• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.28 no.2
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• pp.435-459
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• 1998

In order to achieve a successful endodontic treatment, root canals must be obturated three-dimensionally without causing any damage to apical tissues. Accurate length determination of the root canal is critical in this case. For this reason, I've used the conventional periapical radiography, Digora/sup (R)/(digital imaging system) and Root ZX/sup (R)/(the frequency dependent type apex locator) to measure the length of the canal and compare it with the true length obtained by cutting the tooth in half and measuring the length between the occlusal surface and the apical foramen. From the information obtained by these measurements, I was able to evaluate the accuracy and clinical usefulness of each systems. whether the thickness of files used in endodontic therapy has any effect on the measuring systems was also evaluated in an effort to simplify the treatment planning phase of endodontic treatment. 29 canals of 29 sound premolars were measured with #15, #20, #25 files by 3 different dentists each using the periapical radiography. Digora/sup (R)/ and Root ZX/sup (R)/. The measurements were then compared with the true length. The results were as follows: 1. In comparing mean discrepancies between measurements obtained by using periapical radiography(mean error: -0.449±0.444 mm), Digora/sup (R)/(mean error: -0.417±0.415 mm) and Root ZX/sup (R)/(mean error: 0.123±0.458 mm) with true length. periapical radiography and Digora/sup (R)/ system had statistically significant differences(p<0.05) in most cases while Root ZX/sup (R)/ showed none(p>0.05). 2. By subtracting values obtained by using periapical radiography, Digora/sup (R)/ and Root ZX/sup (R)/ from the true length and making a distribution table of their absolute values. the following analysis was possible. In the case of periapical film. 140 out of 261<53.6％) were clinically acceptable satisfying the margin of error of less than 0.5 mm. 151 out of 261 (53,6％) were acceptable in the Digora/sup (R)/ system while Root ZX/sup (R)/ had 197 out of 261(75.5％) within the limits of 0.5mm margin of error. 3. In determining whether the thickness of files has any effect on measuring methoths, no statistically significant differences were found(p>0.05). 4. In comparing data obtained from these methods in order to evaluate the difference among measuring methods, there was no statistically significant difference between periapical radiography and Digora/sup (R)/ system(p>0.05), but there was statistically significant difference between Root ZX/sup (R)/ and periapical radiography(p<0.05). Also there was statistically significant difference between Root ZX/sup (R)/ and Digora/sup (R)/ system(p<0.05). In conclusion, Root ZX/sup (R)/ was more accurate when compared with the Digora/sup (R)/ system and periapical radiography and seems to be more effective clinically in determining root canal length. But Root ZX/sup (R)/ has its limits in determining root morphology and number of roots and its accuracy becomes questionable when apical foramen is open due to unknown reasons. Therefore the combined use of Root ZX/sup (R)/ and the periapical radiography are mandatory. Digora/sup (R)/ system seems to be more effective when periapical radiographs are needed in a short period of time because of its short processing time and less exposure.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.587-602
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• 1995

The purpose of this study was to compare the effects of citric acid and tetracycline HCI application to the root surfaces of periodontally diseased teeth on the proliferation and spreading of human periodontal ligament cells. The roots were prepared so that the comparison could be made among root planed, citric acid treated and tetracycline HCI treated surfaces. In the cell proliferation experiment, human periodontal ligament cells at a concentration of $1{\times}10^5$ cells/ml were seeded in each culture well with specimens and incubated for 6 hours. Then, the specimens were transferred to a fresh culture well and incubated for 24, 48, 72 hours respectively. The cell counting was done after trypsinization. In the cell spreading experiment, $1{\times}10^4$ cells/ml were seeded in each culture well and incubated for 30min, 6 hours and 24 hours at 37.5$^{\circ}C$ in a $CO_2$ incubator. Then, all specimens were fixed with phosphate buffered glutaraldehydes, postfixed with phosphate buffered osmium tetraoxide, stained with phosphate buffered tannic acid, dehydrated in ethanol, dried at a critical point, coated with gold and examined under a scanning electron microscope. The results were as follows:In the cell proliferation experiments, the number of attached cells increased more in the tetracycline treated group than in the other groups. In the initial attachment, the appearance of the tetracycline treated the groups was slightly more spread out than in the other groups. After 6 hours of incubation, it was observed in most of the cells that cell morphologic alteration went from ovoid shapes sto spindle shapes. After 24 hours of incubation, the cells of all groups had a fusiform appearance and were connected to each other by numerous cytoplasmic processes. The tetracycline and citric acid treated groups had a similar spreading appearance of periodontal ligament cells, but the tetracycline treated group was more effective in the cell proliferation than the citric acid group.

