• Journal of the Korea Concrete Institute
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• v.27 no.6
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• pp.687-693
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• 2015

The present study proposed a k-value to determine the water-to-binder ratio of concrete using fly ash (FA) or ground granulated blast-furnace slag (GGBS) as a partial replacement of ordinary portland cement (OPC) with regard to an equivalent strength of OPC concrete. From the regression analysis using an extensive database including 7076 concrete mixes, k-values were determined for various water-to-binder ratios when the replacement ratio of OPC by the addition of FA or GGBS were below 50%. For deriving an equation to identify k-value, the relationship of concrete compressive strength and water-to-binder ratio was generalized by an exponential function. In general, k-values decreased with the increases in the addition of FA or GGBS for replacement of OPC and water-to-binder ratio. The rate in decreasing k-value against water-to-binder ratio was marginally affected by the addition of FA or GGBS, although a higher k-value was commonly obtained for GGBS concrete than for FA concrete at the same water-to-binder ratio. Consequently, the determined k-values were simplified as a function of water-to-binder ratio and the addition ratio of FA or GGBS as replacement of OPC.

• Journal of Korean Home Economics Education Association
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• v.32 no.3
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• pp.63-79
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• 2020

This study aimed at analyzing the food safety units of technology and home economics textbooks, as 'safety' emerged as a key concept in the 2015 revised curriculum. From each textbook, the main text, auxiliary elements(including tables, figures, etc.), and related activities were analyzed. According to the results, first, the main texts emphasized the importance of food selection(3.08 pages), food safety hazards(2.93 pages), safe storage and management of food(2.63 pages), and meal preparation with safety and hygiene(0.98 pages). Secondly, when the auxiliary elements were examined, the food safety content was most often presented in the form of tables/illustrations/pictures, followed by supplementary learning materials, activities, captions, end-of-chapter summaries, the chapter introduction and review quiz, and unit introduction. Thirdly, most activities were individual activities rather than small group or collective activities and were focused on investigation, evaluation, craft, application, implementation, inference and judgment, utilization, and proposition. In conclusion, it is recommended for textbooks to evenly distribute the content in the main texts and auxiliary elements, and include more group activities when developing textbooks in the future.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.4
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• pp.496-500
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• 2001

In vitro and in vivo experiments were carried out to evaluate the nutritive value of three tropical browse species as assessed by DM and CP digestibility, and NDF and ADF degradability with incubation times (T) of 6, 12, 24 and 48h. During the in vivo digestibility experiment three male castrated sheep (age 16 - 25 months) with a mean liveweight of $11.5{\pm}0.9kg$ were placed in individual metabolism stalls and were allocated to one of the three browse species in a $3{\times}3$ Latin square design. The browse species were all leguminous and consisted of: Acacia sieberina (A. sieberina), Ficus polita (F. polita), and Ficus sycomorus (F. sycomorus). The mean DM and CP contents of F. polita were higher than for A. sieberina and F. sycomorus (p<0.05). In contrast the NDF and ADF contents of F. sycomorus were higher compared to the other species examined (p<0.05). The in vitro DM and CP digestibility, and NDF and ADF degradability observed at different stages of incubation were higher in F. polita followed by A. sieberina and F. sycomorus. The DM and CP digestibility at 48 h incubation were 72.92, 74.84 and 53.52% and 77.38, 77.68 and 63.64% for A. seiberina, F. polita and F. sycomorus, respectively. This shows that F. polita contains more soluble materials which ruminant can benefit from and hence has more feeding value. The fermentation of F. sycomorus was slower for all the nutrients evaluated due to the presence of more fibre. Similarly, higher in vivo digestibility coefficient of DM, CP, NDF, ADF and hemicellulose were observed for F. polita reflecting its higher values of CP, ether extract (EE) and hemicellulose associated with lower values of NDF and ADF. Higher DMI and daily gain were recorded in sheep during feeding of F. polita compared to the other species evaluated. The digestibility of all the nutrients examined were higher in the in vivo than in the in vitro trial except for CP and DM. Sheep showed no visual signs of toxicity throughout the study periods. These results showed A. seiberina, F. polita and F. sycomorus can sustain sheep on a maintenance diet and could as well be used as a supplementary feed to low producing animals during the tropical dry season. Further research is needed to ascertain the viability of using these browse species on a long-term basis.

