• International Journal of Computer Science & Network Security
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• v.21 no.11
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• pp.301-311
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• 2021

The technological advancements of the last two decades directed the era of the Internet of Things (IoT). IoT enables billions of devices to connect through the internet and share their information and resources on a global level. These devices can be anything, from smartphones to embedded sensors. The main purpose of IoT is to make devices capable of achieving the desired goal with minimal to no human intervention. Although it hascome as a social and economic blessing, it still brought forward many security risks. This paper focuses on providing a survey of the most commonly used application layer protocols in the IoT domain, namely, Constrained Application Protocol (CoAP), Message Queuing Telemetry Transport (MQTT), Advanced Message Queuing Protocol (AMQP), and Extensible Messaging and Presence Protocol (XMPP). MQTT, AMQP, and XMPP use TCP for device-to-device communication, while CoAP utilizes UDP to achieve this purpose. MQTT and AMQP are based on a publish/subscribe model, CoAP uses the request/reply model for its structuring. In addition to this, the quality of service provision of MQTT, AMQP, and CoAP is not very high, especially when the deliverance of messages is concerned. The selection of protocols for each application is very a tedious task.This survey discusses the architectures, advantages, disadvantages, and applications of each of these protocols. The main contribution of this work is to describe each of the aforementioned application protocols in detail as well as providing their thorough comparative analysis. This survey will be helpful to the developers in selecting the protocol ideal for their system and/or application.

• Journal of Internet of Things and Convergence
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• v.10 no.2
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• pp.131-135
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• 2024

In the MQTT protocol, if the retained flag of a message published by a publisher is set, the message is stored in the broker as a retained message. When a new subscriber performs a subscribe, the broker immediately sends the retained message. This allows the new subscriber to perform updates on the current state via the retained message without waiting for new messages from the publisher. However, sending retained messages can become a traffic overhead if new messages are frequently published by the publisher. This situation could be considered an overhead when new subscribers frequently subscribe. Therefore, in this paper, we propose a retained message delivery scheme by considering the characteristics of the published messages. We model the delivery and waiting actions to new subscribers from the perspective of the broker using reinforcement learning, and determine the optimal policy through Q learning algorithm. Through performance analysis, we confirm that the proposed method shows improved performance compared to existing methods.

• Smart Media Journal
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• v.13 no.4
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• pp.76-85
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• 2024

In this paper, we propose a system that improves the data integrity of IoT(Internet of Things) devices in the virtual environment by combining Hyperledger Indy and MQTT(Message Queuing Telemetry Transport). The system complements the limitations of the centralized system by realizing a DPKI(Decentralized Public Key Infrastructure) structure that utilizes a distributed network in publish-subscribe(pub/sub) pattern communication. Digital signature technology was applied to ensure the data integrity of IoT devices and communication scenarios between the four core components of the client, IoT device, broker, and blockchain, as well as a topic structure using a decentralized identifier to ensure safety in the virtual environment. We present a systematic method for transparent data exchange. To prove the performance of the proposed system, this paper conducted experiments on four scenarios and evaluated communication performance in a virtual environment. The experimental results confirmed that the proposed system provides a reliable IoT data communication structure in a virtual environment.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.297-299
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• 2016

기술의 발달과 융합으로 사물인터넷(Internet of Things; IoT)의 시대가 열렸다. 빅 데이터와 센서의 발달로 인해 정보는 전과 달리 더욱 사용자와 밀접해졌고 다양해졌으며 양 또한 많아졌다. 이와 더불어 IoT 환경은 다양한 기술들이 융합된 구조로 기존 기술들이 가지고 있는 보안 취약점뿐만 아니라 보다 복잡한 보안 문제점들이 발생할 수 있다. 본 논문에서는 IoT 환경에서 서비스나 IoT 기기들이 갖춰야할 보안 요구사항들을 확장성(scalability), 상호운용성(interoperability), 최소 자원 필요성(minimum resource necessity)으로 분류 하고 정의하였으며, IoT 서비스를 제공하기 위해 사용하는 대표적 프로토콜인 MQTT(Message Queue Telemetry Transfer)와 CoAP(Constrained Application Protocol)에 초점을 맞춰 각각의 표준 문서에서 권고하고 있는 보안 기술에 대해 살펴본다. 또한 그런 기술들에 있어서 발생 가능한 보안 취약점들을 분석하고 이를 해결하기 위한 방법을 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.73-76
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• 2014

