• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.2
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• pp.111-117
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• 2020

The photovoltaic module has the characteristic that the output power varies according to the amount of insolation. If partial shading occurs in an environment composed of an array, a number of local maximum power points (LMPPs) may be generated according to the shading state. Photovoltaic arrays require global maximum power point tracking due to variations in output characteristics caused by solar radiation and temperature. Conventional algorithms, such as P&O and Incond, do not follow the global maximum power point in a partial shaded solar array. In this study, we propose a technique to follow the global maximum power point by using the correlation of voltage, current, and power in solar arrays. The proposed control technique 2qw validated through simulation and experiments by constructing a 2-kW solar system.

• Journal of Internet Computing and Services
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• v.20 no.2
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• pp.39-49
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• 2019

Advances in IoT data analysis technology have made it easier to analyze situation and provide interactive services based on the context. Most of digital signage application have been used to provide information uni-directionally, but in the future it will evolve to provide personalized content according to the individual user situation and responses. However, it is not easy to modify or apply the existing interactive digital signage platforms due to their hardware dependency. The proposed platform is modularized by dividing main functions into two, the cloud and the edge, so that advertisement resources can be easily generated and registered. Thus, interactive advertisement can be rendered in a timely manner based on sensor analysis results. At the edge, personal data can be processed to minimize privacy issues, and real-time IoT sensor data can be analyzed for quick response to the signage player. The cloud is easier to access and manage by multiple users than edge. Therefore, the signage content generation module improves accessibility and flexibility by handling advertisement contents in the cloud so that multiple users can work together on the cloud platform. The proposed platform was developed and simulated in two aspects. First is the provider who provides the signage service, and second is the viewer who uses the content of the signage. Simulation results show that the proposed platform enables providers to quickly construct interactive signage contents and responses appropriately to the context changes in real-time.

• Journal of Korea Society of Digital Industry and Information Management
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• v.18 no.4
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• pp.47-54
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• 2022

In this paper, MEMS embedded system design implemented the sensor events via analyzing the characteristics that dynamically happened to an abnormal status in power IoT environments in order to guarantee a maintainable operation. We used three kinds of tools in this paper, at first Bluetooth Low Energy (BLE) technology which is a suitable protocol that provides a low data rate, low power consumption, and low-cost sensor applications. Secondly LSM6DSOX, a system-in-module containing a 3-axis digital accelerometer and gyroscope with low-power features for optimal motion. Thirdly BM1422AGMV Digital Magnetometer IC, a 3-axis magnetic sensor with an I2C interface and a magnetic measurable range of ±120 uT, which incorporates magneto-impedance elements to detect the magnetic field when the current flowed in the power devices. The proposed MEMS system was developed based on an nRF5340 System on Chip (SoC), previously compared to the standalone embedded system without bluetooth technology via mobile App. And also, MEMS embedded system with BLE 5.0 technology broadcasted the MEMS system status to Android mobile server. The experiment results enhanced the performance of MEMS system design by combination of sensors, BLE technology and mobile application.

• Journal of the Korea Convergence Society
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• v.8 no.2
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• pp.15-20
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• 2017

In this paper, Esp8266, Node.js, and TCP / IP socket communication are used to design a compact data integration device. This device is designed to configure server and client using Esp8266 module that supports Wifi connection and to support bidirectional data transmission using TCP / IP socket communication. The server is configured using the Node.js operating system, and the database is integrated using Mysql. The network is designed to have a separate IP address by assigning a private IP address to the router, such as a home network. This device can transmit data bidirectionally, store individual client data on the server side, and can check the flow of data transmitted bidirectionally through wire-shark, so that it can be used as a compact real-time data integration and convergence device.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.1
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• pp.82-86
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• 2016

This paper proposes a method for the immobilization of motorbike brakes in conjunction with near-field communication (NFC) technology in order to meet the increasing demand for security and convenience of motorbike drivers. We thought about the concept of wireless key, NFC security devices and automatic solenoid valve for setting the lock and unlock module. This paper propose the design and development of an innovative anti-theft alarm system for motorcycles using NFC smart devices based on RFID system, the basis of IoT and AES(advanced encryption standard) encryption Algorithm. The design concept is based on NFC communication strategy between the vehicle and owner. To do this concept, we designed motorcycle smart key system with general-purpose NFC system and the automatic solenoid valve for setting the lock and unlock module. First, we designed control unit and NFC card reader for motorcycle smart key system. Then we propose an AES encryption algorithm and prove that the motorcycle key system is controllable by showing the result of implementing and testing, after installing.

