• Korean Journal of Environment and Ecology
• /
• v.33 no.5
• /
• pp.605-619
• /
• 2019

The objective of this study was to analyze eutrophication characteristics, empirical model analysis, and variation of water quality according to monsoon intensity in Hapcheon Reservoir for 16 years from 2002 to 2017. Long-term annual water quality analysis showed that Hapcheon Reservoir was in a meso-nutrition to eutrophic condition, and the eutrophic state intensified after the summer monsoon. Annual rainfall volume (high vs. low rainfall) and the seasonal intensity in each year were the key factors that regulate the long-term water quality variation provided that there is no significant change of the point- and non-point source in the watershed. Dry years and wet years showed significant differences in the concentrations of TP, TN, BOD, and conductivity, indicating that precipitation had the most direct influence on nutrients and organic matter dynamics. Nutrient indicators (TP, TN), organic pollution indicators (BOD, COD), total suspended solids, and chlorophyll-a (Chl-a), which was an estimator of primary productivity, had significant positive relations (p<0.05) with precipitation. The Chl-a concentration, which is an indicator of green algae, was highly correlated with TP, TN, and BOD, which differed from other lakes that showed the lower Chl-a concentration when nutrients increased excessively. Empirical model analysis of log-transformed TN, TP, and Chl-a indicated that the Chl-a concentration was linearly regulated by phosphorus concentration, but not by nitrogen concentration. Spatial regression analysis of the riverine, transition, and lacustrine zones of $log_{10}TN$, $log_{10}TP$, and $log_{10}CHL$ showed that TN and Chl-a had significant relations (p<0.005) while TN and Chl-a had p > 0.05, indicating that phosphorus had a key role in the algal growth. Moreover, the higher correlation of both $log_{10}TP$ and $log_{10}TN$ to $log_{10}CHL$ in the riverine zone than the lacustrine zone indicated that there was little impact of inorganic suspended solids on the light limitation in the riverine zone.

• Korean Journal of Environmental Agriculture
• /
• v.37 no.4
• /
• pp.268-276
• /
• 2018

BACKGROUND: In the month of January 2018, fine dust alerts and warnings were issued 36 times for $PM_{10}$ and 81 times for PM2.5. Air quality is becoming a serious issue nation-wide. Although interest in air-purifying plants is growing due to the controversy over the risk of chemical substances of regular air-purifying solutions, industrial spread of the plants has been limited due to their efficiency in air-conditioning perspective. METHODS AND RESULTS: This study aims to propose a vegetation-based bio-filter system that can assure total indoor air volume for the efficient application of air-purifying plants. In order to evaluate the quantitative performance of the system, time-series analysis was conducted on air-conditioning performance, indoor air quality, and comfort index improvement effects in a lecture room-style laboratory with 16 persons present in the room. The system provided 4.24 ACH ventilation rate and reduced indoor temperature by $1.6^{\circ}C$ and black bulb temperature by $1.0^{\circ}C$. Relative humidity increased by 24.4% and deteriorated comfort index. However, this seemed to be offset by turbulent flow created from the operation of air blowers. While $PM_{10}$ was reduced by 39.5% to $22.11{\mu}g/m^3$, $CO_2$ increased up to 1,329ppm. It is interpreted that released $CO_2$ could not be processed because light compensation point was not reached. As for the indoor comfort index, PMV was reduced by 83.6 % and PPD was reduced by 47.0% on average, indicating that indoor space in a comfort range could be created by operating vegetation-based bio-filters. CONCLUSION: The study confirmed that the vegetation-based bio-filter system is effective in lowering indoor temperature and $PM_{10}$ and has positive effects on creating comfortable indoor space in terms of PMV and PPD.

