Mitigating Blackhole and Greyhole Routing Attacks in Vehicular Ad Hoc Networks Using Blockchain Based Smart Contracts

The rapid increase in vehicle traffic volume in modern societies has raised the need to develop innovative solutions to reduce traffic congestion and enhance traffic management efficiency.Revolutionary advanced technology,such as Intelligent Transportation Systems(ITS),enables improved traffic management,helps eliminate congestion,and supports a safer environment.ITS provides real-time information on vehicle traffic and transportation systems that can improve decision-making for road users.However,ITS suffers from routing issues at the network layer when utilising Vehicular Ad Hoc Networks(VANETs).This is because each vehicle plays the role of a router in this network,which leads to a complex vehicle communication network,causing issues such as repeated link breakages between vehicles resulting from the mobility of the network and rapid topological variation.This may lead to loss or delay in packet transmissions;this weakness can be exploited in routing attacks,such as black-hole and gray-hole attacks,that threaten the availability of ITS services.In this paper,a Blockchain-based smart contracts model is proposed to offer convenient and comprehensive security mechanisms,enhancing the trustworthiness between vehicles.Self-Classification Blockchain-Based Contracts(SCBC)and Voting-Classification Blockchain-Based Contracts(VCBC)are utilised in the proposed protocol.The results show that VCBC succeeds in attaining better results in PDR and TP performance even in the presence of Blackhole and Grayhole attacks.

Strategic Contracting for Software Upgrade Outsourcing in Industry 4.0

The advent of Industry 4.0 has compelled businesses to adopt digital approaches that combine software toenhance production efficiency. In this rapidly evolving market, software development is an ongoing process thatmust be tailored to meet the dynamic needs of enterprises. However, internal research and development can beprohibitively expensive, driving many enterprises to outsource software development and upgrades to externalservice providers. This paper presents a software upgrade outsourcing model for enterprises and service providersthat accounts for the impact of market fluctuations on software adaptability. To mitigate the risk of adverseselection due to asymmetric information about the service provider’s cost and asymmetric information aboutthe enterprise’s revenues, we propose pay-per-time and revenue-sharing contracts in two distinct informationasymmetry scenarios. These two contracts specify the time and transfer payments for software upgrades. Througha comparative analysis of the optimal solutions under the two contracts and centralized decision-making withfull-information, we examine the characteristics of the solutions under two information asymmetry scenarios andanalyze the incentive effects of the two contracts on the various stakeholders. Overall, our study offers valuableinsights for firms seeking to optimize their outsourcing strategies and maximize their returns on investment insoftware upgrades.

Research on optimal intelligent routing algorithm for IoV with machine learning and smart contract

The huge increase in the communication network rate has made the application fields and scenarios for vehicular ad hoc networks more abundant and diversified and proposed more requirements for the efficiency and quality of data transmission.To improve the limited communication distance and poor communication quality of the Internet of Vehicles(IoV),an optimal intelligent routing algorithm is proposed in this paper.Combined multiweight decision algorithm with the greedy perimeter stateless routing protocol,designed and evaluated standardized function for link stability.Linear additive weighting is used to optimize link stability and distance to improve the packet delivery rate of the IoV.The blockchain system is used as the storage structure for relay data,and the smart contract incentive algorithm based on machine learning is used to encourage relay vehicles to provide more communication bandwidth for data packet transmission.The proposed scheme is simulated and analyzed under different scenarios and different parameters.The experimental results demonstrate that the proposed scheme can effectively reduce the packet loss rate and improve system performance.

