• Journal of the korean academy of Pediatric Dentistry
• /
• v.28 no.3
• /
• pp.403-411
• /
• 2001

The aim of this study was to evaluate the resistance to degradation of four commercial composite resins in an alkaline solution. The brands studied were Unifil(GC, Japan), Palfique(Tokuyama Japan). Definite$Degussa-H\ddot{u}ls$ AG, Germany). Revolution(Kerr, U.S.A.). Preweighed discs of each brand were exposed 0.1N NaOH solution at $60^{\circ}C$. After 14 days they were removed, neutralized with HCl, washed with water and dried. Resistance to degradation was evaluated on the basis of following parameters: (a) mass loss(%) - determined from pre-and post-exposed specimen weights; (b) Si loss(ppm) - obtained from ICP-AE analysis of solution exposed to specimens; and (c) degradation depth$({\mu}m)$ - measured microscopically (SEM) from polished circular sections of exposed specimens. The results were follows: 1. The mass loss of Unifil was 3.21%, it was the highest of materials. But, there was no significant difference among the materials. 2. The degree of degradation layer depth was $107.69\sim47.40{\mu}m$, the sequence of the degree pf degradation layer depth was in descending order by Unifil, Palfique, Revolution, Definite. There was significant difference among the materials except Palfique and Definite. 3. The Si loss of Paltique was 8940.0ppm, it was the highest. There was significant difference among the materials, except Revolution and Definite(p<0.05). 4. The correlation coefficient between mass loss and degradation depth was relatively high(r = 0.06, p<0.05). 5. There was no significant coefficient correlation between Si loss and mass loss, and/or the degree of degradation layer depth and Si loss. 6. When observed with SEM, destruction of bonding is observed between resin matrix and filler. Above results suggested that the hydrolytic degradation is considered as evaluation factor of composite resins.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.30 no.2
• /
• pp.254-262
• /
• 2003

Dental caries has a multifactorial aetiology in which there is an interplay of three principal factors: the host(saliva and teeth), the microflora(dental plaque) and the substrate(diet), and a fourth factor time. There is no single test that takes into consideration all these factors and can accurately predict an individual's susceptibility to dental caries. The risk of dental caries can be evaluated by analysing and integrating several causative factors. The objective of the study was to clarify the relationship between caries activity and the status of caries of primary teeth and the relationship between the quantity of S. mutans in the dental plaque and the status of dental caries. Forty nine children ages 5 were examined with caries indices, Dentocult-SM and quantity of S. mutans. The results were as follows: All the survey results were similar with national means of 5-6 years Korean preschool children. The deft index of subjects was 5.46 and defs index was 9.81. There was 8.6% of negative, 10.9% of mild, 28.1% of moderate and 52.3% of active results at screening strip test. 8.6% was negative, 17.2% was mild, 33.6% was moderate and 40.6% was active in site strip test. The Spearman correlation coefficient was 0.775, and overall kappa index was 0.496 between screening strip test and site strip test. There also was a high correlation between caries incidence, Dentocult-SM test, and quantity of S. mutans. Dentocult-SM test as a caries activity test is a reliable method for measuring the status of dental caries in primary teeth.

• The Korean Journal of Air & Space Law and Policy
• /
• v.29 no.2
• /
• pp.135-161
• /
• 2014

An unmanned aerial vehicle (UAV), commonly known as a drone and also referred to as an unpiloted aerial vehicle and a remotely piloted aircraft (RPA) by the International Civil Aviation Organization (ICAO), is an aircraft without a human pilot aboard. ICAO classify unmanned aircraft into two types under Circular 328 AN/190. Unmanned aircraft, which is the core of the development of the aviation industry. However, there are also elements of the legal dispute. Unmanned aircraft are manufactured in small size, it is possible to shoot a record peripheral routes stored in high-performance cameras and sensors without the consent of the citizens, there is a risk of invasion of privacy. In addition, the occurrence of the people of invasion of privacy is expected to use of civilian unmanned aircraft. If the exposure of private life that people did not want for unmanned aircraft has occurred, may occur liability to the operator of unmanned aircraft, this is a factor to be taken into account for the development of unmanned aircraft industry. In the United States, which is currently led by the unmanned aircraft industry, policy related to unmanned aircraft, invasion of privacy is under development, is preparing an efficient measures making. Unmanned aircraft special law has not been enforced. So there is a need for legal measures based on infringement of privacy by the unmanned aircraft. US was presented Privacy Protection Act of unmanned aircraft (draft). However Korea has many laws have been enacted, to enact a new law, but will be able to harm the legal stability, there is a need for the enactment of laws for public safety of life. Although in force Personal Information Protection Law, unmanned aerospace, when the invasion of privacy occurs, it is difficult to apply the Personal Information Protection Law. So, it was presented a privacy protection bill with infringement of privacy of unmanned aircraft in the reference US legislation and the Personal Information Protection Act.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.8
• /
• pp.1325-1334
• /
• 2013

