• The korean journal of orthodontics
• /
• v.29 no.1 s.72
• /
• pp.83-94
• /
• 1999

The purpose of this study was to evaluate the changes of cancellous and cortical bone and the effect of estrogen in ovariectomized rats. Fifty female rats, 250gm in body weight, were divided into three groups : ovariectomized group(OVE), ovariectomized and estrogen-injected group(OVE-EST), and sham operated and estrogen-injected group(EST). Bilateral ovariectomy was performed at the onset of the experiment. In OVE-EST group and EST group, estrogen was injected $50{\mu}g/kg$ B.W. every other days from 3 weeks after surgery to sacrifice. Each five rats were sacrificed after 5, 6, 7 weeks. One side of mandibular body was radiographed with a soft x-ray apparatus(Hitex Co., Ltd., Japan). Thereafter the obtained microradiographs were used for the morphometric analysis using a Image analyzer. The morphometric analysis was perforrmed for parameters such as total bone area, cortex bone area and medullary bone area. The other side of the mandibular bone was decalcified and embedded in paraffin as using a general method. The specimens were sectioned and stained with Mallory's anilline blue and observed light microscopically. The results were as follows. 1 In all groups, the proportion of cortex to total bone area was not significantly different. 2. In ovariectomized(OVE) group, the proportion of marrow cavity to medullary bone area increased significantly from 5 to 7 weeks(p<0.05). In ovariectomized and estrogen-injected(OVE-EST) group, it decreased significantly at 7 weeks, and in estrogen-injected(EST) group, it decreased significantly from 6 weeks(p<0.05). 3. Microradiogram and histopathologic findings revealed that marrow cavity was enlarged and osteoclasts were observed around irregular bone surface in OVE group. In OVE-EST group, the size of marrow cavity at 7 weeks was similar to that of control group. In EST group, as dense trabecular bone increased from 5 to 7 weeks, marrow cavity decreased.

• Progress in Medical Physics
• /
• v.21 no.2
• /
• pp.137-144
• /
• 2010

The purpose of this study was to evaluate the usefulness of reducing of craniofacial radiation dose using automatic exposure control (AEC) technique in the 64 multi-detector computed tomography (MDCT). We used SOMATOM Definition 64 multi-detector CT, and head of whole body phantom (KUPBU-50, Kyoto Kagaku CO. Ltd). The protocol were helical scan method with 120 kVp, 1 sec of rotation time, 5 mm of slice thickness and increment, 250 mm of FOV, $512{\times}512$ of matrix size, $64{\times}0.625\;mm$ of collimation, and 1 of pitch. The evaluation of dose reducing effect was compared the fixed tube current of 350 with AEC technique. The image quality was measured the noise using standard deviation of CT number. The range of craniofacial bone was to mentum end from calvaria apex, which devided three regions: calvaria~superciliary ridge (1 segment), superciliary ridge~acanthion (2 segment), and acanthion~mentum (3 segment). In the fixed tube current technique, CTDIvol was 57.7 mGy, DLP was $640.2\;mGy{\cdot}cm$ in the all regions. The AEC technique was showed that 1 segment were 30.7 mGy of CTDIvol, 340.7 $mGy{\cdot}cm$ of DLP, 2 segment were 46.5 mGy of CTDIvol, $515.0\;mGy{\cdot}cm$ of DLP, and 3 segment were 30.3 mGy of CTDIvol, $337.0\;mGy{\cdot}cm$ of DLP. The standard deviation of CT number was 2.622 with the fixed tube current technique and 3.023 with the AEC technique in the 1 segment, was 3.118 with the fixed tube current technique and 3.379 with the AEC technique in the 2 segment, was 2.670 with the fixed tube current technique and 3.186 with the AEC technique in the 3 segment. The craniofacial radiation dose using AEC Technique in the 64 MDCT was evaluated the usefulness of reducing for the eye, the parotid and thyroid with high radiation sensitivity particularly.

