International Journal of Modeling, Simulation, and Scientific Computing

Driver attention distraction (DAD) is a typical artificial factor traffic accident, and DAD monitoring can improve driving security. In this study, a method was developed for accurate DAD monitoring based on binocular vision. A binocular vision system was built, and camera parameters of the system were calibrated based on Open CV. In the method, the driver’s facial image is obtained by using active infrared imaging technology and preprocessed to locate the eye positions. The connected component labeling algorithm for binary images is used to pinpoint the eye locations. The characteristic information of the eye pupils is extracted with the least-squares ellipse fitting algorithm, and the characteristic information of the Purkinje image is obtained with the Harris corner detection algorithm. A DAD warning model based on the binocular vision system was established to evaluate the attention state of the driver.

Lifetime performance index is a powerful and effective way to analyze whether a product achieves the specified standards. In this paper, we investigate the lifetime performance index for the inverted exponential Rayleigh distribution using progressive type II censored sample data. The censored sample is able to greatly save the cost of the experiment and speed up the experiment. We derive the estimation value of lifetime performance index using the maximum likelihood method, and conduct the hypothesis test. Based on extensive numerical simulation, the power function is utilized to assess effectiveness of hypothesis testing. The simulation results show that lifetime performance index is good for determining whether the lifetime of the product reaches the criterion. Finally, a practical dataset is provided to give a demonstration for the procedures of lifetime performance evaluation.

The ventricular assist device (VAD) assists the patients with heart diseases for limited and prolonged periods. This device synchronizes with normal heart activities to help foster its performance. Consequently, its sensitive design requires high accuracy. The pumps are the essential part of every VAD which should operate in wide ranges of flow and pressure. As there are various types of VAD under different designs, it is neither practical nor plausible to experimentally/clinically investigate their performances. Therefore, in the concurrent study, a numerical study was carried out on four different generation prototypes of VAD pumps for reaching an optimum design. Using computational fluid dynamics (CFD) method, the software derived, showed and streamlined the flow field shear stress both inside the VAD and its blades. Furthermore, the vortices and flow rate-pressure curves were observed. The results showed that the curved blade pumps operate better compared to that of the straight blade types, concerning the provision of enough pressure and less damage to the red blood cells. The results have implications not only for comparing different types of VAD designs but also for understanding the resulted shear stresses and pressures as a result of the blade’s structure.

In order to study the three jump training and competition on knee joint impact damage degree, left knee joint of one healthy male athletes is used as the research object, a complete knee three-dimensional model was established based on the jumper’s knee CT scan and magnetic resonance imaging (MRI), including the femur, tibia, fibula, patella and knee major cartilage, ligaments. The multi-body dynamics analysis (MDA) and finite element analysis (FEA) method are used to calculate the three jump, jump starting, landing process of athletes knee joint impact, the state should change the status of stress, strain and displacement. The results show that in the three jump process, the load on the lateral contact area of the knee joint is the largest, the displacement is the largest, and it increases with the impact of jump and landing. This exacerbated the degree of wear and tear of the tibia, it tends to induce knee injury in athletes. The results show that the combination of finite element and MDA can better study the knee joint’s shock and vibration during the three-level jump training and competition, and these open up a new research method for the knee joint injury. It also provides a certain reference for the prevention and treatment of knee joint injury.

In order to reflect the vertical random vibration characteristics of railway vehicles more truly and effectively, this paper regards the human body as a single-degree-of-freedom system attached to the bottom of the carriage, and establishes a vertical dynamic model of railway vehicles by considering the influence of the coupling vibration effect between the passenger and the car body. The correctness of the model is verified by the real vehicle test. Then, the influence of the passengers on the vertical vibration characteristics of railway vehicles is analyzed, and the influence of the railway vehicle vibration on the vertical vibration characteristics of passengers is discussed in this paper. The research made in this paper can provide an effective model reference for the analysis of the vertical random vibration characteristics of railway vehicles and passengers, and for the optimization design of the suspension system parameters.

The multi-analysis modeling of a complex system is the act of building a family of models which allows to cover a large spectrum of analysis methods (such as simulation, formal methods, enactment,$\dots$) that can be performed to derive various properties of this system. The High-Level Language for Systems Specification (HiLLS) has recently been introduced as a graphical language for discrete event simulation, with potential for other types of analysis, like enactment for rapid system prototyping. HiLLS defines an automata language that also opens the way to formal verification. This paper provides the building blocks for such a feature. That way, a unique model can be used not only to perform both simulation and enactment experiments but also to allow the logical analysis of properties without running any experiment. Therefore, it saves from the effort of building three different analysis-specific models and the need to align them semantically.

In this paper, we develop two algorithms for solving linear and nonlinear fractional differential equations involving Caputo derivative. For designing new predictor–corrector (PC) schemes, we select the mesh points based on the two equal-height and equal-area distribution. Furthermore, the error bounds of PC schemes with uniform and equidistributing meshes are obtained. Finally, examples are constructed for illustrating the obtained PC schemes with uniform and equidistributing meshes. A comparative study is also presented.

In an LF/VLF transmission system, the performance of the antenna is of great importance to the entire system. Currently, the electret-based mechanical LF/VLF antenna uses mechanical movement to accelerate electret charges to produce LF/VLF electromagnetic waves, and the frequency of these electromagnetic waves is limited by the rotation speed of the actuating motor. Based on research that addressed the relationship between antenna structure and electromagnetic wave frequency, this paper — in order to increase the frequency of electromagnetic waves — alters the charge distribution mode of the mechanical antenna while keeping the motor’s rotational speed constant to realize an increase of transmission signal frequency. The effectiveness of this method was verified by model simulation.