From Factory Floor to Cloud

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1. 1번 문제

   Which industrial protocol is the vendor-neutral standard often used to read data from PLCs?

   • OPC UA
   • SNMP
   • SMTP
   • LDAP

2. 2번 문제

   In MQTT, what does a client connect to in order to publish and subscribe?

   • A topic server
   • A broker
   • A gateway hub
   • A message queue

3. 3번 문제

   A sensor reading must arrive exactly once, with no duplicates. Which MQTT QoS level guarantees this?

   • QoS 1 with retain
   • QoS 1
   • QoS 2
   • QoS 3

4. 4번 문제

   How does a device usually authenticate to AWS IoT Core over MQTT?

   • Username and password
   • Shared API key
   • IP allow-list
   • X.509 client certificate

5. 5번 문제

   Old PLCs speak Modbus only. Where is the data typically translated to MQTT?

   • Inside AWS IoT Core
   • On an edge gateway
   • In the MQTT broker
   • In the cloud database

6. 6번 문제

   Which AWS IoT Core feature routes incoming messages to services like S3, Lambda or Kinesis?

   • Rules engine
   • Device shadow
   • Fleet indexing
   • Job service

7. 7번 문제

   An app needs a machine's last reported state even while the machine is offline. What fits best?

   • A retained topic in S3
   • A Lambda cache layer
   • A Device Shadow
   • A Kinesis stream

8. 8번 문제

   The factory's internet link drops for an hour. What prevents data loss at the edge?

   • Higher MQTT QoS in the cloud
   • A larger cloud broker
   • Shorter keep-alive timers
   • Store-and-forward buffering

9. 9번 문제

   Why is a robot's emergency stop kept in the PLC rather than run from the cloud?

   • Cloud bills are too high
   • Latency must be deterministic
   • MQTT can't carry booleans
   • AWS forbids control use

10. 10번 문제

    In the ISA-95 model, which level holds the sensors and actuators themselves?

    • Level 0
    • Level 2
    • Level 3
    • Level 4