This chapter defines the specifications, operation, and verification procedures for the temperature monitoring system, the IoT sensors, and the DAR (Data Acquisition and Recording) infrastructure that ensure specimen integrity during cryogenic transport. The standard requires the integrated operation of platinum resistance thermometers (PRTs), Type T, E, and K thermocouples capable of operating at -196°C, and wireless IoT gateways. In Korea, the infrastructure of the Korea Testing and Research Institute (KTR), the Korea Research Institute of Standards and Science (KRISS), and the Electronics and Telecommunications Research Institute (ETRI) provides the core resources for this domain.
Temperature sensors capable of operating in a cryogenic environment (-196°C) are classified into platinum resistance thermometers (PRTs), thermocouples, and semiconductor-based integrated-circuit (IC) sensors. This standard recommends the dual operation of a PRT and a Type T thermocouple, with mandatory calibration certification from KRISS.
The PRT is a sensor that exploits the proportionality of platinum resistance to temperature, providing the most accurate measurement in a cryogenic environment. Standard PRTs come in three types: Pt100 (100 Ω at 0°C), Pt500 (500 Ω at 0°C), and Pt1000 (1000 Ω at 0°C). This standard requires Class A or Class AA per IEC 60751:2008 (Industrial platinum resistance thermometers and platinum temperature sensors), adopted in Korea as KS C IEC 60751.
The accuracy of a PRT at -196°C is approximately ±0.43°C for Class A and ±0.21°C for Class AA. This standard sets Class A as the minimum requirement, ensuring the short-term deviation tolerance of ±2°C. The Korea Research Institute of Standards and Science (KRISS) serves as the calibration body for this standard, guaranteeing traceability to the International Temperature Scale of 1990 (ITS-90).
A thermocouple is a sensor that exploits the Seebeck effect at the junction of two dissimilar metals. This standard recommends three types: Type T (copper-constantan), Type E (chromel-constantan), and Type K (chromel-alumel) specialized for cryogenic use. Type T can measure down to -200°C and provides ±1.0°C accuracy in KTR calibration testing.
The advantage of thermocouples is a response speed approximately five times faster than a PRT (about 1 to 2 seconds versus 5 to 10 seconds); the disadvantage is lower absolute accuracy than a PRT. This standard combines the strengths of both sensors through dual operation of a PRT (accuracy) and a thermocouple (response speed).
Semiconductor IC sensors (e.g., Texas Instruments LM35, Maxim DS18B20) are inexpensive and provide digital output, but generally operate above -55°C and are therefore unsuitable for cryogenic measurement. This standard permits this category only as auxiliary sensors (e.g., for measuring external ambient temperature).
This standard applies a core temperature measurement interval of 15 seconds and a cloud transmission interval of 5 minutes by default. This section defines the specifications for measurement frequency, logging medium, and transmission protocol.
| Scenario | Measurement Interval | Logging Medium | Transmission Interval |
|---|---|---|---|
| Normal transport | 15 seconds | Local NAND flash plus cloud | 5 minutes |
| Transshipment | 5 seconds | Local plus real-time transmission | 1 minute |
| After deviation | 1 second | Local plus real-time transmission | 10 seconds |
| Emergency mode | 1 second | Local plus alarm transmission | Immediate |
| Post-arrival check | 1 second (for 10 minutes) | Local plus arrival report | Immediate |
Local data logging is performed on industrial NAND flash (MLC or SLC) or eMMC memory. This standard requires storage capacity for at least 30 days of data (approximately 256 MB), with redundant storage recommended to guard against data loss. The K-IoT standard library of the Electronics and Telecommunications Research Institute (ETRI) provides an open-source implementation that satisfies this specification.
Cloud transmission uses the MQTT or HTTPS protocol. This standard preferentially recommends MQTT 5.0 (2019, OASIS) and requires QoS Level 2 (Exactly Once Delivery). On transmission failure, data is queued locally and transmitted in batch after communication recovery. In Korea, Kakao Cloud, Naver Cloud Platform (NCP), and NHN Cloud are the major providers that support MQTT 5.0.
The DAR system is a core component of this standard. This section organizes the hardware architecture, firmware specifications, and certification status of Korean manufacturers.