• Journal of the Korean Applied Science and Technology
• /
• v.35 no.4
• /
• pp.1108-1119
• /
• 2018

As the interest on the air pollution is gradually rising at home and abroad, automotive and fuel researchers have been studied on the exhaust and greenhouse gas emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative after-treatment systems, using clean (eco-friendly alternative) fuels and fuel quality improvement. This research has brought forward two main issues : exhaust emissions (regulated and non-regulated emissions, PM particle matter) and greenhouse gases of vehicle. Exhaust emissions and greenhouse gases of automotive had many problem such as the cause of ambient pollution, health effects. In order to reduce these emissions, many countries are regulating new exhaust gas test modes. Worldwide harmonized light-duty vehicle test procedure (WLTP) for emission certification has been developed in WP.29 forum in UNECE since 2007. This test procedure was applied to domestic light duty diesel vehicles at the same time as Europe. The air pollutant emissions from light-duty vehicles are regulated by the weight per distance, which the driving cycles can affect the results. Exhaust emissions of vehicle varies substantially based on climate conditions, and driving habits. Extreme outside temperatures tend to increasing the emissions, because more fuel must be used to heat or cool the cabin. Also, high driving speeds increases the emissions because of the energy required to overcome increased drag. Compared with gradual vehicle acceleration, rapid vehicle acceleration increases the emissions. Additional devices (air-conditioner and heater) and road inclines also increases the emissions. In this study, three light-duty vehicles were tested with WLTP, NEDC, and FTP-75, which are used to regulate the emissions of light-duty vehicles, and how much emissions can be affected by different driving cycles. The emissions gas have not shown statistically meaningful difference. The maximum emission gas have been found in low speed phase of WLTP which is mainly caused by cooled engine conditions. The amount of emission gas in cooled engine condition is much different as test vehicles. It means different technical solution requires in this aspect to cope with WLTP driving cycle.

• 한국사회정책
• /
• v.23 no.2
• /
• pp.49-81
• /
• 2016

This study agrees with the idea that a situation centered perspective provides a useful contribution in understanding women's attitude on organizations. Women's occupational experiences are less related to their "femaleness" than to the structural constraints inherent in the occupational positions women fill. So characteristics of the organizational situation including gender composition and hierarchical status may "shape and define" women's experience on the job. The present study examined the managerial level's gender gap and "glass ceiling" of the corporation. According to Kanter, if the ratio of women to men in organizations begins to shift, as affirmative action and new hiring and promotion policies promised, forms of relationships and corporate culture should also change. However, the mere presence of women on workplace may not, in itself, result in women-friendly work condition. This study analyzes "Korean Women Manger Panel survey(2010 3rd. wave)" to examine how much gender gap of the managerial level persists and when the glass ceiling effect emerges. Using t-test and ANOVA, various aspects of the gender gap within managerial level were verified. The most significant finding is the glass ceiling effect starts from very low level of management. Policy implications from the statistical analysis of the Panel survey are: 1) We need to increase the absolute number of the women managers for securing middle level women leadership pipe line. 2) We need to confront the fact that the glass ceiling starts from the very low managerial level, and to explore more realistic way to break up the vicious circle for the tokenism. and 3) We need to looking beyond numbers in approaching women's matter at work. At the cultural and institutional level, work-family programs and policies, women's ratings of their competence, and family-friendly organization's climate should be considered.

• Trans-
• /
• v.7
• /
• pp.103-121
• /
• 2019

In some documentary films, there are interviews, but in some other ones, there aren't any. As for the documentaries with interviews, the director uses talking heads to suggest their own arguments and to have audience agree. It is evident that interviews play a key role since they lead the story of a human-related documentary. Some directors prefer interviews where directors' questions and interviewees' answers are both heard. On the other hand, there a re directors who carry out the story just by using the answers from the interviewees. Then, it becomes crucial that we understand both of these styles and have new perspectives when watching documentary films. Ethics has always been considered one of the most important factors in documentaries and since they are believed to be "true," the influence documentaries have on the society is enormous. However, possibilities of exaggerating or manipulating the "truth" always exist. Therefore, it is important for the audience to identify the intentions of the director. As a matter of fact, there have been countless researches being done, but it is difficult to find studies that discuss the ways interviews are used in documentary films. The two different styles mentioned above do have huge differences in terms of directing methods. Thus, taking a look at differences from diverse angles will help us better understand the essentials of documentary films. This study will take examples from the interviews in Michael Moore's (2002), (2007) and observe how the flow of interviews can change when the voice of the director gets involved. There will also be a close examination of interviews in Kim Ilran and Hong Ji Yoo's (2011), and (2005) directed by Jim Butterworth, Aeron Lubarsky, and Lisa Sleeth, as well as Sebastian Junger and Tim Hetherington's (2010). By a careful review, use of dissolve, cross-cutting, and flashback will be analyzed to show how different editing techniques have an impact on subjective views of the director.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.43 no.1
• /
• pp.22-27
• /
• 2023

