Proxy Re-encryption based Fair Trade Protocol for Digital Goods Transactions via Smart Contracts

With the massive amount of digital data generated everyday, transactions of digital goods become a trend. One of the essential requirements for such transactions is fairness, which is defined as that both of the seller and the buyer get what they want, or neither. Current fair trade protocols generally involve a trusted third-party (TTP), which achieves fairness by heavily relying on the TTP's behaviors and the two parties' trust in the TTP. With the emergence of Blockchain, its decentralization and transparency make it a very good candidate to replace the TTP. In this work, we attempt to design a secure and fair protocol for digital goods transactions through smart contracts on Blockchain. To ensure security of the digital goods, we propose an advanced passive proxy re-encryption (PRE) scheme, which enables smart contracts to transfer the decryption right to a buyer after receiving his/her payment. Furthermore, based on smart contracts and the proposed passive PRE scheme, a fair trade protocol for digital goods transactions is proposed, whose fairness is guaranteed by the arbitration protocol. The proposed protocol supports Ciphertext publicity and repeatable sale, while involving less number of interactions. Comprehensive experiment results validate the feasibility and effectiveness of the proposed protocol

Stakeholder Orientation and Corporate Payout Policy: Insights from State Legal Shocks

We employ a difference-in-differences estimation approach to examine the impact of stakeholder orientation on corporate payout policy. The empirical test exploits the enactment of US state-level constituency statutes, which allow directors to consider stakeholders and long-term interests in corporate decision making. We find that firms incorporated in states that have adopted constituency statutes significantly reduce share repurchases, whereas the effects of statute enactment on total payout and dividend payments are marginal and insignificant, respectively. We further show that the negative statute effect on share repurchases is more pronounced for firms that are in financial distress or are close to default, and firms in consumer-focused and high-polluting industries. Overall, our findings indicate that promoting stakeholder orientation can have a significant impact on corporate payout decisions

Spatio-temporal variations and influencing factors of polycyclic aromatic hydrocarbons in atmospheric bulk deposition along a plain-mountain transect in western China

Ten atmospheric bulk deposition (the sum of wet and dry deposition) samplers for polycyclic aromatic hydrocarbons (PAHs) were deployed at a plain-mountain transect (namely PMT transect, from Daying to Qingping) in Chengdu Plain, West China from June 2007 to June 2008 in four consecutive seasons (about every three months). The bulk deposition fluxes of ∑15-PAHs ranged from 169.19 μg m−2 yr−1 to 978.58 μg m−2 yr−1 with geometric mean of 354.22 μg m−2 yr−1. The most prevalent PAHs were 4-ring (39.65%) and 3-ring (35.56%) PAHs. The flux values were comparable to those in rural areas. Higher fluxes of total PAHs were observed in the middle of PMT transect (SL, YX and JY, which were more urbanized than other sites). The seasonal deposition fluxes in the sampling profile indicated seasonality of the contaminant source was an important factor in controlling deposition fluxes. PAHs bulk deposition was negatively correlated with meteorological parameters (temperature, wind speed, humidity, and precipitation). No significant correlations between soil concentrations and atmospheric deposition were found along this transect. PAHs in soil samples had combined sources of coal, wood and petroleum combustion, while a simple source of coal, wood and grass combustion for bulk deposition. There were significant positive correlation relationship (p < 0.05) between annual atmospheric bulk deposition and local PAHs emission, with biomass burning as the major contribution to the total emission of PAHs. This transect acts as an important PAHs source rather than being a sink according to the ratio of deposition/emission. Mountain cold trap effect existed in this transect where the altitude was higher than 1000 m. Long-range transport had an impact on the bulk deposition in summer. And this transect was a source to Tibetan only in summer. The forward trajectory analysis showed most air masses did not undergo long-range transport due to the blocking effect of surrounding mountains. Only a few air masses (<10%) arrived at the eastern and northern region of China or farther regions via long-range transport

Stakeholder orientation and corporate payout policy: Insights from state legal shocks

We employ a difference-in-differences estimation approach to examine the impact of stakeholder orientation on corporate payout policy. The empirical test exploits the enactment of US state-level constituency statutes, which allow directors to consider stakeholders and long-term interests in corporate decision making. We find that firms incorporated in states that have adopted constituency statutes significantly reduce share repurchases, whereas the effects of statute enactment on total payout and dividend payments are marginal and insignificant, respectively. We further show that the negative statute effect on share repurchases is more pronounced for firms that are in financial distress or are close to default, and firms in consumer-focused and high-polluting industries. Overall, our findings indicate that promoting stakeholder orientation can have a significant impact on corporate payout decisions

Numerical Simulation of Coupled Fractional Differential-Integral Equations Utilizing the Second Kind Chebyshev Wavelets

In order to solve coupled fractional differential-integral equations more effectively and to deal with the problem that the huge algebraic equations lead to considerable computational complexity and large data storage requirements in the calculation process, this paper approximates the function of the unknown solution based on the Chebyshev wavelet of the second kind and then combines the collocation method to solve the numerical solution of nonlinear fractional Fredholm integral-differential equations. By using the proposed method, the original problem can be reduced to a system of linear algebraic equations, which can be easily solved by some mathematical techniques. In addition, the convergence analysis of the system based on the second kind of Chebyshev wavelet is studied. Several numerical test problems are presented, and the absolute error values under different fractional orders are given, which proves the superiority and effectiveness of the proposed method. It provides support for improving the precision and reliability of the system