From the perspective of civil subject theory,law of value,comparative law and history of laws,the thesis expounds that the contract on the transfer of the contractual right of rural lands is in nature a civil contract...From the perspective of civil subject theory,law of value,comparative law and history of laws,the thesis expounds that the contract on the transfer of the contractual right of rural lands is in nature a civil contract instead of an administrative one.Then it explores the defects in the contract from the viewpoint of legal value goal,contract law and legal sociology,that is,the relevant provisions in Rural Land Contract Law and Explanations of Supreme People's Court about the Issues concerning the Laws Applicable to the Trial of Cases of Disputes over Rural Land Contracting go against the principle of free contracting and run counter to the legal value goal of justice,so they do not achieve good implementing effect.Finally,the thesis demonstrates and makes some practical legislative proposals to perfect the contract system for circulation of the right to operate constructed rural lands,aiming at improving the circulation rate through perfecting the contract of the right to rural land contractual management,solving the disputes in rural lands circulation and safeguarding the legitimate rights of the farmers.展开更多
EDITOR＇S NOTE： The Draft Labor Contract Law of the People＇s Republic of China has been completed and was published for soliciting comments on March 20. In a short period of one month, 191,849 pieces of comments and...EDITOR＇S NOTE： The Draft Labor Contract Law of the People＇s Republic of China has been completed and was published for soliciting comments on March 20. In a short period of one month, 191,849 pieces of comments and opinions were received. Prior to the promulgation of the law, this reporter interviewed Mr. Guan Huai, a noted Chinese expert in labor law, professor of the Law School of the Renmin University of China and law advisor to the All-China Federation of Trade Unions.展开更多
As blockchain technology rapidly evolves,smart contracts have seen widespread adoption in financial transactions and beyond.However,the growing prevalence of malicious Ponzi scheme contracts presents serious security ...As blockchain technology rapidly evolves,smart contracts have seen widespread adoption in financial transactions and beyond.However,the growing prevalence of malicious Ponzi scheme contracts presents serious security threats to blockchain ecosystems.Although numerous detection techniques have been proposed,existing methods suffer from significant limitations,such as class imbalance and insufficient modeling of transaction-related semantic features.To address these challenges,this paper proposes an oversampling-based detection framework for Ponzi smart contracts.We enhance the Adaptive Synthetic Sampling(ADASYN)algorithm by incorporating sample proximity to decision boundaries and ensuring realistic sample distributions.This enhancement facilitates the generation of high-quality minority class samples and effectively mitigates class imbalance.In addition,we design a Contract Transaction Graph(CTG)construction algorithm to preserve key transactional semantics through feature extraction from contract code.A graph neural network(GNN)is then applied for classification.This study employs a publicly available dataset from the XBlock platform,consisting of 318 verified Ponzi contracts and 6498 benign contracts.Sourced from real Ethereum deployments,the dataset reflects diverse application scenarios and captures the varied characteristics of Ponzi schemes.Experimental results demonstrate that our approach achieves an accuracy of 96%,a recall of 92%,and an F1-score of 94%in detecting Ponzi contracts,outperforming state-of-the-art methods.展开更多
Due to mobile Internet technology's rapid popularization,the Industrial Internet of Things(IIoT)can be seen everywhere in our daily lives.While IIoT brings us much convenience,a series of security and scalability ...Due to mobile Internet technology's rapid popularization,the Industrial Internet of Things(IIoT)can be seen everywhere in our daily lives.While IIoT brings us much convenience,a series of security and scalability issues related to permission operations rise to the surface during device communications.Hence,at present,a reliable and dynamic access control management system for IIoT is in urgent need.Up till now,numerous access control architectures have been proposed for IIoT.However,owing to centralized models and heterogeneous devices,security and scalability requirements still cannot be met.In this paper,we offer a smart contract token-based solution for decentralized access control in IIoT systems.Specifically,there are three smart contracts in our system,including the Token Issue Contract(TIC),User Register Contract(URC),and Manage Contract(MC).These three contracts collaboratively supervise and manage various events in IIoT environments.We also utilize the lightweight and post-quantum encryption algorithm-Nth-degree Truncated Polynomial Ring Units(NTRU)to preserve user privacy during the registration process.Subsequently,to evaluate our proposed architecture's performance,we build a prototype platform that connects to the local blockchain.Finally,experiment results show that our scheme has achieved secure and dynamic access control for the IIoT system compared with related research.展开更多
This paper investigates a sliding-mode model predictive control （MPC） algorithm with auxiliary contractive sliding vector constraint for constrained nonlinear discrete-time systems. By adding contractive constraint ...This paper investigates a sliding-mode model predictive control （MPC） algorithm with auxiliary contractive sliding vector constraint for constrained nonlinear discrete-time systems. By adding contractive constraint into the optimization problem in regular sliding-mode MPC algorithm, the value of the sliding vector is decreased to zero asymptotically, which means that the system state is driven into a vicinity of sliding surface with a certain width. Then, the system state moves along the sliding surface to the equilibrium point within the vicinity. By applying the proposed algorithm, the stability of the closed-loop system is guaranteed. A numerical example of a continuous stirred tank reactor （CSTR） system is given to verify the feasibility and effectiveness of the proposed method.展开更多
We examine the economics of royalties in bioprospecting contracts between a pharmaceutical and genetic resource supplier （local）, with an eve to understanding the relative advantages of indexing royalty, payments to...We examine the economics of royalties in bioprospecting contracts between a pharmaceutical and genetic resource supplier （local）, with an eve to understanding the relative advantages of indexing royalty, payments to gross revenue or net revenue. We show a risk-averse firm facing only production or only cost risks will index royalties to net revenue. When facing both types of risk the choice of royalty type depends on the relative magnitudes of the production and cost risk. In each case, the risk-averse firm chooses the royalty-type that shifts as much risk as possible to the local. Wheat the local is risk neutral the pharmaceutical＇s and local＇s preferences are compatible.If the local is risk averse and there is only one type of risk, it will prefer a gross revenue royalty, and shift as much risk as possible to the firm： here the local and firm preferences are compatible only ifthe firm is risk-neutral. Lastly we show if the firm sets the terms of the contract and both agents are risk averse, the.firm will not likely volunteer to implement the socially optimal royalty arrangement as it prefers to shift as much risk to the loeal, who now also prefers a more certain return, This last outcome is at the heart of the benefit sharing discussionand suggests if risk sharing and equity are a concern in benefit sharing, then the choice of rcyalty type can be an important part of negotiations between pharmaceuticals and locals for the phytochemical from nature for new drug discovery.展开更多
