With the widespread application of blockchain technology across various fields, the security of smart contracts has become increasingly important. In the field of anomaly detection, particularly in smart contract vulnerability detection, pre-trained models have demonstrated tremendous potential, improving the accuracy and efficiency of vulnerability detection. However, these models typically focus on a single modality, which limits their applicability. While integrating multiple models can mitigate this issue, effectively fusing features from different pretrained models remains a challenge that needs to be addressed.To tackle this problem, this paper proposes a feature fusion method for smart contract vulnerability detection based on pre-trained models (PFSCV). The method uses contrastive learning (CL) to capture fine-grained relational information between smart contracts, generating sample pairs based on the relationships between contracts to guide the fine-tuning of the pre-trained model CodeBERT, enabling it to learn contextual information from the source code. At the same time, the UnixCoder model is fine-tuned to extract data flow information from the contracts. Subsequently, we introduce an att-BiLSTM (Attention-based Bidirectional Long Short-Term Memory) model to fuse and integrate features extracted from different pre-trained models. Finally, extensive experiments on real-world smart contract datasets validate the effectiveness and reliability of the proposed method.
As an important part of blockchain technology, smart contracts have attracted strong interest from industry and academia. They provide the foundation for implementing various blockchain applications and play a key role in the blockchain ecosystem. However, the frequent occurrence of smart contract vulnerabilities has resulted in significant economic losses and serious damage to the blockchain-based credit system. Currently, the security and reliability of smart contracts have become an emerging research field. Recently, deep learning methods have achieved certain results in mitigating the vulnerability problem of smart contracts, with the BERT model being widely used due to its good performance. However, the existing BERT model solely relies on features extracted from the last layer, leading to incomplete classification features. To address this issue, we propose a multi-layer feature fusion model that can accurately identify smart contract vulnerabilities. Our fusion model integrates features from multiple layers of the BERT model and employs a series of fusion strategies to enhance the comprehensiveness and accuracy of the extracted features. We extensively tested and verified the effectiveness and performance advantages of our proposed multi-layer feature fusion model. Compared to traditional single-layer feature extraction methods, our model demonstrates higher accuracy and a lower false positive rate in identifying smart contract vulnerabilities.
As manufacturing, operations and maintenance become increasingly complex in the aviation sector, a digital transformation is underway toward Blockchain technology, an open source digital architecture for related data and their histories. From maintenance, repair and overhaul to protection against global positioning system spoofing, Blockchain technology is making a major impact in aviation industry. This paper analyzes possible implementation of Blockchain technology within the realm of Aviation Cybersecurity Framework.
Aiming at disaster relief emergency fund for tailings pond dam break and financing channels of compensation after disaster in China, with the goal of achieving passing and decentralization of tailings pond dam break risk and reducing the impact on social economic to the utmost, this thesis studied on catastrophe risk financing mode for tailings pond dam break. Through analysis, four main problems were obtained, including risks in relevant system of tailings pond dam break risk financing have not been effectively transferred, occupying production funds of enterprises, insufficient total amount of financing and narrow scope of compensation. Further integrating with foreign catastrophe risk financing experience and application cases of floods, earthquakes and others, catastrophe risk financing mode and operating mechanism suitable for China’s tailings pond dam break were put forward, catastrophe risk financing management mode dominated by government and assisted by commercial insurance company was formed, with the effectiveness and feasibility of such mode guaranteed through insurance technology, engineering risk prevention and increasing of coverage of insurance program.
