• Title/Summary/Keyword: Conceptual change

Search Result 525, Processing Time 0.023 seconds

A Fundamental Study on Offshore Structures of high pressure control valve (해양구조물용 고압 컨트롤 밸브에 대한 기초 연구)

  • Lee, Chi-Woo;Jang, Sung-Cheol
    • Journal of the Korean Society of Manufacturing Technology Engineers
    • /
    • v.19 no.6
    • /
    • pp.883-888
    • /
    • 2010
  • This study have goal with conceptual design for Offshore Structures of high pressure control valve for localization. Ball valve for development accomplished with flow analysis based on provision of ANSI B16.34, ANSI B16.10, ANSI B16.25 In order to localize the Offshore Structures high pressure control valve. Numerical simulation using CFD (Computational Fluid Dynamic) in order to predict a mass flow rate and a flow coefficient form flow dynamic point of view. The working fluid assumed the glycerin (C3H8O3). The valve inlet and outlet setup a pressure boundary condition. The outlet pressure was fixed by atmospheric pressure and calculated until increasing 1bar to 10bar. CFD analysis used STAR-CCM+ which is commercial code and Governing equations were calculated by moving mesh which is rotated 90 degrees when ball valve operated opening and closing in 1 degree interval. The result shows change of mass flow rate according to opening and closing angle of valve, Flow decrease observed open valve that equal percentage flow paten which is general inclination of ball valve. Relation with flow and flow coefficient can not be proportional according to inlet pressure when compare with mass flow rate. Because flow coefficient have influence in flow and pressure difference. Namely, flow can be change even if it has same Cv value. The structural analysis used ANSYS which is a commercial code. Stress analysis result of internal pressure in valve showed lower than yield strength. This is expect to need more detail design and verification for stem and seat structure.

Improvement of Service Tree Analysis Using Service Importance (서비스 중요도를 사용한 서비스나무분석의 개선)

  • Park, Jong Hun;Hwang, Young Hun;Lee, Sang Cheon
    • Journal of Korean Society of Industrial and Systems Engineering
    • /
    • v.40 no.2
    • /
    • pp.41-50
    • /
    • 2017
  • The purpose of this paper is to improve the service tree analysis introduced recently by Geum et al. [15]. Service tree analysis structures the service based on the customer participation perspective and provides a qualitative analysis method categorizing the service elements on the basis of its impact to top service. This paper attempts to apply the concept of reliability importance to the service tree analysis as a perspective of quantitative analysis, which is considered little in Geum et al. [15]. Reliability importance is a measure of the structural impact of the components that make up the system on the system lifetime in reliability engineering field and often used in fault tree analysis. We transform the reliability importance into service importance in accordance with service tree analysis, so that the influence of service elements on the service can be judged and compared. The service importance is defined as the amount of change of the service according to the change of the service element, therefore, it can be utilized as an index for determining a service element for service improvement. In addition, as an index for paired service elements, the relationship between the two service components can be measured by joint service importance. This paper introduces conceptual changes in the process of applying reliability importance to service analysis, and shows how to use the service importance for identifying the priority of service element for the final service and improving customer satisfaction through an example. By using the service importance and joint service importance in service tree analysis, it is possible to make efficient decision making in the process of determining the service elements for analyzing and improving the service.

A Numerical Analysis on High Pressure Control Valve for Offshore (해양구조물용 고압 컨트롤 밸브 수치해석)

