• 한국컴퓨터산업교육학회:학술대회논문집
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• 2003.11a
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• pp.99-102
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• 2003

Data acquisition of biomedical signal is important that can convert health of human body to measurable datas. In this paper, we developed system that can send multiple ECG data, ECG signal in biomedical signals, using Bluetooth wireless transmission. Developed system has several features, total gain of 1000, filtering data for noise reduction in hardware / software parts, portable to carry cause it has small size and battery operation. And system was designed which can measures data in several OS(Windows 2000, Windows CE).

• The Journal of Korean Association of Computer Education
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• v.14 no.6
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• pp.83-89
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• 2011

In this study a smart HDMI switch is proposed to detect newly formed video stream and automatically change the transfer path to the corresponding port without pulling the HDMI plug and putting it again in the desired port manually and physically. Furthermore the proposed switch is designed in the advanced wireless video transmission scheme based on millimeter band technology. The proposed system shows its feasibility by the hardware experiment in the full-HD video transmission performance including the function of the smart port change.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.449-452
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• 2005

For home networking system with a function of air quality monitoring, a wireless sensor module with several air quality monitoring sensors was developed for indoor environment monitoring system in home networking. The module has various enlargements for various kinds of sensors such as humidity sensor, temperature sensor, CO2 sensor, flying dust sensor, and etc. The developed wireless module is very convenient to be installed on the wall of a room or office, and the sensors in the module can be easily replaced due to well designed module structure and RF connection method. To reduce the system cost, only one RF transmission block was used for sensors' signal transmission to 8051 microcontroller board in time sharing method. In this home networking system, various indoor environmental parameters could be monitored in real time from RF wireless sensor module. Indoor vision was transferred to client PC or PDA from surveillance camera installed indoor or desired site. Web server using Oracle DB was used for saving the visions by web-camera and various data from wireless sensor module.

• Journal of Satellite, Information and Communications
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• v.10 no.1
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• pp.88-91
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• 2015

Wireless power transmission (WPT) is a technology using free space as a conductor for transmitting electric power, which aims to transfer not just the transmission signal but also the electrical energy itself. This paper takes issue with the microwave wireless transmission technology utilizing in long-distance transmission. To construct the WPT system, several components are needed, such as RF Oscillator which converts AC power to RF through DC status, high gain antenna and RF rectifier that converts RF back to DC. The array topology is good a candidate for wide use. The objective of this research is to study the efect of the WPT systmem on electric power system.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.1
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• pp.166-171
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• 2012

In this paper, short-range underwater wireless communication technique using visible LEDs is proposed. As an alternative to conventional acoustic system, visible LED communications show high quality and high speed data transmission characteristics. We design a frequency modulation-based optical wireless audio transmission system. The CD4046B phase-locked loop device is applied to implement the frequency modulation and demodulation. With a transmission modulation of 100 kHz, audio signal has successfully received at a transmission distance of 30 cm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.4050-4067
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• 2014

In wireless sensor networks, link scheduling is a fundamental problem related to throughput capacity and delay. For a given set of communication requests $L=\{l_1,l_2,{\cdots},l_n\}$, the MLS (maximum link scheduling) problem aims to find the largest possible subset S of Lsuch that the links in S can be scheduled simultaneously. Most of the existing results did not consider bidirectional transmission setting, which is more realistic in wireless sensor networks. In this paper, under physical interference model SINR (signal-to-noise-plus-interference-ratio) and bidirectional transmission model, we propose a constant factor approximation algorithm MLSA (Maximum Link Scheduling Algorithm) for MLS. It is proved that in the same topology setting the capacity under unidirectional transmission model is lager than that under bidirectional transmission model. However, compared with some work under unidirectional transmission model, the capacity of MLSA is improved about 28% to 45%.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.55-58
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• 2002

This paper describes an RF module for 2.4GHz wireless audio/video transmission. The pre-processed baseband input signals are FM-modulated using a VCO and then transmitted through an antenna after RF filtering. The designed circuits are implemented using a Teflon board of which the size is 52mm${\times}$62mm. The measured maximum output signal levels are around -3dBm and the harmonics are less than -450dBc. The manufactured module consumes 130mA from a 8V supply.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.4
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• pp.506-511
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• 2011

In this paper, a rectenna for wireless power transmission at 900MHz is proposed. Rectenna is a device transforming RF power into DC power and it may consist of a antenna, rectifying and charging circuits. In this paper, we designed a slot antenna to receive 900MHz signal, a rectifying circuit of about 40% efficiency at 0dBm input, and a charging circuit to store a weak power signal and supply constant voltage to load. From the experiment using a RFID reader as a transmitter for 1W power, it was found that the proposed rectenna receiving about 0dBm power can supply 3.3V constant voltage to 50$k{\Omega}$ load during 280sec.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.5
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• pp.416-425
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• 2002

In this Paper, It is analysed 5 GHz frequency characteristics that carry out interference experimental under the indoor environments for understanding propagation interference between existing 5 GHz band wireless communication system and 5 GHz band wireless LAN system. The interference signal which was generated by signal generator injected to 5 GHz Wireless LAN communication system measured interference characteristics and This radio propagation main interference factors were classified received power level separation by interference source frequency and interference source frequency pulse period & width separation. It is measured transmission rate according to variable data and packet size for conforming the quality of 5 GHz band wireless LAN system. We measured the packet data loss rate and power level of received signal and analyzed its frequency characteristics effected by interference signal.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.2
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• pp.37-43
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• 2009

Reliability should be assured to support the stable ubiquitous sensor network services in wireless sensor networks. Data transmission reliability is the most important one in the reliability factors in USN. When we consider the wireless communication environment of sensor networks, data transmission reliability requires the performance improvement. For this, this paper introduces the method that can handle the reliability and the performance together. The proposed scheme uses the self relay signal between sensor nodes to deliver the ACK and the next data is scheduled to be sent on acceptance of this self relay signal. For the evaluation of the performance improvement, the analysis and the simulation have been done.