• Geotechnical Engineering
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• v.8 no.2
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• pp.5-20
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• 1992

The physical-based and lumped-parameter hydrologic groundwater flow model for predicting the rainfall-triggered rise of groundwater levels in hillside slopes is developed in this paper to assess the risk of landslides. The developed model consists of a vertical infiltration model for unsaturated zone linked to a linear storage reservoir model(LSRM) for saturated zone. The groundwater flow model has uncertain constants like soil depttL slope angle, saturated permeability, and potential evapotranspiration and four free model parameters like a, b, c, and K. The free model parameters could be estimated from known input-output records. The BARD algorithm is uses as the parameter estimation technique which is based on a linearization of the proposed model by Gauss -Newton method and Taylor series expansion. The application to examine the capacity of prediction shows that the developed model has a potential of use in forecast systems of predicting landslides and that the optimal estimate of potential 'a' in infiltration model is the most important in the global optimum analysis because small variation of it results in the large change of the objective function, the sum of squares of deviations of the observed and computed groundwater levels. 본 논문에서는 가파른 산사면에서 산사태의 발생을 예측하기 위한 수문학적 인 지하수 흐름 모델을 개발하였다. 이 모델은 물리적인 개념에 기본하였으며, Lumped-parameter를 이용하였다. 개발된 지하수 흐름 모델은 두 모델을 조합하여 구성되어 있으며, 비포화대 흐름을 위해서는 수정된 abcd 모델을, 포화대 흐름에 대해서는 시간 지체 효과를 고려할 수 있는 선형 저수지 모델을 이용하였다. 지하수 흐름 모델은 토층의 두께, 산사면의 경사각, 포화투수계수, 잠재 증발산 량과 같은 불확실한 상수들과 a, b, c, 그리고 K와 같은 자유모델변수들을 가진다. 자유모델변수들은 유입-유출 자료들로부터 평가할 수 있으며, 이를 위해서 본 논문에서는 Gauss-Newton 방법을 이용한 Bard 알고리즘을 사용하였다. 서울 구로구 시흥동 산사태 발생 지역의 산사면에 대하여 개발된 모델을 적용하여 예제 해석을 수행함으로써, 지하수 흐름 모델이 산사태 발생 예측을 위하여 이용할 수 있음을 입증하였다. 또한, 매개변수분석 연구를 통하여, 변수 a값은 작은 변화에 대하여 목적함수값에 큰 변화를 일으키므로 a의 값에 대한 최적값을 구하는 것이 가장 중요한 요소라는 결론을 얻었다.

• Proceedings of KOSOMES biannual meeting
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• 2007.05a
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• pp.15-20
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• 2007

In this study, the authors investigated the change of marine environment by dumping dredged materials generated by construction of Busan New Port. There are lots of possibilities to impact an ocean ecosystem by toxic materials in the dredged material dumped in the open seas. As a result of analysis of environmental monitoring in the study areas 12 times a year, COD is II grade, T-N is I grade, T-P is between II and III grade. This result is same as another results of offshore in Korea. It seems unclear that it results from the change of water quality by dumping dredged material. However, according to the result of this investigation, it is not effected extensively to the marine environment by dumping dredged materials. We need further environmental monitoring in the interest sea areas, also need to keep on investigating the impact on the marine ecosystem by dumping dredged materials.

• Geophysics and Geophysical Exploration
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• v.11 no.2
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• pp.93-98
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• 2008

Abstract: Surface topography has a significant influence on seismic wave propagation in a reflection seismic exploration. Effects of surface topography on two-dimensional elastic wave propagation are investigated through modeling using a weighted-averaging (WA) finite-element method (FEM), which is computationally more efficient than conventional FEM. Effects of air layer on wave propagation are also investigated using flat surface models with and without air. To validate our scheme in modeling including topography, we compare WA FEM results for irregular topographic models against those derived from conventional FEM using one set of rectangular elements. For the irregular surface topography models, elastic wave propagation is simulated to show that breaks in slope act as a new source for diffracted waves, and that Rayleigh waves are more seriously distorted by surface topography than P-waves.

• Elastomers and Composites
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• v.34 no.2
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• pp.135-146
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• 1999

The thermal degradation kinetics of SBR and tire were studied using a conventional thermogravimetric analysis in the stream nitrogen at a heating rate of 5, 10, 15, $20^{\circ}C/min$, respectively. Thermogravimetric curves and their derivatives were analyzed using various analytical methods to determine the kinetic parameters. The degradation of the SBR and tire was found to be a complex process which has multi-stages. The Friedman method gave average activation energies for the SBR and tire of 247.53kJ/mol and 230.00kJ/mol, respectively. Mean-while, the Ozawa method Eave 254.80kJ/mol and 215.76kJ/mol. It would appear that either. Friedman's differential method or Ozawa's integral method provided satisfactory mathematical approaches to determine the kinetic parameters for the degradation of the SBR and tire. Approximately 86% and 55% of oil products were obtained at a final temperature of $700^{\circ}C$ and a heating rate of $20^{\circ}C/min$ for the SBR and tire respectively.

• Spatial Information Research
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• v.23 no.2
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• pp.49-57
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• 2015

Recently, Through the linkage and opening, the fusion of the spatial information, it is necessary for productive ecosystem to provide a variety of information and to increase the civil use. Depending on the economic growth, demand for quality of life and well-being has been on the increase. Spatial information service contents for the public convenience has emerged to solve the problem such as health, safety, welfare and discomfort of daily life This study aims to implement search services for a tailored residence space through the three-dimensional data modeling on cadastral information. To achieve this goal, we established the requirements for deriving a registered object by investigating recent trend with respect to existing cadastral data model and defined property and relationship. Focusing on Songpa-gu, Jamsil station in Seoul, we implemented search services for a tailored residence space for three-dimensional right analysis in conjunction with residential and commercial complex building. As a result, we derived a way to supply 3D cadastre information through open platforms (VWorld) and to represent efficiently, which is able to improve the quality of spatial information service contents for the public convenience as well as to widen utilization of information.

