• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.4
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• pp.85-93
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• 1988

This laboratory study was carried out in order to produce fundamental data for analyzing salt movement and desalinization effects, using samples of silt loam soil collected in Gyehwado and Daeho reclaimed tidelans, and samples of silty clay loam soil collected in Kimie tideland. Desalinization experiments with gypsum treatment were performed to analyze changes of the hydraulicc conductivity with changes of the soil property and the salt concentration during the desalinization of reclaimed tideland soils by leaching through the subsufface drainage, and correlations between factors infl uencing the reclamation of salt affected soils were analyzed by the statistical method. The results were summarized as follows: 1. The reclaimed tideland soils used in this study were saline-sodic soils with the high exchangeable sodium percentage and the high electrical conductivity. 2. Changes of the hydraulic conductivity with the amount of leaching water and the leaching time elapsed were affected by the amount of gypsum except exchangeable sodium and clay contents. The regression equation between the depth of water leached per unit depth of soil (Dw / Ds : X) or the square root of the leaching time elapsed (T $^1$ $^2$ : X) and the relative hydraulic conductivity (HCr:Y) could be expressed in Y=a . bx. 3. The more exchangeable sodium and clay contents regardless of the amount of gypsum, the more the leaching time was required until a given volume of water was leached through the soil profile. The regression analysis showed that the relationship between the depth of water leached per unit depth of soil(Dw /Ds:X) and the square root of the leaching time elapsed(T$^1$$^2$ :Y) could be described by Y=a . Xb. 4. The hydraulic conductivity was influenced to a major degree by the salt concentration provided that the electrical conductivity was below 10 mmhos / cm during the desalinization of reclaimed tideland soils. The regression equation between the relative electrical conductivity ( ECr : X) and the relative hydraulic conductivity (HCr:Y) could be expressed in Y=a + b . X-$^1$. 5. In conclusion, the hydraulic conductivity, leaching requirements and the leaching time elapsed can be estimated when the salt concentration decreases to a certain level during the desalinization of reclaimed tidelands, and the results may be applied to the analysis of salt movement and desalinization effects.

• Journal of Family Resource Management and Policy Review
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• v.10 no.3
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• pp.131-148
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• 2006

The purpose of this study is to examine the allocation of time between work and leisure by the rural elderly in Korea. The data used for this study are collected from fm households during the peak ($17^{th}\;to\;30^{th}$ June) and off-peak ($28^{th}$ November to $10^{th}$ December) farming seasons of 2005 using time diary. The sample for this study consists of 120 elderly over 65 years old living in rural area in eight provinces. The major findings are as follows. (1) The time spent of farm work by rural elderly in much longer than average work hours of elderly in general regardless of farming season. The indicates that the elderly farmers are the sustaining forces of agriculture as the urban industrial sector absorbs the younger labor force rural area. (2) There are significant differences in the work time(including form work, housework, and farm work plus house work) by gender, age, education, marital status, living arrangements. (3) The rural elderly spends less time in leisure compared to the elderly in general even during the off-peak season. (4) Especially during the peak season, time allocation between work and leisure by the rural elderly is heavily skewed, resulting in an inadequate amount of time for reproduction of labor. (5) There is only significant age difference in the amount leisure time regardless of farming season. (6) Male elderly farmers work approximately 30 minutes to 1 hour longer on farm than the females do, but the total work time (farm work plus housework) of female elderly is longer than that of the male elderly. There is no significant gender difference in the amount of leisure time during the peak season, whereas the men have more leisure than the women during the off-peak season. To conclude, the gender differences in time allocation among the rural elderly are minimal. However, the rural elderly of both genders suffers from excessive work hours and heavy workload compared to the urban counterpart.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.3
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• pp.286-292
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• 2010

In this paper, we investigate the relationship between the performance of telerobotic systems and the two independent time-delay on different modality, which are haptic and video. Especially, we try to find some performance improvement when the amount of delay of haptic and video is synchronized. Experiments were conducted with 10 subjects by scanning the amount of video and haptic delay independently. It is rather interesting to note that the teleoperation performance was not that sensitive to video delay, and the synchronized video and haptic delay doesn't show better performance than the case when haptic delay is lower than video delay.