surveys the evolution of the contract system of 'responsibility linked to production' in the cooperative economy of China’s socialist agricultural sector and makes a critical analysis of the old model in whic...surveys the evolution of the contract system of 'responsibility linked to production' in the cooperative economy of China’s socialist agricultural sector and makes a critical analysis of the old model in which labor was deployed in a concentrated way and remuneration paid according to workpoints. He thereby brings to light two specific characteristics of China’s agriculture—the scattered and independent nature of the labor and the unified control and coordination over the process of production by the combination of households—and the two requirements resulting from these. The author holds that the key to the economic nature of the 'contract system of responsibility linked to production' lies in two unique, often puzzling, economic phenomena in the cooperative economy under the system of collective ownership: 1. labor is carried out independently and in a decentralized manner; and 2. remuneration is not based on workpoints but is directly obtained by individuals according to the product. In the process of analyzing these two phenomena, the author differentiates the modes of labor and the relations of production, and clarifies the process of production of the rural contract system’s combination of centralization and decentralization, and the essence of the two-tiered policy. He also formulates the category of 'standard output' to describe a characteristic of the mode of distribution in the rural contract system, that is, the calculation of remuneration according to a standard output. The paper also discusses the rural economy and its development after the institution of the contract system of 'responsibility linked to production' but due to limited space this will be published in a later article.展开更多
With the development of intelligent bionic robots and the improvement of military application,a single robot cannot meet the requirements of the tasks of the current era.The more complex tasks require not only that th...With the development of intelligent bionic robots and the improvement of military application,a single robot cannot meet the requirements of the tasks of the current era.The more complex tasks require not only that the robot be able to pass through the field barriers and the amphibious environment,but also that the robot be able to collaborate in a multi-robot system.Consequently,research on the multi-robot control system of spherical amphibious robots is very important.Presently,the main research on amphibious robots is to improve the functions of a single robot,in the absence of the study of the multi-robot control system.Existing systems primarily use a centralized control methodology.Although the transfer of central node can be achieved,there is still a problem of Byzantine fault tolerance in military applications,that is,when the amphibious multi-robot system is invaded by the enemy.The central node may not only fail to accomplish the task,but also lose control of other robots,with severe consequences.To solve the above problems,this paper proposed a decentralized method of spherical amphibious multi-robot control system based on blockchain technology.First,the point-to-point information network based on long range radio technology of low power wide area network was set up,we designed the blockchain system for embedded application environment and the decentralized hardware and software architecture of multi-robot control system.On this basis,the consensus plugin,smart contract and decentralized multi-robot control algorithm were designed to achieve decentralization.The experimental results of consensus of spherical amphibious multi-robot showed the effectiveness of the decentralization.展开更多
With the further development of service-oriented,performance-based contracting(PBC)has been widely adopted in industry and manufacturing.However,maintenance optimization problems under PBC have not received enough att...With the further development of service-oriented,performance-based contracting(PBC)has been widely adopted in industry and manufacturing.However,maintenance optimization problems under PBC have not received enough attention.To further extend the scope of PBC’s application in the field of maintenance optimization,we investigate the condition-based maintenance(CBM)optimization for gamma deteriorating systems under PBC.Considering the repairable single-component system subject to the gamma degradation process,this paper proposes a CBM optimization model to maximize the profit and improve system performance at a relatively low cost under PBC.In the proposed CBM model,the first inspection interval has been considered in order to reduce the inspection frequency and the cost rate.Then,a particle swarm algorithm(PSO)and related solution procedure are presented to solve the multiple decision variables in our proposed model.In the end,a numerical example is provided so as to demonstrate the superiority of the presented model.By comparing the proposed policy with the conventional ones,the superiority of our proposed policy is proved,which can bring more profits to providers and improve performance.Sensitivity analysis is conducted in order to research the effect of corrective maintenance cost and time required for corrective maintenance on optimization policy.A comparative study is given to illustrate the necessity of distinguishing the first inspection interval or not.展开更多
Iterated function systems （IFS） were introduced by Hutchinson in 1981 as a natural generalization of the well-known Banach contraction principle. In 2010, D. R. Sahu and A. Chakraborty introduced K-Iterated Function...Iterated function systems （IFS） were introduced by Hutchinson in 1981 as a natural generalization of the well-known Banach contraction principle. In 2010, D. R. Sahu and A. Chakraborty introduced K-Iterated Function System using Kannan mapping which would cover a larger range of mappings. In this paper, following Hutchinson, D. R. Sahu and A. Chakraborty, we present some new iterated function systems by using the so-called generalized contractive mappings, which will also cover a large range of mappings. Our purpose is to prove the existence and uniqueness of attractors for such class of iterated function systems by virtue of a Banach-like fixed point theorem concerning generalized contractive mappings.展开更多
This paper examines the bipartite consensus problems for the nonlinear multi-agent systems in Lurie dynamics form with cooperative and competitive communication between different agents. Based on the contraction theor...This paper examines the bipartite consensus problems for the nonlinear multi-agent systems in Lurie dynamics form with cooperative and competitive communication between different agents. Based on the contraction theory, some new conditions for the nonlinear Lurie multi-agent systems reaching bipartite leaderless consensus and bipartite tracking consensus are presented. Compared with the traditional methods, this approach degrades the dimensions of the conditions, eliminates some restrictions of the system matrix, and extends the range of the nonlinear function. Finally, two numerical examples are provided to illustrate the efficiency of our results.展开更多
