docs: update dataset information and metadata

README.md

@@ -1,3 +1,33 @@
----
-license: ecl-2.0
----
+---
+license: ecl-2.0
+task_categories:
+- text-classification
+- feature-extraction
+language:
+- en
+tags:
+- public
+- text
+- tabular
+- education
+- multivariate
+- time-series
+pretty_name: Smartphone and Smartwatch Activity and Biometrics 15m6
+size_categories:
+- 1M<n<10M
+---
+
+# Smartphone and Smartwatch Activity and Biometrics 15m6
+
+A 15.6-million-sample, multi-device time-series corpus capturing 3-axis accelerometer and gyroscope readings from 51 volunteers. Each subject performed 18 activities for three minutes apiece while wearing both a smartphone and a smartwatch, yielding synchronized sensor streams sampled at 20 Hz.  
+
+Every record is formatted as:  
+
+- **subject-id** – unique identifier (1600–1650)  
+- **activity-code** – single-letter code A–S (excluding N) denoting one of 18 activities (e.g., walking, brushing teeth)  
+- **timestamp** – Unix epoch (seconds)  
+- **x, y, z** – raw sensor values for the given axis  
+
+The dataset is organized into four directories (phone-acc, phone-gyro, watch-acc, watch-gyro), each containing 51 per-subject files. Raw data plus 10-second sliding-window feature vectors are provided, enabling both activity-recognition and behavioral-biometric modeling.
+
+**Acknowledgements**: The dataset is hosted at the [UCI MLR—Smartphone and Smartwatch Activity and Biometrics](https://archive.ics.uci.edu/dataset/507/wisdm+smartphone+and+smartwatch+activity+and+biometrics+dataset)