• Computers and Concrete
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• v.26 no.6
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• pp.497-504
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• 2020

Concrete can lose its alkalinity by concrete carbonation causing steel corrosion. Thus, the determination of the carbonation depth is necessary. An empirical model is proposed in this research to predict the carbonation depth of concrete using Gene expression programming (GEP). The GEP model was trained and validated using a large and reliable database collected from the literature. The model was developed using the six parameters that predominantly control the carbonation depth of concrete including carbon dioxide CO2 concentration, relative humidity, water-to-cement ratio, maximum aggregate size, aggregate to binder ratio and carbonation period. The model was statistically evaluated and then compared to the Jiang et al. model. A parametric study was finally performed to check the proposed GEP model's sensitivity to the selected input parameters.

• Journal of the Korean Society of Clothing and Textiles
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• v.45 no.2
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• pp.356-375
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• 2021

The Generation Z (Gen-Z) consumer has a unique beauty-consuming behavior that is distinct from the previous generations. This study aims to identify the meaning of makeup rituals based on the theoretical framework of the ritual concept. In-depth interviews were conducted with fifteen females in their mid-teens to early 20s. The results showed that Gen-Z has different types of makeup ritual scripts for both ordinary days and special days, which are constantly being re-written and revised based on the experience accumulated. In addition, there are various types of ritual artifacts that play an important role in Gen-Z's makeup ritual, and that they provide psychological comfort and satisfaction. The importance of DIY (Do It Yourself), collecting, and independent brands is emphasized. The role of Gen-Z in the makeup ritual was expanding from a creator for her own ritual to a collaborator for peers' rituals, and sometimes the expansion goes beyond the direct relationships to virtual ones through SNS (Social Network Service). The Gen-Z cohort is found to be a member of beauty knowledge network through which they learn, share, and create the know-how and shopping skills.

• Journal of Environmental Impact Assessment
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• v.20 no.2
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• pp.207-215
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• 2011

In order to establish fundamental data for stream restoration and environmental flow, we investigated physical habitat conditions of Korean chub (Zacco koreanus) in the typical streams of Han River. Field monitoring including fish sampling was conducted from September 2008 to April 2010. A total number of fish caught in the 8 sites was 3,421 representing 8 families 31 species, and 17 species (54.8%) including Korean shinner (Coreoleuciscus splendidus) and Z. koreanus were Korean endemic species during the study period. The most frequently found species in number was pale chub (Z. platypus, 25.7%) followed by Z. koreanus (22.8%) and Microphysogobio longidorsalis (16.8%). Numbers of Z. Koreanus ranged from 8 to 10 cm of total length were the highest in size distribution of their population in all sites. They were widely found in ranges of flow velocity (0.2~0.9 m/sec, 89.6%), water depth (0.3~0.9 m, 91.6%), and different types of substrates except for silt, and they tended to prefer run (58.1%) and riffle (33.7%) with cobble bed (47.0%) microhabitat. Most of upper streams in Korea consist of riffles and runs that are repeatedly followed by another one. However, stream channelization and leveling have caused reduction of habitat diversity. Therefore, it is necessary to make an effort on stream rehabilitation with evaluation of physical habitat condition by indicator species in order to maintain biodiversity and perform ecological restoration.

• Journal of the Korean Geotechnical Society
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• v.18 no.3
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• pp.43-50
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• 2002

This paper describes a simplified numerical procedure for analyzing the response of bridge pier foundations due to riverbed scouring. A computationally efficient algorithm to analyze the behavior of a pile group is proposed by considering soil-pile, pile-cap, and pile-fluid interactions. The complex phenomenon of the pile-soil interaction is modeled by discrete nonlinear soil springs (p-y, t-z and q-z curves). The pile-cap interaction is considered by geometric configuration of the piles in a group and connectivity conditions between piles and the cap. The pile-fluid interaction is incorporated into the procedure by reducing the stiffness of the soil-pile reactions as a result of nonlinearity and degradation of the soil stiffness with river bridge scouring. Through the numerical study, it is shown that the maximum bending moment increases with increasing scour depth. Thus it is desirable to check the stability elf pile groups based on soil-pile and pile-cap interactions by considering scouring depth in the riverbed.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.69.1-69.1
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• 2013

We describe a survey of quasars in the early universe beyond z=5, which is one of the main sciences of the Infrared Medium-deep Survey (IMS) performed by the Center for the Exploration of the Origin of the Universe (CEOU). We use multi-wavelength archival data such as SDSS, CFHTLS, UKIDSS, and SWIRE, which provide deep images over wide areas sufficient enough for searching high redshift quasars. In addition, we carried out a J-band imaging survey at the United Kingdom InfraRed Telescope (UKIRT) with a depth of ~23 AB and survey area of ~100 $deg^2$, which makes IMS the most suitable survey for finding high redshift quasars at z~7. Also for the quasar candidates at z~5.5, we are conducting observations with the Camera for QUasars in EArly uNiverse (CQUEAN), which are efficient for selecting robust quasar candidate samples in this redshift range. We used various color-color diagrams suitable to the specific redshift ranges, which can reduce the contaminating sources such as M/L/T dwarfs, low redshift galaxies, and instrumental defects. The high redshift quasars we are confirming can provide us with clues to the growth of super massive black holes since z~7. Also by expanding the quasar sample at 5

