A quadratic-speed-dependent Voigt line shape (qSDV) with line mixing (qSDV+LM), together with spectroscopic line parameters from Devi et al. [1,2] for the 2v(3) band of CH4, was used to retrieve total columns of CH4 f...
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A quadratic-speed-dependent Voigt line shape (qSDV) with line mixing (qSDV+LM), together with spectroscopic line parameters from Devi et al. [1,2] for the 2v(3) band of CH4, was used to retrieve total columns of CH4 front atmospheric solar absorption spectra. The qSDV line shape (Tran et al., 2013) [3] with line mixing (Levy et al., 1992) [4] was implemented into the forward model of GFIT (the retrieval algorithm that is at the heart of the GGG software (Wunch et al., 2015) [5]) to calculate CH4 absorption coefficients. High-resolution laboratory spectra of CH4 were used to assess absorption coefficients calculated using a Voigt line shape and spectroscopic parameters from the atm line list (Toon, 2014) [6]. The same laboratory spectra were used to test absorption coefficients calculated using the qSDV+LM line shape with spectroscopic line parameters from Devi et al. [1,2] for the 2v(3) band of CH4 and a Voigt line shape for lines that don't belong to the 2v3 band. The spectral line list for lines that don't belong to the 2v(3) band is an amalgamation of multiple spectral line lists. We found that for the P, Q, and R branches of the 2v(3) band, the qSDV+LM simulated the laboratory spectra better than the Voigt line shape. The qSDV+LM was also used in the spectral fitting of high-resolution solar absorption spectra from four ground-based remote sensing sites and compared to spectra fitted with a Voigt line shape. The average root mean square (RMS) residual for 131,124 solar absorption spectra fitted with absorption coefficients calculated using the qSDV+LM for the 2v(3) band of CH4 and the new Spectral line list for lines for lines that don't belong to the 2v(3) band, was reduced in the P, Q and R branches by 5%, 13%, and 3%, respectively when compared with spectra fitted using a Voigt line shape and the atm line list. We found that the average total column of CH4 retrieved from these 131,124 spectra, With the qSDV+LM was 1.1 +/- 0.3% higher than the retrievals perfo
Previous work on autonomous formation flying guidance and control identified three key challenges to overcome in order to obtain a fully autonomous guidance and control loop: an accurate but simple model of relative m...
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Previous work on autonomous formation flying guidance and control identified three key challenges to overcome in order to obtain a fully autonomous guidance and control loop: an accurate but simple model of relative motion about elliptical and perturbed orbits, an efficient way of performing conflicting requirements trade-off with power-limited on-board computers, and finally an optimal or near-optimal control algorithm easy to implement on a flight computer. This paper first summarizes recent developments on each of these subject that help to overcome these challenges, developments which are then used as building blocks for an autonomous formation flying guidance and control system. This system autonomously performs trade-offs between conflicting requirements. i.e. minimization of fuel cost, formation accuracy and equal repartition of the fuel expenditure within the formation. Simulation results show that a complete guidance and control loop can be established using mainly analytical results and with very few numerical optimization which facilitates on-board implementation. (c) 2008 Elsevier Ltd. All rights reserved.
This research aims to propose a novel sub-optimal decentralised blanket coverage control algorithm, namely, 'one-Barrier-to-Blanket Coverage Algorithm' (BBCA) as well as a novel k-barrier coverage control algo...
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This research aims to propose a novel sub-optimal decentralised blanket coverage control algorithm, namely, 'one-Barrier-to-Blanket Coverage Algorithm' (BBCA) as well as a novel k-barrier coverage control algorithm, namely, 'one-to-k Barrier Coverage Algorithm' (1-kBCA) for self-deployed autonomous wireless sensor networks in the obstacle-free and convex deployment area. The motion coordination schemes developed in this research are based on the nearest neighbour techniques. Research indicates that simple motion coordination schemes have resulted in the powerful and intelligent control algorithms to achieve the desired coverage. Since the algorithms were developed based on simple local rules, they are indeed computationally efficient and ease the communication overheads. What is more, the superiorities of the proposed algorithms are nonetheless related to their uniformity, flexibility, simplicity, scalability as well as reliability. Instead of theoretical proofs as solid mathematical frameworks, computer simulations also have been presented to demonstrate the effectiveness of the proposed algorithms.
This paper considers some realization features of polynomial factoring algorithms for n-argument Boolean functions, as well as analyzes their computational complexity and necessary hardware resources.
This paper considers some realization features of polynomial factoring algorithms for n-argument Boolean functions, as well as analyzes their computational complexity and necessary hardware resources.
The problem of multifault rush repair in distribution networks (DNs) is a multiobjective dynamic combinatorial problem with topology constraints. The problem consists of archiving an optimal faults' allocation str...
