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

Remote Training LMS

HRD-Net compliant online courses for government-subsidized programs (내일채움카드). Includes EMON integration, anti-fraud protections, and automated compliance reporting.

Workshop Management

Offline seminar and workshop management with QR check-in, DPU attendance proof, capacity management, and location tracking.

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:

{
  "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:

{
  "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:

Client sends heartbeat batch (max 6 beats = 1 minute)
Server validates registration, product ownership, expiration
Updates DailyLearningLedger (per-actor daily tracking)
Enforces 8-hour daily cap (28,800 seconds)
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:

EmonAdapter.forTenant(tenantId)
  .transmitProgress(learnerData)
  // Retry: 1s → 2s → 4s → 8s (max 4 attempts)

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.

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)

​LMS Platform

​Product Lineup

Remote Training LMS

Workshop Management

​Architecture

​Hub-Spoke Integration

​Multi-Tenant Structure

​Tenant Configuration

​HRD-Net Compliance

​Regulatory Requirements

​Core Rules

​Learning Heartbeat

​Assessment System

​Anti-Fraud System (FDS)

​Protections

​Fraud Scoring (Workshop Attendance)

​EMON Integration

​Data Transmission

​API Endpoints

​DPU Attendance Proof

​Flow

​QR Check-in

​API Overview

​Learning APIs (v3)

​Admin APIs (v2)

​Attendance APIs

​Payment APIs

​Product Types

​Deployment

​Database

​Tech Stack

LMS Platform

Product Lineup

Architecture

Hub-Spoke Integration

Multi-Tenant Structure

Tenant Configuration

HRD-Net Compliance

Regulatory Requirements

Core Rules

Learning Heartbeat

Assessment System

Anti-Fraud System (FDS)

Protections

Fraud Scoring (Workshop Attendance)

EMON Integration

Data Transmission

API Endpoints

DPU Attendance Proof

Flow

QR Check-in

API Overview

Learning APIs (v3)

Admin APIs (v2)

Attendance APIs

Payment APIs

Product Types

Deployment

Database

Tech Stack