• Title/Summary/Keyword: Ratio Test

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A Statistical Analysis of the Distribution of Sasang Constitutions in Iksan Wonkwang Oriental Medicine (익산원광한의원 내원환자의 체질분포에 관한 통계적 분석)

  • 김종열;김홍기
    • The Journal of Korean Medicine
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    • v.24 no.3
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    • pp.118-129
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    • 2003
  • Objective : To learn the distributional characteristics of Sasang constitutions, Methods : We statistically analyzed those 1338 patients who had been treated at Iksan Wonkwang Oriental Medicine during the period of three years from 2000 to 2002. The data were obtained through the electronic chart developed by Kim Jong- Yeol, and analyzed using the statistical Package SPSS. Results : The distributional ratio of Soeumin : Soyangin : Taeumin was 22.8 : 29.2 : 47.8. Thus the hypothesis : 'the distributional ratio of Soeumin : Soyangin : Taeumin is 2 : 3 : 5' was barely rejected by $x^2$ test for goodness-of-fit at the significance level of 5 %. When $x^2$ test for homogeneity was applied, the distributional characteristics between women and men were different and the distributional characteristics among several age groups were different under significance level of 5%. Conclusion : Though the hypothesis: 'the distributional ratio of Soeumin : Soyangin : Taeumin is 2 : 3 : 5' was rejected by $x^2$ test at the significance level of 5%, the observed distributional ratio was not so far away from the hypothesis.

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The Existence of Random Walk in the Philippine Stock Market: Evidence from Unit Root and Variance-Ratio Tests

  • CAMBA, Abraham C. Jr.;CAMBA, Aileen L.
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.10
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    • pp.523-530
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    • 2020
  • The efficient market hypothesis explains the random walk hypothesis suggesting that stock prices are independent of each other, hence, it is impossible to earn abnormal profits. The positive effect of a well-functioning and highly efficient stock market on the performance of an economy motivated the Philippine Stock Exchange to pursue massive modernization initiatives. This research provides evidence of the existence of random walk in the Philippine stock market employing the Augmented Dickey-Fuller (1981) and Phillips-Perron (1988) unit root tests, the Lo-MacKinlay's (1988) conventional variance ratio test, and Chow-Denning's (1993) simple multiple variance ratio test. Results of the ADF and PP unit root tests confirm the necessary condition for a random walk. The Chow-Denning (1993) maximum /z/ statistic and the Wald test statistic as in Richardson and Smith (1991) for the joint hypotheses and the Lo and MacKinlay (1988) individual statistics variance ratio test generally accepted the null hypothesis of a random walk. That is, the unit root and variance ratio tests consistently indicate that the null hypothesis of random walk cannot be rejected. The existence of a random walk in weak-form efficiency can be attributed to market liquidity as a result of continuous development and modernization of the Philippine equity market.

A Study on the Loading Capacity Standard of Bi-directional Pile Load Test (BD PLT) (양방향말뚝재하시험의 재하용량 기준에 관한 연구)

  • Choi, Yongkyu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.6C
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    • pp.379-388
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    • 2008
  • In the bi-directional pile load test (BD PLT) for pile load tests of Mega pile foundations, loading capacity standard is not specified exactly. Therefore there are so many confusions in performing the BD PLT and variations up to maximum 2 times in loading capacity are come out. In this study, standards of bi-directional pile load test (BD PLT) were considered. Based on cases of the bi-directional pile load test performed in domestic areas, maximum equivalent test load, test load increasing ratio, loading capacity increasing ratio and sufficiency ratio of design load were analyzed. It could be known that the loading capacity standard of bi-directional pile load test must be defined as 1-directional loading capacity and also must be established as more than 2 times of design load.

A Study on the Proper Pore pressure ratio in Continuous Loading Consolidation tests (연속재하 압밀시험에서 적정 간극수압비에 관한 연구)

  • Chae, Sum-Sik;Lee, Song
    • Proceedings of the KSR Conference
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    • 2002.05a
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    • pp.271-276
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    • 2002
  • Continuous loading is applied the sample has been developed to overcome some of the problems associated with the incremental loading consolidation test. Therefore, it is able to reduce the test time and provide a well defined the curve of effective stress versus strain due to continuous stress-strain points. Also, the constant rate of strain consolidation(CRSC) test has been accepted widely as a standard method in foreign countries because of its many advantages. However, in Korea the CRSC test has not been used in engineering practice and experimentally verified. Because there is not a precise criterion of testing despite consolidation characteristics are influenced on strain rate and Pore pressure ratio. Consequently, it is difficult to apply in engineering practice. In this study, artificial neural networks are applied to the estimation of th proper strain rate and pore pressure ratio of the CRSC test. This study shows the possibility of utilizing the artificial neural networks model of estimation of the strain rate and pore pressure ratio in the CRSC test.

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Analysis of Maximum Generating Power Drop of PV Module Under the Continuous Artificial Light Irradiation Test Condition (연속 광조사 조건에서의 태양전지모듈의 연간 최대출력 저하율 변화 예측 분석)

  • Kim, Kyungsoo;Yun, Jaeho
    • Current Photovoltaic Research
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    • v.6 no.3
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    • pp.69-73
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    • 2018
  • PV system is consisted with PV module, inverter and BOS(balance of system). To have robustic operation more than 20 years, the expected and guaranteed durability and reliability of products should be met. Almost components of PV system are qualified through IEC standards at test laboratory. But the qualification certificate of product does not ensure long-term nondefective operation. PV module's expected life time is nowadays more than 20 years and annual maximum power degradation ratio would be less than -1%. But the power degradation ratio is basically based on real data more than several years' record. Developing test method for ensuring annual maximum power degradation ratio is very need because there are many new products every month with new materials. In this paper, we have suggested new test method under continuous artificial light irradiation test condition for analyze expected maximum power drop ratio.