The purposes of the study were to assess the multicultural competencies and to identify potential barriers toward improving multicultural competencies of food and nutrition majors at the university level. A total of 500 students were surveyed and 457 responses were analyzed for the study. The multicultural competencies, based on a literature review, included food culture knowledge, multicultural attitude, and multicultural skills. Approximately half of the respondents took a food culture class as a college course. The food and nutrition majors showed positive multicultural attitudes; however, food culture knowledge scores for traditional Korean food culture and 11 other food cultures remained low (average score: 63.7 out of 100 points). In addition, familiarity with cultural foods and knowledge of food-related cultures were not necessarily related. As a result of factor analysis, multicultural skills, required for dietitians, were classified into three factors: professional skills, food preparation skills, and communication skills. Overall, students rated their professional skills the highest and communication skills the lowest. Multicultural attitudes and skills increased with school years, and students who took a food culture class showed significantly higher multicultural attitudes and knowledge scores compared to their counterparts. Economical issues, lack of time, and lack of opportunities for learning multicultural competencies in majors and experiencing different cultures were highly rated potential barriers for improving multicultural competencies. Our research indicates that food and nutrition educators should review their curriculums to incorporate content that encourages food and nutrition majors to learn about other food cultures and improve their multicultural competency. These skills will be critical for food and nutrition professionals in the multicultural age.

• Women's Health Nursing
• /
• v.8 no.2
• /
• pp.232-243
• /
• 2002

The purpose of this study was to examine factors influencing the meaning of life for middle-aged women. The subjects for the study were 190 middle-aged women who live in Busan. Data were collected from May 25 to June 20, 1999. The instruments for this study were as follows : the meaning of life scale developed by Jung D. R(1978) ; the self-esteem scale developed by Ro, E. Y, Kwon, J. H.(1997) ; the volunteer activity scale developed by Park G. J.(1999), the marital satisfaction scale developed by Choi G. Y.(1999) ; and the health status scale developed by Kim S. Y. (1991). SPSS PC+ was utilized for data analysis. Data were analysed according to frequency and percentage, mean and standard deviation, t-test, ANOVA, Sheffe' s test and Pearson' s correlation coefficients and stepwise multiple regression. The reliability of the tools was tested by Cronbach's $\alpha$ : and it showed reliability scores of 0.88(for the meaning of life tool), 0.81(for the self-esteem tool), 0.94(for the marital satisfaction tool) and 0.78(for the health status tool). The results were as follows: 1) The scores showed that middle-aged women had a moderate level of meaning of life, with a mean of 30.31 and standard deviation of 6.24 (with values ranging from 12.00 to 48.00). The scores showed that middle-aged women had a moderate levels of self-esteem, with a mean of 28.92 and standard deviation of 4.67 (with values ranging from 10.00 to 40.00). The scores showed that middle-aged women had a very low level of volunteer activity, with a mean of 0.87 and standard deviation of 0.93(with values ranging from 0.00 to 1.00). The scores showed that middle-aged women had a moderate level of satisfaction in their marriages, with a mean of 31.99 and standard deviation of 7.84(with values ranging from 12.00 to 48.00). The scores showed that middle-aged women had a moderate level of health status, with a mean of 6.63 and standard deviation of 1.57(with values ranging from 3.00 to 9.00). 2) There was a statistically significant difference of the meaning of life of middle-aged women according to their religion(F=8.930, p=.000), christian ($31.94{\pm}5.96$) had more meaning th life than buddhists ($28.40{\pm}6.23$). 3) There was a statistically significant correlations between the subject' s self-esteem and the her meaning of life(r=0.477, p=0.000), the subject' s level of volunteer activity and meaning of life(r=.428, p=.000), her level of marital satisfaction and meaning of life(r=.417, p=.000), and her level of health status and meaning of life(r=.261, p=.000) among these middle-aged women. 4) Self- esteem was the highest factor influencing the level of meaning of life in middle-aged women. 40.0% of the total variance of levels of meaning of life by was dependent on self-esteem, volunteer activity, marital satisfaction and health status. In conclusion, the higher the self-esteem and levels of volunteer activity, marital satisfaction, and health status of middle-aged women, the higher the meaning of life for them. Therefore, it is necessary to elevate levels of the self-esteem and volunteer activity, marital satisfaction and health status in order to help middle-aged women have more meaning of life.