• Korean Journal of Health Education and Promotion
• /
• v.20 no.2
• /
• pp.35-61
• /
• 2003

Background： The purpose of this study was to develop a structured and individualized smoking prevention program for adolescents by utilizing a multimedia computer-assisted instruction model and to empirically assess its effect. Method： For the purpose of this study, a guide book of smoking prevention program for middle and high school students was developed as the first step. The contents of this book were summarized and developed into an actual multimedia CAI smoking prevention program according to the Gane ＆ Briggs instructional design and Keller's ARCS motivation design models as the second step. At the final step, the short-tenn effects of this program were examined by an experiment. This experiment were made for middle school and high school students and the quasi experimental design was the pretest - intervention - posttest. The measured data was attitude, belief, and knowledge about smoking, interest in the program, and learning motivation. Result： The results of this study were as follows： First, the guide book of a smoking prevention program was developed and the existing literature on adolescent smoking was analyzed to develop the content of the guide book. Then the curriculum was divided into three main domains on tobacco and smoking history, smoking and health, adolescent smoking and each main domain was divided into sub-domains. Second, the contents of the guide book were translated into a multimedia CAI program of smoking prevention througn Powerpoint software according to the instructional design theory. The characteristics of this program were interactive, learner controllable, and structured The program contents consisted of entrance(5.6％), history of tobacco(30％), smoking and health(38.9％), adolescent smoking(22.2％), video(4.7％), and exit(1.6％). Multimedia materials consisted of text(121), sound and music, image(still 84, dynamic 32), and videogram(6). The program took about 40 minutes to complete. Third, the results on analysis of the program effects were as follows： 1) There was significant knowledge increase between the pre-test and post-test with total mean difference 3.44, and the highest increase was in the 1st grade students of high school(p＜0.001). 2) There was significant decrease in general belief on smoking between the pre-test and post-test with total mean difference 0.28. In subgroup analysis, the difference was significantly higher in the 1st grade of high school (p<0.001), low income class (p<0.001), and daily smokers (p<0.01). 3) There was no significant difference in attitudes on his personal smoking between the pre-test and post-test. 4) The interest in the program seemed to lower as students got older. The score of motivation toward this prevention program was the highest in the middle school 3rd grade. Among sub-domains of motivation, the confidence score was the highest. Conclusion： To be most effective, the smoking prevention program for adolescents should utilize the most up-to-date and accurate information on smoking, and then instructional material should be developed so that the learners can approach the program with enjoyment. Through this study, a guide book with the most up-to-date information was developed and the multimedia CAI smoking prevention program was also developed based on the guide book. The program showed positive effect on the students' knowledge and belief in smoking.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.34 no.5
• /
• pp.667-673
• /
• 2005

The purposes of this study were 1) to analyze the preference of leadership style among ${\lceil}$Transformational leadership$\rfloor$ and ${\lceil}$Service leadership$\rfloor$, 2) to examine the differences of the job satisfaction between the high level of service leadership group and low level of the service leadership group and 3) to testify the hypothesis that the service leadership and its 4 elements (belief, attitude, ability, insight) affect the job satisfaction. The questionnaires were developed to measure the service leadership, the preference of leadership style (transfer-mational leadership and service leadership) and Job satisfaction. The surveys were distributed to 120 managers and employees in the family restaurant in Korea, and 104 questionnaires were responded (response rate: $86.7\%$). The SPSS 12.0 package program was used to conduct the descriptive analysis, correlation analysis, t-test and multiple regression analysis. The result of leadership style preference showed the followers preferred the service leadership $(75.0\%)$ to the transformational leadership $(25.0\%)$. Comparing the job satisfaction of high level of service leadership group and that of low level of service leadership group, the job satisfaction of high level of service leadership group was significantly (p<0.001) higher than that of low level of service leadership group (high level of service leadership group: 4.03, low service leadership group: 3.27, measured on a 5-point likert scale). All three factors of job satisfaction (human factor, service system and company image) in high level of leadership group were significantly (p<0.001) higher than those of lower level of service leadership group. The result of multiple regression analysis presented that the service leadership and it's 4 elements (concept, mind, skill, insight) have significant (p=0.000) effects on the job satisfaction. As a conclusion, we examined theoretical framework of service leadership model and testified the applicability in the field of family restaurants. But the service leadership was the new conceptual theory, so there should be the more empirical studies on managers and employees in the service industry.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.28 no.1
• /
• pp.111-126
• /
• 1998