• The Journal of Information Systems
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• v.17 no.4
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• pp.233-260
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• 2008

Universities have recognized e-Learning Systems as the critical IT resources which contribute to improving the competitiveness of the universities as well as the quality of the traditional class-based lectures. Instructors deliver the main contents in the class. Other supplementary activities like online discussions, sharing of teaching-learning materials, submission of homeworks, communication among the learners and between the instructors and the learners, and so on can be efficiently facilitated using e-Learning Systems. In other words, e-Learning Systems enable a blended learning combined class-based lectures and e-learning in a variety of ways. Nonetheless, compared to the level of implementation of e-Learning Systems, the usage of both the instructors and the learners is not high. Accordingly, this study examines the determinants to affect on the usage of e-Learning Systems from the learners perspective. To draw the key determinants, we review the IS literatures related to adoption or use of the IS like Media Richness Theory (MRT), Technology Acceptance Model (TAM), Social Influence Model (SIM), and Self-efficacy Model. The variables are drawn out to be expected on the usage of e-Learning like Media Richness, Ease of Use from MRT, TAM and Instructor's Influence, Co-learner's Influence from SIM, and Self-efficacy. To test our model and hypotheses, we have collected data in the class-based lectures using e-Learning System complementary. The results of the test with 192 data are as follows: Firstly, it shows that the Instructor's Influence and the Media Richness are the influential determinants to affect on the Perception of Usefulness of e-Learning Systems. Additionally, the Co-learner's Influence and Ease of Use in order is significant to the Perception of Usefulness. Secondly, as to the degree of use of the e-Learning Systems, the Co-leaner's Influence, the Media Richness, and the Ease of Use are, in that order, the significant determinants. The Perception of Usefulness, also, founded a key factor on increasing the use of e-Learning Systems. On the other hand, the Instructor's Influence is not significant to the use of e-Learning Systems. Finally, it has been found that Self-efficacy is significant to the Perception of Media Richness, Ease of Use, but not significant to the Perception of Usefulness.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.22 no.2
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• pp.137-142
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• 2011

Background and Objectives : The aim of this study is to introduce Korea version of pediatric VHI and to compare pVHI-K scores between children with dysphonia and children without voice problems before pVHI-K is developed as a preliminary study. Additionally, the relationship between pVHI and acoustic measures were investigated. Materials and Methods : pVHI-K scores in normal group were obtained from 15 parents who have children with no present or past history of a voice disorder, hearing loss, or related disability that can affect the their voice or speech. Dysphonia group consisted of 15 parents who have children with bilateral vocal fold nodule's at Department of Otolaryngology, the Seoul National University Hospital (SNUH). pVHI-K and acoustic parameters were measured in two group. Results : The mean pVHI scores (total, functional, physical, emotional) in normal group were 2.33 (T), 0.80 (F) 1.33 (P) and 0.27 (E), respectively whereas those of pVHI in children group with dysphonia were 23.13 (T), 11.07 (F), 5.73 (P) and 6.13 (E), respectively and significant differences were revealed in total pVHI score as well as in all of the sub-pVHI scores. Moreover, significant correlation between pVHI-K parameters (T, F, P) and acoustic measures [Shimmer(%)] were shown in children in dysphonia group. Conclusion : Reported by parents can be useful as a supplementary clinical tool for diagnosing and measuring treatment effectiveness in young children with dysphonia.

• Journal of Engineering Education Research
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• v.6 no.1
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• pp.22-31
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• 2003

The purpose of this study was to develop CD-ROM so that students can understand 8051 Microprocessor unit easily in electronics circuit practice subject of technical high school. The study gives students, who have difficulties in learning, a chance for self-directed and supplementary learning by suggesting interface process with 8051 Practice Kit. To achieve these purposes, literature survey, collecting textbooks and materials, development of CD-ROM were gradually carried out. Each steps were as follows: Firstly, in literature survey, concepts and characteristics of multimedia and application to class were reviewed. Secondly, text contents on 8051 Microprocessor unit were analyzed, main contents were extracted and graphic, sound, animation were made. It was consisted of eight basic learning subjects, and designed to flow systematically. In this study, we presented a kind of teaching-learning material by developing CD-ROM in 8051 microprocessor unit in electronics circuit practice subject as a central matter. This material will be able to help technical high school students in learning

• Journal of Korean society of Dental Hygiene
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• v.6 no.3
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• pp.187-201
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• 2006

The purpose of this study is to examine the satisfaction for college life and oral prophylaxis subject and improve the satisfaction for this subject by satisfying students' desire through the results of correlation, and to inspire a professional sense by helping students enjoy healthy college life. In order to achieve these purposes, 127 senior students of the Dental Hygiene Department, Kwangju Health College took part in this study to examine the satisfaction for a study course, a lab, professors, a college, and subjects. The following results were obtained. 1. The overall satisfaction for the Dental Hygiene Department was 2.83 and the highest dissatisfaction factors included difficult subjects and non-aptitude. The overall satisfaction for professors was 3.33 and students wanted professors' human contact with students and a well-prepared lecture. The overall satisfaction for college life was 2.65, suggesting not very high satisfaction, and the highest dissatisfaction factors included similar life to high school and surrounding environment. 2. The overall satisfaction for theory was 3.83 and for practice was 3.91 in oral prophylaxis. While the highest satisfaction was found in 'the objective and direction of class' and 'class and a supplementary lesson in not giving a lecture', the lowest satisfaction was found in 'experience in reading textbook-related materials or books'. 3. The correlation of the satisfaction of theory and practice of oral prophylaxis was examined. The satisfaction of oral prophylaxis theory was positively correlated with a school course, professors, and college, while the satisfaction of oral prophylaxis practice was positively correlated with a school course, professors, college, satisfaction of oral prophylaxis theory, and present health condition(p<0.05). 4. Factors influencing the satisfaction for the theory of oral prophylaxis included professors, while factors influencing the satisfaction for the practice were statistically significant in professors and health condition(p<0.05). Based on these results, in order for professional dental hygienists to be developed as professionals serving society, it is recommended to enhance the satisfaction for an oral prophylaxis subject and that professors should provide warm-hearted support and become a role model as an educator.