현재 네트워크 시스템은 유선에서 무선으로 발전하면서 많은 업무가 모바일 기반의 업무로 변화되고 있다. 그 중 대표적인 것이 모바일 오피스 시스템으로 중요 구성요소 중 하나인 커뮤니케이션은 구성원간의 단문 메시지 서비스(SMS)이다. 그러나 최근 무선 환경의 발전으로 단문 메시지 전송 방식이 SMS에서 모바일 메신저로 변화하고 있으나 그에 대처하지 못한 시스템들이 있다. 이에 본 논문에서는 모바일 오피스 시스템에서 사용되고 있는 SMS를 대체하여 MQTT(Message Queuing Telemetry Transport) 프로토콜을 이용한 협업 메신저 시스템을 설계 및 구현한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2024.01a
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• pp.145-146
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• 2024

본 논문에서는 최근 몇 년 동안 스마트시티 인프라 투자가 크게 성장하였으며 글로벌 스마트 쓰레기통 시장은 성장 가능성이 높을 것으로 예상된다. 본 논문에서는 이에 발맞추어 CNN과 MQTT를 활용한 스마트 쓰레기통을 제작하였다. 쓰레기의 종류를 구별하고 해당되는 쓰레기통의 뚜껑을 골라 여는 것은 현대인의 생활에서 비효율을 야기한다. 이러한 문제를 해결하고자 CNN을 통한 효율적인 분류와 MQTT를 통한 통신, 센서들을 활용한 더 나은 쓰레기 수거 방식을 제공한다. 스마트 쓰레기통으로 일상을 더욱 편하고 효율적이게 만드는 데 기여하고자 한다.

• Review of KIISC
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• v.24 no.6
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• pp.37-47
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• 2014

최근 정보통신기술 분야의 최대 관심사는 모든 사물간의 통신이 이루어지는 Internet Of Things, 더 나아가 Internet Of Everythings 분야이다. 이러한 흐름에 발맞추어 사물과 관련된 다양한 기술이 점진적으로 발달하였고, 누구나 쉽게 사물간의 인터넷 결합을 이용하여 Ubiquitous 시대를 맞이해 인간의 편리성을 위한 다양한 서비스를 이용할 수 있을 것으로 예상된다. 앞으로의 우리 생활에 점차 밀접한 관계를 맺음에 따라 다양한 기술들이 개발 및 접목될 것으로 예상이 된다. 본 논문에서는 Internet Of Things의 시대가 발전함에 따라 이에 관련된 현재 활용되는 기술 중 MQTT(Message Queue Telemetry Transport)에 대해 기술 할 것이며 이 기술과 관련된 다양한 정보 침해에 대한 향후대책 및 대응방안에 대해 기술한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.231-237
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• 2017

This paper presents an implementation of a smart flowerpot which can adjust humidity and illumination automatically after monitoring the temperature, humidity, and illumination. We made a container of the flowerpot with a 3D printer and embedded a NodeMCU micro controller in it. We attached a temperature sensor, a humidity sensor, an illumination sensor, and a water pump to the NodeMCU. We developed a control program that adjusts humidity and illumination and ran it on the NodeMCU. Also we developed an Android application and set up an MQTT server. Using the MQTT server, the NodeMCU and the Android application can exchange messages which keep sensor values and commands. Using the Android application. the user can send the proper temperature, humidity, and illumination to the smart flowerpot and monitor the sensor values.

• Convergence Security Journal
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• v.22 no.4
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• pp.17-24
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• 2022

Recently, machine learning-based cyber attack detection and classification research has been actively conducted, achieving a high level of detection accuracy. However, low-spec IoT devices and large-scale network traffic make it difficult to apply machine learning-based detection models in IoT environment. Therefore, In this paper, we propose an efficient IoT attack detection and classification method through PCA(Principal Component Analysis) and LightGBM(Light Gradient Boosting Model) using datasets collected in a MQTT(Message Queuing Telementry Transport) IoT protocol environment that is also used in the defense field. As a result of the experiment, even though the original dataset was reduced to about 15%, the performance was almost similar to that of the original. It also showed the best performance in comparative evaluation with the four dimensional reduction techniques selected in this paper.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.586-589
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• 2017

The vibration monitoring system using the sensor network is used in various fields. However, in case of the vibration of the existing products, the size of the monitoring system is increased due to the separation of the sensor data collection function and the communication function. In this paper, we design and implement a lightweight vibration monitoring system using the MQTT protocol, which is oneM2M device standard protocol for the Arduino and Ethernet modules, to monitor frequent earthquakes and vibrations in narrow places.