• Smart Structures and Systems
• /
• v.7 no.1
• /
• pp.27-40
• /
• 2011

Geopolymer concrete is finding a growing number of niche applications in the field of civil engineering due to its high compressive strength and strength gain rate, retainage of structural properties in elevated temperature environments, chemical stability in highly acidic conditions and environmental benefits. Combining the above mentioned characteristics with induced electrical conductivity, could enable geopolymer cement to serve as a smart and sustainable cementitious material suitable for health monitoring of civil structures. Carbon fibers were added to fresh geopolymer and OPC (ordinary Portland cement) mixes to enhance their electrical conductivities. AC-impedance spectroscopy analysis was performed on the specimens with fiber fraction ranging from 0.008 to 0.8 with respect to the weight of cementitious binder, to measure their electrical resistivity values and to determine the maximum beneficial fiber content required to attain electrical percolation. Experimental observations suggest that CFR-geopolymer cement exhibits superior performance to CFR-OPC in terms of conducting electrical current.

• Proceedings of the KIEE Conference
• /
• 2003.07c
• /
• pp.1837-1839
• /
• 2003

Recently deep interests have been paid on the effective generation of ozone, which has been widely used for water treatment, deoderization, color removal and chemical processing of exhausted smoke. The silent discharge reaction has been proposed as the most effective in the many ozone generation methods by electric discharge, because silent discharge excel others in the condition of high ozone generation yield and low power consumption. In this paper, ozone water generated system measure with silent discharge characteristics and pulsed power supply.

• Proceedings of the KIEE Conference
• /
• 2003.07c
• /
• pp.1843-1844
• /
• 2003

154 kV급 가스절연개폐장치(GIS)용dp 장착할 수 있는 내장형 극초단파 (UHF) 부분방전(PD) 센서의 고주파 특성을 전산모사 하였다. UHF PD 센서는 일종의 광대역 안테나이므로 3차원 전자기장 해석도구를 활용하여 주파수 또는 시간 영역에서 고주파특성을 해석하였다. 센서의 구조를 결정하는 센서장착용 구멍과 센서의 크기를 변수로 조절하면서 내장형 UHF PD 센서의 특성을 해석 하였다. 센서가 장착되는 구멍의 크기와 센서의 구조변화에 따라 반사손실이 변화하였으며 GIS의 전파 mode의 영향을 받는다.

• Proceedings of the KIEE Conference
• /
• 1996.11a
• /
• pp.323-325
• /
• 1996

The design of Intelligent Energy Saving Power System Controller (IESPSC) for Telecom DC power plants is proposed and presented in this paper. From the past experience. rectifiers for Telecom DC power plants have been operated inefficiently at light loads. IESPSC offers "novel load sharing" approach based on the knowledge of each unit's efficiency of paralleled rectifiers. Neural networks is used for identifying each rectifier's efficiency characteristic curve corresponding to load currents, which is in turn utilized to produce a system efficiency close to the maximum under all operating conditions. In addition, by limiting the number of operating units to the minimum while maintaining high efficiency at the determined loads, a drastic savings in operating cost can be achieved.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09a
• /
• pp.377-378
• /
• 2006

Thermal management technology is a critical element in all new chip generations, caused by a power multiplication combined with a size reduction. A heat sink, mounted on a base plate, requires the use of special materials possessing both high thermal conductivity (TC) and a coefficient of thermal expansion (CTE) that matches semiconductor materials as well as certain packaging ceramics. In this study, nano tungsten coated copper powder has been developed with a wide range of compositions, 90W-10Cu to 10W-90Cu. Powder technologies were used to make samples to evaluate density, TC, and CTE. Measured TC lies among theoretical values predicted by several existing models.

• 한국약용작물학회:학술대회논문집
• /
• 2012.05a
• /
• pp.271-272
• /
• 2012

• Journal of the Korean Magnetics Society
• /
• v.5 no.5
• /
• pp.631-635
• /
• 1995

Longitudinal magnetic recording process of thin film media was simulated by the 2-D finite element method (FEM). To describe precisely the hysteresis behavior of thin film media, scalar Preisach model was used. In this paper, we discussed the formation of bit patterns and importance of modeling of minor loops in high density recording. The effects of the media coercivity and film thickness on the remanent magnetization and transition shape were investigated.

• Review of KIISC
• /
• v.31 no.3
• /
• pp.7-12
• /
• 2021

사이버 공간은 제4차 산업혁명의 진전과 5세대 이동통신(5G) 시대의 도래로 초연결사회의 핵심요소로 등장하였다. 하지만 이러한 사이버공간 활용성의 증대와 함께 취약성도 증대하고 있어 사이버상의 산업기술 유출 역시 증가할 전망이다. 실제로 국내외에서 중소기업, 대기업을 막론하고 다양한 사이버공격을 통한 산업기술 유출 사례가 속속 보고되고 있다. 특히, 과거 No Tech상의 사이버공격에서 APT, 다크웹, 클라우드 서비스 등 High Tech를 이용하는 고도화된 사이버공격으로 진화하고 있다. 이는 기업의 영업비밀 유출 노하우 손실, 일자리와 경쟁우위 손실 등 경제력 손실과 평판 하락에 큰 영향을 미친다. 이에 본 논문에서는 국내외 사이버공격을 통한 산업기술 유출사고의 영향력을 산정하고 이에 대한 시사점을 서술 한다.

• Journal of Fashion Business
• /
• v.26 no.6
• /
• pp.116-132
• /
• 2022

Fashion marketing activity performed by social media influencers (SMIs) has grown exponentially in the past years. Research regarding their marketing power is often discussed in the context of sponsorship disclosure, in order to overcome obstacles of impending regulations that may endanger the authenticity SMIs are perceived to have compared to traditional marketing agents. Upon recent heterogeneous findings, a netnographic approach was taken to examine the actual sponsored posts of SMIs on Instagram. Based on two representative cases that received media coverage, a qualitative analysis of 1,058 comments on Instagram showed customer inspiration and informational social influence regardless of sponsorship disclosures present. Regarding customer inspiration, high frequency of comments including choice imitation intentions was observed. Under certain conditions, customer responses were focused on the SMI's expertise irrespective from the brand being endorsed. Findings show future implications from both an academic and industry-focused perspective for future potential of SMIs in fashion marketing.

• Progress in Superconductivity and Cryogenics
• /
• v.25 no.4
• /
• pp.40-44
• /
• 2023

For high-temperature superconducting power applications that need large current capacity, a large current conductor manufactured using multiple superconducting tape is required. Conductors being studied for large currents capacity such as CORC, TSTC, and RACC have advantages and disadvantages, and in order to use these conductors in coil form and apply them to AC power devices, research on magnetization loss occurring in superconductors due to external magnetic fields is essential. To accurately measure magnetization loss in a conductor that is twisted by stacking straight conductors like TSTC, the correlation between the measuring system and the shape of the sample must be clearly known to accurately measure the loss. In this paper, we will confirm the difference in magnetization loss measurement values according to the correlation between the length of the pickup coil and the twist pitch of the sample in CORC and TSTC shapes, and review considerations for accurate magnetization loss measurement from the results.