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A digital watermark technique based on the wavelet transform is presented in the paper. To ensure the security of the watermark image, the watermark image is scrambled before embedding. According to the characteristics of the multiresolution decomposition of the wavelet transform, the watermark values in different directions and subbands are added by various intensities to the corresponding directions...
We proposed a method to estimate the laser phase noise using the phase noise to intensity noise conversion based on the direct detection (DD) technique. It is shown by simulation that the estimated results approach when the laser line-width is no larger than 1MHz. Besides, compared with coherent detection -based phase noise estimation, the DD technique provides cost-efficient solutions.
A Wiener deconvolution approach is proposed to monitor optical power of O-OFDM superchannel network. The impacts of TOF's bandwidth and scanning steps on power estimation performance have been studied. Simulation results show that the proposed approach can accurately monitor the power of various transmission systems via low cost TOF with optimized parameters.
Many link prediction methods via local or global information have been proposed, which are important measures to infer relationship between members in an incomplete network. Given an incomplete network, the common methods we adopted are some similarity-based measures, which still have defects and imperfect parts. In order to enhance the prediction result, we propose a method based on the degree of...
Ultra-fine optical spectrum microscope is demonstrated based on optical channel estimation using coherent optical OFDM signals and optical spectrum fusion technique. The frequency resolution and measurement range of this technique are 10.7-MHz and 250-GHz respectively.
In mobile network, the network topological structure is dynamic, which leads to the resource searching become very difficult. This paper analyzes the key problems of resources search in mobile network, and introduces agent to determine the network topology, meanwhile, using improved ant colony optimization to find resource. It is effective for the mobile network resource searching.
For the past few years, the Location-Based Service (LBS) is becoming more and more important for people's life. On the one hand, it is easy to told people that where is they are anytime, On the other hand, the privacy of location issues attract more and more attention. This paper analyzes the key problems of location privacy protection, and gives a survey of existing work including the model of privacy...
Country risk is a quite important factor for international investment. Many institutions and researchers try to assess country risk by using numerous indicators and various evaluation models. This paper investigates the dynamic behavior of country risk in order to offer more detailed information of country risk to investors. First, country beta is taken as the proxy of country risk. Second, dynamic...
This paper develops a methodology to aggregate the market, credit and operational risk and derive the economic capital. While the data is obtained by mapping the profit & loss items of income statement into risk types, the dependence structure between the risks is modeled through the combination of mutual information and copulas, which enables to capture both linear and non-linear dependence...
We demonstrate a novel method based on DD-OFDM to measure the property of passive optical components. In experiment, we realize the transfer function measurement of the delay interferometer (DI) with 3.9-MHz resolution and an ultra-fast measurement speed.
A microwave photonic single bandpass filter is proposed and successfully demonstrated. The principle is based on the Hi-Bi FBG-FP cavity transmission to break the amplitude balance of PM sidebands and achieve effective PM-AM conversion.
A widely tunable microwave photonic single bandpass filter is proposed and successfully demonstrated. The principle is based on the concept of using Brillouin selective sideband amplification to achieve effective PM-AM conversion.
The signal reconstruction problems of Compressed Sensing is equal to a nonsmooth optimization problem. Since the original signal is sparse, a new l1 -Minimization reconstruction algorithm is proposed based on modified trust region method of nonsmooth optimization. The algorithm can also reconstruct signal in super-linear convergence rate. Simulation results show that the algorithm is robust in reconstructing...
Bit-interleaved coded modulation with iterative decoding (BICM-ID) can achieve better performance than BICM in both AWGN and Rayleigh fading channels because of the feedback algorithm. However, some existing decoding schemes in BICM-ID cannot perform well in both computational complexity and decoding performance. The Max-Log-MAP algorithm has lower computational complexity with worse decoding performance...
Using selective subcarrier-filling and pre-emphasis techniques, we experimentally demonstrated 24-Gbps optical DD-OFDM signal transmitted over 40-km SSMF without using dispersion compensation and optical amplifiers based on a 1310nm EML. BER is lower than 2e-3.
The objective of this study is to assess the correlation between the prefrontal cerebral oxygenation oscillations measured by near-infrared spectroscopy (NIRS) and cerebral artery hemodynamic parameters as measured by transcranial Doppler (TCD). The cerebral oxygenation signal was monitored for 10 minutes from the left prefrontal lobe using NIRS. TCD monitoring was performed to measure the hemodynamic...
The severity loss distribution is the main topic in operational risk estimation. In this paper, we propose a novel model for quantifying operational risk in the framework of the loss distribution approach (LDA) as suggested by the Basel II. We use Cornish¡VFisher Expansion, which is non-parameter method, to fit operational risk loss severity, and then we use simulation technique to measure the operational...
In this paper according to the radiation environment of Beijing Electron Positron Collider (BEPC) synchrotron radiation hall, the neutron detector design is finished by using MCNP cord. Then the calibration and physics test of detectors are finished. Using the detector the measurements of radiation level in BEPC synchrotron radiation hall were carried out. The measurement of high energy dose rate...
This paper describes in detail the equipment, the process, the configuration of the computer control system, the control strategy and the algorithm of gauge control system in experimental mill for hot flat rolling. Two-stage computer control system is used. They are respectively basic automation system and process control system. The process parameters, such as gap and plate thickness, can be accurately...
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