• 보건의료산업학회지
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• 제6권3호
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• pp.117-125
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• 2012

The purpose of this study was to investigate current status of 19 general hospitals which performed the hospital social responsibility (HSR) to global health issues. The survey focused on the global healthcare supporting system & activity (including the administration, information, materials, finance, and human resources, et al.), and the government's policy in Korea. Based on the analysis of survey data, the main global health issues of general hospitals were activities of overseas volunteers (56%) and aids of the developing countries (19%). Also, general hospitals have mainly supported into eastern Asia (49%). And then, the most important goal of general hospitals related these activities kept the founding principle of a hospital for global health issues (53%). The second ranking was the social responsibility (32%) and the interchange between Korean and foreign hospitals (32%). There were many differences between general hospitals about the global healthcare supporting system & activities for HSR to global health issues. In conclusion, we suggest that most of general hospitals in Korea would be gotten prior setting the global issues for unmet-need of the developing countries around the world in the near future. This study also served as the effective way by partnership on global health issues of general hospitals for recognizing the HSR as hospital governance.

• Smart Structures and Systems
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• 제26권2호
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• pp.227-239
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• 2020

Despite proven effectiveness and accuracy in laboratories, the existing damage assessment based on guided ultrasonic waves (GUWs) or acoustic emission (AE) confronts challenges when extended to real-world structural health monitoring (SHM) for railway tracks. Central to the concerns are the extremely complex signal appearance due to highly dispersive and multimodal wave features, restriction on transducer installations, and severe contaminations of ambient noise. It remains a critical yet unsolved problem along with recent attempts to implement SHM in bourgeoning high-speed railway (HSR). By leveraging authors' continued endeavours, an SHM framework, based on actively generated diffuse ultrasonic waves (DUWs) and a benchmark-free condition contrast algorithm, has been developed and deployed via an all-in-one SHM system. Miniaturized lead zirconate titanate (PZT) wafers are utilized to generate and acquire DUWs in long-range railway tracks. Fatigue cracks in the tracks show unique contact behaviours under different conditions of external loads and further disturb DUW propagation. By contrast DUW propagation traits, fatigue cracks in railway tracks can be characterised quantitatively and the holistic health status of the tracks can be evaluated in a real-time manner. Compared with GUW- or AE-based methods, the DUW-driven inspection philosophy exhibits immunity to ambient noise and measurement uncertainty, less dependence on baseline signals, use of significantly reduced number of transducers, and high robustness in atrocious engineering conditions. Conformance tests are performed on HSR tracks, in which the evolution of fatigue damage is monitored continuously and quantitatively, demonstrating effectiveness, adaptability, reliability and robustness of DUW-driven SHM towards HSR applications.

• 한국소음진동공학회논문집
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• 제22권11호
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• pp.1078-1088
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• 2012

Recently, the vibration and structure-borne noise induced by passing trains are of great concerns, and the floating slab track is highlighted as one of most efficient alternatives to reduce the railway vibration. However, due to the non-linearity and viscosity of rubber spring used in the floating slab track, its dynamic behavior is very complex. In this study, therefore, to simulate the dynamic behavior of floating slab track with a better accuracy, a nonlinear viscoelastic rubber spring model that can be incorporated in commercial finite element analysis codes has been proposed. This model is composed of a combination of elastic spring element, friction element and viscous element, and termed the "generalized friction viscoelastic model(GFVM)". Also, in this study, the method to determine the model parameters of GFVM based on Berg's 5-parameter model was presented. The results of the finite element analysis with this rubber spring model exhibit very good correlation with the test results of a laboratory mock-up test, and the feasibility of GFVM has been verified.

