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Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aiming at the harmonic problem of the distributed generation (DG) connected with power distribution network, the capacity and installation of DG in power distribution network were studied. The DG penetration levels were calculated by artificial bee colony(ABC) algorithm in compliance with the limitation of harmonics in GB/T14549-1993. The impact of harmonic injection on power distribution network caused by capacity and installation of DG was analyzed; The limitations in compliance with the requirements of voltage regulation and harmonic distortion were determined; The DG penetration level was calculated complying with the limitation of harmonics by ABC algorithm. The results indicate that, the method for calculating DG penetration level can achieve the optimization goal, satisfy the constraint voltage adjustment and harmonic distortion limits, maximize access power distributed power, and provide the reference for the distributed power supply the best integrationpoint. [ABSTRACT FROM AUTHOR]

Aiming at the problem of voltage reduction and voltage distortion due to the extensive use of inductive loads, and some shortcomings of existing reactive power compensation devices, a new AC--AC chopper based var compensator was proposed. The basic principles, compensation characteristics and topolog of the improved Buck-Boost AC--AC chopper based var compensator were described, the mathe-matical model of improved Buck-Boost based on state-space equation was established, the relationship between duty ratio and compensation current was derived. The instantaneous reactive power theory and direct current control method were adopted to build a Matlab model. The results indicate that the real-time compensation of reactive power in grid side can be realized by this var compensator based on a direct controlled Buck-Boost AC--AC chopper, it has potential application value. [ABSTRACT FROM AUTHOR]

When collecting the QR code image,the inclined or geometric distortion often occured. To solve this problem, a correction method combined the QR code feature, image rotation and image maps was proposed. This method, firstly, used the position detection patterns to detect tilt aberration after conventional image pre-processing and run length encoding; Secondly, selected the appropriate method by tilt aberration to correct the image; Thirdly, used grid and statistical methods to extract information and complete the decoding. The results showed that the method was simple and had a high rate of recognition. The computation of floating-point was small,so it could be used in embedded system. [ABSTRACT FROM AUTHOR]

The end-to-end distortion provides the gist of optimized strategy in video codec and transmission. This paper analyzes the end-to-end distortion system combined with error concealment. Then the coefficient of error propagation between frames is estimated by employing structural similarity index measurement (SSIM) based on the analysis results. Finally an improved end-to-end distortion estimation model is proposed. The proposed model could estimate the distortion with the characteristic of the original video sequence, parameters of encoding and transmission and no detailed encoding information is needed. Furthermore, with the information of previous real distortion feedback through transmission channel, the proposed model could estimate the distortion more precisely. The simulation results show that the proposed model could estimate the distortion very well with and without the feedback information. [ABSTRACT FROM AUTHOR]

This paper studied the optimum sensor node density for one-and two-dimensional wireless sensor networks (WSNs) with spatial source correlation. The WSN attempted to reconstruct a spatially correlated signal field by collecting the location-dependent measurements from the distributed sensor nodes. It designed the WSN to minimize the mean square error (MSE) distortion between the original and the reconstructed signals under the constraint of a fixed power per unit area. It investigated the impacts of node density and spatial data correlation on the network performance for both small networks and large networks. It quantitatively identified the interactions among the various network parameters and their impacts on the system performance with exact analytical expressions. The results provide guidelines on the design of practical WSN. [ABSTRACT FROM AUTHOR]

The characteristics of earthquake response for long-period structures, and a few shortages existing in the response spectrum of China code for seismic design of buildings are analyzed. It can be clearly found that an artificial modification to response spectrum can result in the distortion of ground motion characteristics. The revision to the longperiod segment in the response spectrum of China code can cause the change in the characteristics of ground motions, which results in an abnormal representation of power spectrum corresponding to acceleration spectrum. The analysis results show that the calculated displacements of long-period structures under earthquake action are over estimated. Minimum story seismic shear coefficient described in the specification is only related to maximal earthquake influence coefficient (αmax), but is not related to site classification, which is in conflict with the general rule that the earthquake responses of a structure at the soft-soil site are larger than those of a structure at the hard-soil site. According to the pseudo spectrum relations among acceleration spectrum, pseudo-velocity spectrum and displacement spectrum, a response spectrum pattern with longer-period segment (T is approximately extended to 10 s) is proposed, which can provide a reference to specification revision. Engineering cases show that calculating the displacement of structure according to the proposed response spectrum is feasible. [ABSTRACT FROM AUTHOR]

