Xinjiang University of Finance and Economics

Xia T., Ji Q., Zhang D., Han J.

Promoting the development of renewable energy has become the key factor to solve the problems of energy and climate change issues. However, its development is largely constrained by the prices of traditional fossil energy. This paper explores the influence of various fossil energy price changes on renewable energy stock returns using a network approach. Specifically, a positive and negative returns network and value-at-risk (VaR) network are constructed separately for identifying the asymmetric and extreme information spillover. Our findings show the fossil energy–renewable energy network system has a relatively high level of interdependence. The electricity market behaves as the major contributor to the changes of renewable energy returns in the returns connectedness network, while oil and coal contribute most to the changes of renewable energy returns in the VaR connectedness network. The dynamic results show that the contributions of fossil energy price changes to renewable energy returns have strong time-varying pattern with high volatility over time. The total connectedness in the positive returns network is slightly stronger than that in the negative returns network for most of the time during our sample period.

Liu H., Kadir A., Xu C.

Based on the classic quadratic map (CQM) with abundant bifurcations and periodic windows, a new 3D improved coupling quadratic map (3D-ICQM) is constructed, and its phase diagram, Lyapunov exponent (LE) and randomness testing by TestU01 demonstrated that it has better ergodicity, more complex nonlinear behavior, larger chaotic range and better randomness. To investigate its application in cryptography, a 3D-ICQM based color image encryption algorithm with round key expansion is designed. To further enhance the randomness of key stream, the hash value of intermediate cipher of the previous round is converted into new initial values and fed back into 3D-ICQM, to generate the key stream for the current round. The security and statistical analyses demonstrated that the encryption scheme has better security performance than several existing algorithms.

Zhu B., Zhou X., Liu X., Wang H., He K., Wang P.

In this study, value at risk and conditional value at risk are used to measure the risks of pilot carbon markets of Beijing, Shanghai, Guangdong, Tianjin, Hubei, Shenzhen and Chongqing in China. Regular vine copula-CoES is used to measure the risk spillover effects among carbon markets of Guangdong, Hubei and Shenzhen with high transactions. The empirical results show that compared with the traditional value at risk, conditional value at risk can better measure the risks of carbon markets. Carbon markets of Chongqing, Tianjin and Shenzhen have higher risks than those of Hubei and Guangdong. Risk spillover effects are found between carbon markets of Guangdong and Shenzhen, rather than between those of Hubei and Guangdong.

Dong G., Wang F., Shekhtman L.M., Danziger M.M., Fan J., Du R., Liu J., Tian L., Stanley H.E., Havlin S.

Significance In real-world scenarios, many subnetworks interact with other subnetworks to form a modular interacting network system. In previous models, it was assumed that all subnetworks may be linked pairwise; however, in real systems, only some pairs of subnetworks are connected. Understanding how to develop theoretical frameworks and study system resilience of general coupling patterns of the subnetworks is of significant importance for designing and optimizing economic, social, and infrastructure networks. Here we present two frameworks for such systems having specific coupling patterns to investigate their resilience. Specifically, we find an optimal level of interaction between subnetworks, which maximizes the system’s resilience to failures. Our findings highlight the need to consider real-world coupling patterns and possible optimizations for designing resilient systems.

Liu H., Kadir A., Xu C.

In recent years, a large number of S-Box design schemes have been proposed. However, after detection we found that most of them contain fixed point or reverse fixed point, which may be an exploitable weakness in cryptography. In order to design a strong S-Box construction algorithm, and eliminate fixed point and reverse fixed point intelligently, we first designed an improved coupling quadratic map (ICQM), which is surjective and has good ergodicity and randomness, verified by bifurcation diagram, Lyapunov exponent and strict randomness testing tool of TestU01. Then we reconstructed a keyed strong S-Box scheme without weakness based on ICQM and backtracking. Experiments results indicated the effectiveness of the proposed S-Box construction scheme.

