• Korean Journal of Soil Science and Fertilizer
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• v.36 no.6
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• pp.407-416
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• 2003

Although the requirement and optimum soil level of Si for oriental melon are still not well understood, silicate fertilizer is commonly applied to the oriental melon in plastic film houses where soil silicate level is relatively high. In this research the effects of silicate fertilizer on growth, fruit yield and fruit quality of oriental melon, and soil properties were investigated in plastic film house where the soil available silicate was $212mg\;SiO_2\;kg^{-1}$. Silicate fertilizer was applied in the rates of 100, 200, and $300kg\;10a^{-1}$. The application of silicate fertilizer could not increase the early growth of oriental melon, and also the fruit yield and quality were not different among the treatments. Available Si and P contents in soils and also Si and P contents in leaf of oriental melon of the different treatments were not significantly different. In the relationship between total Si in oriental melon leaf and soil silicate extracted by 1 N sodium acetate, optimum soil available silicate level for oriental melon was found to be around $100mg\;SiO_2\;kg^{-1}$. These results indicate that the additional silicate fertilization in soils of available silicate higher than $100mg\;SiO_2\;kg^{-1}$ is unnecessary, and such application of silicate can not have any beneficial effect on the growth and fruit yield of oriental melon.

• Analytical Science and Technology
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• v.24 no.3
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• pp.200-211
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• 2011

In this study, 13 compounds including four volatile fatty acids (VFA) and nine volatile organic compounds (VOC) were analyzed by cryogenic trapping-thermal desorption technique. In order to evaluate the analytical method for VFA, calibration experiments were performed using five different sorbent materials. When the calibration results are compared between different sorbents, sampling tube filled with Carbopack X showed the highest response factor (RF) for both VFA and VOC. To validate this new analytical method for VFA using cryogenic trapping-thermal desorption technique, this method was compared with alkali absorption method recommended by the odor prevention law of the Korea Ministry of Environment (KMOE). For this purpose, unknown samples were analyzed by two different methods, i.e., cryogenic trapping-thermal desorption (TD) and alkali absorption with solid phase microextraction (SPME). When the results of two different methods were compared, ratios of concentrations determined by the two analytical methods (TD/SPME) was found as 0.46 (valeric acid) ~ 0.71 (isovaleric acid). Therefore, additional study is required to properly establish and find stable analytical conditions for VFA analysis. Furthermore, comparison between two different methods should be made with more reliable calibration approaches.

• Journal of the Korean Society of Radiology
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• v.15 no.3
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• pp.321-327
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• 2021

Wrist PA-grip view is used to diagnose triangular fibrocartilage complex (TFCC) tear because it can easily diagnose damage to the surrounding wrist ligaments. However, despite advances in radiology equipment, distortion of images due to geometric elements still has many limitations. In this paper, we propose a method that can minimize the distortions of images by analyzing the distortions occurring in the wrist PA-grip view. A source of image distance (SID) were set at 130 cm and 150 cm for comparison with 110 cm. Depending on the SID, the phantom of wrist was moved at 0, 2, 4, 6, 8, and 10 cm in the X-axis and Y-axis directions, respectively. For quantitative evaluation, the difference of distance between the radius and ulna was measured in picture archiving and communication system (PACS) system. As a qualitative evaluation, survey was conducted among 20 radiologic technologists who examined the Wrist PA-grip view. The Kruskal Wallis test was performed to compare the distortion according to the phantom movement in the X-axis and Y-axis directions based on the SID, and the Tukey test was performed as a post-test. In the quantitative evaluation results, the measured values obtained in the X-axis was not significantly different in all groups (p>0.05). The measured values obtained in the Y-axis was significantly different in the most groups (p<0.05). Therefore, to reduce distortion while maintaining image quality, we recommend what examine the SID at 150 cm than 110 cm.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.1
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• pp.38-48
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• 2011