• Journal of the Korean Geosynthetics Society
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• v.22 no.2
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• pp.71-83
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• 2023

It is very important to predict the amount of settlement in order to maintain the function of the coastal structure. Finite element analysis methods and real and model experiments are used as methods for this, but this has the disadvantage of requiring a lot of cost and time. Therefore, this study was conducted for the purpose of a simple formula proposal that can easily predict the amount of settlement of the caisson-type quay wall structure. In the research process, after calculating the PSI (Power Spectrum Intensity) of the velocity, the amount of settlement of the structure is calculated by substituting it into the simple formula of the existing gravity breakwater. By comparing and analyzing the amount of settlement of the structure obtained through numerical analysis, it was confirmed that the error between the amount of settlement of the existing simple formula and the amount of settlement of the numerical analysis was large, and it was confirmed that the background could not be considered in the case of the existing simple formula. Therefore, this study proposed a correction factor for the background of the quay wall structure, indicating a simple formula that can obtain the amount of settlement of the caisson-type quay wall structure. Compared to the numerical analysis settlement amount, it was judged that this simple formula had sufficient precision in calculating the caisson-type quay wall settlement amount. In addition, facilities vulnerable to earthquake resistance can be easily extracted in situations where time and cost are insufficient, and it is expected to be used as a screening technique.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.286-296
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• 2023

This study was conducted to evaluate the effects of soil microbial fertilizer (SMF) containing Saccharomyces cerevisiae HS-1 and Streptococcus thermophiles HS-2 on the growth of creeping bentgrass. For the pot experiment, the treatments were as follows: no fertilizer (NF), control (3 N g/m²/month), SMF-1 (control+SMF 2 mL/m²/time), and SMF-2 (control+SMF 4 mL/m²/time). For the plot experiment, the treatments were as follows: NF, control, SMFp-1 (control+SMF 1 mL/m²/time), SMFp-2 (control+SMF 2 mL/m²/time), and SMFp-3 (control+SMF 4 mL/m²/time). In the pot experiment, visual turfgrass quality and the uptake amount of nitrogen (N) and potassium (K) were increased under the SMF treatments, whereas the content of chlorophyll (a, b, and a+b) and clipping yield were not considerably different compared with the control. In the pot experiment, the amount of SMF positively correlated with visual turfgrass quality and uptake amount of N and K. In the plot experiment, turfgrass density was increased by 12.9-19.2% under SMFp treatments compared with the control. These results indicated that the application of SMF containing Sa. cerevisiae HS-1 and St. thermophiles HS-2 improved the quality, density, and growth of creeping bentgrass via prompting the uptake of N and K.

• Journal of the Korean Ceramic Society
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• v.42 no.8 s.279
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• pp.567-574
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• 2005

Densification of SiC powder with additives of total amount of2, 4, 8 $wt\%$ Al-B-C was carried out by Spark Plasma Sintering (SPS). The unique features of the process are the possibilities of a very fast heating rate and a short holding time to obtain fully dense materials. The heating rate and applied pressure were kept at $100^{\circ}C/min$ and 40 MPa, while the sintering temperature and holding time varied from 1700 - $1800^{\circ}C$ for 10 - 40 min, respectively. The SPS-sintered specimens with different amount of Al-B-C at $1800^{\circ}C$ reached near-theoretical density. The $3C{\rightarrow}6H,\;15R{\rightarrow}4H$ phase transformation of SiC was enhanced by increasing the additive amount. The microstructure of SiC sintered up to $1750^{\circ}C$ consisted of fine equiaxed grains. In contrast, the growth of large elongated grains in small matrix grains was shown in sintered bodies at $1800^{\circ}C$, and the plate-like grains interlocking microstructure had been developed by increasing the holding time at $1800^{\circ}C$. The grain growth rate decreases with increasing amount of Al-B-C in SiC starting powder, however, the both of volume fraction and aspect ratio of large grains in sintered body increased.

