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With the development of blockchain technology, due to the different system architecture and application scenarios of blockchain platforms, it is difficult to realize the interconnection and intercommunication of data and assets on different blockchains, which affects the promotion and application of blockchain. The cross-chain tech-nology of blockchain is an important technical solution to realize the interconnection of blockchain and improve the interoperability and extensibility of blockchain. The blockchain cross-chain protocol is the specific design specifi-cations to realize the cross-chain interoperability between different blockchains through cross-chain technology, so it is of great significance to the realization of blockchain interoperability and the construction of blockchain cross-chain application. This paper systematically arranges and analyzes the latest researches on the integration and implemen-tation of blockchain cross-chain protocols, and places them in four hierarchies: Firstly, the current research status of blockchain cross-chain interoperability is explained from three aspects, Internet of blockchains, cross-chain techno-logy and blockchain interoperability. Secondly, the cross-chain protocols are divided into cross-chain communi-cation agreements, cross-chain asset transaction agreements and cross-chain smart contract call agreements, and the latest research is analyzed. Thirdly, the key design principles of cross-chain protocols are summarized, and the solutions for the problems of security, privacy and scalability of cross-chain protocol are provided. Finally, com-bined with the actual needs of blockchain cross-chain applications, the future research direction of blockchain cross-chain protocol is given.

Blockchain provides a new technology for building transmission and trust mechanism of social ralue. The rapid development of blockchain has promoted the deep integration of smart contract with artificial Intelligence, big data and internet of things, so its security has attracted attention. In recent years, researches on security of blockchain and smart contract have made great progress. Thus, based on smart contract on the blockchain, the related works on security of operating mechanism, on-chain smart contract security and off-chain security were classified, analyzed, compared, summarized and discussed. The hot issues of smart contract security in the future were forecasted.

In order to improve kinematic single epoch positioning accuracy and realize real-time processing, the article presents a precise kinematic single epoch positioning algorithm using moving window wavelet denoising. Firstly, we obtain the observation residuals by using the conventional single epoch method and improve end effect by data extending a part of the current epoch. Secondly, we denoise the current epoch observation residuals using a window wavelet, and achieve an adaptive selection of the wavelet decomposition level for denoising through cross-validation. Finally, we achieve final positioning accuracy using the clean observations, after denosing. Comparing the proposed method with conventional single epoch positioning, experimental results show that positioning accuracy has been improved greatly for different motions. The results were consistent with those from wavelet post processing. [ABSTRACT FROM AUTHOR]

Objective: To compare the difference in the clinical efficacy on infantile food accumulation treated with centripetal tuina therapy at spleen meridian site of different location., Methods: Sixty cases of infantile food accumulation were randomized into a palmar thumb surface group and a radial margin group, 30 cases in each one. In the palmar thumb surface group, the spleen meridian was stimulated with the pushing technique centripetally on the palmar side of the thumb. In the radial margin group, the spleen meridian was stimulated with the pushing, technique centripetally along the radial margin of the thumb. The traditional tuina techniques, such as tuisanguan, yun neibagua were combined in the two groups. The treatment was given once a day, 6 times a week, 12 treatments as one session. After the 1 session of treatment, the main symptom scores before and after treatment were compared in the patients of the two groups, the improvements in the accompanied symptoms were observed, such as appetite, defecation and tongue coating; and the efficacy was evaluated in the two groups., Results: The total effective rates were 93.3% (28/30) and 90.0% (27/30) in the palmar thumb surface group and the radial margin group respectively and the difference was not significant statistically in comparison of the two groups (P > 0.05). After treatment, the main symptom score was improved significantly in the two groups, indicating the significant difference as compared with that before treatment (both P < 0.05). The improvement in foul breathing in the palmar thumb surface group was better than that in the radial margin group (P < 0.05)., Conclusion: Between the two kinds of pushing techniques at spleen meridian site, pushing on the palmar surface of the thumb and pushing along the radial margin, there is no difference in the total efficacy on infantile food accumulation. Regarding the improvement in foul breathing, the effect in the palmar thumb surface group is better than that in the radial margin group.

Objective: To determine the predicative significance of HRV and HRT to premature beat on patients with coal-worker's pneumoconiosis., Methods: 100 coal-worker's pneumoconiosis patients with premature beat (including 44 cases of occasional ventricular premature contraction and 56 cases of frequent ventricular premature contraction) were chosen as CWP group, and 50 healthy coal workers were chosen as control group. 24 h DCG was used to monitor and analyze the change of premature beat and to calculate HRV. Index: SDNN, SDANN, HFLF, HRT: TO, TS, compare HRV of CWP group and control group and the changes of HRT of both occasional and frequent ventricular premature contraction., Results: The incidence of CWP at night (66.1%, 37 cases) is higher than that during daytime (33.9%, 19 cases), and the difference is statistically significant with P < 0.05. HRV (SDNN SDANN HF HL) indexes of CWP group are lower than control group, and the difference is statistically significant with P < 0.05. HRV indexes of control group at night are higher than that during daytime, and the difference is statistically significant with P < 0.05. Comparison of CWP group HRV indexes between day and night is statistically insignificant with P > 0.05. Compared with control group, TO of CWP group is higher while TS is lower, and the difference is statistically significant with P < 0.05. Compared with occasional ventricular premature contraction patients in CWP group, TO of frequent ventricular premature contraction patients is higher while TS is lower, and the difference is statistically significant with P < 0.05., Conclusion: Frequent ventricular premature contraction group in CWP group suffer from severe impaired autonomic nervous function injury, and abnormal HRV and HRT can be prognostic indicator of frequent ventricular premature contraction among coal-worker's pneumoconiosis patients.

Objective: Risk assessment and risk control for occupational exposure to chemical toxicants were performed on an isophorone nitrile device with an annual production of 5,000 tons, based on improved Singaporean semi-quantitative risk assessment method, with consideration of actual situation in China and in the present project., Methods: With the use of engineering analysis and identification of occupational hazards in the improved Singaporean semi-quantitative risk assessment method, hazard rating (HR) and risk assessment were performed on chemical toxicants from an isophorone nitrile device with an annual production of 5,000 tons., Results: The chemical toxicants in the isophorone nitrile device were mainly isophorone, hydrocyanic acid, methanol, phosphoric acid, sodium hydroxide, and sodium cyanide; the HR values were mild hazard (2), extreme hazard (5), mild hazard (2), mild hazard (2), moderate hazard (3), and extreme hazard (5), respectively, and the corresponding exposure rating (ER) values were 2.09, 2.72, 2.76, 1.68, 2.0, and 1.59, respectively. The risk of chemical toxicants in this project was assessed according to the formula Risk = [HR×ER](1/2). Hydrocyanic acid was determined as high risk, sodium hydroxide and sodium cyanide as medium risk, and isophorone, methanol, and phosphoric acid as low risk. Priority in handling of risks was determined by risk rating. The table of risk control measure was established for pre-assessment of occupational hazards., Conclusion: With risk assessment in this study, we concluded that the isophorone nitrile device with 5,000 ton annual production was a high-occupational hazard device. This device is a project of extreme occupational hazard. The improved Singaporean semi-quantitative risk assessment method is a scientific and applicable method, and is especially suitable for pre-evaluation of on-site project with no analogy.