• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.260-267
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• 2010

As sloped farmland is subject to runoff and soil erosion and consequently require appropriate vegetative coverage to conserve soil and water, a field study was carried out to evaluate the impact of crop canopy coverage on soil loss and runoff from the experimental plot with three different textural types (clay loam, loam, and sandy loam). The runoff and soil loss were examined at lysimeters with 15% slope, 5 m in length, and 2 m in width for five months from May to September 2009 in Suwon ($37^{\circ}$ 16' 42.67" N, $126^{\circ}$ 59' 0.11" E). Red pepper (Capsicum annum L. cv. Daechon) seedlings were transplanted on three different dates, May 4 (RP1), 15 (RP2), and 25 (RP3) to check vegetation coverage. During the experimental period, the vegetation coverage and plant height were measured at 7 day-intervals and then the 'canopy cover subfactor' (an inverse of vegetation cover) was subsequently calculated. After each rainfall ceased, the amounts of soil loss and runoff were measured from each plot. Under rainfall events >100 mm, both soil loss and runoff ratio increased with increasing canopy cover subfactor ($R^2$=0.35, p<0.01, $R^2$=0.09, p<0.1), indicating that as vegetation cover increases, the amount of soil loss and runoff reduces. However, the soil loss and runoff were depending on the soil texture and rainfall intensity (i. e., $EI_{30}$). The red pepper canopy cover subfactor was more highly correlated with soil loss in clay loam ($R^2$=0.83, p<0.001) than in sandy loam ($R^2$=0.48, p<0.05) and loam ($R^2$=0.43, p<0.1) plots. However, the runoff ratio was effectively mitigated by the canopy coverage under the rainfall only with $EI_{30}$<1000 MJ mm $ha^{-1}hr^{-1}$ ($R^2$=0.34, p<0.05). Therefore, this result suggested that soil loss from the red pepper field could be reduced by adjusting seedling transplanting dates, but it was also affected by the various soil textures and $EI_{30}$.

• Tunnel and Underground Space
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• v.27 no.1
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• pp.50-57
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• 2017

In this study, the experiment for determining shock loss at the branch is conducted for the design of network double-deck road tunnel ventilation. The shock loss coefficient that determines the quantity of shock loss has been considered only regarding the constant aspect ratio of circular or rectangular section. However the suggestion of shock loss coefficient is needed since the aspect ratio of double-deck road tunnel for small vehicle is considered around 1:3 with the low height in Korea. The experiment model was made with the scale of around 1:23 applying Reynolds similarity law, so that the shock loss coefficient on the branch of the large aspect ratio was measured. The result of the study showed that shock loss coefficients of both split branch and straight branch were measured two to three times higher than those calculated from the theoretical equation or design values of previous studies. Therefore the study resulted the effect of large aspect ratio on shock loss coefficient was huge, and it is expected that precise design value can be suggested for the design of network double-deck tunnel ventilation.

• Journal of Advanced Navigation Technology
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• v.17 no.5
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• pp.516-523
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• 2013

In this paper, The path loss model of Air Traffic Control(ATC) telecommunication radio channel has been studied at the Incheon International Airport(IIA) with the terminal with two antlers. We measured two frequencies among VHF/UHF channel bands. The transmitting site radiated the Continuous Wave(CW). The propagation measurement was taken using the moving vehicle equipped with receiver and antenna. The transmitting power, frequency and antenna height are the same as the current operating condition. The path loss exponent and intercept parameters were extracted by the basic path loss model and hata model. The path loss exponents at passager terminal areas were 3.32 and 3.10 respectively in 128.2 MHz and 269.1 MHz. The deviation of prediction error is 9.69 and 9.65. The new path loss equation at the terminal area was also developed using the derived path loss parameters. The new path loss was compared with other models. This result will be helpful for the ATC site selection and service quality evaluation.

• Clinical and Experimental Pediatrics
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• v.49 no.3
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• pp.292-297
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• 2006

Purpose : In medulloblastoma, craniospinal radiation therapy combined with chemotherapy improves the prognosis of tumors but results in significant endocrine morbidities. We studied the endocrine morbidity, especially growth pattern changes. Methods : The medical records of 37 patients with medulloblastoma were reviewed retrospectively for evaluation of endocrine function and growth. We performed the growth hormone stimulation test in 16 patients whose growth velocity was lower than 4 cm/yr. Results : The height loss was progressive in most patients. The height standard deviation score (SDS) decreased from $-0.1{\pm}1.3$ initially to $-0.6{\pm}1.0$ after 1 year(P<0.01). Growth hormone deficiency(GHD) developed in 14 patients. During the 2 years of growth hormone(GH) treatment, the improvements of height gain or progressions of height loss were not observed. Twelve patients(32.4 percent) revealed primary hypothyroidism. One of six patients diagnosed with compensated hypothyroidism progressed to primary hypothyroidism. Primary and hypergonadotropic hypogonadism were observed in two and one patients respectively. There was no proven case of central adrenal insufficiency. Conclusion : Growth impairment developed frequently, irrespective of the presence of GHD in childhood survivors of medulloblastoma. GH treatment may prevent further loss of height. The impairment of the hypothalamic-pituitary-gonadal and hypothalamic-pituitary-thyroidal axis is less common, while central adrenal insufficiency was not observed.

