On-Premises Multi-Course RAG Tutoring for Business Education: Hardware-Software Trade-offs in a Campus AI Tutor
Organizations: Dhillon School of Business, University of Lethbridge
Abstract
Campus AI tutors based on retrieval-augmented generation (RAG) must ground answers in assigned course materials while keeping textbooks and student dialogue on institutional infrastructure. We present CourseChat, an on-premises, multi-course RAG tutor for undergraduate business education, deployed behind a campus web gateway and intended for use embedded in Moodle. Six isolated course offerings, each keyed by its own course reference number (CRN), share twin-edge AI hosts running a FastAPI service, a local vector database, and a local large language model (LLM) served by Ollama. We report two generation-model bake-off rounds, a separate fixed-evidence source-fidelity comparison, and conversation and quiz audits. Several larger models failed the classroom speed gate, but a 12B model and a 7B alternative passed. A separate mixture-of-experts candidate improved some corrections while introducing new factual and continuity errors. We therefore retain the 8B production model pending a demonstrated overall improvement, rather than claiming that 8B is universally optimal. Software changes improved follow-up topic resolution while preserving course scope; 435 prebuilt questions across 65 modules decouple practice from live generation. The results support treating model choice, evidence selection, serving compatibility, and product design as a joint engineering decision. They do not establish learning gains: faculty ratings, peak-load capacity, and complete public-gateway acceptance remain separate evaluation needs.
Figures & tables
| Approach | Observed result | Trade-off | Decision |
|---|---|---|---|
| Larger dense generators (first round) | All passed 12/12 live probes; median completion times were 1.75–3.36 times the 8B baseline. | Some answers were more complete, but every candidate exceeded the classroom latency limit. Probe passes alone do not establish pedagogical quality. | Retain 8B for classroom service. |
| Qwen 7B and Mistral Nemo 12B | Both passed 12/12 probes; latency ratios were 1.01 and 1.24. Qwen completeness was 0.93 versus 0.91 for 8B. | Both met the speed gate. Speed passes and small completeness differences did not establish a faculty-reviewed tutoring advantage. | Retain as candidates for paired review. |
| Structured Qwen mixture-of-experts response | Warm median was 3.00 s versus 3.47 s for 8B, but review found three regressions across twelve fixed-evidence cases. | Faster warm responses and better corrections accompanied a new factual error and an unnecessary refusal. Model and response contract changed together. | Hold activation. |
| Deterministic follow-up resolution | Topic checks rose from 23.3–40.0% in baseline resolver preflight to 90–100% live across five courses; all 400 scope checks passed. | Better continuity required no generator change. Correct topic selection and scope do not by themselves verify answer fidelity. | Deploy resolver with 8B. |
| Prepared quiz banks | 435 questions cover 65 modules. Warm practice-request medians were 4.8 and 5.8 ms on the two nodes. | Inspectable evidence and deterministic grading require finite banks, maintenance after source changes, and instructor review. | Serve prepared banks; faculty approval remains pending. |
| Model | Live eval | p50 (ms) | vs. 8B | Speed gate |
|---|---|---|---|---|
| llama3.1:8b (prod.) | 12/12 | 8392 | 1.00 | pass |
| qwen2.5:14b-instruct | 12/12 | 14726 | 1.75 | fail |
| gemma3:12b | 12/12 | 18855 | 2.25 | fail |
| qwen3:14b | 12/12 | 28194 | 3.36 | fail |
| qwen3.6:35b-A3B (Q4) | 0/12 | 15109 | 1.80 | fail † |
| Model | Live eval | p50 (ms) | vs. 8B | Speed gate |
|---|---|---|---|---|
| llama3.1:8b | 12/12 | 8556 | 1.00 | pass |
| qwen2.5:7b-instruct | 12/12 | 8668 | 1.01 | pass |
| mistral-nemo:12b | 12/12 | 10589 | 1.24 | pass |
| ibm/granite3.3:8b | 0/12 | 21443 | 2.51 | fail ‡ |
| Offering | Baseline | Updated live | Updated rate | Scope |
|---|---|---|---|---|
| Course 1 | 31/60 | 60/60 | 100.0% | 80/80 |
| Course 2 | 24/60 | 54/60 | 90.0% | 80/80 |
| Course 3 | 22/60 | 55/60 | 91.7% | 80/80 |
| Course 4 | 17/60 | 58/60 | 96.7% | 80/80 |
| Course 5 | 14/60 | 59/60 | 98.3% | 80/80 |
| Course 6 | 19/60 | 60/60 | 100.0% | 80/80 |
AI in Education
AI in Education studies how artificial intelligence can support teaching, learning, assessment, and educational decision-making.
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