• Title/Summary/Keyword: Three-moment model

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The Effects of Astragali Radix on Hypothyroidism Rat Model Induced by 6-Propyl-2-thiouracil(PTU) (황기가 6-Propyl-2-thiouracil(PTU)로 유발된 rat의 갑상선기능저하증에 미치는 영향)

  • Lee, Ji Hye;Koo, Jin Suk;Roh, Seong Soo;Park, Ji Ha;Seo, Bu Il
    • The Korea Journal of Herbology
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    • v.34 no.3
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    • pp.45-53
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    • 2019
  • Objectives : In present study, we investigated a therapeutic effect of Astragali Radix on hypothyroidism rat model induced by 6-Propyl-2-thiouracil (PTU). Methods : Six-week-old male Sprague-Dawley rats were divided into five groups : Group one included the normal mice. Group two was administrated PTU. Group three and four were administrated the aqueous extract of Astragali Radix 150 and 300 mg/kg before start of PTU treatment. Group five (Positive control) was administrated with levothyroxine 0.5 mg/kg. During this moment the body weight, liver $H_2O_2$ and catalase (CAT) amount, serum thyroid hormone, serum asparte aminotransferase (AST) and alanine aminotransferase (ALT), gland weights were measured with histopathological changes of thyroid glands. These results were compared with levothyroxine 0.5 mg/kg treated rats. Results : The PTU treatment lead to marked decreases of body weight, level of thyroid hormone in serum and liver CAT activation. Also, PTU treatment increased thyroid gland weight, thyroid gland hormone TSH, liver $H_2O_2$ amount and level of AST in serum. On the other hands, the administration of Astragali Radix extract increased body weight gains and ameliorated histopathological changes of thyroid such as hyperplasia of follicular cells with of follicular colloid contents and sizes. In addition, the administration of Astragali Radix extract increased level of $T_4$ in serum, CAT activation in liver. Moreover, the administration of Astragali Radix extract decreased levels of TSH and AST in serum and $H_2O_2$ amount in liver Conclusions : This study suggests that Astragali Radix extract has therapeutic effects on hypothyroidism via promoting thyroid hormone production.

Corporate Default Prediction Model Using Deep Learning Time Series Algorithm, RNN and LSTM (딥러닝 시계열 알고리즘 적용한 기업부도예측모형 유용성 검증)

  • Cha, Sungjae;Kang, Jungseok
    • Journal of Intelligence and Information Systems
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    • v.24 no.4
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    • pp.1-32
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    • 2018
  • In addition to stakeholders including managers, employees, creditors, and investors of bankrupt companies, corporate defaults have a ripple effect on the local and national economy. Before the Asian financial crisis, the Korean government only analyzed SMEs and tried to improve the forecasting power of a default prediction model, rather than developing various corporate default models. As a result, even large corporations called 'chaebol enterprises' become bankrupt. Even after that, the analysis of past corporate defaults has been focused on specific variables, and when the government restructured immediately after the global financial crisis, they only focused on certain main variables such as 'debt ratio'. A multifaceted study of corporate default prediction models is essential to ensure diverse interests, to avoid situations like the 'Lehman Brothers Case' of the global financial crisis, to avoid total collapse in a single moment. The key variables used in corporate defaults vary over time. This is confirmed by Beaver (1967, 1968) and Altman's (1968) analysis that Deakins'(1972) study shows that the major factors affecting corporate failure have changed. In Grice's (2001) study, the importance of predictive variables was also found through Zmijewski's (1984) and Ohlson's (1980) models. However, the studies that have been carried out in the past use static models. Most of them do not consider the changes that occur in the course of time. Therefore, in order to construct consistent prediction models, it is necessary to compensate the time-dependent bias by means of a time series analysis algorithm reflecting dynamic change. Based on the global financial crisis, which has had a significant impact on Korea, this study is conducted using 10 years of annual corporate data from 2000 to 2009. Data are divided into training data, validation data, and test data respectively, and are divided into 7, 2, and 1 years respectively. In order to construct a consistent bankruptcy model in the flow of time change, we first train a time series deep learning algorithm model using the data before the financial crisis (2000~2006). The parameter tuning of the existing model and the deep learning time series algorithm is conducted with validation data including the financial crisis period (2007~2008). As a result, we construct a model that shows similar pattern to the results of the learning data and shows excellent prediction power. After that, each bankruptcy prediction model is restructured by integrating the learning data and validation data again (2000 ~ 2008), applying the optimal parameters as in the previous validation. Finally, each corporate default prediction model is evaluated and compared using test data (2009) based on the trained models over nine years. Then, the usefulness of the corporate default prediction model based on the deep learning time series algorithm is proved. In addition, by adding the Lasso regression analysis to the existing methods (multiple discriminant analysis, logit model) which select the variables, it is proved that the deep learning time series algorithm model based on the three bundles of variables is useful for robust corporate default prediction. The definition of bankruptcy used is the same as that of Lee (2015). Independent variables include financial information such as financial ratios used in previous studies. Multivariate discriminant analysis, logit model, and Lasso regression model are used to select the optimal variable group. The influence of the Multivariate discriminant analysis model proposed by Altman (1968), the Logit model proposed by Ohlson (1980), the non-time series machine learning algorithms, and the deep learning time series algorithms are compared. In the case of corporate data, there are limitations of 'nonlinear variables', 'multi-collinearity' of variables, and 'lack of data'. While the logit model is nonlinear, the Lasso regression model solves the multi-collinearity problem, and the deep learning time series algorithm using the variable data generation method complements the lack of data. Big Data Technology, a leading technology in the future, is moving from simple human analysis, to automated AI analysis, and finally towards future intertwined AI applications. Although the study of the corporate default prediction model using the time series algorithm is still in its early stages, deep learning algorithm is much faster than regression analysis at corporate default prediction modeling. Also, it is more effective on prediction power. Through the Fourth Industrial Revolution, the current government and other overseas governments are working hard to integrate the system in everyday life of their nation and society. Yet the field of deep learning time series research for the financial industry is still insufficient. This is an initial study on deep learning time series algorithm analysis of corporate defaults. Therefore it is hoped that it will be used as a comparative analysis data for non-specialists who start a study combining financial data and deep learning time series algorithm.

