• Journal of the Korean Chemical Society
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• v.58 no.6
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• pp.590-599
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• 2014

Environmental education, effectively performed at school, is very important to solve the environmental problems. Moreover the survey for teacher's perception is essential. The purpose of the study was to investigate the perception of environmental problems of middle school teachers in Pusan. The survey was done twice in 2007 and 2012, and based on the time intervals, careers, and major of the teachers. 200 teachers were chosen in 2007 and 300 teachers in 2012. How many environmental problems occurred during this time period affected the 471 teachers' perception was investigated and analyzed. The results are as follows. First, the perception difference of environmental problems was meaningful between two time intervals (p<.01). Especially, the perception of modern environmental problems and carbon emission showed considerable increase in both science and non-science major teachers. This may be caused by the climate change and the severity of lifestyles of indiscriminate consumerism. Second, the perception difference of environmental problems by careers was also meaningful (p<.01). Overall, the perception was obvious on the aspects of modern environmental problems, carbon emission, destruction of ozone layers, nuclear wastes, environmental hormones, and red tides. Teachers, having more careers irrespective of their teaching subjects, showed higher perception on the seriousness of environmental pollution, the necessity of environmental conservation, and the importance of health. Third, the perception of environmental problems between science and non-science major teachers was meaningful (p<.01). Particularly, the perception in the broad environmental problems was distinctive between them.

• Korean Journal of Plant Resources
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• v.31 no.5
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• pp.515-521
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• 2018

This was carried out to develop a chromosome-doubled (12x) persimmon that will be used as a crossing parent to select seedless persimmon cultivars with the change of the consumption trend recently. To obtain a chromosome-doubled (12x) persimmon, colchicine was applied at the meristem of seedlings in vitro derived from cross among hexaploid persimmon (Diopyros kaki Thunb.). These were treated with 0.03%, 0.05% and 0.1% colchicine respectively for doubling chromosome, and it was most effective at the concentration of 0.05% colchicine. After colchicine treatment, we conducted tests to elucidate conditions for inducing shoot and root development. As the result, the shoots grew best when cultivated at 1/2MS media plus 10 and $30{\mu}M$ zeatin respectively, and the roots grew best when cultivated at 1/2MS media after dipping for 5 seconds at 10 mM NAA+5% DMSO. We also compared seedlings that have chromosome (6x) do not doubled and crossing parents (6x) and chromosome-doubled seedlings (12x). As the result, these chromosome-doubled seedlings (12x) showed lower stomatal density and larger stomatal size.

• Korean Journal of Ecology and Environment
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• v.34 no.4 s.96
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• pp.261-266
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• 2001

Effects of elevated carbon dioxide ($CO_2$) on soil microbial processes were studied in a northern peatland. Intact peat cores with surface vegetation were collected from a northern Welsh fen, and incubated either under elevated carbon dioxide (700 ppm) or ambient carbon dioxide (350 ppm) conditions for 4 months. Higher algal biomass was found under the elevated $CO_2$ condition, suggesting $CO_2$ fertilization effect on primary production, At the end of the incubation, trace gas production and consumption were analyzed using chemical inhibitors. For methane ($CH_4$ ), methyl fluoride ($CH_3F$) was applied to determine methane oxidation rates, while acetylene ($C_2H_2$) blocking method were applied to determine nitrification and denitrification rates. First, we have adopted those methods to optimize the reaction conditions for the wetland samples. Secondly, the methods were applied to the samples incubated under two levels of $CO_2$. The results exhibited that elevated carbon dioxide increased both methane production (210 vs. $100\;ng\;CH_4 g^{-1}\;hr^{-1}$) and oxidation (128 vs. $15\;ng\;CH_4 g^{-1}\;hr^{-1}$), resulting in no net increase in methane flux. For nitrous oxide ($N_2O$) , elevated carbon dioxide enhanced nitrous oxide emission probably from activation of nitrification process rather than denitrification rates. All of these changes seemed to be substantially influenced by higher oxygen diffusion from enhanced algal productivity under elevated $CO_2$.