With the rise of blockchain technology,the security issues of smart contracts have become increasingly critical.Despite the availability of numerous smart contract vulnerability detection tools,many face challenges su...With the rise of blockchain technology,the security issues of smart contracts have become increasingly critical.Despite the availability of numerous smart contract vulnerability detection tools,many face challenges such as slow updates,usability issues,and limited installation methods.These challenges hinder the adoption and practicality of these tools.This paper examines smart contract vulnerability detection tools from 2016 to 2023,sourced from the Web of Science(WOS)and Google Scholar.By systematically collecting,screening,and synthesizing relevant research,38 open-source tools that provide installation methods were selected for further investigation.From a developer’s perspective,this paper offers a comprehensive survey of these 38 open-source tools,discussing their operating principles,installation methods,environmental dependencies,update frequencies,and installation challenges.Based on this,we propose an Ethereum smart contract vulnerability detection framework.This framework enables developers to easily utilize various detection tools and accurately analyze contract security issues.To validate the framework’s stability,over 1700 h of testing were conducted.Additionally,a comprehensive performance test was performed on the mainstream detection tools integrated within the framework,assessing their hardware requirements and vulnerability detection coverage.Experimental results indicate that the Slither tool demonstrates satisfactory performance in terms of system resource consumption and vulnerability detection coverage.This study represents the first performance evaluation of testing tools in this domain,providing significant reference value.展开更多
Background:This study aimed to review treatments and evaluate the aesthetic outcomes,complications,and reoperation rates regarding surgical correction for a postoperative contracted nose.Methods:PubMed,MEDLINE,and Emb...Background:This study aimed to review treatments and evaluate the aesthetic outcomes,complications,and reoperation rates regarding surgical correction for a postoperative contracted nose.Methods:PubMed,MEDLINE,and Embase databases were searched for studies detailing aesthetic outcomes and complications of surgical correction of a contracted nose.Surgical procedures,adjuvant treatment,outcomes,and complications were synthesized and analyzed.Results:Nine articles encompassing 376 patients were included in the systematic review,and six articles(198 participants)were included in the meta-analysis.The most frequently used graft material was the autologous rib cartilage(61.1%).Surgical procedures were heterogeneous in these studies.The nasolabial angle reduced by 9.52°(95%confidence interval(CI):(-11.95,-7.09),P<0.0001),and the nasal length increased significantly(standardized mean difference(SMD)=2.25,95%CI:(1.26,2.23),P<0.00001).However,the evidence was insufficient to determine a significant change in the columellar-labial angle(SMD=-0.95,95%CI:(-2.19,0.29),P=0.13)and columellar-lobular angle(SMD=2.39,95%CI:(-1.20,5.97),P=0.19).Aesthetic dissatisfaction(12.5%)and infection(4.5%)were the most commonly reported complications.Reoperation was performed in 5.3%of patients.Conclusion:Surgical correction can increase the nasal length,reduce the nasolabial angle,and have a low reoperation rate.No significant improvement in the columellar-labial or columellar-lobular angle was observed.展开更多
We developed an eccentric contraction induced electrical stimulation (ES) training system. The purpose of this study was to investigate whether the eccentric contraction induced ES enhance the knee extension torque co...We developed an eccentric contraction induced electrical stimulation (ES) training system. The purpose of this study was to investigate whether the eccentric contraction induced ES enhance the knee extension torque compared with typical ES. Twenty-two young untrained men (age: 23 ± 3 years) in the acute response trial (single training) and seven untrained men in the long period training trial (for 6 weeks) were studied. We measured muscle thickness and knee extension torque evoked by ES with eccentric contraction training system (ES + ECC) or ES alone for the quadriceps muscle of men. The levels of pain and discomfort were evaluated using numeric rating scale (NRS) and heart rate variability. The knee extension torque of ES + ECC was higher than that of ES alone in the acute response trial. There were no significant differences in the levels of pain and discomfort between ES and ES + ECC. Additionally, ES + ECC training for 6 weeks was effective on the quadriceps muscle thickness and knee extension torque. In contrast, the ES alone training failed to increase muscle thickness and knee extension torque. These results suggest that eccentric contraction induced ES would have the potential to become an effective intervention to promote muscle strengthening.展开更多
The study was conducted with the aim of exploring the barriers to the adoption of BOT contract systems for infrastructural development of technical universities in Ghana. In an empirical questionnaire survey with prof...The study was conducted with the aim of exploring the barriers to the adoption of BOT contract systems for infrastructural development of technical universities in Ghana. In an empirical questionnaire survey with professionals and experts in the construction and education sector, the respondents were invited to rate their perception on the barriers to the adoption of the BOT contracts systems. An interview session to satisfy ways of adopting the BOT contracts for infrastructural development in technical universities was conducted with selected professionals. The study revealed that the major barriers to the adoption of the BOT contract system are: delays in approval, corruption, reliability and credit worthiness of entities and expropriation. The study suggested that detailed policy or framework for implementing BOT contracts;proper planning by technical universities;and adequate protection for lenders is required for successful BOT implementation. Therefore there is a need to explore this concept, using adequate policy initiatives, proper measures and support from government to improve on the proper implementation of the BOT contracts in Technical Universities in Ghana.展开更多
Based on the applicable principle of liquidated damages in ＂contract law＂, based on the improvement of the system, the article first analyzes the status quo of the development of the default system and secondly puts...Based on the applicable principle of liquidated damages in ＂contract law＂, based on the improvement of the system, the article first analyzes the status quo of the development of the default system and secondly puts forward some suggestions for improvement. The final purpose is to perfect the liquidated damages system with the Contract Law, in a bid to enhance the fairness of liquidated damages.展开更多
