Passive optical networks are widely used as a promising solution for future access networks. Currently, the bandwidth is still increasing which means the current copper networks are not able to transfer new services s...
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Passive optical networks are widely used as a promising solution for future access networks. Currently, the bandwidth is still increasing which means the current copper networks are not able to transfer new services such as 4K video, live streaming, etc. In other words, they reached their capacity limit. The passive optical networks rely on point-to-multipoint technology. That means each customer uses a share medium by time slots. Each time slot exactly specifies who and when is able to transfer data. In general, this control mechanism is implemented in the optical network unit by worst transmission convergence layer. On the other hand, there are cases when the optical network unit (it is called rogue optical network unit) does not follow instructions provided by the optical line termination, for example, if an attacker modifies a firm ware of the end unit and/or when the control protocol is not loaded properly inside optical network unit. In worst case, the optical network unit transmits data in a continual mode (other optical network units cannot send data). The standard defines finding of the rogue optical network unit but it does not specify how the rogue optical network unit should be allocated because the frames of the rogue optical network unit do not contain the proper parameters. We realized a measurement in a real network with the rogue optical network unit and then we analyzed the captured data. A new algorithm for the rogue optical network unit allocation is presented. We do not consider any modification of the transmission convergence layer in gigabit passive optical networks.
In this paper we present a method to generate high-quality hard shadows in real-time based on geometry shadow map. The method focuses on addressing the aliasing artifacts due to the large number of overlapping primiti...
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ISBN:
(纸本)9789811015366;9789811015359
In this paper we present a method to generate high-quality hard shadows in real-time based on geometry shadow map. The method focuses on addressing the aliasing artifacts due to the large number of overlapping primitives which cannot be stored sufficiently and yields error of depth reconstruction. We call it Covered Primitives Parallel detection algorithm (CPPD). In CPPD, a parallel detection algorithm according to the texel edges is proposed without increasing storage of different triangles. Experiments show that CPPD algorithm can improve the accuracy of depth reconstruction and reduce the jagged shadows effectively.
The paper deals with an algorithm for detection of a broadband signal received from a multiple-unit source against the background with architecturally-like clutters that differ by location and additive space-uncorrela...
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ISBN:
(纸本)9781509040698
The paper deals with an algorithm for detection of a broadband signal received from a multiple-unit source against the background with architecturally-like clutters that differ by location and additive space-uncorrelated noise. It is shown that the optimal detection algorithm represents the weight processing in the "ray space" of the transformed vector of observed data and does not demand access of any large matrix. A maximum likelihood ratio is chosen as the optimality criterion. After determining the inverse of the correlation function, expression for the optimal weight function is obtained. The design ratios for determination of detection characteristics under the Gaussian statistics of signals and clutters are given. The results confirm the property of the suggested algorithm: at low signal/noise ratios, efficiency of point targets detection is better, and at the large ratios the distributed targets are better detected.
Pavement crack detection plays a vital part in highway maintenance and management. It is difficult to detect cracks effectively and accurately through ideal detecting algorithm. This paper improves the pavement crack ...
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ISBN:
(纸本)9781509007684
Pavement crack detection plays a vital part in highway maintenance and management. It is difficult to detect cracks effectively and accurately through ideal detecting algorithm. This paper improves the pavement crack image processing algorithm from the angle of grey level transformation, median filter and image intensification according to the characteristics of the pavement crack image. Based on defect image segmentation and image edge detection, results show that the proposed detection method can effectively remove the isolated noise point, smooth the edge and improve the segmentation accuracy.
In order to improve the protection reliability of asymmetric fault, real-time and accurate sequence current is very indispensable. This paper proposes a simple and effective method based on park transformation theory ...
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ISBN:
(纸本)9781509030712
In order to improve the protection reliability of asymmetric fault, real-time and accurate sequence current is very indispensable. This paper proposes a simple and effective method based on park transformation theory and conducts research on positive-current, negative-current and zero-sequence current. Moreover, the harmonic currents, active current and reactive current can be calculated. Through simulation experiment, the validity and feasibility of paper method have been confirmed.
The working status of huge rotating mechanical equipment can be judged with the method of detection and processing its acoustics. It is analyzed that the variation of the sound reflected the variation of the material ...
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ISBN:
(纸本)9781467398596
The working status of huge rotating mechanical equipment can be judged with the method of detection and processing its acoustics. It is analyzed that the variation of the sound reflected the variation of the material percentage in the equipment. The sound caused by different material percentage is collected and analyzed in time and frequency domain in this paper. A practical material percentage detection algorithm is proposed. The frequency spectrum of quantitative analysis for the material percentage is determined. The procedure of algorithm design includes calibration and quantitative detection. The field detection results show its effectiveness.
Passive optical networks are widely used as a promising solution for future access networks. Currently, the bandwidth is still increasing which means the current copper networks are not able to transfer new services s...