• Korea Journal of Hospital Management
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• v.3 no.1
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• pp.192-218
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• 1998

This study is the positive one about the influence which the characteristics of medical consumers' perceived words-transmission information exercises on its acceptance level and its activities. The aim of this study was to investigate how the characteristics-reliability of perceived information, its directionity, and its availability-had an influence on the acceptance level and activities of words-transmission information. For the purpose of that aim, the positive research by questionnaire was applied. In addition, to collect necessary data, investigation was performed about 20 days from July 1st, 1938 to July 20th, 1938. As for the respondents' sampling in sample planning, the method of Simple Random Sampling was used laying stress on patients or their responsible person aged over 20s in second and third medical institutions. And the collected sample were 230 people. Of these, However, the number of sample used actually for this study analysis was 211 except 19 people who responded unfaithfully. The analysis of the data collected by the abovesaid investigation used SPSS/PC statistical package. The study result to have proved the hypothesis by experiment is as follows. First, as the result of having analysed the influence relations on the acceptance level and activities of words-transmission information among the factors of reliability about medical consumers' perceived information, I found that 'specialty' had an affirmative effect and there was a significant effect relations. Second, as the result of having made a multi-regression analysis of the effect relations on the acceptance level and activities of words-transmission information of the factors of directionity on medical consumers' perceived information, 'reliablity' was found as having a significant effect on the acceptance of words-transmission information. Third, 'importantness' was revealed as having a significant effect on the words-transmission activities in the acceptance level and activities of words-transmission information among the factors of reliability on medical consumers' perceived information. Fourth. for medical consumers there was a statistical correlation between the acceptance level and activities of words-transmission information. Therefore, words-transmission communication will be very useful for hospital promotion programs having a limited advertising ability in business. Especially, I suggest that a person in charge of his/her hospital marketing should not only excavate a source of words-transmission communication in order to arrive effectively at sampling market, but also use a marketing mix suitable to that The test result shows that the unsatisfied patients over their hospital treatment tend to be more stronger in transmitting words to the other positive minded patients than the satisfied ones. Therefore, all relating representatives in hospital should concentrate their energies on decreasing or eliminating these unwanted results.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.8
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• pp.1236-1241
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• 2013

This study was conduct in order to provide information on formula optimization, salinity, and water content for commercialization of traditional buckwheat Soksungjang. To do this, we determined quality characteristics such as total microbial flora counts, amino-type nitrogen content, total polyphenol content, antioxidant activity, and performed a sensory evaluation. The moisture contents showed a gradual decrease during the fermentation period. There was no significant difference in all samples. During 70 days of fermentation, the pH showed a similar trend starting at a pH of 6, and dropping sharply to 5.5, except Experiment C (15% buckwheat powder in the meju, 10% NaCl, and 130% water in the total Soksungjang). On the other hand, total acidity increased regularly, however, its ranges were various points in all samples. The microbial population was reduced by 1~3 log cycle in all samples during the fermentation period. The content of amino-type nitrogen showed a gradual increase during fermentation, ranging from 160 to 213 mg% after 70 days. No remarkable difference in total polyphenol content and antioxidant activity was observed in all samples. In sensory evaluation, Soksungjang with 30% (control) and 15% (Experiment C) buckwheat showed a significantly higher overall score.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.1
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• pp.21-30
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• 1991

In Summer, oxygen-deficient water masses were developed extensively in the closed eutrophic bays such as Chinhae Bay which results in mass mortality of marine organisms and severe decrease the production of the bay every year. Under the circumstances, this study was performed to investigate the oxygen depletion relating to eutrophication, and also to evaluate self-purfication capacity of Buk Bay by dissolved oxygen mass balance in 1988. The mean concentration of total inorganic nitrogen, phosphate phosphorus and chlorophyll-a were $11.06{\mu}g-at/l,\;0.80{\mu}g-at/l\;and\;1.11mg/m^3$ respectively, which were over eutrophication criteria. Oxygen-deficient water mass was formed in July with the minimum concentration of 2.08ml/l(mean) at the bottom of all stations and recovered slowly in August. The decay and reaeration coefficient calculated from dissloved oxygen sag curve were 0.222/day and 0.018ml/l/day, respectively. To maintain above 4ml/l of oxygen to prevent oxygen-deficient water mass, it is recommendable to supply as much as 0.856ml/l/day of dissolved oxygen or should be reduced the same mass loading of BOD from watershed by the construction of wastewater treatment plant.

