• Journal of agricultural medicine and community health
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• v.28 no.2
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• pp.171-182
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• 2003

Objectives: This study was conducted to analyze the dental care utilization patterns and related factors of the rural residents. Methods: The data collected by interview and self-administered questionnaire survey of 524 peoples of Seongju county in Gyeongsanbuk-do. The summarized results are as follows. Results: The rate of persons who experienced the oral disease was 52.5% during 1 year and it was at most in the age group of 40-49. The rate of persons who had experienced the oral disease were investigated according to general characteristics, perception of oral health, being of regular treatment facility. Therefore the rate of persons who had experienced the oral disease was significantly higher the younger peoples, worse oral health status and being of the regular treatment source than the other groups. During 1 year period, 64.0% of the cases had treated the perceived oral disease, 36.0% did no action at all during last year. Among respondents, 49.4% had treated their oral disease at dental clinics, 8.0% had treated at community health center or subcenter and remains did not treated at all. The results of logistic regression analysis suggested that statistically significant factors in dental health care utilization were educational level, degree of pain, oral health status and regular treatment facility. Therefore the dental health care utilization rate was higher at groups with the high educational level, serious pain, better oral health status and being of the regular treatment source than other groups. 45.5% of the rural residents did not treat their oral disease immediately due to the no identified need, limitation of time(19.2%), economic limitation(19.2%), and geographical limitation(9.0%). Conclusions: In consideration of above findings, we may conclude that oral health community program to prevent oral diseases should be intensified, oral health education to raise oral health knowledge should be performed periodically.

• Journal of Technologic Dentistry
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• v.28 no.1
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• pp.121-142
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• 2006

Collecting materials for study on teaching efficiency and satisfaction of clinical training, it changes. Dental technology's educational procedure to many ways of a prospect. In a circumstance that needed higher level of education, this study is aimed on realizing an importance of clinical training through the various materials that previously carried out and offering basic knowledge to take better clinical training for the students. Study results below 1. This Investigation conducted on 123 of sophomores(70.3%) and 52 of juniors(29.7%) who have been taken clinical training, and men's proportion(51.45%)is a bit higher than girls(48.6%). The 64% of respondents taken largest proportion were 20 to 24 years old. As 67.9% of respondents attended daytime school and 30.3% of them attended nighttime one, their school time shows a little difference. In a question about relation ship, one answered "Harmonious" took largest proportion by 72.6% during training, and about the degree of satisfaction of campus life who answered "normal" were the most with 59.4%. 2. About the reason choosing dental technology as a major, 41.1% taken the most answered "due to the specialized job", "Getting job easily" was second with 26.9%, and third was "recommended from around" with 18.3%. 50.3% of the respondents answered "normal" about the Satisfaction of their major, student marked in grade "B" most with 51.4% 3. In a investigation result about clinical training statues and preference, most(72.6%) choose place less than 10 for clinical training, and 60.6% of them resided own home. About their commuting time from home to training place, 44% was under 30min, 40% took time 30-60min. It shows students prefer shotter distance in terms of choosing training place. 4. Each part manager took large proportion as a clinical trainer with 33.7%, Training curriculum reform and developing method were most answer as a improvement measure after completing training with 30%. 5. The average of total score about clinical training was 3.15 of 5. In the detailed question, 'satisfaction of clinical training' got 3.38 as a highest score, the lowest score was 2.86 that is about satisfaction of clinical training period. The average score about efficiency of study was 2.86 and in detailed question, 'a Role model' got 3.26 as a highest score and participation of student got 3.05 as a lowest score. 6. The result of T-test to see the difference of the satisfaction according to the general character and clinic training condition between teaching efficiency is that the degree of satisfaction of clinical training showed statistical significance only in the degree of satisfaction of campus life(p<0.05), and teaching efficiency has a statistical significance with their age, grade, and satisfaction of campus life (p<0.05). 7. The relation between of teaching efficiency of clinical training and satisfaction of clinical training of dental technologic student has a statistical meaning in significance leveler 0.01. Now, therefore we suggest following based on these result. 1. To elevate satisfaction of clinical training, it agentry needs development of consistent clinical training curriculum. 2. To grasp the satisfaction and requirement, in needs to measure anxiousness and satisfactory degree after completing training 3. To train efficiently and evaluate efficiency over the teaching activities, it needs to develop measuring tools for teaching efficiency in terms of teacher's important rules in a clinical training. 4. Strengthen the relations with the study developing and managing curriculum gathering theoretical knowledge and practice. And make an effort to apply to their students. 5. Let the trainee take a class setting a belief, sense of value, function and obtain behavior by making the students comfort over clinical training as increasing teaching efficiency.