• Journal of Chest Surgery
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• v.25 no.5
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• pp.469-479
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• 1992

Searching for the clinical effects of colloid solutions that used to increasing the oncotic pressure of priming solutions at the cardiopulmonary bypass, 29 patients [who were diagnosised as simple VSD around 10kg of body weight and scheduled to be operated from June 1990 to December 1990 at Sejong General Hospital] were divided randomly and prospectively to the two groups: A group [15] was received 4gm% albumin as addition to the priming solutions and B Group [14] the same amount of Ringer`s lactated solution. 34 clinical parameters [Body weight, sex, age, body surface area, Qp/Qs, pulmonary arterial pressure, cardiopulmonary bypass time, anesthetic time, intraoperatively infused crystalloid and colloid amount, hemoglobin, hematocrit, serum sodium concentration, serum osmolarity, urine osmolarity, urine specific gravity, serum concentration, serum osmolarity, urine osmolarity, urine specific gravity, serum protein, serum albumin concentration, urine output, central venous pressure, postoperatively infused colloid amount, immedediate post-operative peak inspiratory pressure, cardiac index, blood pressure and pump flow during cardiopulmonary bypass, inotro-pic assist, diuretics, extubation period, total drain amount, duration of ICU] were measured and compaired between the two groups. There were no differences of preoperative and operative clinical parameters. And postoper-atively, practically there were no nearly differences at the clinical outcomes between the two groups, but some parameters [cardiac index, PIP, BP and pumpflow during CPB, etc] contributed to being preferable to the Group A at certain times [P<0.05]. Conclusively, it might be thought that the priming solution of cardiopulmonary bypass added by colloid solution had some beneficial effects on the patients, especially younger and associated with complex anomaly to be expected taken longer time of cardiopulmonary bypass, and more studies about the neonatal and complex anomaly cases were needed in that points.

• Resources Recycling
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• v.25 no.3
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• pp.43-48
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• 2016

Cement manufacturing plant uses various kinds of industrial/municipal waste. The waste contains considerable amount of potassium, chlorine and small amount of heavy metal. Many researches were performed to fabricate valuable resources from the waste. In this study, various methods, which dissolves and crystallizes potassium/chlorine to extract potassium chloride, were experimented. Especially amount of water, slurry temperature, and stirring time were controlled. Then kind of heavy metal and content of potassium chloride were analyzed. The yield of potassium chloride increased, as the amount of water for slurry increased but it increased slightly, when the water content was over 200%. The yield tended to increase, when the temperature of slurry was over a certain point. The yield did not increase in case of over 10 minutes stirring time. The kind and content of heavy metal in potassium chloride were various according to stirring time. The main heavy metals were Pb, Cu, and $Cr^{6+}$.

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.490-497
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• 1991

Kongjaban (a Korean-style seasoned black soybean) prepared under various conditions such as different soaking temperatures and time, cooking rate, and amounts of sugar and soy sauce was investigated with respect to its physical and sensory qualities. Soaking soybeans in water at $20^{\circ}C$ and $60^{\circ}C$ prior to heating decreased the hardness, degree of browning and saltiness of kongjaban, regardless of soaking temperature. As the cooking time after addition of sugar and soy sauce increased, the degree of browning, saltiness and hardness of kongjaban increased markedly. The amount of sugar and soy sauce did not make a distinct difference in its physical properties whereas its hardness increased slightly with increasing sugar amount. According to the sensory evaluation, the color, hardness and saltiness of kongjaban significantly increased with increasing cooking time. Color, hardness and sweetness increased as the amount of sugar increased whereas the amount of soy sauce did not affect the sensory characteristics except for saltiness.

• Journal of Family Resource Management and Policy Review
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• v.16 no.2
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• pp.165-186
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• 2012

Studies on time-use have generally concentrated on the amount of time used by each member of a household in Korea. The quality of family relationships could be associated with the amount and types of interactions between family members. This study examined the time that adults spend with their family members on various activities. The purpose of this study is to explore a typology of family time and investigate the characteristics of each type. The data source was the 2009 Time-Use Survey conducted by the Korean National Statistics Office. The people involved in each activity were surveyed for the first time in the 2009 survey in Korea. The data from this study included 10,902 diaries that were filled on weekdays by married adults from ages 20 to 59 years. Data from rural households were excluded. Time use was divided into three categories: family meals, household work and family leisure time. These activities were analyzed using t-test, chi-square analysis and cluster analysis. Family time was classified into four types based on three categories. The four types were named "leisure sharing", "household work sharing", "overall sharing" and "non-sharing". The most common type was non-sharing. The characteristics of each type depended on gender and paid work time. Based on these results, family and labor policies should be developed to increase the work-life balance. Policies that focus on men over 40 years are especially recommended.