Glossary
Plain English for the terms in the talks. Six groups, in story order. Jump, or read top to bottom and the picture builds.
The model
What a language model is, how it reads, and where it goes wrong.
LLM (Large Language Model)
The AI that reads text and generates responses. "Large" because these models have billions of parameters (adjustable settings) learned from massive amounts of text. Examples include Llama, Mistral, and Qwen. We run ours locally on Faculty hardware.
Token
The basic unit an AI model reads and writes. Roughly a word or a piece of a word. "Dentistry" is one token. "Faculty of Dentistry" is about four. Models have a context window measured in tokens, which limits how much text they can process at once.
Inference
The act of an AI model generating a response. When you ask a question and the AI answers, that's inference. In our system, inference happens locally on Faculty hardware, not on some server in another country.
Hallucination
When an AI confidently generates information that sounds right but is completely made up. A fine-tuned model might invent an email address that doesn't exist or cite a form that was never created. RAG reduces this by giving the AI real documents to read before answering.
What we tried first
Teaching the model our policies by retraining it. This is the Failed Runs path. It did not hold facts.
Fine-Tuning
Retraining an AI model on your own data so it absorbs new knowledge permanently. Like trying to teach someone a textbook by having them memorize it. Works well for learning a writing style, but unreliable for learning specific facts unless you repeat each fact hundreds of times.
LoRA (Low-Rank Adaptation)
A technique for fine-tuning that only changes a small fraction of the model's parameters instead of all of them. Makes fine-tuning faster and cheaper, but doesn't solve the fundamental problem of the model inventing facts it was supposed to learn.
RAFT (Retrieval Augmented Fine-Tuning)
A hybrid approach from Microsoft that combines fine-tuning with RAG-style training data. The model learns to answer questions by reading provided documents rather than memorizing facts. Promising in research, but we found pure RAG simpler and effective enough for our needs.
How retrieval works
Search the files first, then let the model read. Open-book instead of memorization.
RAG (Retrieval Augmented Generation)
Instead of teaching the AI your facts, you search your documents first and paste the relevant passages into the prompt. The AI reads them on the spot and answers from what it just read. Like an open-book exam instead of memorization. This is the core technique behind RAG Proxy.
Chunking
Splitting a long document into smaller pieces (usually a few paragraphs each) so the AI can search through them efficiently. Think of it like cutting a textbook into index cards. Each card is small enough to find quickly but big enough to still make sense on its own.
Embedding
Turning text into a list of numbers that captures its meaning. Similar sentences get similar numbers. This is the magic that lets the system understand that "needlestick protocol" and "what to do after getting poked by a needle" are asking about the same thing.
Vector
A list of numbers that represents a piece of text in mathematical space. Each number captures some aspect of meaning. Vectors that are close together represent text with similar meanings. Our bge-m3 model produces vectors with 1,024 dimensions.
Vector Database
A storage system optimized for saving and searching vectors. Ours is simple: SQLite for the text and metadata, PDL matrices for the vector math. Big companies use specialized databases like Pinecone or Weaviate, but for 94 documents, SQLite is more than enough.
Cosine Similarity
A math formula that measures how similar two things are by comparing the angle between their vectors. A score of 1.0 means identical, 0.0 means completely unrelated. It's how the system decides which document chunks are most relevant to your question.
Semantic Search
Finding documents based on meaning rather than exact keywords. Traditional search requires you to guess the right words. Semantic search understands that "infection control after needle incident" matches a document titled "Sharps Injury Protocol" even though the words are different.
Our system
The middleman, one knowledge domain per brain, then the later checks: inject a cheat sheet, then verify the answer.
RAG Proxy
The local AI middleman we built. It sits between the chat interface and the language model. Every question gets enriched with the right policy excerpts before the AI sees it, so the AI answers from real documents instead of inventing things. Speaks the usual chat APIs, so any chat client can use it.
Brain
A self-contained knowledge domain. One brain holds the dental policies; another could hold HR, IT, or library docs. Each brain is a folder with a SQLite database, a vector matrix, and the source documents. Knowledge stays compartmentalized, so the dental brain never accidentally answers HR questions.
Pin
A cheat sheet the proxy injects when a question matches a topic. Search still runs. The pin is there even if search grabbed the wrong file. This is not a search ranking score. Came after the first public code snapshot.
Harness
Software that checks the answer after the model talks. For clinic policies it checks numbers against the real list. If the model invents a policy number, that fails and it has to redo the answer. The model cannot talk its way past the check. Came after the first public code snapshot.
The stack
What actually runs on Faculty hardware. The May snapshot talked to a laptop engine. Production does not.
DGX Sparks
Two NVIDIA boxes in the Faculty. One is the front door (chat, proxy, embeddings). The other runs generation. Clinic answers stay on premises. This replaced the laptop Ollama path.
Ollama
A local model runner the May snapshot used. The proxy can still speak that API so old chat clients work. Production generation is on the Sparks, not this.
PDL (Perl Data Language)
Used in the search library for vector math (cosine similarity). An implementation detail of Brain.pm, not the product pitch.
Why it stays on campus
The legal reason this is not a cloud chat app.
PHIPA
Personal Health Information Protection Act. Ontario legislation that governs how health information custodians handle patient data. Sending patient-adjacent queries to cloud AI services would create compliance risk, which is why everything stays on-premises.
FIPPA
Freedom of Information and Protection of Privacy Act. Ontario legislation that governs how public institutions (like universities) collect, use, and disclose personal information. One of the key reasons we built a local AI system instead of using a cloud service.