• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1115-1122
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• 2003

In this paper we fabricated microchip antenna operating in bluetooth frequency bands(2.402∼2.480GHz). The antenna has a size of about 54mm${\times}419mm${\times}40.8mm, giving a total bluetooth PCB for support and chip of about 11mm${\times}44mm${\times}41.6mm. Bandwidth of the designed and fabricated chip antenna for bruetooth is 10.71 % at the resonated frequency of 2.45GHz and the resonant frequency and bandwidth versus change of any arbitrary feed point is observed. also, E-plane and H-plane in the Measured radiation pattern characteristic of chip antenna is compared and analyzed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.1
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• pp.97-102
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• 2008

A new internal antenna for GSM/DCS/Bluetooth application is proposed by using a folded loop resonator. Both feed leg and shorting leg are symmetrically implemented at the center of the folded loop, thus leading to produce resonances at integer frequencies of quarter wavelength. An open stub added at one end of the folded loop can reduce resonant frequencies. The open stub play a role in generating PIFA structure at a GSM band, thus increasing bandwidth, Two resonances at the GSM band are observed at folded ring and PIFA, respectively.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.185-188
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• 2017

본 연구는 미래 전장단말기와 무전기간 지휘관(자) 및 무전병 간 유선 연동에 따른 전투행동의 제한사항을 극복하기 위한 방법으로 강구되고 있는 무선(Bluetooth)을 이용한 데이터 전송 방법 중 Bluetooth의 세부 Profile과 전송 효율을 극대화하기 위한 최대 패킷크기, 분할 전송 간 패킷 전송 간격 등을 구체화하여 군 운용적으로 활용이 가능한지를 시험을 통해 검증하였다. 그 결과 Profile은 가장 보편적인 SPP를 적용하고, 응용계층에서 활용 가능한 최대 패킷 크기는 시험을 통해 1KB가 적정함을 확인하였다. 또한, 정지영상처럼 사이즈가 큰 데이터에 대한 분할 전송 간 패킷 전송 시간은 100ms로 설정함이 적절함을 확인하였다. 위 연구결과는 미래 전장단말기와 무전기 간 무선연동에서 즉각 적용이 가능할 것으로 판단된다.

• ETRI Journal
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• v.26 no.3
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• pp.229-240
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• 2004

This paper reports on our development of a dual-mode transceiver for a CMOS high-rate Bluetooth system-onchip solution. The transceiver includes most of the radio building blocks such as an active complex filter, a Gaussian frequency shift keying (GFSK) demodulator, a variable gain amplifier (VGA), a dc offset cancellation circuit, a quadrature local oscillator (LO) generator, and an RF front-end. It is designed for both the normal-rate Bluetooth with an instantaneous bit rate of 1 Mb/s and the high-rate Bluetooth of up to 12 Mb/s. The receiver employs a dualconversion combined with a baseband dual-path architecture for resolving many problems such as flicker noise, dc offset, and power consumption of the dual-mode system. The transceiver requires none of the external image-rejection and intermediate frequency (IF) channel filters by using an LO of 1.6 GHz and the fifth order onchip filters. The chip is fabricated on a $6.5-mm^{2}$ die using a standard $0.25-{\mu}m$ CMOS technology. Experimental results show an in-band image-rejection ratio of 40 dB, an IIP3 of -5 dBm, and a sensitivity of -77 dBm for the Bluetooth mode when the losses from the external components are compensated. It consumes 42 mA in receive ${\pi}/4-diffrential$ quadrature phase-shift keying $({\pi}/4-DQPSK)$ mode of 8 Mb/s, 35 mA in receive GFSK mode of 1 Mb/s, and 32 mA in transmit mode from a 2.5-V supply. These results indicate that the architecture and circuits are adaptable to the implementation of a low-cost, multi-mode, high-speed wireless personal area network.

