SNS as an Online Shopping Platform : A Cognitive Load Perspective

Jaecheol Park,Garam Hong,Hyunjin Do 한국경영정보학회 2017 한국경영정보학회 학술대회논문집 Vol.2017 No.12

Social commerce — online shopping through social media — is well-known as a new style of consumption because shoppers now use not only websites but also Facebook, Instagram, and other forms of SNS. We investigated (1) the factors that affect purchase intension in social commerce and (2) the moderating effect of type of SNS platforms. Two methods — interviews and surveys — were used to differentiate the relationships among variables from 150 Facebook and Instagram users in Korea. First, we found that seller-related variables such as selfdisclosure, intimacy, expertise, and attractiveness are related to trust; platform-related variables such as customization and simplicity are related to convenience. In turn, trust and convenience are related to purchase intention in social commerce. Second, we found that types of SNS platforms moderate the relationships between platform-related variables and convenience. These findings contribute to the literature and provide guidelines that have managerial implications for both sellers and platform managers.

A Return-to-zero DAC with Tri-state Switching Scheme for Multiple Nyquist Operations

Jaecheol Yun,Yun-Hwan Jung,Taegeun Yoo,Yohan Hong,Ju Eon Kim,Dong-Hyun Yoon,Sung-Min Lee,Youngkwon Jo,Yong Sin Kim,Kwang-Hyun Baek 대한전자공학회 2017 Journal of semiconductor technology and science Vol.17 No.3

A return-to-zero (RZ) digital-to-analog converter (DAC) with a tri-state switching scheme is proposed in this paper. The proposed scheme provides a triple weight output for RZ operation by using a conventional differential current switch and simple pseudo-differential F/Fs. The RZ function is realized with only two additional transistors in each F/F cell, which results in a power dissipation increase of less than 5%. To verify the performance of the proposed method, a 10-bit RZ DAC is fabricated using standard 180-㎚ CMOS technology. Measured results show that the worst SFDR performances are 60 ㏈c and 55 ㏈c in the 1st and 2nd Nyquist bands, respectively, when operating at 650 ㎒ clock frequency. The total power consumption is 64 ㎽, and the active area occupies 0.25 ㎟.

In vitro modeling for inherited neurological diseases using induced pluripotent stem cells: from 2D to organoid

Ki Hong Nam,Sang Ah Yi,Hyun Ji Jang,Jeung‑Whan Han,Jaecheol Lee 대한약학회 2020 Archives of Pharmacal Research Vol.43 No.9

Stem cells are characterized by self-renewal andby their ability to differentiate into cells of various organs. With massive progress in 2D and 3D cell culture techniques,in vitro generation of various types of such organoids frompatient-derived stem cells is now possible. As in vitro differentiationprotocols are usually made to resemble humandevelopmental processes, organogenesis of patient-derivedstem cells can provide key information regarding a rangeof developmental diseases. Human stem cell-based in vitromodeling as opposed to using animal models can particularlybenefit the evaluation of neurological diseases becauseof significant differences in structure and developmental processesbetween the human and the animal brain. This reviewfocuses on stem cell-based in vitro modeling of neurodevelopmentaldisorders, more specifically, the fundamentalsand technical advancements in monolayer neuron and brainorganoid cultures. Furthermore, we discuss the drawbacks ofthe conventional culture method and explore the advanced,cutting edge 3D organoid models for several neurodevelopmentaldiseases, including genetic diseases such as Downsyndrome, Rett syndrome, and Miller–Dieker syndrome, aswell as brain malformations like macrocephaly and microcephaly. Finally, we discuss the limitations of the currentorganoid techniques and some potential solutions that pave the way for accurate modeling of neurological disorders ina dish.

Flexible 박막 Si태양전지 응용을 위한 SUS기판 위의 AZO-Ag 이중구조 배면전극의 전기/구조적 특성

홍창우(Hong, ChangWoo),최용성(Choi, YoungSung),박재철(Park, Jaecheol),이종호(Lee, JongHo),김태원(Kim, TaeWon) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.05

