• Korean Journal of Soil Science and Fertilizer
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• v.27 no.2
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• pp.125-135
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• 1994

Field experiment was carried out in order to clarify effects of plastic film mulching on temperature and moisture of rhizosphere soil and their subsequent effects on seedling emergence, earlier growth, vegetative growth and grain yield of sesame. The textural class of the experimental field soil was the sandy loam(Bonyang series) and the variety of sesame planted was "Ansan-ggae". The experiment was conducted by combining four sowing dates of April 25, May 10, May 25, June 10 and two mulching treatments(mulching, non-mulching) over two year of 1991 and 1992. The results were summarized as follows : 1. The daily mean soil temperature of 5cm deep soil was increased by 1.4 to $2.8^{\circ}C$ by plastic film mulching. The average soil water content was increased by 0.5 to 3.0%(V/V) in the drier season, while decreased by 1.0 to 2.0%(V/V) in the rainy season by mulching. 2. The establishment rate of sesame seedling was very sensitive to soil temperature. For normal seedling emergence, from the seeding date to the 7th date after sowing, the daily mean soil temperature higher than $21.0^{\circ}C$ was required at the experimental field conditions. 3. The average soil water content in the range of 14.0 to 21.0%(V/V) at 5cm deep soil seemed not to be limiting for the germination and emergence of sesame. The effect of soil water content on seedling establishment was very small in this range, but the optimum level of soil water content ranged from 14.0 to 15.0%(V/V) in the experimented sandy loam. 4. The wetter the soil profile was, the larger the gap of soil temperature between the mulched and non-mulched condition was. The effect of mulching on the establishment rate of sesame seedlings was much greater in the lower air temperature conditions. However, when the sowing of sesame came earlier than at the date with the daily mean air temperature below $19.0^{\circ}C$, the effects of earlier sowing and mulching were offsetted by the retarded seedling growth due to the low air temperature, and thus earlier sowing with mulching did not enhance the grain yield of sesame.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.2
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• pp.203-209
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• 2009

Yield monitoring is one of a precision agriculture technology that is used most widely. It is spatial variability analysis of yield information that should be attained with yield monitoring system development. This experiment was conducted to evaluate spatial variability of yield and grain moisture content in rice paddy field, and their relationships to rice productivity. It is necessary to minimize sampling interval for accurate yield map making or to control cutting width of rice combine. Considering small rice plots such as $0.2{\sim}0.4$ ha, optimum size of sampling plot was below 15 m more than 5 m in with and length. In variable rate treatment field, average yield was similar, but yield variation was reduced than conventional field. Gap of yield by another plot in same field was bigger than half of average yield than yield variation was significantly big. Therefore yield measuring flow sensor must be able to measure at least 300 kg/10a more than 1000 kg/10a. Variation of moisture content in same field was not big and spatial dependance did not appear greatly. But, variation between different field is appeared difference according to weather circumstance before harvesting. Change of spatial dependence of yield was not big, because of field variation of moisture content is not big.

• Journal of Korean society of Dental Hygiene
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• v.7 no.2
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• pp.135-151
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• 2007