• Journal of Bio-Environment Control
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• v.24 no.4
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• pp.301-307
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• 2015

High quality transplants are critical for success in crop production. Increasing numbers of growers purchase their transplants from specialized transplant producers instead of growing their own transplants. A drawback of purchasing transplants is the risk of deterioration to transplants during transportation from transplant producers to the growers. This study evaluates the influence of temperature on the quality of grafted tomatoes transplants (Solanum lycopersicum cv. Super Doterang), in order to propose optimum temperature condition for the transportation of grafted tomato transplants. Grafted tomato transplants with visible flower trusses were exposed to different air temperature ($10^{\circ}C$, $25^{\circ}C$, or $40^{\circ}C$) for 2, 4, or 6 hours. After treatment, the NDVI (Normalized Difference Vegetation Index) values of tomato transplants treated at 25 and $40^{\circ}C$ were lower than that at $10^{\circ}C$. The root fresh weight was lowest at $40^{\circ}C$. After transplanting, the transplants that were exposed to the air temperature of $40^{\circ}C$ exhibited chlorosis and blight on lower leaves. The degree of damage on leaves was severer as the high temperature exposure time was longer. The temperature conditions during the transportation also influenced the growth, flowering and fruit set of tomatoes after transplanting. The fruit number and weight of first truss was lowest at $40^{\circ}C$ for 6 hours. Accordingly, it is recommended that the temperature during the transportation should be controlled and kept at the range from 10 to $25^{\circ}C$ even though the period is short (within as six hours) in order to maintain the quality of transplants.

• Journal of Korean Home Economics Education Association
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• v.17 no.4 s.38
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• pp.133-156
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• 2005

This study clarifies the concept of the education content relevance in order to evaluate the content relevance of Technology & Home Economics in a secondary school, and design its standards based on the preceding study. In other words, four standards such as the amount of studying content, the degree of difficulty, the validity of contents and the sequence of contents are established. Also, a survey on the current status of nationwide units targeting students, teachers, and professors was conducted to collect actual data about relevance evaluation. The results are as follows. First, as for the evaluation in terms of the amount of studying content, the majority of respondents answered that it decreased by about $30\%$ when compared to the 6th Technology & Home Economics Curriculum However, middle school teachers pointed out that the number of classes is not enough considering the fact that it's an activity-oriented subject. So, they acknowledged that the amount of study time during a Technology Sl Home Economics class is 'quite a lot.' Second, the evaluation in the degree of difficulty is divided into two responses. Teachers responded that it's reasonable overall, but according to students, it's difficult. Especially, the chapters that students don't understand well including 'The Elements of Draftsmanship,"' 'Understanding of Machinery,' 'Electronics & Electricity Technology,' and 'Energy & Transportation Technology.' In the Home Economics area, 'The Design of Home Life' is the only chapter that students don't understand well. Third, as for the validity of contents, the chapters that were not considered as important considering the objective of Technology Sl Home Economics Curriculum include 'The Elements of Draftsmanship,' 'Computer & Processing,' and 'The Management of Resources and Environment.' Fourth, as for the sequence of contents, the survey was conducted including the name of the course asone of the survey items. The majority of teachers wanted it as it is, but the Professors of education colleges who wanted the 3rd name to connect the course with the elementary school course was a little more $(50.5\%)$ than the ones who don't want any changes $(45.5\%)$. The follow-up study should correct and complement the standards that this study suggested through analytic and critical review according to the character & goal of the subject. Based on such standards, the evaluation of content relevance should be continued to realize the quality control of the curriculum systematically.

• Korean Journal of Health Education and Promotion
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• v.6 no.2
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• pp.23-39
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• 1989

