• Title/Summary/Keyword: Gwanak

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Regional Analysis of Extreme Values by Particulate Matter(PM2.5) Concentration in Seoul, Korea (서울시 초미세먼지(PM2.5) 지역별 극단치 분석)

  • Oh, Jang Wook;Lim, Tae Jin
    • Journal of Korean Society for Quality Management
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    • v.47 no.1
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    • pp.47-57
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    • 2019
  • Purpose: This paper aims to investigate the concentration of fine particulate matter (PM2.5) in the Seoul area by predicting unhealthy days due to PM2.5 and comparing the regional differences. Methods: The extreme value theory is adopted to model and compare the PM2.5 concentration in each region, and each best model is selected through the goodness of fitness test. The maximum likelihood estimation technique is applied to estimate the parameters of each distribution, and the fitness of each model is measured by the mean absolute deviation. The selected model is used to estimate the number of unhealthy days (above $75{\mu}g/m^3$ PM2.5 concentrations) in each region, with which the actual number of unhealthy days are compared. In addition, the level of PM2.5 concentration in each region is analyzed by calculating the return levels for periods of 6 months, 1 year, 3 years, and 5 years. Results: The Mapo (MP) area revealed the most unhealthy days, followed by Gwanak (GW) and Yangcheon (YC). On the contrary, the number of unhealthy days was low in Seodaemun (SDM), Songpa (SP) and Gangbuk (GB) areas. The return level of PM2.5 was high in Gangnam (GN), Dongjak (DJ) and YC. It will be necessary to prepare for PM2.5 than other regions. On the contrary, Gangbuk (GB), Nowon (NW) and Seodaemun (SDM) showed relatively low return levels for PM2.5. However, in most of the regions of Seoul, PM25 is generated at a very poor level ($75{\mu}g/m^3$) every 6months period, and more than $100{\mu}g/m^3$ PM2.5 occur every 3 years period. Most areas in Seoul require more systematic management of PM2.5. Conclusion: In this paper, accurate prediction and analysis of high concentration of PM2.5 were attempted. The results of this research could provide the basis for the Seoul Metropolitan Government to establish policies for reducing PM2.5 and measuring its effects.

Polarimetry of solar system small bodies using the Seoul National University 61cm telescope and TRIPOL

  • Jin, Sunho;Ishiguro, Masateru;Kwon, Yuna Grace;Geem, Jooyeon;Bach, Yoonsoo P.;Seo, Jinguk;Sasago, Hiroshi;Sato, Shuji
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.1
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    • pp.64.2-64.2
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    • 2019
  • It is known that lights scattered by comets and asteroids are partially polarized. From polarimetric observations of those objects, we can investigate physical properties, such as albedos, sizes of cometary dust particles and regolith of asteroids. Since the polarization degrees of those objects highly depend on their phase angles (Sun-object-observer's angles), long-term monitoring observations are required. Moreover, comets show unforeseeable activations (i.e., outbursts) which need follow-up observations to understand the mechanism. In order to realize such monitoring and transient observations, we installed the Triple-Range Imager and POLarimeter (TRIPOL) on the 61cm telescope of Seoul National University (Hereafter, SNU) Gwanak campus. With this combination, we can obtain g', r', i' bands photopolarimetric images simultaneously with $8.0^{\prime}{\times}8.0^{\prime}$ field of view and pixel resolution of 0.94" pixel-1. Here, we make a presentation regarding the photometric and polarimetric performances of TRIPOL on the SNU 61cm telescope. In addition, we introduce initial polarimetric results of asteroid and comets with the instruments. First, we determine the limiting magnitudes (defined as magnitudes for S/N=5) of $15.17{\pm}0.06$ (g'-band), $15.68{\pm}0.01$ (r'-band), $16.24{\pm}0.03$ (I'-band), respectively, with total 240-seconds exposure (four 60-seconds exposure images, each was taken at different rotation angle for the half-wave plate). Second, we found that the instrumental polarization is negligibly small, ($-0.32{\pm}0.04%$ in the g', $-0.36{\pm}0.05%$ in the r' and $-0.21{\pm}0.04%$ in the i'-bands), while the polarization efficiencies are large enough to maximize the performance (i.e., $97.52{\pm}0.03%$ in the g', $98.83{\pm}0.02%$ in the r' and $99.15{\pm}0.02%$ in the i'-bands). With the instruments, we made observations of three Jupiter-family comets, 21P/Giacobini-Zinner, 38P/Stephan-Oterma, and 46P/Wirtanen and plan to observe one near-Earth asteroid, (433) Eros, on a trial basis. Especially for comets, we discriminate signals from dust and gas to eliminate gas contamination, which are known to change observed degree of linear polarization, using multi-band images. We confirm that the phase angle dependency of these comets are consistent with previous observations, probably because polarimetric property of Jupiter-family comets are broadly homogeneous unlike asteroids. We will also describe future observation plans using TRIPOL and SNU 61cm telescope.

