• Title/Summary/Keyword: F-test

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Comparison of Alkali-Silica Reactivity for Mortar Bar and Concrete Prism Specimens Using Crushed Aggregates in Korea (국내 쇄석골재를 사용한 모르타르 봉 및 콘크리트 각주 시험편의 알칼리-실리카 반응성 비교)

  • Kim, Seong-Kwon;Yun, Kyong-Ku;Hur, In
    • International Journal of Highway Engineering
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    • v.14 no.5
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    • pp.93-99
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    • 2012
  • PURPOSES: The purpose of this study is to compare the alkali-silica reactivity for mortar bar and concrete prism specimens using crushed aggregates of 5 types in Korea. And the alkali-silica reactivity for those aggregates are measured by chemical test method. METHODS: The alkali-silica reactivity for those aggregates was measured by chemical test method of KS F 2545, mortar-bar test of KS F 2546, accelerated mortar-bar test method of ASTM C 1260 and concrete prism test method of ASTM C 1293, relatively. RESULTS: The alkali-silica reactivity for those aggregates was verified by chemical test of KS F 2546 and accelerated mortar-bar test of ASTM C 1260. However, it was not by mortar-bar test of KS F 2546 and concrete prism test of ASTM C 1293. CONCLUSIONS: The above results showed that relationship among the four test methods were very low. The results from 3 types of test methods using cement-aggregate combinations appeared to be different. Because the environmental conditions of test methods for measuring the alkali-silica reactivity such as equivalent alkali content(external source), humidity, temperature, and times were different though the aggregates were same. Moreover, alkali-silica reactivity showed the biggest impact when alkalis were supplied form outside and exposed to environmental conditions. The accelerated mortar-bar test method seems to be most appropriate test method for concrete structures exposed to alkali environment.

NBU- $t_{0}$ Class 에 대한 검정법 연구

  • 김환중
    • Proceedings of the Korean Reliability Society Conference
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    • 2000.04a
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    • pp.185-191
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    • 2000
  • A survival variable is a nonnegative random variable X with distribution function F and a survival function (equation omitted)=1-F. This variable is said to be New Better than Used of specified age $t_{0}$ if (equation omitted) for all $\chi$$\geq$0 and a fixed to. We propose the test for $H_{0}$ : (equation omitted) for all $\chi$$\geq$0 against $H_1$:(equation omitted) for all $\chi$$\geq$0 when the specified age $t_{0}$ is unknown but can be estimated from the data when $t_{0}$=${\mu}$, the mean of F, and also when $t_{0}$=$\xi_p$, the pth percentile of F. This test statistic, which is based on a linear function of the order statistics from the sample, is readily applied in the case of small sample. Also, this test statistic is more simple than the test statistic of Ahmad's test statistic (1998). Finally, the performance of this test is presented.

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A Study on the Test of Mean Residual Life with Random Censored Sample (임의 절단된 자료의 평균잔여수명 검정에 관한 연구)

  • 김재주;이경원;나명환
    • Journal of Korean Society for Quality Management
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    • v.25 no.3
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    • pp.11-21
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    • 1997
  • The mean residual life(MRL) function gives the expected remaining life of a item at age t. In particular F is said to be an increasing intially then decreasing MRL(IDMRL) distribution if there exists a turing point $t^*\ge0$ such that m(s)$\le$ m(t) for 0$$\le s$\le$ t $t^*$, m(s)$\ge$ m(t) for $t^*\le$ s$\le$ t. If the preceding inequality is reversed, F is said to be a decreasing initially then increasing MRL(DIMRL) distribution. Hawkins, et al.(1992) proposed test of H0 : F is exponential versus$H_1$: F is IDMRL, and $H_0$ versus $H_1$' : F is DIMRL when turning point is unknown. Their test is based on a complete random sample $X_1$, …, $X_n$ from F. In this paper, we generalized Hawkins-Kochar-Loader test to random censored data.

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Body Weight Control Behavior and Obesity Stress of College Women (여대생의 체중조절행위와 비만스트레스)

  • Kang, Yang-Hee;Kim, Kyung-Hee
    • The Journal of the Korea Contents Association
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    • v.15 no.2
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    • pp.292-300
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    • 2015
  • This study was conducted to investigate weight control behavior and obesity stress of college women. The data were collected from September 7 to September 13 of 2013 and the subjects were 213 college women in C city of Gyoung-nam Province. The data were analyzed by SPSS 20.0 program using descriptive statistics, t-test, ANOVA, Scheffe's test. The score of obesity stress was moderate($18.26{\pm}5.66$). The level of obesity stress was affected by various general characteristics and weight control behavior characteristics including economic status(F=3.99, p=0.020), figure recognition(F=14.41, p<.001), satisfaction of body figure(F=15.88, p<.001), interest of weight control(F=4.82, p=.001), control of food amount(F=2.41, p=.050), body figure compulsion(F=24.06, p<.001), experience of dieting (F=6.04, p<.001), sleeping hours(t=2.10, p=.036), desired losing weight (F=10.47, p<.001). Therefore, it is necessary to be considered these variables during development of body weight control programs for college women.

