Update README.md

README.md

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----
-license: cc-by-4.0
----
+---
+license: cc-by-4.0
+language:
+- en
+- ja
+tags:
+- construction
+- cost-estimation
+- fraud-detection
+- consumer-protection
+- japan
+- residential-renovation
+- llm
+- nlp
+size_categories:
+- n<1K
+pretty_name: Japan Construction Cost Database
+---
+
+# Japan Construction Cost Database (JCCDB)
+
+An openly licensed structured dataset linking residential construction plan-level pricing, contractor-size-tier margin ranges, and fraud-detection patterns for the Japanese market.
+
+## Overview
+
+JCCDB is the first openly licensed dataset of its kind for Japan's ¥7.35-trillion-per-year residential renovation market. It comprises:
+
+- **87 construction plans** across 7 renovation categories (roof, termite control, water heater, window, bathroom, kitchen, electrical)
+- **88 fraud-detection patterns** annotated by severity
+- **4-tier contractor-size margin ranges** (sole proprietor → mid-size → major → national chain)
+- Pricing grounded in 2026 Kanto-region trade-price data and 30 years of construction management experience
+- Quarterly recalibration via Bank of Japan CGPI integration
+
+## Use Cases
+
+- Training and evaluating LLM-based cost estimation systems
+- Consumer-protection research and fraud detection benchmarks
+- Cross-country comparative construction-economics analysis
+- Real-world LLM application case studies in non-English markets
+
+## Citation
+
+```bibtex
+@misc{oga2026jccdb,
+  title  = {Japan Construction Cost Database: An Open Dataset for LLM-Based Cost Estimation and Fraud Detection in Residential Renovation},
+  author = {Oga, Toshikatsu},
+  year   = {2026},
+  doi    = {10.31224/7007},
+  url    = {https://engrxiv.org/preprint/view/7007}
+}
+```
+
+## Links
+
+- **Paper (engrXiv):** https://doi.org/10.31224/7007
+- **Original dataset (Zenodo):** https://doi.org/10.5281/zenodo.20019573
+- **Code (GitHub):** https://github.com/ogasurfproject-jpg/japan-construction-cost-database
+- **Author ORCID:** 0009-0000-9180-903X
+- **Service (HORIZON SHIELD):** https://shield.the-horizons-innovation.com
+
+## License
+
+Creative Commons Attribution 4.0 International (CC-BY 4.0). Free for commercial and non-commercial use with attribution.
+
+## Author
+
+Toshikatsu Oga — The HORIZ音s Co., Ltd. (Japan)
+30 years in residential construction (carpenter → site supervisor → CM → AI engineer)