• Journal of Periodontal and Implant Science
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• v.33 no.3
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• pp.485-497
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• 2003

Grapefruit seed extract has been reported to have antimicrobial effect. The purpose of this study was to evaluate the antimicrobial and anti-gingivitis effect of chewing gum containing grapefruit seed extract and xylitol. 40 healthy subjects with gingivitis or early periodontitis were divided into two groups. Subjects in the experimental group chewed gum containing grapefruit seed extract and xylitol while subjects in the control group chewed gum containing only xylitol. All subjects received scaling and tooth brushing instruction. 1 week after scaling was set as baseline. Gingival index and plaque index were scored at baseline, 1 week, 2 week, 3 week and 4 week. Bleeding index, probing pocket depth and clinical attachment level were scored at baseline, 2 week and 4 week. The number of total bacteria and Streptococcus mutans in unstimulated saliva of experimental group were counted at 1 week, 2 week, 3 week and 4 week. Gingival indices of experimental group and control group at baseline, 1 week, 2 week, 3 week and 4 week were 0.850${\pm}$0.298, 0.575${\pm}$0.345, 0.533${\pm}$0.332, 0.459${\pm}$0.311, 0.408${\pm}$0.224 and 0.758${\pm}$0.379, 0.592${\pm}$0.276, 0.563${\pm}$0.281, 0.454${\pm}$0.194, 0.413${\pm}$0.199 (mean${\pm}$SD), respectively. Plaque indices of experimental group and control group at baseline, 1 week. 2 week, 3 week and 4 week were 0.497${\pm}$0.500, 0.375${\pm}$0.484, 0.332${\pm}$0.471, 0,286${\pm}$0.452, 0.210${\pm}$0.407 and 0.411${\pm}$0.492, 0.375${\pm}$0.484, 0.354${\pm}$0.479, 0.313${\pm}$0.463, 0.193${\pm}$0.395, respectively. Bleeding indices of experimental group and control group at baseline, 2 week and 4 week were 0.377${\pm}$0.177, 0.298${\pm}$0.152, 0.192${\pm}$0.108 and 0.383${\pm}$0.124, 0.318${\pm}$0.153, 0.225${\pm}$0.126, respectively. Probing pocket depth of experimental group and control group at baseline, 2 week and 4 week were 2.56${\pm}$1.00, 2.40${\pm}$0.65, 2.23${\pm}$0.64 and 2.45${\pm}$0.682.37${\pm}$0.57, 2.19${\pm}$0.57, respectively. Clinical attachment level of experimental group and control group at baseline, 2 week and 4 week were 2.58${\pm}$1.01, 2.43${\pm}$0.67, 2.26${\pm}$0.65 and 2.49${\pm}$0.70, 2.40${\pm}$0.59, 2.22${\pm}$0.62, respectively. The % of reduction of total bacteria in saliva of experimental group at 2 week, 3 week and 4 week were 46 ${\pm}$ 53%, 53 ${\pm}$ 5% and 69 ${\pm}$ 33%. The % of reduction of Streptococcus mutans count in saliva of experimental group at 2 week, 3 week and 4 week were 52${\pm}$69%, 88${\pm}$30% and 89${\pm}$17%. From these findings, it can be concluded that regular use of grapefruit seed extract /xylitol chewing gum may be effective to control and prevent gingivitis and may have caries-preventive effect.

• Journal of Science Education
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• v.33 no.2
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• pp.248-257
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• 2009

The purpose of this study is to investigate the learning achievement of students who has taken the play-based and activity-oriented programs in the class. These new science class programs and instrument to measure student learning achievement were developed for the "Constellation Favorite" lesson of 4th grade students and Those are verified by science education experts, teachers in serve. The subjects of this study consist of 121 students in four classes who were selected on the basis of midterm examination result before teaching treatment. They were divided into two categories with two classes per each category, one class for experimental group and the other class for control group. The experimental groups were given five classes including five play-based class programs. The control groups were given five conventional instruction-type classes. The students were given questionnaires to test their interest ratings. The results show about 17% increase of their learning achievement with (p<0.005) by independent sample T-test method and 40% increase of interest rating in play-based class sample compared to normal class sample. In conclusion, the play-based science class program is found to enhance the students' learning achievement and to interest the students more effectively.

