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 satis...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.展开更多
To improve the performance of the supply chain with one supplier and multiple retailers under deterministic price-sensitive customer demand, an optimal strategy is proposed based on knowledge discovery. First the dece...To improve the performance of the supply chain with one supplier and multiple retailers under deterministic price-sensitive customer demand, an optimal strategy is proposed based on knowledge discovery. First the decentralized system in which the supplier and the retailers are independent, profit-maximizing participants with the supplier acting as a Stackelberg game leader is studied. Numerical examples illustrate the importance of the coordination. The conventional quantity discount mechanism needs to be modified to coordinate the supply chain, so a revenue-sharing contract is proposed to coordinate such supply chain. Lastly, a special decision under certain demand rates is studied. The pricing and replenishment policies can be decided sequentially, which yields much less loss comparing with optimal decision when the demand rates are sufficiently large.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
Many reviews and evaluations of contract farming and its importance for small-scale farmers in the developing nations have been conducted. While some scholars opined that contractual terms were unfavourable to farmers...Many reviews and evaluations of contract farming and its importance for small-scale farmers in the developing nations have been conducted. While some scholars opined that contractual terms were unfavourable to farmers, others considerd them as being beneficial to them. These contrasting views were not likely to discourage it since it provided encouragement for farmers＇ involvement in markets. It was therefore worthwhile to investigate previous experiences with the aim of improving on it. This study investigated contract farming entered into by farmers in Delta State of Nigeria and livestock feed companies with the objective of seeking ways to make such contractual agreements beneficial to small-scale farmers. The study utilized convergence of science approach. The study unveiled the constraints experienced by farmers and they included technical and institutional challenges. The technical problem was the planting date, while the institutional problem was the contractual arrangements. It was recommended that all the stakeholders in the contract should converge and negotiate technological adoptions of the improved maize varieties; contract needed to be clearly def＇med and risks and uncertainties should be parts of the contract; scientific investigations should be carded out to determine the best planting date; and there was need for legislation to particularly protect farmers in contract farming.展开更多
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 ...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.展开更多
Labor Contract Law receives mixed evaluations since its implementation.The call for the amendment is hot and even some scholars regard it as the"tiger in the road"which hinders the economic development. The ...Labor Contract Law receives mixed evaluations since its implementation.The call for the amendment is hot and even some scholars regard it as the"tiger in the road"which hinders the economic development. The Central Committee of the Communist Party of China pays high attention to the construction of harmonious labor relation and the amendment has been a top priority. Labor Contract Law leads to two"deadlocks"of which the entrepreneurs are afraid. The first one is that the non-fixed term labor contract cannot be cancelled and the second one is that they must pay the economic compensation at the expiration of contract. These two rules hinder the employment enthusiasm of entrepreneurs. The current laws have excessive expectation for the non-fixed term labor contract and too strict regulations; as for the economic compensation at the expiration of contract, it increases the enterprise cost. The amendment of these two articles will benefit the recovery of Chinese economy and make the labor relation more harmonious.展开更多
Objective Patients with repaired tetralogy of Fallot(rTOF)account for the majority of cases with late onset right ventricle(RV)failure.The current surgical approach,including pulmonary valve replacement/insertion(PVR)...Objective Patients with repaired tetralogy of Fallot(rTOF)account for the majority of cases with late onset right ventricle(RV)failure.The current surgical approach,including pulmonary valve replacement/insertion(PVR),has yielded mixed results with some patients recover RV function and some do not.An innovative surgical approach was proposed to help ventricle to contract and improve RV function qualified by ejection fraction with one or more active contracting bands.Computational biomechanical modelling is a widely used method in cardiovascular study for investigation of mechanisms governing disease development,quantitative diagnostic and treatment strategies and improving surgical designs for better outcome.Muscle active contraction caused by zero-load sarcomere shortening leads to change of zero-load configurations.In lieu of experimenting using real surgery on animal or human,computational simulations(virtual surgery)were performed to test different band