• Journal of Advanced Navigation Technology
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• v.18 no.1
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• pp.67-73
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• 2014

Due to the development of the communication technology and the high-performance mobile device, the number of video streaming service user has been increasing. Video streaming services in the restricted network environments need error control to support users for the Ultra High Definition(UHD) video delivery. Packet-level FEC method was used to control the error for delay-sensitive video service, but it has a defect in huge occupation of network resources by redundant packets. In this paper, we proposed a packet-level FEC algorithm which maintains the video quality by previous FEC methods and also reduces the occupation of network resource in the restricted network environments. The proposed algorithm controls the redundant rate with using the delivery characteristic of the video coding technology, and improves the efficiency of network resources by reducing the traffic by around 33% in comparison with the previous FEC methods.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.449-452
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• 2007

An intelligent robot with RSSI based indoor location estimation function was designed and implemented. A wireless sensor node was attached to the robot to received the location data from the indoor location estimation function. Spartan III was used as the main control device in the mobile robot. The current location data collected from the indoor location estimation system was transferred to the mobile robot and server through Zigbee/IEEE 802.15.4 wireless communication of the sensor node. Once the location data is received, the sensor node senses the direction of the robot head and directs the robot to move to its destination. Indoor location estimation intelligent robot is able to move efficiently and actively to the user appointed location by implementing the proposed obstacles avoidance algorithm. This system is able to monitor real-time environmental data and location of the robot using PC program. Indoor location estimation intelligent robot also can be controlled by executing the instructions sent from the PC program.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.405-406
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• 2012

A sensor network is composed of a large number of sensor nodes which have sensing, computation and wireless communication capabilities. The sensor node sends such collected data, usually via radio transmitter, to a command center (sink) either directly or through a data concentration center (a gateway). These sensor networks can be used for various application areas such as health, military, home network, managing inventory, monitoring disaster areas and so on. Moreover, owing to the rapid growth of mobile technology, high-performance smartphones are widespread and in increasing cases are utilized as a terminal device. In this paper, we propose a home management system using smartphone and sensor networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.758-767
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• 2017

IoT paradigm which makes a information without direct intervention of a human and interworks with other objects, humans and systems is attracting attention. It will be expected the number of smart devices equipped with sensors and wireless communication capabilities is reached to about 260 billion by 2020. With the vast amount of sending data generated from rapidly increasing number of smart devices, it will bring up the traffic growth over internet and congestion in wireless networks. In this paper, we utilize the smart device as a sink node to collect and forward the sensing data periodically in IoT and propose a heuristic algorithm for a selection of sink nodes' set with each sink node satisfies the QoS its applications because a selection of optimal sink nodes' set is NP-hard problem. The complexity of proposed heuristic algorithm is $O(m^3)$ and faster than the optimal algorithm.

• Journal of the Korea Society of Computer and Information
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• v.13 no.6
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• pp.203-210
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• 2008

Recently, as wireless communication are becoming more and more popular, Internet users is becoming increasingly demand HTTP-based web service in mobile computing environment. But, overall performance of web services may slow down, because mobile device are generally equipped with lower capability. Therefore, the most important factor to design wireless internet delivery system should be scalable to handle a large scale traffic due to rapidly growing users. But, in case of some preceding research, they not present a basic efficiency reform measure until currently. Therefore, In this paper, We propose a Web Service Delivery System for mobile environment that alleviates problems that occurred while executing web services in mobile environment and are helpful to overcome the above needs. The system composed of HTML/WML Converter, SOAP message processor. We compare the existing system with the proposed system.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.3 s.21
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• pp.89-97
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• 2002

We have developed the 45-Van system in order to maximize the interoperability of spatial data in 45(GNSS, SIIS, GIS, ITS) by sharing and providing spatial data of remote site. The 4S-Van system enables to acquisition and production of information for GIS database and the accurate position information by combining and connecting GPS/IMU, laser, CCD(charged-coupled device) image, and wireless telecommunication technology. That is, 4S-Van system measures its position and attitude using integrated GPS/IMU and takes two photographs of the front scene by two CCD cameras, analyzes position of objects by space intersection method, and constructs database that has compatibility with existing vector database system. Furthermore, infrared camera and wireless communication technique can be applied to the 4S-Van for a variety of applications. In this paper, we discuss the design and functions of 4S-Van that is equipped with GPS, CCD camera, and IMU.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.7
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• pp.1141-1148
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• 2017

