• Title, Summary, Keyword: Analysis

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Spatial Analysis Methods for Asbestos Exposure Research (석면노출연구를 위한 공간분석기법)

  • Kim, Ju-Young;Kang, Dong-Mug
    • Journal of Environmental Health Sciences
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    • v.38 no.5
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    • pp.369-379
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    • 2012
  • Objectives: Spatial analysis is useful for understanding complicated causal relationships. This paper focuses trends and appling methods for spatial analysis associated with environmental asbestos exposure. Methods: Literature review and reflection of experience of authors were conducted to know academic background of spatial analysis, appling methods on epidemiology and asbestos exposure. Results: Spatial analysis based on spatial autocorrelation provides a variety of methods through which to conduct mapping, cluster analysis, diffusion, interpolation, and identification. Cause of disease occurrence can be investigated through spatial analysis. Appropriate methods can be applied according to contagiousness and continuity. Spatial analysis for asbestos exposure source is needed to study asbestos related diseases. Although a great amount of research has used spatial analysis to study exposure assessment and distribution of disease occurrence, these studies tend to focus on the construction of a thematic map without different forms of analysis. Recently, spatial analysis has been advanced by merging with web tools, mobile computing, statistical packages, social network analysis, and big data. Conclusions: Because the trend in spatial analysis has evolved from simple marking into a variety of forms of analyses, environmental researchers including asbestos exposure study are required to be aware of recent trends.

Survival analysis: part II - applied clinical data analysis

  • In, Junyong;Lee, Dong Kyu
    • Korean Journal of Anesthesiology
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    • v.72 no.5
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    • pp.441-457
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    • 2019
  • As a follow-up to a previous article, this review provides several in-depth concepts regarding a survival analysis. Also, several codes for specific survival analysis are listed to enhance the understanding of such an analysis and to provide an applicable survival analysis method. A proportional hazard assumption is an important concept in survival analysis. Validation of this assumption is crucial for survival analysis. For this purpose, a graphical analysis method and a goodnessof-fit test are introduced along with detailed codes and examples. In the case of a violated proportional hazard assumption, the extended models of a Cox regression are required. Simplified concepts of a stratified Cox proportional hazard model and time-dependent Cox regression are also described. The source code for an actual analysis using an available statistical package with a detailed interpretation of the results can enable the realization of survival analysis with personal data. To enhance the statistical power of survival analysis, an evaluation of the basic assumptions and the interaction between variables and time is important. In doing so, survival analysis can provide reliable scientific results with a high level of confidence.

윈도우즈 GUI 환경을 이용한 모터내장형 고속주축계의 정특성/동특성 해석시스템 개발

  • 이용희;김석일;이재윤
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.836-840
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    • 1995
  • Recently, the motor-integrated spindle spindle systems have been used to simplify the machine tool structure, to improve the motion flexibility of machine tool, and to perform the high-speed machining. In this study, a static and dynamic analysis system for motor-integrated high-speed spindle systems is developed based on Timoshenko theory, finite element method and windows programming techniques. Since the system has various analysis modules related to static deformation analysis, modal analysis, frequency response analysis, unbalance response analysis and so on, it is useful in performing systematically the design and evaluation processes of motor-integrated high-speed spindle systems under windows GUI encironment.

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Study on the durability assessment based on CAE analysis (CAE 해석 기반 내구도 평가 방법에 대한 연구)

  • 주병현;남기원;이병채
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.844-848
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    • 2004
  • We evaluate the durability of vehicle chassis component under dynamic loadings. Since the fatigue analysis of vehicle component is based on the dynamic load history it must be done by dynamic analysis. But in case the vehicle component has natural frequencies much larger than reversing frequencies of load history, we can get small analysis errors by applying quasi-static analysis. So it is inefficient that we apply to the dynamic analysis for all the vehicle components. In this research, we discuss the quasi-static analysis method which is appropriate for the fatigue analysis. And in case we can only perform the fatigue analysis based on dynamic analysis, we introduce more efficient method in the analysis time and hard disk storage.

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Thickness Effect on the Structural Durability of a Bileaflet Mechanical Heart Valve

  • Kwon, Young-Joo
    • International Journal of Precision Engineering and Manufacturing
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    • v.4 no.4
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    • pp.5-12
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    • 2003
  • This paper discusses about the thickness effects on the structural durability of a bileaflet mechanical heart valve (MHV). In the study on the design and the mechanical characteristics of a bileaflet mechanical heart valve, the fluid mechanics analysis on the blood flow passing through leaflets, the kinetodynamics analysis on the rigid body motion of the leaflet induced by the pulsatile blood flow, and the structural mechanics analysis for the deformed leaflet are required sequentially and simultaneously. Fluid forces computed in the fluid mechanics analysis on the blood flow are used in the kinetodynamics analysis for the leaflet motion. Thereafter, the structural mechanics analysis for the deformed leaflet follows to predict the structural strength variation of the leaflet as the leaflet thickness changes. Analysis results show that structural deformations and stresses increase as the fluid pressure increases and the leaflet thickness decreases. Analysis results also show that the leaflet becomes structurally weaker and weaker as the leaflet becomes thinner and thinner.