The purpose of this study was to examine the work environments of dental hygienists, to find out about what problems there were with their work environments and ultimately to help improve their work environments. It's basically intended to pave the way for furthering the welfare and interests of dental hygienists. The subjects in this study were dental hygienists who were selected by random sampling from among the members of Korean Dental Hygienists Association. Approximately 20 percent of the members each were selected from every region across the nation, and their work environments were investigated in consideration of the kind of their workplaces, service area, career and field of duties. As for the demographic characteristics of the dental hygienists investigated, there were differences between those who worked in the field of health care and the clinical workers. More of the former were older and married, and the former was ahead of the latter in career and education as well. Regarding working hours and leave of absence by kind of workplace, the number of regular average holidays was different according to their place of employment. Dental hospitals(6.66 days) and dental clinics(6.81 days) gave their employees less days off on the whole, whereas public dental clinics(19.29 days) granted the dental hygienists the longest leave of absence. Also, there was a broad gap in the number of regular average holidays among different regions in the nation. The dental hygienists who worked in Gangweon province enjoyed the longest holidays(10.88 days), while those on Jeju Island took the shortest vacation(4.46 days). Concerning monthly mean pay by place of employment, those who worked in public dental clinics were paid the best, and the dental hospital employees received the smallest pay. Their monthly mean pay significantly varied with the kind of their workplaces. As to connections between service area and pay level in the event of the dental hygienists with a four-year career, those who served in Seoul were paid the best(1,820,800 won), followed by Gyeonggi province(1,795,800 won), Gyeongsang province(1,604,200 won), metropolitan cities(1,424,800), Gangweon province(1,300,000 won) and Jeolla province(1,016,700 won). In regard to the starting pay in the different areas, the starting pay was largest in Seoul(1,501,800 won) and smallest in Jeolla province(904,000 won). Concerning work environments by place of employment, the dental hygienists in public dental clinics, general hospitals and university hospitals were far older than the others, and the career of the former was much larger than that of the latter. As to the number of regular leave of absence, public dental clinics, general hospitals and university hospitals were different from dental hospitals and clinics in that regard as well. Concerning monthly pay, public dental clinics paid their employees the best, and dental hospitals and clinics were ahead in terms of pay raise. But the reason seemed that public dental clinics and general hospitals increased the pay of their employees based on a fixed wage system and according to a fixed rate at the same time. As for relations between career and work environments, the pay of the dental hygienists differed with their career. The amount and rate of pay raise were largest for those whose career was between four years and less than six years, and smallest for those whose career was between seven years and less than nine years. The above-mentioned findings of the study suggested that in order to give dental hygienists better treatment, pay and welfare benefits should urgently be improved, and that it's required to take actions to boost their job satisfaction. Besides, they should be given more chances to receive education or to take training courses in pursuit of self-development, and how to narrow gaps in work environments among different regions or fields should carefully be considered.

• Asia pacific journal of information systems
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• v.20 no.3
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• pp.191-204
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• 2010

Recently, the CO2 emission and energy consumption have become critical global issues to decide the future of nations. Especially, the spread of IT products and the increased use of internet and web applications result in the energy consumption and CO2 emission of IT industry though information technologies drive global economic growth. EU, the United States, Japan and other developed countries are using IT related environmental regulations such as WEEE(Waste Electrical and Electronic Equipment), RoHS(Restriction of the use of Certain Hazardous Substance), REACH(Registration, Evaluation, Authorization and Restriction of CHemicals) and EuP(Energy using Product), and have established systematic green business/IT strategies to enhance the competitiveness of IT industry. For example, the Japan government proposed the "Green IT initiative" for being compatible with economic growth and environmental protection. Not only energy saving technologies but energy saving systems have been developed for accomplishing sustainable development. Korea's CO2 emission and energy consumption continuously have grown at comparatively high rates. They are related to its industrial structure depending on high energy-consuming industries such as iron and steel Industry, automotive industry, shipbuilding industry, semiconductor industry, and so on. In particular, export proportion of IT manufacturing is quite high in Korea. For example, the global market share of the semiconductor such as DRAM was about 80% in 2008. Accordingly, Korea needs to establish a systematic strategy to respond to the global environmental regulations and to maintain competitiveness in the IT industry. However, green competitiveness of Korea ranked 11th among 15 major countries and R&D budget for green technology is not large enough to develop energy-saving technologies for infrastructure and value chain of low-carbon society though that grows at high rates. Moreover, there are no concrete action plans in Korea. This research aims to deduce the priorities of the Korean green business/IT strategies to use multi attribute weighted average method. We selected a panel of 19 experts who work at the green business related firms such as HP, IBM, Fujitsu and so on, and selected six assessment indices such as the urgency of the technology development, the technology gap between Korea and the developed countries, the effect of import substitution, the spillover effect of technology, the market growth, and the export potential of the package or stand-alone products by existing literature review. We submitted questionnaires at approximately weekly intervals to them for priorities of the green business/IT strategies. The strategies broadly classify as follows. The first strategy which consists of the green business/IT policy and standardization, process and performance management and IT industry and legislative alignment relates to government's role in the green economy. The second strategy relates to IT to support environment sustainability such as the travel and ways of working management, printer output and recycling, intelligent building, printer rationalization and collaboration and connectivity. The last strategy relates to green IT systems, services and usage such as the data center consolidation and energy management, hardware recycle decommission, server and storage virtualization, device power management, and service supplier management. All the questionnaires were assessed via a five-point Likert scale ranging from "very little" to "very large." Our findings show that the IT to support environment sustainability is prior to the other strategies. In detail, the green business /IT policy and standardization is the most important in the government's role. The strategies of intelligent building and the travel and ways of working management are prior to the others for supporting environment sustainability. Finally, the strategies for the data center consolidation and energy management and server and storage virtualization have the huge influence for green IT systems, services and usage This research results the following implications. The amount of energy consumption and CO2 emissions of IT equipment including electrical business equipment will need to be clearly indicated in order to manage the effect of green business/IT strategy. And it is necessary to develop tools that measure the performance of green business/IT by each step. Additionally, intelligent building could grow up in energy-saving, growth of low carbon and related industries together. It is necessary to expand the affect of virtualization though adjusting and controlling the relationship between the management teams.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1982.05a
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• pp.14.2-15
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• 1982

