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Study on Spatial Change of Urban Forest Considering Definition of Urban Area in South Korea (도시지역 정의에 따른 도시숲의 공간적 변화에 관한 연구)

  • Doo-Ahn, KWAK;So-Hee, PARK
    • Journal of the Korean Association of Geographic Information Studies
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    • v.25 no.4
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    • pp.19-31
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    • 2022
  • The definition of urban forest is described as all forest and trees except the Natural Parks throughout whole territory in Urban Forest Act. But the concept of urban forest in the law differs from general awareness by Korean citizen and from definitions of other countries. For discussing such differences of urban forest definition, it was tested how much urban forest area would be changed according to the various definition of urban area. The urban area was defined to be four scenarios in this study in consideration of "urban area" by National Land Planning and Utilization Act (NLPUA), 300m buffered boundary from the "urban area" proposed by World Health Organization (WHO) and forest watershed area. In the scenario 1, including forest watershed intersected with "urban area" by NLPUA, urban forest area was estimated at 1.83 million ha in which urban forest area per person was 386㎡. In the scenario 2, including forest watershed intersected with 300m buffered boundary from the "urban area" by NLPUA, urban forest area was estimated at 1.92 million ha in which urban forest area per person was 405㎡. In the scenario 3, including forest watershed intersected with "urban area" placed within administration boundary (Eup·Dong districts), urban forest area was estimated at 1.08 million ha in which urban forest area per person was 230㎡. In the scenario 4, including forest watershed intersected with 300m buffered boundary from "urban area" placed within administration boundary, urban forest area was estimated at 1.20 million ha in which urban forest area per person was 256㎡. Therefore, the boundary of urban area should be agreed clearly prior to defining the urban forest area for avoiding unclear area calculated according to different definitions.

Development and Feasibility Study of the Nature of Science Instrument for Elementary School Students (초등학생용 과학의 본성 검사 도구 개발 및 타당성 검토)

  • Park, Jaehyeon;Park, Jaeyong
    • Journal of Korean Elementary Science Education
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    • v.41 no.4
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    • pp.701-724
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    • 2022
  • In this study, the Nature of Science (NOS) instrument for elementary school students in the form of open questionnaires was developed specifically to reveal elementary school students' perceptions of the NOS, and its validity and effectiveness were investigated. To develop a NOS instrument for elementary school students, problems that may occur when applying the existing NOS instruments to elementary school students were analyzed and based on this, the development direction of the NOS instrument was established. In addition, after selecting seven NOS types suitable for the level of elementary school students, the preliminary instrument was produced by modifying and supplementing the items in the existing instruments for each type or by developing new items. Finally, the NOS instrument consisting of eight questions was developed by adding one question asking for a comprehensive understanding of science to seven questions related to each type of NOS after a content validity test of the science education expert group. To verify the practical effect of the developed instrument, pre- and post-tests were conducted on 50 students in two classes of sixth grade at two elementary schools in Seoul: 'existing instrument → development instrument' in one class, and 'development instrument → existing instrument' in the other class. The collected data were then compared and evaluated through summary content analysis and analyzed by executing the Wilcoxon signed-rank test. As a result of comparing and analyzing students' responses to the existing NOS instrument and the developed NOS instrument, students' perspectives on the NOS were more diverse when using the developed instrument, and the level of error in the response caused by misinterpreting the intention of the question was reduced. In addition, when using the developed instrument, the responses of the majority of students at a statistically significant level changed more specifically. In this study, the implications for the development of NOS instruments suitable for elementary school students were discussed based on these results.

pH, Ion Release Capability, and Solubility Value of Premixed Mineral Trioxide Aggregates (Premixed MTA제재의 pH, 이온 유리 정도, 용해도)

  • Seolah, Back;YuJi, Jang;Junghwan, Lee;Joonhaeng, Lee;Jisun, Shin;Jongbin, Kim;Miran, Han;JongSoo, Kim
    • Journal of the korean academy of Pediatric Dentistry
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    • v.49 no.4
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    • pp.379-391
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    • 2022
  • The current study aimed to compare the pH, solubility value, and ion release capability of premixed mineral trioxide aggregates (MTAs) versus conventional pulp capping materials before and after setting. The following materials were used: resin-modified calcium silicate cement (TheraCal LC®, TLC), resin-modified calcium hydroxide cement (Ultra-BlendTM plus, UBP), and 2 kinds of premixed MTA (Endocem MTA® premixed regular [EMPR] and Well-RootTM PT [WRP]). The specimens of each material were prepared before and after setting and were immersed in distilled water. The materials' pH and solubility value were assessed. Next, three kinds of ion (calcium, sulfide, and strontium) released by pulp capping materials were evaluated via inductively coupled plasma atomic emission spectrometry. In the after-setting group, the pH of TLC and UBP decreased. However, the pH of the premixed MTAs increased with time. TLC released a higher concentration of strontium ion compared with the other materials. Meanwhile, EMPR released a significantly high concentration of sulfide ion (p < 0.05). In the after-setting group, the 2 kinds of premixed MTAs released a significantly higher concentration of calcium ion compared with the other materials (p < 0.05). In the after-setting group, EMPR had a significantly low solubility value (p < 0.05). The Kruskal-Wallis test, followed by the Mann-Whitney U test with Bonferroni correction, was used in statistical analysis. In conclusion, resin-modified calcium silicate cement, modified calcium hydroxide cement, and the 2 kinds of premixed MTAs had an alkaline pH and low solubility value and they released various concentrations of ions after setting.

