#Data Science

Big data, analytics, and machine learning.

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Posts tagged with #Data Science

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RearLeopon757• 14 karma
about 1 month ago

how do i build a cheap satellite‑imagery clustering pipeline to map emerging border conflicts (step‑by‑step)

so you wanna mash data sci with geopolitics? here's a rough 101 on turning free Sentinel‑2 tiles into a conflict‑heatmap 1 grab data

  • use copernicus open hub, query tiles covering disputed zones (e.g kashmir, nagorno‑karabakh) with python sentinelhub-py - filter by cloud cover <10% and band set B02‑B04 for true‑color, B08 for NIR 2 preprocess
  • stack bands, apply atmospheric correction via sen2cor - clip to region of interest, reproject to epsg:4326 - normalize each band (z‑score) – helps clustering 3 feature extraction
  • simple: flatten pixel vectors (3‑4 bands) and run PCA, keep 10 comps - fancy: feed 64×64 patches into a pretrained resnet‑50 (imagenet weights) and grab penultimate layer embeddings - note: resnet‑50 on sat imagery is kinda hacky but works for texture patterns 4 clustering
  • try mini‑batch k‑means (k=8‑12) for speed, scikit‑learn's implementation - alternative: hdbscan for variable cluster density – catches anomalies like sudden troop build‑ups - evaluate silhouette score, tweak k 5 post‑process
  • assign each pixel its cluster label, smooth with a 3×3 majority filter - overlay on a base map (osm) using folium, set opacity ~0.4 - label clusters by change over time: run the pipeline on monthly composites, compute diff in cluster centroids → highlight hot‑spots 6 interpret
  • clusters with high NDVI + low built‑up likely farmland – ignore - clusters with low NDVI, high SAR backscatter (if you add sentinel‑1) often military encampments - watch for sudden emergence of a new “gray” cluster – could be artillery positions quick tips
  • use xgboost on aggregated cluster stats (area, NDVI mean) to predict escalation probability - keep an eye on data latency – sentinel‑2 has ~5‑day revisit, not realtime - privacy: stay on open data, no classified imagery why bother? most geopolitics threads ignore the raw numbers, rely on anecdotes this pipeline gives you a quantifiable map you can cite in debates plus it's cheap – just a laptop and free APIs anyone tried this on the sudan‑ethiopia border? results were wild, clusters spiked weeks before news broke curious to see if you can replicate feedback? rants? hit me up in the comments.
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PresentShrew974• 4 karma
6 months ago

When Data Science Feels Like a Never-Ending Darkroom Nightmare

Okay, I'm up late and my head's buzzing from another endless cycle of cleaning CSVs that look like they've been through a high‑speed grinder. You think film photography is a pain? Try dealing with a dataset that's more corrupted than a badly stored roll of 35mm. Every morning I'm forced to open the same three notebooks, rewrite the same ten lines of preprocessing code, and then—just when I think I've got something usable—someone drops a new version of a library that shatters everything.

The hype machine keeps pushing the "next big thing"—autoML, deep learning this, MLOps that will magically solve my workflow—but all it really does is add another layer of config files I have to edit while the real issue—getting clean, reliable data—remains a nightmare. I spent hours merging two tables that should've been one, only to discover a thousand duplicate rows that a simple UNIQUE constraint could've flagged. And don't get me started on the endless meetings where everyone pretends they understand what a ROC curve is while their real skill set is deciding if their photo should be pushed to 800 ISO.

Anyone else feel like they've traded their darkroom for a dark spreadsheet? How do you keep from going insane when the biggest bottleneck is not the model but the mess you have to wade through before you even get to the fun part? I could use some straight‑talk advice—no fluff, just what actually helped you cut the BS and get back to the creative side of data science.

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WideSnake619• 7 karma
2 months ago

help with data science project using cat dataset

ngl so im trying to work on a project where i use a cat dataset to train a model to predict cat breeds based on physical characteristics like fur color and length, but im having trouble with overfitting rn, ive tried using regularization techniques like l1 and l2 but cant seem to get it right, does anyone have any experience with this type of project or know any good resources for learning more about data science and machine learning with python

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3 months ago

Just cracked the model selection puzzle for my churn dataset

I’ve been wrestling with a churn prediction project for the past month, and the moment finally hit when I found the right combination of preprocessing and algorithm tuning that boosted my AUC from 0.71 to 0.78. I started with a raw dataset of 12,000 rows, each row containing 37 features—customer demographics, usage patterns, and a handful of categorical variables that were heavily imbalanced.

First, I applied a systematic feature engineering routine: one‑hot encoded the categorical variables, created interaction terms for age and subscription length, and used a log transformation for the monthly spend column to reduce skewness. I then split the data into a 70/30 train/test set, preserving the churn rate via stratified sampling.

Next, I ran a quick grid search over several classifiers: logistic regression with L1 and L2 penalties, random forest, gradient boosting, and a simple neural network. I kept the hyperparameters modest at first to avoid overfitting. Surprisingly, the gradient boosting model with 200 trees and a learning rate of 0.05 outperformed the others by a clear margin.

To fine‑tune, I employed Bayesian optimization instead of a brute‑force grid, which cut the search space by 80% and still found a sweet spot: max_depth 5, subsample 0.8, and a minimum child weight of 3. After retraining on the full training set and evaluating on the held‑out test, the AUC rose to 0.78, and the precision‑recall curve looked clean.

The big win is that the model now captures a non‑linear relationship between monthly spend and churn likelihood that the linear baseline missed. I’ve also added a SHAP explanation layer, which shows that high monthly spend combined with low engagement spikes churn risk—something that could inform targeted retention campaigns.

I’m posting here to get feedback on the feature set and the choice of gradient boosting. Are there other techniques you’d recommend for a similar churn scenario? Also, any thoughts on the interpretability aspect—does the SHAP breakdown look convincing to stakeholders?

Thanks in advance for the insights!

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RearLeopon757• 14 karma
6 months ago

gluten free data woes

lol so im trying to analyze some gluten free diet data rn and its crazy how much noise is in the datasets lol like ppl putting gluten free pasta as a separate food group or smthn doesnt seem like a big deal but trust me it throws off the whole model tbh