• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.936-938
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• 2018

본 논문은 IoT 환경에서 MQTT 대량 브로커와 대량 클라이언트간 효율적인 접속을 지원하기 위해 대량 접속처리 기능을 제공하는 CA(Connectionb Agent)를 포함한 MQTT 메시지 서버를 설계, 구현하였다. MTQQ 프로토콜은 MQTT 브로커와 MQTT 클라이언트로 구성되며, 각 MQTT 클라이언트는 MQTT 브로커의 중재를 받아 Pub/Sub 방식으로 메시지를 상호 전송한다. 이를 위해 MQTT 프로토콜은 MQTT 브로커와 MQTT 클라이언트 간 접속기능만을 제공한다. 실험결과에서 MQTT 메시지 서버는 초당 평균 12,500 건의 클라이언트 접속요청을 처리하였고, 20만건의 접속요청 처리에 16초가 소요되었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.900-903
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• 2016

A variety of measures in various fields, buildings, factories, offices, supermarkets, etc. through a sensor installed for energy savings and user convenience are transmitted and received by the cloud server. Also, this kind of sensor service increases considering the user's convenience. In this paper, we research a variety of meter data linkage between oracle database and time series database, and data analysis.

• Journal of information and communication convergence engineering
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• v.21 no.3
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• pp.185-191
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• 2023

The Internet of Things (IoT) can be defined as the connection of devices, sensors, and actors via the Internet to a single network to provide services to end-users. Owing to the flexibility and simplicity of IoT devices, which impart convenience to end-users, the demand for these devices has increased significantly in the last decade. To make these systems more scalable, achieve a larger number of connected devices, and achieve greater economic success, it is vital to develop them by considering parameters such as security, cost, bandwidth, data rate, and power consumption. This study aims to improve energy efficiency and prolong the lifetime of IoT networks by proposing a new approach called the constrained application protocol CoAP45. This approach reduces the number of updates to the CoAP server using a centralized resource. The simulation results show that the proposed approach outperforms all existing protocols.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.10
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• pp.311-322
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• 2014

IoT(Internet of Things) is a concept of connected internet pursuing direct access to devices or sensors in fused environment of personal, industrial and public area. In IoT environment, it is possible to access realtime data, and the data format and topology of devices are diverse. Also, there are bidirectional communications between users and devices to control actuators in IoT. In this point, IoT is different from the conventional internet in which data are produced by human desktops and gathered in server systems by way of one-sided simple internet communications. For the cloud or portal service of IoT, there should be a file management framework supporting systematic naming service and unified data access interface encompassing the variety of IoT things. This paper implements a DB-based virtual file system maintaining attributes of IoT things in a UNIX-styled file system view. Users who logged in the virtual shell are able to explore IoT things by navigating the virtual file system, and able to access IoT things directly via UNIX-styled file I O APIs. The implemented virtual file system is lightweight and flexible because it maintains only directory structure and descriptors for the distributed IoT things. The result of a test for the virtual shell primitives such as mkdir() or chdir() shows the smooth functionality of the virtual file system, Also, the exploring performance of the file system is better than that of Window file system in case of adopting a simple directory cache mechanism.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.1001-1006
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• 2023

Globally, rising energy costs and increased energy demand are important issues for the food processing and manufacturing industries, which consume significant amounts of energy throughout the supply chain. Accordingly, there is a need for the development of a real-time energy monitoring and analysis system that can optimize energy use. In this study, a food factory energy monitoring system was proposed based on IoT installed in a food factory, including monitoring of each facility, energy supply and usage monitoring for the heat treatment process, and search functions. The system is based on the IoT sensor of the food processing plant and consists of PLC, database server, OPC-UA server, UI server, API server, and CIMON's HMI. The proposed system builds big data for food factories and provides facility-specific monitoring through collection functions, as well as energy supply and usage monitoring and search service functions for the heat treatment process. This data collection-based energy monitoring system will serve as a guide for the development of a small and medium-sized factory energy monitoring and management system for energy savings. In the future, this system can be used to identify and analyze energy usage to create quantitative energy saving measures that optimize process work.

