• Title/Summary/Keyword: Dependency tests

Search Result 118, Processing Time 0.023 seconds

Nationality and Information Behavior: Comparing Korean and Japanese Students (정보행태에 있어 국민성의 의미 - 한국과 일본의 대학생에 대한 비교 분석 -)

  • Lee, Jae-Whoan
    • Journal of Korean Library and Information Science Society
    • /
    • v.41 no.3
    • /
    • pp.185-203
    • /
    • 2010
  • This study discusses the meanings of nationality in information behaviour. In this study nationality was represented by citizenship and group personality(here, dependency) Surveys were conducted for data collection, and a questionnaire were completed by 331 participants(158 Korean students and 183 Japanese students). Simple frequency tests and chi-square tests were conducted to examine the proposed relation between citizenship and information behavior, that between dependency and information behavior. Also conducted was two-way ANOVA test to examine the relative significance of two independent variables(citizenship and dependency) in information behavior. The results of chi-square tests showed that both variables have statistically significant relationship with information behavior although the relationship was partially significant. And the results of ANOVA test showed that between the two variables, citizenship was more significant than dependency.

  • PDF

Identification of the strain-dependent coefficient of permeability by combining the results of experimental and numerical oedometer tests with free lateral movement

  • Balic, Anis;Hadzalic, Emina;Dolarevic, Samir
    • Coupled systems mechanics
    • /
    • v.11 no.1
    • /
    • pp.1-14
    • /
    • 2022
  • The key parameter that affects the consolidation process of soil is the coefficient of permeability. The common assumption in the consolidation analysis is that the coefficient of permeability is porosity-dependent. However, various authors suggest that the strain-dependency of the coefficient of permeability should also be taken into account. In this paper, we present results of experimental and numerical analyses, with an aim to determine the strain-dependency of the coefficient of permeability. We present in detail both the experimental procedure and the finite element formulation of the two-dimensional axisymmetric numerical model of the oedometer test (standard and modified). We perform a set of experimental standard and modified oedometer tests. We use these experimental results to validate our numerical model and to define the model input parameter. Finally, by combining the experimental and numerical results, we propose the expression for the strain-dependent coefficient of permeability.

The Effects of Cell-Phone Dependency of Adolescents: Moderated Analysis of Self-Esteem (청소년의 휴대폰 의존에 미치는 영향: 자존감의 조절효과 검정)

  • Shim, Hyun-Jin;Rhee, Hyun-Sill
    • The Korean Journal of Health Service Management
    • /
    • v.11 no.2
    • /
    • pp.117-127
    • /
    • 2017
  • Objectives : This study aimed to identify factors of adolescents' cell-phone dependency using Agnew's General Strain Theory (GST) and the perspective of adolescents' micro-systems. A second aim was to verify the moderating effect of self-esteem. Methods : In total, 2,046 students who participated in a study on KCTPS mid. 1 panel 3 Wave by the National Youth Policy Institute were examined in this research. Data were analyzed through descriptive statistics, factor analysis, reliability tests, and hierarchical linear regression using SPSS Ver. 22.0. Results : The strain factors had a positive effect on adolescents' depression, and depression had a positive effect on cell-phone dependency. In addition, self-esteem had a negative moderating effect between depression and cell-phone dependency. Conclusions : Factors of cell-phone dependency were identified. The findings of the study indicate that an intervention is required to lower strain and depression and to enhance self-esteem among adolescents.

A tensile criterion to minimize FE mesh-dependency in concrete beams under blast loading

  • Gang, HanGul;Kwak, Hyo-Gyoung
    • Computers and Concrete
    • /
    • v.20 no.1
    • /
    • pp.1-10
    • /
    • 2017
  • This paper focuses on the mesh-size dependency in numerical simulations of reinforced concrete (RC) structures subjected to blast loading. A tensile failure criterion that can minimize the mesh-dependency of simulation results is introduced based on the fracture energy theory. In addition, conventional plasticity based damage models for concrete such as the CSC model and the HJC model, which are widely used for blast analyses of concrete structures, are compared with the orthotropic model that adopts the introduced tensile failure criterion in blast tests to verify the proposed criterion. The numerical predictions of the time-displacement relations at the mid-span of RC beams subjected to blast loading are compared with experimental results. The analytical results show that the numerical error according to the change in the finite element mesh size is substantially reduced and the accuracy of the numerical results is improved by applying a unique failure strain value determined by the proposed criterion.