• Journal of Korean Home Economics Education Association
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• v.17 no.3 s.37
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• pp.123-138
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• 2005

The purposes of this study were to develop ICT time management program for middle school students using in the creative extra curricular activities and to test the effect of this program in the knowledge and attitude aspects of time management. The contents of a middle school Home Economics curriculum and nine different textbooks were analyzed Based on these analyses 5 ICT lesson plans on time management were developed. The ICT instructional method was used to develop 5 lesson plans. The second grade middle school students as an experimental group participated in 5 ICT time management classes during middle school creative extra curricular activities. The control group of students who had some condition with the experimental group were taught by traditional instructional methods. After experiment, the changes in attitude and knowledge of time management of both groups were analyzed using Analysis of Covaziance. The significant improvements of attitude and knowledge on time management were found among the experimental group of students compared with control group of students. Thus the following conclusion is made the ICT time management instruction conducted in this study was found loaming more effective than traditional one in attitudes and knowledge of time management

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1C
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• pp.102-110
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• 2004

In this paper, we propose a VLSI structure of real-time image compression and reconstruction processor using 2-D discrete wavelet transform and implement into a hardware which use minimal hardware resource using ASIC library. In the implemented hardware, Data path part consists of the DWT kernel for the wavelet transform and inverse transform, quantizer/dequantizer, the huffman encoder/huffman decoder, the adder/buffer for the inverse wavelet transform, and the interface modules for input/output. Control part consists of the programming register, the controller which decodes the instructions and generates the control signals, and the status register for indicating the internal state into the external of circuit. According to the programming condition, the designed circuit has the various selective output formats which are wavelet coefficient, quantization coefficient or index, and Huffman code in image compression mode, and Huffman decoding result, reconstructed quantization coefficient, and reconstructed wavelet coefficient in image reconstructed mode. The programming register has 16 stages and one instruction can be used for a horizontal(or vertical) filtering in a level. Since each register automatically operated in the right order, 4-level discrete wavelet transform can be executed by a programming. We synthesized the designed circuit with synthesis library of Hynix 0.35um CMOS fabrication using the synthesis tool, Synopsys and extracted the gate-level netlist. From the netlist, timing information was extracted using Vela tool. We executed the timing simulation with the extracted netlist and timing information using NC-Verilog tool. Also PNR and layout process was executed using Apollo tool. The Implemented hardware has about 50,000 gate sizes and stably operates in 80MHz clock frequency.

• Science of Emotion and Sensibility
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• v.17 no.1
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• pp.3-12
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• 2014

Quick and accurate learning of diverse electronic products has become an important daily task. In particular, software occupies core status in the control and operation of the products. This research tested the effects of learning method, schedule, and task difficulty in the learning of software. Using 2 (learning method: experiential vs. verbal) ${\times}$ 2 (learning schedule: spaced vs. massed) ${\times}$ 2 (difficulty: easy vs. difficult) between-subjects design, Experiment 1 tested participants' learning of file control using Windows Movie Maker. There was no effect of learning schedule on task completion time, but participants in experiential learning were faster in the completion of evaluation task compared with those in verbal learning condition. Importantly, as task difficulty increases participants in verbal condition showed markedly lower performance than those in experiential condition, which suggests that experiential learning is more effective with more difficult learning task. That is, in case of learning simple operation of software verbal learning using linguistic manual or instruction could be sufficient; on the other hand in case of learning complex operation learning from experience or tutorial mode would be more effective. Additional studies which manipulated task difficulty (Expt. 2) and inter-trial learning interval (Expt. 3) did not produce meaningful results.

