How to use experience and test result to make the best choice is a decision problem for a electric power company when deciding to build a reactor, and valuation networks is a new method for representing and solving Bayesian decision problems. This article used Valuation Networks to analyze the reactor problem of a given company, which valuation network representing and solving process is demonstrated in detail.
In view of the peak emergence of world oil and the prediction of China's energy demand and supply, the paper proposes that the development of China's oil industry should be based on domestic resources, which includes enhancing exploration and development of domestic oil-gas resources, building the conservation-minded society, realizing the multi-source strategy in energy development, etc. Meanwhile, great importance should be attached to exploiting overseas oil-gas resources and establishing the strategic reserves system for oil.
Because of the influence of rotary kiln supporting wheel's deflection on the contact area's contact stress, according to Hertz contact theory, the relative among deflection angle, the maximum contact stress and maximum contact stress ratio when supporting wheel is under parallel and deflective are derived. Furthermore, with the finite element method, the contact problems when supporting wheel is under parallel and the maximum deflection angle state are solved. Distribution of supporting parts'maximum contact stress and the equivalent stress and strain are obtained, and the dangerous and damageable place is learned. These analysis conclusions can provide effective theoretic guidance for rotary kiln axial adjusting and controlling.
This paper makes a calculation of the smoke evacuation volume in a certain Olympic gymnasium by using the smoke control formula from NFPA92B, and makes an optimization design of the smoke evacuation and ventilation system by using the Computational Fluid Dynamics (CFD) stimulation software. It also discusses the inner relationship among the mechanical smoke evacuation, the mechanical ventilation and natural ventilation as well as the influence of the mechanical ventilation volume on the smoke evacuation system in the Olympic gymnasium, which provides the theoretical basis for the optimization design of the smoke evacuation and ventilation system in the Olympic gymnasium.
Firstly, based on node equation method, a water distribution pipeline network steady flow mathematical model is established and is solved by using the Newton iteration method. Secondly, the mathematic model for transient flow set up by characteristic method can be used to forecast the harmful water hammer occurring in operation of the system, and to find the possible occurrence of the maximum (minimum) hydraulic pressure and their corresponding happened place. Sample shows that they are reliable models which have excellent computing efficiency and high order. The results are that these models can be applied to hydraulic balance calculation for city's water distribution pipeline network and provide the theoretic basis for designer to adopt measures preventing from water hammer.
During the operation process of largescale public project, financing risk is a main factor to the success of project. Based on the analysis of composition of finance and its connotation, using quantitative mode, this paper discussed the financing risk of large public project operation from three aspects: finance scale, construction time and return on the investment. Finally, it gave an illustration to prove the right of mathematic mode and put forward proposals for the increase of profit.
A novel endtoend data transmission scheme based on OFDM mechanism with good robustness against the RPE-LTP vocoder in GSM voice channel is proposed. According to the character of RPE-LTP vocoder, data are modulated to orthogonal lowfrequency sinusoidal carrier. In OFDM, the modulation is done by IFFT and the modulated signals are conformed to the time and frequency characters of RPELTP vocoder. The results of simulation show that the transmission bit rate of the proposed scheme reaches 2.4 kb/s，and the bit error rate of the scheme is lower than 0.3 %. This scheme provides a new approach for realtime secure voice data transmission over GSM system.
This Issue
Dec 2007, Volume 9 Issue 12