In response to the mandates in the MINER Act of 2006, the National Institute for Occupational Safety and Health (NIOSH) conducted refuge alternatives research that included characterizing the utility, practicality and survivability of refuge chambers and outby safe havens. NIOSH also prepared and delivered a report to Congress in late December 2007 that summarized the findings of the research, included recommendations concerning the design and performance specifications for refuge alternatives, and focused on specific information that could inform the regulatory process on refuge alternatives. This paper highlights NIOSH’s research and recommendations concerning refuge alternatives, survivability evaluations of refuge chambers and presents a brief review of the current deployment of refuge chambers in underground coal mines in the U.S. The research has lead to the conclusion that refuge alternatives have the potential for saving the lives of mine workers if they are part of a comprehensive escape and rescue plan and if appropriate training is provided. Introduction The U.S. coal mining industry experienced an increase in fatalities during 2006 when 37 miners perished in the nation’s underground coal mines. Nineteen miners perished in three disasters: 12 miners perished in a methane explosion at the International Coal Group, Sago Mine, two more miners died in a fire at the Aracoma Coal Co., Alma No. 1 Mine, while another methane explosion resulted in the loss of five more miners at the Kentucky Darby, LLC, Darby No. 1 Mine. This reversed the downward trend of fatalities that had taken place during the previous 21 years (Fig. 1). The causes of all the underground coal mine fatalities in 2005, 2006 and 2007 are listed in Table 1. Table 1 illustrates that fewer fatalities occurred in 2005 and 2007 than 2006 with the goal of zero fatalities as desirable. The Mine Improvement and New Emergency Response Act of 2006 (MINER Act), PL 109-236, was passed in response to this increase in fatalities resulting from the three mine disasters that occurred in 2006 (United States, 2006). Section 13 of the Act – Research Concerning Refuge Alternatives, specifies NIOSH’s responsibilities with respect to refuge alternatives. Section 13, subsection (a) of the Act states that “The National Institute for Occupational Safety and Health (NIOSH) shall provide for the conduct of research, including field tests, concerning the utility, practicality, survivability and cost of various refuge alternatives in an underground coal mine environment, including commercially available portable refuge chambers.” Subsection (b)(1) then states that “Not later than 18 months after the date of enactment of this Act, the National Institute for Occupational Safety and Health shall prepare and submit to the Secretary of Labor, the Secretary of Health and Human Services, the Committee on Health, Education, Labor, and Pensions of the Senate, and the Committee on Education and the Workforce of the House of Representatives a report concerning the results of the research conducted under subsection (a), including any field tests.” This document summarizes NIOSH’s refuge alternatives research that was included in the report to the U.S. Congress. The concept of utilizing refuge chambers dates back as far as 1912 when the U.S. Bureau of Mines advocated the building of refuge chambers to fight mine fires (Rice, 1912) in the main sections of mines (Paul et al., 1923). In the late 1930s and early 1940s, some small refuge chambers had been established in some coal mines in the central states and these chambers saved lives (Harrington and Fene, 1941). In addition, the Harwick Coal and Coke Co. built a number of large refuge chambers in the Harwick Mine. These chambers were 23-m(75-ft-) long, 2.4m(8-ft-) high and 3.3-m(11-ft-) wide, cut out of the coal and connected to the surface by two boreholes to provide air, communications, food and water (Harrington and Fene, 1941). More recent research efforts were completed under contract for the U.S. Bureau of Mines starting around 1970 and extending into the mid-1980s. Five major contract efforts were completed between 1970 and 1983 that addressed mine rescue and survival, the design of explosion-proof bulkheads, post survival and rescue research needs, and guidelines for rescue chambers. As a result, one refuge chamber was constructed and is still located in NIOSH’s Bruceton Safety Research Coal Mine (Fig. 2). In general, these contract efforts did not point to any one specific component that would ensure survival during a mine disaster but stressed that survival is a collaboration of subsystems. The subsystems that make up the overall survival strategy include escape, rescue, communications, breathable air and barricading (refuge). NIOSH’s recent research on refuge alternatives was limited to underground coal mine applications. Historically, the use of refuge alternatives has been more prevalent in underground metal/nonmetal mines. The underlying differences between mining sectors are significant and practices in one sector cannot be generalized to the other. Even so, the findings from this research may be useful for metal/nonmetal application. The research efforts summarized in this document involved a number of activities. First, a literature search was performed to identify the findings from any past research on refuge alternatives and topics related to mine refuge and mine disasters, escape and mine rescue. Visits were made to mines, nationally and internationally, and meetings were held with mining experts from labor, industry and government in the U.S., Australia and South Africa to collect information on refuge alternatives, specific refuge regulations and to discuss contemporary issues associated with refuge alternatives. Several contract efforts were completed that examined existing U.S. and international practices, regulations and refuge products. However, these efforts revealed very little information related to coal mining refuge applications, while identifying several knowledge and technology gap areas. In response, a major research contract was awarded to address the gap areas, including guidance for locating and positioning refuge alternatives and establishing specifications for chambers and in-place shelters1. 1The gap areas were identified at the end of the international survey effort, which was performed during July through October 2006. The technical part of the contract to address these areas was completed at the end of October. The actual contract award, conducted in compliance with the Federal Acquisition Rules, was made in March 2007. Work on this contract will continue through 2009. The contractor was able to provide key inputs for the preparation of the report to Congress. Concurrently, NIOSH researchers examined nonminFIGURE 1 Underground coal mine fatalities 1987-2007 (Bauer Kohler, 2009.
The author argues that,in terms of policy,the establishment of China's public financial system laid the foundation for identifying and implementing the fiscal responsibility for compulsory education.Because compulsory education is a kind of pure public product,the government should completely bear the fiscal responsibility for it.We should integrate centralization with decentralization in labor-division among governments in different levels to realize a balanced development of compulsory education.The key for Beijing municipal government to implement the fiscal responsibility for compulsory education is to clarify the common responsibilities of city and local finance,and the municipal government should increase investment in compulsory education.