Secondary Analysis: Focusing on Qualitative Research (이차분석 : 질적연구를 중심으로)

  • 이명선
    • Journal of Korean Academy of Nursing
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    • v.34 no.1
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    • pp.35-44
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    • 2004
  • Purpose: This article explored issues arising from secondary analysis of qualitative data and analyzed the results of qualitative secondary analysis studies published in English, focusing on the methodological aspects. Method: A total of 29 studies were identified as qualitative secondary analysis studies, retrieving from the CINAHL database from 1982 to 3rd week of April 2003. These studies were analyzed by publication year, research method, and type of approach to secondary analysis. Result: The year that the qualitative secondary analysis study first published was 1992 and the number of the studies using secondary analysis has increased after the middle of 1990s. Grounded theory was the one the most frequently used(n=11, 37.9%) and phenomenological study the second most(n=6, 20.7%). In terms of types of approach, fifteen studies(51.7%) focused on the specific concepts that were not explored in the primary studies. Nine(31.0%) focused on the specific types of participants. Six were aimed to integrate contexts or perspectives to generate more general and abstract analysis of qualitative data. Conclusion: The results of this article will stimulate methodological discussion of qualitative secondary analysis and activate qualitative studies using secondary analysis.

Characteristic Analysis of IPMSM for Electric Vehicle Propulsion With Variable Operating Condition Based on Numerical Analysis (운전조건을 고려한 전기자동차 구동용 IPMSM의 수치해석 기반의 제 특성 해석)

  • Im, Chae-Young;Jung, Sang-Yong;Lee, Cheol-Gyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.8
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    • pp.1502-1509
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    • 2011
  • This Paper presents characteristic analysis in terms of interior permanent magnet synchronous motor for electric vehicle propulsion using numerical analysis. Torque ripple analysis, thermal analysis, demagnetization analysis of permanent magnet and mechanical stress analysis with variable operating condition are presented. According to these characteristic analysis, both the performance of motor and possible problems during the operation are examined thoroughly in advance.

Sensitivity-based reliability analysis of earth slopes using finite element method

  • Ji, Jian;Liao, Hong-Jian
    • Geomechanics and Engineering
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    • v.6 no.6
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    • pp.545-560
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    • 2014
  • For slope stability analysis, an alternative to the classical limit equilibrium method (LEM) of slices is the shear strength reduction method (SRM), which can be integrated into finite element analysis or finite difference analysis. Recently, probabilistic analysis of earth slopes has been very attractive because it is capable to take the soil uncertainty into account. However, the SRM is less commonly extended to probabilistic framework compared to a variety of probabilistic LEM analysis of earth slopes. To overcome some limitations that hinder the development of probabilistic SRM stability analysis, a new procedure based on recursive algorithm FORM with sensitivity analysis in the space of original variables is proposed. It can be used to deal with correlated non-normal variables subjected to implicit limit state surface. Using the proposed approach, a probabilistic finite element analysis of the stability of an existing earth dam is carried out in this paper.

Seismic Analysis of LNG Storage Tank (LNG 저장탱크의 내진 해석)

  • Lee, Seung-Pyo;Ha, Sung-Kyu;Koh, Byung-Kab
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.5
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    • pp.1095-1101
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    • 2008
  • In this paper, seismic analysis of LNG storage tank is performed. The analysis models are both pipe and pipe, wall and guide of LNG tank. And equivalent static analysis and response spectrum analysis are applied to these two models, respectively. From the analysis, deflections and equivalent stresses are compared. Results show that response spectrum analysis is more accurate than equivalent static analysis for LNG storage tank.

Types and Patterns of the Analysis of Technology and Market (기술시장분석의 유형과 패턴)

  • Seol, Sung-Soo;Park, Jung-Min
    • Journal of Korea Technology Innovation Society
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    • v.7 no.1
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    • pp.182-206
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    • 2004
  • This is the review of 2,500 cases on the trend analysis of technology and market. We find the fact that the patterns of trend analysis are defined by the purpose and size of the series and analysis, not by the difference of experience, educational background, country or organization. Based on these facts, we define 14 types of the analysis of technology and market. Also we conceptualize several patterns of the analysis in methodology, techniques, analytical index, structure, information source and the value by types of trend analysis.

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