In this study, radiographic evaluation was made using panoramic radiography and cross-sectional tomography of SCANORA/sup (R)/ in male and female adults in their 20's on the relationship between the maxillary sinus floor and the apex of the maxillary molar, to test the accuracy and effectiveness of the cross-sectional tomography, and to use this information in the assessment of preop. and postop. root canal treatment, apical surgery, extraction and implantology. Forty-one adults with an average age of 24.4 years were studied using panoramic radiography and cross-sectional tomography. In panoramic view and cross-sectional view, the position of the apices of maxillary molars were classified as separated, contacted, or protruded type; the general shape of the maxillary sinus floor was evaluated horizontally and vertically from cross-sectional tomography. The accuracy of each radiography was tested using maxilla from 5 fresh cadavers from the Anatomy Lab at Yonsei University Dental College, and panoramic view and cross-sectional tomography were taken in the same condition as with the patients. The results were as follows: 1. Panoramic view and cross-sectional view were taken in the maxilla specimen, and the actual distance between the maxillary sinus floor and the tooth apices were measured in the specimen; the median values of the distance from the tooth apices to the maxillary sinus floor in the panoramic view, cross-sectional view and in the actual maxilla specimen were 2.83 mm, 4.51mm, and 4.l5mm, respectively. In the cross-sectional view, the measured distance was close to the actual distance but in the panoramic view, the measured distance was far from the actual distance. 2. When the results of the panoramic view and cross-sectional view were compared, 40.5％ of the results agreed with each other in the two radiographic methods and buccal roots of the 2nd molar were the closest to the maxillary sinus floor in the cross-sectional tomography. 3. In cross-sectional view, when the vertical relationship of the maxillary sinus floor and maxillary roots was assessed, in 1st molars, type II (the sinus floor that extends down to the buccolingual furcation area) was predominant, while in 2nd molars, type I (the sinus floor located above the level connecting the buccal and lingual apices) was predominant. In the horizontal relationship, in 1st molars, type II (the lowest floor of the maxillary sinus located in between the buccal and lingual roots) was predominant; in 2nd molars, type I (the lowest floor of the maxillary sinus located on the buccal side of the buccal roots) and type II appeared in similar frequency. In conclusion, the SCANORA/sup (R)/ cross-sectional tomography was more effective than the frequently used panoramic view, in that the relationship of the maxillary molars and maxillary sinus floor can be evaluated more accurately and the buccolingual cross-sectional view can also be observed. And maxillary sinus floor that was close to maxillary 2nd molar had tendency to be located on buccal side than that close to 1st molar. Therefore, cross-sectional tomography is an effective and accurate method to evaluate the position of the teeth in relation to the sinus floor preoperative and can be easily used to diagnose localized periapical lesions. Also, the image quality obtained was quite satisfactory.

• Management & Information Systems Review
• /
• v.31 no.4
• /
• pp.167-195
• /
• 2012

This study focuses on the characteristic of socio-psychological gender of a consumer except a biological gender. Socio-psychological gender is the self-image of a consumer which is related to the gender role. The goal of this study is, first, to examine if socio-psychological gender has more effect on the purchase intention than biological gender. Second, by classifying a group with femininity among socio-psychological gender, it is to examine what kinds of shopping value it aims at. Finally, it is to examine the difference between men and women from the purchase intention according to the circumstances. The result of this study is summarized as follows. First, a consumer can have both characteristics of biological gender and socio-psychological gender. There are masculinity, femininity, bisexuality, and undifferentiated type for the classification of socio-psychological gender. This study shows that there is relatively much bisexuality which has masculinity and femininity at the same time. The outcome showed that the purchase intention was higher for the product which corresponds to socio-psychological gender of a consumer than biological gender. Second, it indicated that a group with femininity pursued pleasurable shopping as compared to a group with masculinity. By contrast, it showed that a group with masculinity aimed at practical shopping more greatly. Finally, it showed that while women are less sensitive to the purchase intention at the male-dominated circumstances, men's purchase intention get lower at the female-dominated circumstances.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.43 no.4
• /
• pp.15-26
• /
• 2015