Shen B., Yang X., Xu Y., Ge W., Liu G., Su X., Zhao S., Dagestani A.A., Ran Q.

Industrial structure low-carbon restructuring is an essential channel to accelerate China’s economic growth and fulfilling carbon emission reduction goals. Whether carbon emission trading pilot policy, as an influential carbon reduction instrument, fosters industrial structure low-carbon restructuring is of major significance to green economic development. This paper empirically investigates the shock of the carbon emission trading pilot policy on industrial structure low-carbon restructuring using the differences-in-differences (DID) and synthetic control method (SCM). Statistics reveal that sectors with low carbon productivity, such as electricity, steam, and hot water production and supply, ferrous metal smelting and pressing, etc., and sectors with high carbon productivity, such as electrical equipment and machinery, electronics and telecommunication equipment, etc. The industrial structure did not develop a stable trend of change before the 12th Five-Year Plan, but a stable trend of low-carbon restructuring emerged after such a period. Carbon emission trading pilot policy significantly facilitates industrial structural low-carbon restructuring. Carbon emission trading pilot policy inhibits energy-intensive industries in the industrial sector significantly, which promotes industrial structure low-carbon restructuring. Therefore, policymakers need to develop a nationwide carbon emission trading market that includes more industries to guide production factors to industrial sectors with high carbon productivity for industrial restructuring and dual carbon goals.

Ge T., Qiu W., Li J., Hao X.

This study uses panel data from 281 cities in China during the period 2004-2016 and the two-regime spatial Durbin model to investigate the strategic interactions of environmental regulation efficiency loss between cities. It adopts the spatial lag of X model and the mediating effect model to analyze the effect and mechanisms of environmental regulation efficiency loss on inclusive growth. The results show that there are asymmetric strategic interactions in the form of imitative competition and upward competition between geographically neighboring cities, which exacerbates the environmental regulation efficiency loss. The environmental regulation efficiency loss of local and neighboring cities inhibits inclusive growth at both the national and regional levels. At the regional level, the local and neighbor effects are the strongest in the central and western regions. The results also show that the inhibition of the neighbor effect is more obvious within 500 km and is relatively stable after 2007. Revenue decentralization, fiscal autonomy, and promotion pressure have a partial mediating effect, which may be important channels for the environmental regulation efficiency loss to restrain inclusive growth. However, expenditure decentralization plays a masking effect, which mitigates the inhibition of the environmental regulation efficiency loss on inclusive growth. In addition, the robustness test of the informal environmental regulation efficiency loss supports the conclusions of the formal environmental regulation efficiency loss. Moreover, the inhibitions of the two are similar at the national level but are different at the regional level. This study therefore suggests that policymakers should adopt a series of measures to improve environmental regulation efficiency, in addition to increasing environmental regulation intensity.

Guan J., Yao J., Li M., Li D., Zheng J.

Extreme climate events can cause large risks to ecosystems and human society in a short period. Investigating the changing trends of such events is essential for regional climate risk management. However, there is limited information on the regional assessment of the history and future trends of extreme climate events in Xinjiang, China. This study investigated the historical changes and projected trends of extreme climate events in Xinjiang based on observational data and Coupled Model Intercomparison Project phase 6 (CMIP6) model simulations. The results showed that the bias correction effectively reduced the bias of the CMIP6 model to the extreme climate indices simulation. During the period 1961–2014, the extreme indices representing warmth showed robust growth, while the extreme indices representing cold showed a robust decline. The intensity and frequency indices of extreme precipitation continued to increase, while consecutive dry days (CDDs) shortened and consecutive wet days (CWDs) lengthened. The changing trend of the extreme temperature indices had strong spatial consistency, while the changing trend of the extreme precipitation indices had obvious spatial heterogeneity. Based on the CMIP6 model simulations, the extreme climate indices in the twenty-first century were projected to continue the changing trend of the historical period (1961–2014). Compared with north Xinjiang (NXJ) and south Xinjiang (SXJ), the cold spell duration index (CSDI), cold nights (TN10p), cold days (TX10p), and extreme precipitation events in the Tianshan Mountains (TSM) were projected to experience stronger changes in the twenty-first century. The response of extreme temperature and extreme precipitation indices to global warming was approximately linear. Compared with SSP585, most extreme climate indices under the SSP245 scenario changed slightly in response to global warming. The superposition of the increase (decrease) in extreme warm (cold) events and the increase in extreme precipitation events will exacerbate the threat of extreme climate events to the agricultural and ecological security of the Xinjiang oasis, especially in the TSM. Given the limited water vapor sources and precipitation and the high rate of evapotranspiration, it is projected that the current situation of water shortages in Xinjiang will not be fundamentally changed.

