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1.
This paper describes the methodology through which a fuzzy expert system capable of computing maximum A-weighed noise level (LA,max) for the Tehran-Karaj commuter train is developed, tested, tuned and validated on the basis of the 50 measurements from five locations at distances of 25 m, 35 m, 45 m, 55 m, and 65 m from the centre of the track and at a height of 1.5 m. The expert system is initially developed, tested and tuned through the judgements made on the premise of the samples taken at the distances of 25, 45 and 65 m. The conducted hypothesis test, the non-parametric two-related samples Wilcoxon test, for this stage indicates satisfactory results. Eventually the developed expert system is validated for the measurements related to the distances of 35 and 55 m through carrying out the non-parametric two-independent samples Kolmogorov-Smirnov test.  相似文献   

2.
This paper presents mathematical logarithmic, statistical linear regression, and neural models capable of predicting maximum A-weighed noise level (LA,max) for the Tehran-Karaj express train. The models have been developed upon the basis of the measurements from sampling locations at distances of 25 m, 45 m, and 65 m from the centreline of the track and at a height of 1.5 m. In the next step, the predictive capability of the models have been tested on the data associated with the sampling locations, situated, respectively at distances of 35 and 55 m from the centreline of the track at a height of 1.5 m. The non-parametric tests i.e. two-related samples Wilcoxon, and two-independent samples Kolmogorov-Smirnov, carried out, respectively for training and testing steps, indicate satisfactory results. In the final step the non-parametric k-related samples Friedman test detects no significant differences amongst the absolute testing set error of the models.  相似文献   

3.
The subject of this paper is the long distance propagation of train noise. The sound exposure level of train noise LAE was measured. To describe the results of measurements, a semi-analytical model was used. It takes into account the wave-front divergence, air absorption, ground effect, and the turbulence destroying the coherent nature of the ground effect. The model contains three adjustable parameters that must be estimated at the site. To verify the model, we performed measurements of LAE at the distance D = 450 m from the train track center. The difference between the calculated and measured mean values of LAE equals 1.3 dB.  相似文献   

4.
The structural and magnetic properties of ∼12 nm thick FePt thin films grown on Si substrates annealed using a 1064 nm wavelength laser with a 10 ms pulse have been examined. The A1 to L10 ordering phase transformation was confirmed by electron and X-ray diffraction. An order parameter near 50% and a maximum coercivity of 12 kOe were obtained with laser energy densities of 25-32 J/cm2. Grain growth, quantified by dark field transmission electron microscopy, occurred during chemical ordering at the laser pulse widths studied.  相似文献   

5.
A high-resolution (0.002 cm−1) infrared absorption spectrum of methylene fluoride-d2 (CD2F2) of the lowest fundamental mode ν4 in the region from 460 to 610 cm−1 has been measured on a Bruker IFS 120-HR Fourier transform infrared spectrometer. More than 3500 transitions have been assigned in this B-type band centered at 521.9 cm−1. The data have been combined with upper state pure rotational measurements in a weighted least-squares fit to obtain molecular constants for the upper state resulting in an overall standard deviation of 0.00018 cm−1. Accurate value for the band origin (521.9578036 cm−1) has been obtained and inclusion of transitions with very high J (?60) and Ka (?34) values has resulted in improved precision for sextic centrifugal distortion constants, in particular DK, HKJ, and HK.  相似文献   