Serous otitis media (SOM) is one of the most common otologic diseases which was first discribed by Politzer in 1869. Currentely, among many methods introduced to treat SOM, ventilation tube insertion is considered to be the most popular and standard method being used. However due to complication of it, there remains many disputable various problems. In order to review the clinical aspect of SOM and search for the effects and safety of ventilation tube, we studied 97 SOM patients, who had performed V-tube from Jan. 1981 to Feb. 1982 at ENT dept. of Severance Hospital. Analizing the clinical symptoms, age distribution, associated disease, otoscopic findings of ear drum, degree of hearing loss, hearing gain after insertion of V-tube and complications, following results were obtained. 1) As a subjective symptom, among 29 cases all patients had hearing loss, 19 cases (65.6%) had tinnitus, 12 cases (44.4%) had autophony and 10 cases (34.5%) of the patients had sensation of ear fullness. 2) In age distribution, 6 to 10 year old group was most numerous up to 42 cases (43.3%) and 20 years and over was 23 cases (23.5%) 3) In adult group SOM tend to be involved unilaterally whereas young child group had tendency involving bilaterally. 4) 49 cases (50.05%) were associated with tonsillitis and adenoid vegetation, 15 cases (15.5%) were associated with sinusitis, 4 cases (4.1%) had nasal allergy. 5) In preoperative otoscopic findings, 62 ears (47.7%) had retraction, 37 ears (23.6%) had bulging, 34 ears (21.7%) had color change, and 29 ears (19.7%) had no significant findings. 6) In characteristics of middle ear fluid, child group was tend to have mucinous content (84.2%) while adult group had serous content (62.5%). 7) Average preoperative air-bone gap of pure tone was 25.3 dB. 8) 24 ears (72.7%) had over 10 dB of postoperative hearing gain and average hearing gain was 17.2 dB. 9) There were 44 ears (28.1%) of complications. Among them 37 ears (23.6%) had infection, 3 ears had atelectasis, 2 ears had granulation tissue, 2 ears had permanent perforations. 10) Among 37 ears suffered from post-op. infection, 19 ears (51.4%) had initial infection just after insertion of ventilation tube, 18 ears (48.6%) were infected during the course of post-ventilation tube. Of 37 infected ears, 26 ears (70.3%) responded to conservative care, while 11 ears (29.7%) was cured after removal of ventilation tube.

• Journal of Magnetics
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• v.20 no.4
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• pp.381-386
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• 2015

The purpose of this study is to improve diagnostic efficiency of clinical study by setting up guidelines for more precise examination with a comparative analysis of signal intensity and image distortion depending on the location of X axial of object when performing magnetic resonance diffusion weighted imaging (MR DWI) examination. We arranged the self-produced phantom with a 45 mm of interval from the core of 44 regent bottles that have a 16 mm of external diameter and 55 mm of height, and were placed in 4 rows and 11 columns in an acrylic box. We also filled up water and margarine to portrait the fat. We used 3T Skyra and 18 Channel Body array coil. We also obtained the coronal image with the direction of RL (right to left) by using scan slice thinkness 3 mm, slice gap: 0mm, field of view (FOV): $450{\times}450mm^2$, repetition time (TR): 5000 ms, echo time (TE): 73/118 ms, Matrix: $126{\times}126$, slice number: 15, scan time: 9 min 45sec, number of excitations (NEX): 3, phase encoding as a diffusion-weighted imaging parameter. In order to scan, we set b-value to $0s/mm^2$, $400s/mm^2$, and $1,400s/mm^2$, and obtained T2 fat saturation image. Then we did a comparative analysis on the differences between image distortion and signal intensity depending on the location of X axial based on iso-center of patient's table. We used "Image J" as a comparative analysis programme, and used SPSS v18.0 as a statistic programme. There was not much difference between image distortion and signal intensity on fat and water from T2 fat saturation image. But, the average value depends on the location of X axial was statistically significant (p < 0.05). From DWI image, when b-value was 0 and 400, there was no significant difference up to $2^{nd}$ columns right to left from the core of patient's table, however, there was a decline in signal intensity and image distortion from the $3^{rd}$ columns and they started to decrease rapidly at the $4^{th}$ columns. When b-value was 1,400, there was not much difference between the $1^{st}$ row right to left from the core of patient's table, however, image distortion started to appear from the $2^{nd}$ columns with no change in signal intensity, the signal was getting decreased from the $3^{rd}$ columns, and both signal intensity and image distortion started to get decreased rapidly. At this moment, the reagent bottles from outside out of 11 reagent bottles were not verified from the image, and only 9 reagent bottles were verified. However, it was not possible to verify anything from the $5^{th}$ columns. But, the average value depends on the location of X axial was statistically significant. On T2 FS image, there was a significant decline in image distortion and signal intensity over 180mm from the core of patient's table. On diffusion-weighted image, there was a significant decline in image distortion and signal intensity over 90 mm, and they became unverifiable over 180 mm. Therefore, we should make an image that has a diagnostic value from examinations that are hard to locate patient's position.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.2
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• pp.209-218
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• 2005