• IEMEK Journal of Embedded Systems and Applications
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• v.13 no.1
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• pp.25-32
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• 2018

In this paper, we present a proposed monitoring system for smart factories with several aspects, including information gathering, analysis, control, and display that relate to concurrently operation processes in the factory area. This paper proposes a monitoring and management system for industrial automation. In particular, it uses an Internet of Thing (IoT) device with a data protocol unit to convert the industrial protocols and transfer the information on various parameters. In the case of data communication, the proposed monitoring system is designed to support users to remotely manage with the cloud server by implementing conversion between Modbus RTU and Modbus TCP of protocol communications. The proposed communication technique has been verified by experiments.

• International Journal of Advanced Culture Technology
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• v.5 no.2
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• pp.90-97
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• 2017

The Internet of Things(IoT) market is expected to grow from 15.5billion to 75.4 billion by 2015-2025. As the number of IoT devices increases, the amount of data that is sent to the cloud is increasing. Today's Cloud Computing models are not suited to handle the vast amount of data generated by IoT devices. In this paper, we propose a Cooperation Coordinator System that reduces server load and improved real-time processing capability under specific circumstances by using Band-Cloud. The cooperation coordinator system dynamically forms the cloud when cooperation is needed between mobile devices located near. It is called Band-Cloud. Band-Cloud provides services entrusted by Central Cloud. This paper describes the proposed system and shows the cooperation process using the Android-based mobile devices and Wi-Fi Direct technology. Such a system can be applied to cases where real-time processing is required in a narrow area such as a hospital ward or a school classroom.

• Journal of Industrial Convergence
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• v.20 no.8
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• pp.61-67
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• 2022

The Internet of Things(IoT) is one of the key technologies in the Fourth Industrial Revolution. The IoT is a system that acquires information from various sensors and provides meaningful information to users. The method of obtaining information from sensor is using WIFI, Bluetooth and Server. is not accessible to external users because of different type of networks or local area communication. For this reason, there is a problem that external user cannot receive notification in regard to sensor information. In this paper, we want to establish a cloud message environment using Google's FCM(Firebase Cloud Messaging) and find out through experiments how users can receive notifications even if they are outside.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.485-487
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• 2017

With the growth of the IoT, security is a growing concern. Things the risk of IoT security has been constantly raised, and there have been many cases of hacking. As a result, there is a growing concern and scale about security, but there is a lack of interest and research on the message protocols between Iot devices. With the development of the IoT, the importance of low-power, lightweight and accurate message delivery will become more important and more advanced message protocols will be needed. In this paper, it is aimed to construct the system for communication between client and server of MQTT and CoAP with Confirmative option, which are most used among IoT message protocols and compare the message reliability of each communication protocol to check efficiency.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.5
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• pp.859-870
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• 2020

The MQTT-SN (Message Queuing Telemetry Transport-Sensor Network) protocol is a message transmission protocol used in a sensor-based Internet of Things (IoT) environment. This MQTT-SN protocol is a publish-subscribe model with a broker in the middle of message transmission, and each IoT device sends and receives messages through an intermediary when delivering messages. However, the MQTT-SN protocol does not provide security-related functions such as message security, mutual authentication, access control, and broker security. Accordingly, various security problems have recently occurred, and a situation in which security is required has emerged. In this paper, we review the security requirements of MQTT-SN once again, and propose a modified protocol that improves security while satisfying the constraints in the environment where the resource of IoT to which this protocol is applied is limited. Unlike the existing protocol, the security field and authentication server have been added to satisfy the security requirements. In addition, the proposed protocol is actually implemented and tested, and the proposed protocol is evaluated for practical use in terms of energy consumption.