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.5
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• pp.509-517
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• 2009

Seagrass meadows are important biogenic habitats for a wide variety of marine animals and plants, a source of organic carbon for commercially important animals, and act as a nutrient filter in estuarine and coastal ecosystems. As such, mapping the distribution of seagrass beds provides us with an important component of management and conservation strategies. To survey seagrass distribution within Deukryang Bay, we directly observed seagrass beds using SCUBA in Boseong-gun, Goheung-gun, and Jangheung-gun. Seagrass distribution in Geogeum and Gumdang islands were not observed. Specifically, we monitored the distribution area, species composition, morphology, density, and biomass of seagrass meadows. Seagarss beds were mapped for Daikum-ri coast, Deukryang island, Yongjeong-ri coast, Samsan-ri coast and Ongam-ri coast. Total seagrass coverage in Deukryang Bay was $5.1\;km^2$, $4.8\;km^2$ of which was Zostera marina, $0.3\;km^2$ Z. caulescence and $0.01\;km^2$ Z. japonica. Z. japonica was found in intertidal zones, Z. marina was found from the intertidal to subtidal zones of 2 m MSL (mean sea level) depth, and Z. caulescence was found in subtidal zones of 2.5-5 m MSL.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.8
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• pp.30-38
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• 2003

High-speed machining is one of the most effective technology to enhance productivity especially for hardened die material. High-speed machining can give great advantages for machining of dies and molds. But selection of machining condition is very difficult because of complicated machining mechanism. This paper presents the selection of machining condition in high-speed machining of STD11. Depth of cut, feed rate and spindle revolution are control factors. The effect of the control factors on surface roughness and machining error in Z-direction is discussed to improve machining accuracy.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.72.2-72.2
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• 2021

Cosmic reionization imprints its history on the sky map of the cosmic microwave background (CMB) polarization. Even though mild, the signature of the reionization history during its early phase (z>15) can also impact the CMB polarization. We forecast the observational capability of the LiteBIRD(Lite(Light) satellite for the studies of B-mode polarization and Inflation from cosmic background Radiation Detection), a truly cosmic-variance limited apparatus. We focus on the capability for such an apparatus to probe the partial optical depth of the CMB photons during z>15. We show that LiteBIRD is able to probe this quantity with a modest to high significance, enabling one to tell how efficient the cosmic reionization and star formation were at z>15.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.35-60
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• 1997

Physical properties of composite resins such as strength, resistance to wear, discoloration, etc, depend on the degree of conversion of the resin components. The clinical behavior of restorative resins varies brand to brand. Part of this variation is associated with the filler and differences in the polymer matrix. The polymer matrix of resins may differ because the involved monomers are dissimilar and because of variation in the catalyst system. The purpose of this study was to evaluate the degree of conversion of the composite resins according to the depth of cure and light curing time. 7mm diameter cylindrical aluminum molds were filled with each of five different hybrid light curing composite resins(Z-100, Charisma, Herculite XRV, Prisma TPH, Veridonfil) on the thin resin films. The molds were 1mm, 2mm, 3mm, 4mm, and 5mm in depth to produce resin films of various heights. Each sample was given 20sec, 40sec, and 60sec illumination with a light source. The degree of conversion of carbon double bonds to single bonds in the resin films was examined by means of Fourier Transform Infrared Spectrometer. The results were obtained as follows; 1. There was difference in the degree of conversion among five light curing composite resins according to the depth of cure for 20sec, 40sec, and 60sec illumination with light source with statistical significance(P<0.05). 2. Five light curing composite resins show lower degree of conversion at surface of the resin than depth of 1mm. 3. The degree of conversion of five light curing composite resins was siginificantly reduced from the maximum for the resin film when the light passed through as little as 1mm of each composite. 4. The degree of conversion of five light curing composite resins decrease significantly at the depth of 4mm, and polymerization was not occured at the depth of 5mm except for Prisma TPH. 5. The degree of conversion of five light curing composite resins was increased with increased light curing time, and there was no significant differences in the degree of conversion above 4mm in Z-100, 3mm in Charisma, and at depth of 5mm in Herculite XRV and Veridonfil(P>0.05).

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.7
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• pp.53-61
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• 1998

In this paper, we propose an efficient multi-view images coding algorithm to find the optimal depth and texture from the set of multi-view images. The proposed algorithm consists of two consecutive steps, i) the depth estraction step, and ii) the texture extraction step, comparedwith the traditional algorithem which finds the depth and texture concurrently. The X-Y plane of the normalized object space is divided into traingular paatches and the Z value of the node is determined in the first step and then the texture of the each patch is extracted in the second step. In the depth extraction step, the depth of the node is determined by applying the block based disparity compensation method to the windowed area centered at the node. In the second step, the texture of the traingular patches is extracted from the multi-view images by applying the affine transformation based disparity compensation method to the traingular pateches with the depth extracted from the first step. Experimental results show that the SNR(Singnal-to- Noise Ratio) of images enconded by our algorithm is better than that of images encoded by the traditional algorithm by the amount about 4dB for for the test sets of multi-view images called dragon, kid, city and santa.