Purpose: Dentists suffer back, neck and shoulder pain during their careers due to bad operating posture. If dentists have a good operating posture ergonomically, there would be less pain and discomfort in the shoulder and back. Therefore, dentists should learn the Home position which enables dentists to approach a stable posture ergonomically. This study was to compare tooth preparation in the Home position and the Random position, and evaluate the clinical efficacy of the Home position. Materials and methods: Tooth preparation for fixed partial denture was performed on the maxillary left 2nd premolar and maxillary left 2nd molar at the two different operating positions were compared. The amount of occlusal reduction, marginal width, subgingival margin depth, and convergence angle were measured. A T-test was performed separately to compare the results of the Random position and the Home position. Results: 1. The amounts of average thickness of occlusal reduction on fossa were deficient to the ordered ones in the Random position and the Home position (P > .05). 2. The average subgingival margin depth of prepared margin on maxillary left 2nd premolar, maxillary left 2nd molar were excessive in the Random position than in the Home position. On the maxillary left 2nd premolar, there was no statistical difference in the Random position and the Home position except Distal midline, DL line angle, Lingual midline, ML line angle (P< .05). On the maxillary left 2nd molar, there was no statistical difference in the Random position and the Home position (P < .05). 3. Average convergence angle in the Random position and the Home position were excessive compared to the ordered angle. There was no statistical difference in the Random position and the Home position (P > .05). 4. Analysis of pearson correlation : In the Random position, the amounts of average thickness of occlusal reduction, the average subgingival margin depth of prepared margin, convergence angle were significantly associated with each other (P < .05). But in the Home position, they were not significantly associated with each other (P < .05). 5. The time needed for preparation in the Home position was faster or equal than that of the Random position as time went on. Conclusion: In conclusion, there were no significant differences between Home position and Random position in measures of occlusal reduction, marginal width, marginal depth, convergence angle. However, preparation time and incidence of damaging adjacent teeth were less in Home position than in Random position. Therefore, if trained properly, Home position which is more ergonomically stable can be adopted for clinical use.

• Journal of Intelligence and Information Systems
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• v.20 no.4
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• pp.107-120
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• 2014

This study proposes a novel recommender system using the structural hole analysis to reflect qualitative and emotional information in recommendation process. Although collaborative filtering (CF) is known as the most popular recommendation algorithm, it has some limitations including scalability and sparsity problems. The scalability problem arises when the volume of users and items become quite large. It means that CF cannot scale up due to large computation time for finding neighbors from the user-item matrix as the number of users and items increases in real-world e-commerce sites. Sparsity is a common problem of most recommender systems due to the fact that users generally evaluate only a small portion of the whole items. In addition, the cold-start problem is the special case of the sparsity problem when users or items newly added to the system with no ratings at all. When the user's preference evaluation data is sparse, two users or items are unlikely to have common ratings, and finally, CF will predict ratings using a very limited number of similar users. Moreover, it may produces biased recommendations because similarity weights may be estimated using only a small portion of rating data. In this study, we suggest a novel limitation of the conventional CF. The limitation is that CF does not consider qualitative and emotional information about users in the recommendation process because it only utilizes user's preference scores of the user-item matrix. To address this novel limitation, this study proposes cluster-indexing CF model with the structural hole analysis for recommendations. In general, the structural hole means a location which connects two separate actors without any redundant connections in the network. The actor who occupies the structural hole can easily access to non-redundant, various and fresh information. Therefore, the actor who occupies the structural hole may be a important person in the focal network and he or she may be the representative person in the focal subgroup in the network. Thus, his or her characteristics may represent the general characteristics of the users in the focal subgroup. In this sense, we can distinguish friends and strangers of the focal user utilizing the structural hole analysis. This study uses the structural hole analysis to select structural holes in subgroups as an initial seeds for a cluster analysis. First, we gather data about users' preference ratings for items and their social network information. For gathering research data, we develop a data collection system. Then, we perform structural hole analysis and find structural holes of social network. Next, we use these structural holes as cluster centroids for the clustering algorithm. Finally, this study makes recommendations using CF within user's cluster, and compare the recommendation performances of comparative models. For implementing experiments of the proposed model, we composite the experimental results from two experiments. The first experiment is the structural hole analysis. For the first one, this study employs a software package for the analysis of social network data - UCINET version 6. The second one is for performing modified clustering, and CF using the result of the cluster analysis. We develop an experimental system using VBA (Visual Basic for Application) of Microsoft Excel 2007 for the second one. This study designs to analyzing clustering based on a novel similarity measure - Pearson correlation between user preference rating vectors for the modified clustering experiment. In addition, this study uses 'all-but-one' approach for the CF experiment. In order to validate the effectiveness of our proposed model, we apply three comparative types of CF models to the same dataset. The experimental results show that the proposed model outperforms the other comparative models. In especial, the proposed model significantly performs better than two comparative modes with the cluster analysis from the statistical significance test. However, the difference between the proposed model and the naive model does not have statistical significance.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.3
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• pp.427-432
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• 2009

