• Journal of Korean Society of Forest Science
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• v.104 no.3
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• pp.411-420
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• 2015

This study examined methods for stand density control by using shape ratio (tree height/DBH) and its application for effective management of Pinus thunbergii coastal disaster prevention forests. We analyzed the present conditions (height, DBH, and density) of P. thunbergii coastal disaster prevention forests at 123 study sites on Jeju Island and west, south, and east coasts of South Korea and compared them with results from previous studies. The average shape ratio for P. thunbergii showed positive correlations with stand density and was significantly higher on the west coast (66.32) than on the south (49.57) and east (48.19) coasts and Jeju Island (48.29). Stands with shape ratio higher than 70 accounted for 50% of the total study sites on the west coast, indicating a decrease in their disaster prevention function compared to that of other previous studies. The stand density in most coastal areas, except the east coast, was significantly higher than the standards recommended by the Korea Forest Service and the Forestry and Forest Products Research Institute of Japan, indicating the need for stand density control. According to the growth estimation equation for P. thunbergii in the coastal area of South Korea, density control is required for young stands less than 14 years old, which show drastic increase in the shape ratio, to conserve their disaster prevention function. Particularly, the first thinning of P. thunbergii forests should be implemented before the stand age of 8 years that a shape ratio exceeds 70. For disaster-prone young stands (${\leq}20cm$ DBH) of P. thunbergii, the stand density was higher in the standard of Japan considering shape ratio than in that of Korea aiming timber production. Hence, the standard guidelines employed in Japan, which assign higher importance to disaster prevention function based on field surveys, can be applied effectively for controlling the stand density of P. thunbergii coastal forests in South Korea, to improve their disaster prevention function.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.7
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• pp.571-583
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• 2006

To secure high yield and good quality of rice, plant growth and nitrogen (N) nutrition status should be taken into account for managing panicle N topdressing (PN). This research aimed at investigating the rice yield response to PN under different plant growth and N nutrition status that was conditioned by different rates of basal and tillering N fertilizer (BTN). Stepwise multiple regression (SMR) was used for the analysis of yield response to (i) BTN and PN, and (ii) shoot N content at PIS (BTNup) and shoot N uptake from PIS to harvest (PNup). Rice yield increased significantly as BTN and PN Increased, but there was no significant interaction between BTN and PN. Yield increased almost linearly with the increasing BTN and PN up to $10{\sim}12$ and $6{\sim}7\;kgN/10a$, and with the increasing BTNup and PNup up to $6{\sim}7$ and $5{\sim}6\;kgN/10a$, respectively. But yield increment tended to decrease above those levels. These declines resulted from the decreased ripened grain ratio and 1000 grain weight even though spikelet number per unit area increased more at above those N levels. Spikelet number per unit area had the linear relationships with the shoot N uptake until heading, and with yield. Like most yield response curves, yield response in this experiment followed the diminishing return function with BTNup, PNup, and plant N uptake from seeding to harvest. Regardless of the degree of BTNup and PNup, yield had a quadratic relationship ($R^{2}$>0.88) with whole shoot N accumulation until harvest, suggesting that the yield determination was closely related with the whole shoot N uptake until harvest regardless of the differences in seasonal shoot N uptake.

• Horticultural Science & Technology
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• v.32 no.3
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• pp.318-329
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• 2014