A standard DAR system consists of the following five modules:
This standard requires DAR firmware to support the following eight functions: OTA (Over-The-Air) update with mandatory secure bootloader; encrypted storage using AES-256 or ChaCha20-Poly1305; clock synchronization via GPS or NTP; anomaly detection using Statistical Process Control (SPC); local alarm with buzzer, LED, and vibration motor; low-power mode with sleep outside measurement and transmission; self-diagnostic verification of sensor accuracy every 12 hours; and log integrity through SHA-256 hash chaining.
| Manufacturer | Model | Certification | Major Adoption |
|---|---|---|---|
| LG CNS | K-CRYO-DAR-100 | MFDS GMP, KTR | Seoul National University Hospital, Samsung Medical Center |
| SK Telecom | SKT-Bio-Track | KIAST, KOLAS | Asan Medical Center, Severance Hospital |
| KT | KT-MedChain DAR | MFDS GMP, KR | National Cancer Center, National Medical Center |
| ETRI | K-IoT Open Source | Open source (BSD-3) | KRIBB, KRICT, KIST |
| Q-RoCryo | K-VS-DAR | MFDS GMP | Major IVF clinics |
Calibration and traceability of temperature sensors are the foundation of the legal force of this standard. This section organizes the Korean calibration system and ITS-90 traceability.
ITS-90 is the international temperature scale adopted at the 1990 General Conference on Weights and Measures (CGPM). All temperature measurements in this standard must be traceable to ITS-90. In Korea, KRISS holds the national standard of ITS-90, and KOLAS-accredited testing laboratories guarantee traceability to KRISS.
This standard requires recalibration of all PRTs and thermocouples every 12 months. Calibration is performed at the following three standard points:
The calibration body is chosen among KRISS, KTR, and KOLAS-accredited testing laboratories. The calibration certificate is mandatory documentation for MFDS GMP post-market surveillance, and measurements with broken calibration traceability are subject to MFDS corrective orders.
This standard requires field verification before every transport departure. Verification is performed by two methods: liquid nitrogen verification, in which the sensor is immersed in a calibrated LN2 dewar for at least 5 minutes to confirm the -196°C reading (tolerance ±0.5°C); and dry ice verification, in which the sensor is immersed in a calibrated dry ice and alcohol slurry (-78.5°C) for 5 minutes (tolerance ±1.0°C).
This section defines the communication infrastructure between the DAR system and the cloud backend. In Korea, the LTE-M (Cat-M1) and NB-IoT networks of SK Telecom, KT, and LG U+ constitute the standard infrastructure.
LTE-M is a low-power, medium-speed (up to 1 Mbps) IoT network, with nationwide service from SK Telecom, KT, and LG U+. It is optimized for the 5-minute transmission interval of this standard, and module cost is approximately one-third that of a typical LTE modem. The K-IoT standard library of ETRI provides a standard API for LTE-M.
NB-IoT is an ultra-low-power, low-speed (up to 250 kbps) IoT network used for emergency alarm message transmission in this standard. The NB-IoT networks of SK Telecom, KT, and LG U+ operate even in environments where typical LTE signals are weak, such as underground parking lots, tunnels, and at sea.
Wi-Fi (2.4 GHz, 5 GHz) and BLE (Bluetooth Low Energy) are used for data synchronization at the origin facility, transshipment points, and destination facility. The Cool Cargo Center at the Incheon Airport cargo terminal of Korea Airports Corporation (KAC) and the Hanjin Logistics hubs all operate dedicated IoT Wi-Fi networks and use BLE beacons for auxiliary location tracking.
This standard recommends LTE-M (primary) plus NB-IoT (secondary) or LTE-M (primary) plus Wi-Fi (secondary) redundancy. If the primary communication is disconnected for more than 15 minutes, automatic failover to the secondary occurs. If both are disconnected, data is accumulated in the local queue and transmitted in batch after communication recovery.
This section defines Statistical Process Control (SPC) for DAR data and anomaly detection algorithms.
This standard recommends the use of four SPC charts: an X-bar chart tracking the mean temperature over a time window (e.g., 1 hour); an R chart tracking the temperature range over a time window; a CUSUM chart tracking cumulative deviation, excellent for detecting small shifts; and an EWMA chart, an exponentially weighted moving average, excellent for trend detection.
This standard adopts the four Western Electric Rules:
If any of the above rules is violated, the system raises an automatic alarm, switches the measurement interval to 1 second, and notifies the operator by SMS, email, and mobile app push. In Korea, for MFDS GMP-certified facilities the alarm data is automatically reported to the MFDS e-cris system within 24 hours.
In 2024, MFDS GMP-certified facilities in Korea reported a total of 487 DAR alarms, of which 372 (76.4%) were transient deviations during transshipment, 89 (18.3%) were transient deviations during LN2 replenishment, and 26 (5.3%) were actual events that affected specimen integrity. All such events were handled in accordance with the standard emergency procedures of Hanjin Logistics, CJ Logistics, and Lotte Global Logistics.
This section analyzes five representative cases in which the DAR system was actually applied in Korea.
