> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cronozen.com/llms.txt
> Use this file to discover all available pages before exploring further.

# LMS Platform

> White-label LMS SaaS for HRD-Net compliant remote training and workshop management

# LMS Platform

Cronozen LMS (`learn.cronozen.com`) is a white-label learning management system designed for Korean workforce development institutions. It provides HRD-Net regulatory compliance, electronic monitoring (EMON), and DPU-based attendance proof — all integrated with the Cronozen OPS hub.

## Product Lineup

<CardGroup cols={2}>
  <Card title="Remote Training LMS" icon="laptop">
    HRD-Net compliant online courses for government-subsidized programs (내일채움카드). Includes EMON integration, anti-fraud protections, and automated compliance reporting.
  </Card>

  <Card title="Workshop Management" icon="users">
    Offline seminar and workshop management with QR check-in, DPU attendance proof, capacity management, and location tracking.
  </Card>
</CardGroup>

***

## Architecture

```
┌──────────────────────────────────────────────┐
│                  OPS Hub                      │
│        (auth.cronozen.com / SSO)             │
│   ┌─────────┬──────────┬──────────┐          │
│   │  Auth   │  Billing │   DPU    │          │
│   │  (JWT)  │  (Toss)  │ (Proof)  │          │
│   └────┬────┴────┬─────┴────┬─────┘          │
└────────┼─────────┼──────────┼────────────────┘
         │         │          │
┌────────▼─────────▼──────────▼────────────────┐
│              LMS Spoke                        │
│        (learn.cronozen.com)                   │
│                                               │
│   ┌─────────┐  ┌──────────┐  ┌───────────┐  │
│   │ Learning │  │ Workshop │  │   EMON    │  │
│   │ Engine   │  │ Attend.  │  │ Reporter  │  │
│   └─────────┘  └──────────┘  └───────────┘  │
│                                               │
│   ┌─────────┐  ┌──────────┐  ┌───────────┐  │
│   │  HRD    │  │  Fraud   │  │   QR      │  │
│   │ Comply  │  │ Detect   │  │ Check-in  │  │
│   └─────────┘  └──────────┘  └───────────┘  │
└───────────────────────────────────────────────┘
```

### Hub-Spoke Integration

| Component            | Responsibility                     | Service |
| -------------------- | ---------------------------------- | ------- |
| SSO Authentication   | JWT issuance, actor identity       | OPS     |
| Billing & Payments   | Toss Payments, subscription        | OPS     |
| DPU Attendance Proof | SHA-256 hash chain sealing         | OPS     |
| Learning Engine      | Course delivery, progress tracking | LMS     |
| EMON Reporting       | Government monitoring transmission | LMS     |
| Fraud Detection      | Anti-cheating, device fingerprint  | LMS     |

***

## Multi-Tenant Structure

Each training institution is a **tenant** with isolated data, branding, and configuration.

```
Tenant: seocho-women-center
├── subdomain: seocho.learn.cronozen.com
├── centerId: 2 (OPS center mapping)
├── features: { hrdEnabled, emonEnabled, ... }
├── Products (courses, workshops)
├── Registrations (enrollments)
├── Progress (learner tracking)
└── Assessments (exams, assignments)
```

### Tenant Configuration

Tenant-specific settings are stored in the `Configuration` table:

```json theme={null}
{
  "hrdEnabled": true,
  "hrdPassingScore": 60,
  "hrdMinProgressPercent": 50,
  "hrdMaxDailyLessons": 8,
  "emonEnabled": true,
  "emonApiUrl": "https://emon.hrd.go.kr/api/v1",
  "emonInstitutionId": "INST-001"
}
```

***

## HRD-Net Compliance

### Regulatory Requirements

HRD-Net (Korea Human Resources Development Service) mandates specific controls for government-subsidized remote training. Non-compliance can result in funding suspension.

### Core Rules

| Rule                  | Requirement                                     | Implementation              |
| --------------------- | ----------------------------------------------- | --------------------------- |
| **Learning Activity** | 10-second heartbeat tracking                    | `heartbeat-service.ts`      |
| **Daily Limit**       | Max 8 hours / 8 lessons per day                 | `lesson-unit-service.ts`    |
| **Completion**        | 80% progress + 60-point score                   | `hrd-completion-service.ts` |
| **Sequential**        | Lessons must be completed in order              | Lesson unlock gates         |
| **Assessment**        | 3 types: progress check, final exam, assignment | `hrd-assessment-service.ts` |
| **Identity**          | Phone OTP verification (본인인증)                   | mOTP adapter                |
| **Monitoring**        | EMON API data transmission                      | `emon-adapter.ts`           |