In order to gain insight into the physiological responses of plants to high temperature stress, the effects of temperature on Chinese cabbage (Brassica campestris subsp. napus var. pekinensis cv. Detong) were investigated through analyses of photosynthesis and chlorophyll fluorescence under 3 different temperatures in the temperature gradient tunnel. Growth (leaf length and number of leaves) during the rosette stage was greater at ambient $+4^{\circ}C$ and ambient $+7^{\circ}C$ temperatures than at ambient temperature. Photosynthetic $CO_2$ fixation rates of Chinese cabbage grown under the different temperatures did not differ significantly. However, dark respiration rate was significantly higher in the cabbage that developed under ambient temperature relative to elevated temperature. Furthermore, elevated growth temperature increased transpiration rate and stomatal conductance resulting in an overall decrease of water use efficiency. The chlorophyll a fluorescence transient was also considerably affected by high temperature stress; the fluorescence yield $F_J$, $F_I$, and $F_P$ decreased considerably at ambient $+4^{\circ}C$ and ambient $+7^{\circ}C$ temperatures, with induction of $F_K$ and decrease of $F_V/F_O$. The values of RC/CS, ABS/CS, TRo/CS, and ETo/CS decreased considerably, while DIo/CS increased with increased growth temperature. The symptoms of soft-rot disease were observed in the inner part of the cabbage heads after 7, 9, and/or 10 weeks of cultivation at ambient $+4^{\circ}C$ and ambient $+7^{\circ}C$ temperatures, but not in the cabbage heads growing at ambient temperature. These results show that Chinese cabbage could be negatively affected by high temperature under a future climate change scenario. Therefore, to maintain the high productivity and quality of Chinese cabbage, it may be necessary to develop new high temperature tolerant cultivars or to markedly improve cropping systems. In addition, it would be possible to use the non-invasive fluorescence parameters $F_O$, $F_V/F_M$, and $F_V/F_O$, as well as $F_K$, $M_O$, $S_M$, RC/CS, ETo/CS, $PI_{abs}$, and $SFI_{abs}$ (which were selected in this study), to quantitatively determine the physiological status of plants in response to high temperature stresses.

• Korea journal of population studies
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• v.29 no.1
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• pp.185-207
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• 2006

Predominant explanations of the persistence of sex segregation ill occupations link job choices to profoundly gendered responses to childbearing and other family demands, arguing that women are more likely to seek jobs which are in some sense compatible with motherhood, either because they are family friendly (flexible, low intensity work) or because they are easy to exit and re-enter. In this paper, I examine the effect of occupational sex segregation on job exits into the labor market among women, with a special attention to the role of childbearing and child rearing. I use data from detailed employment histories gathered from the National Longitudinal Survey of Youth (NLSY) in continuous time event history models. My results indicate that women in female dominated jobs are less likely to exit their jobs than women in other types of occupations. Further this relationship is not shaped by motherhood. While mothers or pregnant women are more likely to leave work, mothers in female-dominated occupations are slightly less likely to leave employment than mothers in other occupations. These results are not consistent with the ideas that women's choice of female-dominated occupations expresses a gendered identity and women strategically seek jobs which accommodate maternal roles. Taken together, my findings do not provide support to the idea that women choose female-dominated occupations because they are easier to integrate with motherhood (except for the pregnancy period).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.1
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• pp.13-26
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• 1994

The present study was focused on investigation of proper processing conditions to develop physicochemical properties of extrudates using sea mustard and corn by single extruder. Response surface analysis was used to evaluate effects of extrusion variables on the quality of the extrudates. Physicochemical dependence variables of sea mustard extrudates with corn grits show a significance correlation of within $5\%$. Among the various dependence variables, the expansion ratio showed a high correlation with bulk density, break strength, water solubility index and yellowness. Bulk density correlated closely with water solubility index; break strength with water absorption index and lightness, and water absorption index with lightness. Water solubility index and lightness showed a significance correlation with yellowness of within $0.5\%$. Three dimensional graphic analysis on response surface regression was conducted with each of the dependent variables which revealed statistically significant relationship to independent variables: $15{\sim}21\%$ moisture content, $10{\sim}30\%$ sea mustard content and $95{\sim}115^{\circ}C$ die temperature. Expansion ratio decreased with increasing moisture and sea mustard content. It showed the highest value at $18\%$ moisture content, $10\%$ sea mustard content and $95^{\circ}C$ die temperature. and the lowest value was at $21\%$ moisture content, $30\%$ sea mustard content and $105^{\circ}C$ die temperature. Bulk density was highest at $21\%$ moisture content, $30\%$ sea mustard content and $105^{\circ}C$ die temperature. On the other hand, it was lowest at $18\%$ moisture content, $10\%$ sea mustard content and $95^{\circ}C$ die temperature. Break strength was highest at $18\%$ moisture content, $10\%$ sea mustard content and $115^{\circ}C$ die temperature, but lowest at $21\%$ moisture content, $30\%$ sea mustard content and $105^{\circ}C$ die temperature. Water solubility index increased in the range of $43.9{\sim}54.8\%$ as the moisture content increased.

