• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.2
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• pp.67-74
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• 2009

In this paper, the multi-band antenna with CPWG(Coplanar Waveguide with Ground) feed for telematics mobile devices is designed and fabricated. The proposed antenna improves the return loss characteristic by using open-circuited stub matching and rectangular slot in the radiation patch. In addition, CPWG structure makes up for the drawback of the CPW which is variation of impedance matching according to the gap variation of the feed line and the ground. The fabricated antenna has 1.4GHz ($1.43GHz{\sim}2.83GHz$, 65%) band width on -10dB (VSWR<2) and the maximum gains are 0.8dBi, 1.34dBi, 2.41dBi, 2.53dBi, 2.6dBi and 1.51dBi on each resonant frequency that are GPS $(1.564GHz{\sim}1.585GHz)$, PCS/DCS $(1.710GHz{\sim}1.984GHz)$, WCDMA $(2.170GHz{\sim}2300GHz)$, Bluetooth/Wi-Fi/WLAN $(2.4GHz{\sim}2.483GHz)$, WiBro $(2.3GHz{\sim}2.4GHz)$, SDMB $(2.605GHz{\sim}2.655GHz)$. It also has an omni-directional radiation pattern of H-Plane.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.6
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• pp.63-69
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• 2008

Reconfigurable RF one-chip solutions have been researched with the objective of designing for smaller-sized and more economical RF transceiver and it can be applied to a vehicular wireless terminal. The proposed voltage-controlled oscillator satisfies the targeted frequency range ($4.2{\sim}5.4\;GHz$) and the frequency planning which correspond to the standards such as CDMA(IS-95), PCS, GSM850, EGSM, WCDMA, WLAN, Bluetooth, WiBro, S-DMB, DSRC, GPS, and DVB-H/DMB-H/L(L Band). In order to improve phase noise performance, PMOS is adopted in the cross-coupled pair, the tail current source and MOS varactor in this VCO and differential-typed switching is proposed in capacitor array. Based on the measurement results, a total power dissipation is $5.3{\sim}6.0\;mW$ at 1.8 V power supply voltage. The oscillator is tuned from 4.05 to 5.62 GHz; The tuning range is 33%. The phase noise is -117.16 dBc/Hz at 1 MHz offset frequency and the FOM (Figure Of Merit) is $-180.84{\sim}-180.5$.

• Review of KIISC
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• v.26 no.3
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• pp.50-57
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• 2016

최근 사물인터넷(IoT) 시장의 급격한 성장과 함께 적용 서비스 분야도 급격하게 늘어나고 있다. 다양한 객체와 인터넷의 연결로 무수히 많은 서비스가 제공되고 있으며 기업 및 공공기관은 이를 활용하여 다양한 콘텐츠를 개발하고 있다. 하지만 IoT인프라의 급격한 범위 확장 및 활용 표준화가 이루어지지 않았고, 이에 따라 인프라 프로세스의 혼란을 야기할 수 있다. 이는 내 외부적인 위협의 증가로 이어진다. 따라서 사물인터넷 기술이 현재 시장보다 활성화 되고 실 서비스 적용 분야가 증가할수록 제도적, 물리적, 기술적인 취약점이 원인이 되어 공격자는 사물인터넷 단말기 내부에 악성코드를 심어 원격 통제를 하거나, 일정 무선 주파수를 동기화 하여 스니핑이나 스푸핑 등의 공격으로 데이터 변조의 위협이 존재한다. 본 연구를 통해 콘텐츠 정보제공의 주 목적으로 활용되는 미들웨어장비인 Bluetooth 4.0 기반의 저전력 비콘(Beacon)의 기능을 활용한 서비스에서 발생될 수 있는 내재적 위협으로부터 정책적, 기술적, 물리적 통제 및 대응 방안을 제안하였다.

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.37-38
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• 2015

최근 안드로이드 4.0 이상 버전에서 저전력 블루투스(Bluetooth Low Energy) 기능이 지원되면서, 다양한 응용사례가 나타나고 있다. 이러한 BLE 프로토콜을 활용하는 Sensor-Tag IoT 센서노드를 활용하면 스마트홈, 웨어러블, 스마트카, 생활밀착 서비스, 스마트에너지, 산업 및 환경분야에서 다양한 스마트폰 앱을 개발할 수 있다. 또한, BLE-스택(Stack)TM 소프트웨어를 사용하면, 라이센서 걱정없이 펌웨어 소스코드의 개발 및 업데이트가 가능하다. 따라서, 다양한 센서가 장착된 IoT Sensor 노드를 통하여, 습도/온도/가속도/지자기/자이로 등의 데이터를 수집하여 활용할 수 있다. 이에 본 논문에서는 "저전력 센서 노드를 사용한 IoT 서비스 설계 프레임워크"를 제안한다.

