Fast sparse fractal image compression.

As a structure-based image compression technology, fractal image compression (FIC) has been applied not only in image coding but also in many important image processing algorithms. However, two main bottlenecks restrained the develop and application of FIC for a long time. First, the encoding phase of FIC is time-consuming. Second, the quality of the reconstructed images for some images which have low structure-similarity is usually unacceptable. Based on the absolute value of Pearson's correlation coefficient (APCC), we had proposed an accelerating method to significantly speed up the encoding of FIC. In this paper, we make use of the sparse searching strategy to greatly improve the quality of the reconstructed images in FIC. We call it the sparse fractal image compression (SFIC). Furthermore, we combine both the APCC-based accelerating method and the sparse searching strategy to propose the fast sparse fractal image compression (FSFIC), which can effectively improve the two main bottlenecks of FIC. The experimental results show that the proposed algorithm greatly improves both the efficiency and effectiveness of FIC

Empirical Study on the Sustainable Development of Mountain Tourism in the Early Stage of High-Speed Railways—Taking the Southwest Mountainous Region of China as an Example

This study focuses on the early stage of high-speed railways (HSRs) and corrects problems in a timely manner and integrates the direction for tourism development. Its aim is to realize the sustainable development of mountain tourism in the southwest region of China. Based on the panel data from 2010 to 2019 of 39 cities in Guizhou, Guangxi, and Yunnan provinces, which are in the southwest mountainous region of China, and using data envelope analyses, the Malmquist productivity index, the Tobit model, and the intermediary effect, this study verifies the impact of core factors on the development efficiency of mountain tourism in the early stage of an HSR to find the problems existing in tourism development at present and in future stages. Results show the following: (1) In its early stage, an HSR is not yet the key factor to improve the efficiency of tourism development in the mountainous region. (2) The promotion effect of an HSR on the efficiency of tourism development is delayed. (3) In its early stage, an HSR breaks the balance of resource investment and wastes resources. (4) Taking HSRs is born out of the rigid demand of residents in the mountainous region rather than of their income levels. (5) Accessibility in mountain tourism plays a positive role between HSRs and the efficiency of tourism development

Empirical Study on the Sustainable Development of Mountain Tourism in the Early Stage of High-Speed Railways—Taking the Southwest Mountainous Region of China as an Example

This study focuses on the early stage of high-speed railways (HSRs) and corrects problems in a timely manner and integrates the direction for tourism development. Its aim is to realize the sustainable development of mountain tourism in the southwest region of China. Based on the panel data from 2010 to 2019 of 39 cities in Guizhou, Guangxi, and Yunnan provinces, which are in the southwest mountainous region of China, and using data envelope analyses, the Malmquist productivity index, the Tobit model, and the intermediary effect, this study verifies the impact of core factors on the development efficiency of mountain tourism in the early stage of an HSR to find the problems existing in tourism development at present and in future stages. Results show the following: (1) In its early stage, an HSR is not yet the key factor to improve the efficiency of tourism development in the mountainous region. (2) The promotion effect of an HSR on the efficiency of tourism development is delayed. (3) In its early stage, an HSR breaks the balance of resource investment and wastes resources. (4) Taking HSRs is born out of the rigid demand of residents in the mountainous region rather than of their income levels. (5) Accessibility in mountain tourism plays a positive role between HSRs and the efficiency of tourism development

Ionic-Liquid-Based CO2 Capture Systems: Structure, Interaction and Process

The inherent structure tunability, good affinity with CO2, and nonvolatility of ionic liquids (ILs) drive their exploration and exploitation in CO2 separation field, and has attracted remarkable interest from both industries and academia. The aim of this Review is to give a detailed overview on the recent advances on IL-based materials, including pure ILs, IL-based solvents, and IL-based membranes for CO2 capture and separation from the viewpoint of molecule to engineering. The effects of anions, cations and functional groups on CO2 solubility and selectivity of ILs, as well as the studies on degradability of ILs are reviewed, and the recent developments on functionalized ILs, IL-based solvents, and IL-based membranes are also discussed. CO2 separation mechanism with IL-based solvents and IL-based membranes are explained by combining molecular simulation and experimental characterization. Taking into consideration of the applications and industrialization, the recent achievements and developments on the transport properties of IL fluids and the process design of IL-based processes are highlighted. Finally, the future research challenges and perspectives of the commercialization of CO2 capture and separation with IL-based materials are posed.</p

Three examples to show the advantage of convergence of the proposed FSFIC scheme.

<p>The images in the first line are the reconstructed images in the quadtree FIC scheme, and the images in the second line are the reconstructed images in the proposed FSFIC scheme.</p

The relations of different values of the average pixel-based square error <i>e</i> with the reconstructed image quality, the compression ratio, and the encoding time for 512 × 512 images Lena, baboon, and pepper, respectively.

<p>The range size is 8 × 8, <i>k</i>₁ = 4, and <i>k</i>₂ is the number of all the domain blocks in the domain pool.</p

The relations of different values of <i>k</i>₂ with the reconstructed image quality, the compression ratio, and the encoding time for 512 × 512 images Lena, baboon, and pepper, respectively.

<p>The range size is 8 × 8, <i>k</i>₁ = 4, and the average pixel-based square error <i>e</i> = 25.</p

The generating process of the fast sparse fractal image compression (FSFIC) scheme.

<p>The generating process of the fast sparse fractal image compression (FSFIC) scheme.</p

PSNR/dB of the reconstructed images in BFIC scheme and BSFIC scheme.

<p>PSNR/dB of the reconstructed images in BFIC scheme and BSFIC scheme.</p

The optimum cases of the reconstructed image quality for different compression ratios with fixing <i>k</i>₂ as the number of all the domain blocks in the domain pool.

<p>The optimum cases of the reconstructed image quality for different compression ratios with fixing <i>k</i>₂ as the number of all the domain blocks in the domain pool.</p