• Korean Journal of Environment and Ecology
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• v.36 no.2
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• pp.139-149
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• 2022

This study aimed to prepare basic data for protecting the habitat of Fairy Pitta Pitta nympha and coping with climate change by detecting songs with bio-acoustic recording technology and identifying phenological characteristics in protected areas in Korea. The study sites were 36 protected areas nationwide. Data were collected between January and December 2019, and the analysis period was from May 1 to August 31, 2019. The main results are described as follows. Firstly, songs were detected in 22 out of 36 study sites. Frequency analysis results of songs show that high frequency was observed in southern inland, including Jeju island, and the area with the highest latitude was Seoraksan National Park. Secondly, the first song was observed in Hallyeohaesang National Park Geumsan on May 14, 2019, and the last song was observed in Ungok wetland in Gochang on August 6, 2019. Thirdly, circadian rhythm analysis results of songs show that the frequency rapidly increased at five o'clock in the morning, peaked at six o'clock, and then decreased afterward. Fourthly, seasonal cycle analysis results of songs show that they were observed from May 14, 2019 to August 6, and the day with the highest accumulated frequency of songs was June 3, 2019 (Julian date: 154). The average temperature of the day the songs were detected was 17.4℃, the average precipitation was 0.02mm, and the average humidity was 82.6%. Fifthly, a correlation analysis result between Fairy Pitta's songs and meteorological factors shows that temperature indicated a negative correlation with Fairy Pitta's songs (p<0.001), but precipitation (p=0.053) and humidity (p=0.077) did not indicate a statistical significance (df=471). This study is significant in that it confirmed the distribution of Fairy Pitta's songs using bio-acoustic recording technology in protected areas nationwide and identified their ecological characteristics by precisely analyzing the relationship between the song period and meteorological factors.

• Journal of Venture Innovation
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• v.6 no.4
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• pp.41-62
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• 2023

Given that SME workers are the driving force of national competitiveness and the basis and cornerstone of the industry, it is meaningful to study workers' job satisfaction and the factors that affect job satisfaction. In addition to variables related to corporate competitiveness and organizational justice, this study introduced variables such as environmental(E) activities, social(S) activities, and governance(G) activities, which th national government uses as major management evaluation indicators. Therefore, a literature study and empirical analysis were conducted on how self-efficacy affects job satisfaction when workers are faced with a changed work environment. To conduct this study, 300 copies of data were collected from workers in small and medium-sized enterprises and used for analysis. For data analysis, the SPSS statistical program (Ver. 25.0) was used. The study finds, first, that product or service quality and employee competency among corporate competitiveness had a significant positive(+) effect on job satisfaction. Secondly, among ESG management activities, social(S) activities and governance(G) activities were found to have a significant positive(+) effect on job satisfaction. Third, among organizational justice, distribution justice and procedural justice were found to have a positive(+) effect on job satisfaction. Fourth, self-efficacy was found to mediate the effect of product or service quality, employee competency, social(S) and governance(G) activities among ESG management activities, and procedural justice among organizational justice on job satisfaction. The academic value of this study is that it empirically analyzed the factors that ESG management activities affect workers' jobs,. As a result, it was confirmed that workers were satisfied with their jobs by actively showing interest in social(S) activities and governance(G) activities among ESG management activities and participating in corporate management. In addition, workers sensitive to changes in the external environment can become satisfied with their jobs through self-efficacy when SMEs actively enhance corporate competitiveness, execute ESG management activities, and provide a fair organizational culture. Finally, this study suggests that there's a possibility of improving the competitiveness of SMEs through a virtuous cycle created by a change in perception of job conversion and a decrease in turnover.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.1
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• pp.16-22
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• 2024