When sense, liturgy, and story meet children's spirituality (감각, 예전, 이야기가 어린이영성과 만날 때)

  • Kum Hee Yang
    • Journal of Christian Education in Korea
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    • v.76
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    • pp.27-49
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    • 2023
  • Purpose of study: The purpose of this paper is to gain insight into the alternative possibility of Christian children's education overcoming the current church school paradigm namely schooling system by examining the characteristics and the direction of children's spiritual education. Research content and method: This paper is a review of the characteristics of children's spiritual education and ways to embody those characteristics. Therefore, it consists of two parts: the characteristics of children's spiritual education and the search for ways to embody those characteristics. First, children's spiritual education is a "formative" model that aims to form children's spirituality based on children's spirituality research that views children as 'spiritual beings.' This model specifically has three core orientations: 'experience', 'meeting God', and 'immersion'. In other words, children's spiritual education pursues 'experience rather than knowledge', pursues the experience of meeting God in the second person rather than teaching third-person knowledge about God, and values the spiritual moment of immersion more than anything else. Second, it searches for specific ways and methods through which those three core goals could be implemented, and found that they were 'sense,' 'liturgy,' and 'story.' The sense becomes a path that evokes experience, the liturgy becomes a place for 'meeting God,' and 'story' becomes a key path to 'immersion.' And when the three are organically combined with each other, the goals pursued by children's spiritual education can be holistically converged. Conclusions and Suggestions: Through these considerations, it found that the core values and direction of education are consistently maintained in children's spiritual education, from children's understanding to education methods. It also figured out that the direction should be shared not only by children's spiritual education but also by all who pursue holistic faith education: 'what to experience' rather than 'what to teach', 'liturgy' rather than 'teaching', 'story' rather than 'explanation', and 'sensory' experiences rather than 'abstract' knowledge.

A Study for Shear Deterioration of Reinforced Concrete Beam-Column Joints Failing in Shear after Flexural Yielding of Adjacent Beams (보의 휨항복 후 접합부가 파괴하는 철근콘크리트 보-기둥 접합부의 전단내력 감소에 대한 해석적 연구)

