies on the ability of explaining complex matters in a simpler way by employing traditional data visualization techniques such as line graph or bar plot. They put emphasis on the message they want to convey rather than the aesthetics of the graph itself. They also have a clear hiearchy in their plots and use colors, fonts and lines which represents the brand identity of the magazine.

The 10 Golden Rules of Time Series Forecasting

3 minute read

Published:

Forecasting is more than just fitting a model. Here are 10 essential rules to ensure your time series models are robust, reliable, and realistic.

Tutorial for Developing an Advanced Stock Dashboard for the S&P 500 for the 2025 Posit Table Contest

7 minute read

Published:

This tutorial breaks down the development of an R Shiny application titled S&P 500 Monitoring Dashboard for the 2025 Posit Table Dashboard. This app effectively combines interactive financial data visualization (plotly), beautiful data tables (gt, gtExtras), web scraping (rvest), and external API integration (riingo, ellmer/Gemini AI) within a custom, sleek dark theme. You can access the app through this link

Bddkr

9 minute read

Published:

bddkR Tutorial: Working with Turkish Banking Data

How to draw a candlestick chart in R? - Both ggplot2 and plotly

6 minute read

Published:

Candlestick charts are a type of financial chart used to depict the price movements of an asset over a specific period. Each “candlestick” represents a time frame—such as a day, hour, or minute—and displays four key pieces of data: the opening price, closing price, highest price, and lowest price within that period. The body of the candlestick shows the range between the opening and closing prices, while the wicks (also known as shadows) extend to the highest and lowest prices. If the closing price is higher than the opening price, the candlestick is typically colored green or left hollow to indicate a price increase. Conversely, if the closing price is lower than the opening price, it is colored red or filled to signify a price decrease.

R’da ggplot2 paketi kullanarak Türkiye Haritası Çizdirmek

15 minute read

Published:

2018 yılında hazırlamış olduğum R’da ggplot2 ve maps Kutuphanelerini Kullanarak Harita Cizdirmek adlı yazımda, R’da ggplot2 ve maps paketlerini kullanarak harita çizdirmeyi anlatmıştım. Yıllar içinde oldukça fazla bu yazıyla ilgili mailler aldım, ancak aldığım son mailler bu yazıda kullandığım kodların, kullandığım veri kaynağı olan GADM platformunun paylaştığı veri içeriğini değiştirmesi nedeniyle istenilen sonucu vermediğine dairdi, o nedenle yıllar sonra bu içeriği güncellemek istedim. Bu içerikte de yine GADM de bu sefer JSON olarak paylaşılan verileri kullanarak bir Türkiye haritası oluşturacağız ve bir örnek üzerinden gradyan (gradient) renklendirmeler yapacağız.

Chat with LLMs on your R environment

3 minute read

Published:

LLM provides many advantages to the users, especially for coding. Once user had to switch the windows from the coding environment to the browser to search for the solution. But now, thanks to the newly advancements, users can chat with the LLM and get the solution for their queries on the same coding environment in R.

Segmented Total Bar Chart in R with ggsegmentedtotalbar

2 minute read

Published:

Kevin Flerlage, who is a data visualization specialist, suggested a great alternative to stacked bar plot on his blog. He called this new alternative “segmented total bar plot”. This R package ggsegmentedtotalbar implements this idea. The package is built on top of the ggplot2 package, which is a popular data visualisation package in R. The ggsegmentedtotalbar function creates a segmented total bar plot with custom annotations (boxes) added for each group. The height of each box is determined by the Total value associated with each group.

Election2023

Projects

portfolio

publications

Prediction of Earthquake Magnitude and Direction in Kütahya and Muğla using Machine Learning Methods

Published in 4th National Insurance and Actuary Congress, 2019

A machine learning study on predicting earthquake magnitude and direction in Kütahya and Muğla.

Recommended citation: Özdemir, O., & Yozgatlıgil, C. (2019). Makine Öğrenmesi Teknikleri ile Muğla ve Kütahya İllerindeki Deprem Büyüklüğünün ve Yönünün Tahminlenmesi. 4th National Insurance and Actuary Congress. https://www.researchgate.net/publication/360112382_Makine_Ogrenmesi_Teknikleri_ile_Mugla_ve_Kutahya_Illerindeki_Deprem_Buyuklugunun_ve_Yonunun_Tahminlenmesi

The impacts of COVID-19 lockdown on PM10 and SO2 concentrations and association with human mobility across Turkey

Published in Environmental Research, 2021

A study on how lockdown policies were associated with air pollution indicators and human mobility patterns across Turkey.

Recommended citation: Orak, N. H., & Ozdemir, O. (2021). The impacts of COVID-19 lockdown on PM10 and SO2 concentrations and association with human mobility across Turkey. Environmental Research, 197, 111018. https://doi.org/10.1016/j.envres.2021.111018. https://www.sciencedirect.com/science/article/pii/S0013935121003121?via%3Dihub

Evaluation of Reading Skills in the Context of Gender: An Analysis with PISA 2018 Data

Published in Education Reform Initiative (ERG), 2022

An analysis of reading skills in the context of gender using PISA 2018 data.