The aim of this study was to compare the shear-peel strength and the fracture site of 5 commercially available orthodontic band cements. One hundred molar bands were cemented to extracted human 3rd molars. The specimens were prepared in accordance with the manufacturer's instructions for each cement. After storage in a humidor at $37^{\circ}C$ for 24 hours, the shear debonding force was assessed for each specimen using an universal testing machine with crosshead speed of 2 mm/minute. Maximal failure stress was converted to mean shear-peel strength, MPa. The predominant site of band failure was recorded visually for all specimens as either at the band/cement or cement/enamel interface. Mean shear-peel strength of Ormco was the highest(2.44${\pm}$0.57), followed by Fuji $Ortho^{TM}$(2.24${\pm}$0.50), $Ketac-Cem^{TM}$(2.10${\pm}$0.57), 3M $Unitek^{TM}$(1.82${\pm}$0.43), $Band-Lok^{TM}$(1.73${\pm}$0.28). There were statistically significant differences between Ormco and $Band-Lok^{TM}$, Ormco and 3M $Unitek^{TM}$, and Fuji $Ortho^{TM}$ and $Band-Lok^{TM}$(p<0.05). The predominant site of bonding failure for bands cemented with the Ormco was at the band/cement interface, whereas bands cemented with Ultra $Band-Lok^{TM}$ failed predominantly at the enamel/cement interface. There was no significant difference among the other cements(Fuji $Ortho^{TM}$, 3M $Unitek^{TM}$, $Ketac-Cem^{TM}$).

• Clinical and Experimental Pediatrics
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• v.51 no.6
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• pp.634-639
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• 2008

Purpose : There has been considerable disagreement regarding the most appropriate dosage of gonadotropin-releasing hormone agonist in cases of central precocious puberty. The aim of this study was to determine the appropriate dosage for suppression of the puberty in girls with central precocious or early puberty. Methods : Twenty-two girls with early puberty were randomly subjected to 3 types of dosages of leuprolide acetate for at least 6 months. The number of cases in groups 1, 2, and 3 were 7, 7, and 8, and dosages were 70, 90, and $110{\mu}g/kg/-month$, respectively. Height, weight, bone age, Tanner stage of breast development, and serum levels of LH, FSH, estradiol, and progesterone were measured before treatment and after 6 months of treatment. The number of cases of puberty suppression was compared using a modified puberty suppression score with a nonparametric chi-square test. Results : There were no significant differences of chronologic and bone ages among the groups. There was a significant decrease in height SDS gain after 6 months in group 3 (P<0.05) compared with groups 1 and 2. Serum levels of LH, FSH, estradiol and progesterone were all significantly decreased after treatment in all 3 groups (P<0.05). The number of cases of puberty suppression in each group were 4 (57%), 5 (71%), and 8 (100%). There was a significantly increased proportion of suppression of puberty in group 3 (P<0.05). Conclusion : It was necessary to use a higher dose of gonadotropin-releasing hormone agonist to suppress early puberty in girls; however further longitudinal study will be needed for their prognosis of final adult height.

