• Journal of The Korean Association For Science Education
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• v.23 no.1
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• pp.35-46
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• 2003

Problem solving ability, having been thought as one of the most important goals of science education is also a primary task for the current education. Indeed, the students' problem solving ability has shown almost no actual progress, despite our long accumulated science education. Under this circumstances, cooperative learning, a way to grow students' positive inter-dependence and problem solving ability in the basis of their active participation and discussion, was proposed as an effective teaching method. But, results have not consistently shown the advantage of cooperative learning over traditional learning for promoting academic achievement in science. Studies have consistently shown greater effectiveness on affective aspects. But, relatively few have focused on biology in Korea. The purpose of this study was to examine the effects of cooperative learning on the achievement and attitude of high school biology students. The pretest-posttest control group design was applied. The sample consisted of 50 11th-grade female students in experimental group(cooperative learning Student Team Achievement Division model) and 50 students in control group(traditional learning). Students in both groups recieved identical content instruction on the unit 'II. Methabolism'. These groups were treated for 13 hours during 5 weeks. Achievement data were collected using a 24-item multiple-choice test(content validity= .85). Science attitude was measured by an instrument which adapted by Kim In Hee(1994). The instrument(Cronbach $\alpha$=.89) included 40 items in four subscales: attitude toward science, social meaning of science, attitude toward science class, and scientific attitude. An analysis of covariance (ANCOVA) was used as the data analysis procedure. For the achievement data, no significant difference exists between the cooperative and traditional groups (p> .05). But, cooperative learning was effective in low-ability students(p < .05). For the science learning attitude data, cooperative learning was more effective than the traditional one(p< .05). Students in the cooperative group acheived better than those in traditional one especially in the subscale of attitude toward science class. There was no meaningful difference of the two methods in both high and average ability students, while cooperative learning was more effective than the traditional one in low ability students(p<.05).

• Journal of The Korean Association For Science Education
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• v.33 no.7
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• pp.1431-1449
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• 2013

This study is based on the assertion that science museums should consider visitors' views and expectations as they are not satisfied in many cases. In this study, we investigated 31 scientifically gifted students and 177 science high school students about their image of science museums. Using the questionnaire, it was found that only 51% of students visited science museums; however, the average number of visits was 4.2. This means that students tended to re-visit after the first visit of the science museum. Students had a 'good' image of science museums when they incurred hands-on experiences and observed new, interesting, curious and funny exhibits. And students had a 'bad' image of science museums due to the following aspects: lack of new and interesting exhibits, information and guide, diverse contents, and hands-on experience; deficiencies in environment; and inadequacy of the management, operation and composition of exhibits. Therefore, they hoped that science museums will provide more hands-on experiences and experiments, new and interesting exhibits, systematic management and composition of exhibits, information and guides, and a good environment. So science museums need to pay special attention to aspects like management, information guides and environment for the first-time visitors. Based on the above results, we suggested "Directions for a good science museum based on students' views". While asking students what topics they wanted to know and learn in a science museum, each student was given the choice of four topics; eventually, 2.9 answers overlapped for each topic. When classifying students' topics into four main themes for the Gwangju National Science Museum, the order from the most popular theme to the least one was 'science in everyday life', 'ocean/space/future science', 'light and science', and 'culture, art and science'. Among the topics mentioned by students, only 37% are exhibited in Seoul, Gwacheon, Daejeon, or Gwangju science museums. We hope that the results and research methods will be used for evaluation, re-construction, and reinvigorated presentation of science museums.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.1
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• pp.13-22
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• 2009

The composite resin, due to its esthetic quality, is considered the material of choice for restoration of anterior teeth. To get a satisfactory result in the composite resin restorations, it is necessary to choose right shade. At present, most of the commercial composite resins are based on the Vita Lumin shade guides or shade guides that are provided by their company, but color differences among them might be expected even using the same shade in various materials. This study is to measure color differences between various light-cured composite resins and shade guides and to provide the clinicians with information which may aid in improved color match of esthetic restoration. Four kinds of light-cured composite resins (Gradia Direct (GD), Z250 (Z250), Clearfil AP-X (AP-X), Esthet X (E X)) and shade guides with A2 and A3 shade were used. Three specimens of each material and one specimen of each shade guide were made. Each composite resin was filled into the Teflon mold (1.35 mm depth, 8 mm diameter), followed by compression, polymerization and polishing with wet sandpaper. Shade guides were grinded with polishing stones and rubber points to a thickness of approximately 1.35 mm. Color characteristics were performed with a spectrophotometer(color i5, GretagMacbeth, USA). A computer-controlled spectrophotometer was used to determine CIELAB coordinates ($L^*$, $a^*$, $b^*$) of each specimen and shade guide. The CIELAB measurements made it possible to evaluate the amount of the color difference values (${\Delta}E^*ab$) between composite resins and shade guides. CIE standard D65 was used as the light source. The results were as follows : 1. Among the $L^*$, $a^*$, $b^*$ values of most of 4 kinds of composite resin specimens which are produced by same shade, there were significant differences(p<0.05). 2. Among all 4 kinds of composite resin specimens which are produced by same shade, there were color differences that is perceptible to human eye(${\Delta}E^*>3.3$). 3. Between most of composite resin specimens investigated and their corresponding shade guides, there were color differences that is perceptible to human eye(${\Delta}E^*>3.3$). 4. In the clinical environment, it is recommended that custom shade guides be made from resin material itself for better color matching. Shade guides supplied by manufacturers or Vita Lumin shade guide may not provide clinicians a accurate standard in matching color of composite resins, and there are perceptible color differences in most of products. Therefore, it is recommended that custom shade guides be made from resin material itself and used for better color matching.