combination and insertion options to identify optimal surgery design and band insertion plan.Methods Cardiac magnetic resonance(CMR)data were obtained from one rTOF patient(sex:male,age:22.5 y)before pulmonary valve replacement surgery.The patient was suffering from RV dilation and dysfunction with RV end-systole volume 254.49ml and end-diastole volume 406.91 mL.A total of 15 computational RV/LV/Patch/Band combination models based on(CMR)imaging were constructed to investigate the influence of different band insertion surgery plans.These models included 5 different band insertion models combined and 3 different band contraction ratio(10%,15%and 20%band zero-stress length reduction).These models included 5 different band insertion models:Model 1 with one band at anterior to the middle of papillary muscle;Model 2 with one band at posterior to the middle of papillary muscle;Model 3 with 2 bands which are the ones from Models 1&2 combined;Model 4 with a band at the base of the papillary muscle;Model 5 with 3 bands which is a combination of Models 3&4.A pre-shrink process was performed on in-vivo begin-filling and end-systole MRI data to obtain diastole and systole zero4oad ventricle geometries.An extra 5%-8%shrinkage was applied to obtain corresponding systole zero-load geometry reflecting myocardium sarcomere shortening.The zero-load band length in systole was 10%,15%and 20%shorter than that in diastole according to their corresponding contraction ratio.The nonlinear Mooney-Rivlin model was used to describe the ventricle material properties with their material parameter values adjusted to match measured data with CMR.The band material properties were in the same scale with healthy right ventricle.The RV/LV/Band model construction and solution procedures were the same as described.Results Model 5 with band contraction ratio of 20%has the ability to improve RV ejection fraction to 41.07%,which represented a 3.61%absolute improvement,or 9.6%relative improvement using pre-PVR ejection fraction as the baseline number.The ejection fractions for Models 1-4 with band contraction ratio of 20%were 39.28%,39.47%,38.87%and 40.34%respectively.Compared to models with band contraction ratio15%and 20%,models with band contraction ratio 10%has the least ability on RV ejection fraction improvement with ejection fraction 38.28%,38.00%,38.81%,38.50%and 39.36%corresponding to Models 1-5.Conclusions This pilot work demonstrated that the band insertion surgery may have great potential to improve post-PVR RV cardiac function for patients with repaired TOF.More band contraction ratio and inserted band number may lead to better post-surgery outcome.Further investigations using in-vitro animal experiments and final patient studies are warranted.展开更多
When an expanded-base pile is installed into ground, the cavity expansion associated with penetration of the enlarged pile base is followed by cavity contraction along the smaller-diameter pile shaft. In order to acco...When an expanded-base pile is installed into ground, the cavity expansion associated with penetration of the enlarged pile base is followed by cavity contraction along the smaller-diameter pile shaft. In order to account for the influence of cavity contraction on the change of bearing capacity of expanded-base pile, a theoretical calculation methodology, predicting the setup of expanded-base pile, was established by employing the cavity contraction theory to estimate the shaft resistance of expanded-base pile, and horizontal consolidation theory to predict the dissipation of excess pore pressure. Finally, the numerical solutions for the setup of expanded-base pile were obtained. The parametric study about the influence of cavity contraction on setup of expanded-base pile was carried out, while a field test was introduced. The parametric study shows that the decrements in radial pressure and the maximum pore water pressure after considering cavity contraction are increased as the expanded ratio(base diameter/shaft diameter) and rigidity index of soil are raised. The comparison between calculated and measured values shows that the calculated results of ultimate bearing capacity for expanded-base pile considering cavity contraction agree well with the measured values; however, the computations ignoring cavity contraction are 2.5-3.0 times the measured values.展开更多
The interpretation of contract has attracted much attention in the practice of contract law and the basic problems to be solved are what the parties agree on and how to set up the rules of adjudication.The present dom...The interpretation of contract has attracted much attention in the practice of contract law and the basic problems to be solved are what the parties agree on and how to set up the rules of adjudication.The present domestic studies are not conducive to contract practices because they either unnecessarily elevate scientific problems to the speculative realm of fantasy,or make the problems become more unreal and abstract.The two traditional theories of contract interpretation do not conflict in values in terms of the autonomy of the will and trust protection.However,in today' s society where cultural pluralism and legal value pluralism exist,because of different contract practices,differentiation and individualization of contract interpretation will become the basic patterns.Therefore,it is impossible and unnecessary to construct a unitary model,but it is of great significance to introduce the dogmatics-oriented contract interpretation.展开更多
