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
The Book on Contracts of the Civil Code does not recognize"intellectual property contracts"as nominate contracts.Owing to both substantive and structural shortcomings,the Chapter on Technology Contracts fall...The Book on Contracts of the Civil Code does not recognize"intellectual property contracts"as nominate contracts.Owing to both substantive and structural shortcomings,the Chapter on Technology Contracts falls short of providing comprehensive regulation of transactions involving intellectual property,and its Article 876 linking clause has given rise to legal controversies over application by reference and priority of application.There is therefore an urgent need to recognize intellectual property contracts as a nominate category.The rules on such contracts that are dispersed across standalone intellectual property statutes,specialized regulations,adjudicated cases,and judicial interpretations have already produced decodification and should be integrated in the course of enacting the Intellectual Property Code,so as to achieve the recodification of contracts concerning intellectual property.Specifically,the Chapter on Contracts should consist of two parts,General Provisions and Nominate Contracts,to articulate the common features and specific rules of the various contract types while confirming the applicability of the General Provisions in the Book on Contracts.In this way,systemic disorder from mechanically adding nominate contracts to the Civil Code and unnecessary complexity from creating a separate sectoral contract code can both be avoided,and the status of the Book on Contracts as the basic law in the field of contract can be preserved.展开更多
This article explores the characteristics of data resources from the perspective of production factors,analyzes the demand for trustworthy circulation technology,designs a fusion architecture and related solutions,inc...This article explores the characteristics of data resources from the perspective of production factors,analyzes the demand for trustworthy circulation technology,designs a fusion architecture and related solutions,including multi-party data intersection calculation,distributed machine learning,etc.It also compares performance differences,conducts formal verification,points out the value and limitations of architecture innovation,and looks forward to future opportunities.展开更多
With the rapid proliferation of Internet ofThings(IoT)devices,ensuring their communication security has become increasingly important.Blockchain and smart contract technologies,with their decentralized nature,provide ...With the rapid proliferation of Internet ofThings(IoT)devices,ensuring their communication security has become increasingly important.Blockchain and smart contract technologies,with their decentralized nature,provide strong security guarantees for IoT.However,at the same time,smart contracts themselves face numerous security challenges,among which reentrancy vulnerabilities are particularly prominent.Existing detection tools for reentrancy vulnerabilities often suffer from high false positive and false negative rates due to their reliance on identifying patterns related to specific transfer functions.To address these limitations,this paper proposes a novel detection method that combines pattern matching with deep learning.Specifically,we carefully identify and define three common patterns of reentrancy vulnerabilities in smart contracts.Then,we extract key vulnerability features based on these patterns.Furthermore,we employ a Graph Attention Neural Network to extract graph embedding features from the contract graph,capturing the complex relationships between different components of the contract.Finally,we use an attention mechanism to fuse these two sets of feature information,enhancing the weights of effective information and suppressing irrelevant information,thereby significantly improving the accuracy and robustness of vulnerability detection.Experimental results demonstrate that our proposed method outperforms existing state-ofthe-art techniques,achieving a 3.88%improvement in accuracy compared to the latest vulnerability detection model AME(Attentive Multi-Encoder Network).This indicates that our method effectively reduces false positives and false negatives,significantly enhancing the security and reliability of smart contracts in the evolving IoT ecosystem.展开更多
The challenge for supply chain management is to create appropriate supply chain contracts so as to optimize the system performance. To examine the role of asymmetric information in a two-echelon supply chain system an...The challenge for supply chain management is to create appropriate supply chain contracts so as to optimize the system performance. To examine the role of asymmetric information in a two-echelon supply chain system and derive supply chain contracts to deal with existing asymmetric information, a two level supply chain model including one Supplier and one retailer under the demand of price elasticity is developed. By using the principalagent principle and the optimal control theory, three types of supply chain contract, i. e. , a wholesale pricing contract, a two-parameter linear and a two-parameter nonlinear contracts are obtained. In these contracts, the Supplier has asymmetric information about the retailer cost structure. Simulation results show that the two-parameter contracts are more effective strategies to achieve supply chain coordination.展开更多
