• Journal of the Korean Mathematical Society
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• v.56 no.2
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• pp.421-437
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• 2019

We establish some Hessian comparison theorems and volume comparison theorems for Riemann-Finsler manifolds under various line radial integral curvature bounds. As their applications, we obtain some results on first eigenvalue, Gromov pre-compactness and generalized Myers theorem for Riemann-Finsler manifolds under suitable line radial integral curvature bounds. Our results are new even in the Riemannian case.

• Korean Journal of Child Studies
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• v.38 no.1
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• pp.117-126
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• 2017

Objective: The purpose of this study was to investigate young children's nonsymbolic magnitude comparison ability according to ratio limit and task condition. Methods: The participants included 40 3-year-old children, 42 4-year-old children, and 41 5-year-old children recruited from 4 childcare centers located in Seoul, Korea. All magnitude comparison tasks were composed of image material tasks and concrete material tasks. In addition, each magnitude comparison task varied with the ratio of the two quantities; 0.5 ratio, 0.67 ratio, 0.75 ratio. Results and Conclusion: The results revealed that 3-, 4-, and 5-year-old children could perform nonsymbolic magnitude comparison tasks without learning experiences. Also, 3-, 4-, and 5-year-old children could perform concrete material tasks better than image material tasks in nonsymbolic magnitude comparison tasks. Furthermore, children's performance on nonsymbolic magnitude comparison tasks indicated the ratio signature of the approximate number system. Children have a degree of numerical capacity prior to formal mathematics instruction. Also, children were influenced by task conditions or sense stimulus when they processed numerical information. Furthermore, the approximate number system can be used in understanding the ordinality of number.

• The Journal of Information Systems
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• v.20 no.3
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• pp.41-61
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• 2011

In order to buy products through the Internet, consumers dissipate much time and efforts in collecting and comparing product information from various online shopping malls. Consumers can save their efforts by using price comparison sites, but there are some shortcomings in comparison shopping. Firstly, comparison sites do not show the lowest price of some products that are selling in shopping malls. Secondly, the product information provided by comparison sites is sometimes wrong. Thirdly, there are too many results. In order to overcome the shortcomings, we suggested a comparison shopping system based on RSS by using ontology matching. We used the current RSS standard for syntactic interoperability instead of suggesting new standards. Moreover, we used ontology matching for semantic interoperability to compare product information with different ontologies. The suggested ontology matching consists of three steps. The first step is finding exact sense from WordNet for a given product category, and the second step is searching for matching product category candidates from the products of RSS feeds. The final step is calculating similarities of the candidates with the target product category. From the experiments, we could get better recall rates that are suitable for e-commerce environments and the results show that our system is effective in product comparison.

• Journal of Positioning, Navigation, and Timing
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• v.5 no.2
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• pp.67-74
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• 2016

In this paper, time comparison is performed with standardization institution in Japan using a Two-Way Satellite Time and Frequency Transfer (TWSTFT) technique as one of the methods for high precision time comparison. To analyze the performance of time comparison in the TWSTFT method, time comparison results via the Global Positioning System (GPS) code and carrier wave are analyzed. Through the time comparison performance, frequency stability is analyzed using modified Allan deviation and by this result, characteristics of time comparison of the TWSTFT that is utilized in international time comparison are presented.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.43-48
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• 2005

In order to facilitate technical exchange among nations and/or institutes through the establishment of mutual recognition and the reliability guarantee of testing results by testing standards standardization, the interlaboratory comparison tests on brake discs and linings between KRRI and CARS were conducted. So far, two ways of comparison tests were performed for a better understanding of mutual recognition and standardization in railroad brake linings between Korea and China. In this paper, the first and second comparison testing results have been summarized, and the suggestions for the future research work are also presented to encourage extensive research on comparison study of railroad brake discs and linings between KRRI and CARS. Eventually, the final goal of the current research will be the establishment of standardization of railroad testing standards.

• Journal of Korean society of Dental Hygiene
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• v.19 no.2
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• pp.221-229
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• 2019

Objectives: The purpose of this study was to confirm job satisfaction, job performance, and turnover intention according to dental hygienists' clinical assistance and preventive work. Methods: The collected data (N=380) were analyzed with independent t-tests and Pearson correlations using SPSS Statistics ver. 21.0 (IBM Co., Armonk, NY, USA). Results: The results indicated that the higher the overall job satisfaction of the dental hygienist, the higher their job performance and the lower their turnover intention (p<0.05). The results of the comparison of job satisfaction showed that preventive work was higher than dental hygienists' clinical assistance in all items except "I was pleased with work" (p<0.05). The results of the comparison of job performance showed that preventive work was higher than dental hygienists' clinical assistance in all items except "I have never complained, even if things go wrong" (p<0.05). The results of the comparison of turnover intention showed that clinical assistance was higher than dental hygienists' preventive work in all items (p<0.05). Conclusions: Our results demonstrate that job satisfaction, turnover intentions, and job performance have positive effects for preventive work. Therefore, dental clinics need to improve the actual environment so that dental hygienists can focus on preventive work.