• Journal of Internet of Things and Convergence
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• v.2 no.2
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• pp.21-26
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• 2016

In this paper, it is possible to update the tourist information in real time, on/off-line tour proposes a solution(BBTS) based on a bluetooth beacon can provide tourist information without the need for wireless data network. BBTS consists of a bluetooth based data of the low-power supply system and the beacons and interoperable smart applications. Data supply system consists of the BLE & Beacon Pairing-based / non-pairing data transmission module with integral hardware. Smart application modules that provide indoor location of users information, internal server module and tourist information collection and information guide around comprised of applications. The proposed BBTS is possible that indoor service tourism tourist demand due to utilizing the beacon technology. Outdoor tourist information is designed to be downloaded to the smartphone receives the information received from the beacon APK file to provide services. BBTS system is expected to make a big impact on the smart tourism services industry.

• Journal of Satellite, Information and Communications
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• v.10 no.1
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• pp.62-66
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• 2015

This paper introduces various applications and contents of digital signage, and analyzes conventional communication techniques to increase communication range. To realize digital signage in long distance, this paper proposes a hybrid modulation scheme and analyzes its performance. To verify its performance in real channel environment, we mapped symbols and experimented data transmission and reception with a visible light communication module with USRP. As a result, we confirmed a data receiving range and power of transmission and reception of the hybrid modulation mode. Also, we showed that the proposed modulation scheme has better performance of communication range and power efficiency than that of the conventional QAM technique.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1471-1478
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• 2016

In this study, the system to manage the power automatically was implemented by using Arduino, Raspberry pi, and Beacon technologies. Before the research, pre-research was carried out with the analysis on the existing power management systems in the market in order to find a solution to reduce burdens from standby power and power waste with the increase of electric charges. The system is designed to be able to deliver and receive data through IEEE 802.15.4 wireless protocol, by using Xbee module. Arduino was tested to verify whether it is able to control SSR(Solid State Relay), and it was found that there is no problem. Meanwhile, it was also tested whether it is possible to organize a star topology network through Arduino and Raspberry Pi, and it was confirmed that normal wireless communication is possible through IEEE 802.15.4 wireless protocol. It is designed that the signal from Android smartphone application is to be delivered to Raspberry Pi and then, to be delivered to Arduino through Xbee so that Arduino could control SSR. In addition to this, wireless protocol required to control Arduino with Raspberry Pi is also designed and applied to this research.

• Journal of Korea Society of Digital Industry and Information Management
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• v.17 no.4
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• pp.63-75
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• 2021

It is necessary to respond to rapid technological changes such as the 4th industrial revolution and digital transformation across industries. And, a change in the university education system is necessary in a crisis situation of universities due to the rapid decrease of the school-age population. This study is aimed at practical competency with the ability to apply intelligent information technology to their job fields based on a basic understanding of intelligent information technology rather than advanced competency centered on theory and research. Instead of presenting the curriculum system diagram so that it can be flexibly applied to the design and development of the curriculum for intelligent information technology, training modules according to job and level were presented. In relation to intelligent information technology, a questionnaire was conducted for college professors, and industry experts were conducted on the derived educational modules to reflect the opinions of the industry. Industry experts said that collaboration with PBL, Capstone, and industry is necessary to improve problem-solving and communication skills.

• Journal of Advanced Information Technology and Convergence
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• v.10 no.2
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• pp.49-59
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• 2020

As technologies have been developing, our lives are getting easier. Today we are surrounded by the new technologies such as AI and IoT. Moreover, the word, "smart" is a very broad one because we are trying to change our daily environment into smart one by using those technologies. For example, the traditional workplaces have changed into smart offices. Since the 3rd industrial revolution, we have used the touch interface to operate the machines. In the 4th industrial revolution, however, we are trying adding the speech recognition module to the machines to operate them by giving voice commands. Today many of the things are communicated with human by voice commands. Many of them are called AI things and they do tasks which users request and do tasks more than what users request. In the 4th industrial revolution, we use smartphones all the time every day from the morning to the night. For this reason, the privacy using phone is not guaranteed sometimes. For example, the caller's voice can be heard through the phone speaker when accepting a call. So, it is needed to protect privacy on smartphone and it should work automatically according to the user context. In this aspect, this paper proposes a method to adjust the voice volume for call to protect privacy on smartphone according to the user context.