• 한국철도학회논문집
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• 제10권5호
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• pp.499-505
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• 2007

본 연구의 주목적은 고속선 콘크리트 슬래브 궤도시스템에서 레일패드의 피로효과에 따른 영향을 분석하는 데에 있다. 이에 3차원 해석모델 및 실내시험을 통해 도출된 레일패드의 피로효과(경화, 스프링계수 증가)가 고속선 궤도의 역학적 거동에 미치는 영향을 분석하였다. 본 연구에서는 콘크리트 슬래브 궤도의 적정 탄성력 확보여부를 의미하는 레일패드의 적정스프링계수 산정에 관한 연구의 일환으로 고속철도 콘크리트 슬래브 궤도에 적용된 레일체결시스템에 대한 실내시험을 통한 레일패드의 정적스프링계수를 산정하고 체결시스템에 대한 피로시험을 통해 도출된 피로효과가 고려된 레일패드의 스프링계수 변화를 해석모델에 적용함으로써 향후 고속선 콘크리트 슬래브 궤도운영에서의 열차 주행안정성 확보 및 합리적인 궤도유지관리를 위한 기초데이터를 확보하고자 한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 춘계학술대회 논문집
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• pp.528-534
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• 2006

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 2000년도 제52차 추계학술대회 연제집
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• pp.181-182
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• 2000

• 한국철도학회논문집
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• 제15권6호
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• pp.662-669
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• 2012

2004년에 세계에서 5번째로 한국에서 고속철도를 운영하게 되었으며, 2011년 서울~부산간 전구간의 철도건설이 완공되어 고속철도가 운행되고 있다. 경부고속철도와 같은 대형국책사업에 있어 계획된 공기에 영향을 미치는 요소는 다양하였다. 국내에서는 처음으로 시행된 고속철도 건설사업으로서 본 사업과정상에 잦은 국가정책의 변경, 설계 및 시공상 사업관리의 어려움, 환경단체나 지역주민 등 이해관계자와의 갈등 등이 철도건설공기에 영향을 주는 주요 요소로 볼 수 있으며 경부고속철도를 통해 경험한 지연요소에 대한 종류, 문제점 등을 분석하여 향후 대형국책사업 등의 시행에 있어서 사업관리 및 추진의 효율성 향상에 기여하고자 한다. 특히, 사업단계에서부터 철저한 공기관리가 필요하며, 아울러 최근 중요시되는 환경문제 등에 관해서는 사업전반에 걸쳐 관리가 필요한 것으로 나타났다.

• 센서학회지
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• 제16권1호
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• pp.68-76
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• 2007

In general, the braking system of a high speed train has an important role for the safety of the train. To stop safely the train at its pre-decided position, it is necessary to properly combine the various brakes. The train has adopted a combined electrical and mechanical (friction) braking systems. In order to design a good brake system, it is essential for designers to predict the brake performance. In this paper, the braking performance analysis program has been developed and verified by comparing the simulation results with the brake test results of HSR-350x; both results match very well. Also, the brake performances of high speed trains can be predicted by using this program under various conditions.

• 한국철도학회논문집
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• 제10권2호
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• pp.137-145
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• 2007

In traditional financial theory, the discount cash flow model(DCF or NPV) operates as the basic framework for most analyses. In doing valuation analysis, the conventional view is that the net present value(NPV) of a project is the measure of the present value of expected net cash flows. Thus, investing in a positive(negative) NPV project will increase(decrease) firm value. Recently, this framework has come under some fire for failing to consider the options of the managerial flexibilities. Real option valuation(ROV) considers the managerial flexibility to make ongoing decisions regarding the implementation of investment projects and the deployment of real assets. The appeal of the framework is natural given the high degree of uncertainty that firms face in their technology investment decisions. This paper suggests an algorithm for estimating volatility of logarithmic cash flow returns of real assets based on the Black-Sholes option pricing model, the binomial option pricing model, and the Monte Carlo simulation. This paper uses those models to obtain point estimates of real option value with the G7- HSR350X(high-speed train).

• 한국철도학회논문집
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• 제8권5호
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• pp.398-404
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• 2005

In this paper, we introduce the on-line test of the current collection characteristics for HSR 350x(Korea High Speed Train project) that have been performed in the Kyoung-bu high-speed line since 2002. Through the analysis of measured data during on-line test, the variation trend of contact force between pantograph and contact wire of catenary according to the span type, the track conditions and driving patterns is reviewed. In order to analyze the variation trend of contact force, we have checked the span type of catenary in KP 24 - 125 out of Kyoung-bu high speed line and obtained the statistical processing result per each span type. This study shows that the track conditions do not affect on the dynamic performance between pantograph and contact wire catenary, and the span type and the driving pattern are important factors in determining the good interaction between them.