The purpose of this study was to evaluate the students' satisfaction with the Quality of middle school foodservice in Busan area. For purpose, Questionnaires were distributed to 788 students in 8 middle schools (four schools for classroom service, four schools for restaurant service). The average scores were -1.13 for gap of meal, -1.68 for sanitation, -1.19 for menu, -1.63 for attitude of foodservice staffs, and -0.89 for rapidity and exactness of service. The whole students assessed the important and performance of school food service 4.20/5.00 and 2.99/5.00. The restaurant service had significantly (p<0.01) higher average scores performance of meal, sanitation, and rapidity and exactness of service than those of the class room service. The Importance-Performance Analysis (IPA) gride, high importance and low performance (focus here) were cleanliness of dish, cleanliness restoration area, rapid treatment about complaints, reflection students' opinions, and listening to students' opinions in the classroom service and the restaurant service, but the Quality vs. price of meal, sanitation of meal, and dessert supply were included in focus here part in the classroom service.

• Journal of dental hygiene science
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• v.10 no.5
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• pp.403-409
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• 2010

The purpose of this study was to examine the teaching efficiency of clinical training for dental hygiene students in Gyeonggi Province. The subjects in this study were 371 dental hygiene juniors in seven different colleges in Gyeonggi Province, on whom a self-administered survey was conducted. The collected data were analyzed with a SPSS WIN 12.0 program, and the findings of the study were as follows: 1. The teaching efficiency of clinical training that the dental hygiene students undergone was on the average. As for evaluation of the factors of teaching efficiency, they gave the highest marks to the role model factor(3.40). 2. The size of the institutions where they received clinical training made no statistically significant differences to the teaching efficiency of their clinical training. The university hospitals ranked first in professional knowledge, one of the sub-directory of teaching efficiency, and the gap between them and the others was statistically significant(p=.005). 3. Concerning links between satisfaction level with the major and view of teaching efficiency, stronger satisfaction with the major led to better perception of teaching efficiency(p=.001). Among the subdirectory of teaching efficiency, that made statistically significant differences to view of interpersonal skills, performance as a supporter, fair evaluation, academic organization skills(p=.005), encouragement and support, teaching methods, professional academic knowledge(p=.001), communicative competency, performance as a role model and cooperation with the staff of dental clinics(p=.000). 4. There were no statistically significant gaps in teaching efficiency according to teaching styles. Among the sub-directory of teaching efficiency, statistically significant differences were found only in encouragement and support(p=.005). The above-mentioned findings suggest that the teaching efficacy of the clinical training was approximately on the average, and that a better satisfaction with the major led to a higher teaching efficacy. Therefore a wide variety of teaching methods and systematic training programs should be developed to boost the quality of clinical training to improve its teaching efficacy.

• Asia pacific journal of information systems
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• v.24 no.4
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• pp.493-513
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• 2014

