• Journal of the Korean Wood Science and Technology
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• 제18권4호
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• pp.65-78
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• 1990

For the purpose of Improving the sounding boards for the conventional GAYAKUM, I was making approximately 202 specimens of radial board, 371 specimens of tangential board by cutting along the grain and the part of stem and 31 specimens of the disjointed traditional GAYAKUM made in Paulownia coreana. And it was conducted to measure specific gravity, dynamic Young's modulus, internal friction, resonant frequency, velosity of sound and width of annual ring by the method of the frexural vibration in a free-free bar in the audio frequency range. And it confirmed the juvenile wood by measuring wood fiber length of specimens. It was also conducted to investigate dynamic properties and moisture absorption by various heat-treatment and to test dynamic Young's modulus and internal friction for the disjointed conventional GAYAKUM. The results obtained were summarized as follow: 1. The Juvenile wood is located within about 7 annual rings from the pith in Paulownia coreana. 2. As increased with the specific gravity, the dynamic Young's modulus had more and more increased, but the internal friction had slightly decreased. 3. I think that radial board would be good for sounding board wood. because radial board is higher than tangential board in dynamic Young's mudulus and internal friction is lower than tangential board. 4. The value of mean dynamic Young's modulus on the conventional GAYAKUM, radial board and tangential board of 604 samples is $0.4283\pm0.037(\times10^{11}dyne/cm^2)$, $0.4316\pm(\times10^{11}dyne/cm^2)$ and $0.4234\pm0.112(\times10^{11}dyne/cm^2)$ respectively. The value of the radial board showed little higher than that of conventional GAYAKUM, but It had a similar tendency between conventional GAYAKUM and tangential board. 5. The annual ring width by four aspect is more narrow in north and west than that of others. 6. The values of specific gravity and dynamic Young's modulus in the mature wood showed higher than those of juvenile wood. 7. As the grain angle in the butt wood more increased to bark from pith, the dynamic Young's modulus were low. Then it was not good for sounding board. 8. It appeared that the heat-treatment for sounding board wood had a more effect to do the treatment of hotiron on surface after heat-treatment during 24 hours in $60^{\circ}C$ temperature. 9. As increased with the temperature, the rate of moisture absorption of heat-treatment wood had decreased. In conclusion, I thought that the sounding board wood for GAYAKUM would had the most effect to do the treatment of hotiron on surface after heat-treatment during 24 hours in $60^{\circ}C$ temperature using the radial board of mature wood.

• Korean Journal of Environmental Biology
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• 제27권2호
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• pp.155-163
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• 2009

The Oriental white stork (Ciconia boyciana) is an endangered species in Korea as well as in the world. In order to provide information on foraging habitats for releasing storks to the wild, we studied the foraging behavior of the species according to different food densities and water levels. We released two individuals, male and female, after enclosing a study site with a fence and cutting out a part of two or three primary feathers. Research was conducted from 20 June to 16 August 2008 at Whawon-ri, Mewon-myung, Chungcheongbuk-do, South Korea. We investigated habitat patch usage, foraging efficiency, and foraging methods of the feeding individuals in the different food densities and water levels. The storks invested more for foraging time and trials, and they captured more food in a habitat of high food density than others. The female invested more time and captured food most in a habitat of lowest water depth while the male in a habitat of middle water depth. However, foraging efficiency did not differ significantly among habitats of food density and water depth, and only differed between male and female by ways of foraging method. From this study we suggest that the storks select foraging habitats and foraging methods under different conditions of food density and water depth.

• Journal of the Korea institute for structural maintenance and inspection
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• 제16권5호
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• pp.129-136
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• 2012

Temperature of fresh concrete can be effectively used to predict the strength of concrete being cured and make an informed decision for stripping the molds. A hygrothermograph and thermo-couple sensors that require an extensive wiring have been applied to measure a temperature of concrete at the early stage of the curing process on site. However, these methods have limits to provide the temperature data in real time due to harsh working environment including frequent cutting of wires. Therefore, this study is aiming at developing a device based on wireless sensor network to measure the temperature of concrete being cured in formwork. The result showed that the wireless sensor with probe type thermistor which is developed had the same temperature data compared to the existed wire type thermistor, and we confirmed the temperature history of concrete in real time for 28 days throughout the gateway by wireless network that collects the temperature data measured from specimens in laboratory. Also, the network device for transmission can be easily separated from the probe sensor part and reused consistently. If the wireless sensor network device developed uses in the field, the temperature management of concrete will be systematically conducted from at the early stage of the curing, and especially be effective for cold weather concrete construction. In addition, it will contribute to the establishment of advanced quality control system for concrete and productivity of supervisors on site will be increased in the future.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제53권1호
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• pp.28-33
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• 2008