• Management & Information Systems Review
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• v.31 no.3
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• pp.223-248
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• 2012

This study analyses support policy and structural change of textile industry in Daegu Kyungbuk region, and suggests major issues for textile industry's innovation. In Daegu Kyungbuk, it was 1999 that a policy, so called Milano Project, in order to promote a textile industry was devised. In 2004, the Regional Industrial Promotion Plan was devised. The plan was born from a view point of establishing a regional innovation system and of promoting the innovative clusters under a knowledge based economy. After then, the Regional Industry Promotion Project or Regional Strategic Industry Promotion Project became a core of regional textile industrial policy. Research results indicated that the first stage Milano project (1999-2003) showed both positive and negative effects. There were no long-term development plan, clear vision and strategy. But, core industrial infrastructure for differentiated product development, such as New product Development Support Center and Dyeing Design Practical Application Center, was constructed. The second stage Daegu Textile Industry Promotion Plan (2004-2008) displayed a significant technological performance and new product sales with the assistance of Kyungbuk province. Also, textile industry revealed positive fruits such as financial structure, productivity, and profitability as a result of strong restructuring. In industrial structure, there was a important change from clothe textile material to industry textile material. Most of textile companies did not showed high capability in CEO's technology innovation intention, entrepreneurship, R&D and human resource competency in compare with other industry. We suggested that Daegu Kyungbuk has to select and concentrate on the high-tech textile material and living textile for sustainable development and competitiveness. We also proposed a confidence and cooperation based innovation network and company oriented innovation cluster.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.3
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• pp.233-245
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• 2014

Nighttime correction of $CO_2$ flux is one of the most important and challenging tasks in eddy covariance measurements over a complex mountainous terrain. In this study, we have scrutinized the quality and the credibility of the $CO_2$ flux datasets which were produced by employing three different methods of nighttime correction, i.e., (1) friction velocity ($u^*$) correction, (2) light response curve (LRC) correction, and (3) advection-based van Gorsel (VG) correction. The whole year datasets used in our analysis were collected at the two KoFlux tower sites (i.e., GDK deciduous forest site at the upper hill and GCK coniferous forest site at the lower hill) located in the valley of Gwangneung National Arboretum in central Korea. The resultant magnitudes and patterns of ecosystem respiration ($R_E$), gross primary productivity (GPP), and net ecosystem exchange (NEE) of $CO_2$ showed marked differences among the datasets produced with three different correction methods, which were also site-specific. The examination from micrometeorological and ecological perspectives suggests that the major cause of some inconsistency seems to be associated with the advection of $CO_2$ along the sloping terrain and the inappropriate selection of the correction data that might have been already affected by advective flows. The comparison with the results from other studies indicated that the overall characteristics of the corrected $CO_2$ fluxes at GDK and GCK (except those with LRC correction) were well within the ranges reported in the literature for various ecosystems in East Asia in similar latitudes. However, our study also implies that there will be always a room for further improvement in the present datasets. Therefore, caution must be exercised for the data users in order to properly use the updated version of datasets through transparent, open and participatory communication with data producers.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.2
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• pp.79-86
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• 2016

The late-maturing black rice cultivar Shinnongheugchal from Jeollabuk-do Agricultural Research and Extension Service was used as the plant material for estimating growth characters, quality and yield from the vegetation period to harvest age. This study was performed to select an optimum combination of nitrogen level and planting density for the maximum yield of Shinnongheugchal. The plant height, number of tillers, and SPAD index were higher when the combination of 70 hills per $3.3m^2$ and 13 kg/10 a nitrogen level was used at 30 days after transplanting. The heading date for the combination of 70 hills per $3.3m^2$ and 15 kg/10 a nitrogen level, and 80 hills per $3.3m^2$ and 15 kg/10 a nitrogen level was August 22. The heading date for the other combinations was August 21. The combination of 70 hills per $3.3m^2$ and 13 kg/10 a nitrogen level yielded the highest number of tillers at 40 days after flowering. Even though the lodging index was increased with increasing nitrogen levels, field lodging did not occur until harvest time. Seed nitrogen concentration in the combination of 70 hills per $3.3m^2$ and 13 kg/10 a nitrogen level showed a significant difference when compared with the other combinations. The black rice yield varied significantly, and the highest yield was observed in the combination of 70 hills per $3.3m^2$ and 13 kg/10 a nitrogen level. The yield was significantly correlated with seed nitrogen concentration. The maximum yield was estimated to be 14.67 kg/10 a nitrogen level by using the regression equation. On average, the coloring degree of the black rice was higher at planting density of 70 hills per $3.3m^2$ than at 80 hills per $3.3m^2$. The highest yield of perfect black rice was obtained using the combination of 70 hills per $3.3m^2$ and 13 kg/10 a nitrogen level. Our findings demonstrate that a nitrogen level of 13-14 kg/10 a can be used to obtain the maximum yield from Shinnongheugchal with yield, cyanidin 3-glucoside content, and perfect black rice yield as the standard.