Along with the high interest in electric vehicles and new renewable energy, there is a growing demand to apply lithium-ion batteries in the construction equipment industry. The capacity of heavy construction equipment that performs various tasks at construction sites is rapidly decreasing. Therefore, it is essential to accurately predict the state of batteries such as SOC (State of Charge) and SOH (State of Health). In this paper, the errors between actual electrochemical measurement data and estimated data were compared using the Dual Extended Kalman Filter (DEKF) algorithm that can estimate SOC and SOH at the same time. The prediction of battery charge state was analyzed by measuring OCV at SOC 5% intervals under 0.2C-rate conditions after the battery cell was fully charged, and the degradation state of the battery was predicted after 50 cycles of aging tests under various C-rate (0.2, 0.3, 0.5, 1.0, 1.5C rate) conditions. It was confirmed that the SOC and SOH estimation errors using DEKF tended to increase as the C-rate increased. It was confirmed that the SOC estimation using DEKF showed less than 6% at 0.2, 0.5, and 1C-rate. In addition, it was confirmed that the SOH estimation results showed good performance within the maximum error of 1.0% and 1.3% at 0.2 and 0.3C-rate, respectively. Also, it was confirmed that the estimation error also increased from 1.5% to 2% as the C-rate increased from 0.5 to 1.5C-rate. However, this result shows that all SOH estimation results using DEKF were excellent within about 2%.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1195-1206
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• 2011

This study was conducted to apply LCA (Life cycle assessment) methodology to lettuce (Lactuca sativa L.) production systems in Namyang-ju as a case study. Five lettuce growing farms with three different farming systems (two farms with organic farming system, one farm with a system without agricultural chemicals and two farms with conventional farming system) were selected at Namyangju city of Gyeonggi-province in Korea. The input data for LCA were collected by interviewing with the farmers. The system boundary was set at a cropping season without heating and cooling system for reducing uncertainties in data collection and calculation. Sensitivity analysis was carried out to find out the effect of type and amount of fertilizer and energy use on GHG (Greenhouse Gas) emission. The results of establishing GTG (Gate-to-Gate) inventory revealed that the quantity of fertilizer and energy input had the largest value in producing 1 kg lettuce, the amount of pesticide input the smallest. The amount of electricity input was the largest in all farms except farm 1 which purchased seedlings from outside. The quantity of direct field emission of $CO_2$, $CH_4$ and $N_2O$ from farm 1 to farm 5 were 6.79E-03 (farm 1), 8.10E-03 (farm 2), 1.82E-02 (farm 3), 7.51E-02 (farm 4) and 1.61E-02 (farm 5) kg $kg^{-1}$ lettuce, respectively. According to the result of LCI analysis focused on GHG, it was observed that $CO_2$ emission was 2.92E-01 (farm 1), 3.76E-01 (farm 2), 4.11E-01 (farm 3), 9.40E-01 (farm 4) and $5.37E-01kg\;CO_2\;kg^{-1}\;lettuce$ (farm 5), respectively. Carbon dioxide contribute to the most GHG emission. Carbon dioxide was mainly emitted in the process of energy production, which occupied 67~91% of $CO_2$ emission from every production process from 5 farms. Due to higher proportion of $CO_2$ emission from production of compound fertilizer in conventional crop system, conventional crop system had lower proportion of $CO_2$ emission from energy production than organic crop system did. With increasing inorganic fertilizer input, the process of lettuce cultivation covered higher proportion in $N_2O$ emission. Therefore, farms 1 and 2 covered 87% of total $N_2O$ emission; and farm 3 covered 64%. The carbon footprints from farm 1 to farm 5 were 3.40E-01 (farm 1), 4.31E-01 (farm 2), 5.32E-01 (farm 3), 1.08E+00 (farm 4) and 6.14E-01 (farm 5) kg $CO_2$-eq. $kg^{-1}$ lettuce, respectively. Results of sensitivity analysis revealed the soybean meal was the most sensitive among 4 types of fertilizer. The value of compound fertilizer was the least sensitive among every fertilizer imput. Electricity showed the largest sensitivity on $CO_2$ emission. However, the value of $N_2O$ variation was almost zero.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.127-134
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• 2012

Microwave remote sensing can help monitor the land surface water cycle, crop growth and soil moisture. A ground-based polarimetric scatterometer has an advantage for continuous crop using multi-polarization and multi-frequencies and various incident angles have been used extensively in a frequency range expanding from L-band to Ka-band. In this study, we analyzed the relationships between L-, C- and X-band signatures and soil moisture content over the whole soybean growth period. Polarimetric backscatter data at L-, C- and X-bands were acquired every 10 minutes. L-band backscattering coefficients were higher than those observed using C- or X-band over the period. Backscattering coefficients for all frequencies and polarizations increased until Day Of Year (DOY) 271 and then decreased until harvesting stage (DOY 294). Time serious of soil moisture content was not a corresponding with backscattering over the whole growth stage, although it increased relatively until early August (R2, DOY 224). We conducted the relationship between the backscattering coefficients of each band and soil moisture content. Backscattering coefficients for all frequencies were not correlated with soil moisture content when considered over the entire stage ($r{\leq}0.50$). However, we found that L-band HH polarization was correlated with soil moisture content (r=0.90) when Leaf Area Index (LAI)<2. Retrieval equations were developed for estimating soil moisture content using L-band HH polarization. Relation between L-HH and soil moisture shows exponential pattern and highly related with soil moisture content ($R^2=0.92$). Results from this study show that backscattering coefficients of radar scatterometer appear effective to estimate soil moisture content.