• Spatial Information Research
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• v.23 no.2
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• pp.21-29
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• 2015

Recently, according to the increasingly populated data, many media and organizations focus on big data, data visualization, information visualization and infographics. Domestically, Chosun.com and Hankyoreh online have improved on the data visualization field and internationally, the Guardian, Wall Street Journal, and New York Times are the leading companies on that area. Until now, many people have recognized infographics as a design-oriented product in Korea. However, one of significant data visualization programs, Tableau Public, can visualize data more efficiently. In this paper, Data Visualization Methods Quadrant for Policy Making is defined, and data analysis and producing infographics are executed. As used data, World Bank open source was adopted and using the number of passenger cars per 1,000 people, two analysis results are extracted. First, in high income group, the more GNI per capita, the lesser Slope is represented and in mid income group, the more GNI per capita positively affects to Slope. Second, in the global finance crisis, the car ownership rate was about 1.7 times than the usual state in the global economy. Through the case study, this paper suggests that the direction of producing infographics should be changed from design-oriented to data-oriented. Moreover, the data-oriented infographics should be propagated as means of scientific research and policy making.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.2
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• pp.89-103
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• 2020

As we face an aging society, the demand for personal mobility for disabled and aged people is increasing. In fact, as of 2017, the number of electric wheelchair in the country continues to increase to 90,000. However, people with disabilities and seniors are more likely to have accidents while driving, because their judgment and coordination are inferior to normal people. One of the causes of the accident is the interference of personal vehicle steering control due to unbalanced road surface conditions. In this paper, we introduce a encoder type semantic segmentation algorithm that can recognize road conditions at high speed to prevent such accidents. To this end, more than 1,500 training data and 150 test data including road surface damage were newly secured. With the data, we proposed a deep neural network composed of encoder stages, unlike the Auto-encoding type consisting of encoder and decoder stages. Compared to the conventional method, this deep neural network has a 4.45% increase in mean accuracy, a 59.2% decrease in parameters, and an 11.9% increase in computation speed. It is expected that safe personal transportation will be come soon by utilizing such high speed algorithm.

• Journal of Science and Technology Studies
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• v.12 no.1
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• pp.107-144
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• 2012

Recently concerns on the energy future are rising in Korea after nuclear disaster of Fukushima in Japan last year. However, even after Fukushima disaster Korean government keeps on insisting nuclear oriented energy policy. Contrary to it, some of civil society's organizations(CSOs) including environment groups and progressive political parties are making strong voices for phase-out nuclear. As a way of phase-out nuclear activity researcher groups based on CSOs have presented several alternative energy scenarios against the official government scenario so that contest between the two senarios seems not to be avoided. This article aims to analyse the politics of expertise around energy scenarios in Korea by highlighting differences between two scenarios of government and CSOs in terms of epistemological and methodological base, value orientation, institutional foundation, and the socio-political contexts of scenarios. Our research shows that government's energy scenario is based on scientific-positivist epistemology, firm belief in value neutrality and forecasting method, and is built by neo-classical economists at government-sponsored research institutes in accordance with the 'Business As Usual' approach. In contrast, alternative scenarios of CSOs can be said to be based on epistemological constructivism, value oriented attitudes and backcasting method, and be built by collaboration of researchers and activists with different academic and social backgrounds after Fukushima nuclear disaster.

• Journal of Science and Technology Studies
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• v.14 no.2
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• pp.1-48
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• 2014

Recently, governance of science and technology emerged as one of most important social problems and as a result it is crucial to understand it in science and technology studies. This article discusses three most important realms in science and technology goverance - research and development, regulation, and social movement - in the concrete Korean contexts. First of all, the Korean state has driven research and development and promoted its commercialization unlike other developed countries. Consequently, this nationalistic view on science disseminated to Korean public and it generated uniformity in research style and organization. Second, science and technology regulations embraced developed countries' policies, leading to its glocalization. As a result, technocratic old governance and new governance including precautionary principle and participatory democracy coexist. Third, the civil society has challenged expertise and state-driven science and technology governance and fueled social movements related to environment, safety, and health issues. The politics of knowledge created by citizens' voluntary participation and collaborative experts made it clear that science and technology should be no longer tool for economic development. In conclusion, we discuss characteristics of science and technology governance in Korea, giving various implication on current research and policy.

• Korean Journal of Social Welfare
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• v.57 no.4
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• pp.5-33
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• 2005

In order to examine the causes of the social policy changes in Korea during the late of 1990s, this study tries to compare the social policy decision-making structure between Kim Yong-Sam Government and Kim Dae-Jung Government. This study applies policy network analysis method which measures the relation and power structures of policy actors and as a result shows the characteristics of the policy making structure. Analysing the 6 policy domains and 52 policy events, this study finds that the importance and location of veto points which were created by the social policy decision processes have changed. In Korea, social policy decision processes have been produced power structures in which Ministry of Finance and Economic Planning Board have played a decisive role. In result, these executives can have controlled policy making processes and had veto power, i. e. veto points in policy decision-making structure. But, during Kim Dae-Jung government, accountability issues of financial crisis and reorganization of ministries have changed the importance and location of veto points. Pro-welfare groups of civil society got a chance to penetrate policy decision-making structure during that time. This study argues that these changes of policy decision-making structure may be associated with the social policy changes in Korea during the late of 1990s.