Optimization for Removal of Nitrogen Using Non-consumable Anode Electrodes (비소모성 Anode(산화전극)을 이용한 질소 제거 최적화)

  • Hyunsang, Kim;Younghee, Kim
    • Clean Technology
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    • v.28 no.4
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    • pp.309-315
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    • 2022
  • Research was conducted to derive the optimal operation conditions and the optimal cathode for using a DSA electrode as an anode to minimize electrode consumption during the removal of nitrogen from wastewater by the electro-chemical method. Of the various electrodes tested as cathodes, brass was determined to be the optimal electrode. It had the highest NO3-N removal rate and the lowest concentration of residual NH3-N, a by-product when Cl is present in the solution. Investigating the effect of current density found that when the initial concentration of NO3-N was 50 mg L-1, the optimal current density was 15 mA cm-2. In addition, current densities above 15 mA cm-2 did not significantly affect the NO3-N removal rate. The effect of electrolytes on removing NO3-N and minimizing NH3-N was investigated by using Na2SO4 and NaCl as electrolytes and varying the reaction times. When Na2SO4 and NaCl are mixed at a ratio of 1.0 g L-1 to 0.5 g L-1 and reacted for 90 min at a current density of 15 mA cm-2 and an initial NO3-N concentration of 50 mg L-1, the removal rate of NO3-N was about 48% and there was no residual NH3-N. On the other hand, when using only 1.5 g L-1 of NaCl as an electrolyte, the removal rate of NO3-N was the highest at about 55% and there was no residual NH3-N.

On Vortex Reduction Characteristics of Pump Sump Circulating Water Intake Basin of Power Plant Using Hydraulic Experiment (수리실험을 이용한 발전소의 순환수 취수부 흡입수조의 와류저감에 관한 연구)

  • Eom, Junghyun;Lee, Du Han;Kim, Hung Soo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.42 no.6
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    • pp.815-824
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    • 2022
  • Among the main facilities of the power plant, the circulating water used for cooling the power generation system is supplied through the Circulation Water Intake Basin (CWIB). The vortexes of various types generated in the Pump Sump (PS) of CWIB adversely affect the Circulation Water Pump (CWP) and pipelines. In particular, the free surface vortex accompanied by air intake brings about vibration, noise, cavitation etc. and these are the causes of degradation of CWP performance, damage to pipelines. Then power generation is interrupted by the causes. Therefore, it is necessary to investigate the hydraulic characteristics of CWIB through the hydraulic model experiment and apply an appropriate Anti Vortex Device (AVD) that can control the vortex to enable smooth operation of the power plant. In general, free surface vortex is controlled by Curtain Wall (CW) and the submerged vortex is by the anti vortex device of the curtain wall. The detailed specifications are described in the American National Standard for Pump Intake Design. In this study, the circulating water intake part of the Tripoli West 4×350 MW power plant in Libya was targeted, the actual operating conditions were applied, and the vortex reduction effect of the anti vortex device generated in the suction tank among the circulating water intake part was analyzed through a hydraulic model experiment. In addition, a floor splitter was basically applied to control the submerged vortex, and a new type of column curtain wall was additionally applied to control the vortex generated on the free surface to confirm the effect. As a result of analyzing the hydraulic characteristics by additionally applying the newly developed Column Curtain Wall (CCW) to the existing curtain wall, we have found that the vortex was controlled by forming a uniform flow. In addition, the vortex angle generated in the circulating water pump pipeline was 5° or less, which is the design standard of ANSI/HI 9.8, confirming the stability of the flow.

