• Journal of the Korean Operations Research and Management Science Society
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• v.40 no.1
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• pp.139-154
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• 2015

This paper uses the Heckman model to evaluate the income difference between the public sector and the private sector based on the CHNS data. The research finds that the difference of the public sector versus the private sector between the west area and the east area is about 10% from 1989 to 2000, the transition of the income difference is smooth, that data has made sharp increase to 32% from 2000 to 2011. Considering the income difference between the west area and the central area, the central area and the east area from 1989 to 1997, the data is about 10~15%, from 2000 to 2011 is rocketing time, the data reaches 20%. This paper is very revealing about the income difference ofthe public sector versus the private sector is increasing year after year, and the economy is developing rapidly but with imbalance among different areas in China. It would provides the reference for adjust the income distribution system in future.

• Proceedings of the KSRS Conference
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• v.2
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• pp.918-921
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• 2006

The short-term variation of sea surface temperature before and after typhoons and increase of chlorophyll a concentration that accompany with the typhoons during summer in the East/Japan Sea were explored by satellite. Four typhoons (NAMTHEUN, MEGI, CHABA and SONGDA) and a typhoon (NABI) passed over the East/Japan Sea in 2004 and 2005, respectively. Decreasing of SST was observed in the every five typhoons, however the magnitude of SST decreasing were various from 1 to $5^{\circ}C$. Chlorophyll a increases were found after the typhoons (0.1-3 ${\mu}g$ $l^{-1})$ except NAMTHEUN, and the area was approximately included in SST decreasing area by the typhoons. It suggests that chlorophyll a increase was caused by nutrient input from subsurface layer by strong mixing. On the other hand, rarely chlorophyll a increase was observed in northern area of polar frontal zone, which is located in $38-41^{\circ}N$, than northern area, and chlorophyll a increase in coastal area was higher (more than 3 times) than offshore area. It might suggest that chlorophyll a increase in the East/Japan Sea is also related with the depth or nitracline depth that affects the amount of nutrients supply to the upper layer by typhoon mixing.

• Journal of Ginseng Research
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• v.15 no.1
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• pp.31-35
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• 1991

In order to know the optimum planting density under shading structures at different light intensity, We investigated the growth status, distribution of ginseng leaf area, correlation between planting density and root weight per plant and yield, correlation between leaf area index and root weight per plant and yield. According to the increase of planting density the leaf area per plant was decreased, but leaf area index (L.A.I) was increased. Ginseng leaf population at different lines under common straw shading were distributed mainly in frost lines but polyethylene net shading at 10fo light intensity were distributed equally in all lines. Optimum planting density in common straw shading at 5% light intensity was 55 plant per tan (90 cmX180 cm) and polyethylene net shading 81 10% light intensity was 60 plant per tan, in consideration of root weight and yield. Optimum leaf area index was 2.4 under common straw shading at 5% light intensity but was 2.7 under polyethylene net shading at 10% light intensity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.612-621
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• 2011

The influences of inland pollution sources because of rainfall events on the bacteriological water quality in Geoje Bay, a major shellfish production area in Korea, were investigated. The sanitary status of sea water and shellfish after rainfall events was also evaluated. The flow rates of 13 streams around Geoje Bay showed 6 to 7-fold increases after 15 to 21 mm of rainfall. Peak pollution was observed in the Naegan Stream, the Gandeok Stream and the Seojeong Stream. The calculated impact area of inland pollution sources was 3.1 $km^2$ immediately after 15 mm of rainfall and expanded to 3.5 $km^2$ after 24 hours. These calculations of impacted area matched results from fecal coliform analyses with sea water. The distance between the major pollution source in the bay (the Gandeok Stream) and the station with the worst bacteriological water quality immediately after 15 mm of rainfall, which was below the Korean standard, was 0.8 km in a straight line; this distance increased to 2.0 km after a period of 24 hours. The area impacted by inland pollution sources after a 15 mm rainfall event was wider than after a 21 mm rainfall. Although the flow rate from inland pollution sources was higher, the concentration of fecal coliform in the discharged water was lower after higher rainfall events. These observations corresponded with the results of fecal coliform analyses with sea water samples. According to the evaluation of the influences of inland pollution sources and fecal coliform analyses on sea water and shellfish samples in Geoje Bay, pollutants from inland sources did not reach the boundary line of the shellfish growing area after rainfall events of 15 or 22 mm. The bacteriological water quality of the shellfish growing area in Geoje Bay met the Korean standard and US NSSP requirements for approved shellfish growing areas.

• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.159-164
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• 2005

In this paper, we study some problems of the scheduling on the fixed area in a shipbuilding. The scheduling, constrainted a working area, is not easy to make a load balance and to operate a change of daily work plan. we proposed a block arrangement algorithm to make the load balance and developed a system used to operate the change of daily work plan.