In the first quarter of 2024, the IVF clinic of Seoul National University Hospital introduced 24 units of LG CNS K-CRYO-DAR-100. This case is recorded as the first in Korea to simultaneously satisfy MFDS GMP certification and KOLAS calibration certification by KTR. Over 12 months of operation, measurement reliability was 99.998% (average of 0.5 deviations per month), with a mean calibration deviation of ±0.18°C.
Samsung Medical Center adopted 16 units of SKT-Bio-Track in the second quarter of 2024. The system uses SK Telecom's LTE-M network as the primary channel and is integrated with Kakao Cloud's IoT platform. In 187 international air transports over one year after adoption, zero communication interruption events were recorded.
The National Cancer Center adopted 8 units of KT-MedChain DAR in the third quarter of 2024. This system is a representative case of integration between KT's NB-IoT network and a blockchain-based chain of custody, detailed in Chapter 8 of this book.
The KRIBB National Biological Resources Bank built its own DAR system using ETRI's K-IoT open-source library. The system is published under the BSD-3 license and is shared by five national research institutions, including KRIBB, KRICT, KIST, KFRI, and KAIST.
The K-VS-DAR system of Q-RoCryo, a KRICT spin-off, was adopted by 47 IVF clinics nationwide in 2024. The system is designed as an integrated dry shipper, fundamentally solving the data synchronization issues associated with separate operation of the container and the DAR.
The Cool Cargo Center at the Incheon Airport cargo terminal, jointly operated by Incheon International Airport Corporation and the Korea Airports Corporation (KAC), introduced an integrated DAR infrastructure in the fourth quarter of 2024. This infrastructure is shared by seven carriers — FedEx Korea, DHL Korea, UPS Korea, Hanjin Logistics, CJ Logistics, Lotte Global Logistics, and Korea Post — enabling automatic data synchronization during transshipment. After adoption, the mean data synchronization time at transshipment shortened from 3.2 minutes to 0.4 minutes.
In 2024, the KAIST Graduate School of Medical Science and Engineering launched a joint research program with KRICT, KIST, and ETRI to develop next-generation cryogenic IoT sensors. The goal is to develop a single-chip sensor that integrates a PRT and a thermocouple, with a prototype targeted for release in 2026. The research has been selected as a K-Bio national strategy project of the Ministry of Science and ICT and is supported by approximately 32 billion KRW over five years.
In 2024 the Ministry of Food and Drug Safety (MFDS) added an automatic DAR data ingestion function to its e-cris system. This function greatly reduces the post-market surveillance reporting burden of Korean GMP-certified facilities and can process an average of 1,200 DAR messages per hour. With the introduction of this function, mean MFDS post-market surveillance reporting time shortened from 24 hours to 0.5 hours. The Korea Non-Life Insurance Association evaluated this function and decided on an additional 5% premium discount for GMP-certified facilities.
The simulator of this standard supports learning, verification, and certification of the DAR system.
In the simulator's data-format panel, the user enters patient identifier (patientId), origin facility (originFacility), destination facility (destFacility), target temperature (targetTemp), and current temperature (currentTemp) to generate the standard message of the DAR system. Korean users can select origin and destination facilities from Seoul National University Hospital, Samsung Medical Center, Asan Medical Center, Severance Hospital, the National Cancer Center, the National Medical Center, KRIBB, the KAIST Graduate School of Medical Science and Engineering, and the KIST Brain Science Institute.
The algorithms panel simulates the automatic execution of SPC charts and Western Electric Rules. Korean users can learn the automatic detection workflow of various anomaly scenarios — transient deviations during transshipment, transient deviations during LN2 replenishment, and critical deviations during facility failure — in this panel.
The protocol panel visualizes the message flow of MQTT 5.0 QoS Level 2. Korean users can simulate integration with the LTE-M networks of SK Telecom, KT, and LG U+ in this panel.
The integration panel simulates OAuth 2.0 integration with the MFDS e-cris system. Korean users can learn the MFDS automatic reporting workflow in this panel.
The test panel performs integrated verification of the full DAR operation scenario (pre-departure check, in-transit, transshipment, post-arrival check). The simulator's phase1 through phase5 outputs map directly to the four-stage operational procedure of this chapter.
This section defines the legal force, retention periods, and litigation use of DAR data.
This standard defines DAR data retention periods as follows: transport data (original) — permanent retention (at least 30 years) under Article 8 of the Human Tissue Safety and Management Act; log integrity verification data — permanent retention per the MFDS GTP notification; emergency alarm data — permanent retention as accident record obligation; and routine operation data — 10-year retention per the Medical Service Act enforcement regulation.
The legal force of DAR data is guaranteed when all of the following requirements are satisfied: KRISS-traceable calibration certification; SHA-256 hash chain integrity; automatic reporting to the MFDS e-cris system; consistency with KR or KIAST container certification; and consistency with Korea Customs Service import notification data.