The Daegu Metropolitan Transit Corporation Advisory Committee has chosen 5 styles of bridge-pier designs, including coating, graphic, planting, billboard and safety-facility style, based on the results of landscape simulations from a previous study. This study was conducted to investigate citizen's preferences and emotional images for each style of bridge-pier design, by aiming at the pilot urban landscape improvement section from Daebong Bridge in Suseong Gu to the crossroads near Dongseong Elementary School in Daegu Metropolitan City. The questionnaire was drawn up regarding the urban landscape improvement plans applied to the research area, and the questions were about citizens' perception of bridge-pier structures generated by constructing a light rail transit, important factors to consider when designing bridge piers, preferences for each style of bridge-pier design and emotional impact. 60.4% of the survey participants were found to perceive bridge-pier structures as unattractive, so it was necessary to improve them aesthetically. Regarding visual factors of bridge-pier designs, color was most important at 5.81, followed by form at 5.57. Regarding aesthetic component factors, harmony was most important at 6.07, followed by amenity at 6.00. In the survey participants' preference for each bridge-pier design, the graphic style was preferred most at 4.14, followed by the planting style. In emotional adjectives used for each bridge-pier design, the coating style, the safety-facility style and the non-treatment style showed similar results, and all of these styles were evaluated as artificial, lifeless and desolate. The graphic style and the billboard style showed different tendencies, depending on visual factors and aesthetic component factors applied to the graphic design used for these two bridge-pier styles. Since natural materials were used for the planting style, however, it showed high preference for such emotional images as natural and lively. The emotional adjective 'amiable' was found to affect citizens' preferences for each bridge-pier aesthetic improvement plan most, and it was also analyzed to have an effect on all the styles of bridge-pier designs. To improve the landscape of a light rail transit being constructed inside the urban area, this study quantitatively extracted citizens' preferences and emotional adjective for every style of bridge-pier design applied to the pilot urban landscape improvement section, and it is expected that the results of this study will be used as basic data to improve the landscape of bridge piers.

• Restorative Dentistry and Endodontics
• /
• v.24 no.2
• /
• pp.408-415
• /
• 1999

When a zinc-oxide eugenol type sealer was placed in root canals treated previously with calcium hydroxide, acceleration of its setting and the yellowish discoloration were observed clinically. The purpose of this study was to evaluate the properties of calcium hydroxide-eugenol compound. Some physical properties of calcium hydroxide-eugenol compound were compared with a manufactured zinc-oxide eugenol based root canal sealer, Tubli-seal$^{(R)}$ in terms of water solubility, water sorption, film thickness and microleakage. Solubility and water sorption were determined by the use of the method described in American Dental Association Specification(ADAS) no. 57. Ten samples of each material were prepared into disks 20mm in diameter and 1.5mm in thickness. The samples were immersed in 50ml of distilled water at $37{\pm}1^{\circ}C$ for 7 days. The samples were then removed and placed in a desiccator. The values for solubility and water sorption were calculated using differences between the weights of same sample. Film thickness was determined by the use of the method described in ADAS no. 57 too. A small quantity of mixed cement was placed between two glass plates of which thickness was measured previously. 15Kg loading was applied and total thickness of the glass plates and the cement film was measured. The thickness difference was recorded as the material's film thickness. Microleakage was determined with a dye penetration method. Experimental materials were placed between the dentin surface of bovine tooth and the acrylic rod. These units were immersed in Pelican ink (W-Germany) for three days. Dye-penetrated dentin surfaces of bovine tooth were measured using the NIB Image 1.60 Macintosh program. The results are as follows: 1. Water solubility value of calcium hydroxide-eugenol compound (20.98${\pm}$2.94%) was statistically higher than those of Tubli-seal$^{(R)}$(2.52${\pm}$0.49%)(p<0.05). 2. Water sorption value of calcium hydroxide-eugenol compound (59.72${\pm}$17.75%) was statistically higher than those of Tubli-seal$^{(R)}$(3.15${\pm}$0.76%)(p<0.05). 3. Film thickness value of calcium hydroxide-eugenol compound (0.36${\pm}$0.03mm) was statistically higher than those of Tubli-seal$^{(R)}$(0.12${\pm}$0.1mm)(p<0.05). 4. Dye penetration value after 3 days-immersion of calcium hydroxide-eugenol compound(57.63${\pm}$25.85%) was statistically higher than those of Tubli-seal$^{(R)}$(28.05${\pm}$23.46%)(p<0.05).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2006.05a
• /
• pp.855-858
• /
• 2006