详细信息
Passive optical networks are widely used as a promising solution for future access networks. Currently, the bandwidth is still increasing which means the current copper networks are not able to transfer new services such as 4K video, live streaming, etc. In other words, they reached their capacity limit. The passive optical networks rely on point-to-multipoint technology. That means each customer uses a share medium by time slots. Each time slot exactly specifies who and when is able to transfer data. In general, this control mechanism is implemented in the optical network unit by worst transmission convergence layer. On the other hand, there are cases when the optical network unit (it is called rogue optical network unit) does not follow instructions provided by the optical line termination, for example, if an attacker modifies a firm ware of the end unit and/or when the control protocol is not loaded properly inside optical network unit. In worst case, the optical network unit transmits data in a continual mode (other optical network units cannot send data). The standard defines finding of the rogue optical network unit but it does not specify how the rogue optical network unit should be allocated because the frames of the rogue optical network unit do not contain the proper parameters. We realized a measurement in a real network with the rogue optical network unit and then we analyzed the captured data. A new algorithm for the rogue optical network unit allocation is presented. We do not consider any modification of the transmission convergence layer in gigabit passive optical networks.
The performance of mode division multiplexing (MDM) systems is limited by mode-dependent loss (MDL), which seriously deteriorates the unitarity of the transmission matrix, making the traditional detection algorithms i...
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The performance of mode division multiplexing (MDM) systems is limited by mode-dependent loss (MDL), which seriously deteriorates the unitarity of the transmission matrix, making the traditional detection algorithms ineffective. In order to mitigate the effect of MDL in MDM transmission and improve the efficiency of digital signal processing at the receiver, a novel coordinate descent (CD)-based box-constrained detection algorithm using adaptive moment estimate (CDbox-Adam) is proposed. In the process of each coordinate update for the CDbox detection algorithm, the adaptive moment estimation (Adam) method adaptively updates the step size for different parameters from the first moment estimate and the second moment estimate of the gradients. To simplify the process of each coordinate updating of the CDbox-Adam algorithm, the CDbox-Adamax detection algorithm is also proposed. The CDbox-Adamax detection algorithm generalizes the 2-norm update rule of weights to the infinite norm. At the same time, an early stop criterion is proposed to efficiently avoid unnecessary iterations. Simulation results show that the early stop criterion reduces the number of iterations of the proposed detection algorithms. For a 12-mode MDM system impaired by MDL, the average number of iterations of the proposed detection algorithms is less than the CDbox detection algorithm. Thus, the proposed detection algorithms present lower computational complexity than the CDbox detection algorithm. Furthermore, compared with the conventional minimum mean square error (MMSE) detection algorithm, the proposed detection algorithms, CDbox-Adam and CDbox-Adamax, gain signal to noise ratio (SNR) improvement of 2.3 dB and 1.6 dB at BER = 10(-5) when MDL = 5 dB with QPSK and 16QAM, respectively. In the presence of MDL = 5 dB and 10 dB, when compared with the proposed detection algorithms with perfect CSI, the proposed detection algorithms with LS channel estimation requires 5.1 dB and 2.5 dB more of SNR to get
In order to accurately perform object detection by deep convolutional neural networks (DCNN) in videos, obtained from unmanned aerial vehicles (UAVs), many example images of objects containing annotations such as grou...
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ISBN:
(纸本)9798350343557
In order to accurately perform object detection by deep convolutional neural networks (DCNN) in videos, obtained from unmanned aerial vehicles (UAVs), many example images of objects containing annotations such as ground truth class information, bounding box, optical flow, occlusion and segmentation are required. Due to the difficulties faced during annotation of scenarios, and due to the inadequacy of the scenario diversity resulting from environmental conditions, a dataset containing above mentioned ground truths has not been found in the literature. In this study, synthetic aerial images with various annotation information were created in different scenarios while composing virtual worlds, and enhancing object detection algorithms is aimed. Enhancement of detection results of DCNN based object detection algorithms, trained with the support of synthetic aerial images, on real-world aerial images significantly, was observed during the experiments, conducted.
HiZ-GUNDAM is a future satellite mission designed for exploring the early universe using gamma-ray bursts (GRBs). The satellite is equipped with two main instruments: a wide field X-ray monitor (WFXM) and a near infra...
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ISBN:
(纸本)9781510675094;9781510675100
HiZ-GUNDAM is a future satellite mission designed for exploring the early universe using gamma-ray bursts (GRBs). The satellite is equipped with two main instruments: a wide field X-ray monitor (WFXM) and a near infrared telescope (NIRT). And its mission data processing unit (MPU) plays an important role in data processing. When a transient source occurs and the X-rays enter the WFXM, a cross-shaped image is produced on the focal plane image sensor. Once the WFXM's data are sent to the MPU, the direction of the source is determined from the center position. Furthermore, if there are no known stellar objects in this direction and if they are not hot pixels or other anomalies, the event is classified as a GRB candidate. To evaluate the software for this series of judgments, we investigated the angular resolution by this software algorithm utilizing the cross image obtained by the lobster eye optics (LEO).
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