Framing Education-Civicness-Social Contract Nexus in Africa? The Case of South Sudan

This article attempts to position education not only in the peacebuilding debate but also in the larger good governance debate about what makes a resilient social contract.We subscribe in this paper to a theoretical perspective that attributes the driver of civil wars to governance deficit that is manifested in absence of resilient social contract in terms of sustained agreement between citizens and state.We then ask the key question of whether and how education is linked to a resilient social contract.We found a wealth of evidence linking education and peacebuilding,and education and civicness,but a gap exists in the literature about the link between education and social contract.On the basis of a thorough review of theory and research on education,civicness,and social contract,we develop a theoretical framework to conceptually frame the nexus between education,civicness,resilient social contract,and sustainable peace.This framework is founded on the theory of state formation.Applying this framework to the case of South Sudan,we found that education through civicness makes students become key political stakeholders and more likely nurture a resilient social contract,which in turn sustains peace.The very low level of educated population in South Sudan might have contributed,among other factors,to limited demand for good governance that contributes to governance deficit,which perpetuates poor state-society relations,ineffective and exclusive institutions,and erosion of social cohesion,and interpersonal trust,factors central to resilient social contract.

Bipartite consensus problems of Lurie multi-agent systems over signed graphs: A contraction approach

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.

Preserving Data Secrecy and Integrity for Cloud Storage Using Smart Contracts and Cryptographic Primitives

Cloud computing has emerged as a viable alternative to traditional computing infrastructures,offering various benefits.However,the adoption of cloud storage poses significant risks to data secrecy and integrity.This article presents an effective mechanism to preserve the secrecy and integrity of data stored on the public cloud by leveraging blockchain technology,smart contracts,and cryptographic primitives.The proposed approach utilizes a Solidity-based smart contract as an auditor for maintaining and verifying the integrity of outsourced data.To preserve data secrecy,symmetric encryption systems are employed to encrypt user data before outsourcing it.An extensive performance analysis is conducted to illustrate the efficiency of the proposed mechanism.Additionally,a rigorous assessment is conducted to ensure that the developed smart contract is free from vulnerabilities and to measure its associated running costs.The security analysis of the proposed system confirms that our approach can securely maintain the confidentiality and integrity of cloud storage,even in the presence of malicious entities.The proposed mechanism contributes to enhancing data security in cloud computing environments and can be used as a foundation for developing more secure cloud storage systems.

Smart Contract Vulnerability Detection Method Based on Feature Graph and Multiple Attention Mechanisms

The fast-paced development of blockchain technology is evident.Yet,the security concerns of smart contracts represent a significant challenge to the stability and dependability of the entire blockchain ecosystem.Conventional smart contract vulnerability detection primarily relies on static analysis tools,which are less efficient and accurate.Although deep learning methods have improved detection efficiency,they are unable to fully utilize the static relationships within contracts.Therefore,we have adopted the advantages of the above two methods,combining feature extraction mode of tools with deep learning techniques.Firstly,we have constructed corresponding feature extraction mode for different vulnerabilities,which are used to extract feature graphs from the source code of smart contracts.Then,the node features in feature graphs are fed into a graph convolutional neural network for training,and the edge features are processed using a method that combines attentionmechanismwith gated units.Ultimately,the revised node features and edge features are concatenated through amulti-head attentionmechanism.The result of the splicing is a global representation of the entire feature graph.Our method was tested on three types of data:Timestamp vulnerabilities,reentrancy vulnerabilities,and access control vulnerabilities,where the F1 score of our method reaches 84.63%,92.55%,and 61.36%.The results indicate that our method surpasses most others in detecting smart contract vulnerabilities.

A Systematic Review and Performance Evaluation of Open-Source Tools for Smart Contract Vulnerability Detection

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.

A Review of Deep Learning-Based Vulnerability Detection Tools for Ethernet Smart Contracts

In recent years,the number of smart contracts deployed on blockchain has exploded.However,the issue of vulnerability has caused incalculable losses.Due to the irreversible and immutability of smart contracts,vulnerability detection has become particularly important.With the popular use of neural network model,there has been a growing utilization of deep learning-based methods and tools for the identification of vulnerabilities within smart contracts.This paper commences by providing a succinct overview of prevalent categories of vulnerabilities found in smart contracts.Subsequently,it categorizes and presents an overview of contemporary deep learning-based tools developed for smart contract detection.These tools are categorized based on their open-source status,the data format and the type of feature extraction they employ.Then we conduct a comprehensive comparative analysis of these tools,selecting representative tools for experimental validation and comparing them with traditional tools in terms of detection coverage and accuracy.Finally,Based on the insights gained from the experimental results and the current state of research in the field of smart contract vulnerability detection tools,we suppose to provide a reference standard for developers of contract vulnerability detection tools.Meanwhile,forward-looking research directions are also proposed for deep learning-based smart contract vulnerability detection.

