• Title/Summary/Keyword: Precondition

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A Case Study of Placed Remicon in "S" Apartment (현장 콘크리트의 품질에 관한 소고)

  • 이학영;윤두순
    • Journal of the Korean Professional Engineers Association
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    • v.30 no.6
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    • pp.113-120
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    • 1997
  • This subject,'S" apartment structural frame has not been achieved without considerable effort by all quality controller involved. Therefore, it is appropriate at this time to report by all the fact of concrete quality control in our site. These are emphasized that the average strength of placed concrete must always exceed the specified value of design strength used in the structural design phase. In general, quality of ready mixed concrete largely depends not only upon the manner of production and proper observance of recognized methods of placement, finishing, curing, transportation etc. ,but also many kinds of influential factors even more handling of the test procedure, As this practical report, approaching to judgement by analysis of sampled specimens in site weather placed concrete have satisfied quality compare the specified strength with the target strength which is applied to standard deviation related with influential factors as above mentioned. This case study is consist of 1) A foreword, 2) Site brief, 3) A precondition for analysis, 4) A formulas derivation and quality analysis, 5) Economic gains by the coefRcient of increase and 6) A conclusion.sion.

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Unsteady Modeling of a Solid Rocket Motor with a Composite Propellant (혼합형 고체추진제를 이용한 로켓의 비정상 성능해석)

  • Lee, Sung-Nam;Baek, Seung-Wook;Kim, Kyung-Moo;Kim, Yoon-Gon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.05a
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    • pp.175-178
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    • 2008
  • A Numerical Simulation which uses preconditioning algorithm to examine unsteady combustion processes for the AP/HTPB propellant with a converging-diverging nozzle has been compared with experimental data for solid rocket motor. To analysis reacting flow of solid rocket motor, unsteady pressure, temperature contour was simulated by grid moving of propellant.

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Numerical Investigation of the Stability of Flows induced by a Surface Acoustic Wave along a Slab

  • Chu W. Kwang-Hua
    • 한국전산유체공학회:학술대회논문집
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    • 2003.10a
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    • pp.77-79
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    • 2003
  • The stability of flows induced by a surface acoustic wave (SAW) propagating along the deformable walls in a confined parallel-plane microchannel or slab in the laminar flow regime is investigated. The governing equation which was derived by considering the nonlinear coupling between the deformable or waving interface and viscous fluids is linearized and then the problem is solved by a verified code based on the spectral method together with the associated interface and boundary conditions. The value of the critical Reynolds number was found to be near 1439 which is much smaller than the rigid-wall case: 5772 for conventional pressure-driven flows.

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Modeling of 2D/3D Solid Rocket Combustion Using Preconditioning Method (예조건 알고리즘을 적용시킨 고체로켓의 2D/3D 연소해석)

  • Lee, S.N.;Baek, S.W.
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.547-550
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    • 2008
  • A solid rocket motor has quite complex physical condition such exothermal chemical reaction in subsonic area and supersonic ex pansion in a converging-diverging nozzle. To introduce a simulation tool for compressible flow in supersonic range as well as incompressible chemical reaction zone in a whole rocket nozzle is a essential demand. Since the flow vary subsonic to super sonic, the convergence in computation becomes very low and unstable in a whole domain of rocket motor. This paper reports the 2-D Axisymmetric and simple 3-D solid propellant combustion and flow of gases in rocket motor by using a precondi tioning, shear stress turbulence modeling, AUSM(p). To simulate the simplified combustion process, Double base solid propellant is used to calculate reaction of solid propellant.

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Main Problems and Suggestions on Occupational Safety and Hygiene in Construction Sites (건설현장의 안전보건 주요 현안과 개선 방안)

  • Shim, Gyubeom
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.22 no.4
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    • pp.329-336
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    • 2012
  • Objectives: The aim of this study is to analyze main problems on occupational safety and hygiene in construction sites and to suggest some improvement methods. In order to decrease industrial accidents, I emphasize the approach paradigm shifts according to characteristics of construction workers. Methods: Pointing out the irrationality of current institutions by comparing bad outcomes of occupational safety and hygiene in construction industry and characteristics of construction workers. Results: In order to decrease industrial accidents, we need some approach paradigm shifts; the supply method of industrial safety and health fundamentals on the construction industry level, the accident rate calculation by using the actual construction workforce instead of an estimation, institutionalizing the prevention efforts themselves for industrial accidents, securing enough production costs for the precondition of occupational safety and hygiene in construction sites. Conclusions: I ascertain the need of the approach paradigm shifts for decreasing industrial accidents in the construction industry.