The realty(real estate)management of ownership of buildings includes the owner(homeowner)entrust-management and the owner self-management,the former through the way of realty service contracts,the latter through the r...The realty(real estate)management of ownership of buildings includes the owner(homeowner)entrust-management and the owner self-management,the former through the way of realty service contracts,the latter through the resolution of the owners’assembly and the owners’committee.The legal disputes of realty service contracts involve balancing interests among the realty service enterprise,individual owner,and all the owners.We should use dynamic balancing of the interests of the three parties to implement the interests of the win-win cooperation rather than the interests of the trade-off of“all or nothing.”The realty service contract is similar to the entrustment contract,both of which are based on the owners’entrustment.The duty to provide realty service is not simply equivalent to fiduciary duty.The realty service contract has the essence of both behavior debt and result debt.For the former,the general provisions of the entrustment contract can be referred to,and for the latter,the general provisions of the contract for work can be referred to.In view of the group characteristics of the realty service contract,owners have no right to terminate the realty service contract at any time but should obey the principle of due process and take the majority mechanism to make a dismissal resolution resolution.The resolutions and management stipulations worked out by the owners’assembly in a majority mechanism,both of which belong to resolution behavior and are legal tools of the owners’autonomy,shall be binding on all the owners.The relationship between the owner,the owner’s assembly,and the owner’s committee is similar to the fiduciary relationship.If the decision made by the owners’assembly or the owners’committee and the management stipulation infringes upon the legal rights and interests of the owners,the injured owner has the right to revocation litigation.At present,residential commodity owners have a relatively low degree of autonomy in China,and legal disputes over realty services are frequent.In the future,we need to perfect the legal incentive and constraint measures,and stimulate the vitality of owner autonomy to promote better implementation of the owner self-management and owner entrust-management.展开更多
The current Internet web trust system is based on the traditional PKI system, to achieve the purpose of secure communication through the trusted third party. However, with the increase of network nodes, various proble...The current Internet web trust system is based on the traditional PKI system, to achieve the purpose of secure communication through the trusted third party. However, with the increase of network nodes, various problems appear in the centralization system of public key infrastructure (PKI). In recent years, in addition to cryptographic problems, attacks against PKI have focused on the single point of failure of certificate authority (CA). Although there are many reasons for a single point of failure, the purpose of the attack is to invalidate the CA. Thus a distributed authentication system is explored to provide a feasible solution to develop distributed PKI with the rise of the blockchain. Due to the automation and economic penalties of smart contracts, a PKI system is proposed based on smart contracts. The certificate chain was constructed in the blockchain, and a mechanism was adopted for auditing access to CA nodes in the blockchain. Experimental results show that security requirements of CA are met in this system.展开更多
Smart contracts are widely used on the blockchain to implement complex transactions,such as decentralized applications on Ethereum.Effective vulnerability detection of large-scale smart contracts is critical,as attack...Smart contracts are widely used on the blockchain to implement complex transactions,such as decentralized applications on Ethereum.Effective vulnerability detection of large-scale smart contracts is critical,as attacks on smart contracts often cause huge economic losses.Since it is difficult to repair and update smart contracts,it is necessary to find the vulnerabilities before they are deployed.However,code analysis,which requires traversal paths,and learning methods,which require many features to be trained,are too time-consuming to detect large-scale on-chain contracts.Learning-based methods will obtain detection models from a feature space compared to code analysis methods such as symbol execution.But the existing features lack the interpretability of the detection results and training model,even worse,the large-scale feature space also affects the efficiency of detection.This paper focuses on improving the detection efficiency by reducing the dimension of the features,combined with expert knowledge.In this paper,a feature extraction model Block-gram is proposed to form low-dimensional knowledge-based features from bytecode.First,the metadata is separated and the runtime code is converted into a sequence of opcodes,which are divided into segments based on some instructions(jumps,etc.).Then,scalable Block-gram features,including 4-dimensional block features and 8-dimensional attribute features,are mined for the learning-based model training.Finally,feature contributions are calculated from SHAP values to measure the relationship between our features and the results of the detection model.In addition,six types of vulnerability labels are made on a dataset containing 33,885 contracts,and these knowledge-based features are evaluated using seven state-of-the-art learning algorithms,which show that the average detection latency speeds up 25×to 650×,compared with the features extracted by N-gram,and also can enhance the interpretability of the detection model.展开更多
Banks rely on soft information when assessing loan applications,making it crucial to evaluate the trustworthiness of potential borrowers in order to set loan conditions,even in a legal environment where contractual ri...Banks rely on soft information when assessing loan applications,making it crucial to evaluate the trustworthiness of potential borrowers in order to set loan conditions,even in a legal environment where contractual rights are straightforwardly enforced.Given the common belief that certain personality traits—such as trustworthiness,reliability,loyalty,thriftiness,and stinginess—are more often linked to conservatives(Republicans)than to liberals(Democrats),we investigate whether companies with conservative chief executive officers(CEOs)secure more advantageous loan terms compared to others.Our findings indicate that firms with conservative CEOs are able to negotiate bank loans with lower interest spreads and upfront fees.While we do not observe a direct impact of CEO overconfidence on loan pricing,we reveal that the combined influence of CEO conservatism and overconfidence contributes to our primary findings.Additionally,we discovered that conservative CEOs tend to receive more favorable non-price conditions(fewer covenants)and are less inclined to offer collateral.展开更多
基金Supported by the Research Project of Humanities and Social Sciencesat Universities(08KN020) launched by Guizhou Provincial Education Department
文摘From the perspective of civil subject theory,law of value,comparative law and history of laws,the thesis expounds that the contract on the transfer of the contractual right of rural lands is in nature a civil contract instead of an administrative one.Then it explores the defects in the contract from the viewpoint of legal value goal,contract law and legal sociology,that is,the relevant provisions in Rural Land Contract Law and Explanations of Supreme People's Court about the Issues concerning the Laws Applicable to the Trial of Cases of Disputes over Rural Land Contracting go against the principle of free contracting and run counter to the legal value goal of justice,so they do not achieve good implementing effect.Finally,the thesis demonstrates and makes some practical legislative proposals to perfect the contract system for circulation of the right to operate constructed rural lands,aiming at improving the circulation rate through perfecting the contract of the right to rural land contractual management,solving the disputes in rural lands circulation and safeguarding the legitimate rights of the farmers.
