【正文】 nsor data to optimize the differentiated, or through the sensor optimized selection, . removal of the sensor, no contribution or a small contribution to improve the recognition capability, its purpose is to bring the group distance between the difference within a maximum while ensuring group minimum.Artificial Neural Network (ANN)The artificial neural network is a by imitate human or animal neural network behavioral characteristics, mathematical model of distributed parallel information processing. This network relies on a system of plex procedures, by adjusting the the internal large number of interconnected relationships between nodes, so as to achieve the purpose of processing information. ANN provided in advance a number of mutually corresponding input data output data, analysis, grasp the potential between the law, and ultimately with a new input data According to these laws, to derive output, this The learning process of analysis is called training. The aforementioned methods, ANN is usually considered to be a promising approach, and its features and benefits mainly in three aspects: with selflearning and adaptive function。s renal function, mental patients appreciate. The electronic nose in another medical application is the detection of cancer. The proposed electronic nose Italy and other noninvasive diagnosis of early cancer of the urinary tract。s Bloodhound. Domestic gas sensor has been developed rapidly in recent years, but pared to the overall foreign advanced countries quite different.Conclusion: Overall, most of the domestic and international electronic nose technology is still in the laboratory stage, even if there are still some problems in mercialization of pro。 detect ear, nose and throat infections reach up to 88% accuracy。 ground state phase sampling stage, holding phase and the recovery phase. Stage in the base state, the threeway solenoid valve is switched to the air passage, and a voltage signal of the sensor array to a horizontal baseline. To be a threeway solenoid valve is switched to the sample gas channel into the sampling stage, the sensor array response, a few seconds after the voltage signal value rose to a peak and then stabilized, to be close to equilibrium, the system enters the holding phase, threeway solenoid valve remains constant sample gas channel. The last to enter the recovery phase, threeway solenoid valve is switched back to the air channel, rapid decline in the response curve of the sensor array, until it is restored to the baseline position. The time value of the four stages of the testing process before the start of the test, you must first set on a PDA: the ground state time, sampling time, hold time and recovery time. Then Start mand, the system began to test issued by the PDA. Collection terminal after receiving the order, the internal microcontroller in accordance with the instructions, timer to control the time of the four stages. First, the microcontroller will control the heating voltage of DAC conditioning module output is used to heat the sensor array, and then control the signal voltage of the ADC module acquisition sensor array and choose to get the data saved to the memory module, or directly to the receiver by the wireless module feedback PDA to do the analysis and processing. After the data acquisition is pleted, PDA sends end mand, the system stops working. During the next round of testing is required before the PDA issue a reset mand to make the system cleared before a new round of tests. In addition, in the process of testing, you can issue mands through the PDA miniature air pump and threeway electronic valve control switch. After the test is stopped, the data of the sensor array can be read through the open instruction to obtain before and response curves.Statistical methods:Principal ponent analysis (PCA)Principal ponent analysis refers to several variables by linear transformation to elect a fewer number of important variables of multivariate statistical analysis method, also known as principal ponent analysis。畢業(yè)設(shè)計(jì)（論文）報(bào)告題 目 基于單片機(jī)的 電子換號牌的設(shè)計(jì) 系 別 專 業(yè) 班 級 學(xué)生姓名 學(xué) 號 指導(dǎo)教師 2013年 4 月25無錫科技職業(yè)學(xué)院科技論文 The application of electronic noseThe application of electronic noseAbstract: positive human olfactory organ is a plex physiological reaction. Nature kind of odor tens of thousands, even professionals specializing in odor identification work is often recognition errors.Keywords: electronic nose puter technology developed olfactory organs physiological reaction Customs security monitoring neural networks odor sensor identification infrared sensorIntroduction: The electronic nose developed a hightech products is simulated animal olfactory organ, scientists are still not all clear principle of the animal39。 3) cleaning the sensor: measured after the sample is finished, use of alcohol vapor flush . The sensor surface of the active material, the odor removal measured Bi mixture. In enter new measurement prior to the next round, the sensor still implement initialization (that is, between the work again, each sensor are required dry air or some other reference gas cleaning to meet the benchmarks). The measured odor effect of time is called the response time and the purge process and the reference gas role of the sensor array used in the initialization process time is called the recovery time.The electronic nose system consists of two parts: information acquisition the terminal (Acquisition terminal) and information processing terminal (processing terminal). 1) collection terminal is responsible for collecting the signal voltage of the MOS gas sensor array processing terminal via a handheld puter (PDA) to plete the data analysis and processing. Two terminal data exchanged by the two wireless module. Collection terminal consists of three major ponents: sampling systems, electrical systems, as well as the sensor