Papers by Keyword: Composite Model

Abstract: Recurrent events data refers to the observation of individuals, which contains the recurrent event time of interest. In this paper, we focus on the statistical analysis of recurrent event, and present a composite model based on the proportional intensity function and additive hazard function, and then prove the consistency and asymptotic properties of the estimation under certain regularity conditions.

Abstract: This paper mainly discusses a composite model which the end time is an additive hazard function and the recurrent event process is a proportional intensity function, the covariate is time-independent, and censoring is dependent on recurrent events process and end times. Based on the likelihood method, Delta method, U-statistic method and the idea of general estimation equation, the estimation of unknown parameters and unknown functions in this composite model is proposed.

Abstract: Flapping wing aerial vehicles continue to be a growing field, with ongoing research into unsteady, low Reynolds number aerodynamics and micro fabrication. However research into deformation and stress of flapping wing continues to lag, especially based on composites model. One flapping cycle was divided into twelve segments, and maximum defmortion and stress were calculated in each segment. The results show that the maximum sdeformation at the beginning stages of downstroke is 19% larger than the maximum deformation at the beginning stages of upstroke, and the maximum stress at the beginning stages of downstroke is 29.9 larger than the maximum stress at the beginning stages of upstroke. This research is helpful to answer that why insect wings are so perfect through long evolution, thus improving the design of flapping-wing aerial vehicles.

Abstract: Since the 21st century, with the rapidly development of the Internet, it promotes the rapidly development of electronic commerce. In present e-commerce activities,it mainly includes government agencies and online shopping which draw people's special attention to it . This study analyzes the statistical data in a certain time the user access to online shopping site and puts forward that this law according with certain probability density distribution conclusion. This paper plans a table which pushed a compound probability distribution model through the basic probability density function in order to adapt to the search engine's rule.It finally applied the composite model to probability distribution of people use search engine successful and found that the use of composite model prediction value are at risk than other models. probability distribution of the users in a certain time shopping can be pointed out which has a certain guiding significance on the search engine marketing model in electronic commerce environment.

Abstract: The compressive strength development process of recycled coarse aggregate concrete (RCAC) directly affects the safety of the engineering structures, which is an important research topic in the concrete mechanics. According to the statistics of the experimental results, the development mechanism principle of the compressive strength of RCAC gradually increasing with curing time was analyzed. The mathematical property was introduced to reveal the defects of the traditional hyperbolic model of the time-relative compressive strength (TRCS), and to point out that the mathematical nature of the ideal TRCS model should have. A new CES model was presented for TRCS. The mathematical analysis shows that the hyperbolic model is a special case of the CES model, and in another hand the CES model overcomes the defects of the hyperbolic model.

Abstract: On the base of studying on mechanism of the deformation and bearing capacity of vibro-replacement stone column foundation thoroughly, the assumptive conditions are presented. The composite 2-dimension numerical model of the stone column is established, this model considers the couple of stress-strain with Biot consolidation and the reinforced efficiently, the finite element analysis program is developed according to this model. The reliability and validity of APOSE is verified by a simple example. The results show that APOSE can be applied to analyze the consolidation and subsiding for vibro-replacement stone column, etc

Abstract: Mathematical model for skeleton stress-strain curve under dynamic loading (SSSC) is one important issue to study the dynamic behavior of soft soil. Based on mechanism of developing process, primary mathematical behavior that SSSC model should meet is analyzed. Mathematical investigation on two conventional SSSC models, namely hyperbolic model and exponential model, is conducted. Dynamic stress index is proposed and employed to signalize the shortcomings of two conventional models. A composite tangent-exponent model for SSSC with three parameters is established, which is a monotone increasing and up limited function. The new model can overcome conventional shortcomings. Finally, good agreement between investigated and new model fitted data has been found out.

Abstract: Fully reversed tension-compression fatigue tests were performed on solid-solutioned Al-0.7mass%Mg single crystals with a single slip orientation under constant plastic-strain amplitudes. Dislocation microstructures were quantitatively examined by transmission electron microscopy. The cyclic stress–strain curve (CSSC) exhibited three distinct regions with a short plateau region in the intermediate plastic-strain amplitude range, and the plateau stress was 26MPa. Characteristic microstructures were developed corresponding to the three regions in the CSSC. Vein structure was observed at the low strain-amplitude region. In the plateau regime, the persistent slip bands (PSBs) were observed. Labyrinth structure was also observed at the higher strain-amplitude region. The plateau stress, the cyclic flow stress of PSBs, can be explained by considering not only the Orowan bowing stress and the dipole passing stress of screw dislocations but also solid-solution hardening by Mg atoms.

Abstract: The composite model of plastic deformation is regarded as a realistic approximation of creep behaviour at elevated temperatures in a well-developed substructure consisting of dislocationdense subgrain boundaries (hard regions) and subgrain interiors (soft regions) with relatively low dislocation density. In the present contribution, the model is applied for an estimation of internal stresses that are experimentally measured by the dip-test technique. Two situations are considered within the model: (i) the density of moving dislocations is the same in both hard and soft regions and (ii) the density of moving dislocations is proportional to the local density in the respective region. The model enables to express the internal stress in terms of microstructural variables found by independent microscopic observations. It is shown that the magnitude of volume fraction of hard and soft region in the composite model has only a small effect on the value of internal stress.