A majority of contracts will use many prepositions and prepositional phrases to reflect their preciseness which cause the treaty wording complicated and hard to understand. This paper tends to demonstrate the characte...A majority of contracts will use many prepositions and prepositional phrases to reflect their preciseness which cause the treaty wording complicated and hard to understand. This paper tends to demonstrate the characteristics of the prepositions and prepositional phrases used in business English contracts and explore the translation strategies used in translating the features of the prepositions and the prepositional phrases in business English contracts. The findings of this paper can provide a reference for the majority of the trade workers, which can help them accurately and effectively draft or translate a contract and avoid unnecessary disputes.展开更多
This paper tries to demonstrate that the principle of the risk allocation based on the balance is the most effective way to resolve the risk allocation problems of public-private partnership （PPP） contracts and pres...This paper tries to demonstrate that the principle of the risk allocation based on the balance is the most effective way to resolve the risk allocation problems of public-private partnership （PPP） contracts and presents suggestions how to carry out this principle. For PPP projects, it is necessary to set up a workable and commercially viable risk sharing mechanism to satisfy the different interests and the objectives of both the public sector and the private sector. An effective risk allocation mechanism is not only an important part in preparing project documents, but also an essential part in the success of PPP contracts. Risk allocation can be represented in a risk matrix. The more balanced the risk allocation is, the lower the risk degree of PPP contracts is. Therefore, the most effective risk allocation of PPP contracts is that the public sector and the private sector take part in risk management together in all the stages of the project and allocate the balanced risks. The outcomes of this paper can be used by both the public sector and the private sector to make a good choice of the PPP contract form.展开更多
Production sharing contracts have been used in the development of China’s offshore petroleum resources since 1982, but the mechanism in which the fiscal terms impact project economics is complicated and not well unde...Production sharing contracts have been used in the development of China’s offshore petroleum resources since 1982, but the mechanism in which the fiscal terms impact project economics is complicated and not well understood. The purpose of this paper is to model China’s offshore production sharing contracts using a probabilistic approach. Cash flows and economic indicators are used for a typical offshore oilfield development, and meta-models are constructed to analyze the basic features of the fiscal system. Applications of the models in contract negotiation are discussed.展开更多
In supply chain management,an important research direction is to coordinate the supply chain through introducing flexible contracts.A supply chain contract is flexible if it can satisfy two conditions at the same time...In supply chain management,an important research direction is to coordinate the supply chain through introducing flexible contracts.A supply chain contract is flexible if it can satisfy two conditions at the same time:the supply chain is coordinated,and the total profit of the supply chain can be arbitrarily divided between the supply chain members.This paper puts out two contracts,a flexible return contract and a flexible wholesale price discount contract.In contrast to many of literature,the supply chain contracts with an endogenous wholesale price is specifically considered,and a detailed sensitivity analysis of the contract parameters is given.The paper also discusses the application of the contract in vendor-managed inventory(VMI)mode.The results show that the supply chain's performance is improved after introducing above contracts.All the findings are illustrated by numerical examples.展开更多
The offshore pipeline network in the U.S. Gulf of Mexico is the largest and most transparent system in the world. A review of deepwater projects in the region provides insight into construction cost and installation m...The offshore pipeline network in the U.S. Gulf of Mexico is the largest and most transparent system in the world. A review of deepwater projects in the region provides insight into construction cost and installation methods and the evolution of contract strategies. Pipeline projects are identified as export systems, infield flowline systems, and combined export and infield systems, and three dozen deepwater pipeline installations from 1980–2014 are described based on Offshore Technology Conference(OTC) and Society of Petroleum Engineers(SPE) industry publications and press release data. Export lines and infield flowlines are equally represented and many projects used a combination of J-lay, S-lay and reel methods with rigid steel, flexible line, and pipe-in-pipe systems. The average 2014 inflation-adjusted cost for pipeline projects based on OTC/SPE publications was $2.76 million/mi and ranged from $520 000/mi to $12.94 million/mi. High cost pipelines tend to be short segments or specialized pipeline. Excluding the two cost endpoints, the majority of projects ranged from $1 to $6 million/mi. The average inflation-adjusted cost to install deepwater pipelines in the U.S. Gulf of Mexico based on available public data is estimated at $3.1 million/mi.展开更多
In this paper,we deal with questions related to blockchains in complex Internet of Things(IoT)-based ecosystems.Such ecosystems are typically composed of IoT devices,edge devices,cloud computing software services,as w...In this paper,we deal with questions related to blockchains in complex Internet of Things(IoT)-based ecosystems.Such ecosystems are typically composed of IoT devices,edge devices,cloud computing software services,as well as people,who are decision makers in scenarios such as smart cities.Many decisions related to analytics can be based on data coming from IoT sensors,software services,and people.However,they are typically based on different levels of abstraction and granularity.This poses a number of challenges when multiple blockchains are used together with smart contracts.This work proposes to apply our concept of elasticity to smart contracts and thereby enabling analytics in and between multiple blockchains in the context of IoT.We propose a reference architecture for Elastic Smart Contracts and evaluate the approach in a smart city scenario,discussing the benefits in terms of performance and self-adaptability of our solution.展开更多
