A Survey of DeFi Security: Challenges and Opportunities

DeFi, or Decentralized Finance, is based on a distributed ledger called blockchain technology. Using blockchain, DeFi may customize the execution of predetermined operations between parties. The DeFi system use blockchain technology to execute user transactions, such as lending and exchanging. The total value locked in DeFi decreased from \$200 billion in April 2022 to \$80 billion in July 2022, indicating that security in this area remained problematic. In this paper, we address the deficiency in DeFi security studies. To our best knowledge, our paper is the first to make a systematic analysis of DeFi security. First, we summarize the DeFi-related vulnerabilities in each blockchain layer. Additionally, application-level vulnerabilities are also analyzed. Then we classify and analyze real-world DeFi attacks based on the principles that correlate to the vulnerabilities. In addition, we collect optimization strategies from the data, network, consensus, smart contract, and application layers. And then, we describe the weaknesses and technical approaches they address. On the basis of this comprehensive analysis, we summarize several challenges and possible future directions in DeFi to offer ideas for further research

wash trading in NFT market

As emerging digital assets, NFTs are susceptible to anomalous trading behaviors due to the lack of stringent regulatory mechanisms, potentially causing economic losses. In this study, we conduct the first systematic analysis of four non-fungible token (NFT) markets, each operating under different rules.</p

wash trade in the market

As emerging digital assets, NFTs are susceptible to anomalous trading behaviors due to the lack of stringent regulatory mechanisms, potentially causing economic losses. In this study, we conduct the first systematic analysis of four non-fungible token (NFT) markets, each operating under different rules.</p

Unveiling Wash Trading in Popular NFT Markets

As emerging digital assets, NFTs are susceptible to anomalous trading behaviors due to the lack of stringent regulatory mechanisms, potentially causing economic losses. In this paper, we conduct the first systematic analysis of four non-fungible tokens (NFT) markets. Specifically, we analyze more than 25 million transactions within these markets, to explore the evolution of wash trade activities. Furthermore, we propose a heuristic algorithm that integrates the network characteristics of transactions with behavioral analysis, to detect wash trading activities in NFT markets. Our findings indicate that NFT markets with incentivized structures exhibit higher proportions of wash trading volume compared to those without incentives. Notably, the LooksRare and X2Y2 markets are detected with wash trading volume proportions as high as 94.5% and 84.2%, respectively.Comment: This paper has been accepted by WWW 202

Willingness of returning migrant workers to purchase houses: A case study of 45 villages in Henan Province, China

The willingness of returning migrant workers to purchase houses has an important impact on local urbanization. At present, there are few researches on the willingness of returning migrant workers to purchase houses. The existing researches mostly focus on the perspective of sociology and economics, and few studies are conducted from the perspective of geography. Based on the survey data of 45 villages in Henan Province of China in 2019, this study used binary logistic method to study the influencing factors of the willingness of returning migrant workers to purchase houses. The willingness of returning migrant workers to purchase houses is affected by many factors, such as personal, family, village, and returning factors. Among them, age and returning period are negatively correlated with the willingness of returning migrant workers to purchase houses. Factors such as years of education, years of working, and per capita income of village are positively correlated with the willingness of returning migrant workers to purchase houses. Returning migrant workers in plains and hilly areas are more willing to purchase houses than those in mountainous areas. The formation of the willingness to purchase houses is mainly related to economic foundation, age, marital status, and other factors. Returning migrant workers are becoming more willing to purchase houses, and the expected locations are mainly concentrated in the county seats. In the context of China's high density of rural population and rapid urbanization, more returning migrant workers are expected to purchase houses in cities and towns for the sake of employment, marriage, children's education, and access to public services. As a result, there is an extensive market of potential purchasers, which affects the development of the local urban real estate industry and is of great significance for returning migrant workers to truly integrate into the cities. However, some returning migrant workers still choose to purchase houses in villages, mainly affected by traditional concepts, living habits, and the better development of villages. Therefore, it is of great practical significance to explore the willingness of returning migrant workers to purchase houses, so as to master the flow laws and future behavior of returning migrant workers to purchase houses

Additional file 3: of BRD7 expression and c-Myc activation forms a double-negative feedback loop that controls the cell proliferation and tumor growth of nasopharyngeal carcinoma by targeting oncogenic miR-141

Table S2. Ten putative c-Myc-binding sites were predicted in the miR-141 promoter region from the JASPAR Database. (DOC 40 kb

Additional file 2: of BRD7 expression and c-Myc activation forms a double-negative feedback loop that controls the cell proliferation and tumor growth of nasopharyngeal carcinoma by targeting oncogenic miR-141

Figure S1. c-Myc did not influence the processing of pri-miR-141 and pre-miR-141 in miR-141 biosynthesis. Figure S2. BRD7 was inactivated by c-Myc and did not affect the stability of c-Myc protein. Figure S3. The levels of miR-141 restoration in c-Myc knockdown NPC cells. (DOC 2382 kb

Additional file 1: of BRD7 expression and c-Myc activation forms a double-negative feedback loop that controls the cell proliferation and tumor growth of nasopharyngeal carcinoma by targeting oncogenic miR-141

Table S1. The primers for confirmation of the c-Myc-binding sites in the miR-141 and BRD7 promoter. (DOC 34 kb