Productivity and Cost of Mechanized Felling and Processing Operations Performed with an Excavator-based Stroke Harvester by Tree Species (수종에 따른 스트로크 하베스터의 벌도⋅조재작업 생산성 및 비용)

  • Yun-Sung, Choi;Min-Jae, Cho;Ho-Seong, Mun;Jae-Heun, Oh
    • Journal of Korean Society of Forest Science
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    • v.111 no.4
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    • pp.567-582
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    • 2022
  • Chainsaw use for motor-manual timber harvesting in South Korea is associated with worker safety issues. However, forestry operations such as timber harvesting have already been mechanized to reduce hazards to workers and increase productivity. This study analyzed the productivities and costs of felling and processing, felling and processing using an excavator-based stroke harvester for Pinus rigida and Quercus mongolica stands. To efficiently operate the stroke harvester, we developed a regression equation to estimate the productivities of felling and processing, felling, and processing operations,and we conducted sensitivity analysis of the operation costs using DBH and machine utilization. The felling and processing productivity was 6.53 and 4.02 m3/SMH for P. rigida a nd Q. mongolica, respectively, and the cost was 17,983 and 29,210 won/m3, respectively. The felling productivity for P. rigida a nd Q. mongolica wa s 40.9 and 23.0 m3/SMH, respectively, and the cost was 2,667 and 4,743 won/m3, respectively. The processing productivity for P. rigida and Q. mongolica was 8.25 and 7.75 m3/SMH, respectively, and the cost was 15,296 and 16,283 won/m3, respectively. In the developed regression equation, the DBH, traveling distance, and number of cuttings were found to be important factors (p<0.05). Therefore, it is necessary to construct a DB considering the various conditions and species associated with harvester operations, and further research is needed to increase the accuracy of predicting operation productivity and costs.

Raman Spectroscopic Study for Investigating the Spatial Distribution and Structural Characteristics of Mn-bearing Minerals in Non-spherical Ferromanganese Nodule from the Shallow Arctic Ocean (북극해 천해저 비구형 망가니즈단괴 내 광물종 분포 및 구조적 특성 규명을 위한 라만 분광분석 연구)

  • Sangmi, Lee;Hyo-Jin, Koo;Hyen-Goo, Cho; Hyo-Im, Kim
    • Korean Journal of Mineralogy and Petrology
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    • v.35 no.4
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    • pp.409-421
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    • 2022
  • Achieving a highly resolved spatial distribution of Mn-bearing minerals and elements in the natural ferromanganese nodules can provide detailed knowledge of the temporal variations of geochemical conditions affecting the formation processes of nodules. While a recent study utilizing Raman spectroscopy has reported the changes in the manganate mineral phases with growth for spherical nodules from the Arctic Sea, the distributions of minerals and elements in the nodules from the shallow Arctic Sea with non-spherical forms have not yet fully elucidated. Here, we reported the micro-laser Raman spectra with varying data acquisition points along three different profiles from the center to the outermost rim of the non-spherical ferromanganese nodules collected from the East Siberian Sea (~73 m). The elemental distributions in the nodule (such as Mn, Fe, etc.) were also investigated by energy dispersive X-ray spectroscopy (EDS) analysis to observe the internal structure and mineralogical details. Based on the microscopic observation, the internal structures of a non-spherical nodule can be divided into three different regions, which are sediment-rich core, iron-rich substrate, and Mn-Fe layers. The Raman results show that the Mn-bearing mineral phases vary with the data acquisition points in the Mn-Fe layer, suggesting the changes in the geochemical conditions during nodule formation. In addition, we also observe that the mineral composition and structural characteristics depend on the profile direction from the core to the rim. Particularly, the Raman spectra obtained along one profile show the lack of Fe-(oxy)hydroxides and the noticeably high crystallinity of Mn-bearing minerals such as birnessite and todorokite. On the other hand, the spectra obtained along the other two profiles present the presence of significant amount of amorphous or poorly-ordered Fe-bearing minerals and the low crystallinity of Mn-bearing minerals. These results suggest that the diagenetic conditions varied with the different growth directions. We also observed the presence of halite in several layers in the nodule, which can be evidence of the alteration of seawater after nodule formation. The current results can provide the opportunity to obtain detailed knowledge of the formation process and geochemical environments recorded in the natural non-spherical ferromanganese nodule.

Awareness of the Prevention of Work-Related Diseases among Farmers - Based on Qualitative Research Methods (농업인들의 업무상질환 예방에 대한 인식도 - 질적연구방법을 토대로)

  • Ae-Rim, Seo;Ji-Youn, Kim;Bokyoung, Kim;Gyeong-Ye, Lee;Ki-Soo, Park
    • Journal of agricultural medicine and community health
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    • v.47 no.4
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    • pp.211-219
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    • 2022
  • Objective: This study was conducted to investigate the awareness of work-related disease prevention of farmers. Method: As a research method, a qualitative focus group interview was conducted in 18 participants. Results: Prevention and management services for work-related diseases of farmers mostly are based on research from other fields and so are not highly effective because their content is not relevant to agricultural work. It has been suggested that such program designers be required to have some appropriate related knowledge, and that incentives and a certification system for participation in such education be established. To analyze work-related diseases of farmers, fields of prevention, diagnosis, treatment, and rehabilitation should be created. They demanded the designation of hospitals and the actualization of compensation for farmers' safety insurance. The work-related diseases to address were include musculoskeletal diseases, pesticide poisoning-related diseases (cardiovascular disease, respiratory disease), psychiatric diseases such as depression, and allergic diseases. However, this must have been the result of the harmful factors they felt during agricultural work. And for farmer patients diagnosed with work-related diseases, it was said to strengthen farmer safety insurance. Conclusion: In order to increase the safely and health effects of agricultural work, it is necessary to prevent and manage work-related diseases of farmers. Projects should be developed in consideration of cultural and economic barriers of farmers and the characteristics of the work.