• Korean Journal of Adult Nursing
• /
• v.12 no.2
• /
• pp.184-195
• /
• 2000

It has been believed that cancer is an omnious factor threatening the future and life itself. Patients having the disease experience anxiety, fear, feeling of weakness, depression and feelings of uncertainty and hopelessness. Most cancer patients, however, have expectations of possible recovery and a better future, very different from the patients who feel hopeless. Therefore. hope allows people to respond effectively to the fatal disease they have and prevents them from detoriorating physically and spiritually, positively influencing their survival, response to treatment and sense of security. Studies previously performed showed that hope is positively correlated with social and family supports, self-esteem, spiritual well-being, responsive action, health promotion behavior and quality of life. Thus, the study attempted to provide basic information on nursing cancer patients by investigating their levels of hope and determining predictive factors which influence hope. For the study 200 cancer patients in two university hospitals located in Pusan were sampled as subjects. Data were collected for twenty nine days from Feburary 1, 1999 to March 1. Instrumets for the study included 10 items from the self-esteem scale by Rosenberg (1965), 39 hope measurements by Kim and Lee(1965), 16 of the social support scale by Tae(1986) and 16 of the general characteristics scale, all of which totaled 81 items. The data were analyzed using the SPSS program. General characteristics of the investigated based on numbers and percentage. Hope, self-esteem and social support were analyzed using means, minimum, maximum and standard deviation. Relations among the foregoing three factors were analyzed using Pearson' correlation coefficient. Levels of hope in cancer patients were determined using t-test, ANOVA and Scheffe test. Predictive factors influencing hope were investigated using multiple stepwise regression analysis. Results of the study are summarized as follows: 1. An average level of hope was $185.55{\pm}23.39$ points(96 min. and 234 max.) 2. Levels of hope showed a significant difference among them according to sex (t=-3.69, P=.000), age(F=4.714, P=.000), job(F=3.247, P=.008), monthly income (F=6.113, P=.003), treatment charge (F=3.796, P=.011), supportive resources (F=10.554, P=.000), diagnosis(F=2.287, P=.029), perceived health status(F=22.184, P=.000), level of pain(F=3.334, P=.021), religion (F=4.911, P=.001) and religion's effect in life (F=11.706, P=.000), 3. For the subjects, self-esteem and social support were $38.32{\pm}7.21$(13 min, and 50 max.) and $52.97{\pm}8.49$points(28 min, 80 max.). Concerning social support, average levels of family support and medical support were found $35.95{\pm}6.05$(18 min, and 40 max) and $27.02{\pm}4.99$ points(20 min and 40 max). The hope the cancer patients showed significant correlations with self-esteem (r=.588, P=.000), family support(r=.224, p=.001) and medical support(r=.221, P=.002). 4. The five variables related to hope (self-esteem, religion's effect in life, perceived health status, social support and age) accounted for 54.2 percent of the hope level; especially, self-esteem was the highest at 34.6%. As shown in the above results, predictive factors which most influence hope in cancer patients were self-esteem and religion's effect of life. Therefore, nursing interventions to increase self-esteem should be developed. Regarding religion's effects, studies on spiritual aspects should be carried out in a way that contributes to promotion of hope.

• Journal of Bio-Environment Control
• /
• v.26 no.3
• /
• pp.181-187
• /
• 2017

The purpose of this study was to provide basic data for development of environmental design technology for greenhouses constructed in reclaimed lands. The climatic conditions around seven major reclaimed land areas with a plan to install advanced horticultural complexes in Korea were analyzed. The characteristics of natural ventilation and temperature rise through the thermal environment measurement of the greenhouse in Saemangeum were analyzed. The part to be applied to the environmental design of the greenhouses in reclaimed lands were reviewed. Results of comparing the ventilation rate of the greenhouse according to the presence or absence of plants showed the greenhouse with plants had the lower ventilation rate, but the smaller rise of indoor temperature due to the evapotranspiration of plants. In the greenhouse with plants, the number of air changes was in the range of 0.3 to 0.9 volumes/min and the average was 0.7 volumes/min. The rise of indoor temperature relative to outdoor temperature was in the range of 1 to $5^{\circ}C$ and the average $2.5^{\circ}C$. The natural ventilation performance of the experimental greenhouse constructed in the reclaimed land almost satisfied the recommended ventilation rate in summer and the rise of indoor temperature relative to outdoor temperature did not deviate considerably from the cultivation environment of plants. Therefore, it was determined that the greenhouse cultivation in Saemangeum reclaimed land is possible with only natural ventilation systems without cooling facilities. As the reclaimed land is located in the seaside, the wind is stronger than the inland area, and the fog is frequent. This strong wind speed increases the ventilation rate of greenhouses, which is considered to be a factor for reducing the cooling load. In addition, since the fog duration is remarkably longer than that of inland area, the seasonal cooling load is expected to decrease, which is considered to be advantageous in terms of the operation cost of cooling facilities.