Rubber Packing Damage Test Report for Procedure of Forebody Erection in the Sea (해상탑재 DAM공법에 따른 선체외판 선저부위의 도막박리 및 밀림방지 대책)

  • Kim Young-Nam;Im Myung-Soo;Yea Weon-Bae
    • Special Issue of the Society of Naval Architects of Korea
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    • 2005.06a
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    • pp.144-150
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    • 2005
  • The size of ship is being larger than the past in the shipping industry thanks to the increased quantity of goods transported by ship. Therefore, HHIC (Hanjin Heavy industries & Construction co., LTD) invented innovative construction method, so called 'DAM', to build a ship which is longer than the length of the HHIC's dry dock. On Erection at the sea by the application of DAM Method, Squeezing & Detachment of A/F film may occur as a result of the wave and the constriction between A/F film pre-applied on the side shell and DAM's Rubber Packing. Thus, the test for finding the minimum curing time of A/F film was performed to protect Squeezing & Detachment of A/F film on the hull. To verify the soundness of paint and to find the optimum condition during the erection period of the DAM, laboratory test was carried out under no immersion condition through the application of various coatings on the Rubber Packing. And two methods were selected from the results of laboratory test for actual MOCK-UP Test. In addition, the test for the film profile per temperature of silicone A/F coat and the film Squeezing was performed.

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V/F Converter Design and Error Compensation of KSR-III Inertial Navigation System (과학로켓 관성항범장치의 V/F 변환기 설계 및 오차보상기법)

  • 김천중;조현철;노웅래;김동승
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.31-31
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    • 2000
  • In this paper, Ive design and test the V/F converter for KSR-III INS using commertial INC, VFC110, AD652. The test result shows that performance of AD652 is better than that of VFC110. Through the calibration of V/F converter, we show that the designed V/F converter has a good performance and is usable for KSR-III.

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An Experimental Study on the Structural Behavior of Reinforced Concrete Compressive Members Rehabilitated with Carbon Fiber Laminate (탄소섬유판으로 횡보강된 콘크리트 압축부재의 구조거동에 관한 실험적 연구)

  • Lee, Hee-Kyoung;Kim, Sung-Chul;Yoo, Seong-Hoon;Kim, Joong-Koo;Chung, Lan
    • Proceedings of the Korea Concrete Institute Conference
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    • 1997.10a
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    • pp.679-684
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    • 1997
  • In this study, compressive strengths of reinforced concrete compression members rehabilitated with C.F.L. were analyzed from the test. Test parameters are spacing, spliced length, and section area of rehabilitation material. Displacement, failure load were measured during test. The failure mode and ultimate load were analyzed from these measured data. Test result shows that closer spacing of C.F.L. is more effective. strengthening with 1-ply C.F.L. is more effective than that of specimen with 2-ply C.F.L. The compressive capacity of specimen spliced ($\pi$.D)/2 shows almost similar strength to that of non-spliced specimen. The ultimate load carrying capacity of specimen strengthened with C.F.L. is increased to 1.11~1.68 times of that of non-rehabilitation specimen.

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Concurrent Validity between Figure-of-8 Walking Test and Functional Tests Included Tasks for Dynamic Balance and Walking in Patient with Stroke (뇌졸중 환자에서 8자 모양 경로 보행 검사의 동시 타당도 연구)

  • Kim, Joong-Hwi;Park, Ji-Won
    • The Journal of Korean Physical Therapy
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    • v.24 no.5
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    • pp.325-333
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    • 2012
  • Purpose: The purpose of this study was to determine the concurrent validity between Figure-of-8 Walking Test (F8W), Berg Balance Scale (BBS), Four Squared Step Test (FSST), and Timed UP and GO Test (TUG) in patients with stroke. Methods: Forty two participants (26 men, 16 women, $55.0{\pm}11.72$) with at least three months post stroke who were able to walk at least 10 m without walking aid participated in this study. Assessment of concurrent validity between the F8W (time and steps) and BBS was performed using Spearman rank order correlation and between the F8W (time and steps), FSST and TUG assessed using Pearson correlation. Results: The time of the F8W showed correlation with BBS (r=-0.46, p<0.01), FSST (r=0.64, p<0.01), and TUG (r=0.81, p<0.01), and steps of the F8W showed correlation with BBS (r=-0.43, p<0.01), FSST (r=0.47, p<0.01), and TUG (r=0.51, p<0.01). Conclusion: The F8W is a valid measure of balance and walking skill among patients with stroke and may provide complementary information with regard to dynamic balance and functional walking for the real life of stroke patients.

Smooth Tests for Seasonality (평활 계절성 검정)

  • Lee, Geung-Hee
    • The Korean Journal of Applied Statistics
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    • v.24 no.1
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    • pp.45-59
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    • 2011
  • When using X-12-ARIMA for seasonal adjustment, we usually check whether the series has stable seasonality or not via D8 F-tests, Kruskal-Wallis test, and the spectral diagnostics. In this paper, we develop several smooth tests for seasonality based on a Fourier series to improve the spectral diagnostics of X-12-ARIMA. A simulation study is conducted to compare five smooth tests for seasonality and X-12-ARIMA's D8 F-test an Kruskal-Wallis test. The simulation study shows that smooth tests for seasonality performed well compared with D8 F-tests and a Kruskal-Wallis test.

The Strength Properties of Permeable Hot Mix Asphalt for Surface Course (배수성 아스팔트 표층용 혼합물의 강도특성)

  • Lee, Kwan-Ho;Ham, Sang-Min
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.7
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    • pp.3296-3301
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    • 2011
  • The Porous pavement gains popularity because of several benefits. It is to minimize hydro-planning condition, spraying condition, and splash to increase friction resistance, and decrease noise. Also, other studies showed that it is important to have appropriate porosity to reduce noise and water flush. The purpose of this study is an evaluation on the mechanical properties of asphalt pavements for surface course. In this study the specimen was manufactured using the Gyratory compactor in order to compact the strengthened surface course that involved the two-layer pavement. This study is conducted by using Marshall stability test(KS F 2377), Impact resonance test, Schmidt hammer test(KS F 2730), and the Uniaxial compression test(KS F 2314). Using the Uniaxial compression test and Schmidt hammer test, the values of compressive strength and bearing capacity were measured, and the modulus of elasticity for each specimen was respectively measured using the Uniaxial compression test, Impact Resonance test.