### Learning Heartbeat

The heartbeat system tracks learning activity at 10-second intervals:

```json theme={null}
{
  "contentId": "lesson-001",
  "registrationId": "reg-123",
  "sessionId": "sess-456",
  "watchedSeconds": 120,
  "playbackRate": 1.0,
  "isPlaying": true,
  "isTabVisible": true,
  "isWindowFocused": true,
  "deviceFingerprint": "fp-hash-789"
}
```

**Processing pipeline:**

1. Client sends heartbeat batch (max 6 beats = 1 minute)
2. Server validates registration, product ownership, expiration
3. Updates `DailyLearningLedger` (per-actor daily tracking)
4. Enforces 8-hour daily cap (28,800 seconds)
5. Triggers EMON transmission on lesson completion

### Assessment System

Three assessment types with weighted scoring:

| Type           | Timing                                 | Weight | Features                                |
| -------------- | -------------------------------------- | ------ | --------------------------------------- |
| Progress Check | During course (configurable trigger %) | 20-30% | Must pass to unlock next lessons        |
| Final Exam     | After 80% progress                     | 50-60% | Time-limited, 3x question bank          |
| Assignment     | Anytime during course                  | 10-20% | Plagiarism detection (Jaccard + cosine) |

**Question bank:** Each exam draws from a 3x pool using Fisher-Yates shuffle. If an exam has 20 questions, at least 60 questions must exist in the bank.

**Auto-save:** Student answers are saved every 30 seconds to Redis (2-hour TTL), preventing data loss on connection drops.

***

## Anti-Fraud System (FDS)

### Protections

| Code | Protection                    | Method                                             |
| ---- | ----------------------------- | -------------------------------------------------- |
| C1   | CAPTCHA verification          | Math CAPTCHA, 2-hour Redis pass                    |
| C2   | Concurrent session prevention | Redis session lock                                 |
| C3   | Single learning window        | BroadcastChannel API                               |
| C4   | Inactivity auto-logout        | 2-hour idle timer                                  |
| C5   | Copy/paste prevention         | Exam mode clipboard blocking                       |
| C7   | Plagiarism detection          | Jaccard + 3-gram cosine similarity (80% threshold) |
| C8   | Assessment gate               | 80% progress required for final exam               |
| C10  | Minimum study time            | 50% of lesson duration required                    |
| C11  | IP-based fraud detection      | Behavioral analysis (partial)                      |

### Fraud Scoring (Workshop Attendance)

For workshop check-ins, a multi-layer fraud detection system runs in parallel:

```
Check-in Request
     │
     ├── Rate limit: 3 attempts / 5 min per session
     ├── Device duplicate: fingerprint across participants
     ├── GPS spoofing: geofence validation (accuracy > 50m = risk)
     └── Time anomaly: unrealistic check-in patterns
     │
     ▼
Fraud Score: 0.0 ─── 1.0
  │           │         │
  PASS      FLAG     BLOCK
 (<0.3)   (0.3-0.7)  (>0.7)
```

***

## EMON Integration

EMON (Electronic Monitoring) is the government's real-time monitoring system for HRD-Net courses.

### Data Transmission

The LMS transmits 6 record types to the EMON API:

| Table                     | Description     | Key Fields                            |
| ------------------------- | --------------- | ------------------------------------- |
| TB\_USER\_HIST\_V2        | Learner info    | Name, ID number, email, mobile        |
| TB\_USER\_LOGIN\_HIST\_V2 | Login history   | IP address, login timestamp           |
| TB\_COURSE\_HIST\_V2      | Course metadata | Total education hours, approval code  |
| TB\_CLASS\_HIST\_V2       | Class sessions  | Score, start/end date, insurance type |
| TB\_ATTEND\_HIST\_V2      | Attendance      | Progress rate (0-100), pass flag      |
| TB\_SCORE\_HIST\_V2       | Scores          | Eval type, score, IP, plagiarism flag |

### API Endpoints

```
POST /api/v1/learning/progress    → Lesson progress
POST /api/v1/assessment/result    → Assessment scores
POST /api/v1/completion           → Completion proof
```

The EMON adapter uses a queue system with exponential backoff retry:

```typescript theme={null}
EmonAdapter.forTenant(tenantId)
  .transmitProgress(learnerData)
  // Retry: 1s → 2s → 4s → 8s (max 4 attempts)
```

<Warning>
  EMON transmission failures are logged but do not block the learner experience. Failed transmissions are queued for retry. If retries are exhausted, an alert is generated for manual review.
</Warning>

***

## DPU Attendance Proof

Workshop attendance is sealed with DPU hash chains for tamper-evident proof.