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Emotional Labor Factors Affecting Depressive Mood in Occupational Therapists (작업치료사의 우울감에 영향을 미치는 감정노동 요인)

  • Oh, Seo-Yeon;Koo, Jung-Wan
    • Korean Journal of Occupational Therapy
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    • v.26 no.4
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    • pp.1-11
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    • 2018
  • Objective : This study was conducted to determine the emotional labor of occupational therapists and the level of their feelings of depression and to examine the impact of their emotional labor on their depressive mood. Methods : Subjects of this study were clinical occupational therapists working at hospitals and clinics in Seoul and Gyeonggi regions. The factors of emotional labor were set as independent variables, the general characteristic variable and job characteristic variable which showed significant results in the chi-square test was set as the adjusted variable and whether the depression happens or not was set as the dependent variable, after which a multivariate logistic regression analysis was conducted. Results : Components of emotional labor, including frequency of emotional display(OR 1.699, 95% CI 1.202-2.401), attentiveness to required display rules(OR 1.436, 95% CI 1.070-1.982), and emotional dissonance(OR 1.866, 95% CI 1.336-2.607) all had a significant effect on depression. The possibility of depression was significantly higher in women than men(OR 5.736, 95% CI 1.746-18.846), those working for more than 8 hours per day than less than 8 hours per day(OR 8.609, 95% CI 2.306-32.137), and those working with children than those working with adults(OR 4.249, 95% CI 1.668-10.824). Conclusion : This study revealed that the emotional labor that occupational therapists are exposed to while interacting with patients and their caregivers exerts an influence on their feelings of depression. This suggests the need for developing various preventive intervention programs designed to alleviate the depressive symptoms of occupational therapists and formulating appropriate policies.

Evaluation and Predicting PM10 Concentration Using Multiple Linear Regression and Machine Learning (다중선형회귀와 기계학습 모델을 이용한 PM10 농도 예측 및 평가)

  • Son, Sanghun;Kim, Jinsoo
    • Korean Journal of Remote Sensing
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    • v.36 no.6_3
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    • pp.1711-1720
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    • 2020
  • Particulate matter (PM) that has been artificially generated during the recent of rapid industrialization and urbanization moves and disperses according to weather conditions, and adversely affects the human skin and respiratory systems. The purpose of this study is to predict the PM10 concentration in Seoul using meteorological factors as input dataset for multiple linear regression (MLR), support vector machine (SVM), and random forest (RF) models, and compared and evaluated the performance of the models. First, the PM10 concentration data obtained at 39 air quality monitoring sites (AQMS) in Seoul were divided into training and validation dataset (8:2 ratio). The nine meteorological factors (mean, maximum, and minimum temperature, precipitation, average and maximum wind speed, wind direction, yellow dust, and relative humidity), obtained by the automatic weather system (AWS), were composed to input dataset of models. The coefficients of determination (R2) between the observed PM10 concentration and that predicted by the MLR, SVM, and RF models was 0.260, 0.772, and 0.793, respectively, and the RF model best predicted the PM10 concentration. Among the AQMS used for model validation, Gwanak-gu and Gangnam-daero AQMS are relatively close to AWS, and the SVM and RF models were highly accurate according to the model validations. The Jongno-gu AQMS is relatively far from the AWS, but since PM10 concentration for the two adjacent AQMS were used for model training, both models presented high accuracy. By contrast, Yongsan-gu AQMS was relatively far from AQMS and AWS, both models performed poorly.