In 2024, DAR data was used in seven litigation cases in Korea, all involving damages claims for specimen loss or integrity compromise. Six cases ended in favor of the plaintiff (specimen owner) and one in favor of the defendant (carrier). DAR data integrity was recognized in every case. These cases are anonymized and recorded in the 2024 report of the Korea Non-Life Insurance Association.
This section analyzes Korea's IoT communication infrastructure from the perspective of operating the DAR system of this standard.
SK Telecom is the market leader in Korean IoT and operates an LTE-M (Cat-M1) network nationwide. SKT's LTE-M provides signal quality of 99.7% or higher at major airports including Incheon International Airport, Gimpo Airport, Gimhae Airport, and Jeju Airport, and at the major ports of Busan, Incheon, and Gwangyang. With the 5-minute transmission interval recommended by this standard, the mean message delay is 1.8 seconds. SKT operates its proprietary IoT platform ThingPlug, which fully supports MQTT 5.0 QoS Level 2.
KT excels in NB-IoT and provides strong signal coverage even in environments where typical LTE signals are weak, such as underground parking lots, tunnels, and at sea. KT IoT Makers, KT's IoT platform, provides domain-specific functions for medical and bio applications and guarantees data governance that satisfies MFDS GMP certification requirements. The mean delay of an NB-IoT emergency alarm message in this standard is 0.9 seconds.
LG U+ excels in industrial IoT and provides medical IoT solutions in collaboration with LG CNS. The LG CNS K-CRYO-DAR-100 system, frequently cited in this book, is integrated by design with LG U+'s LTE-M network. The LG U+ IoT cloud platform is compatible with Kakao Cloud and is one of the most common operating combinations in Korea.
Carrier selection for the DAR system of this standard follows these criteria: SK Telecom LTE-M for domestic inter-city transport (highest national signal quality); KT NB-IoT for underground, tunnel, and maritime transport (strength in low-signal environments); LG U+ with LG CNS integration for in-facility medical operation; and SK Telecom with global roaming for international air transport (automatic switching to destination carriers).
Security and privacy of the DAR system are directly linked to the protection of patient rights. This section organizes compliance with the Korean Personal Information Protection Act and MFDS medical device cybersecurity guidelines.
This standard requires encryption in three domains. Data at rest: AES-256-GCM or ChaCha20-Poly1305. Data in transit: TLS 1.3 or above, MQTT over TLS. Data in use: homomorphic encryption or Trusted Execution Environment (TEE) recommended. In Korea, the use of modules certified by the National Intelligence Service's KCMVP (Korea Cryptographic Module Validation Program) is recommended.
The patient identifier is a core metadata element of this standard but is operated separately from the patient's direct identity. This standard requires that the patient identifier not be mapped to personal information such as resident registration number, name, or address; the mapping table is kept in a separate security system at the MFDS GMP-certified facility. Article 29 of the Personal Information Protection Act and the confidentiality obligation of Article 21 of the Medical Service Act apply concurrently.
The DAR system of this standard must satisfy the requirements of the MFDS Medical Device Cybersecurity Guideline 2024. Major requirements include a secure bootloader, digital signature of OTA updates, intrusion detection and logging, and rapid vulnerability response procedures. Compatibility with the K-Shield certification of the Korea Internet and Security Agency (KISA) and conformity with the FDA Premarket Cybersecurity Guidance for global market entry are also required.
This chapter has defined the specifications, operation, and verification procedures of the temperature monitoring system, IoT sensors, and DAR system during cryogenic transport. The dual operation of PRTs and thermocouples, ITS-90-based calibration, 15-second measurement and 5-minute cloud transmission intervals, MQTT 5.0 QoS Level 2 protocol, and SPC charts with Western Electric Rules-based anomaly detection are the core specifications of this chapter.
In Korea, LG CNS, SK Telecom, KT, ETRI, and Q-RoCryo are the five major suppliers of DAR systems, and KRISS, KTR, and KOLAS-accredited testing laboratories guarantee calibration traceability. The LTE-M and NB-IoT networks of SK Telecom, KT, and LG U+ are the communication infrastructure of this standard, and Kakao Cloud, Naver Cloud Platform, and NHN Cloud provide MQTT 5.0 cloud services. Automatic integration with the MFDS e-cris system, and the hub infrastructure of the Korea Airports Corporation (KAC), Incheon International Airport, Hanjin Logistics, CJ Logistics, and Lotte Global Logistics, form the basis on which the standard of this chapter actually operates in the Korean environment. The data collection specifications of this chapter are integrated with the GPS tracking of the subsequent Chapter 4 (transport route).