6.
In a discharged supersonic jet of Cl2, transitions of the D′ 2g(3P2)-A3Π(2u) system for 35Cl2 were observed directly by laser induced fluorescence spectroscopy. By a discharge in Cl2, the Cl2 molecules were populated into the A′ state, which is a metastable and optically forbidden state, from the state. An ultraviolet laser radiation excites the molecules to the D′ ion-pair state. A set of Dunham parameters for the A′ state is determined from a global least-squares fitting for 59 vibronic bands with v″ = 0-7. In the fitting, the previously reported data, T(v) and B(v) for the v = 14 and 15 bands of the A′ state [T. Ishiwata, A. Ishiguro, K. Obi, J. Mol. Spectrosc. 147 (1991) 300-320], were included. Y00 = 57295.723(5) cm−1 of the D′ state [J.-H. Si, T. Ishiwata, K. Obi, J. Mol. Spectrosc. 147 (1991) 334-345] was also included in the global fitting in order to determine the absolute position of the A′ state. The determined parameters of the A′ state are Y00 = 17171.506(14), Y10 = 255.915(85), Y20 = −4.465(70), Y30 = −8.7(23) × 10−2, Y40 = 6.3(35) × 10−3, Y50 = −4.9(26) × 10−4, Y60 = 1.43(69) × 10−5, Y01 = 0.16282(15), Y11 = −2.363(68) × 10−3, Y21 = −5.01(93) × 10−5, and Y31 = −3.01(36) × 10−6 (in cm−1 and one standard deviations of the fit in parentheses). The absolute position of the A′ state is determined with good accuracy.  相似文献   

7.
The rotational spectra of the ground vibrational state and the ν9 = 1 torsional state have been reinvestigated and accurate spectroscopic constants have been determined. The torsional frequency, ν9 = 70(15) cm−1, has been determined by relative intensity measurements. The assignment of the infrared spectrum has been slightly revised and an accurate harmonic force field has been calculated. The equilibrium structure has been determined using different, complementary methods: experimental, semi-experimental and ab initio, leading to r(NN) = 1.870(2) Å, in particular.  相似文献   

8.
A field study has been carried out in urban Assiut city, Egypt. The goals of this study are: (1) to carry out measurements to evaluate road traffic noise levels, (2) to determine if these levels exceeds permissible levels, (3) to examine people’s attitudes towards road traffic noise, (4) to ascertain the relationship between road traffic noise levels and degree of annoyance. The measurements indicate that traffic noise noise levels are higher than those set by Egyptian noise standards and policy to protect public health and welfare in residential areas: equivalent continuous A - weighted sound pressure levels (LA eq) = 80 dB and higher were recorded, while maximum permissible level is 65 dB. There is a strong relationship between road traffic noise levels and percentage of highly annoyed respondents. Higher road traffic noise levels mean that the percentage of respondents who feel highly annoyed is also increased.  相似文献   

9.
L1 regularization and Lp regularization are proposed for processing recovered images based on compressed sensing (CS). L1 regularization can be solved as a convex optimization problem but is less sparse than Lp (0 < p < 1). Lp regularization is sparser than L1 regularization but is more difficult to solve. This paper proposes joint L1/Lp (0 < p < 1) regularization, which combines Lp regularization and L1 regularization. This joint regularization is applied to recover video of remote sensing based on CS. Joint regularization is sparser than L1 regularization but is as easy to solve as L1 regularization. A linearized Bregman reweighted iteration algorithm is proposed to solve the joint L1/Lp regularization problem. The performance and capabilities of the linearized Bregman algorithm and linearized Bregman reweighted algorithm for solving the joint L1/Lp regularization model are analyzed and compared through numerical simulations.  相似文献   

10.
The magnetocaloric properties of melt-spun Gd-B alloys were examined with the aim to explore their potential application as magnetic refrigerants near room temperature. A series of Gd100−xBx (x=0, 5, 10, 15, and 20 at%) alloys were prepared by melt spinning. With the decrease in Gd/B ratio, Curie temperature (TC) remains constant at ∼293 K, and saturation magnetization, at 275 K, decreases from ∼100 to ∼78 emu/g. Negligible magnetic hysteresis was observed in these alloys. The peak value of magnetic entropy change, (−ΔSM)max, decreased from ∼9.9 J/kg K (0-5 T) and ∼5.5 J/kg K (0-2 T) for melt-spun Gd to ∼7.7 J/kg K (0-5 T) and ∼4.0 J/kg K (0-2 T), respectively for melt-spun Gd85B15 and Gd80B20 alloys. Similarly, the refrigeration capacity (q) decreased monotonously from ∼430 J/kg (0-5 T) for melt-spun Gd to ∼330 J/kg (0-5 T) for melt-spun Gd80B20 alloy. The near room temperature magnetocaloric properties of melt-spun Gd100−xBx (0≤x≤20) alloys were found to be comparable to few first-order transition based magnetic refrigerants.  相似文献   

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