1,133 research outputs found

    An application of clustering analysis to the comparison of mortality rates

    Get PDF
    Mestrado Bolonha em Actuarial ScienceThis work provides the study of dissimilarity between mortality rates in 116 countries. Mean Shift Algorithm and Principal Component Analysis processed efficiently to classify countries into clusters, which show the reduction of the rate of mortality in the last twenty years. The result reveals an evident difference in the children and adult groups among researched countries, while it is more difficult to classify the rate for the seniors. Although the mortality rate will gradually reduce through time, there are two distinguishable patterns for developing countries having high rates: in Africa, where the value is higher for children, and in East Asia, where the survival probability for the adult is lower. The main reasons for the high mortality value in researched countries are natural disasters, global pandemics, and low-quality life. We also provided an application of the methodology by estimating the expected value and standard deviation of survival probability in Portugal and Vietnam in the next ten years.info:eu-repo/semantics/publishedVersio

    Seismic study of shallow circular tunnel in Red River sand (Vietnam)

    Get PDF
    Attention should be paid to tunnels' seismic behaviour since many of them have been damaged by earthquakes. The paper presented a seismic study of a shallow circular tunnel by physical modelling on shaking table test. A small scale tunnel model of the Hanoi pilot metro line's underground segment was placed in the middle of a rigid soil container and buried in Red River sand (Vietnam). The table was vibrated along the soil container's long wall, with a simulated seismic wave created from the 1788 Tolmezzo (Italia) accelerogram. Five testing campaigns were executed, and the model's acceleration data were studied. The uni-directional vibration created by the shaking table caused the three-directional vibration of the physical model. The Fast Fourier Transform (FFT) frequency spectrum analyses were performed. The vibration characteristics of the model (i.e., frequency graph's structure, maximal acceleration, dominant frequency, strong-motion duration) in three orthogonal directions under the artificial earthquake action were compared. The obtained results proved the complicated seismic impacts on a shallow tunnel

    Correlation between Resilient Modulus MR and Deviator Stress for Subgrade soils of northern provinces in Vietnam

    Get PDF
    Recently, Resilient Modulus is applied in pavement structural design in Vietnam. The resilient modulus of subgrade soil is an essential input parameter for a flexible pavement design. The resilient modulus depends on soil properties, stress state, and soil type.  However, there is limited research on resilient modulus of soils and models to estimate resilient modulus in Vietnam. Therefore, in this study, soil samples were collected from two provinces in northern Vietnam, namely Bac Giang province and Ninh Binh province, and then physical and mechanical tests were conducted for these samples. In addition, a series of cyclic triaxial tests also conducted according to AASHTO T307 specification to obtain resilient modulus of these soils.  The results showed that the resilient modulus decreased with the increase of deviator stress for Bac Giang samples and increased with the increase of deviator stress in the case of Ninh Binh samples. Simple deviator stress models have developed to estimate a resilient modulus of soils in the area

    Correlation between Resilient Modulus MR and Deviator Stress for Subgrade soils of northern provinces in Vietnam

    Get PDF
    Recently, Resilient Modulus is applied in pavement structural design in Vietnam. The resilient modulus of subgrade soil is an essential input parameter for a flexible pavement design. The resilient modulus depends on soil properties, stress state, and soil type.  However, there is limited research on resilient modulus of soils and models to estimate resilient modulus in Vietnam. Therefore, in this study, soil samples were collected from two provinces in northern Vietnam, namely Bac Giang province and Ninh Binh province, and then physical and mechanical tests were conducted for these samples. In addition, a series of cyclic triaxial tests also conducted according to AASHTO T307 specification to obtain resilient modulus of these soils.  The results showed that the resilient modulus decreased with the increase of deviator stress for Bac Giang samples and increased with the increase of deviator stress in the case of Ninh Binh samples. Simple deviator stress models have developed to estimate a resilient modulus of soils in the area

    Refinement of an inverse analysis procedure for estimating tensile constitutive law of UHPC

    Get PDF
    As regard to cementitious composite materials added a certain dosage of fiber, estimation of tensile constitutive law through inverse analysis methods is no longer extraordinary. However, development or improvement to achieve an effective method for estimating such a tensile behavior of fiber reinforced concrete (FRC) or Ultra high-performance concrete (UHPC) is still an interesting topic to researchers. In this respect, the paper presents a development of inverse analysis method developed by Lopez to obtain the stress-strain behavior of UHPC from the four-point bending test. By applying optimization algorithm into the iterative procedure of method, an improvement could be obtained for the inverse analysis with a high degree of automation in calculation. A post-process treatment for inverse analysis results is also proposed to bring a finer agreement between the tensile behavior curve obtained by the inverse analysis and result curve of uniaxial tensile test (UTT). The effectivity of process is shown through a comparison between the result obtained by the proposed method and the result in Lopez’s public paper

    Refinement of an inverse analysis procedure for estimating tensile constitutive law of UHPC

    Get PDF
    As regard to cementitious composite materials added a certain dosage of fiber, estimation of tensile constitutive law through inverse analysis methods is no longer extraordinary. However, development or improvement to achieve an effective method for estimating such a tensile behavior of fiber reinforced concrete (FRC) or Ultra high-performance concrete (UHPC) is still an interesting topic to researchers. In this respect, the paper presents a development of inverse analysis method developed by Lopez to obtain the stress-strain behavior of UHPC from the four-point bending test. By applying optimization algorithm into the iterative procedure of method, an improvement could be obtained for the inverse analysis with a high degree of automation in calculation. A post-process treatment for inverse analysis results is also proposed to bring a finer agreement between the tensile behavior curve obtained by the inverse analysis and result curve of uniaxial tensile test (UTT). The effectivity of process is shown through a comparison between the result obtained by the proposed method and the result in Lopez’s public paper

    COMPUTER INTERACTIVE TEACHING TECHNOLOGY FOR ELECTRONICS ENGINEERING UNIVERSITY.

    Get PDF
    Virtual reality technology currently tends to develop and apply strongly in all areas of social life. Therefore, the application of virtual reality technology in education and training is becoming more and more urgent. If we know how to effectively exploit and apply virtual reality technology to the design of the education and training process, the teaching of teachers and the acquisition of learners' knowledge will become easy, born dynamic. However, in order to achieve high efficiency, it is necessary to have a creative, flexible and appropriate application based on the actual conditions of each field, each school, the learning ability of learners, the ability to use using modern teaching facilities of teachers, specific subject
    corecore