• Title/Summary/Keyword: Simple test

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Evaluation of Flow Stress of Metal up to High Strain (금속소재의 고변형률 영역 유동응력선도 평가)

  • Lee, S.K.;Lee, I.K.;Lee, S.Y.;Lee, S.M.;Jeong, M.S.
    • Transactions of Materials Processing
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    • v.29 no.6
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    • pp.316-322
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    • 2020
  • The flow stress curve is usually determined via uniaxial tensile or simple compression test. However, the flow stress curve up to high strain cannot be obtained using these two tests. This study presents a simple method for obtaining the flow stress curve up to high strain via FE analysis, a simple compression test, and an indentation test. In order to draw the flow stress curve up to high strain, the indentation test was carried out with the pre-stained specimen using the simple compression test. The flow stress curve of Al6110 was evaluated up to high strain using the proposed method, and the result was compared with the flow stress curve of the uniaxial tensile test of the initial material.

A Simple Chi-squared Test of Multivariate Normality Based on the Spherical Data

  • Park, Cheolyong
    • Communications for Statistical Applications and Methods
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    • v.8 no.1
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    • pp.117-126
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    • 2001
  • We provide a simple chi-squared test of multivariate normality based on rectangular cells on the spherical data. This test is simple since it is a direct extension of the univariate chi-squared test to multivariate case and the expected cell counts are easily computed. We derive the limiting distribution of the chi-squared statistic via the conditional limit theorems. We study the accuracy in finite samples of the limiting distribution and then compare the poser of our test with those of other popular tests in an application to a real data.

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Comparing More than Two Agreement Measures Using Marginal Association

  • Oh, Myong-Sik
    • Communications for Statistical Applications and Methods
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    • v.16 no.6
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    • pp.1023-1029
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    • 2009
  • Oh (2009) has proposed a likelihood ratio test for comparing two agreements for dependent observations based on the concept of marginal homogeneity and marginal stochastic ordering. In this paper we consider the comparison of more than two agreement measures. Simple ordering and simple tree ordering among agreement measures are investigated. Some test procedures, including likelihood ratio test, are discussed.

A simple test method to assess slump flow and stability of self-compacting concrete

  • Bouziani, Tayeb
    • Computers and Concrete
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    • v.21 no.2
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    • pp.111-116
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    • 2018
  • Establishment of test methods to assess the fresh properties of self-compacting concrete (SCC) are required to ensure the homogeneity in fresh and hardened states. This paper discusses the suitability of a simple test method for assessing the slump flow and stability of SCC by testing on self-compacting mortar (SCM) fraction. The proposed test method aims at investigating slump flow diameter test and sieve stability test of SCC by testing SCM fraction with a plunger penetration apparatus. A central composite modeling design was performed to evaluate the effects of water/cement ratio (W/C), superplasticizer dosage (SP) and powder marble content (MP) on slump flow diameter, stability and plunger penetration test of fresh SCC. The responses of the derived statistical models are slump flow (Sf), sieve stability (S) and plunger penetration (P). Relationships obtained in this study show acceptable correlations between plunger penetration test value and slump flow diameter test results and stability. It should note that the developed relationships are very useful to predict slump flow diameter and stability of studied SCC mixtures by carrying out a simple plunger penetration test on its mortar, which can save labour and time in laboratory experiments.

Development of a Simple Manoeuvring Model for Ship-handling Simulator by Analytical Methods (해석적 방법에 의한 선박 시뮬레이터용 단순 조종 모델 개발)

  • Kim, Dong-Jin;Yeo, Dong-Jin;Rhee, Key-Pyo
    • Journal of the Society of Naval Architects of Korea
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    • v.47 no.6
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    • pp.776-781
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    • 2010
  • In the ship-handling simulator, it is important for a ship manoeuvring model to represent the dynamic characteristic of a ship and to be simple for reducing calculation time. Especially, even if principal dimensions of a ship are given in initial design stage, or manoeuvring test data are only given by model or real ship's trials, simulations are often needed to check the manoeuvrability of a ship. In this paper, a simple manoeuvring model based on turning test data of a ship is mathematically developed. And the simulation results are verified by comparing with turning test results of a real ship.