• The Korean Journal of Food And Nutrition
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• v.22 no.2
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• pp.286-292
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• 2009

This study was conducted to examine the effects of an 8-week weight loss program, on body composition, body shape satisfaction, body shape esteem in 15 obese children. This program included nutritional education and regular physical fitness. After completion of this program, height and body weight increased slightly but body compositions changed. BMI, degree of obesity, and body fat levels dropped slightly, however these differences were not significant. After the 8-week program body weight increased from $63.61{\pm}8.80\;kg$ to $64.07{\pm}9.11\;kg$, degree of obesity and BMI decreased from $151.73{\pm}13.62%$, and $29.08{\pm}2.35$ to $146.60{\pm}12.92%$, and $28.57{\pm}2.26$, respectively, and the percentage of body fat decreased slightly from $42.70{\pm}4.87%$ to $41.46{\pm}4.88%$. There were slight changes in weight of body muscle and lean body mass from $19.62{\pm}3.48\;kg$ and $36.17{\pm}5.78\;kg$ to $20.30{\pm}3.64\;kg$ and $37.16{\pm}6.18\;kg$, respectively. LBM and amount of muscle were higher after this weight loss program. The body shape esteem score increased from $7.60{\pm}4.01$ to $9.00{\pm}6.20$. There was no significant difference in body shape satisfaction before and after the program, and the participants also wanted to be leaner. Finally, body weight, BMI, and body fat showed negative correlations to body shape esteem.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.3
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• pp.194-198
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• 2010

Recently as the electronic devices are getting to be more and more smaller, transformers are needed to be micro fabricated using MEMS technology. In this paper transformers have been fabricated and measured by depositing insulation layer to reduce the loss of eddy current and in the middle core a high permeability permalloy was designed based on the turns ratio between primary coil and secondary coil which are 1:1 transformers. (the number of turns of primary coil and secondary coil: 3/3, 5/5, 7/7). The size of the transformers including ground shield are $1mm{\times}1.5mm$, $1mm{\times}1.95mm$, $1mm{\times}2.35mm$ respectively. The line width, pitch and the height of post are 50um. Based on the measured data from the micro fabricated transformers, the 3/3 turns in the primary coil and secondary coil showed the lowest insertion loss with 1.5 dB at 480 MHz and the 7/7 turns in the primary coil and secondary coil showed the highest insertion loss with 2.5 dB at 280 MHz. Also confirmed that the bandwidth goes up as the number of turns goes down. There was some difference between the actual measured data and the HFSS simulation result. It looks as if it is an error of the difference between oxidation of copper or the permeability of SU-8.

• Korean Journal of Community Nutrition
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• v.18 no.6
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• pp.599-610
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• 2013

This study was carried out to analyze the effect of a diet program for adult women on weight loss, BMI, eating habits, sleeping habits, health related indices. The subjects was 415 participants of the 10 weeks (20 time participation program). The data was collected by basic somatometry and HRV (Heart Rate Variability) / APG (Accelerated Plethysmograph) Analyzer. The average age, height, weight and BMI were 28.6 years, 162.1 cm, 62.8 kg and 23.9 $kg/m^2$, respectively. Their body types by BMI were under weight (1.2%), normal (45.8%), overweight (24.8%), mild obesity (22.7%) and obesity (5.5%). There were significant reductions of average weight (4.6 kg) and average BMI (1.75 $kg/m^2$) on the 10th week. There were positive changes in vascular age (50.4%), stress index (44.6%), fatigue index (43.9%), health index (54.5%) of the subjects during the program. There was a meaningful difference of the average variation for the vascular age, stress index, fatigue index, and health index between two groups; one improving the eating habit and the other did not (p<0.05), and also there was a meaningful difference of the average variation for the fatigue index in both groups improving the sleeping habit (p<0.05), but was not a meaningful difference of the average variation for the vascular age, stress index, and health index between two groups. There was a meaningful difference of the average variation for the vascular age, stress index, fatigue index, and health index between two groups improving both eating and sleeping habit (p<0.05). In conclusion, the weight loss program was effective on the weight loss and BMI reduction and health related indices.