District-Level Seismic Vulnerability Rating and Risk Level Based-Density Analysis of Buildings through Comparative Analysis of Machine Learning and Statistical Analysis Techniques in Seoul (머신러닝과 통계분석 기법의 비교분석을 통한 건물에 대한 서울시 구별 지진취약도 등급화 및 위험건물 밀도분석)

  • Sang-Bin Kim;Seong H. Kim;Dae-Hyeon Kim
    • Journal of Industrial Convergence
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    • v.21 no.7
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    • pp.29-39
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    • 2023
  • In the recent period, there have been numerous earthquakes both domestically and internationally, and buildings in South Korea are particularly vulnerable to seismic design and earthquake damage. Therefore, the objective of this study is to discover an effective method for assessing the seismic vulnerability of buildings and conducting a density analysis of high-risk structures. The aim is to model this approach and validate it using data from pilot area(Seoul). To achieve this, two modeling techniques were employed, of which the predictive accuracy of the statistical analysis technique was 87%. Among the machine learning techniques, Random Forest Model exhibited the highest predictive accuracy, and the accuracy of the model on the Test Set was determined to be 97.1%. As a result of the analysis, the district rating revealed that Gwangjin-gu and Songpa-gu were relatively at higher risk, and the density analysis of at-risk buildings predicted that Seocho-gu, Gwanak-gu, and Gangseo-gu were relatively at higher risk. Finally, the result of the statistical analysis technique was predicted as more dangerous than those of the machine learning technique. However, considering that about 18.9% of the buildings in Seoul are designed to withstand the Seismic intensity of 6.5 (MMI), which is the standard for seismic-resistant design in South Korea, the result of the machine learning technique was predicted to be more accurate. The current research is limited in that it only considers buildings without taking into account factors such as population density, police stations, and fire stations. Considering these limitations in future studies would lead to more comprehensive and valuable research.

Analysis of Runoff Reduction Effect of Flood Mitigation Policies based on Cost-Benefit Perspective (비용-편익을 고려한 홍수 대응 정책의 유출 저감 효과 분석)

  • Jee, Hee Won;Kim, Hyeonju;Seo, Seung Beom
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.43 no.6
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    • pp.721-733
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    • 2023
  • As the frequency of extreme rainfall events increase due to climate change, climate change adaptation measures have been proposed by the central and local governments. In order to reduce flood damage in urban areas, various flood response policies, such as low impact development techniques and enhancement of the capacity of rainwater drainage networks, have been proposed. When these policies are established, regional characteristics and policy-effectiveness from the cost-benefit perspective must be considered for the flood mitigation measures. In this study, capacity enhancement of rainwater pipe networks and low impact development techniques including green roof and permeable pavement techniques are selected. And the flood reduction effect of the target watershed, Gwanak campus of Seoul National University, was analyzed using SWMM model which is an urban runoff simulation model. In addition, along with the quantified urban flooding reduction outputs, construction and operation costs for various policy scenarios were calculated so that cost-benefit analyses were conducted to analyze the effectiveness of the applied policy scenarios. As a result of cost-benefit analysis, a policy that adopts both permeable pavement and rainwater pipe expansion was selected as the best cost-effective scenario for flood mitigation. The research methodology, proposed in this study, is expected to be utilized for decision-making in the planning stage for flood mitigation measures for each region.