This experiment was conducted to confirm the possibility of preparing Sorghum×sudangrass hybrid artificial hay using far-infrared rays in Korea. The machine used in this experiment is a drying device based on far-infrared rays, and is designed to control temperature, air flow rate, far-infrared radiation amount, and air flow speed. The Sorghum×sudangrass hybrids harvested in late September were wilted in the field for one day, and a drying test was performed on them. Conditions for drying were performed by selecting a total of 7 conditions, and each condition induced a change in radiation amount in a single condition (42%) and two steps (4 treatments) and three steps (2 treatments). The speed of the air flow in the device was fixed at 60 m/s, and the run time was changed to 30, 60, and 90 minutes. The average dry matter (DM) content was 82.84%. The DM content was 59.94 and 76.91%, respectively, in drying conditions 1 and 3, which were not suitable for hay. In terms of drying rate, it was significantly higher than 80% in the 5, 6 and 7 treatment, and power consumption was slightly high with an average of 5.7 kw/h. As for the feed value according to each drying condition, the crude protein (CP) content increased as the drying time increased, and there was no significant difference between treatments in ADF, NDF, IVDMD and TDN content. In terms of RFV, treatment 1, which is a single condition, was significantly lower than the complex condition. Through the above results, it was determined that the drying conditions 4 and 5 were the most advantageous when considering the drying speed, power consumption, and quality.

• Journal of Animal Science and Technology
• /
• v.52 no.5
• /
• pp.375-382
• /
• 2010

Twelve pigs were used to investigate the effects of polyclonal antibody candidate against abdominal (AAb) and subcutaneous adipocyte membrane proteins (SAb) on body weight, fecaldigestibility and blood metabolites. When AAb and SAb developed by Choi et al. (2010) were injected to pigs, the numerical increase in BW (body weight) occurred at 4 weeks post-treatment, but BW for an entire period was also increased, indicating that the BW increase may not be affected by the antibodies injection. Antibodies treatment did not affect (P>0.05) fecal digestibility of dry matter, crude protein, crude fat and crude fiber. Fecal digestibility of crude ash for control (no treatment) at 2 weeks decreased, and that for non-immunized serum treatmentgroup at 4 weeks post-treatment increased, respectively (P<0.05). However, fecal digestibility of crude ash for AAb and SAb groups did not significantly change. At 4 weeks after the antibodies treatment, blood urea N concentration for AAb and SAb groups was significantly increased (P<0.05). However, these increases may not be caused by the antibodies treatment because similar pattern in blood urea N concentration occurred before the antibodies treatment. Antibodies treatment did not affect concentration of plasma glucose and triglycerides (P<0.05). Compared with control, concentration of plasma total cholesterol for AAb and SAb groups at 4 weeks post-treatment was significantly (P<0.05) decreased. This may suggest that body fat reduction possibly occurs. In conclusion, the AAb and the SAb developed by Choi et al. (2010) may have safety in nutritional physiological metabolism in pigs. Further study on in vivo fat reduction of the antibodies against abdominal and subcutaneous adipocytes of pigs should be required for fat-reduced pork production.