• Journal of IKEEE
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• v.24 no.1
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• pp.46-51
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• 2020

With Wi-Fi and Bluetooth connectivity becoming more common in today's handheld mobile devices, single-chip multi-radio combo-modules, which integrate two or more heterogeneous wireless radios on a single chip, are becoming more and more popular. The key requirement for combo solutions is that the quality of the user experience (QoE) must not be compromised by degrading connectivity performance. Therefore, characterizing and understanding the behaviour of combo-module is of vital importance to ensure this requirement in various environments. In this paper, we investigate the impact of the use of combo-modules on the performance of mobile video streaming over a Wi-Fi network. Our study reveals that the use of combo-modules incurs considerable side effects on QoE for mobile video streaming applications when the Wi-Fi and Bluetooth operate at the same time in the 2.4GHz ISM band. We reveal that rate-based adaptive algorithms, including the most popular adaptive bitrate streaming MPEG-DASH, is more severely affected by this phenomenon than buffer-based adaptive algorithms.

• The Journal of the Korea Contents Association
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• v.4 no.1
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• pp.1-7
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• 2004

In addition to wired communication technology, wireless communication technology has been driving communication revolution nowadays. Bluetooth technology carries out data/voice communication making pico-net and the various application services are supported by access network connected to public network. This paper presents educational software development of bluetooth protocol stack including HCI, L2CAP, RFCOMM, SDP and profiles including GAP, SPP, GEOP, FTP. This software which supports programming environment of these protocol monitoring and emulation is implemented basically step by step for education based on H connected to the bluetooth device through RS-232-C, UART or USB cable. Application program coded by Visual C is operated over the firmware loaded on the bluetooth device connected to the PC. Additionally ftp and chatting function are developed to enhance educational efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.6
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• pp.1068-1075
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• 2004

The WLAN(IEEE 802.l1b) and Bluetooth(IEEE 802.15.1) employed on 2.4㎓ ISM band wireless networks provide complementary services within the same environments. Coexistence between the networks will be impaired, if the mutual packets are uncertainty associated the timing or gaussian distance. This paper analyzes the impact of the mutual interference on the services performance in order to develope a method of coexistence between the WLAN and Bluetooth. The analysis is illustrated by examining the symbol error rate versus signal to noise interference ratio in terms of the carrier frequency of set.

• Journal of Sensor Science and Technology
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• v.21 no.4
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• pp.241-248
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• 2012

Recently healthcare industry such as pharmaceutical, medical device and healthcare service technology is growing significantly. Mobile healthcare has attracted big attention due to IT convergence technology. Paradigm of healthcare has been changed from the 1st generation(communicable disease prevention) and the 2nd generation(treatment of disease due to extended life expectancy) to the 3rd generation(extended life expectancy due to prevention and control). In our study, we suggest the 3rd generation mobile healthcare system using Bluetooth based wearable ECG monitoring system and smart phone technology. The mobile healthcare system consists of wearable shirts with Bluetooth communication module, ECG sensor, battery, and mobile phone. The ECG data is obtained by a miniaturized sensor and the data is transferred to a mobile phone using Bluetooth communication. Then, user can monitor his/her own ECG signal on an application using Android in mobile phone. The Bluetooth communication device is used due to highly reliable data transmission property and the Bluetooth chip is embedded in every mobile phone. The wearable shirts with chest belt of Bluetooth ECG module is designed with a focus on convenience in the daily life of a wearer. The ECG signal evaluation software in Android based mobile phone is developed for the health check and the ECG signal variation is tested according to the activities of the wearer such as walking, climbing stairs, stand up and sit down, and so on.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.435-443
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• 2020

We analyzed whether the use of the Bluetooth salinity meter could affect the proper level of salinity in childcare centers. This study was conducted on childcare centers that wish to participate in the sodium reduction project (Bluetooth salinity meter using group, BG) and those that did not participate (Bluetooth salinity meter not using group, NG) among childcare centers registered with Center for Children's Foodservice Management in Anyang from January to December 2019. As a result of comparing the salinity and sodium contents of the soup according to whether or not a Bluetooth salinity meter was used, the salinity and sodium contents of BG was significantly lower than that of NG (p < 0.0001). Salinity and sodium contents in soups tended to decrease as the number of use of the Bluetooth salinity meter increased (p = 0.020). In conclusion, Bluetooth salinity meter can be used as a means to induce voluntary salinity control by cookers regarding sodium reduction education at childcare centers.

• Journal of information and communication convergence engineering
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• v.4 no.1
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• pp.13-17
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• 2006

In this paper a design and implementation method of remote control system for automobile is presented. For this, we used the Bluetooth technology for remote and wireless communications and microcontroller for system control. By using these techniques, we can design and implement automobile remote control system to improve data error rate, security and application.