• Journal of Korean Society of Steel Construction
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• v.27 no.6
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• pp.513-523
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• 2015

In steel moment frames constructed of H-shapes, strong-axis moment connections should be used for maximum structural efficiency if possible. And most of cyclic seismic testing, domestic and international, has been conducted for strong-axis moment connections and cyclic test data for weak-axis connections is quite limited. However, when perpendicular moment frames meet, weak-axis moment connections are also needed at the intersecting locations. Especially, both strong- and weak-axis moment connections have been frequently used in domestic practice. In this study, cyclic seismic performance of RBS (reduced beam section) weak-axis welded moment connections was experimentally investigated. Test specimens, designed according to the procedure proposed by Gilton and Uang (2002), performed well and developed an excellent plastic rotation capacity of 0.03 rad or higher, although a simplified sizing procedure for attaching the beam web to the shear plate in the form of C-shaped fillet weld was used. The test results of this study showed that the sharp corner of C-shaped fillet weld tends to be the origin of crack propagation due to stress concentration there and needs to be trimmed for the better weld shape. Different from strong-axis moment connections, due to the presence of weld access hole, a kind of CJP butt joint is formed between the beam flange and the horizontal continuity plate in weak-axis moment connections. When weld access hole is large, this butt joint can experience cyclic local buckling and subsequent low cycle fatigue fracture as observed in this testing program. Thus the size of web access hole at the butt joint should be minimized if possible. The recommended seismic detailing such as stickout, trimming, and thicker continuity plate for construction tolerance should be followed for design and fabrication of weak-axis welded moment connections.

• Journal of The Korean Association For Science Education
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• v.40 no.5
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• pp.543-563
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• 2020

This study explores how the teaching practices of two teachers changed during scientific modeling classes. It also aims to understand these changes in terms of the teachers' modeling pedagogical content knowledge (PCK) development. The study participants were two elementary school teachers and their fifth-grade students. The teachers taught eight lessons of scientific modeling classes about the human body. The data analysis was conducted for lessons 1-2 and 7-8, which best showed the change in teaching practice. The two teachers' teaching practices were analyzed in terms of feedback frequency, feedback content, and the time allocated for each stage of model generation, evaluation, and modification. Teacher A led the evaluation and modification stages in a teacher-driven way throughout the classes. In terms of feedback, teacher A mainly used answer evaluation feedback in lesson 1-2; however, in lesson 7-8, the feedback content changed to thought-provoking feedback. Meanwhile, teacher B mostly led a teacher-driven model evaluation and modification in lesson 1-2; however, in lesson 7-8, she let her students lead the model evaluation and modification stages and helped them develop models through various feedbacks. The analysis shows that these teaching changes were related to the development of modeling PCK components. Furthermore, the two teachers' modeling PCK differed in teaching orientation, in understanding the modeling stages, and in recognizing the value of modeling, suggesting the importance of these in modeling teaching practice. This study can help improve the understanding of modeling classes by revealing the relationship between teaching practices and modeling PCK.

• Journal of Life Science
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• v.30 no.1
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• pp.45-57
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• 2020

The prenatal period in livestock animals is crucial for meat production because net increase in the number of muscle fibers is finished before birth. However, there is no study on the growth and development mechanism of muscles in Hanwoo during this period. Therefore, to find candidate genes involved in muscle growth and development during this period in Hanwoo, mRNA expression data of longissimus in Hanwoo at 6 and 9 months post-conceptional age (MPA) were analyzed. We independently identified differentially expressed genes (DEGs) using DESeq2 and edgeR which are R software packages, and considered the overlaps of the results as final-DEGs to use in downstream analysis. The DEGs were classified into several modules using WGCNA then the modules' functions were analyzed to identify modules which involved in myogenesis and adipogenesis. Finally, the hub genes which had the highest WGCNA module membership among the top 10% genes of the STRING network maximal clique centrality were identified. 913(6 MPA specific DEGs) and 233(9 MPA specific DEGs) DEGs were figured out, and these were classified into five and two modules, respectively. Two of the identified modules'(one was in 6, and another was in 9 MPA specific modules) functions was found to be related to myogenesis and adipogenesis. One of the hub genes belonging to the 6 MPA specific module was axin1 (AXIN1) which is known as an inhibitor of Wnt signaling pathway, another was succinate-CoA ligase ADP-forming beta subunit (SUCLA2) which is known as a crucial component of citrate cycle.

