• Journal of Korea Water Resources Association
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• v.55 no.5
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• pp.371-381
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• 2022

Since tributaries have greater water quality variability than main streams, a comprehensive evaluation method that considers the effects of various parameters rather than one water quality parameter has been introduced for effective water quality management of tributaries, but the characteristic of the watershed is not considered. In this study, the urbanization rate, livestock excreta generation, and industrial wastewater discharge in the Hantan River middle-watershed classify urban and non-urban watersheds, and evaluate the suitability of water quality indexes by watershed characteristics by analyzing water quality characteristics and calculating CCME WQI, RTWQI, and NSFWQI. Factor analysis was used to understand the effect of water quality parameters used to calculate the water quality index on the water quality index results. As a result of the factor analysis, the relationship between CCME WQI, TC, and FC was derived, and the relationship between RTWQI and DO, SS in urban watersheds and NSFWQI and FC in non-urban watersheds was revealed. As a result of evaluating suitability through comparison with BOD and T-P grades, it was interpreted that the suitability of the water quality index was low in urban watersheds and that comprehensive water quality evaluation using RTWQI was possible in non-urban watersheds.

• Resources Recycling
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• v.31 no.1
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• pp.56-64
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• 2022

Construction waste is generated at a rate of approximately 221,102 tons/day in Korea. In particular, mixed construction waste generates approximately 24,582 tons/day. The other components were recycled by 98.9%. The amount of greenhouse gas emissions from the waste was 17.1 million tons of CO2 equaling 2.3% of the total greenhouse gas emissions. To reduce greenhouse gas emissions, reducing the environmental impact is becoming increasingly important. However, appropriate treatment must first be established, as mixed construction waste is also increasing. Thus, an effective plan is urgently needed because it is frequently segregated and sorted by the landfill and incinerated. In addition, there is an urgent need to prepare various effective recycling methods rather than a simple treatment. Therefore, this study analyzed the environmental impact of the treatment of mixed construction waste by calculating greenhouse gas emissions. As a result, the highest greenhouse gas generation occurred during the incineration stage. Moreover, the optimal method to reduce greenhouse gas emissions is recycling and energy recovery from waste. In addition, the amount of greenhouse gas generated during energy recovery from the waste stage was the second highest. However, greenhouse gas emissions can be reduced by using waste as energy to reduce fossil fuel consumption. In addition, for the transportation stage, the optimal reduction plan is to minimize the amount of greenhouse gas emissions by setting the optimal distance and applying biofuel and electric vehicle operations.

• The Journal of the Korea Contents Association
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• v.22 no.9
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• pp.531-543
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• 2022

This study aims to examine the mediating effects of ethical leadership and the moderating effects of organizational culture in relation to the impact of public service motivation on innovative behavior by public officials. This research utilizes data from the 2021 Public Employee Perception Survey conducted to public officials by the Korea Institute of Public Administration. Public service motivation had a positive effect on innovative behavior and ethical leadership, while ethical leadership had a positive effect on innovative behavior. In addition, ethical leadership mediated the relationship between public service motivation and innovative behavior. Under organizational culture, hierarchical and innovative cultures exhibited moderating effects. The policy and practical implications of these findings are as follows. First, it is important to build ethical leadership in order to retain the national competitiveness of public officials and encourage innovative behaviors that can adapt to changes at public organizations. Second, the competition rate for public service examinations has fallen recently. This may be interpreted as an unfavorable perception of public service bureaucracy among the MZ generation. Consequently, in line with the changing times, the organizations of public officials must adopt to a future-oriented, innovative culture. Third, it is necessary to explore alternative methods for developing an innovative culture, such as giving greater flexibility and autonomy through transfer of authority to public officials who address the public directly.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.4
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• pp.378-383
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• 1989

