prodopsy # Postmortem: Biased Model Training with EEG Signals ## Persistent model bias observed during training on EEG dataset for wheelchair navigation commands: – Models consistently best identified `stop/neutral` → moderately performed on `forward/left` → consistently failed on `right` – Observed across MATLAB Classification Learner models and custom – Best outcomes: ~50% accuracy for problematic classes … Read more
# The Cache Miss Illusion: When Out-of-Order Execution Masks Real ## We investigated the misconception that cache misses consistently cause severe pipeline stalls in out-of-order (OOO) CPUs. While cache misses do incur latency, OOO execution often hides this cost by continuing unrelated work—misleading profiling tools and engineers into misidentifying optimization targets. ## Root – **Misinterpretation … Read more
# Postmortem: Performance Bottleneck in Repeated Python Function Calls from ## A performance-critical data processing pipeline experienced significant slowdowns when integrating Python-calculated variables into an R dataframe using reticulate and dplyr. The implementation repeatedly called the same Python function 7 times per group to extract individual output elements, leading to unnecessary computation. ## Root – … Read more
# Postmortem: Unstable Clock Signal in JK Flip-Flop LED ## When constructing a JK flip-flop clock circuit with an LED indicator, the LED blinks at ~0.5-second intervals despite unclear logic. Analysis reveals unstable clock triggering due to unintended button behavior causing erratic state transitions. ## Root – **Contact bounce**: Physical push buttons generate electrical noise … Read more
# Technical Postmortem: Overcoming Limitations in VS Code Syntax Highlight ## Our team encountered challenges while creating a custom VS Code theme when attempting to modify syntax highlighting colors for specific Python constructs (e.g., method calls like `classInstance.compute()`). The primary pain point was identifying the correct TextMate scopes due to ambiguous naming conventions, language-specific scope … Read more
# Python Script Crashes After One Hour: Spotify Token ## – A Python script using the Spotipy library unexpectedly crashes after approximately one hour of runtime. – The crash occurs because Spotify access tokens expire after **60 minutes** per Spotify API policy. – Without token refresh logic, subsequent API calls fail once the token expires, … Read more
# Using setTimeout() instead of step.sleep() in a Cloudflare Workflow? ## Summary A workflow relied on Cloudflare K/V writes with a strict rate limit (1 write/sec per key) after each API call. Initial mitigation used `step.sleep()` to avoid throttling, but the engineer explored substituting it with `setTimeout()` to simplify step architecture. Replacing the native sleep … Read more
Postmortem: Misunderstanding Android 9 Update Eligibility Leading to Security Risks Summary Users attempted to upgrade Android 9 devices to Android 10/11 and locate security patches without success. Root cause analysis revealed unsupported hardware, fragmented OEM policies, and discontinued security updates for legacy devices. Root Cause Hardware Compatibility: Older devices lack drivers/capabilities for newer OS versions. … Read more
Azure AD B2C Session Management: Preventing User Creation After Abrupt Session Closure Summary Azure AD B2C unexpectedly creates user profiles if a session terminates abruptly after users submit signup information. Occurs specifically during the final signup stages (e.g., post-submit/continue click), leaving the user journey incomplete. Impacts systems relying on custom policies that trigger user creation … Read more
Cant Serialize and Deserialize ViT in Keras When Setting Classification = True Summary Attempts to serialize (save) or deserialize (load) the ViT Keras model fail exclusively when classification=True Models saved with classification=False work correctly Error arises during deserialization when reconstructing the model architecture Common error: AttributeError indicating cls_token is missing upon loading Root Cause The … Read more