• International conference on construction engineering and project management
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• 2005.10a
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• pp.1199-1202
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• 2005

Knowledge has been considered one of the important elements that determine our future. Competitive power of an enterprise has also been transformed from labor, capital, and technology-oriented to knowledge-oriented. Current construction environment is experiencing overall decrease of number of construction contracts due to opening of domestic construction market and economic slump, problems on methods of receiving orders/bidding, and change of costumers' attitude, which intensify competition, therefore many companies consider adopting knowledge management to secure their competitive power. However, there are difficulties in adopting knowledge management and increasing the use by establishing management plan, Performance Measurement, and knowledge maintenance system in reality. Therefore, this study is to provide assistance to successful realization of knowledge management by suggesting development plan of knowledge management that enables knowledge management more efficient with certain goals.

• Journal of Sensor Science and Technology
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• v.31 no.3
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• pp.139-144
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• 2022

Advanced tactile sensors are receiving significant attention in various industries such as extended reality, electronic skin, organic user interfaces, and robotics. The capabilities of advanced tactile sensors require a variety of functions, including position sensing, pressure sensing, and material recognition. Moreover, they should comsume less power and be bio-friendly with human contact. Recently, a tactile sensor based on the triboelectrification effect was developed. Triboelectric tactile sensors have the advantages of wide material availability, simple structure, and low manufacturing cost. Because they generate electricity by contact, they have low power consumption compared to conventional tactile sensors such as capacitive and piezoresistive. Furthermore, they have the ability to recognize the contact material as well as execute position and pressure sensing functions using the triboelectrification effect. The aim of this study is to introduce the progress of research on triboelectrification-based tactile sensors with various functions such as position sensing, pressure sensing and contact material recognition.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.3
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• pp.263-267
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• 2014

Super junction trench gate power MOSFETs have been receiving attention in terms of the trade-off between breakdown voltage and on-resistance. The vertical structure of super junction trench gate power MOSFETs allows the on-resistance to be reduced compared with conventional Trench Gate Power MOSFETs. The heat release of devices is also decreased with the reduction of on-resistance. In this paper, Lattice Temperature of two devices, Trench Gate Power MOSFET and Super junction trench gate power MOSFET, are compared in several temperature circumstance with the same Breakdown Voltage and Cell-pitch. The devices were designed by 100V Breakdown voltage and measured from 250K Lattice Temperature. We have tried to investigate how much temperature rise in the same condition. According as temperature gap between top of devices and bottom of devices, Super junction trench gate power MOSFET has a tendency to generate lower heat release than Trench Gate Power MOSFET. This means that Super junction trench gate power MOSFET is superior for wide-temperature range operation. When trench etching process is applied for making P-pillar region, trench angle factor is also important component. Depending on trench angle, characteristics of Super junction device are changed. In this paper, we focus temperature characteristic as changing trench angle factor. Consequently, Trench angle factor don't have a great effect on temperature change.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.1
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• pp.1-16
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• 2023

Recently, the shift to next-generation wide-bandgap (WBG) power semiconductor for electric vehicle is accelerated due to the need to improve power conversion efficiency and to overcome the limitation of conventional Si power semiconductor. With the adoption of WBG semiconductor, it is also required that the packaging materials for power modules have high temperature durability. As an alternative to conventional high-temperature Pb-based solder, Ag sintering die attach, which is one of the power module packaging process, is receiving attention. In this study, we will introduce the recent research trends on the Ag sintering die attach process. The effects of sintering parameters on the bonding properties and methodology on the exact physical properties of Ag sintered layer by the realization 3D image are discussed. In addition, trends in thermal shock and power cycle reliability test results for power module are discussed.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.5
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• pp.412-417
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• 2013

Analytical modeling of photovoltaic power systems has been receiving significant attentions in recent years in that it is easy to apply for prediction of its dynamics and fault detection and diagnosis in advanced engineering technologies. This paper presents a novel probabilistic modeling approach for such power systems with a big data sequence. Firstly, we express input/output function of photovoltaic power systems in which solar irradiation and ambient temperature are regarded as input variable and electric power is output variable respectively. Based on this functional relationship, conditional probability for these three random variables(such as irradiation, temperature, and electric power) is mathematically defined and its estimation is accomplished from ratio of numbers of all sample data to numbers of cases related to two input variables, which is efficient in particular for a big data sequence of photovoltaic powers systems. Lastly, we predict the output values from a probabilistic model of photovoltaic power systems by using the expectation theory. Two case studies are carried out for testing reliability of the proposed modeling methodology in this paper.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.339-346
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• 2011