빛 에너지를 전기에너지로 변환하는 발전소자인 태양전지는 청정 재생 에너지원으로 최근 Si 박막 태양전지의 고 효율화를 위해 여러 기술적인 면에서 개발되어지고 있다. 현재 박막형 태양전지는 실리콘계가 주류를 이루고 있으며, 유리 혹은 유연성기판(금속 or 고분자)에 비정질 실리콘 박막을 형성시킨 태양전지와 실리콘웨이퍼의 양면에 태양전지를 형성함으로써 효율을 극대화시킨 이종접합태양전지 등이 연구되고 있다. 특히 flexible 태양전지는 hard 기판에 비해 비교적 저가인 플라스틱 필름과 금속 foil을 기판으로 이용함으로서 저가화가 용이하며, 가볍고 유연성을 갖추고 있어 휴대와 시공에 있어 매우 우수한 장점을 가지고 있다. 본 연구에서는 flexible 기판(stainless steel)을 이용하여 태양전지 내 반사막 층이 미치는 영향을 알아보기 위하여 AZO/Ag 이중구조 박막의 특성을 연구하였다. RF magnetron sputtering system을 이용하였으며, 상온에서 Ag/AZO 이중구조 박막을 제조하였다. stainless steel 기판 위에 Ag층을 25nm 두께로 증착하였으며 연속공정으로 AZO 박막을 100~500nm의 두께경사를 가지도록 성장시켰다. 이 때의 AZO/Ag 이중구조 박막의 표면 morphology는 AFM 분석결과 7nm~3nm의 값을 나타내었으며, AZO 박막의 두께가 증가할수록 rms 값이 감소하는 경향을 보여주었다. 본 발표에서는 flexible 기판 상에 성장된 AZO/Ag 이중구조 박막의 전기적, 광학적 특성 등에 관하여 추가적으로 토론한 후 태양전지 효율 중 흡수층 내 반사막 층이 미치는 역할을 알아보겠다.

공간적 위계를 고려한 2차 디자인 서울거리 조성 사업의 효과 분석 연구

홍진기(Hong, Jin-Ki),김재철(Kim, Jaecheol) 한국도시설계학회 2019 도시설계 : 한국도시설계학회지 Vol.20 No.3

이 연구의 목적은 사례연구를 통하여 가로환경개선사업의 입지 특성과 사업 효과 간의 관계를 규명하는 것이다. 2차 디자인서울거리사업을 사례로 하였으며, 여러 입지 특성 중 특히 공간위계에 초점을 맞춰 사업 대상지들을 ‘지역중심’과 ‘근린중심’으로 분류하고, 두 그룹의 사업효과를 심리적 및 실질적 두 가지 측면에서 비교 분석하였다. 분석 결과, 먼저 심리적 효과 측면은 ‘지역중심’에서는 상권 활성화 정도가, ‘근린중심’에서는 경관 · 이미지, 교통안전의 개선정도가 전반적 만족도에 더 많은 상관관계를 가지는 것으로 나타났으며, 실질적 효과 측면은 ‘지역중심’에서는 공시지가 상승이, ‘근린중심’에서는 교통사고 감소가 분명하게 나타난 반면, 모든 연구대상지에서 유동인구 증가는 나타나지 않았다. The purpose of this study is to identify the relationship between the locational characteristics of the street environmental improvement projects and the project effectiveness. For this purpose, multiple case studies were conducted and the Second Design Seoul Street projects were taken as the cases. Particularly focusing on spatial hierarchy among the locational characteristics, the case areas were classified into regional and neighborhood centers, and the effects of the two groups were analyzed in terms of both psychological and practical aspects. The results showed that, regarding psychological effects, the degree of commercial vitalization was more correlated with the overall satisfaction level in the regional centers, while the degree of improvement in landscape and traffic safety was more correlated with the overall satisfaction in the neighborhood centers. Regarding practical effects, there was decrease of traffic accidents in the neighborhood centers and increase of the official land price in the regional centers. However, the increase of the pedestrian traffic volume did not appear in all study sites.

서울 단독주택지역에서의 근린상점 이용행태와 영역의식에 관한 연구

홍영화(Hong, Young Wha),김재철(Kim, Jaecheol) 대한국토·도시계획학회 2014 國土計劃 Vol.49 No.7

A Return-to-zero DAC with Tri-state Switching Scheme for Multiple Nyquist Operations

Yun, Jaecheol,Jung, Yun-Hwan,Yoo, Taegeun,Hong, Yohan,Kim, Ju Eon,Yoon, Dong-Hyun,Lee, Sung-Min,Jo, Youngkwon,Kim, Yong Sin,Baek, Kwang-Hyun The Institute of Electronics and Information Engin 2017 Journal of semiconductor technology and science Vol.17 No.3

A return-to-zero (RZ) digital-to-analog converter (DAC) with a tri-state switching scheme is proposed in this paper. The proposed scheme provides a triple weight output for RZ operation by using a conventional differential current switch and simple pseudo-differential F/Fs. The RZ function is realized with only two additional transistors in each F/F cell, which results in a power dissipation increase of less than 5%. To verify the performance of the proposed method, a 10-bit RZ DAC is fabricated using standard 180-nm CMOS technology. Measured results show that the worst SFDR performances are 60 dBc and 55 dBc in the 1st and 2nd Nyquist bands, respectively, when operating at 650 MHz clock frequency. The total power consumption is 64 mW, and the active area occupies $0.25mm^2$.

