This study constructs a comprehensive index to effectively judge the optimal number of topics in the LDA topic model. Based on the requirements for selecting the number of topics, a comprehensive judgment index of perplexity, isolation, stability, and coincidence is constructed to select the number of topics. This method provides four advantages to selecting the optimal number of topics: (1) good predictive ability, (2) high isolation between topics, (3) no duplicate topics, and (4) repeatability. First, we use three general datasets to compare our proposed method with existing methods, and the results show that the optimal topic number selection method has better selection results. Then, we collected the patent policies of various provinces and cities in China (excluding Hong Kong, Macao, and Taiwan) as datasets. By using the optimal topic number selection method proposed in this study, we can classify patent policies well.
With a longitudinal case study on the development of Liquid Crystal Display (LCD) technology of China Electronics (CEC) Panda, this study examined how Chinese firms build their technological innovation ecosystem (TIE). We explored the evolution and the driving mechanisms of TIE. The results of the study found: (1) The enterprise’s motivations for innovation and innovation efficiency can be improved when the core enterprise’s TIE is constructed. (2) The evolution of the enterprise’s TIE undergoes three stages: formation period, incubation period, and development period. (3) The interaction between the external factors from the environment and the internal factors from the agent drives the evolution of the TIE (4). Three types of driving modes develop, depending on the nature of the main factor affecting TIE development: extrapolation drive, hybrid drive, and internal drive.
the analytical moment method (MoM) is used to analyze the equivalence of a bond plate and an array of bond wires and some equations have been derived. To verify the validity of the proposed theory, several structures with different dimensions of bond wires have been analyzed and simulated up to 10 GHz. In case of different bond wire configurations, good agreements have been achieved between the theoretical analyses and simulation results. With the help of the proposed analytical method, the computing time of bond wires by commercial electromagnetic calculation software can be tremendously reduced.
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