Effective test of lacquer in marine diesel engines

  • Hong, Sung-Ho;Ju, Seung-Hwan
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.9 no.2
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    • pp.199-208
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    • 2017
  • We perform an experiment on lacquer formation with simple test device. The anti-lacquer is one of important issues to increase durability, and to improve performance in the engines because the lacquer formation cause sticking of fuel injection pump, scuffing of cylinder liners, and increase of lubricant oil consumption in the marine diesel engines. We suggest this simple test in order to save enormous experimental cost in marine diesel engines, and in order to have ease in performing the various tests. The influences of the Base Number (BN) of lubricant oils and the sulfur content of fuel oils in the formation of lacquer are investigated. In order to investigate physical and chemical properties of lacquer, we perform a variety of tests such as, visual inspection, EDS. In addition, we investigate adhesion of lacquer by pull-off test quantitatively, and perform dissolution test with dilute sulfuric acid.

A Simple Nonparametric Test of Complete Independence

  • Park, Cheol-Yong
    • Communications for Statistical Applications and Methods
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    • v.5 no.2
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    • pp.411-416
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    • 1998
  • A simple nonparametric test of complete or total independence is suggested for continuous multivariate distributions. This procedure first discretizes the original variables based on their order statistics, and then tests the hypothesis of complete independence for the resulting contingency table. Under the hypothesis of independence, the chi-squared test statistic has an asymptotic chi-squared distribution. We present a simulation study to illustrate the accuracy in finite samples of the limiting distribution of the test statistic. We compare our method to another nonparametric test of complete independence via a simulation study. Finally, we apply our method to the residuals from a real data set.

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Forming Limit Diagram Measurement of Tube for Tube Hydroforming Process (하이드로 포밍용 튜브의 성형 한계선도 측정)

  • Han, S.S.
    • Transactions of Materials Processing
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    • v.15 no.6 s.87
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    • pp.467-472
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    • 2006
  • The forming limit diagram of tube is required for the part design and the formability analysis of tube hydroforming. The finite element analyses of simple bulge test were done to obtain the various strain combinations on FLC. The finite element analysis results were shown that the bursting at various strain combinations could be induced by simple bulge test. The experiment oi tube bulge test was carried out according to the test condition that obtained from finite element analysis and the left hand side of forming limit diagram was built.

A study of dynamic peoperties in cyclic simple shear test (동적단순전단 시험기를 이용한 매립지반 거동특성에 관한 연구)

  • Kim, Sung-Jin;Ryu, Jeong-Ho;Park, Yo-Hwan;Kim, Jin-Man
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.1422-1430
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    • 2008
  • Cyclic simple shear test apparatus was used to investigate the dynamic response of liquefiable soils as reclamation material. The specimen were reclamation using simple air-pluviation method. The confining stress was applied the range of 100 kpa to 200 kpa. The resulted strain was in the range of $10^{-3}$ ~ 5 %. Based on these test results modulus reduction curve, damping curve and cyclic strength curve were developed. The developed curves were compared to those already available in literature. The obtained curves can be applied to FEM or equivalent linear analysis such as SHAKE for ground response analysis.

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Development of a Simple Screening Test for Identifying Korean Elderly at Risk of Undernutrition (한국 노인의 영양부족위험 진단을 위한 간이조사표의 개발)

  • 김기남;현태선;이정원
    • Korean Journal of Community Nutrition
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    • v.5 no.3
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    • pp.475-483
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    • 2000
  • The develop a simple screening test for identifying Korean elderly at risk of undernutrition, the data of the health-related habits, dietary behaviors and nutrient intakes of the elderly in Chongju were analyzed. Two risk indicators, mean adequacy ratio (MAR) and the respondents perceived health, were used to detect the undernutrition risk of the elderly. In order to select a list of questions for the test, factors a affecting nutritional status and items investigated in previous nutrition surveys of the elderly were considered, and 21 questions were primarily selected. A multiple regression and stepwise regression analysis were used to take out the weak predictors of poor nutrient intake, and to give item weights to the strong predictors, and a list of 17 questions was finally adopted. To determine the cut-point of the test score, sensitivity, and positive predictive values were calculated. The Simple Screening Test developed in this study is a brief, easily scored tool to predict poor nutrient intake and the perceived health status of the elderly. The test may provide a basis of further comprehensive nutritional assessment or intervention planning, if necessary, for those who are diagnosed ad "high risk". The test, however, needs to be independently validated by other groups of individuals.dividuals.

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