Recommended citation: Cin, M., Ilhan, A., Özdemir, O., Düşkün, Y., & Korlu, Ö. (2022). Okuma Becerilerinin Toplumsal Cinsiyet Bağlamında Değerlendirilmesi: PISA 2018 verileriyle bir analiz. Education Reform Initiative (ERG). https://doi.org/10.13140/RG.2.2.26165.35044 https://doi.org/10.13140/RG.2.2.26165.35044

Forecasting performance of machine learning, time series, and hybrid methods for low- and high-frequency time series

Published in Statistica Neerlandica, 2023

A comparative study of machine learning, classical time series, and hybrid methods for low- and high-frequency forecasting tasks.

Recommended citation: Özdemir, O., & Yozgatlıgil, C. (2023). Forecasting performance of machine learning, time series, and hybrid methods for low- and high-frequency time series. Statistica Neerlandica. https://doi.org/10.1111/stan.12326 https://onlinelibrary.wiley.com/doi/10.1111/stan.12326

turkeyelections: The Most Comprehensive Initial R Package Developed on Election Results in Turkey

Published in Journal of Statistics and Applied Sciences, 2024

An R package paper introducing turkeyelections, a comprehensive package for working with election results in Turkey.

Recommended citation: Özdemir, O. (2024). turkeyelections: The Most Comprehensive Initial R Package Developed on Election Results in Turkey. Journal of Statistics and Applied Sciences, 9, 67–76. https://doi.org/10.52693/jsas.1456233 https://dergipark.org.tr/tr/download/article-file/3810011

Forecasting Drought Phenomena Using a Statistical and Machine Learning-Based Analysis for the Central Anatolia Region, Turkey

Published in International Journal of Climatology, 2024

A statistical and machine learning-based study on forecasting drought phenomena in the Central Anatolia Region of Turkey.

Recommended citation: Türkeş, M., Özdemir, O., & Yozgatlıgil, C. (2024). Forecasting drought phenomena using a statistical and machine learning-based analysis for the Central Anatolia Region, Turkey. International Journal of Climatology. https://doi.org/10.1002/joc.8742 https://doi.org/10.1002/joc.8742

Leveraging Ensemble and Hybrid Forecasting Tools to Increase Accuracy: Turkey COVID-19 Case Study

Published in SN Computer Science, 2025

A forecasting study comparing ensemble and hybrid tools to improve prediction accuracy in a Turkey COVID-19 case study.

Recommended citation: Evkaya, O. O., Kurnaz, F. S., Ozdemir, O., & Yigit, P. (2025). Leveraging ensemble and hybrid forecasting tools to increase accuracy: Turkey COVID-19 case study. SN Computer Science, 6(2). https://doi.org/10.1007/s42979-025-03658-2 https://doi.org/10.1007/s42979-025-03658-2

From Perceptions to Evidence: Detecting AI-Generated Content in Turkish News Media with a Fine-Tuned BERT Classifier

Published in arXiv, 2026

A preprint on detecting AI-generated content in Turkish news media using a fine-tuned Turkish BERT classifier.

Recommended citation: Ozdemir, O. (2026). From Perceptions to Evidence: Detecting AI-Generated Content in Turkish News Media with a Fine-Tuned BERT Classifier. arXiv:2602.13504. https://doi.org/10.48550/arXiv.2602.13504 https://arxiv.org/abs/2602.13504

Türkiye’deki Açık Veri Kaynaklarına Genel Bakış ve Sosyal Bilimlerde Kullanımı: Ağaç Tabanlı Yapay Öğrenme Modelleriyle Seçim Sonuçlarını Etkileyen Ekonomik Göstergelerin Tahmini

Published in Sosyal Veri Bilimi: Programlama, Modelleme ve Sosyal Bilimlerde Dijital/Hesaplamalı Yöntemler, 2026

A book chapter on open data sources in Turkey and their use in social sciences, with an application of tree-based machine learning models to election-related economic indicators.

Recommended citation: Özdemir, O. (2026). Türkiye’deki Açık Veri Kaynaklarına Genel Bakış ve Sosyal Bilimlerde Kullanımı: Ağaç Tabanlı Yapay Öğrenme Modelleriyle Seçim Sonuçlarını Etkileyen Ekonomik Göstergelerin Tahmini. In H. Akın Ünver (Ed.), Sosyal Veri Bilimi: Programlama, Modelleme ve Sosyal Bilimlerde Dijital/Hesaplamalı Yöntemler. İstanbul Bilgi Üniversitesi Yayınları. https://bilgiyay.com/kitap/sosyal-veri-bilimi/

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