• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.34.2-35
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• 2018

Galaxy transition from star-forming to quiescent, accompanied with morphology transformation, is one of the key unresolved issues in extragalactic astronomy. Although several environmental mechanisms have been proposed, a deeper understanding of the impact of environment on galaxy transition still requires much exploration. My Ph.D. thesis focuses on which environmental mechanisms are primarily responsible for galaxy transition in different environments and looks at what happens during the transition phase using multi-wavelength photometric/spectroscopic data, from UV to mid-infrared (MIR), derived from several large surveys (GALEX, SDSS, and WISE) and our GMOS-North IFU observations. Our multi-wavelength approach provides new insights into the *late* stages of galaxy transition with a definition of the MIR green valley different from the optical green valley. I will present highlights from three areas in my thesis. First, through an in-depth study of environmental dependence of various properties of galaxies in a nearby supercluster A2199 (Lee et al. 2015), we found that the star formation of galaxies is quenched before the galaxies enter the MIR green valley, which is driven mainly by strangulation. Then, the morphological transformation from late- to early-type galaxies occurs in the MIR green valley. The main environmental mechanisms for the morphological transformation are galaxy-galaxy mergers and interactions that are likely to happen in high-density regions such as galaxy groups/clusters. After the transformation, early-type MIR green valley galaxies keep the memory of their last star formation for several Gyr until they move on to the next stage for completely quiescent galaxies. Second, compact groups (CGs) of galaxies are the most favorable environments for galaxy interactions. We studied MIR properties of galaxies in CGs and their environmental dependence (Lee et al. 2017), using a sample of 670 CGs identified using a friends-of-friends algorithms. We found that MIR [3.4]-[12] colors of CG galaxies are, on average, bluer than those of cluster galaxies. As CGs are located in denser regions, they tend to have larger early-type galaxy fractions and bluer MIR color galaxies. These trends can also be seen for neighboring galaxies around CGs. However, CG members always have larger early-type fractions and bluer MIR colors than their neighboring galaxies. These results suggest that galaxy evolution is faster in CGs than in other environments and that CGs are likely to be the best place for pre-processing. Third, post-starburst galaxies (PSBs) are an ideal laboratory to investigate the details of the transition phase. Their spectra reveal a phase of vigorous star formation activity, which is abruptly ended within the last 1 Gyr. Numerical simulations predict that the starburst, and thus the current A-type stellar population, should be localized within the galaxy's center (< kpc). Yet our GMOS IFU observations show otherwise; all five PSBs in our sample have Hdelta absorption line profiles that extend well beyond the central kpc. Most interestingly, we found a negative correlation between the Hdelta gradient slopes and the fractions of the stellar mass produced during the starburst, suggesting that stronger starbursts are more centrally-concentrated. I will discuss the results in relation with the origin of PSBs.

• Asian Journal of Turfgrass Science
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• v.1 no.1
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• pp.7-17
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• 1987

The experiment with two levels of nitrogen (0. and 300kg / ha / year) and two levels of clipping height (1.5cm and 4cm) was conducted on the field during the period 3 June to 23 October 1985. Clonal lines of korean lawngrass ( Zoysia japonica Steud.) and manilagrass ( Zoysia matrella ( L.) Merr.)of Daejon origin were established in June, as individual clone in rows 30cm apart with a 40cm spacing between clones, actually 4 clones each plot. The results obtained were as follows : 1. When no nitrogen was applied to korean lawngrass, leaf blade which appeared during the August / early September period remained green for a period of about 10 weeks and even leaves emerged in late September lived for 42 days. However, leaf longevity did not exceed 8 weeks as nitrogen was applied. In contrast the leaf longevity of manilagrass which emerged during the mid - August / early September period was 11 weeks and, under the nitrogen applied, 9 weeks, indicating that the life - saen of individual leaf of manilagrass may be longer than that of korean lawngrass. Meanwhile, clipping height had no effect on the leaf longevity in both grasses. 2. During the July / August period, tiller number, green leaf number and DM weight of korean lawngrass were increased significantly with fertilizer nitrogen, but were not with two levels of clipping height. This trend was reversed after late September : no effect of nitrogen was appeared. Instead, lax clipping increased tiller number, green leaf number and DM weight. Green leaves stimulated by lax clipping resulted in the occurrance of more dead leaves in late October. 3. The increase of tiller number, green leaf number, and DM weight of korean lawngrass due to nitrogen application appeared to be of significance in early September. Unlike korean lawngrass, however, this significant increase was maintained to late October when new green leaves still emerge. Clipping height had little effect on the growth of manilagrass by early September, but since then, lax clipping stimulated leaf appearance, possibly resulting in a remained green color of manilagrass turf. 4. Among the stolons outgrown until early September, the primary stolon was not influenced by nitrogen and clipping treatments to produce only 2 - 3 stolons. However, 1st branch stolon as affected by nitrogen increased significantly, so most of stolons which occurred consisted of 1st branch stolon. 5. Until early September, stolon length obtained at nil nitrogen level was chiefly caused by lengthening the primary stolons. By applying nitrogen the primary stolons of korean lawngrass was longer than 1st branch stolons when severe clipping was involved and in turn, shorter than 1st branch stolons when lax clipping was concerned. In manilagrass, 1st branch stolons were much longer than the primary stolons when turf was clipped severely but in conditions of lax clipping, there was little difference in length between primary and 1st branch stolons. 6. Stolon nodes of both korean lawngrass and manilagrass were positively influenced by nitrogen, but no particular increases by imposing clipping height treatment was marked in manilagrass. Although the stolon of korean lawngrass was grown until late october, the growth stimulated by nitrogen was not so remarkable as to exceed that a by nil N. 7. The thickness of korean lawngrass and manilagrass was greatest in late September, but that of manilagrass did not differ significantly from that in late October. 8. The response of stolon length of korean lawngrass to lax clippings was not so great in late October as to that to severe clippings. On the other hand, the positive effect of lax clippings to stolon length in m anilagrass was confirmed even in late October.