Design and pricing of maintenance service contract based on Nash non-cooperative game approach

Nowadays manufacturers are facing fierce challenge.Apart from the products,providing customers with multiple maintenance options in the service contract becomes more popular,since it can help to improve customer satisfaction,and ultimately promote sales and maximize profit for the manufacturer.By considering the combinations of corrective maintenance and preventive maintenance,totally three types of maintenance service contracts are designed.Moreover,attractive incentive and penalty mechanisms are adopted in the contracts.On this basis,Nash non-cooperative game is applied to analyze the revenue for both the manufacturer and customers,and so as to optimize the pricing mechanism of maintenance service contract and achieve a win-win situation.Numerical experiments are conducted.The results show that by taking into account the incentive and penalty mechanisms,the revenue can be improved for both the customers and manufacturer.Moreover,with the increase of repair rate and improvement factor in the preventive maintenance,the revenue will increase gradually for both the parties.

Contract Mechanism of Water Environment Regulation for Small and Medium Sized Enterprises Based on Optimal Control Theory

The small and scattered enterprise pattern in the county economy has formed numerous sporadic pollution sources, hindering the centralized treatment of the water environment, increasing the cost and difficulty of treatment. How enterprises can make reasonable decisions on their water environment behavior based on the external environment and their own factors is of great significance for scientifically and effectively designing water environment regulation mechanisms. Based on optimal control theory, this study investigates the design of contractual mechanisms for water environmental regulation for small and medium-sized enterprises. The enterprise is regarded as an independent economic entity that can adopt optimal control strategies to maximize its own interests. Based on the participation of multiple subjects including the government, enterprises, and the public, an optimal control strategy model for enterprises under contractual water environmental regulation is constructed using optimal control theory, and a method for calculating the amount of unit pollutant penalties is derived. The water pollutant treatment cost data of a paper company is selected to conduct empirical numerical analysis on the model. The results show that the increase in the probability of government regulation and public participation, as well as the decrease in local government protection for enterprises, can achieve the same regulatory effect while reducing the number of administrative penalties per unit. Finally, the implementation process of contractual water environmental regulation for small and medium-sized enterprises is designed.

A secure spectrum auction scheme without the trusted party based on the smart contract

With the development of communication 5G networks and technologies,spectrum resources are increasingly scarce.The scarcity of the spectrum resource makes market-driven spectrum auction become an important means of spectrum allocation,and due to the complexity of the network environment,the security of spectrum auctions can not be ignored.Most existing secure spectrum auction schemes introduce a semi-honest agent to complete spectrum auction.However,the hypothetical semi-honest model does not guarantee the security of spectnim auction in the actual application scenario,which may lead to potential security threats:the agent may reveal the privacy of bidders,agent or auctioneer may collude with the bidder to manipulate the spectrum auction,and so on.In this paper,a secure spectrum auction scheme without a trusted party is proposed based on the smart contract technology,and the smart contract written into the blockchain replaces the traditional semi-honest agent to cooperate with the auctioneer server to complete the auction.In order to ensure the security of our scheme,a secure spectrum auction protocol is designed,in which the Software Guard Extensions(SGX)technology and Paillier cryptosystem are used to protect the privacy of bidders.Public verification is provided in our protocol by using extensive Pedersen commitment,which prevents the auctioneer server and the bidder from colluding with each other and verifies group bid sum values.Finally,the security analysis is given to propose several types of attacks that can be defended.Besides,theoretical analysis and simulation experiments of our protocol are also provided.

Mechanical Proofs about BW Multi-Party Contract Signing Protocol

We report on the verification of a multi-party contract signing protocol described by Baum-Waidner and Waidner （BW）. Based on Paulson＇s inductive approach, we give the protocol model that includes infinitely many signatories and contract texts signing simuhaneously. We consider composite attacks of the dishonest signatory and the external intruder, formalize cryptographic primitives and protocol arithmetic including attack model, show formal description of key distribution, and prove signature key secrecy theorems and fairness property theorems of the BW protocol using the interactive theorem prover Isabelle/HOL.

