Papers by Keyword: Iteration Algorithm

Abstract: In the long-term evolution (LTE) system, channel equalization makes compensation to restore the original signal, the paper puts forward iteration sphere decoding algorithm which combines traditional sphere decoding and the improved QR based on the conventional QR decomposition detection algorithm. It can effectively reduce the system complexity. At the same time, in QPSK and 16QAM, the simulation results show that the improved QR iterative sphere decoding algorithm performance is better with higher SNR in AWGN channel.

Abstract: Certain error exists in the data collected from multi-sensor network, which is caused by the external interference and defect of sensors. Thus, data fusion algorithm is applied in such monitoring to improve the reliability. In this paper, we propose a heterogeneous sensor data fusion algorithm for temperature monitoring in carbon fiber carbonization process. Through an improved adaptive weighting algorithm and iteration algorithm based on the average value, data from heterogeneous sensors are merged to obtain data closer to the real values. The feasibility of the method is verified in experiment.

Abstract: These methods that extract parameters of constitutive equations can be divided into three groups: direct search-based strategies, gradient-based methods and evolutionary algorithms. By analyzing these strategies, a new method based on iteration algorithm was proposed. To obtain parameters of JC and ZA model for Ti-6Al-4V, the error between prediction data and SHPB experiment data was set as objective function, then initial value was calculated using iteration algorithm. The effect of convergence rate and precision at various steps and experiment data was invested. The main advantage of the method are as follows：fast calculation; compatible with SHPB data and orthogonal cutting data; compatible with the decoupling and coupling constitutive equations. Finally, it has shown that the algorithm is stable, and acceptable results can be obtained.

Abstract: In a VAV system the static pressure can be reseted based on the change of load. At low load conditions the duct static pressure can be adjusted lower, that make VAV terminal air valves in large opening as far as possible.And lower fan outlet pressure can effectively reduce fan energy consumption. This paper presents a method using iterative algorithm to control the fan frequency. It can improve the dynamic quality of the control system. Satisfying the requirements under lower static pressure so as to achieve the purpose of energy-saving.

Abstract: This paper analyzes several important issues on the drill string system dynamics model and its numerical algorithm. Firstly, it introduces the commonly used numerical methods and contact algorithms, and analyzes the advantages and disadvantages of each method in detail. Secondly, it analyzes the application of explicit and implicit methods for the current stress iteration algorithm, and specifies the implicit algorithm should be used in the research of drill string system dynamics. This paper focuses on the research of damping model and bit-rock interaction model, solves the damping effect based on the theory of ocean wave mechanics, and establishes a simplified bit-rock interaction model. Finally, a virtual numerical simulation example shows that the method used in this paper can analyze the dynamic of drill string used in the 1,000-meter complex well bore. The research result of this paper has certain guiding meanings on the analysis of working behavior of extra-long pipe string in the complex well bore by using numerical methods in the oil field.