文摘EDITOR＇S NOTE： The Draft Labor Contract Law of the People＇s Republic of China has been completed and was published for soliciting comments on March 20. In a short period of one month, 191,849 pieces of comments and opinions were received. Prior to the promulgation of the law, this reporter interviewed Mr. Guan Huai, a noted Chinese expert in labor law, professor of the Law School of the Renmin University of China and law advisor to the All-China Federation of Trade Unions.
基金supported by the Key Project of Joint Fund of the National Natural Science Foundation of China“Research on Key Technologies and Demonstration Applications for Trusted and Secure Data Circulation and Trading”(U24A20241)the National Natural Science Foundation of China“Research on Trusted Theories and Key Technologies of Data Security Trading Based on Blockchain”(62202118)+4 种基金the Major Scientific and Technological Special Project of Guizhou Province([2024]014)Scientific and Technological Research Projects from the Guizhou Education Department(Qian jiao ji[2023]003)the Hundred-Level Innovative Talent Project of the Guizhou Provincial Science and Technology Department(Qiankehe Platform Talent-GCC[2023]018)the Major Project of Guizhou Province“Research and Application of Key Technologies for Trusted Large Models Oriented to Public Big Data”(Qiankehe Major Project[2024]003)the Guizhou Province Computational Power Network Security Protection Science and Technology Innovation Talent Team(Qiankehe Talent CXTD[2025]029).
文摘As blockchain technology rapidly evolves,smart contracts have seen widespread adoption in financial transactions and beyond.However,the growing prevalence of malicious Ponzi scheme contracts presents serious security threats to blockchain ecosystems.Although numerous detection techniques have been proposed,existing methods suffer from significant limitations,such as class imbalance and insufficient modeling of transaction-related semantic features.To address these challenges,this paper proposes an oversampling-based detection framework for Ponzi smart contracts.We enhance the Adaptive Synthetic Sampling(ADASYN)algorithm by incorporating sample proximity to decision boundaries and ensuring realistic sample distributions.This enhancement facilitates the generation of high-quality minority class samples and effectively mitigates class imbalance.In addition,we design a Contract Transaction Graph(CTG)construction algorithm to preserve key transactional semantics through feature extraction from contract code.A graph neural network(GNN)is then applied for classification.This study employs a publicly available dataset from the XBlock platform,consisting of 318 verified Ponzi contracts and 6498 benign contracts.Sourced from real Ethereum deployments,the dataset reflects diverse application scenarios and captures the varied characteristics of Ponzi schemes.Experimental results demonstrate that our approach achieves an accuracy of 96%,a recall of 92%,and an F1-score of 94%in detecting Ponzi contracts,outperforming state-of-the-art methods.
文摘Due to mobile Internet technology's rapid popularization,the Industrial Internet of Things(IIoT)can be seen everywhere in our daily lives.While IIoT brings us much convenience,a series of security and scalability issues related to permission operations rise to the surface during device communications.Hence,at present,a reliable and dynamic access control management system for IIoT is in urgent need.Up till now,numerous access control architectures have been proposed for IIoT.However,owing to centralized models and heterogeneous devices,security and scalability requirements still cannot be met.In this paper,we offer a smart contract token-based solution for decentralized access control in IIoT systems.Specifically,there are three smart contracts in our system,including the Token Issue Contract(TIC),User Register Contract(URC),and Manage Contract(MC).These three contracts collaboratively supervise and manage various events in IIoT environments.We also utilize the lightweight and post-quantum encryption algorithm-Nth-degree Truncated Polynomial Ring Units(NTRU)to preserve user privacy during the registration process.Subsequently,to evaluate our proposed architecture's performance,we build a prototype platform that connects to the local blockchain.Finally,experiment results show that our scheme has achieved secure and dynamic access control for the IIoT system compared with related research.
基金supported by Fundamental Research Funds for the Central Universities(Nos. CDJXS10170008 and CDJXS10171101)
文摘This paper investigates a sliding-mode model predictive control （MPC） algorithm with auxiliary contractive sliding vector constraint for constrained nonlinear discrete-time systems. By adding contractive constraint into the optimization problem in regular sliding-mode MPC algorithm, the value of the sliding vector is decreased to zero asymptotically, which means that the system state is driven into a vicinity of sliding surface with a certain width. Then, the system state moves along the sliding surface to the equilibrium point within the vicinity. By applying the proposed algorithm, the stability of the closed-loop system is guaranteed. A numerical example of a continuous stirred tank reactor （CSTR） system is given to verify the feasibility and effectiveness of the proposed method.