• The Korea Journal of Herbology
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• v.22 no.2
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• pp.83-95
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• 2007

Objectives : The present study had been undertaken to investigate the effects of Korean Corni Fructus(KCF) on treatment of osteoporosis in ovariectomized rats. Method : In this experiment, the rats were ovariectomized. Rats were administered by KCF. The levels of bone mineral density, osteocalcin, ALP, calcium, phosphorus in serum, calcium, phosphorus, deoxypyridinoline in urine, calcium, phosphorus, ash weight of bone, body weight and uterus weight were measured. Results : The levels of femoral and fibula-tibial bone mineral density were significantly increased in comparison with OVX group at 4, 8 weeks in KCF group. The levels of serum osteoclacin showed significant decrease in comparison with OVX group at 4, 8 weeks in KCF group. The levels of serum ALP showed significant decrease in comparison with OVX group at 4 week in KCF group. The levels of serum calcium showed significant increase in comparison with OVX group at 8 week in KCF group. The levels of urine calcium and phosphoruls showed significant decrease in comparison with OVX group in KCF group. The levels of femoral and fibula-tibial calcium didn't show significant changes in comparison with OVX group in KCF group. The levels of femoral and fibula-tibial phosphorus didn't show significant changes in comparison with OVX group in KCF group. The levels of femoral and fibula-tibial ash weight didn't show significant changes in comparison with OVX group in KCF group. The levels of body weight were significantly decreased in comparison with OVX group at 4, 8 weeks in KCF group. The levels of uterus weight were significantly increased in comparison with OVX group in KCF group. Conclusion : Reviewing these experimetal results, it appeared that KCF had efficacy on treatment of osteoporosis.

• Journal of Sensor Science and Technology
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• v.31 no.6
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• pp.448-454
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• 2022

An intralaboratory comparison of the realization of the triple-point temperature of mercury, which is defined as -38.8344℃ on the international temperature scale of 1990 (ITS-90), was conducted at the Korea Research Institute of Standards and Science (KRISS), the national metrology institute of Korea. To this end, four triple-point-of-mercury cells were compared using the resistance ratio measurement of a standard platinum resistance thermometer to validate the calibration results obtained using the triple-point-of-mercury cells at KRISS. The triple-point temperatures of all the four cells, one of which is designated as the national standard cell, were within 0.3 mK of the national standard. Based on 13 experiments on the four triple-point-of-mercury cells, the uncertainty in the comparison of the triple-point-of-mercury cells was 0.08 mK, and the uncertainty in the realization of the triple-point temperature of mercury was 0.19 mK. The results of the intralaboratory comparison validated that utilizing any of the four triple-point-of-mercury cells would result in the realization of a temperature within 0.3 mK of the average value determined by two key international comparisons for the realization of -38.3844℃ following the ITS-90.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.5
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• pp.1476-1484
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• 2004

Aging is characterized by an age-dependent reduction in bone density. Pronounced bone loss by postmenopausal estrogen deficiency induces a bad effect on dynamic balance of bone metabolism. When the bone density is reduced to the level below the fracture threshold, the risk for fracture is greatly increased. The purpose of this study is to examine what are the effects of the Guisinhwan(GSH : 歸腎丸) on the ovariectomized rat model of postmenopausal osteoporosis. The results of the experiment are as follows: Body weight in control group showed significant increase in comparison with sham, but that in GSH-treated showed no change in comparison with control. The level of serum albumin in control group showed significant decrease in comparison with sham. That in GSH-treated was slightly decreased in comparison with control. The level of serum ALP activity in control group showed significant increase in comparison with sham, but that in GSH-treated was significantly decreased in comparison with control. The level of serum phosphorous, calcium, GOT, GPT, T3 did not significant change among the three groups. The level of serum estrogen in control group showed slightly decreased in comparison with sham, but that in GSH-treated showed no change in comparison with control. The level of serum T4 in control group showed significant increase in comparison with sham, but that in GSH-treated was significantly decreased in comparison with control. Trabecular bone area as well as trabecular thickness in control group showed significant decrease In comparison with sham. Those in GSH-treated showed significant increase in comparison with control. Trabecular number did not significant change among the three groups. Trabecular separation only in GSH-treated showed significant decrease in comparison with control. Osteoclast number in control group showed significant increase in comparison with sham. That in GSH-treated showed significant decrease in comparison with control. Oseoblast surface in control group showed significant increase in comparison with sham, but that in GSH-treated showed no change in comparison with control. According to the above these results, GSH has shown to be capable of preventing and curing osteoporosis caused by old-aged and postmenopause.

• Bulletin of the Korean Mathematical Society
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• v.60 no.2
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• pp.495-505
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• 2023

In this note, we study a comparison principle for elliptic obstacle problems of p-Laplacian type with L¹-data. As a consequence, we improve some known regularity results for obstacle problems with zero Dirichlet boundary conditions.