• Korean Journal of Ecology and Environment
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• v.34 no.2 s.94
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• pp.81-89
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• 2001

In order to know relationships between green euglenoids and environmental factors, the species composition and density were assessed for 12 months together with environmental variables in the Jeonjucheon urban drainage, Korea. Nitrate was a high of 3.22 mg/1 in June and phosphate concentration was over 0.71 mg/l in the winter. The euglenoids totaled 5 genera and 71 species throughout the year, increasing in the early summer (35 to 42 texa) and decreasing in the winter (below 20 taxa). The number of green euglenoids positively correlated with surface water temperature. the total density of the green euglenoids showed a typical bimodal pattern, being maximal in the winter (5,394 cells/ml in June). The winter peak was a result of active growths of Euglena caudata, E. geniculata and E. viridis, however, each of which positively correlated with the phosphate. The early summer peak was attributed to Euglena deses, Lepocinclis ovum, and Phacus trypanon, each of which positively correlated with the ammonium and nitrate. The complete bimodal spectrum of species number and density of green euglenoids provides a sensitive image in detecting the changes of environmental variables in polluted waters such as Jeonjucheon.

• Korean Journal of Organic Agriculture
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• v.23 no.2
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• pp.281-289
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• 2015

In sustainable viticulture, green manure represents a safe and non-polluting way to bring large quantities of organic matter into the soil. The cultivation of green manure crops plays an important role in soil quality and sustainability of agricultural system. This study was conducted to evaluate the effects of green manure fertilization on yield and quality of the Campbell Early grape variety in the organic vineyard. Hairy vetch was the more productive green manure crop, yielding higher dry materials. Average yields of grape were significantly greater in hairy vetch+rye ($13.02ton\;ha^{-1}$) than nature weed ($11.65ton\;ha^{-1}$), respectively. The concentrations of total as well as individual anthocyanins were consistently higher with hairy vetch treatment compared with rye and nature weed, thus making the green manure cultivation is an environmentally friendly cultivation to increase the yield and anthocyanin contents in organic grape.

• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.293-296
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• 2008

This study was carried to select artichoke (Cynara scolymus L.) varieties that can be cultivated in non-heated greenhouse during winter in Jeju Island in Korea. Artichoke varieties namely, 'Purple Romagna' (Neseed Co.), 'Imperial Star' (Keithley Williams Seed Co.), 'Green Globe' (Park Seed Co.), 'Emerald' (Ferry-morse Seed Co.), 'Italian' (Unknown), and 'Carciofo Di Romagna' (Lortolano), were raised in a plug tray with 72 cells for two months and transplanted in a non-heated greenhouse on October 5, 2004. The first harvesting of 'Emerald' and 'Imperial Star' were the earliest and April 26 and 27, 2005 respectively. Most of the varieties were harvested from early May to June 2005. The number of head per plant was the highest in 'Green Globe' with more than five heads and the lowest were recorded in 'Italian' with one head or less. The weight of heads per plant was more than 228 g in 'Purple Romagna', 'Imperial Star' and 'Green Globe'. The highest yield was in 'Green Globe' with 2,172 kg/10a, followed by 'Imperial Star' with 1,947 kg/10a. Accordingly, it is considered that 'Green Globe' and 'Imperial Star' are adequate for the high-yield cultivation in non-heated greenhouse in Jeju Island. They can be harvested from the April to June when cultivated from the early October of the previous year.