• Journal of the Korean Solar Energy Society
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• v.27 no.4
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• pp.121-128
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• 2007

Convective heat loss from solar tower receiver is experimentally investigated in wind tunnel with tilt angles and operating conditions. In order to simulate the receiver, an electric heater, which is made of aluminum (width : 100 mm, height : 100mm) is used and installed in the wind tunnel. The convective heat loss from the receiver is dependent on the direction and the velocity of the wind and the surface temperature of the receiver. The tilt angle and surface temperature of the receiver are varied from 0o (cavity facing straight down) and 90o(cavity aligned horizontally) and from $150^{\circ}C$ to $250^{\circ}C$, respectively. Also, the wind speed is changed from 0 to 4m/s. The convective heat loss is obtained by measuring consumed power to the heater to maintain the desired surface temperature. It is concluded that Nusselt number increases with increasing wind speed for all cases. Especially, it is showed that Nusselt number can be maximized when the tilt angle is 30o.

• Journal of Periodontal and Implant Science
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• v.49 no.3
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• pp.185-192
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• 2019

Purpose: Implant wall thickness and the height of the implant-abutment interface are known as factors that affect the distribution of stress on the marginal bone around the implant. The goal of this study was to evaluate the long-term effects of supracrestal implant placement and implant wall thickness on maintenance of the marginal bone level. Methods: In this retrospective study, 101 patients with a single implant were divided into the following 4 groups according to the thickness of the implant wall and the initial implant placement level immediately after surgery: 0.75 mm wall thickness, epicrestal position; 0.95 mm wall thickness, epicrestal position; 0.75 mm wall thickness, supracrestal position; 0.95 mm wall thickness, supracrestal position. The marginal bone level change was assessed 1 day after implant placement, immediately after functional loading, and 1 to 5 years after prosthesis delivery. To compare the marginal bone level change, repeated-measures analysis of variance was used to evaluate the statistical significance of differences within groups and between groups over time. Pearson correlation coefficients were also calculated to analyze the correlation between implant placement level and bone loss. Results: Statistically significant differences in bone loss among the 4 groups (P<0.01) and within each group over time (P<0.01) were observed. There was no significant difference between the groups with a wall thickness of 0.75 mm and 0.95 mm. In a multiple comparison, the groups with a supracrestal placement level showed greater bone loss than the epicrestal placement groups. In addition, a significant correlation between implant placement level and marginal bone loss was observed. Conclusions: The degree of bone resorption was significantly higher for implants with a supracrestal placement compared to those with an epicrestal placement.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup2
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• pp.300-308
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• 2001

Objectives : Anterior cervical discectomy and interbody fusion has become a well-accepted surgical treatment of degenerative cervical diseases. Implatable cages have a stabilizing effect without plates and no need for autogenous bone graft. The authors evaluates the effect of implatable titanium cage(RABEA) on the clinical and radiological outcomes. Methods : 34 patients with symptomatic cervical degenerative diseases due to one level disc pathology were underwent anterior cervical discectomy and interbody fusion with titanium cages(RABEA) which were not filled with cancallous bone grafts from January 1999 to May 2001. Patients with osteoporosis and older than 65 years were not included. Among them, 15 patients could be followed-up for at least 1 year. The authors retrospectively reviewed the charts and radiographic data. Mean follow-up period was $1.3{\pm}0.2years$. Results : Clinical results according to the Odom's criteria was exellent and good in 14(93%) patients. One patient with fair result showed complete loss of the disc space height due to settlement of the cage. Preoperatively, the mean height of the disc space(${\pm}$standard deviation) was $3.42{\pm}1.10mm$(range 2.0-5.5mm), and at 1 day postoperatively it was $7.88{\pm}0.90mm$(range 6.50-9.0). The mean height of the disc space after 1 year was $6.50{\pm}1.38mm$(range 3.0-8.0). The restoration of the height was statistically significant(p<0.05). The mean height after 1 year was $82.7{\pm}15.9%$ of the height at 1 day postoperatively. Preoperatively the mean value of the cervical lodortic angle was $21.8{\pm}11.8^{\circ}$ and 1 year postopertively, it was $24.5{\pm}8.3^{\circ}$, which was statistically not significant. All patients showed no abnormal movements on flexion and extension lateral film after 6 months. Conclusion : Implantable titanium cages appear safe and effective in selected patients, and their use helps to avoid complications associated with bone graft harvest. Subsidence of the cage seems to be a potential risk factor for recurrence of the symptoms. For long-term results, a longer follow-up is required.