Sharecropping has been an age long practice from ancient times. Some scholars saw the practice as being exploitative of the tenants, yet it is still being practiced. The reasons behind it continual practice need to be...Sharecropping has been an age long practice from ancient times. Some scholars saw the practice as being exploitative of the tenants, yet it is still being practiced. The reasons behind it continual practice need to be unveiled. This study was therefore conducted to examine the sharecropping contract experience in Delta State, Nigeria. The landlords decided to practice sharecropping as a result of emigration of their household members, farm size and cost of labours, some of them gave age and their primary occupation as factors for their decisions to opt for sharecropping arrangement. The yields were shared on the basis of 60% for the landlord to 40% for the tenant. The landlords provided all the equipment and inputs, while the tenant＇s carried out all the farm operations. They faced the constraints of stress, but were able to cope with them, because of hospitals and health centres nearby. The result of the test of hypothesis confirmed the reasons given for deciding on sharecropping arrangement. It was concluded that sharecropping was not exploitative. It was recommended that the practice of sharecropping should be encouraged and not diversified into other sources of livelihood should do so.展开更多
The study was to investigate the effect of reducing central sympathetic nervous tone with clonidine on cardiomyocyte contraction,and further to analyze the influence of reducing the central sympathetic nervous tone on...The study was to investigate the effect of reducing central sympathetic nervous tone with clonidine on cardiomyocyte contraction,and further to analyze the influence of reducing the central sympathetic nervous tone on response of β1 and β2-AR in aged ventricular myocytes.Sprague-Dawley rats were randomly divided into three groups:adult group,aged group and aged group with clonidine.展开更多
针对现有用户协作算法存在共谋攻击、背景知识攻击以及用户协作意愿等问题,基于可验证秘密共享与智能合约提出了一种用户协作隐私保护算法(privacy protection algorithm based on verifiable secret sharing and smart contracts,VSS-S...针对现有用户协作算法存在共谋攻击、背景知识攻击以及用户协作意愿等问题,基于可验证秘密共享与智能合约提出了一种用户协作隐私保护算法(privacy protection algorithm based on verifiable secret sharing and smart contracts,VSS-SCPPA)。该算法首先利用可验证秘密共享算法对用户查询信息进行加密和分裂,并提供系数承诺以验证子秘密数据的完整性。其次,结合智能合约与差分隐私技术设计了一种用户选择算法,构建匿名集。对该算法在抵御串通攻击方面的有效性进行了分析。通过在Geolife与BerlinMOD数据集上的实验,结果显示VSS-SCPPA的隐私保护性更高。与Tr-privacy、Ik-anonymity和GCS相比,VSS-SCPPA的效率分别提高了约86.34%、99.27%和99.19%。VSS-SCPPA在提高隐私保护性的同时显著提升了算法效率,证明了其在用户协作隐私保护中的有效性。展开更多
基金supported by the National Natural Science Foundation of China(71671035)。
文摘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.
基金the National Natural Science Foundation of China (70471034)the Talent Foundation of Nanjing University of Aeronautics and Astronautics (s0670-082).
文摘To improve the performance of the supply chain with one supplier and multiple retailers under deterministic price-sensitive customer demand, an optimal strategy is proposed based on knowledge discovery. First the decentralized system in which the supplier and the retailers are independent, profit-maximizing participants with the supplier acting as a Stackelberg game leader is studied. Numerical examples illustrate the importance of the coordination. The conventional quantity discount mechanism needs to be modified to coordinate the supply chain, so a revenue-sharing contract is proposed to coordinate such supply chain. Lastly, a special decision under certain demand rates is studied. The pricing and replenishment policies can be decided sequentially, which yields much less loss comparing with optimal decision when the demand rates are sufficiently large.
基金supported by the Science and Technology Project of Zhejiang Province (2009C110262009C35007)
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.
文摘Many reviews and evaluations of contract farming and its importance for small-scale farmers in the developing nations have been conducted. While some scholars opined that contractual terms were unfavourable to farmers, others considerd them as being beneficial to them. These contrasting views were not likely to discourage it since it provided encouragement for farmers＇ involvement in markets. It was therefore worthwhile to investigate previous experiences with the aim of improving on it. This study investigated contract farming entered into by farmers in Delta State of Nigeria and livestock feed companies with the objective of seeking ways to make such contractual agreements beneficial to small-scale farmers. The study utilized convergence of science approach. The study unveiled the constraints experienced by farmers and they included technical and institutional challenges. The technical problem was the planting date, while the institutional problem was the contractual arrangements. It was recommended that all the stakeholders in the contract should converge and negotiate technological adoptions of the improved maize varieties; contract needed to be clearly def＇med and risks and uncertainties should be parts of the contract; scientific investigations should be carded out to determine the best planting date; and there was need for legislation to particularly protect farmers in contract farming.
