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.tsDaily Limit Max 8 hours / 8 lessons per day lesson-unit-service.tsCompletion 80% progress + 60-point score hrd-completion-service.tsSequential Lessons must be completed in order Lesson unlock gates Assessment 3 types: progress check, final exam, assignment hrd-assessment-service.tsIdentity 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 recorddpuChainIndex: Sequential position in the chaindpuId: 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/heartbeatSubmit activity heartbeat GET /api/v3/learning/hrd-statusLearner progress view POST /api/v3/learning/hrd-assessmentSubmit exam/assignment GET /api/v3/learning/hrd-completionCheck completion status POST /api/v3/learning/hrd-dashboardProgress dashboard data
Admin APIs (v2) Method Endpoint Description GET/POST /api/v2/admin/productsCourse management GET/PUT /api/v2/admin/emon-settingsEMON configuration GET /api/v2/admin/emon-logsMonitoring logs GET /api/v2/admin/hrdHRD compliance dashboard
Attendance APIs Method Endpoint Description POST /api/admin/attendance/sessionsCreate workshop session POST /api/admin/attendance/{sessionId}/qrGenerate QR token POST /api/attendance/check-inLearner check-in POST /api/admin/attendance/manualManual check-in
Payment APIs Method Endpoint Description POST /api/payments/confirmConfirm Toss payment POST /api/payments/webhookToss 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 developProduction 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)