Generally, a thermistor made by sintering a metal oxide is widely used to measure the ambient temperature. This thermistor is widely used not only for industrial use but also for medical use because of its excellent sensitivity, durability, temperature change characteristics and low cost. In particular, the normal body temperature is 36.9 degrees relative to the armpit temperature, and it is most closely related to the circulating blood flow. Previous studies have shown that body temperature changes during biomechanical changes and body temperature changes by anomalous signs or illnesses. Therefore, in this study, we propose a Lock-In-Amp design to detect minute temperature changes of clothing and thermistor wired by a preacher as a method to regularly measure body temperature in daily life. Especially, it is designed to measure the minute resistance change of the thermistor according to body temperature change even in a low-cost microprocessor environment by using a micro-processor-based Lock-In-Amp, and a jacquard and the thermistor is arranged so as to be close to the side, so that the reference body temperature can be easily measured. The temperature was measured and stored in real time using short-range wireless communication for non - restraint temperature monitoring. A baby vest was made to verify its performance through temperature experiments for infants. The measurement of infant body temperature through the existing skin sensor or thermometer has limitations in monitoring infant body temperature for a long time without restriction. However, it can be overcome by using the embroidery fabric based micro temperature monitoring wireless monitoring device proposed in this study.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.387-390
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• 2009

Digital devices that apply Ubiquitous-IT Convergence in ship manufacture are used as ship automation device. Need sailing data recording of ship black box that equip integrity and consecutiveness as legal confesser fare that inquire responsibility whereabouts of disaster such as fire of ship. It is research that create Forensic data from ship black box using Multidimensional networking that use ZigBee radio short distance communications division Wireless LAN with short distance RFID sensor that is used in ship in this treatise, UWB communication, GPS and artificial satellite. Sailing recording of shipping that is recorded to black box is transmited, and stores doubly by real time on ship insurance company and ship administration recording membrane using SHA-1 hash function and secure consecutiveness and integrity as Forensic data through artificial satellite encoding by 3DES 1024bit.

• Journal of the Korean Solar Energy Society
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• v.38 no.3
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• pp.21-28
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• 2018

The objects of PV (Photovoltaic) monitoring system is to reduce the loss of system and operation and maintenance costs. In case of PV plants with configured of centralized inverter type, only 1 PV module might be caused a large loss in the PV plant. For this reason, the monitoring technology of PV module-level that find out the location of the fault module and reduce the system losses is interested. In this paper, a fault diagnosis algorithm are proposed using thermal and electrical characteristics of PV modules under failure. In addition, the monitoring system applied with proposed algorithm was constructed. The wireless sensor using LoRa chip was designed to be able to connect with IoT device in the future. The characteristics of PV module by shading is not failure but it is treated as a temporary failure. In the monitoring system, it is possible to diagnose whether or not failure of bypass diode inside the junction box. The fault diagnosis algorithm are developed on considering a situation such as communication error of wireless sensor and empirical performance evaluation are currently conducting.

• Journal of the Korean Society of Systems Engineering
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• v.15 no.1
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• pp.34-42
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• 2019

Receiving great attention of IoT and 4th industrial revolution, the necessity comes to the fore of the plant system which aims making it smart and effective. Smart Factory is the key realm of IoT to apply with the concept to optimize the entire process and it presents a new and flexible production paradigm based on the collected data from numerous sensors installed in a plant. Especially, the wireless sensor network technology is receiving attention as the key technology of Smart Factory, researches to interface those technology is actively in progress. In addition, IoT devices for plant industry security and high reliable network protocols are under development to cope with high-risk plant facilities. In the meanwhile, Blockchain can support high security and reliability because of the hash and hash algorithm in its core structure and transaction as well as the shared ledger among all nodes and immutability of data. With the reason, this research presents Blockchain as a method to preserve security and reliability of the wireless communication technology. In regard to that, it establishes some of key concepts of the possibility on the blockchain based IoT Edge devices for Plant O&M (Operations and Maintenance), and fulfills performance verification with test devices to present key indicator data such as transaction elapsed time and CPU consumption rate.