• Sleep Medicine and Psychophysiology
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• v.18 no.2
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• pp.87-94
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• 2011

Objective: OSAS (obstructive sleep apnea syndrome) is a common disorder and its consequences are often serious. It is important to detect the disorder early in the course for proper treatment. This study is to grasp the snoring clinic visitors' knowledge level of OSAS. Method: One hundred and seventy-nine visitors at the of snoring clinic of Seoul National University Hospital were surveyed by questionnaire about reasons of visit and knowledge of treatment methods of snoring and OSAS, diagnostic method, OSAS-related symptoms, and complications. Results: Most of the respondents (89.4%) "have already heard about OSAS" and the major sources of information was the mass media (58.1%) such as television and radio. More than half (60.3%) were aware that snoring is closely related to OSAS. More than half (59.8%) recognized that a nocturnal polysomnograpy was necessary for proper diagnosis. Two thirds (67%) of the respondents noted surgery as a treatment for snoring. More than half (55.9%) answered that they would follow the doctor's advice on the treatment choice. Only 12.3% of respondents "have heard about nCPAP". No one chose nCPAP (nasal continuous positive airway pressure) as a treatment for either snoring or OSAS. About one third (34.6%) of the respondents were aware that OSAS is related to hypertension. Only 12.8% noted that OSAS is related to diabetes mellitus. Conclusion: Visitors at the snoring clinic were found to have substantially limited knowledge of health risks and proper treatments of OSAS. We suggest that it is crucially important to educate patients and offer easy-to-understand information on snoring and OSAS. We predict that provision of educaiton and information to patients and general public will faciliate the diagnosis and treatment of snoring and OSAS and reduce the related disorders such as hypertension, stroke, and diabetes mellitus.

• Tuberculosis and Respiratory Diseases
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• v.46 no.1
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• pp.65-74
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• 1999

Background : Open lung biopsy(OLB) has conventionally been regarded as the gold standard for the diagnosis in interstitial lung disease. With recent advances in diagnostic technique such as high resolution computed tomography(HRCT), and transbronchial lung biopsy(TBLB) which provide relatively accurate diagnosis of ILD, it is necessary to reevaluate the role of these methods in the diagnosis of ILD. Methods: We carried out a retrospective analysis of nineteen patients who underwent OLB at Dankook University Hospital for the diagnosis of acute and chronic ILD, between May 1995 and June 1998. By reviewing the medical records, the demographic findings, underlying conditions, HRCT and TBLB findings, OLB diagnosis, therapy after OLB, and complication of OLB were evaluated. Results: Thirteen patients(68.4%) had chronic ILD(symptom duration over 2 weeks prior to OLB), and six patients(31.6%) had acute ILD(symptom duration less than 2 weeks). Specific diagnosis were reached in 92%(12/13) of chronic ILD(5 bronchiolitis obliterans organizing pneumonia(BOOP), 2 constrictive bronchiolitis, 3 usual interstitial pneumonia, 1 hypersensitivity pneumonitis, 1 eosinophilic pneumonia), and in all patients of acute ILD(5 acute interstitial pneumonia, 1 pneumocystis carinii pneumonia). HRCT were performed in all patients and a correct first choice diagnosis rate of HRCT was 42%(5/12) in chronic ILD. In chronic ILD patients, 62%(8/13) received specific therapy(steroid therapy in 7 patients and moving in one patient), after OLB, but in acute ILD, all patients received specific therapy(steroid therapy in 5 patients and steroid and antibiotic therapy in one patient) after OLB. The in-hospital mortality after OLB was 5.3%(1/19). Conclusion: OLB is an excellent diagnostic technique with relatively low complications in patients with ILD. Therefore OLB should be considered in patients with ILD when the specific diagnosis is important for the treatment, especially in patients with acute ILD.