Due to the rigorous fiscal terms and huge potential risk of risk service contracts,optimizing oil production paths is one of the main challenges in designing oilfield development plans.In this paper,an oil production ...Due to the rigorous fiscal terms and huge potential risk of risk service contracts,optimizing oil production paths is one of the main challenges in designing oilfield development plans.In this paper,an oil production path optimization model is developed to maximize economic benefits within constraints of technology factors and oil contracts.This analysis describes the effects of risk service contract terms on parameters of inputs and outputs and quantifies the relationships between production and production time,revenues,investment and costs.An oil service development and production project is illustrated in which the optimal production path under its own geological conditions and contract terms is calculated.The influences of oil price,service fees per barrel and operating costs on the optimal production have been examined by sensitivity analysis.The results show that the oil price has the largest impact on the optimal production,which is negatively related to oil price and positively related to service fees per barrel and operating costs.展开更多
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,vulnerabi...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.展开更多
The emergence of smart contracts has increased the attention of industry and academia to blockchain technology,which is tamper-proofing,decentralized,autonomous,and enables decentralized applications to operate in unt...The emergence of smart contracts has increased the attention of industry and academia to blockchain technology,which is tamper-proofing,decentralized,autonomous,and enables decentralized applications to operate in untrustworthy environments.However,these features of this technology are also easily exploited by unscrupulous individuals,a typical example of which is the Ponzi scheme in Ethereum.The negative effect of unscrupulous individuals writing Ponzi scheme-type smart contracts in Ethereum and then using these contracts to scam large amounts of money has been significant.To solve this problem,we propose a detection model for detecting Ponzi schemes in smart contracts using bytecode.In this model,our innovation is shown in two aspects:We first propose to use two bytes as one characteristic,which can quickly transform the bytecode into a high-dimensional matrix,and this matrix contains all the implied characteristics in the bytecode.Then,We innovatively transformed the Ponzi schemes detection into an anomaly detection problem.Finally,an anomaly detection algorithm is used to identify Ponzi schemes in smart contracts.Experimental results show that the proposed detection model can greatly improve the accuracy of the detection of the Ponzi scheme contracts.Moreover,the F1-score of this model can reach 0.88,which is far better than those of other traditional detection models.展开更多
Forestry contracts of the Qing Dynasty in Jinping County, southwest China’s Guizhou Province, are a unique historical legacy of China. It came into being with the development of society and economy of Jinping. Resear...Forestry contracts of the Qing Dynasty in Jinping County, southwest China’s Guizhou Province, are a unique historical legacy of China. It came into being with the development of society and economy of Jinping. Research on these contracts is becoming widespread domestically and abroad as well. This paper is intended to make a review of the collection and research of forestry contracts in Jinping according to the chronological sequence.展开更多
This paper analyzes an electronic procurement （e-procurement） process between a manufacturer and N-supplier in the e-market. We proof that using the general contract based on auction theory, i. e. the wholesale pric...This paper analyzes an electronic procurement （e-procurement） process between a manufacturer and N-supplier in the e-market. We proof that using the general contract based on auction theory, i. e. the wholesale price contract, would not achieve the coordination of channel composed of the manufacturer and the winning supplier. The paper designs a contract mechanism, i.e. the side payment price-restricted contract based on auction theory, which not only ensures Pareto optimal solutions for both, but also coordinates the supply chain. A numerical experiment is provided to compare the performance of different auction mechanisms and to reinforce key managerial insights generated through analysis.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
Aiming at the incentive problems of venture capital syndication at the second and later stages, an game model is set up by principal agent and incentive theory, given that the lead venture capitalist has already some ...Aiming at the incentive problems of venture capital syndication at the second and later stages, an game model is set up by principal agent and incentive theory, given that the lead venture capitalist has already some knowledge of the project quality from his initial funding of the project. Under symmetric and asymmetric information, the model analyzes how the optimal syndication contracts induce venture capitalists to truthfully reveal their information to each other, and vary with the level of venture capitalists＇ expertise and information in evaluating projects.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
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.