Traditionally mungbean (Vigna radiata L.) sprouts has been stored after dehydration to decrease their decay. The study was done to determine the effect of watering for final 12 hours of harvest day on morphological characters and color of mungbean sprouts. The seeds of cv. Zhong Lu 1 were soaked in 50 ppm BA solution immediately before 4 hour aeration and then cultured for 6 days, when water-supplied for final 12 hours or not. After packaged with PE envelops, the sprouts stored 5 days at $8^{\circ}C$, and their morphological characters, fresh and dry weights, and colors were measured everyday. Compared to non-water supplied, water supplied sprouts had thicker hypocotyl diameter in middle part, and higher total fresh weight due to increment of cotyledon and hypocotyl ones although the two sprouts did nearly same in other characters. Only nonwater supplied sprouts showed higher color b value in hypocotyl than water supplied ones although there were not significant differences between them in other color-related characters, meaning that the latter ones were more rapidly decayed during their storage. In non-water supplied sprouts, number of lateral roots, hypocotyl and root lengths, total fresh weight, brightness of hypocotyl and root was decreased since 3 days after storage but cutting resistance of hypocotyl was done since 5 days.

• Korean Journal of Environmental Biology
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• 제26권2호
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• pp.121-127
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• 2008

As a step toward developing conservation and restoration plans for an endangered species of the Oriental White Stork (Ciconia boyciana), we studied daily foraging behavior and ecology. We released two individuals, male and female, after enclosing study site with a fence and cutting out a part of two or three feathers of primaries. Research was conducted from 16 June to 11 July, 2007 for 25 days at Whawonri, Mewonmyung, Chungbuk province. We investigated diural and daily variation of foraging time budget, diet composition, and habitat selection of the feeding individuals. The storks quadratically invested for foraging time and resting time according to time of day, but no significant variation in the foraging time and resting time appeared daily over 25 days. As a result, the storks mainly used wetland as a foraging site in the center of the study area to that in the edge as well as to other types of habitat. The high usage for wetland in the center did not change over the 25 days while Rice field decreased and Wetland in the edge and Pathway increased. Female invested more time for foraging than male, but the foraging efficiency did not differ between them. We discussed the significance of foraging behavior and habitat selection for management plan.

• Journal of the Economic Geographical Society of Korea
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• 제17권4호
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• pp.743-758
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• 2014

It has widely been recognized that the EXPO 2012 Yeosu Korea was a succeeded mega event, according to, at least, the international media's attention and reports. This study analysed and compared the trends of the international media's reports on Yeosu in terms of before, preparing, during, and, after periods of the event, through a semantic network analysis. It was revealed that the images of Yeosu have dramatically been upgraded. The city of Yeosu, before the event, was a small port city of South Korea's southern part of peninsula. The city, after the nomination for the next host city of the exposition, was described to a city who had a full potentiality to host a world exposition, not a southern port city of South Korea. After the event was opened, Yeosu was a city of cutting-edge technology and cultural creativity, who had contributed to solve our humankind's pending ecological problems. Even after the events closed, Yeosu was continuously impressed as a ex-city of world exposition, a hub city of Asia trade, and a center for marine ecological restoration. It was suggested that extended monitoring, differentiated communication strategies, long-term planning, and professionalization of the staffs.

• Korean Journal of Environment and Ecology
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• 제27권5호
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• pp.571-578
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• 2013

This study generated regression models through a direct harvesting method to estimate carbon storage and uptake by Pinus densiflora and Pinus koraiensis, the major evergreen tree species in urban landscape, and established essential information to quantify carbon reduction by urban trees. Open-grown landscape tree individuals for each species were sampled reflecting various diameter sizes at a given interval. The study measured biomass for each part including the roots of sample trees to compute the total carbon storage per tree. Annual carbon uptake per tree was quantified by analyzing radial growth rates of stem samples at breast height. The study then derived a regression model easily applicable in estimating carbon storage and uptake per tree for the two species by using diameter at breast height (DBH) as an independent variable. All the regression models showed high fitness with $r^2$ values of higher than 0.98. While carbon storage and uptake by young trees tended to be greater for P. densiflora than for P. koraiensis in the same diameter sizes, those by mature trees with DBH sizes of larger than 20 cm showed results to the contrary due to a difference in growth rates. A tree of P. densiflora and P. koraiensis with DBH of 25 cm stored 115.6 kg and 130.0 kg of carbon, respectively, and annually sequestered 9.4 kg and 14.6 kg. The study has broken new grounds to overcome limitations of the past studies which quantified carbon reduction of the study species by substituting, due to a difficulty in direct cutting and root digging of landscape trees, coefficients from forest trees such as biomass expansion factors, ratios of below ground/above ground biomass, and diameter growth rates.