Analysis of Social Trends for Electric Scooters Using Dynamic Topic Modeling and Sentiment Analysis (동적 토픽 모델링과 감성 분석을 활용한 전동킥보드에 대한 사회적 동향 분석)

  • Kyoungok, Kim;Yerang, Shin
    • KIPS Transactions on Software and Data Engineering
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    • v.12 no.1
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    • pp.19-30
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    • 2023
  • An electric scooter(e-scooter), one popularized micro-mobility vehicle has shown rapidly increasing use in many cities. In South Korea, the use of e-scooters has greatly increased, as some companies have launched e-scooter sharing services in a few large cities, starting with Seoul in 2018. However, the use of e-scooters is still controversial because of issues such as parking and safety. Since the perception toward the means of transportation affects the mode choice, it is necessary to track the trends for electric scooters to make the use of e-scooters more active. Hence, this study aimed to analyze the trends related to e-scooters. For this purpose, we analyzed news articles related to e-scooters published from 2014 to 2020 using dynamic topic modeling to extract issues and sentiment analysis to investigate how the degree of positive and negative opinions in news articles had changed. As a result of topic modeling, it was possible to extract three different topics related to micro-mobility technologies, shared e-scooter services, and regulations for micro-mobility, and the proportion of the topic for regulations for micro-mobility increased as shared e-scooter services increased in recent years. In addition, the top positive words included quick, enjoyable, and easy, whereas the top negative words included threat, complaint, and ilegal, which implies that people satisfied with the convenience of e-scooter or e-scooter sharing services, but safety and parking issues should be addressed for micro-mobility services to become more active. In conclusion, this study was able to understand how issues and social trends related to e-scooters have changed, and to determine the issues that need to be addressed. Moreover, it is expected that the research framework using dynamic topic modeling and sentiment analysis will be helpful in determining social trends on various areas.

CLK3 is a Novel Negative Regulator of NF-κB Signaling (NF-κB 신호경로에서 CLK3의 새로운 음성 조절자로서의 기능)

  • Byeol-Eun, Jeon;Chan-Seong, Kwon;Ji-Eun, Lee;Ye-Lin, Woo;Sang-Woo, Kim
    • Journal of Life Science
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    • v.32 no.11
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    • pp.833-840
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    • 2022
  • Chronic inflammation has been shown to be closely associated with tumor development and progression. Nuclear factor kappa B (NF-κB) is composed of a family of five transcription factors. NF-κB signaling plays a crucial role in the inflammatory response and is often found to be dysregulated in various types of cancer, making it an attractive target in cancer therapeutics. In this study, CDC-like kinase 3 (CLK3) was identified as a novel kinase that regulates the NF-κB signaling pathway. Our data demonstrate that CLK3 inhibits the canonical and non-canonical NF-κB pathways. Luciferase assays following the transient or stable expression of CLK3 indicated that this kinase inhibited NF-κB activation mediated by Tumor necrosis factor-alpha (TNFα) and Phorbol 12-myristate 13-acetate (PMA), which are known to activate NF-κB signaling via the canonical pathway. Consistent with data on the ectopic expression of CLK3, CLK3 knockdown using shRNA constructs increased NF-κB activity 1.5-fold upon stimulation with TNFα in HEK293 cells compared with the control cells. Additionally, overexpression of CLK3 suppressed the activation of this signaling pathway induced by NF-κB-inducing kinase (NIK) or CD40, which are well-established activators of the non-canonical pathway. To further examine the negative impact of CLK3 on NF-κB signaling, we performed Western blotting following the TNFα treatment to directly identify the molecular components of the NF-κB pathway that are affected by this kinase. Our results revealed that CLK3 mitigated the phosphorylation/activation of transforming growth factor-α-activated kinase 1 (TAK1), inhibitor of NF-κB kinase alpha/beta (IKKα/α), NF-κB p65 (RelA), NF-κB inhibitor alpha (IκBα), and Extracellular signal-regulated kinase 1/2-Mitogen-activated protein kinase (ERK1/2-MAPK), suggesting that CLK3 inhibits both the NF-κB and MAPK signaling activated by TNFα exposure. Further studies are required to elucidate the mechanism by which CLK3 inhibits the canonical and non-canonical NF-κB pathways. Collectively, these findings reveal CLK3 as a novel negative regulator of NF-κB signaling.