基金Fund Project:NationalSocial Science Fund of China(NSSFC)Key Project 18AFX021:Research on Intellectual Property Legislation Issues in the Post-Civil Code Era。
文摘The Book on Contracts of the Civil Code does not recognize"intellectual property contracts"as nominate contracts.Owing to both substantive and structural shortcomings,the Chapter on Technology Contracts falls short of providing comprehensive regulation of transactions involving intellectual property,and its Article 876 linking clause has given rise to legal controversies over application by reference and priority of application.There is therefore an urgent need to recognize intellectual property contracts as a nominate category.The rules on such contracts that are dispersed across standalone intellectual property statutes,specialized regulations,adjudicated cases,and judicial interpretations have already produced decodification and should be integrated in the course of enacting the Intellectual Property Code,so as to achieve the recodification of contracts concerning intellectual property.Specifically,the Chapter on Contracts should consist of two parts,General Provisions and Nominate Contracts,to articulate the common features and specific rules of the various contract types while confirming the applicability of the General Provisions in the Book on Contracts.In this way,systemic disorder from mechanically adding nominate contracts to the Civil Code and unnecessary complexity from creating a separate sectoral contract code can both be avoided,and the status of the Book on Contracts as the basic law in the field of contract can be preserved.
文摘This article explores the characteristics of data resources from the perspective of production factors,analyzes the demand for trustworthy circulation technology,designs a fusion architecture and related solutions,including multi-party data intersection calculation,distributed machine learning,etc.It also compares performance differences,conducts formal verification,points out the value and limitations of architecture innovation,and looks forward to future opportunities.
基金supported by theHigher Education Research Project of Jilin Province:JGJX24C118the National Defense Basic Scientific Research Program of China(No.JCKY2023602C026).
文摘With the rapid proliferation of Internet ofThings(IoT)devices,ensuring their communication security has become increasingly important.Blockchain and smart contract technologies,with their decentralized nature,provide strong security guarantees for IoT.However,at the same time,smart contracts themselves face numerous security challenges,among which reentrancy vulnerabilities are particularly prominent.Existing detection tools for reentrancy vulnerabilities often suffer from high false positive and false negative rates due to their reliance on identifying patterns related to specific transfer functions.To address these limitations,this paper proposes a novel detection method that combines pattern matching with deep learning.Specifically,we carefully identify and define three common patterns of reentrancy vulnerabilities in smart contracts.Then,we extract key vulnerability features based on these patterns.Furthermore,we employ a Graph Attention Neural Network to extract graph embedding features from the contract graph,capturing the complex relationships between different components of the contract.Finally,we use an attention mechanism to fuse these two sets of feature information,enhancing the weights of effective information and suppressing irrelevant information,thereby significantly improving the accuracy and robustness of vulnerability detection.Experimental results demonstrate that our proposed method outperforms existing state-ofthe-art techniques,achieving a 3.88%improvement in accuracy compared to the latest vulnerability detection model AME(Attentive Multi-Encoder Network).This indicates that our method effectively reduces false positives and false negatives,significantly enhancing the security and reliability of smart contracts in the evolving IoT ecosystem.
文摘The challenge for supply chain management is to create appropriate supply chain contracts so as to optimize the system performance. To examine the role of asymmetric information in a two-echelon supply chain system and derive supply chain contracts to deal with existing asymmetric information, a two level supply chain model including one Supplier and one retailer under the demand of price elasticity is developed. By using the principalagent principle and the optimal control theory, three types of supply chain contract, i. e. , a wholesale pricing contract, a two-parameter linear and a two-parameter nonlinear contracts are obtained. In these contracts, the Supplier has asymmetric information about the retailer cost structure. Simulation results show that the two-parameter contracts are more effective strategies to achieve supply chain coordination.
