• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.5
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• pp.418-426
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• 2019

Recently, many studies on vital sign detection using a radar sensor related to Internet of Things(IoT) smart home systems have been conducted. Because vital signs such as respiration and cardiac rates generally cause micro-motions in the chest or back, the phase of the received echo signal from a target fluctuates according to the micro-motion. Therefore, vital signs are usually detected via spectral analysis of the phase. However, the probability of false alarms in cardiac rate detection increases as a result of various problems in the measurement environment, such as very weak phase fluctuations caused by the cardiac rate. Therefore, this study analyzes the difficulties of vital sign detection and proposes an efficient vital sign detection algorithm consisting of four main stages: 1) phase decomposition, 2) phase differentiation and filtering, 3) vital sign detection, and 4) reduction of the probability of false alarm. Experimental results using impulse-radio ultra-wideband radar show that the proposed algorithm is very efficient in terms of computation and accuracy.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.642-648
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• 2019

Vessels sail according to the COLREG to prevent a collision. However, it is difficult to apply COLREG under special situation as heavy traffic, at this time personal skills of the operator are required. In this case, traffic control is required through the maritime traffic monitoring system. Therefore, maritime traffic management is globally implemented by VTS. In this system, VTS of icer uses the VTS system to assess risks and recommends possible safety operation to vessels with radio systems. This study considers that the risk analysis method with AI (Artificial Intelligence) technology from the operator's aspect. In addition, the research explains the Maritime Traffic Safety Monitoring System, Including AR (Augmented Reality) technology to increase vessel control efficiency. This system is able to predict hazards and risk priorities, and it leads to sequential elimination of dangerous situations. Especially, the hazard situations can be analyzed from operator's perspective of each vessel instead of the VTS officer's aspect, which is more practical than the conventional method. Furthermore, the result of analysis enables to comprehend quantitative hazardous areas and support recommended routes to avoid a collision. As a result, I firmly believe that the system will support to prevent a collision in complex traffic waters. In particular, it could be adopted as a collision prevention system for Maritime Autonomous Surface Ship, which occupies a significant proportion in Maritime 4th industrial revolution.

• Science of Emotion and Sensibility
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• v.15 no.1
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• pp.65-72
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• 2012

People receive information through various media, such as newspapers, TV, radio, magazines, or internet, etc. In particular, through the development of the internet and smart-phone they can interact with media and receive information in real time via handheld devices. However the types of information and media could affect the reliability of news information. In this study, it was the main interest how the usability in the new media with the interactivity, such as a desktop, tablet, and smart-phone affects the user's evaluation on the contents displayed by the different new media. Therefore, the present study was conducted to investigate the effect of the usability from the different display size of media and the different contents of articles on the reliability of information empirically. The results showed that the contents of the articles interacting with different devices affect the reliability of information. These findings propose the considerations on the effects of characteristic usability of the new media in the stages of the development of the media contents.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.5
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• pp.1122-1127
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• 2014

WLAN is affordability, flexibility, and ease of installation, use the smart device due to the dissemination and the AP (Access Point) to the simplification of the Office building, store, at school. Wi-Fi radio waves because it uses the medium of air transport to reach areas where security threats are always exposed to illegal AP installation, policy violations AP, packet monitoring, AP illegal access, external and service access, wireless network sharing, MAC address, such as a new security threat to steal. In this paper, signature-based of wireless intrusion detection system for Snort to suggest how to develop. The public can use hacking tools and conduct a mock hacking, Snort detects an attack of hacking tools to verify from experimental verification of the suitability of the thesis throughout.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.834-841
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• 2012

In order to the mobile service uses the wireless terminal including the development of the wire wireless network and Smart phone, and etc. use including mobile office, which and etc. increases. Because in order that the u-Healthcare service using this appeared before the footlights and the existing quality measurement reference considered the speed, error rate, and etc. just, guarantees the stability of the u-Healthcare, the quality control by service are necessary. In this paper, the quality measurement reference by mobile service considering the radio environment as the method for satisfying the quality guarantee of the u-Healthcare mobile service user and user needs was presented. The WiBro u-Healthcare wireless data service quality based system in the end user perspective was established through the main performance index and entrepreneur case presented in the international standardization institute including 3GPP, WiMAX forum, GSMA, and etc. through the related research and the validity of the quality index establishment was presented according to each service.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.1
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• pp.47-53
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• 2011