• Journal of Elementary Mathematics Education in Korea
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• v.14 no.3
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• pp.907-935
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• 2010

The purpose of this study was to investigate the effects of using open-ended problems in ability-level activities in mathematics instruction and to draw some informative conclusions in order to improve the practice of teaching and learning mathematics in the elementary school. To fulfill the purpose, the research questions were established as follows: 1. Is there any difference between the academic achievements of the experimental group(doing ability-level activities using open-ended problems) and the control group(doing general ability-level activities)? 2. Which sub-group(grouped by achievement score in pretest) get affected most by ability-level activities using open-ended problem in the experimental group? 3. What kinds of responses do students show in their ability-level activities using open-ended problems? By applying t-test and analysing the response, the conclusions were drawn as follows: First, using open-ended problems in ability-level activities has positive effects on the academic achievement of the experiment group. The mean of posttest scores of the experiment group was statistically meaningfully higher(p<.05). Second, using open-ended problems in ability-level activities affect most to the achievement of lower sub-group in the experiment group. The mean of posttest scores of lower sub-group in the experiment group was statistically meaningfully higher than that of control group(p<.05). Third, students showed various and creative response in their ability-level activities using open-ended problems.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.3
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• pp.284-294
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• 2006

Statement of problem. Proliferation of Candida albicans is primarily within the plaque on the fitting surface of the denture rather than on the inflamed mucosa. Consequently, the treatment of the denture is equally important as treatment of the tissue. Cleansing and disinfection should be efficiently carried-out as the organisms can penetrate into the voids of the acrylic resin and grow in them, from which they can continue to infect and reinfect bearing tissues. Purpose. The purpose of this study was to evaluate the applicability of photocatalytic reaction to eliminate Candida albicans from acrylic resin denture base, and to investigate the anti-fungal effect with various UVA illumination time. Materials and Methods. The specimens were cured by the conventional method following the manufacturer's instruction using thermal polymerized denture base resin (Vertex RS: Dentimex, Netherlands). $TiO_2$ photocatalyst sol(LT), which is able to be coated at normal temperature, was made from the Ti-alkoxide progenitor. The XRD patterns, TEM images and nitrogen absorption ability of the $TiO_2$ photocatalyst sol(LT) were compared with the commercial $TiO_2$ photocatalyst P-25. The experimental specimens were coated with the mixture of the $TiO_2$ photocatalyst sol(LT) and binder material (silane) using dip-coater, and uncoated resin plates were used as the control group. Crystallinity of $TiO_2$ of the specimen was tested by the XRD. Size, shape and chemical compositions were also analyzed using the FE-SEM/ EDS. The angle and methylene blue degradation efsciency were measured for evaluating the photocatalytic activity of the $TiO_2$ film. Finally, the antifungal activity of the specimen was tested. Candida albicans KCTC 7629(1 ml, initial concentration $10^5$ cells/ ml) were applied to the experiment and control group specimens and subsequently two UVA light source with 10W, 353 nm peak emission were illuminated to the specimens from 15cm above. The extracted $2{\mu}l$ of sample was plated on nutrient agar plate ($Bacto^{TM}$ Brain Heart Infusion; BD, USA) with 10 minute intervals for 120 minute, respectively. It was incubated for 24 hours at $37^{\circ}C$ and the colony forming units (CFUs) were then counted. Results. Compared the characteristics of LT photocatalyst with commercial P-25 photocatalyst, LT were shown higher activity than P-25. The LT coated experimental specimen surface had anatase crystal form, less than 20 nm of particle size and wide specific surface area. To evaluate the photocatalytic activity of specimens, methylene blue degradation reaction were used and about 5% of degradation rate were measured after 2 hours. The average contact angle was less than $20^{\circ}$ indicating that the LT photocatalyst had hydrophilicity. In the antifungal activity test for Candida albicans, 0% survival rate were measured within 30 minute after irradiation of UVA light. Conclusion. From the results reported above, it is concluded that the UVA-LT photocatalytic reaction have an antifungal effect on the denture surface Candida albicans, and so that could be applicable to the clinical use as a cleaning method.