文摘We examine the economics of royalties in bioprospecting contracts between a pharmaceutical and genetic resource supplier （local）, with an eve to understanding the relative advantages of indexing royalty, payments to gross revenue or net revenue. We show a risk-averse firm facing only production or only cost risks will index royalties to net revenue. When facing both types of risk the choice of royalty type depends on the relative magnitudes of the production and cost risk. In each case, the risk-averse firm chooses the royalty-type that shifts as much risk as possible to the local. Wheat the local is risk neutral the pharmaceutical＇s and local＇s preferences are compatible.If the local is risk averse and there is only one type of risk, it will prefer a gross revenue royalty, and shift as much risk as possible to the firm： here the local and firm preferences are compatible only ifthe firm is risk-neutral. Lastly we show if the firm sets the terms of the contract and both agents are risk averse, the.firm will not likely volunteer to implement the socially optimal royalty arrangement as it prefers to shift as much risk to the loeal, who now also prefers a more certain return, This last outcome is at the heart of the benefit sharing discussionand suggests if risk sharing and equity are a concern in benefit sharing, then the choice of rcyalty type can be an important part of negotiations between pharmaceuticals and locals for the phytochemical from nature for new drug discovery.
文摘surveys the evolution of the contract system of 'responsibility linked to production' in the cooperative economy of China’s socialist agricultural sector and makes a critical analysis of the old model in which labor was deployed in a concentrated way and remuneration paid according to workpoints. He thereby brings to light two specific characteristics of China’s agriculture—the scattered and independent nature of the labor and the unified control and coordination over the process of production by the combination of households—and the two requirements resulting from these. The author holds that the key to the economic nature of the 'contract system of responsibility linked to production' lies in two unique, often puzzling, economic phenomena in the cooperative economy under the system of collective ownership: 1. labor is carried out independently and in a decentralized manner; and 2. remuneration is not based on workpoints but is directly obtained by individuals according to the product. In the process of analyzing these two phenomena, the author differentiates the modes of labor and the relations of production, and clarifies the process of production of the rural contract system’s combination of centralization and decentralization, and the essence of the two-tiered policy. He also formulates the category of 'standard output' to describe a characteristic of the mode of distribution in the rural contract system, that is, the calculation of remuneration according to a standard output. The paper also discusses the rural economy and its development after the institution of the contract system of 'responsibility linked to production' but due to limited space this will be published in a later article.
基金supported in part by the National Natural Science Foundation of China under Grant 61703305in part by the Key Research Program of the Natural Science Foundation of Tianjin under Grant 18JCZDJC38500in part by the Innovative Cooperation Project of Tianjin Scientific and Technological under Grant 18PTZWHZ00090.
文摘With the development of intelligent bionic robots and the improvement of military application,a single robot cannot meet the requirements of the tasks of the current era.The more complex tasks require not only that the robot be able to pass through the field barriers and the amphibious environment,but also that the robot be able to collaborate in a multi-robot system.Consequently,research on the multi-robot control system of spherical amphibious robots is very important.Presently,the main research on amphibious robots is to improve the functions of a single robot,in the absence of the study of the multi-robot control system.Existing systems primarily use a centralized control methodology.Although the transfer of central node can be achieved,there is still a problem of Byzantine fault tolerance in military applications,that is,when the amphibious multi-robot system is invaded by the enemy.The central node may not only fail to accomplish the task,but also lose control of other robots,with severe consequences.To solve the above problems,this paper proposed a decentralized method of spherical amphibious multi-robot control system based on blockchain technology.First,the point-to-point information network based on long range radio technology of low power wide area network was set up,we designed the blockchain system for embedded application environment and the decentralized hardware and software architecture of multi-robot control system.On this basis,the consensus plugin,smart contract and decentralized multi-robot control algorithm were designed to achieve decentralization.The experimental results of consensus of spherical amphibious multi-robot showed the effectiveness of the decentralization.
文摘With the further development of service-oriented,performance-based contracting(PBC)has been widely adopted in industry and manufacturing.However,maintenance optimization problems under PBC have not received enough attention.To further extend the scope of PBC’s application in the field of maintenance optimization,we investigate the condition-based maintenance(CBM)optimization for gamma deteriorating systems under PBC.Considering the repairable single-component system subject to the gamma degradation process,this paper proposes a CBM optimization model to maximize the profit and improve system performance at a relatively low cost under PBC.In the proposed CBM model,the first inspection interval has been considered in order to reduce the inspection frequency and the cost rate.Then,a particle swarm algorithm(PSO)and related solution procedure are presented to solve the multiple decision variables in our proposed model.In the end,a numerical example is provided so as to demonstrate the superiority of the presented model.By comparing the proposed policy with the conventional ones,the superiority of our proposed policy is proved,which can bring more profits to providers and improve performance.Sensitivity analysis is conducted in order to research the effect of corrective maintenance cost and time required for corrective maintenance on optimization policy.A comparative study is given to illustrate the necessity of distinguishing the first inspection interval or not.
基金Partially supported by National Natural Science Foundation of China (No. 10961003)
文摘Iterated function systems （IFS） were introduced by Hutchinson in 1981 as a natural generalization of the well-known Banach contraction principle. In 2010, D. R. Sahu and A. Chakraborty introduced K-Iterated Function System using Kannan mapping which would cover a larger range of mappings. In this paper, following Hutchinson, D. R. Sahu and A. Chakraborty, we present some new iterated function systems by using the so-called generalized contractive mappings, which will also cover a large range of mappings. Our purpose is to prove the existence and uniqueness of attractors for such class of iterated function systems by virtue of a Banach-like fixed point theorem concerning generalized contractive mappings.