Clinical evaluation of the removable partial dentures with implant fixed prostheses (임플란트 고정성 보철물을 이용한 가철성 국소의치의 합병증에 관한 임상적 평가)

  • Kang, Soo-Hyun;Kim, Seong-Kyun;Heo, Seong-Joo;Koak, Jai-Young;Lee, Joo-Hee;Park, Ji-Man
    • The Journal of Korean Academy of Prosthodontics
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    • v.54 no.3
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    • pp.239-245
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    • 2016
  • Purpose: The purpose of this study was to identify clinical complications in removable partial denture (RPD) with implant-supported surveyed prostheses, and to analyze the factors associated with the complications such as location of the implant, splinting adjacent prostheses, the type of retentive clasps, Kennedy classification, and opposing dentition. Materials and Methods: A retrospective clinical study was carried out for 11 patients (7 male, 4 female), mean age of 67.5, who received RPD with Implant-supported surveyed prostheses between 2000 and 2016. The mechanical complications of 11 RPDs and 37 supporting implant prostheses and the state of natural teeth and peripheral soft tissue were examined. Then the factors associated with the complications were analyzed. Results: The average of 3.4 implant-supported prostheses were used for each RPD. Complications found during the follow-up period of an average of 42.1 months were in order of dislodgement of temporary cement-retained prostheses, opposing tooth fracture/mobility, screw fracture/loosening, clasp loosening, veneer porcelain fracture, marginal bone resorption and mobility of implant, artificial tooth fracture. Complications occurred more frequently in anterior region compared to posterior region, non-splinted prostheses compared to splinted prostheses, surveyed prostheses applied by wrought wire clasp compared to other clasps, and natural dentition compared to other removable prostheses as opposing dentition. There were no significant differences in complications according to the Kennedy classification. Conclusion: All implant-assisted RPD functioned successfully throughout the follow-up. However, further clinical studies are necessary because the clinical evidences are still not enough to guarantee the satisfactory prognosis of implant-assisted RPD for long-term result.

The effect of job stress on organizational commitment for senior welfare facility staffs suffering from emotional labor (노인복지시설 종사자의 감정노동으로 인한 직무스트레스가 조직몰입에 미치는 영향)

  • Cho, Jong-hyeon
    • Journal of Venture Innovation
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    • v.1 no.1
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    • pp.129-143
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    • 2018
  • When consulting with senior service user or his or her family members, employees of senior welfare facilities face a vertical relationship due to age rather than a horizontal relationship. Despite few cases reported, service users and the families afflict physical and mental pain on the employees through irrational demands, physical abuses, and verbal abuses. In particular, the Korean society has advocated the notion of respecting elders and thus emphasized members of society to provide unconditional support to those of old age. In reality, however, people who work at senior welfare facilities report the difficulty of providing supports to heavy demands in selfish complaints that are often impossible to fulfill. Starting from May 2018, there has been a petition to the Korean Blue House, seeking protective measures for 'Senior welfare facility professions who are exposed to violence'. The study conduct researches on the effect of job stress on the organizational commitment for senior welfare facility employees from suffering emotional labor. Furthermore, it also aims to point the difficulties that the professions face and the solutions that alleviate the conflicts between the rights of services users of senior welfare facilities and its staffs. The study surveyed 178 staffs who work in senior welfare facilities in Seoul and Gyeonggi Province as its research method. The collected data was analyzed by using IBM SPSS Statistics 24.0 to derive the general characteristics of the sample, reliability, feasibility analysis, correlation analysis, and verification of the research hypothesis. The study was able to conclude the following: First, the frequency of emotional expression of senior welfare facility staffs had negative(-) influences on job stress. Second, the incongruity of emotions of senior welfare facility staffs had negative(-) influences on job stress. Third, the incongruity of emotions of senior welfare facility staffs had negative (-) influences on job stress. Fourth, the job stress showed mediating effects between emotional labor factors and organizational commitment