• Journal of Animal Science and Technology
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• v.49 no.3
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• pp.321-328
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• 2007

Two pig trials were conducted to test Herb MixⓇ, a mixture of Rehmannia glutinosa, Angelica gigas, Discorea japonica, Glycyrrhiza uralensis, Schisandra chinensis and Ligusticum jeholense, as a herbal additive to weaning pig diet. Exp. 1 was conducted with 45 three-way cross-bred(Y×L×D) weaning pigs randomly allocated to 3 treatments; control, Herb MixⓇ 0.15% and Herb MixⓇ Gold(Plellidendron amurense fortified Herb MixⓇ) 0.15%. Exp. 2 was conducted with 48 weaning pigs randomly allocated to 4 treatments; control, 0.1%, 0.2% and 0.3% Herb MixⓇ. There was a significant(p=0.05) difference between the control and herbal additive groups, however, no significant difference was found between Herb MixⓇ and Herb MixⓇ Gold in growth performance of Exp. 1. In Ex. 2, supplementation of Herb MixⓇ at all level(0.1%, 0.2% and 0.3%) significantly(P<0.05) improved average daily gain and feed intake, however, there were no significant differences among supplemented groups. Among the blood parameters, serum IgG level and WBC numbers were significantly lowered by Herb Mix supplementation in both experiments. Stress indicator(SI) was significantly lower in herbal additive groups in Exp. 1. Nutrient digestibility of DM and NFE in supplemented groups was lower than the control in Exp. 1. Howener, it was not significantly different among treatments in Exp. 2. Number(cfu) of fecal E.coli decreased while that of Lactobacilli increased in treated groups. It was concluded that fortifying Herb MixⓇ with Plellidendron amurense was not effective in improving the efficacy of Herb MixⓇ and supplementation of Herb MixⓇ at 0.1~0.2% level improves growth performance of weaning pigs. Blood parameters especially immunity related ones(IgG, WBC and SI) were significantly influenced.

• Asian Journal of Turfgrass Science
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• v.22 no.2
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• pp.217-223
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• 2008

This study was conducted to figure out the effect of silicate as growth stimulator on growth of 'Pencrosss' creeping bentgrass. Creeping bentgrass(Agrostis palustris cv. 'Pencross') at the nursery of Sinwon Country Club was used. Silicate was applied at the concentration of 0, $200{\times}$, $500{\times}$, $1.000{\times}$. Polt size was 1 by 2 meter and there were three replications with completely randomized design(CRD). Creeping bentgrass growth was evaluated with visual turf grass quality, root length and No. of tiller density(ea/$cm^2$). Results of this study are as followings; 1. Average root length with silicate was $1.5{\sim}1.9cm$ longer than control. Especially, Root length of silicate was $7{\sim}8cm$ in summer. 2. Tiller density with silicate was $l8{\sim}22ea/cm^2$, $0.4{\sim}2.l$ less than control. But there was no significant difference. 3. Visual turfgrass quality with silicate was $5.0{\sim}8.3$, $0.3{\sim}1.5$ higher than control. But there was no significant difference. In conclusion, silicate might be grown as root growth stimulator of creeping bentgrass during summer in Korea. However, this study was conducted under one year. Accordingly, in-depth experiment should be done over several years.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.12
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• pp.1560-1567
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• 2008

This study was designed to evaluate the effect of green tea products (GTP) on bone metabolism marker in ovariectomized (OVX) rats fed high cholesterol diet. Forty Sprague-Dawley female rats, 10 weeks of age ($279{\pm}2g$), were divided into 4 groups and fed on the experimental diets for 6 weeks: sham operated control (Sham-C) and OVX-control (OVX-C) groups treated high cholesterol diet. OVX-GTP 5% (OVX-G5) and OVX-GTP 20% (OVX-G20) groups were treated with high cholesterol diet containing 5% GTP and 20% GTP, respectively. Food efficient ratio was significantly (p<0.05) lower in OVX-G20 than in the other OVX groups. Bone mineral density of femur was not significantly different among the experimental groups in the order of Sham-C>OVX-G5 and OVX-G20>OVX-C. Alkaline phosphatase activities on serum was lower in the GTP supplement groups than in the OVX-C. Estradiol levels of serum were higher in the GTP supplement groups than in the OVX-C. Osteocalcin levels of serum was the lowest in the OVX-G20. Deoxypyridinoline crosslink values of urine, indicator of bone absorption, was the lowest in the OVX-G20 group. The GTP supplemented groups had a lower bone resorption ratio than in the OVX-C group. From the above results, these findings suggest the possibility of using GTP as a functional food materials related to bone metabolism in menopause.