For selection of mutants two rice varieties, Sangpungbyeo and Seomjinbyeo, were irradiated with 20 kR and 25 kR of gamma rays. One panicle per each plant was harvested in Ml, and single needling per hill was planted for M2 and M3 generations. Mutations for short culm, earliness and the major traits were examined. 1. The mutation rates were varied with the rice varieties and the doses of radiation, higher in Sangpungbyeo and 25kR than in Seomjinbyeo and 20 kR, respectively. 2. The rates in Sangpungbyeo with the 20 kR and 25 kR were 1.10％ and 1.47％. respectively and those of Seomjinbyeo were 0.51％ and 1.25％, respectively. 3. The culm lengths of short-culm mutants derived from Sangpungbyeo and Seomjinbyeo were reduced about 10％ compared to their mother varieties, especially it was possible to select the dwarf mutants reducing 57％ and 40％ of culm length in Sangpungbyeo and Seomjinbyeo, respectively with the dose of 25 kR irradiation. 4. The range of heading date of the mutant ion in the M3 generation was comparatively wide. Many earliness mutants shortened about 7 days were selected as compared with their mother varieties, some mutants of the irradiated group had early matured by 20 days and 30 days, respectively in both Seomjinbyeo and Sangpungbyeo.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.56-56
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• 2001

The exogenous gene transfer by intracytoplasmic sperm injection (ICSI) procedure has been recently used to produce transgenic mice and pigs. Sperm-mediated DNA transfer has the potential to markedly simplify the generation of transgenic animals. This method may serve as an alternative to the pronucleus injection of DNA for the production of transgenic pigs. Therefore, in this study, we investigated the expression of transgene after co-injection of spermatozoon or sperm head with green fluorescent protein (GFP) gene into in vitro matured porcine oocytes. Spermatozoon and sperm head, that was obtained by sonication, were treated with 0.03% Triton X-100 to remove the membrane. They were preincubated with linearized pEGFP-N1 for 1 min, and then embryos cultured NCSU23 medium for 2.5 days after co-injected of sperm and DNA. We monitored expression of GFP in embryos under epifluorescent microscope. The remove of sperm membrane did not alter the developmental competence of embryos after ICSI. At 7 days following injection, the rates of blastocysts following injection of intact sperm (15.0%), and of sperm with disrupted membrane (14.2%) were higher than that following IVF (10.0%). Porcine oocytes injected with sperm which co-cultured with DNA concentration of 1, 0.1, and 0.01 ng were 60, 65.7 and 75% and 18.5, 37.4 and 22.2% for rates of cleavage and GFP expression, respectively. In vitro matured porcine oocytes injected with sperm and isolated sperm head resulted in 69 and 59.7% of cleavage rates, respectively The rates of embryo GFP expressed did not significantly different between sperm (20.4%) and sperm head (20.0%) injection. The transgenic embryos with the clusters of positive blastomeres were observed under fluorescent microscope. Most of embryos expressed GFP gene showed mosaicism. They showed GFP expression at 1/4, 2/4 and 3/4 of blastomeres at the 4-cell stage. Among these 4-cell embryos, the expression rate of 1/4 blastomere group (54.6%) was higher than the other groups (15.3-30.7%). These results indicate that membrane disrupted sperm could attach with exogenous DNA, and that this procedure may be useful to introduce foreign gene into porcine oocytes. Therefore, our data suggest that the ICSI car be a useful tool to efficiently produce transgenic pig as well as other mammals.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.7
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• pp.1201-1208
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• 2022

In general, to maximize the supply and efficiency of floating offshore wind power generation energy, the motion caused by wave attenuation of the substructure must be reduced. According to previous studies, the motion response was reduced due to the vortex viscosity generated by the damping plate installed in the lower structure among the waves. In this study, a 5 MW semi-submersible OC5 platform and two platforms with attenuation plates were designed, and free decay experiments and numerical calculations were performed to confirm the effect of reducing motion due to vortex viscosity. As a result of the model test, when the heave free decay tests were conducted at drop heights of 30 mm, 40 mm, and 50 mm, compared with the OC5 platform, the platform with two types of damping plates attached had relatively improved motion damping performance. In the model test and numerical calculation results, the damping plate models, KSNU Plate 1 and KSNU Plate 2, were 1.1 times and 1.3 times lower than OC5, respectively, and the KSNU Plate 2 platform showed about two times better damping performance than OC5. This study shows that the area of the damping plate and the vortex viscosity are closely related to the damping rate of the heave motion.