文摘A majority of contracts will use many prepositions and prepositional phrases to reflect their preciseness which cause the treaty wording complicated and hard to understand. This paper tends to demonstrate the characteristics of the prepositions and prepositional phrases used in business English contracts and explore the translation strategies used in translating the features of the prepositions and the prepositional phrases in business English contracts. The findings of this paper can provide a reference for the majority of the trade workers, which can help them accurately and effectively draft or translate a contract and avoid unnecessary disputes.
文摘This paper tries to demonstrate that the principle of the risk allocation based on the balance is the most effective way to resolve the risk allocation problems of public-private partnership （PPP） contracts and presents suggestions how to carry out this principle. For PPP projects, it is necessary to set up a workable and commercially viable risk sharing mechanism to satisfy the different interests and the objectives of both the public sector and the private sector. An effective risk allocation mechanism is not only an important part in preparing project documents, but also an essential part in the success of PPP contracts. Risk allocation can be represented in a risk matrix. The more balanced the risk allocation is, the lower the risk degree of PPP contracts is. Therefore, the most effective risk allocation of PPP contracts is that the public sector and the private sector take part in risk management together in all the stages of the project and allocate the balanced risks. The outcomes of this paper can be used by both the public sector and the private sector to make a good choice of the PPP contract form.
文摘Production sharing contracts have been used in the development of China’s offshore petroleum resources since 1982, but the mechanism in which the fiscal terms impact project economics is complicated and not well understood. The purpose of this paper is to model China’s offshore production sharing contracts using a probabilistic approach. Cash flows and economic indicators are used for a typical offshore oilfield development, and meta-models are constructed to analyze the basic features of the fiscal system. Applications of the models in contract negotiation are discussed.
基金supported by the Science and Technology Project of Zhejiang Province(2009C11026,2009C35007)
文摘In supply chain management,an important research direction is to coordinate the supply chain through introducing flexible contracts.A supply chain contract is flexible if it can satisfy two conditions at the same time:the supply chain is coordinated,and the total profit of the supply chain can be arbitrarily divided between the supply chain members.This paper puts out two contracts,a flexible return contract and a flexible wholesale price discount contract.In contrast to many of literature,the supply chain contracts with an endogenous wholesale price is specifically considered,and a detailed sensitivity analysis of the contract parameters is given.The paper also discusses the application of the contract in vendor-managed inventory(VMI)mode.The results show that the supply chain's performance is improved after introducing above contracts.All the findings are illustrated by numerical examples.
基金provided through the U.S. Department of the Interior, Bureau of Ocean Energy Management
文摘The offshore pipeline network in the U.S. Gulf of Mexico is the largest and most transparent system in the world. A review of deepwater projects in the region provides insight into construction cost and installation methods and the evolution of contract strategies. Pipeline projects are identified as export systems, infield flowline systems, and combined export and infield systems, and three dozen deepwater pipeline installations from 1980–2014 are described based on Offshore Technology Conference(OTC) and Society of Petroleum Engineers(SPE) industry publications and press release data. Export lines and infield flowlines are equally represented and many projects used a combination of J-lay, S-lay and reel methods with rigid steel, flexible line, and pipe-in-pipe systems. The average 2014 inflation-adjusted cost for pipeline projects based on OTC/SPE publications was $2.76 million/mi and ranged from $520 000/mi to $12.94 million/mi. High cost pipelines tend to be short segments or specialized pipeline. Excluding the two cost endpoints, the majority of projects ranged from $1 to $6 million/mi. The average inflation-adjusted cost to install deepwater pipelines in the U.S. Gulf of Mexico based on available public data is estimated at $3.1 million/mi.
基金This work was partially supported by FEDER/Ministerio de Ciencia e Innovación-Agencia Estatal de Investigación under project HORATIO(RTI2018-101204-B-C21)by Junta de Andalucía under projects APOLO(US-1264651)and EKIPMENT-PLUS(P18-FR-2895)by the TU Wien Research Cluster Smart CT.
文摘In this paper,we deal with questions related to blockchains in complex Internet of Things(IoT)-based ecosystems.Such ecosystems are typically composed of IoT devices,edge devices,cloud computing software services,as well as people,who are decision makers in scenarios such as smart cities.Many decisions related to analytics can be based on data coming from IoT sensors,software services,and people.However,they are typically based on different levels of abstraction and granularity.This poses a number of challenges when multiple blockchains are used together with smart contracts.This work proposes to apply our concept of elasticity to smart contracts and thereby enabling analytics in and between multiple blockchains in the context of IoT.We propose a reference architecture for Elastic Smart Contracts and evaluate the approach in a smart city scenario,discussing the benefits in terms of performance and self-adaptability of our solution.