• The Journal of the Korea Contents Association
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• v.16 no.3
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• pp.354-365
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• 2016

The purpose of the study was to identify and compare levels of recognition of empowerment, job satisfaction, organizational commitment between Advanced Practice Nurses(APN) and Registered Nurses(RN) of hospitals. Data collection was done by the 85 APN and 120 RN of six large hospitals, four medium sized hospitals in Seoul and Incheon. T-test and ANOVA using SPSS 18.0 were performed. There were no significant differences of empowerment between APN($3.56{\pm}0.53$) and RN($3.50{\pm}0.54$)(t =-. 861, p = 0.390). job satisfaction between APN($3.36{\pm}0.53$) and RN($3.25{\pm}0.46$)(t =- 1.575, p = 0.117), organizational commitment between APN($3.11{\pm}0.34$) and RN($3.05{\pm}0.36$)(t =- 1.301, p = 0.195). Empowerment, job satisfaction, organizational commitment of APN and RN showed no significant differences. There are some reasons why it resulted in no significant difference between APN and RN. APN's role in Korea is not clearly established and distinguished from RN, lack of appropriacy of employment and reward, and lack of the institutional foundation for APN's operation and efficiency.

• Journal of Broadcast Engineering
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• v.25 no.1
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• pp.94-104
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• 2020

Currently media consumption over fixed/mobile Internet is mostly conducted by adaptive media streaming technology such as DASH (Dynamic Adaptive Streaming over HTTP), which is an ISO/IEC MPEG (Moving Picture Experts Group) standard, or some other technologies similar to DASH. All these heavily depend on the HTTP caches that ISPs (Internet Service Providers) are obliged to provide sufficiently to make sure fast enough Web services. As a result, as the number of media streaming users increases, ISPs' burden for HTTP cache has been greatly increased rather than CDN (Content Delivery Network) providers' server burden. Hence ISPs charge traffic cost to CDN providers to compensate for the increased cost of HTTP caches. Recently in order to reduce the traffic cost of CDN providers, P2P (Peer-to-Peer)-assisted DASH system was proposed and a peer selection algorithm that maximally reduces CDN provides' traffic cost was investigated for this system. This algorithm, however, tends to concentrate the burden upon the selected peer. This paper proposes a new peer selection algorithm that distributes the burden among multiple peers while maintaining the proper reduction level of the CDN providers' cost. Through implementation of the new algorithm in a Web-based media streaming system using WebRTC (Web Real-Time Communication) standard APIs, it demonstrates its effectiveness with experimental results.

• Journal of Bio-Environment Control
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• v.21 no.2
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• pp.153-161
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• 2012

This study was conducted to investigate the chlorophyll contents, photosynthetic characteristics and chlorophyll fluorescence of Cirsium setidens and Pleurospermum camtschaticum by shading treatment. Two species were grown under non-treated (full sunlight) and three different shading condition (88~93%, 65~75% and 45%~55% of full sunlight) for the experiment. Total chlorophyll content, photochemical efficiency (Fv/Fm), specific leaf area (SLA), and net apparent quantum yield were increased with elevating shading level but decreased dark respiration under the low light intensity. Therefore, light absorption and light utilization efficiency were improved under the low light intensity. 45~55% of full sunlight in C. setidens and 65~75% of full sunlight in P. camtschaticum showed best maximum photosynthetic rate, net apparent quantum yield and photochemical efficiency. On the other hand, non-treated showed lower maximum photosynthetic rate, photochemical efficiency, and chlorophyll content than treated ones. These results suggest that growth of P. camtschaticum adapted to 65~75% of full sunlight and C. setidens adapted to 45~55% of full sunlight.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.728-734
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• 2016

The improvements of living and lifestyle have led to the increased sales of frozen milk products, such as soft ice cream or slush. These frozen milk products are commonly made in small refrigeration machines. R-502, which has long been used as the refrigerant in soft ice cream machines, is being replaced with R-404A due to the ozone layer depletion issue. In this study, an optimization and performance evaluation were conducted on a soft ice cream machine with a freezer volume of 2.8 liters. The optimization focused on the appropriate refrigerant charge and expansion valve opening. Under the optimized conditions, ice cream was produced in 10 minutes and 5 seconds, and the COP was 0.57. The performance tests included ice cream sales with no interval, ice cream sales with 30 second intervals and under extreme outdoor conditions. The results showed that 20 sales were possible with no interval, and infinite sales could be made with 30 seconds intervals. Ice cream sales were also possible under summer or winter outdoor conditions. The present results may be used for the design of food refrigeration machines as well as to optimize other refrigeration cycles.