• Journal of Korean Society of Forest Science
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• 제1권1호
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• pp.12-21
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• 1962

Outdoor cuttings studies on two coniferous species, pitch pine and needle fir, have been made at Suwon, Korea extending from March to early May, 1956. The purpose of these studies was to find the effects of ages of parent trees, topophysis, dilute hormone solution treatments and the time at which the cuttings were collected on the rooting response of the cuttings. On September 2, rooting results were examined. Pitch Pine (Pinus rigida) The total of 1335 cuttings were collected from 3- and 10-year old trees. The cuttings treated were planted on March 13 and April 20. 1. In the cuttings collected from 3-year-old seedlings, the best result (34 percent rooted) was obtained by treating ends of cuttings with a mixture of 50 ppm IBA and 50 ppm NAA. 2. No rooting was observed in lammas shoots. 3. The cuttings from 3-year-old seedlings gave better rooting than those from 10-year-old trees. 4. The root origins were developed from the lower part of the cutting and the cut surface. Needle fir (Abies holophylla) One hundred twenty-five cuttings were collected from a 30-year-old tree. The cuttings treated with any one of four mixed hormone solutions were planted on March 23. 1. Fifteen cuttings out of 75 cuttings from the lower half of the crown were rooted. The cuttings obtained from the upper half of the crown did not root at all. 2. The cuttings treated by the hormone solution made up of 20 ppm IAA, 20 ppm IBA, 20 ppm NAA, 20 ppm thiamine and 5 percent sucrose gave the best rooting (22 percent). 3. All roots originated from callus tissues and irregularly arranged parenchymatous tissues near the cut base.

• Korean Journal of Social Welfare
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• 제56권3호
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• pp.279-301
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• 2004

Relations of factors associated with burnout were investigated among 124 child protective service workers currently working in Korean Child Abuse Prevention Centers nationwide. Three categories of factors associated with burnout were examined; (1) individual characteristics, (2) job-related characteristics, and (3) job-satisfaction. Social survey method using questionnaires by mail was employed. MBI(Maslach Burnout Inventory) for measuring burnout, a part of Smith, Kendal & Hulin's JDI(Job Description Index) for job-satisfaction, and a scale measuring the special characteristics of job developed by researchers were used. Mann-Whitney test and Kruskal-Wallis test were employed to analyze the data. Across all burnout sub-scales(emotional depletion, dehumanization of clients, lack of feelings of achievement), subjects reported a high degree(above the cutting point) of burnout. Several factors were identified as associated with burnout. Child protective service workers who are young, single with front line worker status reported higher burnout. Lack of education and training before the job location were another factors which contributed to worker burnout. Lack of proper supervision stood out as another burnout provoking factor. Job-satisfaction was negatively correlated with all three burnout sub-scales, which meant the lower the job-satisfaction, the higher the burnout of service workers. The findings implicate that the administrators of Child Abuse Prevention Centers should pay close attention to their workers' sign of burnout and develop carefully designed support system which include provision of excellent supervision, proper education and training opportunities and organizational effort to strengthen employees' overall job-satisfaction to secure their quality of services toward abused children and their family.

• Journal of the Korean association of regional geographers
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• 제7권2호
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• pp.71-81
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• 2001

According to the change of stream power/resisting power relationship due to the crustal movement or the climatic change, most channel landforms which reflect the equilibrium state of fluvial system are eroded and a part of them is remained as a river terrace. In many rivers in Korea are extensively distributed the relatively younger low river terraces. But their accurate formation mechanism is not known. In this paper, the formation processes and the dating of low river terraces distributed in Nakdong River basin will be investigated. Stream power of the downward erosion was revived because the sea level fell down. So stream power was superior to the resisting power under the cool-wet climatic condition during the last glacial period. Thus the river bed was excavated deeply, so that low river terraces were built up. And many incised meander loops were cut during this period. But, when fluvial system did not have equilibrium over all reaches, the last glacial period ended and the sea level initiated to rise rapidly. The headward erosion from the fall of sea level during the last glacial period had kept up to Hagye Fall because of the cutting of incised meander loops. Deeply excavated valleys and abandoned channel of cut-meander in lower reaches of a stream were filled with sediments. Thus the longitudinal profile of the uppermost reaches reflect the last interglacial, the upper reaches the last glacial, and the middle/1ower reaches recent fluvial system. Therefore low river terraces have been formed since the last glacial period.