Prediction of Arc Welding Quality through Artificial Neural Network (신경망 알고리즘을 이용한 아크 용접부 품질 예측)

  • Cho, Jungho
    • Journal of Welding and Joining
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    • v.31 no.3
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    • pp.44-48
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    • 2013
  • Artificial neural network (ANN) model is applied to predict arc welding process window for automotive steel plate. Target weldment was various automotive steel plate combination with lap fillet joint. The accuracy of prediction was evaluated through comparison experimental result to ANN simulation. The effect of ANN variables on the accuracy is investigated such as number of hidden layers, perceptrons and transfer function type. A static back propagation model is established and tested. The result shows comparatively accurate predictability of the suggested ANN model. However, it restricts to use nonlinear transfer function instead of linear type and suggests only one single hidden layer rather than multiple ones to get better accuracy. In addition to this, obvious fact is affirmed again that the more perceptrons guarantee the better accuracy under the precondition that there are enough experimental database to train the neural network.

Constraints based Semantic Web Services Discovery for an Intelligent Agent (지능형 에이전트를 위한 제약조건 기반의 시맨틱 웹 서비스 검색)

  • Namgoong Hyun;Jung Seungwoo;Kim Hyung-il;Chung Moonyoung;Cho HyeonSung
    • Proceedings of the Korean Information Science Society Conference
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    • 2005.11b
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    • pp.505-507
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    • 2005
  • 시맨틱 웹 서비스 검색시스템은 제공자가 기술한 웹 서비스 시맨틱 기술을 웹 서비스 사용자의 요청에 의해 검색하여 사용자에게 반환한다. 이러한 검색은 의미적 비교를 통해 이루어지며, 의미적 비교는 OWL-S[4]와 같은 표준을 통해 기술된 웹 서비스의 입력과 출력, 조건, 효과(Input, Output, Precondition, Effect) 즉, IOPE 와 사용자의 요청의 그것에 대해 수행된다. 하지만, 이러한 검색은 때때로 웹 서비스를 이용하여 이용자에게 서비스를 제공하는 지능형 에이전트에게 적합하지 않다. 지능형 에이전트는 웹 서비스의 실행을 위한 입력의 변환과 반환된 출력의 선택을 통해 서비스를 이용 가능하므로 IOPE의 형식에 대한 정확한 일치를 요구하지 않는다. 본 논문에서는 지능형 에이전트에 보다 융통성 있는 검색 서비스의 제공을 위한 제약조건을 기반으로 시맨틱 웹 서비스 검색시스템에 대하여 설명한다.

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Motivational Factors for Persuasive System Adoption : Interactive Mirror System Case (설득적 시스템 사용 동기에 대한 연구 : 상호작용적 거울 시스템 중심으로)

  • Choi, Jeong-Youn;Kim, Gyeung-Min
    • Journal of Information Technology Applications and Management
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    • v.26 no.3
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    • pp.81-98
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    • 2019
  • Despite the growing enthusiasm for the persuasive system like an interactive mirror system little is known about what motivates the customers to try the system and makes customers return repeatedly to the system. The key to understanding persuasive system adoption is the identification of the preconditions needed for the system adoption. Using grounded theory building methodology, we identified the preconditions needed for the system adoption. First, past research regarding users' motivational factors to use the persuasive system is reviewed. Then, research methodology and data analysis are presented. Finally, the study findings and conclusions are presented.

Structure and Texture: A Note on Ransom′s Dualism (틀과 결: 랜섬의 이원론에 대한 고찰)

  • 봉준수
    • Lingua Humanitatis
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    • v.1 no.1
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    • pp.195-217
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    • 2001
  • According to John Crowe Ransom, "the poem is a loose logical structure with an irrelevant local texture." As is implied in the opposition between "structure" and "texture," Ransom′s is a dualistic, that is, non-organic, theory of poetry, in which the poem′s sound does not have any expressive function while its figurative language always goes beyond the realm of abstract meaning and celebrates the ontological density of the world. His theory relies heavily upon a series of oppositions-poetry and prose, art and science, concrete and universal, artistic and utilitarian, to name only a few-in order to uphold the humanistic value of poetry ("poetry as knowledge"). There is, however, a sense that his theoretical consistency derives from a determined refusal to see the blurry borderline between the oppositions. It is more or less easy to point out where Ransom′s theory falters, but more critical efforts should be made to probe into the personal and cultural significance of his persistent dualistic viewpoint. For Ransom the southerner, life demands the precarious balance between the oppositions as the very precondition for its existence and his dualism represents a way to understand man′s fallen state at the realistic level.

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Flow and Learning Emotions in Computer Education: An Empirical Survey

  • Wang, Chih-Chien;Wang, Kai-Li;Chen, Chien-Chang;Yang, Yann-Jy
    • Journal of Information Technology Applications and Management
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    • v.21 no.3
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    • pp.53-64
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    • 2014
  • It is important to keep learners' feeling positive during learning to enhance learning performance. According to flow theory,challenge-skill balance is a precondition for flow experience: Learners feel anxiety when the challenge of learning is higher than their ability, feel boredom when the challenge of learning is lower than learners' ability, and engage in flow status when the challenge of learning matches the learners' ability. However, the current empirical study reveals that emotions related to enjoyment may appear when the learners' skill is equal to or higher than the learning challenge. Nevertheless, boredom emotion may appear when learners perceive the courses are difficult but unimportant. These empirical survey results revealed the necessary of rethinking the appearance of boredom and enjoyment emotions in computer education.