In the existing RF communication based WPAN environment, a lowering of battery span and interference problem among sensors occur because the value of output is set and transmitted steadily when the system on sensor is initialized. Therefore, this paper proposes a framework and a transmit method with low power which decreases the electricity consumption by properly controling transmit power of opponent by received signal strength indicator(RSSI) of each sensor. The system proposes a power-lowering method by controling transmit power properly by the transmit intensity of the connected sensor after being affected by the transmit intensity of surrounded sensor. The framework that is proposed in this paper includes data transmit module, transmit power manager module, transmit power searching module, signal transmit module, and signal receiving module.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.210-215
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• 2006

In this paper, we develop the PLL system of the local oscillator system using Gunn oscillator VCO for millimeter wave band receiving system. The local oscillator system consists of the $86{\sim}115GHz$ Gunn. diode oscillator part, the RF processing part including the diplexer and the harmonic mixer, and the DPLL system including Gunn modulator and controller. Based on this configuration, we verify the frequency and power stability of the developed local oscillator system. We developed system which applied to DPLL technique instead of the existing analog PLL method to accomplish this purpose. The developed system for this purpose is tested the frequency and power stability for a long time to confirm performance. Since we confirmed this system that had frequency characteristic of within ${\pm}10Hz$, very fine output drift power characteristic of $0.2{\sim}0.3dBm$ and about 200MHz locking range, it verified suitable for cosmic radio receiving system through the test result.

• Journal of Advanced Navigation Technology
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• v.21 no.4
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• pp.413-421
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• 2017

In this paper, we designed and fabricated a compact UHF receive module for efficient operation such as tactical and operation situation, target location information confirmation, target reset using Link-K(Korean joint tactical data link system). And the effect of target reset was analyzed by simulation. The designed module consists of UHF(ultra high frequency) receiver section, control section, and power distribution section. The UHF receiver section performs frequency down conversion, filtering and automatic gain control, etc. The control section demodulates frequency down-converted signals, extracts information, and performs external interworking. The power distribution section supplies external power, generates and supplies the power required by each section. The fabricated module was dimension of $105{\times}105{\times}80mm$ and weighed 1.10 kg and The receiving distance is more than 50 km.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.31-38
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• 2003

Among mitigation techniques for electric and magnetic field (EMF) from an overhead transmission line a passive loop is a way that can be cheap and easily installed on the existing towers and have a satisfactory effect as well. However current induced in the passive loop causes transmission power loss and the phase imbalance increases since geometrical asymmetry of the transmission lines becomes larger. So in order to evaluate the power loss and the phase imbalance due to a passive loop, this paper represent a 345[kV] 1-circuit flat type transmission line as asymmetrical 3-phase distributed parameter line model where the effect of a passive loop is embedded in the line parameters, and then formulates differential equations. By solving these equations voltages and currents of each phase at receiving end become known. We find out that power losses occur differently at each phase and positive sequence component decreases at receiving end while negative sequence component increase. In general phase imbalance due to a passive loop is slight, but it increases in proportional to the induced current and length of section where the passive loop is installed. Thus the phase imbalance should be included in terms of cost for introducing a passive loop.

• Journal of Broadcast Engineering
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• v.21 no.1
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• pp.97-104
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• 2016

In this paper, in order to relieve the area of terrestrial DTV broadcasting, we watch the same channel DTV Repeater output ICS using nano field test and analysis of effect was proven. Interspersed throughout the blanket area(natural) and buildings(artificially) 7 established the field selected as the test area, and each station(KBS1, KBS2, MBC, SBS, EBS) Extremely Low Power ICS Repeater the same channel of the receiving field strength and after install, SNR(Signal to Noise Ratios) verify the equipment to measure the efficacy and minimal output for future ICS type nav should you wish to provide a research-based for the spread.