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The problem of multifault rush repair in distribution networks (DNs) is a multiobjective dynamic combinatorial problem with topology constraints. The problem consists of archiving an optimal faults' allocation strategy to squads and an admissible multifault rush repairing strategy with coordinating switch operations. In this article, the utility theory is introduced to solve the first problem and a new discrete bacterial colony chemotaxis (DBCC) algorithm is proposed for the second problem to determine the optimal sequence for each squad to repair faults and the corresponding switch operations. The above solution is called the two-stage approach. Additionally, a double mathematical optimization model based on the fault level is proposed in the second stage to minimize the outage loss and total repairing time. The real-time adjustment multiagent system (RA-MAS) is proposed to provide facility to achieve online multifault rush repairing strategy in DNs when there are emergencies after natural disasters. The two-stage approach is illustrated with an example from a real urban distribution network and the simulation results show the effectiveness of the two-stage approach.
Many recent games and applications target the interactive exploration of realistic large scale worlds. These worlds consist mostly of static terrain models, as the simulation of animated fluids in these virtual worlds...
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Many recent games and applications target the interactive exploration of realistic large scale worlds. These worlds consist mostly of static terrain models, as the simulation of animated fluids in these virtual worlds is computationally expensive. Adding flowing fluids, such as rivers, to these virtual worlds would greatly enhance their realism, but causes specific issues: as the user is usually observing the world at close range, small scale details such as waves and ripples are important. However, the large scale of the world makes classical methods impractical for simulating these effects. In this paper, we present an algorithm for the interactive simulation of realistic flowing fluids in large virtual worlds. Our method relies on two key contributions: the local computation of the velocity field of a steady flow given boundary conditions, and the advection of small scale details on a fluid, following the velocity field, and uniformly sampled in screen space.
To solve the problem of low efficiency and poor effect of the current tone mapping methods for the high dynamic range images, the authors propose a hierarchical tone mapping algorithm based on colour appearance model....
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To solve the problem of low efficiency and poor effect of the current tone mapping methods for the high dynamic range images, the authors propose a hierarchical tone mapping algorithm based on colour appearance model. The discrete Gaussian kernel is used to speed up the bilateral filter. The operation of tone compression in RGB colour space is adopted to correct the colour casts. The extreme values of the pixels are also adjusted in the detail layer. Moreover, after the tone mapping, the colour saturation is enhanced in the image regions of rich details and sharp edges. Experimental results show that the proposed algorithm with less computational cost reduces the halo effect significantly, and achieves the natural colour and the rich details. It outperforms the state-of-the-art methods in terms of visual quality and objective indicators.
The performance of Massive MIMO is severely limited by channel estimation error, which is caused by pilot contamination and channel aging. In this paper, we propose an estimation algorithm based on the weighted total ...
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The performance of Massive MIMO is severely limited by channel estimation error, which is caused by pilot contamination and channel aging. In this paper, we propose an estimation algorithm based on the weighted total least-squares method with errors-invariables (EIV) model to alleviate the influence of pilot contamination and channel aging. Then, a channel rectification method has been investigated to diminish the inaccuracy of channel estimation. Comparing with the traditional methods, it not only helps to make the signal estimation more accurate, but also provides opportunities to correct the channel model with estimation error and update the aged channel statement information. Simulations are provided to verify the efficacy of this method.
Image-based rendering (IBR) involves constructing an image from a new viewpoint, using several input images from different viewpoints. A rendering framework must be flexible enough to handle this kind of data. It must...
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Image-based rendering (IBR) involves constructing an image from a new viewpoint, using several input images from different viewpoints. A rendering framework must be flexible enough to handle this kind of data. It must also be able to handle data extracted from several input images using far less accurate techniques--for example, stereo matching, which introduces a high level of uncertainty. The authors' attempt to define this uncertainty and use it in their rendering framework. When synthesizing new images from real input images, IBR techniques often neglect to take advantage of all the knowledge gathered from computer vision techniques during depth recovery. The authors' image-rendering approach involves three steps: depth extraction, uncertainty estimation, and rendering. Uncertainty is a vague term, which can refer to various aspects of the input images. For example, it can relate to the intrinsic or extrinsic camera parameters. Their technique of rendering depth with uncertainty using ellipsoidal Gaussian kernels is straightforward. They represent each depth uncertainty as an ellipsoid. INSET: Perspective Projection Approximation..
Multi-agent systems (MAS) are ubiquitous in the real world, typical examples include sensor networks, group robots, and birds flock. Consensus is one of the most typical dynamical behaviors of MAS which implies the st...
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Multi-agent systems (MAS) are ubiquitous in the real world, typical examples include sensor networks, group robots, and birds flock. Consensus is one of the most typical dynamical behaviors of MAS which implies the states of a group reach some identical value or trajectory asymptotically. It has been widely demonstrated that discrete-time MAS can realize consensus when there does not exist information delay from any node to itself, however, the phenomenon of self delay is possible to occur in cases like sensor aging, actuator delay, or computation incapacity. To characterize such a behavior, this paper introduces an MAS model with dynamically changing topologies by considering both self and transmission delays. Moreover, a simple consensus criterion for such a model is proposed. To prove the correctness of such a criterion, we propose a novel method which is based on the intrinsic relationship between joint and sequential connectivity, it should be noted that such a method does not rely on the widely used Wolfowitz's theorem for convergence of infinite products of stochastic matrices. (C) 2016 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.
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