  • Yi, Chung-Seub;Jang, Sung-Cheol;Jeong, Hwi-Won;Nam, Tae-Hee
    • Proceedings of the SAREK Conference
    • /
    • 2008.06a
    • /
    • pp.1195-1200
    • /
    • 2008
  • This study have goal with conceptual design for Offshore Structures of high pressure control valve for localization. Ball valve for development accomplished with flow analysis based on provision of ANSI B16.34, ANSI B16.10, ANSI B16.25 In order to localize the Offshore Structures high pressure control valve. Numerical simulation using CFD(Computational Fluid Dynamic) in order to predict a mass flow rate and a flow coefficient form flow dynamic point of view. The working fluid assumed the glycerin($C_3H_8O_3$). The valve inlet and outlet setup a pressure boundary condition. The outlet pressure was fixed by atmospheric pressure and calculated until increasing 1bar to 10bar. CFD analysis used STAR-CCM+ which is commercial code and Governing equations were calculated by moving mesh which is rotated 90 degrees when ball valve operated opening and closing in 1 degree interval. The result shows change of mass flow rate according to opening and closing angle of valve. Flow decrease observed open valve that equal percentage flow paten which is general inclination of ball valve. Relation with flow and flow coefficient can not be proportional according to inlet pressure when compare with mass flow rate. Because flow coefficient have influence in flow and pressure difference. Namely, flow can be change even if it has same Cv value. The structural analysis used ANSYS which is a commercial code. Stress analysis result of internal pressure in valve showed lower than yield strength. This is expect to need more detail design and verification for stem and seat structure.

  • PDF

Exploring Teaching Way Using GeoGebra Based on Pre-Service Secondary Teachers' Understanding-Realities for Taylor Series Convergence Conceptions (테일러급수 수렴에 대한 예비중등교사의 이해실태와 GeoGebra를 활용한 교수방안 탐색)

  • Kim, Jin Hwan
    • School Mathematics
    • /
    • v.16 no.2
    • /
    • pp.317-334
    • /
    • 2014
  • The purpose of this study is to grasp pre-service secondary teachers' understanding-realities for Taylor series convergence conceptions and to examine a teaching way using GeoGebra based on the understanding-realities. In this study, most pre-service teachers have abilities to calculate the Taylor series and radius of convergence, but they are vulnerable to conceptual problems which give meaning of the equality between a given function and its Taylor series at any point. Also they have some weakness in determining the change of radius of convergence according to the change of Taylor series' center. To improve their weakness, we explore a teaching way using dynamic and CAS functionality of GeoGebra. This study is expected to improve the pedagogical content knowledge of pre-service secondary mathematics teachers for infinite series treated in high school mathematics.

  • PDF

What is Shared in Collaborative Problem Solving Process of Scientific Gifted Students? (과학영재들은 협업적 문제해결과정에서 무엇을 공유하는가?)

  • Lee, Ji Won;Kim, Jung Bog
    • Journal of Gifted/Talented Education
    • /
    • v.23 no.6
    • /
    • pp.1099-1115
    • /
    • 2013
  • Collective intelligence has been focused because it plays an important role for creating knowledge. In order to solve a problem with collective intelligence, collaborative works sharing information are required. In this study, we have investigated what informations are shared while 4 science gifted students are asked for scientific explanation to the problem which is cognitive conflict. They have shared presupposition and problem in stage of problem finding, aims and means of problem solving in stage of setting up hypotheses, and constraints for evaluation and results of evaluation in stage of hypotheses evaluation. Our research tells that group can create knowledge through sharing information and make a change of their concepts. Our foundation of these spontaneous conceptual change gives an implication for gifted education.

Changes in Public Health Perceptios after the Outbreak of Coronavirus Disease-19 among the Gangwon Province Residents Focusing on the Results of the Gangwon Province Residents' Panel Survey 2019-2020 (코로나바이러스감염증-19 전후 강원도민의 공공의료 인식 비교 : 2019-2020 강원도민 보건의료패널조사 결과를 중심으로)