• Korean Journal of Animal Reproduction
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• v.23 no.2
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• pp.105-111
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• 1999

The effects of exogenous spleen cells on the progesterone and insulin like-growth factor-I (IGF-I) secretions in luteal cells were studied by using in vitro luteal cell culture system in the Hanwoo luteal cells. The corpora lutea(CL) were collected and pooled from the Korean native cattle(Hanwoo) ovaries from a local slaughter house. After enzymatic dissociation, combined large and small luteal cells(LLC and SLC)(1.0$\times$10$^{6}$ cells/$m\ell$) were incubated in D-MEM media containing antibiotics and 10% FCS. Spleen cells (1.0$\times$10$^{6}$ cells/$m\ell$) obtained from castrated adult male Hanwoo were added to luteal cells and co-cultured for 24 h in the absence or presence of luteinizing hormone (LH) (100 ng). Progesterone contents from luteal tissues were increased at CL-3 stage during each stage of estrous cycle. Progesterone secretion from luteal cell culture by the presence of LH (100 ng/$m\ell$) was positively stimulated compared with control. However, progesterone secretion was not changed by the addition of 5, 10 and 20% of spleen cells in the absence of LH. Co-culture of luteal cells with 10% of spleen cells in the presence of LH(l00ng/$m\ell$) significantly. enhanced after 24 h of culture. IGF-Isecretion from in vitro luteal cells co-culture by the addition of spleen cells (5%, 10% and 20%) was not significantly effected. Besides, in the presence of LH (100ng/$m\ell$), IGF-Isecretions from luteal cells by addition of spleen cells were higher than control media. However, LH alone significantly increased IGF-I secretion at 24 h of culture. These data provide the demonstrate that spleen cells can enhance LH action so as to stimulate progesterone secretion from Hanwoo luteal cells but have no effect to stimulate IGF-I secretion.

• Journal of Life Science
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• v.26 no.3
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• pp.376-386
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• 2016

Apoptosis induction has been proposed as an efficient mechanism by which malignant tumor cells can be removed following chemotherapy. The intrinsic mitochondria-dependent apoptotic pathway is frequently implicated in chemotherapy-induced tumor cell apoptosis. Since DNA-damaging agent (DDA)-induced apoptosis is mainly regulated by the tumor suppressor protein p53, and since more than half of clinical cancers possess inactive p53 mutants, microtubule-damaging agents (MDAs), of which apoptotic effect is mainly exerted via p53-independent routes, can be promising choice for cancer chemotherapy. Recently, we found that the apoptotic signaling pathway induced by MDAs (nocodazole, 17α-estradiol, or 2-methoxyestradiol) commonly proceeded through mitotic spindle defect-mediated prometaphase arrest, prolonged Cdk1 activation, and subsequent phosphorylation of Bcl-2, Mcl-1, and Bim in human acute leukemia Jurkat T cells. These microtubule damage-mediated alterations could render the cellular context susceptible to the onset of mitochondria-dependent apoptosis by triggering Bak activation, Δψm loss, and resultant caspase cascade activation. In contrast, when the MDA-induced Bak activation was inhibited by overexpression of anti-apoptotic Bcl-2 family proteins (Bcl-2 or Bcl-xL), the cells in prometaphase arrest failed to induce apoptosis, and instead underwent mitotic slippage and endoreduplication cycle, leading to formation of populations with 8N and 16N DNA content. These data indicate that cellular apoptogenic mechanism is critical for preventing polyploid formation following MDA treatment. Since the formation of polyploid cells, which are genetically unstable, may cause acquisition of therapy resistance and disease relapse, there is a growing interest in developing new combination chemotherapies to prevent polyploidization in tumors after MDA treatment.