• Tuberculosis and Respiratory Diseases
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• v.43 no.5
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• pp.755-762
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• 1996

Background : Continuous positive airway pressure(CPAP) is doubtlessly using as a medical treatment of choice for patients with obstructive sleep apnea (OSA) syndrome. CPAP is effective in OSA patients as a physical "pneumatic pressure splint" mechanism. We have done this study for two purposes, first to seek for the factors to determine the optimal CPAP titer, second to predict the minimal CPAP titer using the determined factors. Methods: We studied a 72 OSA patients who were treated with CPAP. All of them were studied by using a two nights polysomnographic rests in hospital. We compared the patients requiring CPAP over $10cmH_2O$ with those who required CPAP under 5cm $H_2O$ to determine the factors affecting the minimal CPAP titer. Results : The high CPAP group is characterized by a significantly higher body mass index(BMI), apnea index(AI) and apnea and hyponea index(AHI) and significantly lower lowest $SaO_2$. Regression analysis using the optimal four variables resulted in the following prediction equation for CPAP titer. CPAPtiter=8.382 + 0.064 ${\times}$ BMI + 0.077 ${\times}$ AI - 0.004 ${\times}$ AHI - 0.077 ${\times}$ lowest $SaO_2$ When this regression equation was applied to the 72 patients, the mean CPAP titer as predicted by the above equation was $7.80{\pm}2.96$ mmHg. Compared this value with actually determined CPAPtiter, $7.93{\pm}4.00$mmHg, there was no significant difference between the two values. Conclusion: Obesity, apnea severity and lowest Sa02 were strongly correlated with CPAP titer. Linear regression equation for CPAP titer using these indices predicted very closely the actually measured values in the sleep laboratory.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.12C
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• pp.1288-1298
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• 2002

To implement elliptic curve cryptosystem in GF(2$\^$m/) at high speed, a fast divider is required. Although bit-parallel architecture is well suited for high speed division operations, elliptic curve cryptosystem requires large m(at least 163) to support a sufficient security. In other words, since the bit-parallel architecture has an area complexity of 0(m$\^$m/), it is not suited for this application. In this paper, we propose a new serial-in serial-out systolic array for computing division operations in GF(2$\^$m/) using the standard basis representation. Based on a modified version of tile binary extended greatest common divisor algorithm, we obtain a new data dependence graph and design an efficient bit-serial systolic divider. The proposed divider has 0(m) time complexity and 0(m) area complexity. If input data come in continuously, the proposed divider can produce division results at a rate of one per m clock cycles, after an initial delay of 5m-2 cycles. Analysis shows that the proposed divider provides a significant reduction in both chip area and computational delay time compared to previously proposed systolic dividers with the same I/O format. Since the proposed divider can perform division operations at high speed with the reduced chip area, it is well suited for division circuit of elliptic curve cryptosystem. Furthermore, since the proposed architecture does not restrict the choice of irreducible polynomial, and has a unidirectional data flow and regularity, it provides a high flexibility and scalability with respect to the field size m.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.4
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• pp.329-338
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• 2010

Objective: This study was carried out to know whether cryopreservation of sibling 2PN zygotes could increase the cumulative delivery rates in the patients who had less than 10 fertilized zygotes. Methods: A retrospective analysis was performed in 138 in vitro fertilization-embryo transfer (IVF-ET) cycles with less than 10 fertilized zygotes during January 2003 to December 2007 in Cheil General Hospital. These cycles were divided into two groups. In Group I (n=86), all fertilized embryos were cultured to transfer on day 3 without cryopreserved embryos at the 2PN stage. In Group II (n=52), among fertilized zygotes, some sibling zygotes were frozen at the 2PN stage, the remainder were cultured to transfer. Clinical outcomes in fresh ET cycles and cumulative ongoing pregnancy rates after subsequent frozen-thawed (FT)-ET cycles were compared. Results: There were no significant differences in female mean age, number of retrieved oocytes and total fertilized embryos between two groups, Number of cultured embryos was significantly lower in Group II ($5.2{\pm}0.5$) than in Group I ($8.4{\pm}0.7$) (p<0.01). Also, number of transferred embryos was significantly lower in Group II ($3.3{\pm}0.6$) compared with Group I ($3.6{\pm}0.6$) (p<0.01). ${\beta}$-hCG positive rates and delivery rates (51.2 vs. 46.2 % and 41.9 vs. 34.6 %, respectively) after fresh ET were slightly higher in Group I than in Group II. However, the differences were not statistically significant. Also, the cumulative delivery rates after subsequent FT-ET cycles were not significantly different between Group I (48.8%) and Group II (50.0%). Conclusion: This study showed that cryopreservation of sibling 2PN zygotes from patients who had less than 10 zygotes in the fresh ET cycles did not increase cumulative delivery outcomes. But, it could provide an alternative choice for patients due to offering more chance for embryo transfers if pregnancy was failed in fresh IVF-ET cycles.