• ETRI Journal
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• v.44 no.4
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• pp.543-559
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• 2022

To determine a suitable waveform for Internet of Things (IoT) transmission over low-Earth orbit (LEO) satellites, this paper reports the results of a performance comparison between chirp spread spectrum (CSS)-based LoRa and direct sequence spread spectrum (DSSS)-based Ingenu. The performance of both waveforms was measured in terms of the packet error rate, throughput, and packet loss rate, considering the Doppler effect caused by the high speed of LEO satellites and the interference among multiple terminals. Simulation results indicate that the DSSS scheme is more suitable than the CSS scheme for high-traffic IoT services because of its robustness against interference among multiple terminals. However, the CSS scheme is more suitable than the DSSS scheme for high-mobility IoT services because of its robustness against the Doppler effect. We discuss various solutions, such as the preprocessing of Doppler effect and avoidance of packet collision, to enhance the performance of the DSSS and CSS schemes. The simulation results of the proposed solution show that the enhanced DSSS scheme can be a proper waveform in IoT transmission over LEO satellites for both the high-traffic and high-mobility services.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.6
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• pp.79-89
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• 2012

This study was compared to the differences in the habitat, species composition and community structure of revegetation and nature area in Korea. Plant number in plot of revegetation and nature area was 10.3 and 15.0 taxa, respectively, and coverage was 90.6 and 88.1%, respectively. Revegetation and nature area was very heterogeneous, due to low similarity index (0.38) and less common plants. Festuca arundinacea frequency (56.7%) was highest in revegetation area, and Oplismenus undulatifolius frequency (66.7%) was highest in nature area. Plant appearing of revegetation and nature area was 111 and 136 taxa, respectively. Herb appearing of revegetation and nature areas was 93 (83.3%) and 72 (52.9%) taxa, respectively, tree was 18 (16.2%) and 64 (47.1%) taxa, respectively. Plant communities of revegetation area was classified into Lespedeza bicolor, Indigofera amblyantha, Alnus sibirica, Festuca arundinacea, Eragrostis curvula, Miscanthus sinensis, Humulus japonicus, Setaria faberii, Rudbeckia bicolor, Pueraria lobata community. Plant communities of nature area was classified into Pinus densiflora, Quercus aliena, Quercus acutissima, Quercus variabilis, Quercus serrata, Castanea crenata, Pinus rigida, Robinia pseudoacacia, Populus tomentiglandulosa, Phyllostachys bambusoides community. Habitat, species composition and community structure of revegetation and nature area showed a large difference.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.1
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• pp.107-117
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• 2012

We estimated the potential area roof greening in Gyeonggi-do that will mitigate the heat island effect. The estimation was based on building age, roof shape, and building use which were recorded in the building register from "Sewoomteo, the Building Administration System in the Ministry of Land, Transport and Maritime Affairs. The estimated potential roof greening area in Gyeonggi-do was approximately $102.5km^2$ assuming that the buildings for residence, public, education(school), office, shopping mall are appropriate for roof greening. The area occupied by apartment buildings over six-story was 76.3% of the potential roof greening area 10.2% for individual houses, 5.9% for under five-story apartment buildings, and 3.7% for school buildings. The result indicated that it is residential buildings that we need to pay attention for roof greening, especially high-rise buildings over six-story. Greening of the whole estimated area, $102.5km^2$, in Gyeonggi-do will result in the increase of green space per capita by $8.74m^2$. This is 1.65 times greater than the area of current urban parks, and 1.97 times greater than the total area of neighborhood parks, children's parks, and pocket parks. Greening of the estimated roof area will increase green coverage of urban area by twice, adding to current green coverage of the urban areas, 11.3%, in 10 major cities. In particular, the effect of roof greening would be remarkable in inceasing the green space of Anyang City, Gwangmyeong City, and Guri City where neighborhood park area falls short.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.2
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• pp.139-145
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• 2011

Hydro-acoustic survey was carried out to estimate a fish distribution at marine ranching area and aggregated fish schools at artificial reef area in Oeyeondo, Korea. The survey system was set up with DGPS system, scientific echo sounder (EK60, Simrad Co.), and ECDIS (Mecys. Co. LTD). A track survey and a random survey was respectively applied to the marine ranching area (474.4ha) and to the artificial reef area (within a radius of 300m). As the result, fish distribution and MVBS values in marine ranching area showed that created fisheries resources didn't come to be abundant yet as to appear fish distribution in all of the area. In the artificial reef area, it was, however, able to detect many fish school signals on the top of and around artificial reefs and to confirm the luring effect of artificial reefs.

• Korean Journal of Plant Resources
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• v.20 no.1
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• pp.1-6
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• 2007

The vegetation of habitats of a Korean rare plant Kirengeshoma koreana Nakai at Mt. Baekun was investigated by phytosociological approach. The vegetation of investigated area shows typical southern-temperate Quercus forest. The humidity of soil was high and the ground of locality was flat area of sub-alpine. These investigated area is very important for conservation of a rare plant, Kirengeshoma koreana that is limited in this area. Therefore, sustainable conservation strategy such as designation of conservation area should be prepared urgently by the results of long-term monitoring studies.