Maohua Zhong

Study in performance analysis of China Urban Emergency Response System based on Petri net.

Abstract Urban Emergency Response System (UERS) is a modernization symbol of a city. With acceleration of urbanization process and constant expansion of city size in China, China cities must respond to various emergencies timely and effectively to satisfy urban residents’ needs for public security. In recent years, many China cities made trials and efforts in setting up and improving the UERS. At the same time, the China government began to build Emergency Response Systems (ERS) in some cities to deal with various possible emergencies. In this paper, using Petri net (PN), we study the performance of China typical UERS and establish its PN model for performance analysis. Based on the Markov chain (MC) of the model, the performance of China typical UERS is analyzed. Results from our simulation are in conformity with practical operation of China current UERS.

Two-color optical charge-coupled-device–based pyrometer using a two-peak filter

A two-color optical charge-coupled-device (CCD)-based pyrometer was developed using a multipeak interference filter with a color CCD sensor to measure multicolor signals with specified wavelengths. The effective and simple method adjusts the fixed spectrum response characteristics of a color CCD to allow improved temperature measurements. This pyrometer system not only has the advantage of traditional two-color (two-wavelength) pyrometry, but also overcomes the restrictions of color CCDs that can only be applied in waveband measurements. The measurement performance of the system using a two-peak filter (λ(1)=643 nm, λ(2)=564 nm) was evaluated by blackbody experiments. The results show that the low temperature detection limit is increased about 200 K with an increase in the sensitivity of the measured signals compared with the original system without two-peak filter [Fu, et al., Opt. Laser Technol. 42, 586 (2010)]. And the effective temperature range is also increased when T > 1233 K. The measured ratio C(R)/C(G) is monotonically relative to the temperature, which simplifies the measurements. The temperature sensitivity of 2.49 is larger and more uniform than the temperature sensitivity of 1.36 in the previous original system. Thus, the measurement performance of the new system is greatly improved. Finally, as an application, the surface temperature distribution of stainless steel sample in hot environments was determined by this new CCD-based pyrometer. The results agree well with the spectrometer-based results and further verify the applicability of the new system.

The set-up of a vision pyrometer

The paper presents a new radiation pyrometer, a vision pyrometric device based on a commercial digital colour camera and SUNPRO software, which converts the calibrated commercial digital colour camera into a scientific instrument for temperature measurement. We introduce the calibration experiments and the principle of this vision pyrometer, and the application of the vision pyrometer is illustrated in the specific examples. The analysis shows that the vision pyrometer established in this paper is convenient and promising and will be able to realize real-time measurements of two-dimensional temperature fields.

Improvements to the three-color optical CCD-based pyrometer system

We put forward an improved three-color measurement scheme with a color CCD sensor using the combination of effective wavelengths and blackbody calibrations. The process of effective wavelengths realizes the separation of the emissivity function from the measurement integral equation. This improved method not only effectively avoids errors arising from the traditional process adopting the basic wavelengths, but also simplifies the complex integral calculations. For a blackbody or graybody, the measurement performance of the pyrometer was experimentally investigated from the point of the temperature sensitivity. The results show that narrowing the spectrum bandwidth with different bandpass spectral filters may improve the temperature sensitivities. The spectrum adjustment not only makes the linear emissivity more suitable in the narrower waveband, but also reduces the numerical uncertainty of the effective wavelengths. For nongray objects, the effects of the numerical uncertainty of the effective wavelengths to measurements were quantificationally evaluated at different measurement conditions (different temperatures, emissivities, and spectrums). The results indicate that the reference values of 584, 555, and 511nm or 607, 560, and 506nm of the effective wavelengths are reasonable for the present system with the modified spectral response using Filter 1 or Filter 2. The maximum calculation errors arising from the reference effective wavelengths are less than 1.6%. In this paper, the technical realization steps of the improved method are also described. The measurement experiments of a metal sample in hot environments were carried out to further verify the applicability of this improved CCD-based pyrometer. The results agreed well with the spectrometer-based results.

The theoretical prediction analyses of the measurement range for multi-band pyrometry

In the applications of multi-band pyrometry, the coupled correlation of multi-channel measurement information is a distinct characteristic. Considering this point, in order to realize the non-distortion and effective measurement, the theoretical differentiation formula of the measurement range is put forward in this paper. It may estimate not only the temperature range, but also the emissivity parameter range for the specific measured surface. Then, the corresponding simulation results are given. For an exploited multi-band pyrometer, the theoretical estimations are verified through blackbody measurement experiments. Therefore, the analyses in the paper provide the necessary theoretical supports for the design and application of a multi-band pyrometer.

The measurement coordinates for multi-band pyrometry

The purpose of this paper is to investigate the distribution characteristics of temperature and emissivity in the applications of multi-band pyrometry. We establish the concept of the measurement coordinates, including the temperature coordinate axis and emissivity coordinate axis. Through numerical simulations, we present the corresponding results. The discussions not only provide a simplified and effective expression of the solutions of multi-band pyrometry, but are also helpful to design or optimize a multi-band radiation pyrometer by investigating beforehand the distribution rules of temperature and emissivity in the measurement coordinates.