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casildata/README.md

Hi, I'm Javier Casildo 👋

Data Analyst and Data Scientist (M.S. Data Science) with a growing focus on security analytics. I work in Python, R, and SQL: cleaning and joining messy data, building models, and explaining results to people who need to act on them.

📍 Dallas, TX  ·  🎯 Seeking analytics, machine learning, and cybersecurity roles


About Me

I earned an M.S. in Data Science from Texas Tech University and a B.B.A. in Management Information Systems from Angelo State University.

Most of my work experience is in operations, where I learned to use data to fix real problems. At Frito-Lay, I owned raw-material forecasting and site-wide ordering; I also managed inventory analytics and accounting. Before that, I spent nearly seven years in a regulated medical-device environment (Johnson & Johnson MedTech), where I conducted root-cause investigations, supported CAPA initiatives, and kept records audit-ready.

My projects cover the full range of data work: ETL pipelines, SQL data warehouses, statistics, machine learning, and simulation. I'm applying many of those skills to cybersecurity, through hands-on simulation and private home labs with virtual machines. My projects are highlighted below and each repo lists its results alongside limitations.


Current Focus

  • 📊 Open to data analyst and data scientist roles
  • 📂 Publishing portfolio repos
  • 🛡️ Completing a Cyber Security Specialist program
    • CompTIA Security+, Linux+, and Cybersecurity Analyst (CySA+)
    • EC-Council Certified Ethical Hacker (CEH)
    • Systems Security Certified Practitioner (SSCP)
  • 🐍 Doing modeling work in Python and R

Technical Skills

Area What I've actually used it for
Python ETL with pandas, report automation, anomaly-flagging scripts at work, a mixed-integer optimization model
SQL Star-schema data warehouse with CTEs and window functions (SQLite, MySQL)
R ML classifiers (caret, glmnet, random forests), multivariate analysis, Monte Carlo and Bayesian models, simulation
Data Analysis Exploratory analysis, data cleaning and validation, KPI reporting, dashboards for non-technical audiences
Statistics Regression, hypothesis testing, PCA, clustering, factor analysis, Monte Carlo simulation
Machine Learning Classification, feature engineering, cross-validation, catching data leakage, choosing metrics that fit the problem
Cybersecurity VM labs with Nmap, Nessus, Wireshark, and DVWA; malware and malicious-domain detection; cyber risk quantification
Git / GitHub Version control, releases, and GitHub Actions CI on my published repos
Linux Shell basics and working with log files (Cisco Networking Academy)
VS Code My main editor for Python work

Technologies & Tools

Languages: Python · SQL · R
Data & ML: pandas · NumPy · SciPy · tidyverse · caret · Jupyter
Databases: SQLite · MySQL
Visualization: Tableau · Qlik · Power BI (working knowledge) · Excel · matplotlib · ggplot2
Security (course labs and training): Nmap · Nessus · Wireshark · DVWA
Workflow: Git · GitHub Actions · VS Code · Linux shell · pytest · testthat

Python pandas R SQL Tableau Git GitHub Actions Linux VS Code


Featured Projects

Some projects started as Texas Tech graduate coursework and were rebuilt to run from a clean clone. Each project comes with results, limitations, and improvement opportunities.

Data Analysis & Data Modeling

Project What it does Key result
covid-social-media-etl-pipeline Python ETL that joins four public datasets with mismatched keys, grains, and date formats; drops PII before aggregation Cases and reported anxiety moved together over 27 periods (r = 0.80, not causal); 2026 refactor matches the original outputs exactly
nba-star-schema-data-warehouse Star-schema warehouse with an ETL pipeline, data-quality checks, and 8 analytic SQL queries Rejects all 3 planted corrupt rows; 8/8 tests pass

Data Science & Machine Learning

Project What it does Key result
malware-dns-threat-detection-ml Classifies malware from memory-forensics features and flags malicious domains from DNS name features Malware: 99.4–100% recall on families held out of training. Domains: 17–33% recall at a 1% false-positive budget, with a write-up of why
email-spam-detection-ml Compares five classifiers and an ensemble for spam filtering Random forest 94.95% accuracy; found and fixed a data-leakage bug in the kNN model
wine-quality-multivariate-analysis PCA, clustering, outlier detection, and discriminant analysis on 6,497 wines k-means separates red from white with 98.6% agreement; fixes an outlier-rule bug in the original coursework

Simulation, Optimization, & Risk

Project What it does Key result
cyber-risk-monte-carlo Monte Carlo model of annual cyber losses, with control ROI and a Bayesian rate update Loss exceedance curve, ROI with uncertainty per control, one-page brief for leadership
soc-alert-triage-simulation Discrete-event simulation of a two-tier security operations team One more tier-2 analyst cuts confirmed-incident wait from 33.9 to 4.4 minutes
security-budget-optimizer Mixed-integer program that chooses the security controls that remove the most expected loss for a budget Verified optimal against all 262,144 combinations

Security Labs

Project What it does Key result
security-labs-writeups Five course lab write-ups: vulnerability scanning, packet analysis, PKI, web attacks, and host hardening Coming soon

Certifications & Training

Credential Issuer Date
Cyber Security Specialist Program TopTalent Learning In progress
Operating Systems Basics Cisco Networking Academy Oct 2026
Computer Hardware Basics Cisco Networking Academy Sep 2026
Python for Data Science and AI IBM Jun 2023
PCEP – Certified Entry-Level Python Programmer OpenEDG Python Institute Jul 2022
QMS Internal Auditor training (ISO 9001 / ISO 13485) Exemplar Global-certified course Jan 2020
Network Pro Certification TestOut May 2019

Education

Study Institution Date
Master of Science, Data Science Texas Tech University, Lubbock, TX May 2022
Certificate in Applied Statistics Angelo State University, San Angelo, TX Dec 2020
Bachelor of Business Administration, Management Information Systems (Cum Laude) Angelo State University, San Angelo, TX Dec 2019

Let's Connect

I'm open to data analyst, data scientist, and entry-level security roles, and I'm glad to talk with people working in any of those areas.

LinkedIn Email

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  1. malware-dns-threat-detection-ml malware-dns-threat-detection-ml Public

    Threat detection in R: obfuscated malware from memory-forensics features (CIC-MalMem-2022) and malicious domains from lexical DNS features (CIC-Bell-DNS-2021)

    R