The Effects of a Smoking Cessation Program on Nicotine Dependency and Self-Efficacy for Adolescents (금연프로그램이 청소년 흡연자의 니코틴 의존도와 자기효능감에 미치는 영향)

  • Paek, Kyung-Shin
    • Research in Community and Public Health Nursing
    • /
    • v.16 no.3
    • /
    • pp.282-288
    • /
    • 2005
  • Purpose: This study was to verify the effects of a smoking cessation program for adolescents. Method: This study was designed to use one group with one pre-test and two post-tests. One post-test was done immediately after the completion of the program and the other after eight weeks. The subjects were 21 male high school students who were smokers when this study was carried out. The smoking cessation program consisted of 5 sessions with smoking cessation education and e-mail service after the program. Variables in this research were nicotine dependency (using Fagerstrom Tolerance Questionnaire) and self-efficacy. Data were analyzed by descriptive statistics and Wilcoxon signed rank test. Results: Immediately after the program and eight weeks later, nicotine dependency for continuous smokers decreased significantly (after the program: Z=-2.319, p=.020, eight weeks later: Z=-1.999. p=.046) and self-efficacy increased significantly (after program: Z=-3.024. p=.002. eight weeks later: Z=-2.381. p=.017). Conclusions: The smoking cessation program was effective in decreasing nicotine dependency in the continuous adolescent smokers and in increasing their self-efficacy, Further study needs to be made with a lager number of smoking adolescents using control group design.

  • PDF

Experimental Study on the Structural Behaviour of Rotary Friction Damper (회전형 복합마찰댐퍼 구조거동에 대한 실험적 연구)

  • Kim, Do-Hyun;Kim, Ji-Young;Kim, Myeong-Han
    • Journal of Korean Association for Spatial Structures
    • /
    • v.15 no.4
    • /
    • pp.73-80
    • /
    • 2015
  • The new rotary friction damper was developed using several two-nodal rotary frictional components with different clamping forces. Because of these components, the rotary friction damper can be activated by building movements due to lateral forces such as a wind and earthquake. In this paper, various dependency tests such as displacement amplitude, forcing frequency and long term cyclic loading were carried out to evaluate on the structural performance and the multi-slip mechanism of the new damper. Test results show that the multi-slip mechanism is verified and friction coefficients are dependent on displacement amplitute and forcing frequency except long term cyclic loading.

A Study on Field and Laboratory Test Methods to Obtain Non-linear Deformation Characteristics of Soft Rocks (퇴적연암의 비선형특성 조사.시험기법에 관한 연구)

  • 김유성
    • Geotechnical Engineering
    • /
    • v.12 no.5
    • /
    • pp.63-78
    • /
    • 1996
  • Various type of in-situ and laboratary tests were performed in order to evaluate the stiffness of sedimentary soft rock. In triaxial compression tests of sedimentary soft rocks, axial strains from the axial displacement of the loading piston or specimen cap conventionally were considerably larger than those measured. tocally on the lateral surfaces of specimen, due to the bedding errors at the top and bottom ends of a specimen. A local deformation transducer was used to measure axial strains free from the bedding error ranging from 0.001% to about 1%. In ultra-sonic wave tests, the elastic modulus of unconfined spec imens was smaller than that of confined specimens, due probably to microfracks. Young's modulus Ed from ultra-sonic wave tests and those at small local strains from triaxial tests were similar, both of which agreed very well with Young's modulus Er from field shear wave velocities. Young'a modulus from the field behaviour was virtually similar to that obtained by reducing Er based on the strain level-dependency of stiffness evaluated by the triaxial tests.