• International Journal of Advanced Culture Technology
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• v.6 no.3
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• pp.216-225
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• 2018

Strangely enough, there has not been much effort in applying the latest technologies to help referees make accurate calls in a soccer game compared to other sports. Modern soccer tries to apply VAR (Video Assistant Referee) technology to correct inaccurate calls such as an offside, but this is being put off due to the fact that real time decision-making cannot be carried out by using this technology. This has led this study to decide developing a device that will accurately identify offsides on a real time basis using various latest sensors and related technologies. This device will aid referees in calling offsides in a soccer match.

• Journal of Korean Society of Disaster and Security
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• v.9 no.1
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• pp.33-38
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• 2016

Real time location system was development for safety management at road and bridge maintenance field. The system can check the real-time location detection, movement history, behavior of a number of laborers. The system consisted of a Bluetooth and ZigBee that uses low-power. It had a very large error that the previous method for the position recognition by triangulation using the RSSI. Because This study proposed a new distance measurement and correction scheme using RSSI and accelerometer. It was evaluated in the maintenance field. A development system were evaluated in the field, the results are shown an error between 0.2 m and 0.4 m. And through the acceleration of history it was confirmed by determining possible to determine the safety situation of the laborers.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.3
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• pp.164-168
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• 2016

A low insertion-loss, high-isolation switch based on single pole double throw (SPDT) for a 2.4GHz Bluetooth low-energy transceiver is presented in this paper. In order to increase isolation, the body floating technique is implemented. Based on characteristics whereby the ratio of the sizes of the shunt and the series transistors significantly affect the performance of the switches, the device sizes are optimized. A simple matching network is also designed to enhance the insertion loss. Thus, the SPDT switch has high isolation and low insertion loss without increasing the complexity of the circuit. The proposed SPDT is designed and simulated in a complementary metal-oxide semiconductor 65nm process. The switch has a $530{\mu}m{\times}270{\mu}m$ area and achieves 0.9dB, 1.78dB insertion loss and 40dB, 41dB isolation of transmission, reception modes, respectively.

• Journal of the Korea Safety Management & Science
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• v.21 no.4
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• pp.51-58
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• 2019

The LBS(Location Based Service) technology plays an important role in reducing wastes of time, losses of human lives and economic losses by detecting the user's location in order by suggesting the optimal evacuation route of the users in case of safety accidents. We developed an algorithm to estimate indoor location, movement path and indoor location changes of smart phone users based on the built-in sensors of smartphones and the dead-reckoning algorithm for pedestrians without a connection with smart devices such as Wi-Fi and Bluetooth. Furthermore, seven different indoor movement scenarios were selected to measure the performance of this algorithm and the accuracy of the indoor location estimation was measured by comparing the actual movement route and the algorithm results of the experimenter(pedestrian) who performed the indoor movement. The experimental result showed that this algorithm had an average accuracy of 95.0%.

• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.495-502
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• 2005

Cryptographic algorithm testing is performed to ensure that a specific algorithm implementation is implemented correctly and functions correctly. CMVP(Cryptographic Module Validation Program) of NIST in US is the well-known testing system that validates cryptographic modules to Federal Information Processing Standards (FIPS). There is no FIPS-approved stream cipher, and CMVP doesn't involve its validation testing procedure. In this paper we provide validation systems for three currently used light-weight stream ciphers: Bluetooth encryption algorithm E0, 3GPP encryption algorithm A5/3, and RC4 used for WEP and SSL/TLS Protocols. Moreover we describe our validation tools implemented by JAVA programing.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.531-532
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• 2016

Carpal tunnel syndrome, carpal tunnel becomes part of a narrower median nerve pain occurs pressed. How a stable wrist stretch for the prevention of carpal tunnel syndrome is required, it should life guides to fit the user is provided. In this research, users themselves recognize the risk of carpal tunnel syndrome, to be able to stretch, it implements the application. Application, based on the usage time set by the user, executes the alarm and lock. At this time, the user may utilize arduino and inertia sensor, it is possible to wrist stretch, to analyze usage patterns, it is possible to provide a medical information and life guides to suit the user. Data using Bluetooth 4.0 communication has been to meet the runaway. In order to evaluate the mounted system, targeting four subjects, the time and the touch frequency of usage of the 3-day smartphone measured, as a result of the questionnaire, it reduces the frequency of use of smartphones, a positive it was possible to prove the effect.