基金Funding for this work was provided by the Major Project from the National Social Science Foundation of China through research on replacement strategies for overseas oil and gas resources based on the perspective of China’s petroleum security under the project number 11&ZD164
文摘Due to the rigorous fiscal terms and huge potential risk of risk service contracts,optimizing oil production paths is one of the main challenges in designing oilfield development plans.In this paper,an oil production path optimization model is developed to maximize economic benefits within constraints of technology factors and oil contracts.This analysis describes the effects of risk service contract terms on parameters of inputs and outputs and quantifies the relationships between production and production time,revenues,investment and costs.An oil service development and production project is illustrated in which the optimal production path under its own geological conditions and contract terms is calculated.The influences of oil price,service fees per barrel and operating costs on the optimal production have been examined by sensitivity analysis.The results show that the oil price has the largest impact on the optimal production,which is negatively related to oil price and positively related to service fees per barrel and operating costs.
基金funded by the Major PublicWelfare Special Fund of Henan Province(No.201300210200)the Major Science and Technology Research Special Fund of Henan Province(No.221100210400).
文摘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.
基金This work was supported by the Scientific and Technological Project of Henan Province(Grant No.202102310340)Foundation of University Young Key Teacher of Henan Province(Grant Nos.2019GGJS040,2020GGJS027)+1 种基金Key Scientific Research Projects of Colleges and Universities in Henan Province(Grant No.21A110005)National Natual Science Foundation of China(61701170).
文摘The emergence of smart contracts has increased the attention of industry and academia to blockchain technology,which is tamper-proofing,decentralized,autonomous,and enables decentralized applications to operate in untrustworthy environments.However,these features of this technology are also easily exploited by unscrupulous individuals,a typical example of which is the Ponzi scheme in Ethereum.The negative effect of unscrupulous individuals writing Ponzi scheme-type smart contracts in Ethereum and then using these contracts to scam large amounts of money has been significant.To solve this problem,we propose a detection model for detecting Ponzi schemes in smart contracts using bytecode.In this model,our innovation is shown in two aspects:We first propose to use two bytes as one characteristic,which can quickly transform the bytecode into a high-dimensional matrix,and this matrix contains all the implied characteristics in the bytecode.Then,We innovatively transformed the Ponzi schemes detection into an anomaly detection problem.Finally,an anomaly detection algorithm is used to identify Ponzi schemes in smart contracts.Experimental results show that the proposed detection model can greatly improve the accuracy of the detection of the Ponzi scheme contracts.Moreover,the F1-score of this model can reach 0.88,which is far better than those of other traditional detection models.
文摘Forestry contracts of the Qing Dynasty in Jinping County, southwest China’s Guizhou Province, are a unique historical legacy of China. It came into being with the development of society and economy of Jinping. Research on these contracts is becoming widespread domestically and abroad as well. This paper is intended to make a review of the collection and research of forestry contracts in Jinping according to the chronological sequence.
基金Supported by the National Natural ScienceFoundation of China (70471034)
文摘This paper analyzes an electronic procurement （e-procurement） process between a manufacturer and N-supplier in the e-market. We proof that using the general contract based on auction theory, i. e. the wholesale price contract, would not achieve the coordination of channel composed of the manufacturer and the winning supplier. The paper designs a contract mechanism, i.e. the side payment price-restricted contract based on auction theory, which not only ensures Pareto optimal solutions for both, but also coordinates the supply chain. A numerical experiment is provided to compare the performance of different auction mechanisms and to reinforce key managerial insights generated through analysis.
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Aiming at the incentive problems of venture capital syndication at the second and later stages, an game model is set up by principal agent and incentive theory, given that the lead venture capitalist has already some knowledge of the project quality from his initial funding of the project. Under symmetric and asymmetric information, the model analyzes how the optimal syndication contracts induce venture capitalists to truthfully reveal their information to each other, and vary with the level of venture capitalists＇ expertise and information in evaluating projects.
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.