  • PDF

ONLINE TEST BASED ON MUTUAL INFORMATION FOR TRUE RANDOM NUMBER GENERATORS

  • Kim, Young-Sik;Yeom, Yongjin;Choi, Hee Bong
    • Journal of the Korean Mathematical Society
    • /
    • v.50 no.4
    • /
    • pp.879-897
    • /
    • 2013
  • Shannon entropy is one of the widely used randomness measures especially for cryptographic applications. However, the conventional entropy tests are less sensitive to the inter-bit dependency in random samples. In this paper, we propose new online randomness test schemes for true random number generators (TRNGs) based on the mutual information between consecutive ${\kappa}$-bit output blocks for testing of inter-bit dependency in random samples. By estimating the block entropies of distinct lengths at the same time, it is possible to measure the mutual information, which is closely related to the amount of the statistical dependency between two consecutive data blocks. In addition, we propose a new estimation method for entropies, which accumulates intermediate values of the number of frequencies. The proposed method can estimate entropy with less samples than Maurer-Coron type entropy test can. By numerical simulations, it is shown that the new proposed scheme can be used as a reliable online entropy estimator for TRNGs used by cryptographic modules.

An Experimental Study for the Shear Property and the Temperature Dependency of Seismic Isolation Bearings (지진격리받침의 전단특성 및 온도의존성에 대한 실험적 연구)

  • Cho, Chang-Beck;Kwahk, Im-Jong;Kim, Young-Jin
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.12 no.1
    • /
    • pp.67-77
    • /
    • 2008
  • Seismic isolation has been studied continuously as a solution of the seismic engineering to reduce the sectional forces and the damages of structures caused by earthquakes. To certify reliable design and installation of the seismic isolation systems, seismic isolation bearings should be fabricated under well planned quality control process, and proper evaluation tests for their seismic performance should be followed. In this study, shear property evaluation tests for the lead rubber bearings(LRB) and the rubber bearings(RB) were implemented and the temperature dependency tests were also implemented to evaluate the changes of shear properties according to the changes of temperature. After evaluation tests, the measured shear properties were compared to their design values and their deviation was analyzed comparing with the allowable error ranges specified in Highway Bridge Design Specifications. These results showed that a considerable number of isolation bearings have so large deviations from their design values that their error ranges were over or very close to the allowable ranges. And the test results for temperature dependency showed that the shear properties of isolation bearings would be changed in great degree by the change of temperature during their service period. If these two types of changes in their shear properties are superposed, it would possible that the changes of shear properties from their original design values are over than 50%.

An Experimental Study on the Dynamic Increase Factor and Strain Rate Dependency of the Tensile Strength of Rock Materials (암석재료 인장강도의 동적 증가계수 및 변형률 속도 의존성에 대한 실험적 연구)

  • Oh, Se-Wook;Choi, Byung-Hee;Min, Gyeong-Jo;Jung, Yong-Bok;Cho, Sang-Ho
    • Explosives and Blasting
    • /
    • v.39 no.1
    • /
    • pp.10-21
    • /
    • 2021
  • Brittle materials such as rocks and concretes exhibit large strain-rate dependency under dynamic loading conditions. This means that the mechanical properties of such materials can significantly be varied according to load velocity. Thus, the strain-rate dependency is recognized as one of the most important considerations in solving problems of blast engineering or rock dynamics. Unfortunately, however, studies for characterizing the dynamic properties of domestic rocks and other brittle materials are still insufficient in the country. In this study, dynamic tensile tests were conducted using the Hopkinson pressure bar apparatus to characterize the dynamic properties of Geochang granite and high-strength concrete specimens. The dynamic Brazilian disc test, which is suggested by ISRM, and the spalling method were applied. In general, the latter is believed to have some advantages in experiments under high-strain rate deformation. It was found from the tests that there were no significant difference between the dynamic tensile strengths obtained from the two different test methods for the two materials given. However, this was not the expected result before the tests. Actually, authors expected that there be some differences between them. Hence, it is thought that further investigations are needed to clarify this results.