First of all, Developing information technology makes it possible to change a paradigm of all kinds of areas, including an education. Students can choose learning goals and objects themselves and acquire not the accumulation of knowledge but the method of their learning. Moreover, Teachers get to be adviser, and students play a key role in teaming. That is, the subject of leaning is students. Constructivism emphasizes the student-oriented environment of education, which corresponds to the characteristics of hypeimedia. In addition, Internet allows us to make a practical plan for constructivism. Web Based Internet provides us with a proper environment to make constructivism practice md causes an education system to change. Sure Web Based Instruction makes them motivated to learn more, they can gain plenty of information regardless of places or time. Besides, they are able to consult more up-to-date information regarding their learning use hypermedia such as an image, audio, video, and test, and effectively communicate with their instructor through a board, an e-mail, a chatting etc. A school and instructors have been making effort to develop a new model of a teaching method to cope with a new environment change. In this thesis, with 'Design and Implementation of Web Based Instruction Based on Constructivism', providing online learner-oriented and indexed video lesson, learners can get chance of self-oriented learning. In addition, learners doesn't have to cover all contents of a lesson but can choose contents they want to have from a indexed list of a lesson, and they ran search contents they want to have with a 'Keyword Search' on a main page, which can make learners improve learner's achievement.

• Journal of Bio-Environment Control
• /
• v.28 no.4
• /
• pp.461-470
• /
• 2019

This study was carried out to quantify the drought stress in grafted watermelon seedlings non-destructively by using chlorophyll fluorescence (CF) imaging technique rather than the visual judgment. Six-day old watermelon seedlings were grown under uniform irrigation for 3 days, and then given drought stress. Afterward, the sensor for the measurement of water content in plug tray cell unit was used to classify the drought-stress level into nine groups from D1 (53.0%, sufficient moisture state) to D9 (15.7%, extremely dry stress), and the 16 CF parameters were measured. In addition, re-irrigation was performed on the drought stressed seedlings(D5 - D9) to determine the growth and photosynthesis recovery level, which was not confirmed by visual judgment. The kinetic curve patterns of CF in three different drought stressed seedling groups were found to be different for the early detection of drought stress. All the 16 CF parameters decreased continuously with exposure to drought stress and drastically decreased from D5 (32.1%) where the visual judgment was possible. The fluorescence decline ratio (Rfd_Lss) started to decrease from the initial drought stress level (D5 - D6), and the Maximum PSII quantum yield (Fv/Fm) was significantly decreased in the later extreme drought stress range (D7 - D9) by re-irrigation recovery test. Thus, Rfd_Lss and Fv/Fm parameters were finally selected as potent indicators of growth and photosynthesis recovery in the initial and later stages of drought stress. Also, to the differences in the numerical values of the individual chlorophyll fluorescence parameters, the drought stress level was intuitively confirmed through the image. These results indicate that Rfd and Fv/Fm can be considered as potential CF parameters for the detection of low and extremely high drought stress, respectively. Furthermore, Fv/Fm can be considered as the best CF parameters for recovery at re-irrigation.