• Food Science and Preservation
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• v.19 no.5
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• pp.783-791
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• 2012

The purpose of the study was to provide baseline information that could encourage consumers and establish the direction of development for sprouts and leafy vegetables. A survey on the consumption and preference for sprouts and leafy vegetables of 823 people over 20 years of age in Seoul and Gyeonggi province was conducted. The preference for sprouts was higher in men ($3.75{\pm}0.96$) than in women ($3.64{\pm}0.84$), whereas the preference for leafy vegetables was higher in women ($4.06{\pm}0.74$) than in men ($3.88{\pm}0.90$). Based on age, the respondents in their 40s or above had high preferences for sprouts and leaf vegetables due to the importance that they accorded to health and nutrition (p<0.01). The sprouts and leafy vegetables were purchased mainly for their high nutritional value. The purchase frequency of once a month or more for leafy vegetables (82.7%) was higher than that for sprouts (57.1%). The consumers purchased sprouts and leafy vegetables mainly from a large discount store. The respondents in their 20s showed the highest percentage of purchasing from a local store whereas the older ones showed a high preference for traditional markets. The reason for the choice of the place of purchase was convenience. The freshness and price were important factors in the consumption of sprouts and leafy vegetables. In the case of leafy vegetables, the consumers preferred to buy them using the conventional weight measurement system rather than in small packages. On the other hand, mixed small packages were preferred for sprouts. The purchase frequency was correlated with the preferences, need for improvement and purchase intent for sprouts and leafy vegetables. The aspects that require improvement for producing high-quality sprouts and leafy vegetables were the nutritional and functional properties. To increase the consumption of sprouts and leafy vegetables, there is need for variations and improvement of the quality and safety of the products.

• Journal of dental hygiene science
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• v.8 no.4
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• pp.267-274
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• 2008

The purpose of this study was to examine the use of dentifrice among children in a bid to provide information on dentifrice including its function to children's parents, the major consumers of dentifrice for child. And it's additionally meant to offer useful information on the production of toothpaste for kid. The subjects in this study were parents with children, who dwelled in Seoul and Gyeonggi province. After a self-administered survey was conducted for about three months from May to July 2007 to gather data on their use of dentifrice for child, a comparative analysis was implemented. The findings of the study were as follows: 1. Concerning the state of the use of their children's dentifrice, the largest number of the children(58.1%) started to use toothpaste at the age of one or down, and the most common first toothpaste they used was dentifrice for preschooler(86.8%). As for whether to use fluoride-containing toothpaste, the largest group of the parents(58.1%) gave an affirmative answer. Regarding the form of the toothpaste in use, the majority of their children used toothpaste of cream type(86.2%). The greatest group of the children used the amount of toothpaste that was as large as the three-tenths or four-tenths of the bristles(35.9%). 2. As for the state of the use of dentifrice for kid, the greatest group used that kind of toothpaste(81.4%). In the event of those who didn't use it, the last time when their children used toothpaste for kid was when they were at the western age of 3(33.9%) and 4(33.9%). Concerning the reason why they replaced toothpaste for kid with one for adult, the largest group of the parents did that on their own judgment(58.1%). As to the right time for replacing toothpaste for kid by one for adult, the greatest group considered it advisable for children to start using toothpaste for adult at the western age of 4 or 5(43.2%). 3. In relation to the state of the purchase of toothpaste for their children, the largest group was under the moderate influence of the children when they bought it(45.2%). The greatest group attached importance to the ingredients of toothpaste(41.6%), and the most preferred ingredient was fluoride(56.3%). 53.0 percent took consideration on the content of ingredients or the instructions. 4. In regard to priorities for the choice of toothpaste for their children, they gave top priority to brand(16.7%), followed by quality(14.6%) and ingredients(13.5%). The age of the parents made a statistically significant difference to the children's age when they started using toothpaste, and how they started to do that and whether they used fluoride-containing toothpaste were statistically significantly different according to that as well(p < 0.01). In regard to the impact of the occupation of the parents, the use of fluoride-containing toothpaste was more common among the stay-at-home mothers(p < 0.01).