건강분야 사회적 배제 변화추이

신호성 한국보건사회연구원 2009 보건·복지 Issue&Focus Vol.16 No.-

한국의료패널 자료를 통해 살펴본 입원의료이용의 수도권 및 상급종합병원 집중 현상

신호성 대한의사협회 의료정책연구소 2015 의료정책포럼 Vol.13 No.1

지중 열교환 시스템을 위한 열-수리 파이프 요소의 개발

신호성,이승래 한국지반공학회 2013 한국지반공학회논문집 Vol.29 No.8

Ground-coupled heat pump system has attracted attention as a promising renewable energy technology due to its improving energy efficiency and eco-friendly mechanism for space cooling and heating. Pipes buried in the ground play a role of direct thermal interaction between circulating fluid inside the pipe and surrounding soils in the geothermal exchange system. However, both complexities of turbulent flow coupling thermal-hydraulic phenomena and very long aspect ratio of the pipe make it difficult to model the heat exchange system directly. Energy balance for fluid flow inside the pipe was derived to model thermal-hydraulic phenomena, and one-dimensional pipe element was proposed through Galerkin formation and time integration of the equation. Developed element is combined to pre-developed FEM code for THM phenomena in porous media. Numerical results of Thermal Response Test showed that line-source model overestimates equivalent thermal conductivity of surrounding soils due to thermal interaction between adjacent pipes and finite length of the pipe. Thus, inverse analysis for the TRT simulation was conducted to present optimal transformation matrix with utmost convergence.

대변형 압밀방정식의 수식화

신호성,이승래 한국지반공학회 2013 한국지반공학회논문집 Vol.29 No.6

Embankments on soft ground experience significant deformation during time-dependent consolidation settlement, as well as an initial undrained settlement. Since infinitesimal strain theory assumes no configuration change and minute strain during deformation, finite strain analysis is required for better prediction of geotechnical problems involving large strain and geometric change induced by imposed loadings. Updated Lagrangian formulation is developed for time-dependent consolidation combining both force equilibrium and mass conservation of fluid, and mechanical constitutive equation is written in Janumann stress rate. Numerical convergence during Newton’s iteration in large deformation analysis is improved by Nagtegaal’s approach of considering the effect of rotation in mechanical constitutive relationship. Numerical simulations are conducted to discuss numerical reliability and applicability of developed numerical code: deformation of cantilever beam, two-dimensional consolidation. The numerical results show that developed formulation can efficiently describe large deformation problems. Proposed formulation is expected to facilitate the upgrading of a numerical code based on infinitesimal strain theory to that based on finite strain analysis.

EuroQol-5 Dimension 건강가중치를 이용한 한국인의 건강수준의 형평성 측정

신호성,김동진,Shin, Ho-Sung,Kim, Dong-Jin 대한예방의학회 2008 예방의학회지 Vol.41 No.3

Objectives : Despite various government initiatives, including the expansion of national health insurance coverage, health inequality has been a key health policy issue in South Korea during the past decade. This study describes and compares the extent of the total health inequality and the income-related health inequality over time among Korean adults. Methods : This study employs the 1998, 2001 and 2005 Korean National Health and Nutrition Examination Surveys (KNHANESs). The self-assessed health (SAH) ordinal responses, measured on a five-point scale, resealed to cardinal values to measure the health inequalities with using interval regression. The boundaries of each threshold for the interval regression analysis were obtained from the empirical distribution of the EuroQol-5 Dimension (EQ-5D) valuation weights estimated from the 2005 KNHANES. The final model predicting the individuals' health status included age, gender, educational attainment, occupation, income, and the regional prosperity index. The concentration index was used to measure and analyze the health inequality. Results : The KNHANES data showed an unequal distribution of the total health inequality in favor of the higher income groups, and this is getting worse over time (0.0327 in 1998, 0.0393 in 2001 and 0.0924 in 2005). The income-related health inequality in 2005 was 0.0278, indicating that 30.1% of the total health inequality can be attributed to income. Conclusions : The findings indicate there are health inequalities across the sociodemographic and income groups despite the recent government's efforts. Further research is warranted to investigate what potential policy actions are necessary to decrease the health inequality in Korea.

의료이용의 지역적 불평등: 지역단위 접근의 중요성

신호성 한국보건사회연구원 2012 보건·복지 Issue&Focus Vol.145 No.-

대변형을 고려한 연약지반 압밀해석

신호성,김윤태,김주용,이승래 대한토목학회 1996 대한토목학회 학술발표회 논문집 Vol.1996 No.3

고객자산의 속성이 서비스 고객 열의 행동에 미치는 영향

신호성,유재원 한국유통학회 2015 한국유통학회 학술대회 발표논문집 Vol.2015 No.2

지반내 자연대류에 대한 수치해석적 논의

신호성 한국지반공학회 2017 한국지반공학회논문집 Vol.33 No.2

Thermal behavior of soils is mainly focused on thermal conduction, and the study of natural convection is very limited. Increase of soil temperature causes natural convection due to buoyancy from density change of pore water. The limitationsof the analysis using fluid dynamics for natural convection in the porous media is discussed and a new numerical analysisis presented for natural convection in porous media using THM governing equations fully coupled in the macroscopicview. Numerical experiments for thermal probe show increase in the uncertainty of thermal conductivity estimated withoutconsidering natural convection, and suggest appropriate experimental procedures to minimize errors between analyticalmodel and numerical results. Burial of submarine power cable should not exceed the temperature changes of 2°C atthe depth of 0.2 m under the seabed, but numerical analysis for high permeable ground exceeds this criterion. Temperatureand THM properties of the seafloor are important design factors for the burial of power cable, and in this case effectsof natural convection should be considered. Especially, in the presence of heat sources in soils with high permeability,natural convection due to the variation of density of pore water should be considered as an important heat transfermechanism.

모듈러 도로시스템의 동결-융해에 대한 수치해석적 연구

신호성,김진욱,이장근,김동규 한국지반공학회 2017 한국지반공학회논문집 Vol.33 No.3

In order to understand response of geo-structures to the freezing-thawing process in the ground, it is necessary toconsider phase change of the pore water of the ground and also to understand soil interaction with structures. In thisstudy, numerical analysis was carried out for freezing and thawing effect on the modular road system. Neumann’stheoretical equation for freezing-thawing processes in porous media can be used to estimate frozen depth and heavingfrom basic soil properties and ground and surface temperature, but its application is limited to the case for the sedimentwith fully saturated condition and zero unfrozen water content. Numerical analysis of the modular road system wasperformed on various soil types and different ground water table as the varying freezing index. The amount of heavingin the silty soil was much larger than those in granite weathered soil or sandy soil, and lowering groundwater levelreduced ground heaving induced by freezing. Numerical analysis for temperature history of the ground surface predictedresidual heaving near the surface by the freeze-thaw process in silty soil. It ought to reduce stiffness and bearing capacityof the ground so that it will impair stability and serviceability of new road system. However, the amount of residualheaving was insignificant for the road system installed in weathered soil granite and sandy soil. Since modular roadsystem is a pavement structure mounted on the supporting substructure unlike the prevalent road pavement system, strictcriteria should be applied for uniform and differential settlement of the pavement system.