• International Journal of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.330-338
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• 2024

In this paper, a Ka-band high-output active phased array antenna device applicable to small radars and seekers was designed, and the improved performance was studied. The radiation device assembly consists of 1x8 arrangements, and the step flared notch antenna type. It shows low active reflection loss characteristics in broadband, and low loss characteristics by applying the air-strip feeding structure, and is designed to enable beam steering up to 45 degrees. The TRM(transmit receive module) output power is more than 2.0W per channel using GaN HPA in the transmitting path, and satisfies more than 25.0 dB gain and less than 6.0 dB noise figure in the receiving path. Accordingly, the Effective Isotropically Radiated Power(EIRP) of the antenna unit shows the performance of 0.00 dB or more and the receive gain-to-noise temperature ratio(G/T) of 0.00 dB/k or more. For demonstration, we have designed aforementioned planar array antenna which consists of 64 radiating elements having a size within 130 mm x 130 mm x 300 mm and weight of less than 4.9 kg..

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.69-74
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• 2005

The High Peak to Average Power Ratio (PAPR) could be a severe Problem in OFDM performance since it causes the significant distortion to the transmitting signal through a nonlinear device such as High Power Amplifier (HPA). In this paper, the performance of Peak cancellation method according to the HPA characteristic is comparatively analyzed with the clipping and windowing methods. The BER performances and the out-band power spectrums are demonstrated in detail.

• Journal of Biosystems Engineering
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• v.32 no.4
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• pp.223-229
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• 2007

This study was conducted to develop a 2 row type band furrow tiller for a walking cultivator. The tillage and weeding operations in the furrow of dry fields has been done manually or chemical herbicide has been applied. The application of herbicide induces soil pollution and manual operation requires heavy labor. This 2-row type implement was developed to substitute this manual operation and to minimize soil pollution. The developed implement was composed of power transmitting device, tilling device, frame and tail wheel. The max. plowing width and depth were 300mm and 180mm, respectively. The revolutions of the hexagonal shaft and the tillage shaft were $227{\sim}376rpm$ and $355{\sim}590rpm$, respectively. The adequate working speed was $0.50{\sim}0.83m/s$ and the field capacity was $0.17{\sim}0.28hr/10a$.

• Journal of Advanced Information Technology and Convergence
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• v.10 no.1
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• pp.57-69
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• 2020

In general, many IoT devices, including smart phones, use LTE, Wi-Fi, and Bluetooth, and these communication modules generate a lot of energy consumption during periodic data transmission. This paper proposes a method of the data transmission mode change for improving energy efficiency in various communication environments that mobile devices may encounter. We propose an algorithm for setting the mode considering energy efficiency, data transmission performance and cost when the mobile device transmits data, and transmitting the data in an optimized manner according to the state of the mobile device. The proposed algorithm is implemented through experiments on energy efficiency for each communication module, and the scenario is used to verify how efficiently the proposed algorithm uses energy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11B
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• pp.792-803
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• 2005

Ultra wide band (UWB) technology will be applied in the high rare wireless personal area networks (WPANs) for its high rate, low power, and innate immunity to multipath fading. In this paper, a power aware multi-hop packet relay MAC protocol in UWB based WPANs is proposed and a power aware path status factor (PAPSF), which is derived from SINR and power resource condition of each device, is used to select a suitable relay node. Compared with relaying by piconet coordinator (PNC), which is easily chosen by other ad hoc routing protocol, the new scheme can achieve hi임or throughput, decrease the time required for transmitting high power signal and we can easily distribute the battery power consumption from PNC to other devices in the piconet to prevent the PNC device using up its battery too fast and finally avoid PNC handover too frequently.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.3
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• pp.35-40
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• 2024

In this paper, the design, implementation, and analysis of a device capable of transmitting and receiving millimeter-wave signals and performing channel sounding measurements in atmospheric conditions at distances of up to approximately 10km outdoors are presented. The device is expected to be instrumental in studying the propagation characteristics of millimeter-wave frequencies. Utilizing data such as received power levels and power delay profiles (PDPs), comparisons with predicted values using path loss, K-factor, and other propagation models are facilitated. The mobile transceiver unit, integrated onto a vehicle platform, allows for flexible adjustment of transmitter and receiver positions, while synchronization issues with distance are mitigated using a rubidium atomic clock. Furthermore, automatic boresight alignment using scanning techniques is employed to locate the main sector of the antenna.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.3
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• pp.469-478
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• 2022

This paper contains the results of developing smart devices and applications to monitor the load power of the industrial manufacturing machine and evaluate its performance. The smart devices in this paper are divided into two functionalities, which are collecting load power along with operating environment data of industrial manufacturing machines and transmitting the data to servers. Load power data collected from the smart devices are uploaded to MariaDB inside the Amazon Web Service (AWS) server. Using the RESTFul API, the uploaded power data can be retrieved and shown on the web and mobile application in the form of a graph to provide monitoring capability. To evaluate the performance of the developed system, the response time from MariaDB to web and mobile applications was measured. The results is ranging from 0.0256 to 0.0545 seconds in a 4G (LTE) network environment and from 0.6126 to 1.2978 seconds in a 3G network environment, which is considered a satisfactory result.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.761-764
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• 2010

Interest in vehicle infotainment system, that provides both entertainment of driving and information for safe and convenient driving, has been recently increased. MOST is defined as the network transmitting high-bandwidth infortainment data to vehicle, and it has been standardized as MOST150. In this research, dynamic behavior method that deals with roles and functions of each devices connected to MOST150 Network, and Power Management Method was studied. MOST Network consists of a master device, including function block 'NetworkMaster', and all other devices called slave devices. The purpose of this study is to apply the analysis of the methods of operating and power management based on condition of master device and slave devices on MOST150 network to the future development of MOST150 devices.

• Journal of Advanced Navigation Technology
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• v.27 no.2
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• pp.221-227
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• 2023

In this paper, by using a multi-PLUTO SDR platform, we implement a beamforming wireless power transmission test bed capable of beam alignment for the receiving end by calculating the location information of the target device (power receiving platform) in a situation where power transmitting and receiving platforms do not know each other's location information. Experiments were conducted in a laboratory environment based on the built test bed, and the experimental results were compared with the simulation results to confirm both whether the testbed was effectively configured and the performance effectiveness of the test bed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.820-826
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• 2011

In this paper, an efficiency improvement method in the wireless power transfer system based on magnetic resonance is proposed. A combined helical-spiral structure is adopted for self-resonant coil and source and device coils are designed using circular loop structure. The proposed resonator utilizing combined helical-spiral structure yields 13 % efficiency improvement over that of an existing helical type resonator when the transmitting and receiving coils are separated by 120 mm. In addition, the size can be reduced by 33 % comparing to the previous resonator.