Ramaiah School of Public Health
Digital Health Lab · Learning resource

AI & infrastructure primer

The terms you will hear when building digital health tools, explained in plain language with public-health examples. From "what is an LLM" to "why did my server lose its data".

The big picture

How the AI terms fit inside each other

Each circle is a smaller part of the one around it. Every LLM is generative AI, all generative AI is deep learning, and so on. XAI is not a circle: it is a set of methods for explaining any of them.

Artificial Intelligence (AI) Any system doing tasks that need human-like judgement Machine Learning (ML) Learns patterns from data, e.g. predicting TB treatment dropout Deep Learning Many-layered neural networks, e.g. reading chest X-rays Generative AI Creates new text, images, audio LLM (large) SLM (small) XAI (explainable AI) Methods that explain why a model decided, e.g. SHAP, LIME Built on top of LLMs RAG · fine-tuning AI agents · chatbots local / private LLMs
AI terms

The AI vocabulary

Search any term. Each card has a plain definition and an example from our own work.

Side by side

Three ways to make an AI "know" our material

PromptingRAGFine-tuning
What it isWriting clear instructions and examples in the questionSearching our documents first, then letting the model answer from what it foundFurther training the model on our examples so it changes its behaviour
Best forQuick tasks, formatting, toneFacts that must be correct and cited: guidelines, syllabi, SOPsStyle and skill: writing MCQs our way, a consistent tutor voice
CostNoneLow: a vector database and some setupMedium: GPU time and a curated training set
UpdatingEdit the promptAdd or replace a document; instantRetrain
Our exampleVritta's minutes formatDiabot answering only from ICMR/RSSDI guidelinesPlanned: a public-health MCQ generator for Pariksha

Rule of thumb: use RAG for knowledge, fine-tuning for behaviour, and prompting always.

Infrastructure

How a web app actually runs

Every tool on our Innovations page follows this path. When something breaks, it breaks at one of these boxes.

Browser / app student's phone Domain + DNS pariksha.drhari.co.in Server Frontend (what you see) Backend / API (logic) Database marks, users, responses File storage PDFs, audio, images AI model (local or API)

The infrastructure vocabulary

Where to host

Local server, cloud server or free hosting?

OptionExamplesGood forWatch out for
Static hostingFirebase Hosting, GitHub PagesSites with no server code: this website, PRISM's pagesCannot run Python or keep a server-side database by itself
Platform-as-a-service (PaaS)Railway, RenderApps with a backend: Pariksha, Sangam, ArthaFree tiers sleep (slow first load) and may have no backups
Backend-as-a-serviceFirebase Firestore, SupabaseLogin, database and storage without running your own serverUsage-based bills; lock-in to one provider
Cloud virtual machineAWS, Azure, Google Cloud, Indian cloudsFull control, big workloads, GPUs by the hourYou manage security and updates; costs grow quietly
Local (on-premise) serverThe lab's DGX Spark and Mac mini serversSensitive data, private AI models, no monthly GPU rentNeeds power backup, IT network access, and your own backups
Builder's rules

Ten things every digital health builder should know

1. Back up everything, automatically

Follow the 3-2-1 rule: 3 copies, on 2 kinds of storage, 1 off-site. Free hosting tiers often keep no backup, so one wrong "reset" can erase exam results permanently.

2. Never put secrets in code

API keys and passwords go in environment variables or a secrets manager, never in GitHub. A leaked key can run up bills or expose data within hours.

3. Identifiable data needs a reason and a lock

India's DPDP Act 2023 applies to student and patient data. Collect the minimum, get consent, restrict access, and keep sensitive data off public AI services.

4. Own your accounts institutionally

Domains, app-store accounts and hosting should be under the institution, with two admins, so a tool never depends on one person's login.

5. Separate test from live

Try changes on a copy (a "staging" environment) before touching the live exam or portal.

6. Keep code in Git

Git records every change so you can undo mistakes. GitHub stores it online and lets others help.

7. Memory decides which AI model you can run

A model roughly needs (parameters × bytes per parameter) of memory. A 70B model at 4-bit needs about 40 GB before it answers a single question.

8. Validate before you trust

An AI tool is a health intervention. Test it against experts (as Diabot does) and report accuracy before real use.

9. Watch the free-tier limits

Free plans sleep, cap storage and change terms. Fine for demos; use a paid or institutional plan for anything students depend on.

10. A human approves every AI output

Minutes, MCQs, clinical answers: AI drafts, a qualified person checks and signs off.