• Journal of Elementary Mathematics Education in Korea
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• v.14 no.3
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• pp.723-744
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• 2010

The aim of this study was to find the effects of open-ended problems on mathematical creativity and brain function. In this study, one class of first grade students were allocated randomly into two groups. Each group solved different problems. The experimental group solved the open-ended problems and the comparison group solved the closed-problems. Mathematical creativity was tested by the paper test. And Brain function was tested by an EEG(electroencephalogram) tester. The results of this study are as follows. Firstly, this study analyzed how the open-ended problems are effective on mathematical creativity. This analysis showed that it had a meaningful influence on the mathematical creativity(p=0.46). Accordingly, we could find out that open-ended problems make the student connect the mathematical concept and idea and think variously. Secondly, this study analyzed the effect of open-ended problems on brain function. This analysis showed that it did not have a meaningful influence on the brain function(p=.073) statistically but the experimental group's evaluation was higher than comparison groups' at the post-test. It also had a meaningful influence on the brain attention quotient(left) (p=.007), attention quotient(right) (p=.023) and emotion tendency quotient(p=.025). As a result of such tests, we could find out that open-ended problems are effective on brain function, especially on the attention ability. With the use of the open-ended problems, students could show quick understanding and response. An emotion tendency is also developed in the process. Because various answers are accepted, the students gain an internal reward at the process of finding an answer. Putting the above results together, we could find that open-ended problem is effective on mathematical creativity and brain function.

• Journal of the Korean Geotechnical Society
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• v.31 no.3
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• pp.5-16
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• 2015

The characteristics of tensile strength of fiber-reinforced grouting (cement paste) injected into rocks or soils were studied. A tensile strength of such materials utilized in civil engineering has been commonly tested by an indirect splitting tensile test (Brazilian test). In this study, a direct tensile testing method was developed with built-in cylinder inside a cylindrical specimen with 15 cm in diameter and 30 cm in height. The testing specimen was prepared with 0%, 0.5%, or 1% (by weight) of a PVA or steel fiber reinforced mortar. A specimen with 5 cm in diameter and 10 cm in height was also prepared and tested for the splitting tensile test. Each specimen was air cured for 7 days or 28 days before testing. The tensile strength of built-in cylinder test showed 96%-290% higher than that of splitting tensile test. The 3D finite element analyses on these tensile tests showed that the tensile strength from built-in cylinder test had was 3 times higher than that of splitting tensile test. It is similar to experimental result. As an amount of fiber increased from 0% to 1%, its tensile strength increased by 119%-190% or 23%-131% for 7 days or 28 days-cured specimens, respectively. As a curing period increased from 7 days to 28 days, its strength decreased. Most specimens reinforced with PVA fiber showed tensile strength 14%-38% higher than that of steel fiber reinforced specimens.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.2
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• pp.169-178
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• 2010

Objective. This study was conducted to observe the effect on appendage muscle strength according to increase in occlusal vertical dimension. Materials and methods. Ten males with a mean age of 21 were selected. The tested occlusal splints were made at the position of increased occlusal vertical dimension of 2mm,3.5mm and 5mm from the intercuspal position. Before and after wearing occlusal splints, the appendage muscle strength were tested by Cybex II dynamometer (Lumex Inc., Ronkonkoma, NY, USA). Results. Statistical analysis using the paired t-test revealed significant differences for flexion and extension of the hip, pronation of the forearm, internal rotation of the shoulder, external and internal rotation of the knee, and dorsiflexion and plantarflexion of the ankle (p<0.05). Conclusions. As the result of this study, we conclude that when occlusal vertical dimension was increased, most of mean muscular strength values were increased. Especially at the position of 3.5mm increased vertical dimension displayed the highest mean muscular strength value than other positions.

• Tuberculosis and Respiratory Diseases
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• v.68 no.6
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• pp.328-333
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• 2010

Background: There are several active tuberculosis (TB) cases in Korean high schools each school year. The risk of transmission in schools is extremely high due to the considerable time spent in closed classrooms. We evaluated the control of latent tuberculosis infection in Korean high schools. Methods: When a student was identified with active TB, tuberculin skin testing was performed on their classmates and on students in their same school grade. When a student had a positive tuberculin skin tests (TST), they underwent follow-up testing with QuantiFERON-TB Gold In-Tube (QFT). The manufacturer recommended a cut-off of 0.35 IU/mL to determine QFT positivity was applied. Results: A total of 131 pulmonary tuberculosis (TB) patients were included based on the criteria for screening TB contacts in the National Tuberculosis Control Program. Seventy-five (57.2%) students tested smear positive. TST were performed on 7,109 students who were classmates of, or in the same grade as, a TB patient. Of the contacts, 1,231 students (17.3%) were TST positive and they were screened with QFT. Six hundred-sixty-six (55.0%) of the tested students returned a positive QFT result and the rate of positivity was significantly associated with the increasing size of TST indurations (p<0.0001). Conclusion: The use of QFT resulted in approximately 45% of TST positive students not being given chemoprophylaxis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.10
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• pp.1089-1097
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• 2002

