Influence of Different Foreign Emissions Inventories on Simulated, Ground-Level Ozone in the Seoul Metropolitan Area during May 2014

Kim, Byeong-Uk,You, Seunghee,Kim, Hyun Cheol,Lim, Yongjae,Suh, Insuk,Lee, Jae-Bum,Woo, Jung-Hun,Kim, Soontae Taiwan Association for Aerosol Research 2017 Aerosol and air quality research Vol.17 No.12

Interference Alignment with Receive Antenna Partitioning for SWIPT-Enabled Fog RANs

Yongjae Kim,Janghyuk Youn,정방철 한국통신학회 2022 ICT Express Vol.8 No.4

We propose a novel interference alignment (IA) technique with receive antenna partitioning (RAP) for simultaneous wireless information and power transfer (SWIPT)-enabled downlink fog radio access networks (F-RANs). The basic idea of the proposed scheme is to apply a generalized downlink IA for each access point (AP) and to divide receive antennas at each user into two groups for information decoding (ID) and energy harvesting (EH), respectively. With the proposed scheme, an optimal receive antenna configuration at each user is obtained to maximize the weighted sum of achievable rate and the sum of harvested energy of the network. Also we develop an antenna configuration selection algorithm to obtain near-optimal performance with low computational complexity. Through extensive computer simulations, it is shown that the proposed scheme significantly improves a rate-energy region compared with existing techniques.

Activator-specific requirements of distinct Mediator proteins

Kim, Taewhan,Kim, Jeongmo,Kwon, Yongjae,Kim, Young-Joon 이화여자대학교 세포신호전달연구센터 2004 고사리 세포신호전달 심포지움 Vol. No.6

Living cells cope with diverse physiological and environmental changes by reprogramming the pattern of gene expression to mount an appropriate biological response. Although distinct sequence-specific transcription factors that bind to particular regulatory elements and enhancers are primarily responsible for this regulation, transcriptional coactivator-corepiessor proteins that allow these factors to transmit signals that affect both chromatin structure and the transcription machinery also add a significant secondary layer to the regulation of gene expression. A number of coactivator complexes have been identified in eukaryotes, and their functions in gene activation at specific promoters have been analyzed, primarily in vitro. However, the mechanism by which these transcriptional coactivators regulate gene expression in living organisms is not well understood. We isolated the Drosophila Mediator complex and showed that it is critical for transcriptional activation in response to diverse activator proteins in vitro. More importantly, we found that Mediator mutant flies exhibit transcriptional defects for a wide range of developmentally regulated genes, validating the requirement for Mediator in gene transcription in vivo. In addition, for transcription of the Drosophila heat shock genes, Mediator is recruited to the promoter region by heat shock transcription factor(HSF) under heat shock conditions. This indicates that Mediator is the primary in vivo activator target that relays regulatory signals from enhancer-bound activators to the basal transcription machinery. However, it is necessary to explore this idea further by examining the interaction of Mediator with many other activator proteins before we accept any generalized view of the mechanism by which Mediator regulates Pol Ⅱ transcription. For this, we tested a number of natural transcriptional activator proteins for their ability to interact with Mediator proteins in vitro. When twenty-five components were tested, these activators required different components for activation each other. Hence each activator appears to depend on distinct binding targets for Mediator recruitment and transcriptional activation. These findings will aid us in our understanding of the mechanisms by which gene-specific cofactors are recruited to promoters for selective transcriptional activation in higher eukaryotes.

Nonsaturated Throughput Analysis of Coexistence of Wi-Fi and Cellular With Listen-Before-Talk in Unlicensed Spectrum

Kim, Yongjae,Song, Yujae,Choi, Yonghoon,Han, Youngnam IEEE 2017 IEEE Transactions on Vehicular Technology VT Vol.66 No.12

<P>This paper analyzes the coexistence performance of Wi-Fi and cellular networks conditioned on nonsaturated traffic in the unlicensed spectrum. Under the condition, the time-domain behavior of a cellular small-cell base station (SCBS) with a listen-before-talk (LBT) procedure is modeled as a Markov chain, and it is combined with a Markov chain which describes the time-domain behavior of a Wi-Fi access point. Using the proposed model, this study finds the optimal contention window size of cellular SCBSs in which total throughput of both networks is maximized while satisfying the required throughput of each network, under the given traffic densities of both networks. This will serve as a guideline for cellular operators with respect to performing LBT at cellular SCBSs according to the changes of traffic volumes of both networks over time.</P>

Evening Scent

Yongjae KIM 한국색채학회 2014 International Invitation Exhibition of Color Works Vol.2014 No.-

Effect of steel fiber volume fraction and aspect ratio type on the mechanical properties of SIFCON-based HPFRCC

Kim, Seugnwon,Jung, Haekook,Kim, Yongjae,Park, Cheolwoo Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.65 No.2

Plain concrete is a brittle material with a very low tensile strength compared to compressive strength and critical tensile strain. This study analyzed the dynamic characteristics of high-performance fiber-reinforced cementitious composites based on slurry-infiltrated fiber concrete (SIFCON-based HPFRCC), which maximizes the steel-fiber volume fraction and uses high-strength mortar to increase resistance to loads, such as explosion and impact, with a very short acting time. For major experimental variables, three levels of fiber aspect ratio and five levels of fiber volume fraction between 6.0% and 8.0% were considered, and the flexural strength and toughness characteristics were analyzed according to these variables. Furthermore, three levels of the aspect ratio of used steel fibers were considered. The highest flexural strength of 65.0 MPa was shown at the fiber aspect ratio of 80 and the fiber volume fraction of 7.0%, and the flexural strength and toughness increased proportionally to the fiber volume fraction. The test results according to fiber aspect ratio and fiber volume fraction revealed that after the initial crack, the load of the SIFCON-based HPFRCC continuously increased because of the high fiber volume fraction. In addition, sufficient residual strength was achieved after the maximum strength; this achievement will bring about positive effects on the brittle fracture of structures when an unexpected load, such as explosion or impact, is applied.

