What the Data for This Category Looks Like
The data sources for railway and highway investment research include official road network operation monthly reports, infrastructure project completion archives, freight dispatch daily reports, freight rate adjustment announcements, line technical parameter documents, and more. Update cycles cover daily (dispatch, freight volume), monthly (operation reports), quarterly (infrastructure progress), and annual (industry summaries). Document structures include structured business tables (with fields such as line mileage, freight volume, toll rates), long-text analysis reports, and policy notification documents. Field units are typically kilometers, ten thousand tons, yuan/ton-kilometer, service life, and similar units, with no unified short-text format.
Constraints Imposed on Knowledge Base Retrieval and Recall
The multi-dimensional update cycles of railway and highway investment research data require retrieval systems to support incremental updates across different cycles. This avoids excessive system load caused by full updates. The mixed document structure of structured business tables and long text requires retrieval systems to support both semantic retrieval and structured field retrieval. This prevents loss of logical association caused by splitting titles and subordinate content. Unique business fields and units require recall results to fully retain metadata unit information. Missing this information will reduce the accuracy of investment research judgments. Strong data correlations (such as line connections, freight flow directions) require retrieval results to include associated metadata. This allows quick verification of information accuracy.
Configuration Settings
| Configuration Item | Recommended Value | Rationale |
|---|---|---|
recall count | Top 8-12 entries | Single chunk information for railway and highway investment research is relatively large. Too many recall entries increase information filtering costs |
similarity threshold | 0.72-0.85 | It is necessary to distinguish between professional terms and general expressions. A threshold that is too low will include irrelevant data, while a threshold that is too high will omit valid content in specific scenarios |
chunk segmentation length | 1000-1500 characters | Balances the logical integrity of long reports and retrieval accuracy, and avoids splitting titles and subordinate line parameter content |
incremental update trigger interval | Every 12 hours | Matches the update cycles of daily and monthly operation data, balancing real-time performance and system load |
metadata retention fields | line_name, cargo_volume, unit_price | Retains core business fields unique to railways and highways, to facilitate associated display of complete information after retrieval |
reranked return count | Top 3-5 entries | Focuses on the most relevant core data, avoiding information overload |
The parameter values provided on this page are conventional recommendations used to establish a starting point for configuration. Actual values are affected by material form, data volume, and business rules. Specific issues require individual analysis. It is recommended to test on samples matching the specific deployment before finalizing the configuration.
Three Common Mistakes
- Phenomenon: Retrieval results only return chunk text, and associated metadata such as line name and freight volume is empty. Cause: The
metadata retention fieldsconfiguration is not set, or metadata association rules are not bound in the retrieval logic. - Phenomenon: Markdown-formatted road network planning documents are split into different chunks during segmentation. Titles and subordinate line parameter content cannot be matched for complete logic during retrieval. Cause: The
chunk segmentation lengthis set too short, and the association boundary between titles and subordinate content is not retained. - Phenomenon: Extra spaces appear between freight volume numbers and units in retrieval results. Cause: Original typesetting character spacing is not retained during document parsing, or number and unit fields are not automatically merged in recall results.
How to Confirm Correct Configuration
- Upload a railway operation report containing a structured table, and verify that retrieval results return both chunk text and the configured metadata fields.
- Submit a markdown document with multi-level titles, and check that titles and corresponding content appear in the same recall result after retrieval.
- Import a freight data document containing numbers and units, and confirm that no extra spaces exist between numbers and units in retrieval results.
- Trigger an incremental update task, and verify that updated data is normally displayed in retrieval results.
Question material comes from public community discussions. Configuration values are common starting points and should be measured against your own samples. Verified on 2026-09-14.