• Asia pacific journal of information systems
• /
• v.22 no.4
• /
• pp.7-29
• /
• 2012

Smartphone and its applications (i.e. apps) are increasingly penetrating consumer markets. According to a recent report from Korea Communications Commission, nearly 50% of mobile subscribers in South Korea are smartphone users that accounts for over 25 million people. In particular, the importance of smartphone has risen as a geospatially-aware device that provides various location-based services (LBS) equipped with GPS capability. The popular LBS include map and navigation, traffic and transportation updates, shopping and coupon services, and location-sensitive social network services. Overall, the emerging location-based smartphone apps (LBA) offer significant value by providing greater connectivity, personalization, and information and entertainment in a location-specific context. Conversely, the rapid growth of LBA and their benefits have been accompanied by concerns over the collection and dissemination of individual users' personal information through ongoing tracking of their location, identity, preferences, and social behaviors. The majority of LBA users tend to agree and consent to the LBA provider's terms and privacy policy on use of location data to get the immediate services. This tendency further increases the potential risks of unprotected exposure of personal information and serious invasion and breaches of individual privacy. To address the complex issues surrounding LBA particularly from the user's behavioral perspective, this study applied the privacy calculus model (PCM) to explore the factors that influence the adoption of LBA. According to PCM, consumers are engaged in a dynamic adjustment process in which privacy risks are weighted against benefits of information disclosure. Consistent with the principal notion of PCM, we investigated how individual users make a risk-benefit assessment under which personalized service and locatability act as benefit-side factors and information privacy risks act as a risk-side factor accompanying LBA adoption. In addition, we consider the moderating role of trust on the service providers in the prohibiting effects of privacy risks on user intention to adopt LBA. Further we include perceived ease of use and usefulness as additional constructs to examine whether the technology acceptance model (TAM) can be applied in the context of LBA adoption. The research model with ten (10) hypotheses was tested using data gathered from 98 respondents through a quasi-experimental survey method. During the survey, each participant was asked to navigate the website where the experimental simulation of a LBA allows the participant to purchase time-and-location sensitive discounted tickets for nearby stores. Structural equations modeling using partial least square validated the instrument and the proposed model. The results showed that six (6) out of ten (10) hypotheses were supported. On the subject of the core PCM, H2 (locatability ${\rightarrow}$ intention to use LBA) and H3 (privacy risks ${\rightarrow}$ intention to use LBA) were supported, while H1 (personalization ${\rightarrow}$ intention to use LBA) was not supported. Further, we could not any interaction effects (personalization X privacy risks, H4 & locatability X privacy risks, H5) on the intention to use LBA. In terms of privacy risks and trust, as mentioned above we found the significant negative influence from privacy risks on intention to use (H3), but positive influence from trust, which supported H6 (trust ${\rightarrow}$ intention to use LBA). The moderating effect of trust on the negative relationship between privacy risks and intention to use LBA was tested and confirmed by supporting H7 (privacy risks X trust ${\rightarrow}$ intention to use LBA). The two hypotheses regarding to the TAM, including H8 (perceived ease of use ${\rightarrow}$ perceived usefulness) and H9 (perceived ease of use ${\rightarrow}$ intention to use LBA) were supported; however, H10 (perceived effectiveness ${\rightarrow}$ intention to use LBA) was not supported. Results of this study offer the following key findings and implications. First the application of PCM was found to be a good analysis framework in the context of LBA adoption. Many of the hypotheses in the model were confirmed and the high value of $R^2$ (i.,e., 51%) indicated a good fit of the model. In particular, locatability and privacy risks are found to be the appropriate PCM-based antecedent variables. Second, the existence of moderating effect of trust on service provider suggests that the same marginal change in the level of privacy risks may differentially influence the intention to use LBA. That is, while the privacy risks increasingly become important social issues and will negatively influence the intention to use LBA, it is critical for LBA providers to build consumer trust and confidence to successfully mitigate this negative impact. Lastly, we could not find sufficient evidence that the intention to use LBA is influenced by perceived usefulness, which has been very well supported in most previous TAM research. This may suggest that more future research should examine the validity of applying TAM and further extend or modify it in the context of LBA or other similar smartphone apps.