• Horticultural Science & Technology
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• v.34 no.1
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• pp.77-83
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• 2016

The measurement of total fresh weight of plants provides an essential indicator of crop growth for monitoring production. To measure fresh weight without damaging the vegetation, image-based methods have been developed, but they have limitations. In addition, the total plant fresh weight is difficult to measure directly in hydroponic cultivation systems because of the amount of nutrient solution. This study aimed to develop a real-time, precise method to measure the total fresh weight of Romaine lettuce (Lactuca sativa L. cv. Asia Heuk Romaine) with growth stage in a plant factory using a nutrient film technique. The total weight of the channel, amount of residual nutrient solution in the channel, and fresh shoot and root weights of the plants were measured every 7 days after transplanting. The initial weight of the channel during nutrient solution supply (Wi) and its weight change per second just after the nutrient solution supply stopped were also measured. When no more draining occurred, the final weight of the channel (Ws) and the amount of residual nutrient solution in the channel were measured. The time constant (${\tau}$) was calculated by considering the transient values of Wi and Ws. The relationship of Wi, Ws, ${\tau}$, and fresh weight was quantitatively analyzed. After the nutrient solution supply stopped, the change in the channel weight exponentially decreased. The nutrient solution in the channel slowly drained as the root weight in the channel increased. Large differences were observed between the actual fresh weight of the plant and the predicted value because the channel included residual nutrient solution. These differences were difficult to predict with growth stage but a model with the time constant showed the highest accuracy. The real-time fresh weight could be calculated from Wi, Ws, and ${\tau}$ with growth stage.

• Korea journal of population studies
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• v.11 no.1
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• pp.50-57
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• 1988

This study focused on the anding of Inchon's identity The empirical method and ethnomethodological approaches were used to collect the data. Among members ofcitizen movement groups,government workers,and students who are living inInchon were selected as 613 samples using a purposive sampling method. MultipleClassification Analysis (MCA) and cross-tabulation methods were used in theanalysisThe study of identity in an area is important in terms of providing the solution ofthe problem in a region and social integration of the citizens. The scores of the indexabout Inchon's identity are quite low and more than half of the respondents to allthree groups showed the middle position of the scores from the identity index. By thecharacteristics of the respondents,female,unmarried single,30 years or more,lowerincome groups showed relatively higher identity index scores than other counter-parts . And professional,administrative,clerical workers'identity index scores werehigher than people who work at sales,service,and agricultural sectors. Respondentswith 2 years of college or more,with intentions to donate special monies for cultural, social welfare, environmental reform,persons who want to live in Inchon for along period of time equipped with a stronger identity index.For the character of Inchon's identity,there are no identity,making it fromnow on,capacity or broad-minded city,vanguard pioneer,displeased, Oiversity/multiplicity of the city,defense spirit from foreign invasion,entrancecity from the world in that order. Therefore,it is hard to say what exactly Inchon'simage is in a single word. However,Inchon can be characterized as a diverse citywith capacity to live together without any serious conflicts among citizens who come from Seoul,Kyunggi-Do,Chungchung-Do,Chunla-Do,Kyungsang-Do,and foreign countries including North Korea. These facts imply that Inchon should continue topursue this image as a diverse city with capacity as an identity pursuing towardsworld city and hub city of North East Asia.ty as an identity pursuing towardsworld city and hub city of North East Asia. East Asia.