Qiu W., Zhang J., Wu H., Irfan M., Ahmad M.

Based on the panel data of 46 countries in “Belt and Road” (B&R) from 2004 to 2016, this paper studies the impact of innovation investment and institutional quality on green total factor productivity (GTFP). Firstly, the ICRG database, World Bank WDI database, Traditional Foundation database, and Wind database are matched to obtain the balanced panel data of 46 countries along the B&R from 2004 to 2016. Secondly, the Malmquist-Luenberger index, which can be included in the unexpected output, is used to calculate the GTFP of countries along B&R. Thirdly, the evaluation system of national institutional quality of B&R is constructed from three dimensions (political institutional quality, economic institutional quality, and legal institutional quality), and the overall system quality of different countries is measured by entropy method. Finally, an empirical study is made on the relationship among innovation investment, institutional quality, and green total factor productivity. The results show that innovation investment has significantly promoted the GTFP of the B&R countries. It is worth noting that there is a non-linear relationship between innovation investment and GTFP in the B&R countries. With the improvement of overall system quality, political system quality, economic system quality, and legal system quality, the promotion effect of innovation investment on GTFP is further enhanced. In addition, the heterogeneity regression results show that the impact of innovation investment on GTFP is significantly heterogeneous in different regions of the B&R countries. Specifically, innovation investment has the greatest impact on GTFP in South Asia, followed by East Asia and Pacific, Europe and Central Asia, Middle East, and North Africa.

Dai W., Xu X., Song X., Li G.

The data space for audio signals is large, the correlation is strong, and the traditional encryption algorithm cannot meet the needs of efficiency and safety. To solve this problem, an audio encryption algorithm based on Chen memristor chaotic system is proposed. The core idea of the algorithm is to encrypt the audio signal into the color image information. Most of the traditional audio encryption algorithms are transmitted in the form of noise, which makes it easy to attract the attention of attackers. In this paper, a special encryption method is used to obtain higher security. Firstly, the Fast Walsh–Hadamar Transform (FWHT) is used to compress and denoise the signal. Different from the Fast Fourier Transform (FFT) and the Discrete Cosine Transform (DCT), FWHT has good energy compression characteristics. In addition, compared with that of the triangular basis function of the Fast Fourier Transform, the rectangular basis function of the FWHT can be more effectively implemented in the digital circuit to transform the reconstructed dual-channel audio signal into the R and B layers of the digital image matrix, respectively. Furthermore, a new Chen memristor chaotic system solves the periodic window problems, such as the limited chaos range and nonuniform distribution. It can generate a mask block with high complexity and fill it into the G layer of the color image matrix to obtain a color audio image. In the next place, combining plaintext information with color audio images, interactive channel shuffling can not only weaken the correlation between adjacent samples, but also effectively resist selective plaintext attacks. Finally, the cryptographic block is used for overlapping diffusion encryption to fill the silence period of the speech signal, so as to obtain the ciphertext audio. Experimental results and comparative analysis show that the algorithm is suitable for different types of audio signals, and can resist many common cryptographic analysis attacks. Compared with that of similar audio encryption algorithms, the security index of the algorithm is better, and the efficiency of the algorithm is greatly improved.