이더리움 블록체인 성능 향상을 위한 기술 동향

홍상원(Sangwon Hong),신재철(Jaecheol Shin),이상준(Sangjun Lee) 한국정보과학회 2018 한국정보과학회 학술발표논문집 Vol.2018 No.6

Eudesmin impairs adipogenic differentiation via inhibition of S6K1 signaling pathway

Nam, Ki Hong,Yi, Sang Ah,Lee, Jaecheol,Lee, Min Gyu,Park, Jee Hun,Oh, Hwamok,Lee, Jieun,Park, Jong Woo,Han, Jeung-Whan Elsevier 2018 Biochemical and biophysical research communication Vol.505 No.4

<P><B>Abstract</B></P> <P>Eudesmin has been reported to possess diverse therapeutic effects, including anti-tumor, anti-inflammatory, and anti-bacterial activities. However, its molecular action has not been implicated in metabolic disease. In this study, we show that treatment of mesenchymal stem cells (MSCs) with eudesmin disturbs adipogenesis via suppression of S6K1 signaling pathway. Eudesmin treatment inhibited activation and nuclear translocation of S6K1. Consequently, S6K1-mediated phosphorylation of H2B at serine 36 (H2BS36p) was reduced upon eudesmin treatment, further inducing the expression of <I>Wnt6</I>, <I>Wnt10a</I>, and <I>Wnt1</I>0b, which disturbed adipogenic differentiation. Moreover, eudesmin promoted myogenic and osteogenic gene expression in MSCs. Taken together, we found a novel small molecule, eudesmin, to block adipogenesis through down-regulation of S6K1-H2BS36p axis, followed by regulation of cell fate determination genes. This study suggests a promising therapeutic approach with eudesmin to cure obesity and metabolic diseases.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Eudesmin inhibits activation sand nuclear translocation of S6K1. </LI> <LI> Eudesmin promotes <I>Wnt</I> gene expression by reducing S6K1-mediated H2BS36 phosphorylation. </LI> <LI> Eudesmin disturbs adipogenic gene expression and de novo adipocyte generation. </LI> <LI> Eudesmin enhances myogenic and osteogenic gene expression. </LI> </UL> </P>

박막 Si태양전지 응용을 위한 유리기판 위의 AZO-Ag 이중구조 배면전극의 전기광학적 특성

박재철(Park, Jaecheol),홍창우(Hong, ChangWoo),최용성(Choi, YoungSung),이종호(Lee, JongHo),김태원(Kim, TaeWon) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.05

현재 박막형 태양전지는 실리콘계가 주류를 이루고 있으며, 유리기판 또는 유연성 기판에 비정질 실리콘 박막을 형성시킨 태양전지와 실리콘 기판 양면에 태양전지를 형성하는 방법 등 효율을 극대화시킨 이종접합 태양전지 등이 연구되고 있다. 예컨대 밴드갭이 서로 다른 박막들 간의 이종접합을 이용한 tandem 구조 및 triple 구조의 Si 박막 태양전지의 경우 13%대 변환효율을 나타낸다고 보고된 바 있다. 본 연구에서는 비정질 Si 박막 태양전지 내 흡수층의 효율을 최대화하기 위하여 AZO/Ag 이중구조 박막의 특성에 관한 연구를 수행하고자 한다. combinatorial sputtering system을 이용하여 AZO/Ag 이중구조 박막을 제작하였으며 타겟으로는 4-inch target(Ag, 2wt% Al2O3 doped ZnO)이 사용되었다. 유리기판 상에 combinatorial sputter system으로 상온에서 제작된 Ag 박막의 두께는 25nm로 성장시켰으며 연속공정으로 AZO 박막을 제작하였고, AZO 박막은 100~500nm의 두께경사를 나타내었다. 이 때 유리기판상에 성장된 Ag/AZO 박막의 면저항은 약 2{Omega}/{Box} 값을 나타내었다. 본 발표에서는 AZO/Ag 이중 구조 박막의 우수한 전기적 특성을 기반으로 표면 거칠기 및 반사도 특성 등에 관하여 추가적으로 토론한다.