• Journal of the Korean Institute of Gas
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• v.23 no.6
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• pp.90-96
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• 2019

Natural gas has been regarded as one of major alternative fuels, because of the increment of mining shale gas and supplying PNG(Pipeline Natural Gas) from Russia. Thus, it needs to broaden the usage of natural gas as the increasing its supplement. In this situation, application of natural gas on the transport area is a good suggestion to reduce exhaust emissions such as CO₂(carbon dioxides) and soot from vehicles. For this reason, natural gas can be applied to SI(spark ignition) engines due to its anti-knocking and low auto-ignitibility characteristics. Recently, since turbocharged SI engine has been widely used, it needs to apply natural gas on the turbocharged SI engine. However, there is a major challenge for using natural gas on turbocharged SI engine, because it is hard to make natural gas direct injection in the cylinder, while gasoline is possible. As a result, there is a loss of fresh air when natural gas is injected by MPI (multi-point injection) method under the same intake pressure with gasoline-fueled condition. It brings the power reduction. Therefore, in this research, intake pressure was increased by controling the turbocharger system under natural gas-fueled condition to improve power output. The goal of improved power is the same level with that of gasoline-fueled condition under the maximum torque condition of each engine speed. As a result, the maximum power levels, which are the same with those of gasoline-fueled conditions, with improved brake thermal efficiency could be achieved for each engine speed (from 2,000 to 6,000 rpm) by increasing intake pressure 5-27 % compared to those of gasoline-fueled conditions.

• The Korean Journal of Air & Space Law and Policy
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• v.29 no.2
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• pp.135-161
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• 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 Korean Society of Forest Science
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• v.96 no.3
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• pp.269-282
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• 2007

The purpose of this study is to investigate the causes of the dramatic process in forest policies from July of 1972 to June of 1973. In 1972, the core forest problem calling for an immediate solution was the severe forest degradation such as a low growing stock ($11m^3/ha$) and lots of non-tree forest land corresponding to 12% of total forest land. There could have been various approaches to solve the problem at that time. By the end of 1972, the Korean government was afoot to choose the management-oriented approach to carry out reforestation as a part of forest management. In order to implement this approach, the Korean government established the Forest Development Law enforcing establishment of the Forest Management Corporation as a public organization to carry out forest management in the special development land. However, the Korean government changed the management-oriented approach into the administration-oriented approach to carry out reforestation as a part of forest greening in order to rehabilitate severe degraded forests as soon as possible in early 1973. The Forestry Administration (refer to Forest Service) was transferred from the Department of Agriculture and Forestry to the Department of Interior for the efficient rehabilitation in advance, before the 1st 10-year National Greening Project. After the organization's transfer, the government established the 1 st 10-year National Greening Project aiming to reforest one million ha from 1973 to 1982 to use activities like the national greening campaign and the administrative organization mobilization including police force. Reforestation policy as a part of forest management lost effect due to the greening-oriented approach choice. Moreover, the Government struggled to provide 20 billion won for the establishment of the Forest Management Corporation. After all, on March 5th of 1973, the management-oriented approach dropped a curtain deleting the clauses defining the establishment of the Forest Management Corporation. Park, Chung-hee who was the then president of Korea might have felt the 'time restriction' to lose no time to habilitate degraded forests. Due to his awareness, the approach regarding reforestation was changed into administration-oriented activities. The president's awareness was considered as an invisible cause at that time.

• Journal of Korean Society of Forest Science
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• v.104 no.3
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• pp.434-442
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• 2015

The process of cultivation and production of oak mushroom (Lentinula edodes (Berk.) Pegler) on sawdust surface beds were investigated. Sawdust surface bed cultivation is the method by which oak mushrooms are cultured and produced on sterilized sawdust surface bed without using bags. The bed was made by inoculating with 3 to 1 ratio of bed sawdust to oak mushroom mycelial inoculum. The sawdust bed medium with 65% water content was pasteurized at $65^{\circ}C$, inoculated with sawdust spawn and spread on the surface on vinyl film in cultivation shed. During 78 days of cultivation period, water content in the medium varied from 61 to 72%, its pH decreased from 5.6 to 3.9~4.6 and ergosterol concentration increased to $0.33{\sim}0.59{\mu}g/g$. $CO_2$ concentration in the medium rapidly increased to 8.06% in two weeks. In seven weeks the medium surface started browning and $CO_2$ concentration increased to about 5.63%. Until 11th week the $CO_2$ concentration was maintained at 6~7%. After removing the plastic cover on the bed for ventilation in 12 weeks, $CO_2$ within the bed reduced dramatically to 1.5%. In the cultivation shed the internal temperature was $7.1{\sim}29^{\circ}C$ and humidity was 27.3 to 100%, while bed temperature ranged $11.6{\sim}30^{\circ}C$. Oak mushroom fruiting started from late July, in 120 days after bed establishment in late March and continued for approximately 100 days until early December with eight cycles of irrigation treatment. The mushroom yield of the eight cycles were 288~352 kg during the 1st (7/29~8/4) to 3rd cycle (9/3~9/7), 800 kg at the 4th cycle (9/19~9/24), 1,296~1,853 kg during 5th (10/3~10/8) to 7th cycle (4.11~11/9) and 990 kg at 8th cycle (11/23~12/7). Total production was approximately 7.4 tons from 33.0 tons of oak sawdust medium, thus harvest efficiency of the mushroom production was approximately 22.4%.