There have been a lot of considerable. discussion and debate surrounding the management model in the health insurance management system and opinions regarding the management operating cost. It is a well known fact that there have always been dissenting opinions and debates surrounding the issue. The management operating cost varies according to the scale of the management organization and component members characteristics of the insurance carrier. Therefore, it is necessary to examine and compare the management operating cost to the simulated management models developed to cover those eligible for the health insurance scheme in this country. Since the management operating cost can vary according to the different models of management, four alternative management models have been established based on the critical evaluation of existing theories concerned, as well as on the basis of the survey results and simulation attempts. The first alternative model is the Unique Insurance Carrier Model(Ⅰ) ; desigened to cover all of the people with no classification of insurance qualifications and finances from the source of contribution of the insured, nationwide. The second is the Management Model of Large-scale District Insurance Carrier(Ⅱ) ; this means the Korean society would be divided into 21 large districts; each having its own insurance carrier that would cover the people in that particular district with no classification of insurance qualifications arid finances as in Model I. The third is the Management Model of Insurance Carrier Divided by Area and Classified with Occupation if Largescale (Ⅲ) ; to serve the self-employed in the 21 districts divided as in Model Ⅱ. It would serve the employees and their dependents by separate insurance carriers in large-scale similar to the area of the district-scale for the self-employed, so that the insurance qualifications and finances would be classified with each of the insurance carriers: The last is the Management Model of the Multi - insurance Carrier (Ⅳ) based on the Si. Gun. Gu area which will cover their own self- employed people in the area with more than 150 additional insurance carriers covering the employees and their dependents. The manpower necessary to provide services to all of the people according to the four models is calculated through simulation trials. It indicates that the Management Model of Large-scale District Insurance Carrier requires the most manpower among the four alternative models. The unit management operating costs per the insured individuals and covered persons are leveled with several intervals based on the insurance recipients. in their characteristics. The interval levels derived from the regression analysis reveal that the larger the scale of the insurance carriers is in the number of those insured and covered. the more the unit management operating cost decreases. significantly. Moreover. the result of the quadratic functional formula also shows the U-shape significantly. The management operating costs derived from the simulated calculation. on the basis of the average salary and related cost per staff- member of the Health Insurance Societies for Occupational Labours and Korean Medical Insurance Corporation for the Official Servants and Private School Teachers in 1987 fiscal year. show that the Model of Multi-insurance Carrier warrants the highest management operating cost. Meanwhile the least expensive management operating cost is the Management Model of Unique Insurance Carrier. Insurance Carrier Divided by Area and Classified with Occupation in Large-scale. and Large-scale District Insurance Carrier. in order. Therefore. it is feasible to select the Unique Insurance Carrier Model among the four alternatives from the viewpoint of the management operating cost and in the sense of the flexibility in promoting the productivity of manpower in the human services field. However. the choice of the management model for health insurance systems and its application should be examined further utilizing the operation research analysis for such areas as the administrative efficiency and factors related to computer cost etc.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.12
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• pp.1896-1904
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• 2020

Objective: Estimating the genetic diversity and structures, both within and among chicken breeds, is critical for the identification and conservation of valuable genetic resources. In chickens, microsatellite (MS) marker polymorphisms have previously been widely used to evaluate these distinctions. Our objective was to analyze the genetic diversity and relationships among 22 chicken breeds in Asia based on allelic frequencies. Methods: We used 469 genomic DNA samples from 22 chicken breeds from eight Asian countries (South Korea, KNG, KNB, KNR, KNW, KNY, KNO; Laos, LYO, LCH, LBB, LOU; Indonesia, INK, INS, ING; Vietnam, VTN, VNH; Mongolia, MGN; Kyrgyzstan, KGPS; Nepal, NPS; Sri Lanka, SBC) and three imported breeds (RIR, Rhode Island Red; WLG, White Leghorn; CON, Cornish). Their genetic diversity and phylogenetic relationships were analyzed using 20 MS markers. Results: In total, 193 alleles were observed across all 20 MS markers, and the number of alleles ranged from 3 (MCW0103) to 20 (LEI0192) with a mean of 9.7 overall. The NPS breed had the highest expected heterozygosity (H_exp, 0.718±0.027) and polymorphism information content (PIC, 0.663±0.030). Additionally, the observed heterozygosity (H_obs) was highest in LCH (0.690±0.039), whereas WLG showed the lowest H_exp (0.372±0.055), H_obs (0.384±0.019), and PIC (0.325±0.049). Nei's DA genetic distance was the closest between VTN and VNH (0.086), and farthest between KNG and MGN (0.503). Principal coordinate analysis showed similar results to the phylogenetic analysis, and three axes explained 56.2% of the variance (axis 1, 19.17%; 2, 18.92%; 3, 18.11%). STRUCTURE analysis revealed that the 22 chicken breeds should be divided into 20 clusters, based on the highest ΔK value (46.92). Conclusion: This study provides a basis for future genetic variation studies and the development of conservation strategies for 22 chicken breeds in Asia.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.241-250
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• 1982