In this paper, the novel shipboard Active Phased Array Antenna(APAA) system for maritime mobile satellite communications is introduced. The antenna uses novel technologies like wide range hybrid tracking, single antenna elements with both of Rx and Tx, asymmetrical array structure, interference isolation between Rx and Tx, and error correction method from frequency scan effect. The antenna has single aperture for both of Rx and Tx with 32 $\times$ 4 two-dimensional array. The antenna has two beams. Its frequencies are 7.25 ~ 7.75 GHz for Rx and 7.9 ~ 8.4 GHz for Tx. The antenna gains are 35.4 dBi for Rx and 35.7 dBi for Tx, those are 54 % of efficiency. The electrically steering ranges are $\pm$35$^{\circ}$ of elevation direction and $\pm$4$^{\circ}$ of azimuth direction. The mechanical control ranges at hybrid tracking capability are continuous 360$^{\circ}$ of azimuth direction and $\pm$10$^{\circ}$ of elevation direction. The antenna has 2.2$^{\circ}$ of 3 dB beamwidth, -14 dB of sidelobe level, and 21 dB of cross-pol suppression. The antenna performance was measured by near field measurement set. Its system performance was tested on the ship motion simulator and with the satellite transponder simulator. The test result showed that its tracking error was within -3 dB from its peak gain under motion condition. The antenna system was tested by real modulated Direct Broadcasting Satellite(DBS) signals to check its communication processing function.

• Journal of Aquaculture
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• v.1 no.2
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• pp.135-143
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• 1988

Rotifers became an important live food for fish larvae, especially for marine fishes, and Chlorella has been used as a very useful food for the mass culture of rotifer. However, not many tests for suitable Chorella species for the mass culture of rotifer were done and many of Chlorella sp. have been used without consideration of species for this purpose. There-fore, two species of marine Chlorella and four species of freshwater Chlorella were tested to select suitable species for the mass culture of a rotifer, Brachionus plicatilis. These Chlorella species were cultured in five different culture media; f/2, Erdschreiber, Complesal for marine species and S$\cdot$K, Wai and Complesal for freshwater species. Proximate analyses were done to see the protein, lipid and ash contents of a marine species, C. ellipsoidea and a freshwater species, C. vulgaris. Amino acids content of these species were also tested. C. ellipsoidea and C. vulgaris showed better growth than the other species. For marine Chlorella sp., f/2 media was better than Erdschreiber and Complesal. But for the freshwater species, Complesal showed the best result in growth. By the proximate analyses, C. ellipsoidea has higher lipid contents whereas C. vulgaris has higher protein and ash. In the analysis of amino acid of Chlorella, it was remarkable that freshwater Chlorella, C. vulgaris, has high content of $NH_3$ comparing with marine Chlorella, C, ellipsoidea. According to the above results, C. vulgaris seems have higher possibilities for mass culture of rotifer but further studies are needed.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.2
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• pp.91-98
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• 2017

Background & Object: Basic daily activity screening tool such as the Modified Barthel Index (MBI) has been used commonly in rehabilitation clinic and community based rehabilitation setting. Previous studies have shown the significant relations between the level of daily activities and driving ability on stroke or elderly people. However, there is a lack of studies to investigate the usefulness of MBI on prediction of driving ability for stroke patient. This study was to predict driving abilities of stroke survivor using Korean version Modified Barthel Index (K-MBI). Methods: A sample of 48 patients with stroke in rehabilitation hospital was recruited. All participants were tested level of basic daily activities using K-MBI. The driving ability of participants was tested using virtual reality driving simulator. The predictive validity was calculated of the K-MBI among pass or fail group of driving simulator test using receiver operating characteristics curves. Results: The cut-off score of >86.5 on the K-MBI is proper sensitivity to predict on driving performance ability. Conclusion: This pilot result offers clinical reference to therapists and caregivers for reasoning on driving recommendation period during rehabilitation stage of stroke survivors. Further studies need to identify prediction using real on-road test in a large population group.