A Probe into the Mortgage Rates of Land Contract Management Rights Based on Unified Annual Output Value

The mortgage of land contract management rights has launched a pilot project in Ningxia,Hubei,Henan,Guizhou,Chongqing and other provinces,municipalities and autonomous regions,which provides a good solution to the problem of funds for rural development and plays a huge role in promoting local rural economic development.In the mortgage financing of land contract management rights implemented in various regions,how to determine a scientific,accurate and reasonable mortgage rate of land contract management rights becomes a difficulty troubling the mortgage financing of land.On the basis of unified annual output value of land,this article uses survey method,income capitalization method,and comparison method to analyze the value of land contract management rights,and finally determine the mortgage rates of land contract management rights.

Electronic Auction Scheme Based on Smart Contract and IPFS

Sealed-bid auctions are a vital transaction tool in the e-commerce field.Traditional centralized auction schemes typically result in severe threats to data integrity,information transparency,and traceability owing to their excessive reliance on third parties,and blockchain-based auction schemes generally suffer from high storage costs and are deficient in functional and architectural design.To solve these problems,this study presents a sealed-bid auction scheme that removes the third-party based on an Ethereum smart contract,ensuring data integrity,openness,and transparency in the execution process.The commitment mechanism and distributed storage system help to significantly reduce the user’s storage cost and protect the privacy of user bids.For the functional design,this study introduces a fulltext-retrieval and dispute-processing module for commodities,which reduces the defects existing in the functional module design of existing auction systems.Furthermore,a prototype auction system on the Ethereum test chain is built to validate the proposed scheme.Experiments show that compared with traditional storage methods,indirect storage based on a distributed storage system of texts and images can reduce the storage cost by at least 50%while ensuring data integrity.Finally,the gas cost at each stage of the auction scheme and the time required for the full-text retrieval of products are recorded to evaluate the scheme performance and analyze the test results.

Effect of Knowledge about Workers' Psychological Contract Imbalance on Organizational Performance

Knowledge-based employees are the inexhaustible motive force for the sustainable development of modern enterprises. Being consistent with the psychological expectation of knowledge-based employees is conducive to stimulating the intrinsic motivation of knowledge-based employees and promoting the innovation performance of enterprises. Based on 175 valid questionnaires,the analysis shows that the knowledge about employees' psychological contract can be divided into two-dimension, transactional or relational dimension. Both of them are independent to each other.The correlation analysis shows that the transactional psychological contract and relational psychological contract have positive correlation with team performance and organization performance.At the same time, the team performance and organization performance have positive correlation. Regression analysis shows that compared with relational psychological contract,transactional psychological contract can promote team performance and organizational performance more effectively. Both two psychological contracts can mediate the organizational performance by virtue of team performance.

Synthetic Evaluation of Contractor's Performance in Outcome-Based Contract

Outcome-based contract( OBC) is a kind of contracting mechanism,which allows the customer to pay only when the firm has delivered outcomes,rather than activities and tasks involved. To achieve the higher demand of the delivering outcome of the contract,the evaluation of contractor's performance was focused on. A reasonable and objective contractor performance evaluation system is constructed by considering various uncertainties. The set pair theory is used to analyze the four-element connection of quality of service contractors. It aims to provide a theoretical basis for the decisionmaker to make confirmation of the equipment contractor who has a better performance and development trend.