基金Project supported by the National Natural Science Foundation of China(Grant No.62363005)the Jiangxi Provincial Natural Science Foundation(Grant Nos.20161BAB212032 and 20232BAB202034)the Science and Technology Research Project of Jiangxi Provincial Department of Education(Grant Nos.GJJ202602 and GJJ202601)。
文摘This paper examines the bipartite consensus problems for the nonlinear multi-agent systems in Lurie dynamics form with cooperative and competitive communication between different agents. Based on the contraction theory, some new conditions for the nonlinear Lurie multi-agent systems reaching bipartite leaderless consensus and bipartite tracking consensus are presented. Compared with the traditional methods, this approach degrades the dimensions of the conditions, eliminates some restrictions of the system matrix, and extends the range of the nonlinear function. Finally, two numerical examples are provided to illustrate the efficiency of our results.
基金supported by the Major Public Welfare Special Fund of Henan Province(No.201300210200)the Major Science and Technology Research Special Fund of Henan Province(No.221100210400).
文摘With the rise of blockchain technology,the security issues of smart contracts have become increasingly critical.Despite the availability of numerous smart contract vulnerability detection tools,many face challenges such as slow updates,usability issues,and limited installation methods.These challenges hinder the adoption and practicality of these tools.This paper examines smart contract vulnerability detection tools from 2016 to 2023,sourced from the Web of Science(WOS)and Google Scholar.By systematically collecting,screening,and synthesizing relevant research,38 open-source tools that provide installation methods were selected for further investigation.From a developer’s perspective,this paper offers a comprehensive survey of these 38 open-source tools,discussing their operating principles,installation methods,environmental dependencies,update frequencies,and installation challenges.Based on this,we propose an Ethereum smart contract vulnerability detection framework.This framework enables developers to easily utilize various detection tools and accurately analyze contract security issues.To validate the framework’s stability,over 1700 h of testing were conducted.Additionally,a comprehensive performance test was performed on the mainstream detection tools integrated within the framework,assessing their hardware requirements and vulnerability detection coverage.Experimental results indicate that the Slither tool demonstrates satisfactory performance in terms of system resource consumption and vulnerability detection coverage.This study represents the first performance evaluation of testing tools in this domain,providing significant reference value.
基金supported by the Key Clinical Projects of Peking University Third Hospital(grant no.BYSYZD2019013)。
文摘Background:This study aimed to review treatments and evaluate the aesthetic outcomes,complications,and reoperation rates regarding surgical correction for a postoperative contracted nose.Methods:PubMed,MEDLINE,and Embase databases were searched for studies detailing aesthetic outcomes and complications of surgical correction of a contracted nose.Surgical procedures,adjuvant treatment,outcomes,and complications were synthesized and analyzed.Results:Nine articles encompassing 376 patients were included in the systematic review,and six articles(198 participants)were included in the meta-analysis.The most frequently used graft material was the autologous rib cartilage(61.1%).Surgical procedures were heterogeneous in these studies.The nasolabial angle reduced by 9.52°(95%confidence interval(CI):(-11.95,-7.09),P<0.0001),and the nasal length increased significantly(standardized mean difference(SMD)=2.25,95%CI:(1.26,2.23),P<0.00001).However,the evidence was insufficient to determine a significant change in the columellar-labial angle(SMD=-0.95,95%CI:(-2.19,0.29),P=0.13)and columellar-lobular angle(SMD=2.39,95%CI:(-1.20,5.97),P=0.19).Aesthetic dissatisfaction(12.5%)and infection(4.5%)were the most commonly reported complications.Reoperation was performed in 5.3%of patients.Conclusion:Surgical correction can increase the nasal length,reduce the nasolabial angle,and have a low reoperation rate.No significant improvement in the columellar-labial or columellar-lobular angle was observed.
文摘We developed an eccentric contraction induced electrical stimulation (ES) training system. The purpose of this study was to investigate whether the eccentric contraction induced ES enhance the knee extension torque compared with typical ES. Twenty-two young untrained men (age: 23 ± 3 years) in the acute response trial (single training) and seven untrained men in the long period training trial (for 6 weeks) were studied. We measured muscle thickness and knee extension torque evoked by ES with eccentric contraction training system (ES + ECC) or ES alone for the quadriceps muscle of men. The levels of pain and discomfort were evaluated using numeric rating scale (NRS) and heart rate variability. The knee extension torque of ES + ECC was higher than that of ES alone in the acute response trial. There were no significant differences in the levels of pain and discomfort between ES and ES + ECC. Additionally, ES + ECC training for 6 weeks was effective on the quadriceps muscle thickness and knee extension torque. In contrast, the ES alone training failed to increase muscle thickness and knee extension torque. These results suggest that eccentric contraction induced ES would have the potential to become an effective intervention to promote muscle strengthening.
文摘The study was conducted with the aim of exploring the barriers to the adoption of BOT contract systems for infrastructural development of technical universities in Ghana. In an empirical questionnaire survey with professionals and experts in the construction and education sector, the respondents were invited to rate their perception on the barriers to the adoption of the BOT contracts systems. An interview session to satisfy ways of adopting the BOT contracts for infrastructural development in technical universities was conducted with selected professionals. The study revealed that the major barriers to the adoption of the BOT contract system are: delays in approval, corruption, reliability and credit worthiness of entities and expropriation. The study suggested that detailed policy or framework for implementing BOT contracts;proper planning by technical universities;and adequate protection for lenders is required for successful BOT implementation. Therefore there is a need to explore this concept, using adequate policy initiatives, proper measures and support from government to improve on the proper implementation of the BOT contracts in Technical Universities in Ghana.