  • Yu Seong Hwang;Heui Sug Jo;Su Mi Jung
    • Journal of agricultural medicine and community health
    • /
    • v.48 no.1
    • /
    • pp.13-27
    • /
    • 2023
  • Objectives: The purpose of this study is to investigate changes in public health-related perceptions of residents of Gangwon province after the outbreak of Coronavirus disease-19(COVID-19) of the public. Methods: We performed paired T-test analysis to measure the change in public health-related perceptions before and after COVID-19. We also utilized generalized estimating equations to identify demographic factors correlated with public health-related perceptions. Results: The public perceived public health as 'All citizens can use medical care and protect/promote health.' The concept was the most popular, from 94.3% in 2019 to 95.5% in 2020. In addition, after COVID-19, residents of Gangwon province's satisfaction with medical services increased, but the overall level was not high. Among the eight essential healthcare needs after COVID-19, cardiovascular disease and injury services have emerged as preferred services. However, by sociodemographic factors, distinctive responses were detected. Conclusions: Through COVID-19, Gangwon residents' awareness of the public's health rights has increased. Those living in vulnerable areas or with unmet medical care, supported strengthening public health care. In addition, although medical satisfaction has increased, it is not satisfied, so listening to the voices of the population group with low satisfaction is essential. Lastly, since the necessity of essential health care may change due to specific events, the local government needs to plan health projects reflecting the needs of residents. Therefore, when designing the public health care strategy in Gangwon province, the local government should consider not only political factors but also environmental factors, demographic and conceptual factors.

Yongdoseo(龍圖墅) and Guimunwon(龜文園) which Applied a Sangsu(象數) Principle on Garden Composition (상수(象數) 원리를 정원구성에 적용한 용도서(龍圖墅)와 귀문원(龜文園))

  • Hong, Hyoung-Soon
    • Journal of the Korean Institute of Traditional Landscape Architecture
    • /
    • v.30 no.2
    • /
    • pp.119-129
    • /
    • 2012
  • Yongdoseo and Guimunwon are described in "Bokgeo(卜居, fixabode)" of "Sanlimkyengje(山林經濟)" written by Manseon Hong. This record is a unique garden conceptual idea applying the principles of Hetu(河圖) and Luoshu(洛書), fanciful gardens which have not been actually constructed. Here, two garden types were concretely described respectively, however the underlying meaning therein cannot be apprehended without exact understanding about Sangsu studies. Therefore, the purpose of this study is to illuminate the meaning contained in Garden illustration and the historical meaning of landscape therein through considering this text. To achieve the purpose of this study, the writer and the compiler who are the background of this writing and the outline of Sangsu studies were investigated. Also, the principles of Saengsu(生數), Seongsu(成數), Yin Yang(陰陽), Four Bodies(四象), Palgwedo(八卦圖), etc. which are in Hetu and Luoshu were considered. The result of this study went through this research process is summarized as follows. First, Hetu Luoshu are conceptual definitions which wholly abstracted the basic propositions of Sangsu philosophy such as the universe change principle, etc., while Yongdoseo and Guimunwon can be said to be operational definitions which apply those as garden composition principle, enabling to experience the meaning contained therein concretely and explain it in a replicable way. This attempt is a unique example, unprecedented in Chinaas well. Second, as a livingspace, garden was selected as a means to concretize operational definitions about the meaning of Hetu Luoshu, and as the property to reproduce the bearings concept, the location and the number, etc. of Hetu Luoshu, Taegukjeong(太極亭), Shipjagak(十字閣), Dondae(墩臺), well, pond as well as various kinds of trees were used. Third, the main motif of Yongdoseo and Guimunwon is the relation between Apriority(先天) and Posterior(後天), and the relation between Constitution(體) and Use(用) of Hetu and Luoshu respectively. That is, Yongdoseo planted evergreen trees such as Shipjangcheong(十長靑) in order to symbolize the universe creation principle which Hetu stands for, i.e. silent, harmonious, orderly and win-win image. In Guimunwon, flowering trees(花木) and fruit trees(果木) were planted freely to express the change of Posterior which Luoshu stands for, thatis, dynamic, disharmonious, disorderly, incompatible(相剋) and changing image. The effects intended to be attained through such planting were, 'freshness and cheerfulness(淸爽)' of Yongdoseo and 'splendidness' of Guimunwon respectively. Sangsu studies based on Hetu and Luoshu is a unique thinking system to the Orient which came from the accumulated wisdom of several scholars from various schools through a long period since ancient times. Therefore, the concept and the theory thereof are profound and huge, and its viewpoints of interpretation are diverse. It is a limit of this study that more in-depth and various consideration was not performed. As a further research project, more empirical study of Orientalism such as Sangsu studies, etc. inherent in Traditional Garden is necessary.

