Papers by Keyword: Randomness

Abstract: In the paper, the relationship between the grain size and fatigue life are studied. To specify the initial and short crack propagation life of low carbon steel material, three methods are used in the simulation. At first, the K. Tanaka’s model is introduced to calculate the fatigue life of a grain. Then, the Voronoi Diagram is used to generate the microstructure of grains. At last, a criteria to specify the short crack is proposed. Based on these methods, the numerical simulation is conducted. With the help of the process, the grain sizes are generated randomly in order to specify how grain sizes effect fatigue life. The computational results are in good agreement with the experimental data. The results show that the randomness of fatigue life is closely related to the randomness of grain sizes.

Abstract: This paper takes Unit Commitment with Wind Power Electric Systems for instance and studies the application of relevant indicators in the short run adequacy decisions. It first conducted running adequacy assessment of the RBTS system, and then given unit combination solutions in the ample index constraints. The results show that the relevant indicators can be more accurately to depict the influence of random factors on system operation adequacy, and Unit Commitment decisions based adequacy index is able to give a unit commitment program at different adequacy levels. The research results provide a set of assessment indicators and assessment methods for short running adequacy problems of random fluctuations power accessing to large-scale power systems..

Abstract: The "birth and death" process of colony is a kind of widely used model, especially in the field of biology, biological system engineering, population science, and so forth. The “birth and death” process of colony is complicated stochastic process, a Markovian process with the nature of Poisson. And it can be studied by the theory and method of Markovian decision programming.

Abstract: Effects of laminate misalignment on the thermoelastoviscoplastic properties of ultrafine plate-fin structures are investigated using a homogenization theory for thermoelastoviscoplasticity. For this, a homogenization theory for time-dependent materials is combined with a homogenization theory for thermoelasticity. Moreover, the substructure method is introduced into the theory to deal with the random laminate misalignment in ultrafine plate-fin structures. The present method is then applied to the analysis of thermoelastoviscoplastic behavior of ultrafine plate-fin structures made of a Ni-based alloy subjected to a macroscopic temperature increment from 20 to 200. The number of fin layers in a unit cell is five kinds, i.e. N = 10, 20, 30, 40 and 50, for each of which, twenty patterns of random laminate misalignment are considered. In addition, five cases of periodic laminate misalignment are also considered for comparison. The results reveal the effects of the laminate misalignment on the macroscopic and microscopic thermoelastoviscoplastic properties of ultrafine plate-fin structures.

Abstract: This paper shows the research on hardware random number generator (HRNG). As truly random numbers are strongly required in encryption and computer simulation areas, developing a simple and inexpensive HRNG has significant value. The whole system is divided into the noise generating module and the processing module. After the numbers are generated, a randomness test has been carried out which indicates that the random numbers generated are truly random. It is concluded that the final product of this HRNG meets the requirements of the objectives.

Abstract: Randomness is an accidental, an event with a probability demonstrated uncertainty. We know CPM method does not consider the resource constraints. This deficiency can be solved by the critical chain technology. We can get more than a critical chain. In order to solve this problem, We can use the optimal method of stochastic process to schedule critical chain.

Abstract: The randomness of electrostatic discharge current waveform is considered to present great problems in experimental data analysis and drawing conclusions. In order to solve this problem, we measured a large amount of data in electrostatic discharge experiments. The experimental data are studied by statistical methods and new parameters of waveform dispersion, the waveform error within group (E_w) and the waveform error between groups (E_b), are defined in this paper. And peak current, rise time, 30ns current, 60ns current are also analyzed. The results indicate that statistical analysis plays an important role in the experimental study of electrostatic discharge and the parameter variations of contact discharge equivalent circuit might be an important factor of the randomness of electrostatic discharge current waveform.

Abstract: Using the pseudo-excitation method, a simple model was built to study the seismic response of buried pipeline laid through three-soil site for vertical incidence of seismic waves. Seismic ground motions are considered as stationary stochastic processes, and the cross-PSD function was established based on auto-PSD model, coherence model, and site response model. The results show that the peak bending stress depends on the properties of adjacent soils and the width of middle-soil, and appears in the pipeline near the soil interfaces.

Abstract: A synthetic assessment method and systematic procedure are developed in this paper based on cloud theory. The calibration results work well in one building site of Bohai Bay. This shows the presented method has advantages of concision and easy-operation, and the randomness and ambiguity can reacted in the assessment procedure, so the assessment results are practical significance.

Abstract: This paper deals with the evaluation of response variability of composite plates due to randomness in the Poisson’s ratio in particular for the out-of-plane behavior. To this end, we adopt the weighted integral stochastic finite element (SFE) scheme and derive a SFE formulation employing Taylor’s expansion on the random Poisson’s ratio and displacement vector as well. In case of composite plates, the stiffness of the structure is affected by the stacking scheme of individual layers. This means that even the plates subjected only to in-plane loading can show out-of-plane behavior. In order to investigate this phenomenon, we chose two example plates with symmetric and asymmetric stacking scheme. A detailed explanation on the results is addressed for the plates under consideration.