To improve spectral X-ray CT reconstructed image quality, the energy-weighted reconstructed image xbins^W and the separable paraboloidal surrogates（SPS） algorithm are proposed for the prior image constrained compres...
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To improve spectral X-ray CT reconstructed image quality, the energy-weighted reconstructed image xbins^W and the separable paraboloidal surrogates（SPS） algorithm are proposed for the prior image constrained compressed sensing（PICCS）-based spectral X-ray CT image reconstruction. The PICCS-based image reconstruction takes advantage of the compressed sensing theory, a prior image and an optimization algorithm to improve the image quality of CT *** evaluate the performance of the proposed method, three optimization algorithms and three prior images are employed and compared in terms of reconstruction accuracy and noise characteristics of the reconstructed images in each energy *** experimental simulation results show that the image xbins^W is the best as the prior image in general with respect to the three optimization algorithms; and the SPS algorithm offers the best performance for the simulated phantom with respect to the three prior images. Compared with filtered back-projection（FBP）, the PICCS via the SPS algorithm and xbins^W as the prior image can offer the noise reduction in the reconstructed images up to 80. 46%, 82. 51%, 88. 08% in each energy bin,respectively. M eanwhile, the root-mean-squared error in each energy bin is decreased by 15. 02%, 18. 15%, 34. 11% and the correlation coefficient is increased by 9. 98%, 11. 38%,15. 94%, respectively.
NBTI-induced PMOS transistor aging has become an important influence factor of the circuit reliability in the current technological dimension. In this paper, Multi-Vth technique based on potential critical paths for N...
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NBTI-induced PMOS transistor aging has become an important influence factor of the circuit reliability in the current technological dimension. In this paper, Multi-Vth technique based on potential critical paths for NBTI effect and leakage tradeoff is proposed. The potential critical paths can be found at the preset timing margin and the critical gates in the potential critical paths can be replaced with the low threshold voltage type through the optimization algorithm mentioned in our paper. The experimental results on ISCAS85 benchmark circuits at 45nm node show that the after-aging delay improvement rate is up to 12.95%, which is obviously better than the current multi-threshold voltage scheme. Simultaneously, the leakage power overhead is less. Our method is more effective for the larger circuit in the anti-aging aspect.
Quantum-behaved particle swarm optimization (QPSO), a global optimization method, is a combination of particle swarm optimization (PSO) and quantum mechanics. It has a great performance in the aspects of search abilit...
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Quantum-behaved particle swarm optimization (QPSO), a global optimization method, is a combination of particle swarm optimization (PSO) and quantum mechanics. It has a great performance in the aspects of search ability, convergence speed, solution accuracy and solving robustness. However, the traditional QPSO still cannot guarantee the finding of global optimum with probability 1 when the number of iterations is limited. A novel way of computing the local attractor for QPSO is proposed to improve QPSO's performance in global searching, and this novel QPSO is denoted as EQPSO during which we can guarantee the particles are diversiform at the early stage of iterations, and have a good performance in local searching ability at the later stage of iteration. We also discuss this way of computing the local attractor in mathematics. The results of test functions are compared between EQPSO and other optimization techniques (including six different PSO and seven different optimization algorithms), and the results found by the EQPSO are better than other considered methods.
The high efficiency video coding（HEVC） standard was developed by JCT-VC in 2010 and was officially released in 2013. Compared to the previous video coding standard of H.264/AVC, HEVC can save about 50% bit-rate for ...
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The high efficiency video coding（HEVC） standard was developed by JCT-VC in 2010 and was officially released in 2013. Compared to the previous video coding standard of H.264/AVC, HEVC can save about 50% bit-rate for equal perceptual video quality, but the computational complexity significantly increases. Therefore current research is focusing on decreasing the computational complexity and improving the coding timeliness of the HEVC video coding algorithm.
In this paper, a coherent perfect absorption (CPA)-type AND gate based on plasmonic nano particle is proposed. It consists of two plasmonic nano rod arrays on top of two serial arms with quartz substrate. The operatio...
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In this paper, a coherent perfect absorption (CPA)-type AND gate based on plasmonic nano particle is proposed. It consists of two plasmonic nano rod arrays on top of two serial arms with quartz substrate. The operation principle is based on the absorbable formation of a conductive path in the dielectric layer of a plasmonic nano-particles waveguide. Since the CPA efficiency depends strongly on the number of plasmonic nano-rod and the nano rod location, an efficient binary optimization method based the Particle Swarm optimization (PSO) algorithm is used to design an optimized array of the plasmonic nano-rod in order to achieve the maximum absorption coefficient in the 'off state and the minimum absorption coefficient in the 'on' state. In Binary PSO (BPSO), a group of birds consists a matrix with binary entries, control the presence ('1') or the absence ('0') of nano rod in the array.
Basing on the introduction of Multidisciplinary Design optimization (MDO), Multidisciplinary Design optimization method based on iSIGHT is given, which includes one general process model and one optimization algorithm...