• Asia pacific journal of information systems
• /
• v.19 no.2
• /
• pp.157-178
• /
• 2009

Corporate credit rating is a very important factor in the market for corporate debt. Information concerning corporate operations is often disseminated to market participants through the changes in credit ratings that are published by professional rating agencies, such as Standard and Poor's (S&P) and Moody's Investor Service. Since these agencies generally require a large fee for the service, and the periodically provided ratings sometimes do not reflect the default risk of the company at the time, it may be advantageous for bond-market participants to be able to classify credit ratings before the agencies actually publish them. As a result, it is very important for companies (especially, financial companies) to develop a proper model of credit rating. From a technical perspective, the credit rating constitutes a typical, multiclass, classification problem because rating agencies generally have ten or more categories of ratings. For example, S&P's ratings range from AAA for the highest-quality bonds to D for the lowest-quality bonds. The professional rating agencies emphasize the importance of analysts' subjective judgments in the determination of credit ratings. However, in practice, a mathematical model that uses the financial variables of companies plays an important role in determining credit ratings, since it is convenient to apply and cost efficient. These financial variables include the ratios that represent a company's leverage status, liquidity status, and profitability status. Several statistical and artificial intelligence (AI) techniques have been applied as tools for predicting credit ratings. Among them, artificial neural networks are most prevalent in the area of finance because of their broad applicability to many business problems and their preeminent ability to adapt. However, artificial neural networks also have many defects, including the difficulty in determining the values of the control parameters and the number of processing elements in the layer as well as the risk of over-fitting. Of late, because of their robustness and high accuracy, support vector machines (SVMs) have become popular as a solution for problems with generating accurate prediction. An SVM's solution may be globally optimal because SVMs seek to minimize structural risk. On the other hand, artificial neural network models may tend to find locally optimal solutions because they seek to minimize empirical risk. In addition, no parameters need to be tuned in SVMs, barring the upper bound for non-separable cases in linear SVMs. Since SVMs were originally devised for binary classification, however they are not intrinsically geared for multiclass classifications as in credit ratings. Thus, researchers have tried to extend the original SVM to multiclass classification. Hitherto, a variety of techniques to extend standard SVMs to multiclass SVMs (MSVMs) has been proposed in the literature Only a few types of MSVM are, however, tested using prior studies that apply MSVMs to credit ratings studies. In this study, we examined six different techniques of MSVMs: (1) One-Against-One, (2) One-Against-AIL (3) DAGSVM, (4) ECOC, (5) Method of Weston and Watkins, and (6) Method of Crammer and Singer. In addition, we examined the prediction accuracy of some modified version of conventional MSVM techniques. To find the most appropriate technique of MSVMs for corporate bond rating, we applied all the techniques of MSVMs to a real-world case of credit rating in Korea. The best application is in corporate bond rating, which is the most frequently studied area of credit rating for specific debt issues or other financial obligations. For our study the research data were collected from National Information and Credit Evaluation, Inc., a major bond-rating company in Korea. The data set is comprised of the bond-ratings for the year 2002 and various financial variables for 1,295 companies from the manufacturing industry in Korea. We compared the results of these techniques with one another, and with those of traditional methods for credit ratings, such as multiple discriminant analysis (MDA), multinomial logistic regression (MLOGIT), and artificial neural networks (ANNs). As a result, we found that DAGSVM with an ordered list was the best approach for the prediction of bond rating. In addition, we found that the modified version of ECOC approach can yield higher prediction accuracy for the cases showing clear patterns.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.10
• /
• pp.505-512
• /
• 2017

The purpose of this study was to determine the quality of life according to the level of subjective perception as well as to analyze the influencing factors and improve the subjective perception to improve the quality of life. The results of the survey for adult patients in hospitals and neighborhood clinics in the region of Busan for nine months from December 2015 were as follows. Regarding the total symptoms, the women had a score of 1.41, and the younger respondents felt they suffered from no symptoms. An analysis of the quality of life by the general characteristics showed that the respondents who were better educated and had no systemic diseases had a higher score of 54.71 on the OHIP-14. The respondents who were better educated and had no systemic diseases had a higher score of 6.48 when a single item was used to determine their happiness index, and the respondents who were better educated and had no systemic diseases had a higher score of 3.82 when five items were used to rate their happiness index. The factor with the greatest influence on their scores on the OHIP-14 was the total symptoms, followed in order by the happiness index and self-rated oral health status. The variable that exerted the largest influence on the happiness index was the OHIP-14, followed by the self-rated health status, high-school or lower education, and the presence or absence of one or more chronic disease. Therefore, an improvement in the subjective awareness level is required to boost the quality of life, and a variety of health education programs should be prepared to raise the awareness level. In addition, there should be a chance to convey accurate information.