• Journal of the Korean Society for information Management
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• v.40 no.3
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• pp.245-271
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• 2023

The purpose of this study was to assess the perception of e-book subscription services among the digitally native generation in their twenties, who have a high e-book usage rate. This study employed a mixed-methods approach, combining survey responses and usability testing. It aimed to assess the awareness and usage of e-book subscription services among university students in their twenties, a demographic known for their high utilization of electronic devices and e-books. The survey was conducted among 202 university students, and the responses were categorized and examined based on whether they were users or non-users. As a result of the survey, I found there is different awareness of e-book between users and non-users, on the other hand, convenience and portability are the strong point of e-books for users and non-users commonly also. Usability testing was performed on a group of 10 university students in their twenties who had not previously used the 'Millies Library' application, which is renowned as the most widely-used e-book platform. Following the experiment, participants expressed positive feedback regarding various optional features, convenience, design, and cost-effectiveness. However, they also had negative reactions concerning touch errors, malfunctions, functional practicality, a lack of interest, system issues, and the absence of a library.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.4
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• pp.173-179
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• 2023

This paper analyzes the time-dependent dielectric breakdown(TDDB) degradation mechanism for each stress region of Peri devices manufactured by 4th generation VNAND process, and presents a complementary lifetime prediction model that improves speed and accuracy in a wider reliability evaluation region compared to the conventional model presented. SiON dielectric nMOSFETs were measured 10 times each under 5 constant voltage stress(CVS) conditions. The analysis of stress-induced leakage current(SILC) confirmed the significance of the field-based degradation mechanism in the low electric field region and the current-based degradation mechanism in the high field region. Time-to-failure(TF) was extracted from Weibull distribution to ascertain the lifetime prediction limitations of the conventional E-model and 1/E-model, and a parallel complementary model including both electric field and current based degradation mechanisms was proposed by extracting and combining the thermal bond breakage rate constant(k) of each model. Finally, when predicting the lifetime of the measured TDDB data, the proposed complementary model predicts lifetime faster and more accurately, even in the wider electric field region, compared to the conventional E-model and 1/E-model.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.4
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• pp.70-77
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• 2023

Fine dust is a cause of serious ecological problems, and fugitive dust generated from construction sites is a major source of fine dust in Korea. However, at construction sites, including concrete manufacturing industry sites, measurements are rarely made at the fugitive dust generation stage, and passive removal methods are the majority. Therefore, in this study, a fugitive dust measurement method suitable for managing fugitive dust generated during aggregate unloading in the concrete manufacturing industry sites was selected. In addition, the purpose was to analyze the amount of fugitive dust reduction according to the operation of the reduction system by applying the automatic fugitive dust reduction system to the aggregate unloading site. As a result, the reliability of the light scattering method was secured through the comparative measurement of the beta-ray absorption method and the light scattering method, and the light scattering method correction coefficient was calculated and applied to the measured value of the fugitive dust particle mass concentration at the concrete manufacturing industry sites. In addition, the fugitive dust reduction rate according to the operation of the automatic fugitive dust reduction system was derived.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.1
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• pp.55-61
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• 2023

This study aims to develop CLSM fill material for emergency restoration using landfill coal ash. As a result of examining physical properties such as particle size distribution and fines content of landfill coal ash, bottom ash, fly ash, and general soil were mixed, and SP was found to have a density of 2.03 and a residual particle pass rate of 7.8 %. CLSM materials that secure fluidity in unit quantities without using chemical admixtures such as glidants and water reducing agents have a high risk of material separation due to bleeding. As a result of this experiment, it was found that the bleeding ratio did not satisfy the standard in the case of the specimen with a large amount of fly ash and a lot of addition of mixing water. As a result of the compressive strength test, the strength development of 0.5 MPa or more for 4 hours was found to be satisfactory for the specimens using hemihydrate gypsum with a unit binder amount of 200 or more, and the remaining gypsum showed poor strength development. Although it is judged that landfill coal ash can be used as a CLSM material, it is necessary to identify and apply the physical and chemical characteristics of coal ash buried in the ash treatment plant of each power generation company.