### Flow

```
QR Scan → Check-in Request → Fraud Check → DPU Seal
                                              │
                                    ┌─────────┴─────────┐
                                    │  Local LMS Chain   │
                                    │  SHA-256 hash      │
                                    │  chainIndex: N     │
                                    └─────────┬─────────┘
                                              │
                                    ┌─────────▼─────────┐
                                    │   OPS DPU API      │
                                    │  /api/dpu/demo     │
                                    │  (non-blocking)    │
                                    └───────────────────┘
```

Each attendance record contains:

* `dpuChainHash`: SHA-256 hash linking to previous record
* `dpuChainIndex`: Sequential position in the chain
* `dpuId`: Reference to OPS DPU record

**Tamper detection:** Altering any single record breaks all downstream hashes in the chain, making tampering immediately detectable during audit.

### QR Check-in

```
POST /api/admin/attendance/{sessionId}/qr → Generate token (5-15 min TTL)

Learner scans QR → POST /api/attendance/check-in
{
  "token": "qr-token-abc",
  "gps": { "lat": 37.4845, "lng": 127.0340, "accuracy": 12.5 },
  "deviceFingerprint": "fp-hash-789"
}
```

***

## API Overview

### Learning APIs (v3)

| Method | Endpoint                          | Description               |
| ------ | --------------------------------- | ------------------------- |
| POST   | `/api/v3/learning/heartbeat`      | Submit activity heartbeat |
| GET    | `/api/v3/learning/hrd-status`     | Learner progress view     |
| POST   | `/api/v3/learning/hrd-assessment` | Submit exam/assignment    |
| GET    | `/api/v3/learning/hrd-completion` | Check completion status   |
| POST   | `/api/v3/learning/hrd-dashboard`  | Progress dashboard data   |

### Admin APIs (v2)

| Method   | Endpoint                      | Description              |
| -------- | ----------------------------- | ------------------------ |
| GET/POST | `/api/v2/admin/products`      | Course management        |
| GET/PUT  | `/api/v2/admin/emon-settings` | EMON configuration       |
| GET      | `/api/v2/admin/emon-logs`     | Monitoring logs          |
| GET      | `/api/v2/admin/hrd`           | HRD compliance dashboard |

### Attendance APIs

| Method | Endpoint                               | Description             |
| ------ | -------------------------------------- | ----------------------- |
| POST   | `/api/admin/attendance/sessions`       | Create workshop session |
| POST   | `/api/admin/attendance/{sessionId}/qr` | Generate QR token       |
| POST   | `/api/attendance/check-in`             | Learner check-in        |
| POST   | `/api/admin/attendance/manual`         | Manual check-in         |

### Payment APIs

| Method | Endpoint                | Description          |
| ------ | ----------------------- | -------------------- |
| POST   | `/api/payments/confirm` | Confirm Toss payment |
| POST   | `/api/payments/webhook` | Toss webhook handler |

***

## Product Types

| Type     | Use Case                    | Payment                  |
| -------- | --------------------------- | ------------------------ |
| COURSE   | HRD-Net remote training     | Via HRD-Net (government) |
| COACHING | 1:1 mentoring sessions      | Toss Payments            |
| PACKAGE  | Bundled courses             | Toss Payments            |
| WEBINAR  | Live online sessions (Zoom) | Toss Payments            |
| WORKSHOP | Offline group training      | Toss Payments            |

***

## Deployment

| Environment | URL                    | Branch    |
| ----------- | ---------------------- | --------- |
| Staging     | stg-learn.cronozen.com | `develop` |
| Production  | learn.cronozen.com     | `main`    |

Tenant subdomains: `{slug}.learn.cronozen.com`

### Database

* Separate PostgreSQL instance from OPS (independent RDS)
* Migration via Lambda: `./scripts/db-migrate.sh query lms-prod "SELECT ..."`
* DB aliases: `lms-stg`, `lms-prod`

### Tech Stack

| Layer      | Technology                                 |
| ---------- | ------------------------------------------ |
| Framework  | Next.js 16 + TypeScript                    |
| ORM        | Prisma 6.18                                |
| Database   | PostgreSQL (RDS, VPC internal)             |
| Cache      | Redis (sessions, heartbeat, draft answers) |
| Video      | Vimeo (HRD hosting)                        |
| Payment    | Toss Payments                              |
| Meeting    | Zoom API (webinars)                        |
| Monitoring | EMON API (government)                      |
| Auth       | OPS SSO (JWT)                              |
| Proof      | OPS DPU (SHA-256 chains)                   |