• Journal of Sasang Constitutional Medicine
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• v.21 no.1
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• pp.99-126
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• 2009

1. Objective TS-QSCD (The Two-Step Questionnaire for the Sasang Constitution Diagnosis) is one of the self-reporting Sasang-Constitutional diagnosis questionnaires and one constituted by a two-step discriminant function. The process of TS-QSCD is as follows. During the first step, the testers are classified into two groups: the Yangin(陽人) group and Eumin(陰人) group. Following this, the Yangin group is divided into the Soyangin group and Taeyangin group likewise the Eumin group is divided into the Taeumin group and Soeumin group. This questionnaire has the merits of an ordinary questionnaire with four discriminant functions and a decision tree method. The purpose of this study is to evaluate and standardize TS-QSCD 2. Materials and Methods TS-QSCD was administered to 352 random informants who were examined by professionals. Reliability was tested by inter-item consistency using cronbach's ${\alpha}$, and validity was tested by a two step discriminant function. Cross tabulation Analysis was also used to look into the distribution of responses among the groups. 3. Result 1) The reliability of TS-QSCD was relatively valid. The internal consistency of TS-QSCD (AB) was cronbach's ${\alpha}$= 0.815, and TS-QSCD (AC) was cronbach's ${\alpha}$= 0.832. 2) There was a significant difference in points between Eumin group teens and other age groups, between those of Soeumin teens and other age groups. 3) TS-QSCD corresponded with the real Sasang constitution at the rate of 65.0%. When using 61 questions and four discriminant function as with ordinary methods, TS-QSCD corresponded with the real Sasang constitution at the rate of 74.9%. 4. Conclusion 1) TS-QSCD that complements the merits of existing questionnaires is effective in diagnosing Sasang constitutions. 2) Deleting duplicate questions is thought to be one of the reasons for the decreased validity rate. 3) The lower the validity of the first step, the more we should build up at each second steps a way to rescue the groups which were assigned wrongly during the first steps. 4) This standardization of TS-QSCD would be helpful in making a program for diagnosing the Sasang Constitution

• Journal of Life Science
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• v.25 no.7
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• pp.748-756
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• 2015

The report explores the possibility that the single extract of natural substances and the mixture of single extracts of natural substances create a synergy effect to increase the antimicrobial activity. It also compares the previous researches to find out if the natural medicinal herbs’ extract has antimicrobial activity on dandruff causative organism, Malassezia furfur. For the experiment on the mixture of single extracts of natural substances, the results are like following: 1. Staphylococcus aures’s antibacterial activity is resistant to mixture of three natural substances. 2. Escherichia coil’s antibacterial activity is resistant to mixture with Coptidis rhizoma. 3. Candida albicans’ antifungal activity is resistant to mixture with Chinese galls, which means the different results may be expected when tested with each germ. 4. On the other hand, Malassezia furfur has no antifungal activity on the single extract of natural substances and shows weak antifungal activity, whose diameter is 3.20 mm when tested with the mixture of 50% of Coptidis rhizoma and 50% of Phytoncide. The result is totally different from the one on the same eumycetes, C. albicans. That is because M. furfur has more lipophilic chemicaled cell walls than C. albicans does and it also consists of lamella layer, inner plasma membrane and intermediate multiple layers.

• Korean Journal of Food Science and Technology
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• v.26 no.4
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• pp.464-470
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• 1994

The biological activities of Humulus japonicus were extracted by water and methanol. Methanol was better solvent than water in the extraction for antimicrobial activities against six different species of bacteria and two yeasts. The methanol extract was systematically fractionated with various organic solvents which have different polarities. From the result of antimicrobial activities against six species of bacteria and two species of yeasts, methanol extract was superior to water extract. The methanol extract of Humulus japonicus showed antimicrobial activity against the all species of microorganisms tested except Escherichia coli . The butanol fraction of methanol extract showed antimicrobial effect on the all species tested. The minimal inhibition concentration(MIC) of the butanol fraction on the growth of microorganisms was ranged between $0.1{\sim}0.4%$. The water extract of Humulus japonicus did not show inhibition of the activity of trypsin but methanol extract showed inhibitory activity. The chloroform fraction of methanol extract showed comparatively higher trypsin inhibitory activity than other fractions. The concentration of 50% inhibition$(IC_{50})$ by chloroform fraction was 1.0 mg/ml. Enzyme-inhibitor complex formation was above 90% of the while for 20 min. It was revealed that methanol extract of Humulus japonicus inhibited peroxide production of lard and soybean oil as substrate by antioxidative test. The chloroform fraction of methanol extract had the highest activity. When 0.2% of chloroform fraction was added, induction period of soybean oil and lard were extended 15, 9 days, respectively.