Poisson's Ratio Prediction of Soil Using the Consolidation Undrained Triaxial Compression Test (압밀비배수 삼축압축실험을 이용한 지반의 포아송비 예측)

  • Lim, Seongyoon;Yu, Seokchoel;Kim, Yuyong;Kim, Myeonghwan
    • Journal of The Korean Society of Agricultural Engineers
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    • v.62 no.4
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    • pp.45-51
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    • 2020
  • The poisson's ratio was obtained from the effective vertical stress and horizontal stress of consolidation-undrained test. It was analyzed void ratio verse poisson's ratio. At the result, the effective friction angle was increase with relative density increased, was decreased the poisson's ratio. The empirical equation of void ratio and poisson's ratio was showed very high correlation r2=0.846. The empirical equation was showed that the smaller the void ratio in the fine grained soil than granular soil. In the case of 0.85 times the correlation analysis equation of granular and fine grained soil, the experimental results were shown very similarly. In especially, the poisson's ratio prediction results was shown within 5% of the error range, was revalidation 0.85 times the correlation analysis equation using the void ratio. In this study, correlation analysis equation of the granular and fine grained soil was more reliability of the poisson's ratio prediction results apply to the void ratio than dry unit weight.

Evaluation of Coagulants Dispersion in Pump Diffusion Mixer for Water Treatment (CFD모사 기법을 이용한 Pump Diffusion Mixer내의 응집체 확산분포에 대한 평가)

  • Park, Young-Oh;Park, No-Suk;Kim, Seong-Su;Kim, Ki-Don;Lim, Kyung-Ho
    • Journal of Korean Society of Water and Wastewater
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    • v.22 no.1
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    • pp.49-63
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    • 2008
  • The objectives of this research were to evaluate the pressurized/the main inlet water flowrate ratio which have been used as the most important parameter for operating the pump diffusion mixer until now, to suggest the alternative operating parameter and the relating criteria if the flowrate ratio was not inadequate. For the objectives of this research, computational fluid dynamics (CFD) simulation was conducted for 21 cases of flowrate ratio in full-scaled pump diffusion mixer. From the results of CFD simulation, the local velocity gradient values were calculated in each case in order to analyze the simulation results in more detail. For verifying CFD simulation, wet test was conducted. The wet test was to measure the factual coagulant dispersion distribution at a distance of 5.4m from deflector. From both results of CFD simulation and wet test, flowrate ratio was inadequate as operating parameter or criteria, on the other hand the pressurized/the main inlet velocity ratio(dimensionless) was useful in predicting the performance of pump diffusion mixer. Also, the injected coagulant could be dispersed evenly in overall cross section on the condition that pressurized/the main inlet velocity ratio(dimensionless) is over at least 20.

ON TESTING THE EQUALITY OF THE COEFFICIENTS OF VARIATION IN TWO INVERSE GAUSSIAN POPULATIONS

  • Choi, Byung-Jin;Kim, Kee-Young
    • Journal of the Korean Statistical Society
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    • v.32 no.2
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    • pp.93-101
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    • 2003
  • This paper deals with testing the equality of the coefficients of variation in two inverse Gaussian populations. The likelihood ratio, Lagrange-multiplier and Wald tests are presented. Monte-Carlo simulations are performed to compare the powers of these tests. In a simulation study, the likelihood ratio test appears to be consistently more powerful than the Lagrange-multiplier and Wald tests when sample size is small. The powers of all the tests tend to be similar when sample size increases.

Regression Diagnostic Using Residual Plots

  • Oh, Kwang-Sik
    • Communications for Statistical Applications and Methods
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    • v.8 no.2
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    • pp.311-317
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    • 2001
  • It is necessary to check the linearity of selected covariates in regression diagnostics. There are various graphical methods using residual plots such as partial residual plots, augmented partial residual plots and combining conditional expectation and residual plots. In this paper, we propose the modified pseudolikelihood ratio test statistics based on these residual plots to test linearity of selected covariate. These test statistics which measure the distance between the nonparametric and parametric models are derived as a ratio of quadratic forms. The approximate distribution of these statistics is calculated numerically by using three moments. The power comparison of these statistics is given.

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A Study of Shear Resistance Characteristics using Shear Test Data with Stirrup (전단보강철근이 있는 기존 전단실험 자료를 이용한 전단특성에 관한 연구)

  • Shin Geun Ok;Lee Chang Shin;Jeong Jae Pyong;Kim Woo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05a
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    • pp.403-406
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    • 2005
  • This paper deals with the propriety of the shear test data with stirrup reported in ACI and ASCE structural journal and the shear resistance characteristics affected by compressive strength of concrere($f_{ck}$), shear span-to-depth ratio (a/d), tensile reinforcement ratio($\rho$), and shear reinforcement ratio($rho_{v}$). The analysis was accomplished by the 242 shear test data. The test data include the flexural failure data around 40$\%$.

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