  • Park, Jong-Wook;Yun, Seok-Gwang;Kim, Byoung-Il;Lee, Jung-Yoon
    • Journal of the Korea Concrete Institute
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    • v.24 no.4
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    • pp.399-406
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    • 2012
  • Beam-column joints are generally recognized as the critical regions in the moment resisting reinforced concrete (RC) frames subjected to both lateral and vertical loads. As a result of severe lateral load such as seismic loading, the joint region is subjected to horizontal and vertical shear forces whose magnitudes are many times higher than in column and adjacent beam. Consequently, much larger bond and shear stresses are required to sustain these magnified forces. The critical deterioration of potential shear strength in the joint area should not occur until ductile capacity of adjacent beams reach the design demand. In this study, a method was provided to predict the deformability of reinforced concrete beam-column joints failing in shear after the plastic hinges developed at both ends of the adjacent beams. In order to verify the deformability estimated by the proposed method, an experimental study consisting of three joint specimens with varying tensile reinforcement ratios was carried out. The result between the observed and predicted behavior of the joints showed reasonably good agreement.

A Study on Residual Strength Assessment of Damaged Oil Tanker by Smith Method (Smith법에 의한 손상 유조선의 잔류강도 평가 연구)

  • Ahn, Hyung-Joon;Baek, Deok-Pyo;Lee, Tak-Kee
    • Journal of Navigation and Port Research
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    • v.35 no.10
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    • pp.823-827
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    • 2011
  • The present Common Structural Rules for double hull oil tanker is not included the residual strength, which is one of the functional requirements in design part of Goal-based new ship construction standards (GBS). The GBS will be enforced after July 1, 2016. The requirement related residual strength has the goal to build safe ship even if she has the specified damages due to marine accidents including collision and grounding. In order to assess the residual strength based on risk for structural damages according to GBS, tons of nonlinear FE analysis work taking into account various types of damage will be needed. The Smith's method, a kind of simplified method for the strength analysis is very useful for this purpose. In this paper, the residual strength assessments based on ultimate strength using Smith's method were carried out. The objected ship is VLCC with stranding damage in bottom structures. Also, the results were compared with that of nonlinear FE analysis using three cargo hold model.

Analytical Study on the Prying Action Force and Axial Tensile Stiffness of High-Strength Bolts Used in an Unstiffened Extended End-Plate Connection (비보강 확장단부판 접합부에 체결된 고장력볼트의 지레작용력 및 축방향 인장강성에 대한 해석적 연구)

  • Kim, Hee Dong;Yang, Jae Guen;Lee, Hyung Dong
    • Journal of Korean Society of Steel Construction
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    • v.27 no.2
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    • pp.251-260
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    • 2015
  • The end plate connection is applied to beam-column moment connections in various forms. Such end plate connection displays changes in the behavioral characteristics, strength and stiffness, and energy dissipation capacity based on the thickness and length of the end plate, the number and diameter of the high strength bolt, the gauge distance of the high strength bolt, prying action force of the high strength bolt, and dimensions and length of the welds. Accordingly, this study has apprehended the axial tensile stiffness and prying action force of the high strength bolt connected on the tensile side based on the difference in thickness of the end plate, and was conducted to propose an analysis model for the prediction of such variables that affect the operating properties of the end plate. To achieve this, this study has conducted a three-dimensional non-linear finite-element analysis of the unstiffened expanding end plate connection by selecting only the thickness of the end plate as the variable.

Estimating design floods for ungauged basins in the geum-river basin through regional flood frequency analysis using L-moments method (L-모멘트법을 이용한 지역홍수빈도분석을 통한 금강유역 미계측 유역의 설계홍수량 산정)

  • Lee, Jin-Young;Park, Dong-Hyeok;Shin, Ji-Yae;Kim, Tae-Woong
    • Journal of Korea Water Resources Association
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    • v.49 no.8
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    • pp.645-656
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    • 2016
  • The study performed a regional flood frequency analysis and proposed a regression equation to estimate design floods corresponding to return periods for ungauged basins in Geum-river basin. Five preliminary tests were employed to investigate hydrological independence and homogeneity of streamflow data, i.e. the lag-one autocorrelation test, time homogeneity test, Grubbs-Beck outlier test, discordancy measure test ($D_i$), and regional homogeneity measure (H). The test results showed that streamflow data were time-independent, discordant and homogeneous within the basin. Using five probability distributions (generalized extreme value (GEV), three-parameter log-normal (LN-III), Pearson type 3 (P-III), generalized logistic (GLO), generalized Pareto (GPA)), comparative regional flood frequency analyses were carried out for the region. Based on the L-moment ratio diagram, average weighted distance (AWD) and goodness-of-fit statistics ($Z^{DIST}$), the GLO distribution was selected as the best fit model for Geum-river basin. Using the GLO, a regression equation was developed for estimating regional design floods, and validated by comparing the estimated and observed streamflows at the Ganggyeong station.