基金National Natural Science Foundation of China(62173066)Open Project of Sichuan Provincial Key Laboratory of Intelligent Terminal Co-built by Province and City(SCITLAB-1014)。
文摘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.
基金Projects of the National Social Science Foundation of China“research on the response of the labor standard under new normal for the group hostility between capital and labor”(15BGL184)
文摘Labor Contract Law receives mixed evaluations since its implementation.The call for the amendment is hot and even some scholars regard it as the"tiger in the road"which hinders the economic development. The Central Committee of the Communist Party of China pays high attention to the construction of harmonious labor relation and the amendment has been a top priority. Labor Contract Law leads to two"deadlocks"of which the entrepreneurs are afraid. The first one is that the non-fixed term labor contract cannot be cancelled and the second one is that they must pay the economic compensation at the expiration of contract. These two rules hinder the employment enthusiasm of entrepreneurs. The current laws have excessive expectation for the non-fixed term labor contract and too strict regulations; as for the economic compensation at the expiration of contract, it increases the enterprise cost. The amendment of these two articles will benefit the recovery of Chinese economy and make the labor relation more harmonious.
基金supported in part by National Sciences Foundation of China grants ( 11672001, 81571691,81771844)
文摘Objective Patients with repaired tetralogy of Fallot(rTOF)account for the majority of cases with late onset right ventricle(RV)failure.The current surgical approach,including pulmonary valve replacement/insertion(PVR),has yielded mixed results with some patients recover RV function and some do not.An innovative surgical approach was proposed to help ventricle to contract and improve RV function qualified by ejection fraction with one or more active contracting bands.Computational biomechanical modelling is a widely used method in cardiovascular study for investigation of mechanisms governing disease development,quantitative diagnostic and treatment strategies and improving surgical designs for better outcome.Muscle active contraction caused by zero-load sarcomere shortening leads to change of zero-load configurations.In lieu of experimenting using real surgery on animal or human,computational simulations(virtual surgery)were performed to test different band combination and insertion options to identify optimal surgery design and band insertion plan.Methods Cardiac magnetic resonance(CMR)data were obtained from one rTOF patient(sex:male,age:22.5 y)before pulmonary valve replacement surgery.The patient was suffering from RV dilation and dysfunction with RV end-systole volume 254.49ml and end-diastole volume 406.91 mL.A total of 15 computational RV/LV/Patch/Band combination models based on(CMR)imaging were constructed to investigate the influence of different band insertion surgery plans.These models included 5 different band insertion models combined and 3 different band contraction ratio(10%,15%and 20%band zero-stress length reduction).These models included 5 different band insertion models:Model 1 with one band at anterior to the middle of papillary muscle;Model 2 with one band at posterior to the middle of papillary muscle;Model 3 with 2 bands which are the ones from Models 1&2 combined;Model 4 with a band at the base of the papillary muscle;Model 5 with 3 bands which is a combination of Models 3&4.A pre-shrink process was performed on in-vivo begin-filling and end-systole MRI data to obtain diastole and systole zero4oad ventricle geometries.An extra 5%-8%shrinkage was applied to obtain corresponding systole zero-load geometry reflecting myocardium sarcomere shortening.The zero-load band length in systole was 10%,15%and 20%shorter than that in diastole according to their corresponding contraction ratio.The nonlinear Mooney-Rivlin model was used to describe the ventricle material properties with their material parameter values adjusted to match measured data with CMR.The band material properties were in the same scale with healthy right ventricle.The RV/LV/Band model construction and solution procedures were the same as described.Results Model 5 with band contraction ratio of 20%has the ability to improve RV ejection fraction to 41.07%,which represented a 3.61%absolute improvement,or 9.6%relative improvement using pre-PVR ejection fraction as the baseline number.The ejection fractions for Models 1-4 with band contraction ratio of 20%were 39.28%,39.47%,38.87%and 40.34%respectively.Compared to models with band contraction ratio15%and 20%,models with band contraction ratio 10%has the least ability on RV ejection fraction improvement with ejection fraction 38.28%,38.00%,38.81%,38.50%and 39.36%corresponding to Models 1-5.Conclusions This pilot work demonstrated that the band insertion surgery may have great potential to improve post-PVR RV cardiac function for patients with repaired TOF.More band contraction ratio and inserted band number may lead to better post-surgery outcome.Further investigations using in-vitro animal experiments and final patient studies are warranted.