The structure of gonads, gametogenesis and reproductive cycle of the cockle, Fulvia mutice, were studied mainly by histological observation. The materials were monthly sampled in the southern area of Yeosu from October 1980 to September 1981. F. mutica was monoecious. The gonads were situated between the liver tissues and the outer fibronuscular layers compacted by the connective tissue fibers and muscle fibers beneath the outermost layer of simple cuboidal epithelium. The gonad was composed of a number of the ovarian sacs and the testicular tubules which form the tubular structure. Testicular tubules in the mature stage sometimes contained 'testis-ova' The undifferentiated mesenchymal tissues and the eosinophilic cells were abundantly distributed on the germinal epithelium in the early development stage. With the further development of the ovary and testis, these tissues and cells gradually disapprared. The undifferentiated mesenchymal tissues and the eosinophilic cells are related to the growing of the oocytes and spermatocytes . Early multiplicating oogonium was about $10{\mu}m$ in diameter. As the oocytes grow to $27-34\times50-58{\mu}m$ by increasing cytoplasm, the oocytes connected to the basement membrane by their egg-stalks. The ripe eggs were about $60{\mu}m$ in diameter and they were surrounded by gelatinous membrane. Most male germ cells in mature stage were transformed into the spermatozoa and they formed the sperm bundles. After spawning, undischarged ripe eggs and spermatozoa remained in the ovarian sac and the testicular tubule respectively for some time, then they finally degenerated. Especially the early spent ovarian sacs in May did not contract significantly and then they took part in the secondary maturation within two or three months during the summer season. The monthly changes of the fatness well agreed with the reproductive cycle. The reproductive cycle of F. mutica could be classified into six successive stages : multiplicative, growing, mature, spent, degenerative and recovery stage. It seems that the spawning season is closely rotated to the water temperature, and the spawning occurs from May to October at about $20^{\circ}C$ in water temperature. The peak spawning seasons appeared twice a year between June and July and in September. Acknowledgement The authors wish to express their gratitude to Dr. Kim, In Bae, Dr. Chun, Seh Kyu and Dr. Yoo, Sung Kyoo of National Fisheries University of Busan and Mr. Min, Byoung Seo of National fisheries Research and Development Agency for their critical reading of the manu script.

• Knowledge Management Research
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• v.21 no.3
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• pp.249-269
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• 2020

Recently, as the online market has matured, it is facing many problems to prevent the growth. The most common problem is the homogenization of online products, which fails to increase the number of customers any more. Moreover, although the portion of the online market has increased significantly, it now becomes essential to expand offline for further development. In response, many online firms have recently sought to expand their businesses and marketing channels by securing offline spaces that can complement the limitations of online platforms, on top of their existing advantages of online channels. Based on their competitive advantage in terms of analyzing large volumes of customer data utilizing information technologies (e.g., big data and artificial intelligence), they are reinforcing their offline influence as well through this online for offline (O4O) business model. On the other hand, most of the existing research has primarily focused on online to offline (O2O) business model, and there is still a lack of research on O4O business models, which have been actively attempted in various industrial fields in recent years. Since a few of O4O-related studies have been conducted only in an experience marketing setting following a case study method, it is critical to conduct an empirical study on O4O selection attributes and their impact on customer satisfaction and loyalty. Therefore, focusing on China's representative O4O business model, 'Fresh Hema,' this study attempts to identify some key selection attributes specialized for O4O services from the customers' viewpoint and examine the impact of these attributes on customer satisfaction and loyalty. The results of the structural equation modeling (SEM) with 300 O4O (Fresh Hema) experienced customers, reveal that, out of seven O4O selection attributes, four (mobile app quality, mobile payment, product quality, and store facilities) have an impact on customer satisfaction, which also leads to customer loyalty (reuse intention, recommendation intention, and brand attachment). This study would help managers in an O4O area well adapt to rapidly changing customer needs and provide them with some guidelines for enhancing both customer satisfaction and loyalty by allocating more resources to more significant selection attributes, rather than less significant ones.