Segmentation Method of Overlapped nuclei in FISH Image (FISH 세포영상에서의 군집세포 분할 기법)

  • Jeong, Mi-Ra;Ko, Byoung-Chul;Nam, Jae-Yeal
    • The KIPS Transactions:PartB
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    • v.16B no.2
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    • pp.131-140
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    • 2009
  • This paper presents a new algorithm to the segmentation of the FISH images. First, for segmentation of the cell nuclei from background, a threshold is estimated by using the gaussian mixture model and maximizing the likelihood function of gray value of cell images. After nuclei segmentation, overlapped nuclei and isolated nuclei need to be classified for exact nuclei analysis. For nuclei classification, this paper extracted the morphological features of the nuclei such as compactness, smoothness and moments from training data. Three probability density functions are generated from these features and they are applied to the proposed Bayesian networks as evidences. After nuclei classification, segmenting of overlapped nuclei into isolated nuclei is necessary. This paper first performs intensity gradient transform and watershed algorithm to segment overlapped nuclei. Then proposed stepwise merging strategy is applied to merge several fragments in major nucleus. The experimental results using FISH images show that our system can indeed improve segmentation performance compared to previous researches, since we performed nuclei classification before separating overlapped nuclei.

The study on the effect of fracture zone and its orientation on the behavior of shield TBM cable tunnel (단층파쇄대 규모 및 조우 조건에 따른 전력구 쉴드 TBM 터널의 거동 특성 분석)

  • Cho, Won-Sub;Song, Ki-Il;Kim, Kyoung-Yul
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.16 no.4
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    • pp.403-415
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    • 2014
  • Recently, the temperature rise in the summer due to climate change, power usage is increasing rapidly. As a result, power generation facilities have been newly completed and the need for ultra-high-voltage transmission line for power transmission of electricity to the urban area has increased. The mechanized tunnelling method using a shield TBM have an advantage that it can minimize vibrations transmitted to the ground and ground subsidence as compared with the conventional tunnelling method. Despite the popularity of shield TBM for cable tunnel construction, study on the mechanical behavior of cable tunnel driven by shield TBM is insufficient. Thus, in this study, the effect of fractured zone ahead of tunnel face on the mechanical behavior of the shield TBM cable tunnel is investigated. In addition, it is intended to compare the behavior characteristics of the fractured zone with continuous model and applying the interface elements. Tunnelling with shield TBM is simulated using 3D FEM. According to the change of the direction and magnitude of the fractured zone, Sectional forces such as axial force, shear force and bending moment are monitored and vertical displacement at the ground surface is measured. Based on the stability analysis with the results obtained from the numerical analysis, it is possible to predict fractured zone ahead of the shield TBM and ensure the stability of the tunnel structure.

Hydrological homogeneous region delineation for bivariate frequency analysis of extreme rainfalls in Korea (다변량 L-moment를 이용한 이변량 강우빈도해석에서 수문학적 동질지역 선정)

  • Shin, Ju-Young;Jeong, Changsam;Joo, Kyungwon;Heo, Jun-Haeng
    • Journal of Korea Water Resources Association
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    • v.51 no.1
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    • pp.49-60
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    • 2018
  • The multivariate regional frequency analysis has many advantages such as an adaption of regional parameters and consideration of a correlated structure of the data. The multivariate regional frequency analysis can provide the broader and more detailed information for the hydrological variables. The multivariate regional frequency analysis has not been attempted to model hydrological variables in South Korea yet. Therefore, it is required to investigate the applicability of the multivariate regional frequency analysis in the modeling of the hydrological variables. The current study investigated the applicability of the homogeneous region delineation and their characteristics in bivariate regional frequency analysis of annual maximum rainfall depth-duration data. The K-medoid method was employed as a clustering method. The discordancy and heterogeneous measures were used to assess the appropriateness of the delineation results. According to the results of the clustering analysis, the employed stations could be grouped into five regions. All stations at three of the five regions led to acceptable values of discordancy measures than the threshold. The stations where have short record length led to the large discordancy measures. All grouped regions were identified as a homogeneous region based on heterogeneous measure estimates. It was observed that there are strong cross-correlations among the stations in the same region.