To enable the efficient operation of ITS, it is necessary to collect location data for vehicles on the road. In the case of futuristic transportation systems like ubiquitous transportation and smart highway, a method of data collection that is advanced enough to incorporate road lane recognition is required. To meet this requirement, technology based on radio frequency identification (RFID) has been researched. However, RFID may fail to yield accurate location information during high-speed driving because of the time required for communication between the tag and the reader. Moreover, installing tags across all roads necessarily incurs an enormous cost. One cost-saving alternative currently being researched is to utilize GNSS (global navigation satellite system) carrierbased location information where available. For lane recognition using GNSS, a precise digital map for determining vehicle position by lane is needed in addition to the carrier-based GNSS location data. A "precise digital map" is a map containing the location information of each road lane to enable lane recognition. At present, precise digital maps are being created for lane recognition experiments by measuring the lanes in the test area. However, such work is being carried out through comparison with vehicle driving information, without definitions being established for detailed performance specifications. Therefore, this study analyzes the performance requirements of a precise digital map capable of lane recognition based on the accuracy of GNSS location information and the accuracy of the precise digital map. To analyze the performance of the precise digital map, simulations are carried out. The results show that to have high performance of this system, we need under 0.5m accuracy of the precise digital map.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.49 no.3
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• pp.46-55
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• 2012

Recently, the concept of PES(Personal Environment Service) is being widely discussed on various standardization organizations such as ITU-R, ETSI, 3GPP, TTA and etc. The purpose of PES is to introduce the services which can dynamically, automatically and intelligently reconfigures the electronic, electrical, and mechanical equipment surrounding the user according to the user preferences included in a user's profile by using a smartphone embedding WPAN radio technologies such as bluetooth and WiFi. This research introduces an Android Platform-based PES system which consists of a PES app, PES devices and a PES server. A smartphone platform is Android 2.2(Froyo) version and 4 simulated PES devices were implemented by using Galaxy Tab. It has shown that the PES would be a killer application of M2M(Machine-to-Machine) or D2D(Device-to-Device) in the future and it would need to study how to update a user's profile based on analyzing user's behaviour for enhancing the PES user's satisfaction.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.4
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• pp.871-883
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• 2016

It has been steadily increasing to use a wireless keyboard via Radio Frequency which is the input device. Especially, wireless keyboards that use 2.4 GHz frequency band are the most common items and their vulnerabilities have been reported since 2010. In this paper, we propose a 2.4 GHz wireless keyboard keystroke analysis and injection system based on the existing vulnerability researches of the Microsoft 2.4 GHz wireless keyboards. This system is possible to control on the remote. We also show that, via experiments using our proposed system, sensitive information of user can be revealed in the real world when using a 2.4 GHz wireless keyboard.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.5
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• pp.371-378
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• 2015

In this paper, a different type of pulse width modulation (PWM) control scheme for a buck converter is introduced. The proposed buck converter uses PWM with frequency hopping and a low quiescent.current low dropout (LDO) voltage regulator with a power supply rejection ratio enhancer to reduce high spurs, harmonics and output voltage ripples. The low quiescent.current LDO voltage regulator is not described in this paper. A three-bit binary-to-thermometer decoder scheme and voltage ripple controller (VRC) is implemented to achieve low voltage ripple less than 3mV to increase the efficiency of the buck converter. An internal clock that is synchronized to the internal switching frequency is used to set the hopping rate. A center frequency of 2.5MHz was chosen because of the bluetooth low energy (BLE) application. This proposed DC-DC buck converter is available for low-current noise-sensitive loads such as BLE and radio frequency loads in portable communications devices. Thus, a high-efficiency and low-voltage ripple is required. This results in a less than 2% drop in the regulator's efficiency, and a less than 3mV voltage ripple, with -26 dBm peak spur reduction operating in the buck converter.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.470-470
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• 2013

Recently, active materials such as amorphous silicon (a-Si), poly crystalline silicon (poly-Si), transition metal oxide semiconductors (TMO), and organic semiconductors have been demonstrated for flexible electronics. In order to apply flexible devices on the polymer substrates, all layers should require the characteristic of flexibility as well as the low temperature process. Especially, pentacene thin film transistors (TFTs) have been investigated for probable use in low-cost, large-area, flexible electronic applications such as radio frequency identification (RFID) tags, smart cards, display backplane driver circuits, and sensors. Since pentacene TFTs were studied, their electrical characteristics with varying single variable such as strain, humidity, and temperature have been reported by various groups, which must preferentially be performed in the flexible electronics. For example, the channel mobility of pentacene organic TFTs mainly led to change in device performance under mechanical deformation. While some electrical characteristics like carrier mobility and concentration of organic TFTs were significantly changed at the different temperature. However, there is no study concerning multivariable. Devices actually worked in many different kinds of the environment such as thermal, light, mechanical bending, humidity and various gases. For commercialization, not fewer than two variables of mechanism analysis have to be investigated. Analyzing the phenomenon of shifted characteristics under the change of multivariable may be able to be the importance with developing improved dielectric and encapsulation layer materials. In this study, we have fabricated flexible pentacene TFTs on polymer substrates and observed electrical characteristics of pentacene TFTs exposed to tensile and compressive strains at the different values of temperature like room temperature (RT), 40, 50, $60^{\circ}C$. Effects of bending and heating on the device performance of pentacene TFT will be discussed in detail.