Properties enhancement of recycled aggregate concrete through pretreatment of coarse aggregates – Comparative assessment of assorted techniques

Kim, Yongjae,Hanif, Asad,Kazmi, Syed M.S.,Munir, Muhammad J.,Park, Cheolwoo Elsevier 2018 JOURNAL OF CLEANER PRODUCTION Vol.191 No.-

<P><B>Abstract</B></P> <P>In this study, the intrinsic properties of recycled coarse aggregates (RC), associated with bonded mortar, were modified with two different pretreatment techniques viz-a-viz HCl pretreatment and Na<SUB>2</SUB>SO<SUB>4</SUB> pretreatment, while maintaining a fixed aggregate-to-solution ratio of 1:4.5. The residual bonded mortar was quantified to evaluate the potential of both techniques. HCl pretreatment yielded greater removal of bonded mortar content (BMC), almost twice as high as achieved by Na<SUB>2</SUB>SO<SUB>4</SUB> pretreatment. Subsequently, the concretes were developed (termed as recycled aggregate concrete; RAC) by incorporating HCl treated coarse aggregates (HTC) and Na<SUB>2</SUB>SO<SUB>4</SUB> treated coarse aggregates (STC). Both natural and recycled (untreated) fine aggregates (NF and RF, respectively) were used. Control specimens with natural coarse aggregates (NC) were prepared for comparative assessment. The resulting properties showed significantly influenced by bonded mortar content (BMC). About 14% higher compressive strength was achieved by using HTC in comparison with untreated RC, while a mere corresponding decline of 5% was seen when compared with NC. Likewise, the carbonation resistance and the resistance to chloride ion penetration showed better performance for HTC and STC incorporated concretes. Such superior performance is attributed to the denser interface (between the aggregate and paste matrix) with reduced pores/voids, as assessed from the optical and scanning electron microscopy. Further, the determined properties were used to develop regression models for the prediction of RAC properties. The prediction equations thus obtained showed remarked precision with the experimentally determined results, and as such these can be used for strength and durability prediction.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Properties of recycled coarse aggregates (RC) were improved by pre-treating with HCl and Na<SUB>2</SUB>SO<SUB>4</SUB>. </LI> <LI> HCl pretreatment was demonstrated twice as beneficial as Na<SUB>2</SUB>SO<SUB>4</SUB> pretreatment. </LI> <LI> Concretes incorporating treated RC showed remarkable properties enhancement. </LI> <LI> Recycled aggregate concrete properties were also modeled (by regression) based on bonded mortar content. </LI> </UL> </P>

The Midnight Friend

YongJae KIM 한국색채학회 2015 International Invitation Exhibition of Color Works Vol.2015 No.-

Impact of Core and Peripheral Service Satisfaction on Team Identification and Revisit Intention: A Comparison of Minor and Major League Ice Hockey

Yongjae Kim,Elizabeth Rogol,Joon Sung Lee 글로벌지식마케팅경영학회 2022 Journal of Global Sport Management Vol.7 No.1

By incorporating two different types of service satisfaction (core and peripheral service), this study developed and tested a con- ceptual model delineating the impact of consumers’ satisfaction on fans’ team identification and revisit intent and examined the differential patterns among the variables across different sport league levels. Data were collected from a total of 918 spectators of both major and minor league ice hockey events. This study showed that the impact of core and peripheral service-related satisfaction varies across the sport contexts. The results provided empirical evidence of the direct effect of core service-related satis- faction on team identification leading to revisit intent in both major and minor league sport contexts, while peripheral service- related satisfaction had a direct effect on team identification in only the major league sport context. Direct effect of peripheral service-related satisfaction on revisit intent was evident in the minor league sport context but not in the major league sport context.

Hydrogen-Bond-Assisted Controlled C–H Functionalization via Adaptive Recognition of a Purine Directing Group

Kim, Hyun Jin,Ajitha, Manjaly J.,Lee, Yongjae,Ryu, Jaeyune,Kim, Jin,Lee, Yunho,Jung, Yousung,Chang, Sukbok American Chemical Society 2014 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.136 No.3

<P>We have developed the Rh-catalyzed selective C–H functionalization of 6-arylpurines, in which the purine moiety directs the C–H bond activation of the aryl pendant. While the first C–H amination proceeds via the N1-chelation assistance, the subsequent second C–H bond activation takes advantage of an intramolecular hydrogen-bonding interaction between the initially formed amino group and one nitrogen atom, either N1 or N7, of the purinyl part. Isolation of a rhodacycle intermediate and the substrate variation studies suggest that N1 is the main active site for the C–H functionalization of both the first and second amination in 6-arylpurines, while N7 plays an essential role in controlling the degree of functionalization serving as an intramolecular hydrogen-bonding site in the second amination process. This pseudo-Curtin–Hammett situation was supported by density functional calculations, which suggest that the intramolecular hydrogen-bonding capability helps second amination by reducing the steric repulsion between the first installed ArNH and the directing group.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2014/jacsat.2014.136.issue-3/ja4118472/production/images/medium/ja-2013-118472_0019.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja4118472'>ACS Electronic Supporting Info</A></P>