Myofiber Permeability and Force Production of Rat Muscles Following Eccentric Contractions: The Repeated Bout Effect Depends on the Interval

Past eccentric contraction (ECC)-induced muscle injury reduces the severity of symptoms of subsequent muscle injury;this phenomenon is known as a repeated bout effect (RBE). It has been reported that increases in the duration of the interval between the first and second bouts are linked to weakening of the RBE. However, the histology following the attenuation of the RBE remains unclear. We examined the sustained effects of the second bout with regard to myofiber permeability and muscle force. Sixty-four male rats were randomly assigned to eight groups that varied in the number of exercise sessions and the duration of the interval between the first and second bouts: the non-ECC (Control);the single-injury (Post 1st bout);groups that were allowed to recover for 1, 2, and 4 weeks after a single injury (Pre 2nd bout_1w, Pre 2nd bout_2w, and Pre 2nd bout_4w);and groups that were subjected to second injuries 1, 2, and 4 weeks after the first (Post 2nd bout_1w, Post 2nd bout_2w, and Post 2nd bout_4w). The tibialis anterior was electrically stimulated in each ECC group. Twenty-four hours before muscle sampling, Evans blue dye (EBD) (a marker of myofiber damage) was administered. The maximal isometric contraction tension was measured immediately before sampling. The number of EBD-positive (+) fibers was determined via histological analysis. An RBE was revealed by functional examination at the 1- and 2-week and histological examination at the 1-, 2-, and 4-week time points (P < 0.05). In terms of myofiber permeability, prolongation of the interval before the second bout weakened this effect (P < 0.05). Experiments with 1-, 2-, and 4-week intervals indicated that prolongation of the interval before the second bout weakened the RBE with regard to myofiber permeability.

Efficacy of Danshen Injection Combined with Phosphocreatine Disodium in Treating Frequent Premature Contractions during Pregnancy and Its Effects on Maternal and Infant Outcomes

[Objectives]To explore the efficacy of Danshen Injection combined with phosphocreatine disodium in treating frequent premature contractions during pregnancy and its effect on maternal and infant outcomes.[Methods]A total of 200 pregnant women with normal pregnancy and frequent premature contractions who were treated in the outpatient department of internal medicine in Women and Children's Hospital of Hubei Province and Xinzhou District People's Hospital of Wuhan Central Hospital during September 2015 and October 2018 were selected and randomly divided into the control group and observation group,100 cases for each group.The observation group was treated with Danshen Injection combined with phosphocreatine disodium,and the control group was treated with phosphocreatine disodium alone.The course of treatment in both groups was one week.During the treatment,the changes of heart rate,heart rhythm,electrocardiogram and 24-h dynamic electrocardiogram(DCG)of both groups were observed.[Results]After treatment,the clinical efficacy of the observation group was better than that of the control group,and the difference was statistically significant(P<0.01).There were no adverse drug reactions in both groups.However,in the control group,non-sustained ventricular tachycardia(NSVT)was found in 24-h dynamic electrocardiogram(DCG)of 2 pregnant women with premature ventricular contraction.The pregnancy process was smooth,with full-term natural delivery and no fetal malformation.There was no significant difference in gestational age and neonatal weight between the two groups(P>0.05).However,there was a statistically significant difference in Apgar score between the two groups(P<0.05).During the 6-month postpartum follow-up,the mother and child were unharmed,and examination of repeated electrocardiograms showed that the conditions were normal.[Conclusions]Danshen Injection combined with phosphocreatine disodium has better efficacy in the treatment of frequent premature contractions during pregnancy and the maternal and infant outcomes than the treatment with phosphocreatine disodium alone,and it has good safety and can prevent premature contractions from progressing to tachyarrhythmias.

Dermis-fat graft for contracted socket reconstruction in an indigenous black population, Southwestern Nigeria

The purpose of this case series is to report the indications for dermis-fat grafting and the outcome of treatment in orbital soft tissue contraction among patients in a tertiary center. It is a retrospective, consecutive, interventional case series where all patients with orbital soft tissue contraction who had dermis-fat grafting were studied. All nine patients in our series underwent secondary dermis-fat grafting for orbital soft tissue reconstruction. The major cause for contracted socket was surgical eye removal following trauma. Eight of nine patients had no orbital implants inserted at the time of primary eye removal and eight patients have had failed orbital reconstructive procedures. Satisfactory cosmetic results were reported in all patients post-operatively. Dermis-fat grafting for contracted socket reconstruction was found to give satisfactory cosmetic results in our studied population.