With the development of related technologies, Location-Based Services (LBS) are growing fast and being used in many ways. Past LBS studies have focused on adoption of LBS because of the fact that LBS users have privacy concerns regarding revealing their location information. Meanwhile, the number of LBS users and revenues from LBS are growing rapidly because users can get some benefits by revealing their location information. Little research has been done on how LBS affects consumers' information search behavior in product purchase. The purpose of this paper is examining the effect of LBS information filtering on buyers' uncertainty and their information search behavior. When consumers purchase a product, they try to reduce uncertainty by searching information. Generally, there are two types of uncertainties - knowledge uncertainty and choice uncertainty. Knowledge uncertainty refers to the lack of information on what kinds of alternatives are available in the market and/or their important attributes. Therefore, consumers having knowledge uncertainty will have difficulties in identifying what alternatives exist in the market to fulfil their needs. Choice uncertainty refers to the lack of information about consumers' own preferences and which alternative will fit in their needs. Therefore, consumers with choice uncertainty have difficulties selecting best product among available alternatives.. According to economics of information theory, consumers narrow the scope of information search when knowledge uncertainty is high. It is because consumers' information search cost is high when their knowledge uncertainty is high. If people do not know available alternatives and their attributes, it takes time and cognitive efforts for them to acquire information about available alternatives. Therefore, they will reduce search breadth. For people with high knowledge uncertainty, the information about products and their attributes is new and of high value for them. Therefore, they will conduct searches more in-depth because they have incentive to acquire more information. When people have high choice uncertainty, people tend to search information about more alternatives. It is because increased search breadth will improve their chances to find better alternative for them. On the other hand, since human's cognitive capacity is limited, the increased search breadth (more alternatives) will reduce the depth of information search for each alternative. Consumers with high choice uncertainty will spend less time and effort for each alternative because considering more alternatives will increase their utility. LBS provides users with the capability to screen alternatives based on the distance from them, which reduces information search costs. Therefore, it is expected that LBS will help users consider more alternatives even when they have high knowledge uncertainty. LBS provides distance information, which helps users choose alternatives appropriate for them. Therefore, users will perceive lower choice uncertainty when they use LBS. In order to test the hypotheses, we selected 80 students and assigned them to one of the two experiment groups. One group was asked to use LBS to search surrounding restaurants and the other group was asked to not use LBS to search nearby restaurants. The experimental tasks and measures items were validated in a pilot experiment. The final measurement items are shown in Appendix A. Each subject was asked to read one of the two scenarios - with or without LBS - and use a smartphone application to pick a restaurant. All behaviors on smartphone were recorded using a recording application. Search breadth was measured by the number of restaurants clicked by each subject. Search depths was measured by two metrics - the average number of sub-level pages each subject visited and the average time spent on each restaurant. The hypotheses were tested using SPSS and PLS. The results show that knowledge uncertainty reduces search breadth (H1a). However, there was no significant correlation between knowledge uncertainty and search depth (H1b). Choice uncertainty significantly reduces search depth (H2b), but no significant relationship was found between choice uncertainty and search breadth (H2a). LBS information filtering significantly reduces the buyers' choice uncertainty (H4) and reduces the negative relationship between knowledge uncertainty and search breadth (H3). This research provides some important implications for service providers. Service providers should use different strategies based on their service properties. For those service providers who are not well-known to consumers (high knowledge uncertainty) should encourage their customers to use LBS. This is because LBS would increase buyers' consideration sets when the knowledge uncertainty is high. Therefore, less known services have chances to be included in consumers' consideration sets with LBS. On the other hand, LBS information filtering decrease choice uncertainty and the near service providers are more likely to be selected than without LBS. Hence, service providers should analyze geographically approximate competitors' strength and try to reduce the gap so that they can have chances to be included in the consideration set.

• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1739-1756
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• 2021

Atmospheric nitrogen dioxide (NO₂) is mainly caused by anthropogenic emissions. It contributes to the formation of secondary pollutants and ozone through chemical reactions, and adversely affects human health. Although ground stations to monitor NO₂ concentrations in real time are operated in Korea, they have a limitation that it is difficult to analyze the spatial distribution of NO₂ concentrations, especially over the areas with no stations. Therefore, this study conducted a comparative experiment of spatial interpolation of NO₂ concentrations based on two linear-regression methods(i.e., multi linear regression (MLR), and regression kriging (RK)), and two machine learning approaches (i.e., random forest (RF), and support vector regression (SVR)) for the year of 2020. Four approaches were compared using leave-one-out-cross validation (LOOCV). The daily LOOCV results showed that MLR, RK, and SVR produced the average daily index of agreement (IOA) of 0.57, which was higher than that of RF (0.50). The average daily normalized root mean square error of RK was 0.9483%, which was slightly lower than those of the other models. MLR, RK and SVR showed similar seasonal distribution patterns, and the dynamic range of the resultant NO₂ concentrations from these three models was similar while that from RF was relatively small. The multivariate linear regression approaches are expected to be a promising method for spatial interpolation of ground-level NO₂ concentrations and other parameters in urban areas.