Alex Petrov

General 9 min

Alex Petrov • 3 days ago

Running a Mid-Cohort AI and Plagiarism Sweep on 300 Submissions

A week-by-week account of the three-signal sweep one bootcamp runs at week 7 of every cohort: peer similarity, web matching, and AI detection in one batch. Includes the ignore-list mistake that cost us two evenings, what LLM-shaped student code actually looks like, and how to turn a flag into a conversation instead of a verdict.

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General 10 min

Alex Petrov • 5 days ago

How One Bootcamp Screens 400 Take-Homes for AI Code

387 files, three scores, one hiring round. Here's what a 12-week bootcamp learned after moving take-home review from three exhausted instructors to an automated pass that checks peer similarity, public web sources, and AI generation, including the false positives we cleared and the two assignment changes that mattered more than any detector.

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General 15 min

Alex Petrov • 1 week ago

Can a Python Submission Be Traced Back to a Java Repository?

Two Python submissions scored 4% against each other and in the 70s against a Java gist from 2017. Cross-language plagiarism is the fastest-growing blind spot in academic integrity because translation destroys the text while preserving everything that matters. Here's what survives a translation, what detectors actually see, and where the false positives come from.

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General 13 min

Alex Petrov • 2 weeks ago

How Cross-Language Code Plagiarism Detection Works

A Java submission and a Python submission looked nothing alike, but they were the same algorithm translated line by line. This is the story of how cross-language code plagiarism detection actually works, where it catches translated code, and where it still fails.

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General 10 min

Alex Petrov • 2 weeks ago

Designing Coding Assignments That AI Can't One-Shot

As a bootcamp instructor, I've graded hundreds of take-home coding challenges. The AI-resistant ones share a pattern: they ask for process artifacts, not just final code. Here's how to design assignments that hold up.

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General 6 min

Alex Petrov • 3 weeks ago

The Long Road to Refactoring-Resistant Code Plagiarism Detection

A hands-on retrospective on how code similarity detection grew from naive line diffs to tokenization, ASTs, and fingerprinting. Follow a step-by-step Python prototype and a production workflow with Codequiry to catch refactored plagiarism in CS courses.

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General 9 min

Alex Petrov • 1 month ago

How to Detect Code Copied From Online Sources in Student Submissions

A bootcamp instructor walks through the exact workflow he uses to catch student code copied from tutorials, GitHub repos, and Stack Overflow answers, including what peer-only checkers miss, how to read web match reports without false positives, and where Codequiry fits.

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General 10 min

Alex Petrov • 1 month ago

From Manual Google Searches to Automated Stack Overflow Code Detection

Quoted Google searches used to be the standard way to catch a Stack Overflow lift. I tracked the shift across tools, fingerprints, and live web corpora, and why modern checks need to pair source matching with AI detection. The short version: the web changed the question from "who copied whom" to "where did this code come from."

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General 8 min

Alex Petrov • 1 month ago

How Token-Based Fingerprinting Drives Contractor Code Verification

A logistics company needed to know whether a contractor's 14,000-line Python service was original before paying the final invoice. Token-based fingerprinting showed exactly how much had been lifted from an open source repo and rewritten just enough to hide. What the team learned about normalization, thresholds, and the limits of similarity scoring applies to any company that accepts outside code.

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General 10 min

Alex Petrov • 1 month ago

What 238 License Violation Tickets Taught Me About Open Source Compliance

As a bootcamp instructor and open-source maintainer, I've closed hundreds of license-related pull requests. Most were copy-paste fixes where someone dropped a Stack Overflow function into a GPL project. This walks through what actually triggers license tickets, which scanners catch what, and where source similarity tools save you from silent compliance failures.

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General 10 min

Alex Petrov • 1 month ago

What 2,312 CS1 Python Submissions Revealed About Code Copied

A direct walkthrough of a Python code plagiarism audit across three bootcamp cohorts. Learn which thresholds actually caught copied code, why starter-code exclusion matters, and how to stack web and AI detection into one honest review pass.

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General 9 min

Alex Petrov • 1 month ago

Perplexity Thresholds for Detecting AI Code

A bootcamp instructor explains how token-level perplexity works as an AI code signal, what thresholds we actually use in Java review, and why a single statistical score is never enough on its own.

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