• JSTS:Journal of Semiconductor Technology and Science
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• v.4 no.3
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• pp.210-216
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• 2004

In this paper, we propose a noncoherent On-Off Keying (OOK) Ultra Wide Band (UWB) system based on power detection with noise power calibration for low power applications. The proposed UWB system achieves good bit error rate performance which is favorably comparable to that of the system using the ideal adaptive threshold, while maintaining simple receiver structure, In addition, low power Analog Front-End (AFE) blocks for the proposed noncoherent UWB transceiver are proposed and verified using CMOS technology. Simulation results on the pulse generator, delay time generator and 1-bit Analog-to-Digital (AID) converter show feasibility of the proposed UWB AFE system.

• New & Renewable Energy
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• v.20 no.1
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• pp.116-125
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• 2024

Ultra-low-head is an unexplored classification among the sites in which hydroelectric power can be produced. This is typically owing to the low power output and the economic value of the turbines available in this segment. A turbine capable of operating in an ultra-low-head condition without the need of a dam to produce electricity is developed in this study. A gate structure installed at a shallow water channel acting as a weir generates artificial head for the turbine mounted on the gate to produce power. The turbine and generator are designed to be compact and submersible for an efficient and silent operation. The gate angle is adjustable to operate the turbine at varying flow rates. The turbine is designed and tested using computational fluid dynamics tools prior to manufacturing and experimental studies. A parametric study of the runner blade parameters is conducted to obtain the most efficient blade design with minimal hydraulic losses. These parameters include the runner stagger and runner leading edge flow angles. The selected runner design showed improved hydraulic characteristics of the turbine to operate in an ultra-low-head site with minimal losses.

• Transactions on Semiconductor Engineering
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• v.2 no.1
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• pp.9-16
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• 2024

This paper discusses the design of bio-implanted ultra-low-power MICS RF transceivers for wireless sensor networks. The 400 MHz MICS standard was considered for the implementation of the WBAN wireless sensor system, indirectly minimizing radio propagation losses in the human body and the inference with surrounding networks. This paper includes link budget, various transmission and reception architectures for a system design and ultra-low power transceiver circuit techniques for the implementation of RF transceivers that meet MICS standards.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.3
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• pp.199-204
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• 2021

Ultra-compact electric vehicles have narrow space for power conversion devices. This work presents schemes to achieve the high-power density of a low-voltage DC-DC converter (LDC): simplifying a converter structure by using sync-buck topology, applying a planar inductor using PCB winding, and applying a plate-type heat sink. The heat sink is placed between two PCBs, which increases the contact surface between the PCB and the heat-dissipating device. It enables the miniaturization of the converter to improve the conditions of heat radiation. The validity of the proposed scheme is verified through the experiment using a 500 W(12 V, 41.67 A) prototype with an input voltage range from 58 V to 84 V.

• Journal of IKEEE
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• v.12 no.1
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• pp.27-33
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• 2008

The demand of wireless communication is increased rapidly due to the development of wireless communication systems, and many people have the great interest about the "RF system". The trend of the RF audio system is to design the system with less power consumption. In this paper, we explain the Software Algorithm Design of RF systems that is suitable for low power consumption.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10C
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• pp.992-998
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• 2005

In this paper, An Ultra Fast Acquisition Algorithm of low transmission rate ultra-wideband(UWB) systems for car positioning and traffic light controling is proposed. Since the acquisition algorithms for CDMA system are not fast enough to access the low transmission rate UWB systems, the new ultra fast acquisition scheme which can be implemented with low cost and simplified circuit is required. The proposed algorithm adopted the Recurrent Sequential Estimation scheme and trinomial M-sequence. Therefore, The proposed scheme can reduce the average acquisition time in $1\~3{\mu}sec$ with simple circuit, even for the UWB systems which use long pseudo-noise(PN) sequence and transmit low power below the FCC EIRP emission limits. The simulation results for the average acquisition time of the proposed scheme are compared with the ones of the existing acquisition schemes.

• Journal of Power System Engineering
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• v.17 no.6
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• pp.115-121
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• 2013

This study was carried out to investigate the effect of hot forging on the hardness and impact value of ultra high carbon low alloy steel. With increasing hot forging ratio, thickness of the network and acicular proeutectoid cementite decreased, and than were broken up into particle shapes, when the forging ratio was 80%, the network and acicular shape of the as-cast state disappeared. Interlamellar spacing and the thickness of eutectoid cementite decreased with increasing forging ratio, and were broken up into particle shapes, which then became spheroidized. With increasing hot forging ratio, hardness, tensile strength, elongation and impact value were not changed up 50%, and then hardness rapidly decreased, while impact value rapidly increased. Hardness and impact value was greatly affected by the disappeared of network and acicular shape of proeutectoid cementite, and became particle shape than thickness reduction of proeutectoid and eutectoid cementite.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.4
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• pp.44-49
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• 2017

There are many battery-based wearable devices for healthcare and medical applications, but there is a user's inconvenience to charge battery frequently due to insufficient power management. In this paper, we propose a tickless-based operating system and power management algorithm that can effectively utilize the power management provided by HW, and propose a cold restart method that consumes the minimum power at the board level. The operating system of the proposed technique has reduced the power consumption from 2 times to 33 times in the four scenarios modeling the wearable device application compared to the existing operating system.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.4
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• pp.405-411
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• 2020

In this paper, we designed the COS MEMS system for sensing the falling detection and explosive noise of fuse link in COS (Cut Out Switch) installing on the power distribution. This system analyzed the failure characteristics and an instantaneous breakdown of power distribution. Therefore, our system strengths the industrial competence and guaranties the stable power supply. In this paper, we applied BLE (Bluetooth Low Energy) technology which is suitable protocol for low data rate, low power consumption and low-cost sensor applications. We experimented with LSM6DSOX which is system-in-module featuring 3 axis digital accelerometer and gyroscope boosting in high-performance mode and enabling always-on low-power features for an optimal motion for the COS fuse holder. Also, we used the MP34DT05-A for gathering an ultra-compact, low power, omnidirectional, digital MEMS microphone built with a capacitive sensing element and an IC interface. The proposed COS MEMS system is developed based on nRF52 SoC (System on Chip), and contained a 3-axis digital accelerometer, a digital microphone, and a SD card. In this paper of experiment steps, we analyzed the performance of COS MEMS system with gathering the accelerometer raw data and the PDM (Pulse Data Modulation) data of MEMS microphone for broadcasting the failure of COS status.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8A
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• pp.661-668
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• 2012

In this paper, we introduce the low power wireless communication method and propose new protocol and algorithm for wireless communication which can be applied Active RFID system. Transceiver module is composed of MCU, RF transceiver and chip antenna. and it used the lithium coin battery for power supply. The experimental result is confirmed minimum power consumption which show average $10{\mu}A$(packet transmit) and $30{\mu}A$(packet receive) per second. It can be used ultra low power wireless communication. this result is possible for using the algorithm which predict the arrival time of packet. and it indicates that are possible to prevent malfunction and enhance responsiveness.