• Journal of Korea Port Economic Association
• /
• v.38 no.1
• /
• pp.101-111
• /
• 2022

As Asia's leading advanced country, Korea has an absolute advantage over foreign trade routes and maritime economies over inland countries. Following the change in social background, the original port area is for various reasons, and some ills are gradually revealing people's private interests. Due to this, it is the economic interest and future development space of the marine industry cluster in the port area that are directly affected and damaged. This study studied the relationship between marine industry clusters and port urban regeneration. It is intended to present the necessity and importance of activating the marine industry cluster through port urban regeneration while analyzing the regenerative design from the quantitative analysis angle. Therefore, first of all, the theoretical backgrounds were considered, and the cases of port cities that did well worldwide were analyzed according to the current status of the northern port of Busan, the research target site, through analysis. In addition, in order to increase the reliability of this study, the data of marine industry clusters and port city regeneration were reviewed using empirical analysis. Looking at the results of this study's case study and empirical analysis, it is a relationship that actually improved and interacted between the marine industry cluster and the port city regeneration. Through the study, it is expected that the Busan North Port Redevelopment Project will be promoted at the design, environmental, and economic level, and at the same time, it will be able to enhance its status as a marine city in Busan. The results show that, no matter which country or port city, the development of economy, society, culture and will inevitably promote the vigorous development of the marine industrial cluster, also, the port area development to a certain degree. will naturally the physical conditions of regional development obstacle through the port city of regeneration. This promotion will overcome.

• Journal of The Korean Association For Science Education
• /
• v.24 no.3
• /
• pp.519-531
• /
• 2004

In recent years, there has been an increased emphasis on performance assessment to evaluate students' abilities. Our nation has introduced a change in testing and assessment. Additional work on the efficacy, reliability, and comparability in order to develop the performance assessment item has been needed in the enforcement of the 7th National Science Curriculum. Also, criteria for professional and technical standards has been needed to be developed. The purpose of this study was to draw out various key concepts and to develop achievement standards, assessment standards and performance assessment items based on the 7th National Science Curriculum on the subject matter of reproduction(chapter 13) and biological accumulation(chapter 17). And also, this study examined the validity of completed performance assessment items based on classical test theory and polytomous item response theory. Twelve key concepts in chapter 13(reproduction) and four from chapter 17(biological accumulation) were abstracted. Twenty-six achievement standards in chapter 13(reproduction), and nine in chapter 17(biological accumulation) were developed. The achievement standards were determined in terms of knowledge(K), process skill(P) and attitude(A). Twenty-five assessment standards in chapter 13(reproduction) and nine in chapter 17(biological accumulation) were developed. Based on the developed achievement standards and assessment standards, twenty-two performance assessment items(seventeen open-ended questions, three essays, and two portfolios) with concrete grading criteria were developed. Eight open-ended items were applied to 240 10th graders to evaluate reliabilities of the test which consisted of four items per each chapter. The results would be suggested that the applied items were valid for performance assessment because item difficulties and item discriminations were proper. There was not much differences in item discrimination between interpretation from classical test theory and that from polytomous item response theory. However, there were some differences in item difficulties between the interpretations of two theories because the characteristics of examinees were reflected in classical test theory.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.39 no.4
• /
• pp.207-215
• /
• 2019

This study was conducted to establish spring sowing techniques in preparation for the impacts of climate change on sowing time and wintering rates of winter forage crops such as barley, oat and IRG. Oat showed the highest yield in 2017 which had relatively dry climate condition. And when sowing in late Febrnary 2017 yielding 9,408kg/ha were obtained, yielding 4,011kg/ha more than IRG's sown in the same period. In 2018 which had relatively wet climate condition, four barley species decreased in the production from the previous year. Oat also had decreased by 70% from 9,408kg/ha to 2,851kg/ha. On the other hand, IRG maintained the production in the mid-5,000kg/ha range. It was also found that IRG had the least variability due to external influences regardless of seeding period for 2 years. Mixed sowing with IRG and oat in 50:50 ratio was the highest dry matter, 6,584kg/ha, and IRG was 18.5% and Oat was 2.3 times higher than single planting.