• Journal of the Korean GEO-environmental Society
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• v.15 no.4
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• pp.5-11
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• 2014

Recently, there have been various lifeline installations constructed in the underground space of urban area due to the effective use of land. For newly installed lifelines or the management of the installed lifelines, many construction activities of excavation and backfilling are observed. Around these area, there are possibilities of collapse or excessive settlement due to the leaking of the pipe or unsatisfactory compaction of backfill material. Besides, construction costs can be saved since the on-site soils are used. The application of this liquidity filling material is not only to the lifeline installation but also to underpin the foundation under the vibrating machinery. On the evaluation of the applicability of this method to this circumstance, the strength should be investigated against the static load from the machine load as well as the vibration load from the activation of the machine. In this study, the applicability of the liquidity fill material on the foundation under the vibrating machinery is assessed via uniaxial compression and resonant column tests. The liquidity filling material consisting of the on-site soils with loess and kaolinite are tested to investigate the static and dynamic characteristics. Furthermore, the applicability of the reclaimed ash categorized as an industrial waste is evaluated for the recycle of the waste to the construction materials. The experimental results show that the shear modulus and 7 day uniaxial strength of the liquidity filling material mixed with reclaimed ash show higher than those with the on-site soils. However, the damping ratio does not show any tendency on the mixed materials.

• Journal of Bio-Environment Control
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• v.19 no.3
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• pp.140-146
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• 2010

This experiment was conducted to find the day and night temperature combination and the light-emitting diodes (LEDs) on the most effective globe coloration and growth of Chamecereus silvestrii f. variegata 'Hee-Mang'. The $L^*$value, $a^*$value and $b^*$value were all significant difference in the yellow globe color expression in the day and night temperature combination. Especially, the bright yellow color and visual value were the highest in the temperature combination, the day temperature of $20^{\circ}C$ and night temperature of $20^{\circ}C$. Globe color quality was lowered from the day temperature of $25^{\circ}C$ and night temperatures of $5^{\circ}C$ and $10^{\circ}C$ combination. In light-emitting diodes (LEDs) treatments, $a^*$value and $b^*$value are significant difference. A unique beautiful yellow coloration and globe quality were maintained the $a^*$value of +5.23, $b^*$value of +39.9 in a red LED. The optimum temperature range and light-emitting diodes (LEDs) on the globe color expression were the most effective the day temperature of 200e and night temperature of $20^{\circ}C$ and a red LED. In addition, the outer globe color quality of Chamecereus silvestrii f. variegata cultivation, rather than the light environment improvement is better in a proper temperature environment to keep. Especially, a unique globe color expression of yellow lines was most effective in a red LED.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.337-343
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• 2020

This study was carried out to evaluate the yield of cuttings according to the planting and runner releasing times of mother plants in order to raise the cutting seedlings of raising seedling period 75 days or more needed for forcing culture of strawberries to be transplanted into the field around the 15^th of September. Three domestic cultivars of 'Maehyang', 'Jukhyang', and 'Kuemsil' were tested. For experiment 1 to determine the yield of cuttings with the change of transplanting time, the mother plant were planted on February 28, March 20, and April 9 in 20 days intervals, and the cuttings were collected two to three times from June 4 to July 1. Experiment 2 was conducted to investigate the yield of cuttings depending on the runner releasing time, the runners were released in three intervals of 20 days, 40 days, and 60 days after planting the mother plant on March 5, and the cutting were collected once to three times from May 29 to June 26. From the comparisons of cutting yield according to the transplanting time of mother plants, February 28 treatment was more 9~25% and 114~165% for each cultivar than March 20 and April 9, respectively (Experiment 1). The yield of cuttings with releasing time 20 days after planting the mother plants had higher by 60~77% and 104~176% for each cultivar than 40 days and 60 days, respectively (Experiment 2). From these results, in case of propagating the seedlings from cuttings needed for field planting around September 15, early planting around in the latter part of February is the best for cuttings yield. In addition, releasing after the removal of the runners produced from mother plants by 20 days after planting gives an advantage over higher yield of cuttings. Consequently, this study suggest to apply an efficient raising seedling system for labor saving and quality improvement in raising seedlings of three strawberry cultivars in Korea.

