Applied Mechanics and Materials Vols. 55-57

Abstract: On the basis of the brief overview of principles of the gas detection system, this paper has analyzed the characteristics, structure and identification theory to explain the method of gas detection based on an artificial neural network. And it has analyzed and researched gas detection system based on neural network and thus solved the problems such as cross-sensitiveness in present gas sensor. The results show that the gas sensor array "cross-sensitive" issue can be effectively solved through the combination of the pattern recognition of artificial neural network and the gas sensor array technology, which accordingly realizes qualitative identification for different gases and has broad application prospects.

Abstract: The paper focus on dynamic bayesian network (DBN) inference system and its application on the natural gas transmission and distribution network for the system fault diagnosis which is including time restriction (that is the earliest start time and the latest end time) for task. DBN is a graphic model which can describe the relationships between variable data, and used for reasoning. After we research the basic model of DBN, and the maximum depend algorithm is improved which which can increase the feasibility of natural gas transmission and distribution network system. we can see the new model is more accuracy than the traditional technical fault diagnosis clearly. Also, simulation result can verify the design of DBN is effectively and valuable.

Abstract: There are very complicated nonlinear relations between input value and presentation color of digital prepress devices, as well as in the gamut mapping among different devices. Not all the relations can be described by linear model properly. In recent years, neural network and black box theory are introduced to describe the relations. In this research, the printer gamut is divided into micro space sections, a relative colorimetric rending mapping method is proposed based on BP neural network theory to complete the gamut mapping from monitor gamut to color printer. Experimental results show that the model reduces the color error of color blocks between the two devices, and the color rendering method can be used for gamut mapping of image with less continuous tone.

Abstract: The paper introduces the design of the portable intelligent monitoring system based on Bluetooth sensors, the system is made up of three main subsystems: physical state data acquisition system based on Bluetooth sensor, wireless communication terminal, and hospital monitoring center. The physical state data acquisition system monitors the main physical parameters of human being real-time and sends to wireless communication terminal by Bluetooth, wireless communication terminal receives the physical parameters and recognizes the physical state of human being with intelligent data fusion algorithm. The abnormal data will trigger the communication terminal send an alarm message to hospital monitoring center, and the abnormal data will be transmitted to hospital, and then the doctor can diagnose the condition of the human being.

Abstract: According to the requirement of vehicle dynamics' accurate simulation and control, the paper studies the tyre regression algorithm based on the tyre bench test data. Due to the tyre test's characters of few data and big discreteness, the method of least squares support vector regression (LSSVM), which has the superiority of structural risk minimization, was selected to find the nonlinear mapping between input and output variables of tyre test data. Removing data gross error and improving the sparsification measures were taken to increase the calculation real time of standard LSSVM algorithm. An adaptive genetic algorithm (AGA) with global searching ability was chosen to determine the kernel function and regularization parameters of LSSVM. Test data set’s regression root mean square error (RMSE) was taken as the fitness function of AGA. Finally, the tyre test data under steady state sideslip condition was provided to simulate and verify the effectiveness of tyre regression algorithm, according to the precision and real time requirements of vehicle dynamic simulation and control.

Abstract: Based on the classical electrostatic theory, the distributions of potential and electrical field at the apex of the carbon nanotubes (CNTs), both in normal-gate type triode structure and under-gate type triode structure, were simulated and calculated respectively. The gate electrode's position and gate aperture's effect on CNTs' field emission characteristics were analyzed. The results indicate that under-gate structure, compared with normal-gate structure, has better field emission performance and lower threshold voltage. Both the gate aperture and the distance between gate electrode and CNTs' apex have crucial effect on field enhancement factors of normal-gate structure and under-gate structure.

Abstract: Promoting the central rise of China is one of the important development strategies for our country. It is also the objective needs for East-West Fusion and North-South butt joint, and for promoting regional economic development. This article used linear regression and other econometric methods, regarded the average gross domestic product (GDP) of the Six central provinces (Henan, Shanxi, Hunan, Hubei, Anhui and Jiangxi) as the explained variable to represent the average development level of economy, identified the average value of freight turnover in the six central provinces as explanatory variable to represent the average development level of the logistics industry in the six central provinces; and quantitative analyzed the relationship between the average GDP and the average value of freight turnover of the six central provinces with Eviews software, moreover, put some relevant recommendations for the future rapid development of economy in the Six central provinces.

Abstract: This paper deals with an approach to the approximation measurement on the enterprise information system (EIS) based on its formal representation. To explore the approximation between modules in EISs and lay foundation for the reconfiguration of EIS, an approximation measurement on the object-based knowledge mesh (OKM) and information transfer relationship mesh (ITRM) corresponding to EIS is proposed. Firstly, based on the definitions of the approximation on atom knowledge point (KP) and relationships, the approximation measurement on OKM with only atom KPs is proposed. Then, the approximation measurement on ITRM is also given, with the steps of the approximation measurement on EIS presented in detail as well. Finally, based upon the above, the approximation measurement on EISs is illustrated by an example to show the application of the proposed method.

Abstract: Closed loop converters are strongly nonlinear system. Dynamic behavior is difficult to investigate by traditional approach. For some PWM controlled converters, low frequency ripple may occur in the output voltage and results in unsteadiness to the system. In this paper buck converter is taken as an example to investigate the stability feature. A delay in the feedback loop is related with stability closely, so the converters with delay and without delay are analyzed in detail, respectively. The second-order differential equation for output voltage profile is established. Characteristic equations are deduced from the differential equations. Based on Hurwitz Stability Criterion, stability requirement is derived from characteristic equations. It is shown that converters without delay in the feedback loop are steady. On the other hand converters with delay in feedback loop may produce low frequency ripple in some cases. Regulating parameters can avoid the low frequency ripple phenomenon. The frequency and amplitude of the low frequency ripple voltage are determined by using zero-pole analysis method. The proposed approach is verified by simulation and experiment. The simulation and experiment results demonstrate that the analysis is correct.

Abstract: Parameterized model of principal-agent incentive mechanism has been designed through mathematical analysis in this paper. The analysis of monitoring mechanism is introduced in the principal-agent incentive mechanism, which extends the theoretical framework of incentives. The results show that: monitoring mechanisms and incentive mechanisms are relevant and the interaction between them has a substitution effect. They can encourage or induce an agent to work hard. Therefore, incentive mechanisms and monitoring mechanisms should be taken into account in the process of compensation contract formation. The introduction of monitoring mechanisms not only has some innovations in theory, but also has great value in practice.