基金Project(LQ15E080002)supported by Zhejiang Provincial Natural Science Foundation of ChinaProjects(5150828251478228)supported by the National Natural Science Foundation of China
文摘When an expanded-base pile is installed into ground, the cavity expansion associated with penetration of the enlarged pile base is followed by cavity contraction along the smaller-diameter pile shaft. In order to account for the influence of cavity contraction on the change of bearing capacity of expanded-base pile, a theoretical calculation methodology, predicting the setup of expanded-base pile, was established by employing the cavity contraction theory to estimate the shaft resistance of expanded-base pile, and horizontal consolidation theory to predict the dissipation of excess pore pressure. Finally, the numerical solutions for the setup of expanded-base pile were obtained. The parametric study about the influence of cavity contraction on setup of expanded-base pile was carried out, while a field test was introduced. The parametric study shows that the decrements in radial pressure and the maximum pore water pressure after considering cavity contraction are increased as the expanded ratio(base diameter/shaft diameter) and rigidity index of soil are raised. The comparison between calculated and measured values shows that the calculated results of ultimate bearing capacity for expanded-base pile considering cavity contraction agree well with the measured values; however, the computations ignoring cavity contraction are 2.5-3.0 times the measured values.
文摘The interpretation of contract has attracted much attention in the practice of contract law and the basic problems to be solved are what the parties agree on and how to set up the rules of adjudication.The present domestic studies are not conducive to contract practices because they either unnecessarily elevate scientific problems to the speculative realm of fantasy,or make the problems become more unreal and abstract.The two traditional theories of contract interpretation do not conflict in values in terms of the autonomy of the will and trust protection.However,in today' s society where cultural pluralism and legal value pluralism exist,because of different contract practices,differentiation and individualization of contract interpretation will become the basic patterns.Therefore,it is impossible and unnecessary to construct a unitary model,but it is of great significance to introduce the dogmatics-oriented contract interpretation.
文摘Sharecropping has been an age long practice from ancient times. Some scholars saw the practice as being exploitative of the tenants, yet it is still being practiced. The reasons behind it continual practice need to be unveiled. This study was therefore conducted to examine the sharecropping contract experience in Delta State, Nigeria. The landlords decided to practice sharecropping as a result of emigration of their household members, farm size and cost of labours, some of them gave age and their primary occupation as factors for their decisions to opt for sharecropping arrangement. The yields were shared on the basis of 60% for the landlord to 40% for the tenant. The landlords provided all the equipment and inputs, while the tenant＇s carried out all the farm operations. They faced the constraints of stress, but were able to cope with them, because of hospitals and health centres nearby. The result of the test of hypothesis confirmed the reasons given for deciding on sharecropping arrangement. It was concluded that sharecropping was not exploitative. It was recommended that the practice of sharecropping should be encouraged and not diversified into other sources of livelihood should do so.
文摘The study was to investigate the effect of reducing central sympathetic nervous tone with clonidine on cardiomyocyte contraction,and further to analyze the influence of reducing the central sympathetic nervous tone on response of β1 and β2-AR in aged ventricular myocytes.Sprague-Dawley rats were randomly divided into three groups:adult group,aged group and aged group with clonidine.
文摘针对现有用户协作算法存在共谋攻击、背景知识攻击以及用户协作意愿等问题,基于可验证秘密共享与智能合约提出了一种用户协作隐私保护算法(privacy protection algorithm based on verifiable secret sharing and smart contracts,VSS-SCPPA)。该算法首先利用可验证秘密共享算法对用户查询信息进行加密和分裂,并提供系数承诺以验证子秘密数据的完整性。其次,结合智能合约与差分隐私技术设计了一种用户选择算法,构建匿名集。对该算法在抵御串通攻击方面的有效性进行了分析。通过在Geolife与BerlinMOD数据集上的实验,结果显示VSS-SCPPA的隐私保护性更高。与Tr-privacy、Ik-anonymity和GCS相比,VSS-SCPPA的效率分别提高了约86.34%、99.27%和99.19%。VSS-SCPPA在提高隐私保护性的同时显著提升了算法效率,证明了其在用户协作隐私保护中的有效性。