• Journal of Embryo Transfer
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• v.14 no.1
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• pp.1-8
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• 1999

The efficiency of transgenic livestock animal production may be improved by early selection of transgenci preimplantation embryos. To examine the possibility of GFP gene as a non-invasive marker for the early screening of transgenic embryo, the GFP gene was microinjected into rabbit zygotes and the later stages of preimplantation embryos were examined for the expression of GFP. The presence of injected DNA was detected by PCR analysis and the expression of GFP was detected by observing green fluorescence in embryos under a fluorescent microscope. Out of 108 GFP gene-injected rabbit zygotes, seventy three(67.6%) were fluorescence-positive. When 11 fluroresecence-positive blastocysts were analyzed for the presence of GFP gene by PCR, 6(54.5%) were positive, and all of the 8 flrouescence-negative blastocysts were also negative by PCR. The results indicate that the screening of transgene in rabbit embryos by PCR analysis and GFP detection could be a promising method for the preselection of transgenic embryos.

• Korean journal of applied entomology
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• v.50 no.2
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• pp.167-170
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• 2011

Pseudoips fagana Fabricius belongs to the subfamily Chloephorinae (Lepidoptera: Noctuidae). Eggs of Pseudoips fagana were white and oviposited on oak leaves. There were five P. fagana larval instars, which were light green in color with four white crosslines. The larval period was approx. 24.4 days ($25^{\circ}C$, 16L:8D). Pupae were covered with a light-green membrane and silk. The wingspan of adults was approx. 15 to 18 mm. The color of the forewings of both sexes was bright green. The color of the hindwings was yellow in males and and white in females. First emergence was from early May to late June, and the second emergence was from early July to late August. Pseudoips fagana over-wintered as pupae.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.4
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• pp.249-256
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• 2007

This experiment was conducted to compare the agronomic characteristics and productivity in introduced hairy vetch cultivars and developed new Korean Hairy vetch cultivars in two areas of the experimental field of Grassland and Forage Crops Division, National Institute of Animal Science from 2005 to 2006. The experiment was arranged in randomized complete block design with three replications. A total of 11 hairy vetch cultivars used in this study including 9 introduced cultivars (Penn-02, Sander, Latigo, Welta, Ostsaat, VV4712, Minnie, Barlosa and Capello) and 2 Korean cultivars (Cold green and Cheong pa). The early flowering varieties of Minnie, Barlosa, Capello and Cold green were grown as early maturity cultivars, while the late flowering varieties of Penn-02, Sander, Latigo, Welta, Ostsaat, VV4712 and Cheong pa were grown as medium and late maturity. The winter hardiness of hairy vetch was good except for Minnie, Barlosa and Capello of early maturity cultivars. In this study, dry matter yield of VV4712 was the highest of 11 hairy vetch cultivars. And dry matter yield of medium and late maturity vetch increased in the middle region while that of early maturity increased in the south. The new Korean cultivar, Cheong pa, as a medium and late maturity hairy vetch was not bad compared to introduced cultivars and Cold green as an early maturity hairy vetch was an excellent cultivar compared to introduced cultivars in both regions. Latigo in NDF (neutral detergent fiber) and Welta in ADF (acid detergent fiber) were lower than other cultivars, while Sander in IVDMD (in vitro dry matter digestibility) and CP (crude protein) content were higher than other cultivars. The results of this experiment indicated that the productivity of hairy vetch cultivars was highest in VV4712, and Cheong pa and Cold green of new Korean cultivar were the promising cultivars of hairy vetch in Korea.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.4
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• pp.897-905
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• 2015

This research suggested the traffic signal calculation model of active transit signal priority using a shockwave model. Using this signal priority timing optimization model, the shockwave area is computed under the condition of Early Green and Green Extension among active transit signal priority techniques. This study suggested the speed estimation method of backward shockwave using average travel time and intersection passing time. A shockwave area change is calculated according to signal timing change of transit signal priority. Moreover, this signal timing calculation model could determine the optimal signal priority timings to minimize intersection delay of general vehicles. A micro simulation analysis using VISSIM and its user application model ComInterface was applied. This study checked that this model could calculate the signal timings to minimize intersection delay considering saturation condition of traffic flow. In case studies using an isolated intersection, this study checked that this model could improve general vehicle delay of more over ten percentage as compared with equality reduction strategy of non-priority phases. Recently, transit priority facilities are spreading such as tram, BRT and median bus lane in Korea. This research has an important significance in that the proposed priority model is a new methodology that improve operation efficiency of signal intersection.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.4
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• pp.270-274
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• 2006

A color filter array (CFA) helps a single electrical image sensor to recognize color images. The Red-Green-Blue (RGB) Bayer CFA is commonly used, but the amount of the light which arrives at the photodiode is attenuated with this CFA. Red-White-Blue (RWB) CFA increases the amount of the light which arrives at photodiode by using White (W) pixels instead of Green (G) pixels. However, white pixels are saturated earlier than red and blue pixels. The pseudo multiple capture scheme and the corresponding RWB CFA were proposed to overcome the early saturation problem of W pixels. The prototype CMOS image sensor (CIS) was fabricated with $0.35-{\mu}m$ CMOS process. The proposed CIS solves the early saturation problem of W pixels and increases the dynamic range.