A Study on the Characteristics of Flexibility in Interior Architectural Composition -focused on Mathematical Arrangement Organization- (실내공간구성의 가변적 표현특성에 관한 연구 -수학적 배열원리를 중심으로-)

  • 이주현;신홍경
    • Korean Institute of Interior Design Journal
    • /
    • no.21
    • /
    • pp.10-16
    • /
    • 1999
  • Mathematics is considered to the beginning of designing thinking because of the sense of logical order system. In this study, it was regarded the mathematics as the logic and the measurement of design system. as is often the case in history, mathematics, it is regard as conceptual model of architectural though, as aesthetic proportional measure and the mirror of thought. The direction of this study is rather multi-sided approaching to the spatial concept than one-sided plane. It is multi-acceptable way to apply mathematical principle to the pace and to be a flexible one. And boundary of interpretation of the flexibility means potential use-ability, and the strictly meaning of flexibility means that the acception of the various Secession and the Change of space. And the various interpretation of the flexibility only can expressed in the relation of opposite concept: the assembly and the disassembly, the expand and the decease, the open and the close and the construct and the de-construct. Mathematics provide the resonable way in architectural thinking and endow the order as logical organizatiov. Regarding these facts, this research is for making it possible to consider the expression property of interior space combination as the way of understanding the accepting of the changes of the times with the mathematical induction, using the rational method like the mathematical arrangement organizatiov.

  • PDF

Identification of Potential Environmental Impacts among Renewable Energy Technologies Promising to Minimize Global Warming (지구온난화 최소화를 위한 신재생 에너지들의 잠재환경영향)

  • Kim, Yong-Bum;Chung, Yong
    • Journal of Environmental Impact Assessment
    • /
    • v.17 no.1
    • /
    • pp.67-79
    • /
    • 2008
  • Global warming, which is one of the most serious challenges, has been the subject of intense debate and concern for many scientists, policy-makers, and citizens for at least the past decade. To protect the health and economic well-being of current and future generations, we must reduce our emissions like carbon dioxide. Alternatives to achieve an energy future without serious global warming are to change to clean and renewable sources of energy like the wind, the sun lights, rivers, the biomass, hydrogen, and oceans. To identify some of the key and new environmental impacts associated with renewable energy and hydrogen energy, we set up the new conceptual methodology. Specifically, new identified environmental and health impacts are related with the usage of hydrogen energy. When comparing with fossil fuel, the renewable energies can reduce the release of carbon dioxide when they are used except hydrogen produced from fossil fuel. However, all renewable energy technologies are not appropriate to all applications or locations. Our results suggest that all of alternatives to replace fossil fuel can release the several global and local impacts although they seems to be smaller than the impacts from fossil fuel. Therefore, the quantitative and detail analysis to assess environmental impacts of the alternative energies might be useful to make our decision for the future energy against the global warming.

Estimation of Resistance of Smart Harbor Crane Ship (Smart Harbor Crane Ship의 저항 추정)

  • Shin, Hyun-Kyoung;Kim, Min-Su;Jeong, Won-Jin;Ha, Yong-Hwak
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.49 no.1
    • /
    • pp.1-5
    • /
    • 2012
  • Recently, with increasing container ships' volume continuously, the conceptual design "Smart Harbor" of newly logistics processing system has been suggested. It is necessary to estimate resistance and horsepower for the selection of an appropriate propulsor at the initial design stage of Smart Harbor. In this study, CFD and the circulating water channel of the University of Ulsan are employed for estimating the resistance of the Smart Harbor Crane Ship with 1/100 scaled model. Two turbulent models are used. One is realizable k-${\varepsilon}$and the other is Reynolds stress turbulence model. In addition, the effects of the change in y+ and the number of meshes are considered during analysing.