• Journal of Acupuncture Research
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• v.27 no.1
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• pp.75-86
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• 2010

Objectives : We developed and proposed a guideline for safety and performance assessment of electric moxibustion apparatus (class II medical device). Methods : We drafted the guideline for safety and performance assessment of electric moxibustion apparatus by referring the existing standards, guidelines and measurement data from commercially available products. Temperature characteristics such as maximum temperature and ramp time, and physical characteristics such as weight, noise and diameter were measured. User friendliness was also evaluated for commercial devices. Results : This guideline only can be applied to the electric moxibustion apparatus where moxa is being heated by electricity for medical proposes. Maximum temperature of higher than $50^{\circ}C$ can be achieved mostly. Ramp rate of temperature seems to be reliable. Control of temperature is needed to be improved. Moxa and its derivative products seem to be regulated for reliable temperature performance for clinical application. Requirements for design and development of electric moxibustion apparatus are suggested : temperature indicator, temperature control and its accuracy, safety measure, surge protection, user friendliness and instruction for use (IFU). Design recommendation of the reduction of noise level and energy loss are suggested for better products. Conclusions : We proposed a guideline for safety and performance assessment of electric moxibustion apparatus to improve the quality of relating products and aid their commercialization by aiming higher industrial competitiveness of the medical device sectors in Korea. Discussion with related institutes such as industry, academy and government is further required. Public hearings also need to be held prior to the establishment of a final guideline and standard.

• Journal of the Korean Chemical Society
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• v.57 no.1
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• pp.115-126
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• 2013

In this study, we developed a explicit and reflective scientific inquiry learning program about nature of scientific inquiry, and compared its instructional influences with those of implicit scientific inquiry learning. We also compared students' perceptions of the program. Eighth graders at a middle school were assigned to the treatment and the control groups. The students of the treatment group participated in the program, while those of the control group participated in general scientific inquiry instruction. The analyses of the results revealed that the program was more effective in improving students' epistemological views on scientific inquiry than general scientific inquiry learning. However, there were no statistically significant differences in both test scores of science achievement and enjoyment of science lessons. The students of the treatment group perceived that group discussion on the nature of scientific inquiry was an advantage of the program. However, they still had difficulties in performing group discussion, understanding the nature of scientific inquiry, and writing and presenting their thoughts. Educational implications of these findings are discussed.

• Journal of Periodontal and Implant Science
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• v.39 no.1
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• pp.87-94
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• 2009

Purpose: The aim of this study was to compare the effectiveness of hydroxyapatite containing toothpaste with positive control toothpastes in reducing dentine hypersensitivity. Materials and methods: This clinical trial was a double-blind, randomized, parallel group comparison of two, namely hydroxyapatite containing toothpaste and strontium chloride containing toothpaste. A total of 55 subjects were included in this study. The subjects were given randomly assigned one of the two toothpastes after received tooth brushing instruction at baseline. Some clinical indices(PI, GI, PD), verbal rating score(VRS) for sensitivity to stimulus, the effect in relieving sensitivity and visual analogue scale(VAS) for sensitivity at baseline, week 2, week 4 and week 8 were assessed. All data were evaluated by intention-to-treat analysis. Results: Overall, PI and GI scores were significantly reduced compare baseline in all groups(p<0.05). In addition, there was significant difference in PI at 4 weeks and in GI at 4, 8 weeks between groups. The proportions of subjects relieved sensitivity were 70.4% in experimental group and 57.1% in control group at 8 weeks respectively. The VRS for sensitivity to three kinds of stimuli and VAS for sensitivity decreased according to time, there was no overall difference between two groups(p>0.05). Conclusion: This study demonstrated that the new hydroxyapatite containing toothpaste was similarly effective in reducing dentine hypersensitivity with pre-existing benchmark toothpaste.