• Journal of Oral Medicine and Pain
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• v.38 no.1
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• pp.87-95
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• 2013

Osteoarthritis (OA) of the temporomandibular joint (TMJ) is a severe form of temporomandibular disorders (TMDs), presenting gradual breakdown of articular cartilage and subchondral bone by the functional load sustained to exceed the physiologic tolerance of the joint. In such a joint loaded, offensive bioactive materials such as matrix degrading proteins, cytokines, and free radicals increase in concentration to shift the tissue response in the joint to degeneration from regeneration or remodeling. Recently, it has been issued that obesity can play an offensive role in pathogenesis of OA in a metabolic way. Adipokines released by adipose cells are present at higher concentration in the arthritic joint and joints of obese individuals. However, because of conflicting data reported, further scientific study should be performed to elucidate the practical role of adipokines in pathogenesis of TMJ OA. As far as the clinical signs and symptoms of TMJ OA are not much different from those of other forms of TMD and any definitive treatment modality to control directly the bone resorptive activity is not available yet, the treatment of TMJ OA should be directed to reduce the physical load and enhance the physiologic tolerance of the joint by means of conservative treatment such as physical therapy, medication, and occlusal splint therapy for sufficient period and, if needed after that, supplementary surgical procedure such as intra-articular injection, arthrocenthesis, and arthroscopic surgery that have turned out to be effective to control OA signs and symtpoms. Enthusiastic reassurance and motivation for patients to control behaviors for themselves to reduce unnecessary functional load in daily life is very important for the joint to reach to more favorable orthopedic stability of the TMJ more quickly, guaranteeing more successful management TMJ OA.

• Journal of the Korea Concrete Institute
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• v.20 no.4
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• pp.439-449
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• 2008

Mineral admixtures are used to improve the quality of concrete and to develop sustainability of concrete structures. Supplementary cementitious materials (SCM), such as silica fume (SF), granulated blast furnace slag (GGBS) and pulverized fly ash (PFA), are gradually recognized as useful mineral admixture for producing high performance concrete. The study on ternary blended concrete utilizing mainly three major mineral admixtures is limited and the study on durability and chloride induced corrosion resistance of ternary blended concrete is very few. This study examines the durability characteristics of the ternary blended concrete composed of different amount of the SCM with ordinary Portland concrete and the study experimentally focuses on corrosion resistance evaluation of ternary blended concrete subjected to chloride attack. In this study, 50% replacement ratio of mineral admixture to OPC was used, while series of combination of $20{\sim}40%$ GGBS, $5{\sim}15%$ SF and $10{\sim}45%$ PFA binder were used for chloride corrosion resistance test. This study concerned the durability properties of the ternary blended concrete including the corrosion resistance, chloride binding, chloride transport and acid neutralization capacity. It was found that the ternary blended concrete utilizing the SCM densified the pore structures to lower the rate of chloride transport. Also, increased chloride binding and buffering to acid were observed for the ternary blended concrete with chlorides in cast.

• Clean Technology
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• v.20 no.4
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• pp.449-456
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• 2014

There has been increasing concerns for the problems of water security in countries, caused by the frequent occurrence of localized drought due to the climate change and uncertainty of water balance. The importance of fresh water is emphasized as considerable amount of usable fresh water is utilized for power generation sector producing electricity. PV power system, the source of renewable energy, consumes water for the every steps of life cycle: manufacturing, installation, and operation. However, it uses relatively less water than the traditional energy sources such as thermal power and nuclear power sources. In this study, to find out the use of water for the entire process of PV power system from extracting raw materials to operating the system, the footprint of water in the whole process is measured to be analyzed. Measuring the result, the PV water footprint of value chain was $0.989m^3/MWh$ and the water footprint appeared higher specially in poly-Si and solar cell process. The following two reasons explain it: poly-Si process is energy-intensive process and it consumes lots of cooling water. In solar cell process, deionized water is used considerably for washing a high-efficiency crystalline silicon. It is identified that PV system is the source using less water than traditional ones, which has a critical value in saving water. In discussing the future energy policy, it is vital to introduce the concept of water footprint as a supplementary value of renewable energy.