Based on the reverse design method of hypersonic inlet curved compression surface from the assigned pressure distribution, the effect of design parameters on the compression performance such as shock length ratio, pressure ratio, total-pressure recovery, distortion and drag coefficient is investigated, using numerical simulation according orthogonal design. The results show that, curved compression surface designed with this method can exactly meet the expected pressure distribution, and the pressure gradient G2 and G3 on the middle section of the curve have remarkable influence on compression performance. [ABSTRACT FROM AUTHOR]

Based on digital micro mirror device (DMD), an innovative well-athermalized projection optical system with long exit entrance distance and big exit entrance aperture for infrared target simulator was designed. The exit pupil distance of the system could reach 1 000 mm, the entrance pupil aperture is $120 mm, and the distortion is better than 1% . In order to simulate a target of -40 t, the projection optical system needs to work in the cooled environment, thus the optical system needs to be athermalized. The projection optical system uses three kinds of materials and four lenses. In the range of - 40 °C ~ 20 °C, the maximum defocus amount is less than the system' s the depth of focus. Analysis shows that this system could work stably at -40 °C ~ 20 °C, with MTF of all fields being better than 0. 4 at 16 lp/ mm. RMS is smaller than the size of micromirror, and the distortion is better than 1% . The system has a long exit pupil distant, meanwhile it is well athermailized. [ABSTRACT FROM AUTHOR]

Detection of architectural distortion (AD) in mammograms is one of important approaches in breast cancer diagnosis. For solving the problem of high false positives in the detection of AD, a novel method is proposed based on the methodology of systems engineering. In the proposed method, the spiculation similarity convergence index (SSCI) is computed to enhance radiating spiculations. After that, the three-ring-region temple and the convergence threshold are used to obtain suspicious regions. Finally, support vector machine (SVM) is utilized to classify the suspicious regions into AD and normal tissues. The proposed method is evaluated on 64 mammograms from the mammographic image analysis society (Mini-MIAS) and 50 mammograms from the breast cancer of Peking University People's Hospital. The results show that the proposed detection method can decrease FPs significantly, and can be applied to mammograms of both oriental and occidental women. [ABSTRACT FROM AUTHOR]

As the TOA ranging error was always corrupted by the direct path blockage and excess delay in complicated indoor environments, the NLOS ranging error due to IR-UWB through wall propagation was modeled by dividing it into two parts: the geometrical error caused by the pulse transmitted through wall, and the peak biased error caused by the pulse waveform distortion due to frequency dependence of huge bandwidth. The theoretical geometrical error bound was derived from transceiver distance, wall thickness and materials. The IR-UWB through wall propagation was modeled using sub-band method, and the peak biased errors were investigated through the waveform distortion of IR-UWB signal propagated in different wall structures. The simulation results show that the geometrical error was mainly determined by the obstacles parameters and the peak biased errors caused by IR-UWB waveform distortions were within the distance resolution of IR-UWB signal. [ABSTRACT FROM AUTHOR]

Due to the development of the image processing technology, it made higher requests for image and video evaluation, and blur metric could reflect the objective quality of image and video more accurately. In order to improve the accuracy of objective evaluation of image and video, this paper studied the blur and proposed an improved algorithm based on full reference blur ratio. It first used edge detection algorithm to get the vertical edge image and calculate blur value of every frame of video, then marked the blur value in the coordinate of the original and distortion video, as usual, there were three kinds of distributions: dot, line and scatter, at last, used three solutions to match the distributions: slop of mean, linear regression and minimum enclosing circle, the result of experiment shows that these three kinds of solutions can give higher reference between subjective evaluation and objective evaluation of image and video. [ABSTRACT FROM AUTHOR]