| The paper mainly focuses on the analysis of FTIR spectra of toxic organic substance in the atmosphere and the establishment of diffusion models in the indoor air. Genetic Algorithm (GA) is used to quantitatively analyze strongly overlapped and undistinguishable spectra. It is also used to search pure spectra in spectra database by computer. Wavelet Transform (WT) technology of multiresolution feature extraction is studied to identify and quantitatively analyze remote sensing FTIR spectra by Mexican hat function. The signal is performed by continuous wavelet transform (CWT). Gaussian model is selected as a basic one to establish diffusion models in the indoor air. The attenuation relationships between integral concentrations and time of four pure subjects and one mixture are studied and modeled by mathematics. Three-dimensional models, which contain height, distance, time and concentration of a certain space point, are educed. The predicted values obtained from three-dimensional models are also compared with the real values.1. Genetic Algotithm (GA)How to identify strongly overlapped spectra has been a keystone in the chemometrics. With the rapid increase of the computer capability and calculating speed, the research on GA enters into a new course of development. It is widely used in many fields because it doesn' tdepend on grads information. Especially, it can deal with very complicated non-linear problem, which can not been solved by traditional method. GA simulates the evolution process of" the superior winning and the bad being eliminated" in nature and approaches the excellent results gradually. Five basic factors, i. e. parameter coding, determination of initial population, design of fitness function, design of heredity operation and the determination of convergence, are included in GA. Application of GA in the analysis of FTIR spectra is mainly discussed in the paper. The determination of the probability of crossover, probability of mutation, application of adaptive mutation, determination of fitness scale, discussion of convergent condition, quantitative analysis of mixed and undistinguishable FTIR spectra, identification of unknown system and spectrasearch on line are studied.The results indicate that GA can quantificationally analyze FTIR overlapped spectra successfully. It has several virtues, such as stochastic solution space; its function of global search; small relative errors and well non-linear characteristic. GA is also used as a good tool to search spectra. The search process is simple and the results are exact. It is suitable for spectra search, which have low concentrations and unsharp absorption peaks.Moreover, GA can identify quantificationally unknown FTIR spectra with the help of standard spectra database. Compared with ANN and PLS, it needn' t pretreat spectra data and can obtain a good effect for some spectra, which can not be analyzed by normal methods. Its calculating process is also simple. The accurate results can be obtained when the objective function is set up rationally and the data are properly performed by crossover and mutation operator.2. Wavelet Transform (WT)The spectra obtained from real-time detection in Remote Sensing FTIR spectrometer sometimes can not be identified because of the influence of the weather factors and the change of background. How to extract useful information from the complicated spectra is an attractive problem. WT technique is applied here to decompose FTIR spectra data, extract useful information and analyze FTIR spectra quantificationally for the purpose of spectra identification and analysis. Moreover, the relationship between WT and the baseline excursion of FTIR spectra is studied.The results indicate that WT can extract information from FTIR spectra to certain degree. Especially, it can determine the position accurately for pure or relatively outstanding spectra. At the same time, the noise in the spectra can be eliminated and the useful information is magnified.Furthermore, the relationship between WT...
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