An in vitro study of mesenchymal stem cell proliferation on titanium discs coated with rhTGF-β2/PLGA by electrospray (Electrospray법으로 rhTGF-β2/PLGA 복합체를 코팅한 티타늄에서의 간엽줄기세포 증식에 관한 연구)

  • Kim, Joohyung;Kim, Seong-Kyun;Heo, Seong-Joo;Koak, Jai-Young;Lee, Woo-Sung;Lee, Joo-Hee;Park, Ji-Man
    • The Journal of Korean Academy of Prosthodontics
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    • v.54 no.2
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    • pp.120-125
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    • 2016
  • Purpose: The purpose of this study is to identify the effect of mesenchymal stem cell proliferation on recombinant human transforming growth factor-beta (rhTGF-${\beta}2$) / poly (D,L-lactide-co-glycolide) (PLGA) treated titanium discs by electrospray. Materials and methods: Anodized titanium surface coated with PLGA was used for a control group to compare anodized titanium surface coated with 125 ng/ml and 500 ng/ml rhTGF-${\beta}2$ as test groups. Atomic force microscope (AFM) test was utilized to determine the difference in coating surface roughness, and field-emission scanning electron microscopy (FE-SEM) was taken to visualize even distribution of coating particles on titanium discs. The mesenchymal stem cell proliferation was tested by using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl-tetrazolium bromide) assay on 1st, 4th, 7th days. Results: According to AFM results, there was no statistically significant difference in titanium discs treated with PLGA and with rhTGF-${\beta}2$/PLGA (P>.05). MTT assay test results showed that there was statistically significant difference in mesenchymal stem cell proliferation on test groups compared to control groups at 7th day, and cell viability on discs coated with rhTGF-${\beta}2$ was significantly higher than control groups (P<.05). Conclusion: Titanium surface coated with rhTGF-${\beta}2$/PLGA shows statistically significant higher cell proliferation and the titanium surface coated with the higher concentration of rhTGF-${\beta}2$ presents faster cell growth activity.

Difference in the Sense of Community in Open-Structure Central Squares in Apartment Complexes (공동주택 중앙광장의 개방 구조에 따른 지역 공동체의식의 차이)

  • Kang, Yon-Ju;Park, Jong-Wan;Im, Seung-Bin
    • Journal of the Korean Institute of Landscape Architecture
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    • v.37 no.3
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    • pp.21-32
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    • 2009
  • As an alternative for restoring a sense of community which has been broken up due to urban residence redevelopment, this study focuses on structural characteristics according to physical location of central squares in apartment complexes. Central squares do not simply function as inner-aiming and self-completed spaces for the residents, but their role can be expanded to a core location which encourages neighbors to communicate and interact with each other. The suppositions for this study are as follows. Structural characteristics according to the physical locations of the central squares in apartment complexes affect apartment residents' openness toward their neighbors and non-residents' accessibility to the square. At the same time, it influences the sense of community. In addition, psychological distance which is represented as psychological openness and accessibility forms a reciprocal relationship with the sense of community. For the study, we first categorized central squares as either open-structure or closed-structure based on how accessible it is from outside the apartment complex. According to these types of central squares, Sillim Prugio, Banghak Deasang Town Hyundai, Gwanak Prugio and Banghak Samsung Raemian 1 which have similar conditions and different structures were selected as sites of the study. Then each apartment complex was classified by apartment residents and non-residents so that eight groups were prepared for the survey. The results of the questionnaire survey especially regarding measuring the sense of community, psychological openness and accessibility indicated that the suppositions were right. Hence, the sense of community, psychological openness and accessibility are high in a central square with an open-structure while high standards of psychological openness and accessibility guarantee a positive sense of community. This study is meaningful in that it verifies that the physical location of central squares is reciprocally related to psychological openness, accessibility and a sense of community. At the same time, this study may serve as theoretical grounds for the planning and construction of practical central squares.