• Journal of the Korean Society of Costume
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• v.33
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• pp.117-142
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• 1997

This study is on perfume case that is one of a great number of ornaments which was designed by out ancestors. We had developed the tradition and the history of perfume case bag fan-weight etc. These have the same function as the present perfume. case. There were basket-shaped perfume cases which were the smellest one among the personal girdle ornaments in the silla era. The various patterned perfume case were made of gold metal coral platinum or green jadeite etc. In the single-crop trinkets a embroidered perfume bag with the gold and silver thread whose forms perfectly match their functions appeared during the Yi Dynasty. There was also a perfume bag which was one of the daily necessities. A precious "jul perfume" was carried by noble women. A fan-weight perfume bag was attached to the fan to emphasize the intrinsic beauty of utility and function. It is necessary to know the function of prefume case. As perfume case is weared on the clothes it was given more decorative effects as well as the function of medicinal amulet with a sweet smell. Therefore it is very important for us to study perfume case that has various function as an ornament. So The purpose of this study is to investigate the practical and decorative side of perfume case with the general examines of perfume finding how to practice use through our life. The results were as follows; 1. The first use of perfume is perfume through smoke which is for ceremony of religion It removes human body odor by degrees and spreads a sweet odor. Also the materials for making perfume of early age is aromatic plants which will be used flour-made flowers stems. As the materials for making perfume use is increasing today we can invent alcohol perfume today 2. Our country the custom of perfume-used is wide. Among them men's perfume-used was very special phenomenon. For example men were wearing perfume bag in the Silla era. Because perfume represented wealth and noble in those days. They shew off social position personality through perfume-used. 3. One of early religion ceremony article there was the perfume. And perfume case was means for containing perfume. Gradually the perfume case was used widly as increasing needs of perfume in human life. 4. In the middle period of 'Koryo' Dynasty perfume cases had a close relationship with clothes but after Mongolian has been attacked 'Koryo' there were changes in wearing clothes therefore the position of perfume cases were transfered to coat string that was the origin of decoration style that they began. That is to say the perfume case has been influenced the position of perfume case shapes with changing of fashion. 5. The perfume case has been made manifest various function as an ornament. In the practical side First medical-perfume in perfume case has been played an important role in first-aid medicine in critical condition. Second it was amulet for self protection. That is the shape pattern color materials perfume of the perfume case was represented the amuletive nature. Third it was used as substitute article of perfume. Modern women use liquid-perfume as our ancestors used perfume case bag or jul perfume As started above. Also In the decorative side the perfume case has a beautiful formative arts by itself as well as a close relationship with clothes. That well as a close relationship with clothes. That is when the perfume case is worn on the clothes costume is showed aesthetices. That is the materials shapes color pattern of the perfume case we can see the visual beauty also the materials colors embroidered pattern knots tassel that are used the perfume case are increased the decorative beauty of costume. Sixth the symbol in pattern of the pattern case is shown ancetor's wealth and rank health longevity immortality many-born-boy in those days. Today the perfume case is not used with changing of costume by degrees, Accordingly I hope that the result of this study is an influened in devlopment of the perfume case design with matching the modern fashion.

• Journal of radiological science and technology
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• v.35 no.4
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• pp.335-343
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• 2012

Intensity-modulated radiotherapy(IMRT) have the ability to provide better dose conformity and sparing of critical normal tissues than three-dimensional radiotherapy(3DCRT). Especially, with the benefit of health insurance in 2011, its use now increasingly in many modern radiotherapy departments. Also the use of linear accelerator with high-energy photon beams over 10 MV is increasing. As is well known, these linacs have the capacity to produce photonueutrons due to photonuclear reactions in materials with a large atomic number such as the target, flattening filters, collimators, and multi-leaf collimators(MLC). MLC-based IMRT treatments increase the monitor units and the probability of production of photoneutrons from photon-induced nuclear reactions. The purpose of this study is to quantitatively evaluate the dose of photoneutrons produced from 3DCRT and IMRT technique for Rando phantom in cervical cancer. We performed the treatment plans with 3DCRT and IMRT technique using Rando phantom for treatment of cervical cancer. An Rando phantom placed on the couch in the supine position was irradiated using 15 MV photon beams. Optically stimulated luminescence dosimeters(OSLD) were attached to 4 different locations (abdomen, chest, head and neck, eyes) and from center of field size and measured 5 times each of locations. Measured neutron dose from IMRT technique increased by 9.0, 8.6, 8.8, and 14 times than 3DCRT technique for abdomen, chest, head and neck, and eyes, respectively. When using IMRT with 15 MV photonbeams, the photoneutrons contributed a significant portion on out-of-field. It is difficult to prevent high energy photon beams to produce the phtoneutrons due to physical properties, if necessary, It is difficult to prevent high energy photon beams to produce the phtoneutrons due to physical properties, if necessary, it is need to provide the additional safe shielding on a linear accelerator and should therefore reduce the out-of-field dose.