• Asia pacific journal of information systems
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• v.19 no.2
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• pp.139-155
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• 2009

For the last few decades, many studies have tried to explore and unveil venture companies' success factors and unique features in order to identify the sources of such companies' competitive advantages over their rivals. Such venture companies have shown tendency to give high returns for investors generally making the best use of information technology. For this reason, many venture companies are keen on attracting avid investors' attention. Investors generally make their investment decisions by carefully examining the evaluation criteria of the alternatives. To them, credit rating information provided by international rating agencies, such as Standard and Poor's, Moody's and Fitch is crucial source as to such pivotal concerns as companies stability, growth, and risk status. But these types of information are generated only for the companies issuing corporate bonds, not venture companies. Therefore, this study proposes a method for evaluating venture businesses by presenting our recent empirical results using financial data of Korean venture companies listed on KOSDAQ in Korea exchange. In addition, this paper used multi-class SVM for the prediction of DEA-based efficiency rating for venture businesses, which was derived from our proposed method. Our approach sheds light on ways to locate efficient companies generating high level of profits. Above all, in determining effective ways to evaluate a venture firm's efficiency, it is important to understand the major contributing factors of such efficiency. Therefore, this paper is constructed on the basis of following two ideas to classify which companies are more efficient venture companies: i) making DEA based multi-class rating for sample companies and ii) developing multi-class SVM-based efficiency prediction model for classifying all companies. First, the Data Envelopment Analysis(DEA) is a non-parametric multiple input-output efficiency technique that measures the relative efficiency of decision making units(DMUs) using a linear programming based model. It is non-parametric because it requires no assumption on the shape or parameters of the underlying production function. DEA has been already widely applied for evaluating the relative efficiency of DMUs. Recently, a number of DEA based studies have evaluated the efficiency of various types of companies, such as internet companies and venture companies. It has been also applied to corporate credit ratings. In this study we utilized DEA for sorting venture companies by efficiency based ratings. The Support Vector Machine(SVM), on the other hand, is a popular technique for solving data classification problems. In this paper, we employed SVM to classify the efficiency ratings in IT venture companies according to the results of DEA. The SVM method was first developed by Vapnik (1995). As one of many machine learning techniques, SVM is based on a statistical theory. Thus far, the method has shown good performances especially in generalizing capacity in classification tasks, resulting in numerous applications in many areas of business, SVM is basically the algorithm that finds the maximum margin hyperplane, which is the maximum separation between classes. According to this method, support vectors are the closest to the maximum margin hyperplane. If it is impossible to classify, we can use the kernel function. In the case of nonlinear class boundaries, we can transform the inputs into a high-dimensional feature space, This is the original input space and is mapped into a high-dimensional dot-product space. Many studies applied SVM to the prediction of bankruptcy, the forecast a financial time series, and the problem of estimating credit rating, In this study we employed SVM for developing data mining-based efficiency prediction model. We used the Gaussian radial function as a kernel function of SVM. In multi-class SVM, we adopted one-against-one approach between binary classification method and two all-together methods, proposed by Weston and Watkins(1999) and Crammer and Singer(2000), respectively. In this research, we used corporate information of 154 companies listed on KOSDAQ market in Korea exchange. We obtained companies' financial information of 2005 from the KIS(Korea Information Service, Inc.). Using this data, we made multi-class rating with DEA efficiency and built multi-class prediction model based data mining. Among three manners of multi-classification, the hit ratio of the Weston and Watkins method is the best in the test data set. In multi classification problems as efficiency ratings of venture business, it is very useful for investors to know the class with errors, one class difference, when it is difficult to find out the accurate class in the actual market. So we presented accuracy results within 1-class errors, and the Weston and Watkins method showed 85.7% accuracy in our test samples. We conclude that the DEA based multi-class approach in venture business generates more information than the binary classification problem, notwithstanding its efficiency level. We believe this model can help investors in decision making as it provides a reliably tool to evaluate venture companies in the financial domain. For the future research, we perceive the need to enhance such areas as the variable selection process, the parameter selection of kernel function, the generalization, and the sample size of multi-class.