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ISBN:
(纸本)9783037851913
Basing on the introduction of Multidisciplinary Design optimization (MDO), Multidisciplinary Design optimization method based on iSIGHT is given, which includes one general process model and one optimization algorithm. optimization of one bearing is selected as one example. According to its application, it approves that MDO methods can solve practical engineering problems more effectively because of comprehensive consideration of the internal problems in all disciplines.
In this paper, a coherent perfect absorption-type NOR gate based on plasmonic nano particles is proposed. It consists of two plasmonic nanorod arrays on top of two serial arms with quartz substrate. The operation prin...
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In this paper, a coherent perfect absorption-type NOR gate based on plasmonic nano particles is proposed. It consists of two plasmonic nanorod arrays on top of two serial arms with quartz substrate. The operation principle is based on the absorbable formation of a conductive path in the dielectric layer of a plasmonic nanoparticle waveguide. Because the coherent perfect absorption efficiency depends strongly on the number of plasmonic nanorods and the locations of nanorods, an efficient binary optimization method based the Particle Swarm optimization algorithm is used to design an optimized array of the plasmonic nanorods in order to achieve the maximum absorption coefficient in the off' state and the minimum absorption coefficient in the on' state. In Binary Particle Swarm optimization, a group of birds consists a matrix with binary entries, control the presence (1') or the absence (0') of nanorods in the array. Copyright (c) 2016 John Wiley & Sons, Ltd.
With increasing importance being attached to big data mining, analysis, and forecasting in the field of wind energy, how to select an optimization model to improve the forecasting accuracy of the wind speed time serie...
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With increasing importance being attached to big data mining, analysis, and forecasting in the field of wind energy, how to select an optimization model to improve the forecasting accuracy of the wind speed time series is not only an extremely challenging problem, but also a problem of concern for economic forecasting. The artificial intelligence model is widely used in forecasting and data processing, but the individual back-propagation artificial neural network cannot always satisfy the time series forecasting needs. Thus, a hybrid forecasting approach has been proposed in this study, which consists of data preprocessing, parameter optimization and a neural network for advancing the accuracy of short-term wind speed forecasting. According to the case study, in which the data are collected from Peng Lai, a city located in China, the simulation results indicate that the hybrid forecasting method yields better predictions compared to the individual BP, which indicates that the hybrid method exhibits stronger forecasting ability.
The pump structure greatly influences the characteristics of a diode side-pumped laser. To achieve high absorption efficiency and a homogeneous pump-beam distribution simultaneously, a systemic algorithm has been esta...
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ISBN:
(纸本)9780819483737
The pump structure greatly influences the characteristics of a diode side-pumped laser. To achieve high absorption efficiency and a homogeneous pump-beam distribution simultaneously, a systemic algorithm has been established to optimize the pump structure, where multiple reflections occur on the internal wall of the reflector inside the pump chamber. A novel design of an efficient, highly reliable, and good beam quality diode side-pumped solid-state laser is presented. Effort has been done to obtain a highly uniform pumping intensity in the active area, which simultaneously reduces the effects of thermal gradient. In this design a novel lens duct configuration is used. By this way a uniform power distribution and a maximum absorption of pump power is resulted. Numerical analysis also indicates the superiority of the design to other methods such as direct and diffusive pumping techniques.
Cloud computing provides a framework for supporting end users easily attaching powerful services and applications through Internet. To give secure and reliable services in cloud computing environment is an important i...
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Cloud computing provides a framework for supporting end users easily attaching powerful services and applications through Internet. To give secure and reliable services in cloud computing environment is an important issue. Providing security requires more than user authentication with passwords or digital certificates and confidentiality in data transmission, because it is vulnerable and prone to network intrusions that affect confidentiality, availability and integrity of Cloud resources and offered services. To detect DoS attack and other network level malicious activities in Cloud, use of only traditional firewall is not an efficient solution. In this paper, we propose a cooperative and hybrid network intrusion detection system (CH-NIDS) to detect network attacks in the Cloud environment by monitoring network traffic, while maintaining performance and service quality. In our NIDS framework, we use Snort as a signature based detection to detect known attacks, while for detecting network anomaly, we use Back-Propagation Neural network (BPN). By applying snort prior to the BPN classifier, BPN has to detect only unknown attacks. So, detection time is reduced. To solve the problem of slow convergence of BPN and being easy to fall into local optimum, we propose to optimize the parameters of it by using an optimization algorithm in order to ensure high detection rate, high accuracy, low false positives and low false negatives with affordable computational cost. In addition, in this framework, the IDSs operate in cooperative way to oppose the DoS and DDoS attacks by sharing alerts stored in central log. In this way, unknown attacks that were detected by any IDS can easily be detected by others IDSs. This also helps to reduce computational cost for detecting intrusions at others IDS, and improve detection rate in overall the Cloud environment.
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