文摘Based on the applicable principle of liquidated damages in ＂contract law＂, based on the improvement of the system, the article first analyzes the status quo of the development of the default system and secondly puts forward some suggestions for improvement. The final purpose is to perfect the liquidated damages system with the Contract Law, in a bid to enhance the fairness of liquidated damages.
文摘The realty(real estate)management of ownership of buildings includes the owner(homeowner)entrust-management and the owner self-management,the former through the way of realty service contracts,the latter through the resolution of the owners’assembly and the owners’committee.The legal disputes of realty service contracts involve balancing interests among the realty service enterprise,individual owner,and all the owners.We should use dynamic balancing of the interests of the three parties to implement the interests of the win-win cooperation rather than the interests of the trade-off of“all or nothing.”The realty service contract is similar to the entrustment contract,both of which are based on the owners’entrustment.The duty to provide realty service is not simply equivalent to fiduciary duty.The realty service contract has the essence of both behavior debt and result debt.For the former,the general provisions of the entrustment contract can be referred to,and for the latter,the general provisions of the contract for work can be referred to.In view of the group characteristics of the realty service contract,owners have no right to terminate the realty service contract at any time but should obey the principle of due process and take the majority mechanism to make a dismissal resolution resolution.The resolutions and management stipulations worked out by the owners’assembly in a majority mechanism,both of which belong to resolution behavior and are legal tools of the owners’autonomy,shall be binding on all the owners.The relationship between the owner,the owner’s assembly,and the owner’s committee is similar to the fiduciary relationship.If the decision made by the owners’assembly or the owners’committee and the management stipulation infringes upon the legal rights and interests of the owners,the injured owner has the right to revocation litigation.At present,residential commodity owners have a relatively low degree of autonomy in China,and legal disputes over realty services are frequent.In the future,we need to perfect the legal incentive and constraint measures,and stimulate the vitality of owner autonomy to promote better implementation of the owner self-management and owner entrust-management.
基金the National Natural Science Foundations of China (grant No. 61802436 and No. 61702550)he National Key Research and Development Plan (grant No. 2018YFB0803603 and No. 2016YFB0501901).
文摘The current Internet web trust system is based on the traditional PKI system, to achieve the purpose of secure communication through the trusted third party. However, with the increase of network nodes, various problems appear in the centralization system of public key infrastructure (PKI). In recent years, in addition to cryptographic problems, attacks against PKI have focused on the single point of failure of certificate authority (CA). Although there are many reasons for a single point of failure, the purpose of the attack is to invalidate the CA. Thus a distributed authentication system is explored to provide a feasible solution to develop distributed PKI with the rise of the blockchain. Due to the automation and economic penalties of smart contracts, a PKI system is proposed based on smart contracts. The certificate chain was constructed in the blockchain, and a mechanism was adopted for auditing access to CA nodes in the blockchain. Experimental results show that security requirements of CA are met in this system.
基金partially supported by the National Natural Science Foundation (62272248)the Open Project Fund of State Key Laboratory of Computer Architecture,Institute of Computing Technology,Chinese Academy of Sciences (CARCHA202108,CARCH201905)+1 种基金the Natural Science Foundation of Tianjin (20JCZDJC00610)Sponsored by Zhejiang Lab (2021KF0AB04)。
文摘Smart contracts are widely used on the blockchain to implement complex transactions,such as decentralized applications on Ethereum.Effective vulnerability detection of large-scale smart contracts is critical,as attacks on smart contracts often cause huge economic losses.Since it is difficult to repair and update smart contracts,it is necessary to find the vulnerabilities before they are deployed.However,code analysis,which requires traversal paths,and learning methods,which require many features to be trained,are too time-consuming to detect large-scale on-chain contracts.Learning-based methods will obtain detection models from a feature space compared to code analysis methods such as symbol execution.But the existing features lack the interpretability of the detection results and training model,even worse,the large-scale feature space also affects the efficiency of detection.This paper focuses on improving the detection efficiency by reducing the dimension of the features,combined with expert knowledge.In this paper,a feature extraction model Block-gram is proposed to form low-dimensional knowledge-based features from bytecode.First,the metadata is separated and the runtime code is converted into a sequence of opcodes,which are divided into segments based on some instructions(jumps,etc.).Then,scalable Block-gram features,including 4-dimensional block features and 8-dimensional attribute features,are mined for the learning-based model training.Finally,feature contributions are calculated from SHAP values to measure the relationship between our features and the results of the detection model.In addition,six types of vulnerability labels are made on a dataset containing 33,885 contracts,and these knowledge-based features are evaluated using seven state-of-the-art learning algorithms,which show that the average detection latency speeds up 25×to 650×,compared with the features extracted by N-gram,and also can enhance the interpretability of the detection model.
文摘Banks rely on soft information when assessing loan applications,making it crucial to evaluate the trustworthiness of potential borrowers in order to set loan conditions,even in a legal environment where contractual rights are straightforwardly enforced.Given the common belief that certain personality traits—such as trustworthiness,reliability,loyalty,thriftiness,and stinginess—are more often linked to conservatives(Republicans)than to liberals(Democrats),we investigate whether companies with conservative chief executive officers(CEOs)secure more advantageous loan terms compared to others.Our findings indicate that firms with conservative CEOs are able to negotiate bank loans with lower interest spreads and upfront fees.While we do not observe a direct impact of CEO overconfidence on loan pricing,we reveal that the combined influence of CEO conservatism and overconfidence contributes to our primary findings.Additionally,we discovered that conservative CEOs tend to receive more favorable non-price conditions(fewer covenants)and are less inclined to offer collateral.
