The Cloud is increasingly being used to store and process big data for its tenants and classical security mechanisms using encryption are neither sufficiently efficient nor suited to the task of protecting big data in...The Cloud is increasingly being used to store and process big data for its tenants and classical security mechanisms using encryption are neither sufficiently efficient nor suited to the task of protecting big data in the Cloud.In this paper,we present an alternative approach which divides big data into sequenced parts and stores them among multiple Cloud storage service providers.Instead of protecting the big data itself,the proposed scheme protects the mapping of the various data elements to each provider using a trapdoor function.Analysis,comparison and simulation prove that the proposed scheme is efficient and secure for the big data of Cloud tenants.展开更多
Aiming atthe pricing of primary agricultural products for the large-scale suppliers and the wholesalers in agri-supply chain management, an approach for the large-scale supplier pricing is presented based on the thres...Aiming atthe pricing of primary agricultural products for the large-scale suppliers and the wholesalers in agri-supply chain management, an approach for the large-scale supplier pricing is presented based on the threshold cointegration method of wholesale prices online including the GBand-TAR modified Band-TAR model. Our empirical work shows that it is more appropriate for a large-scale supplier pricing with his wholesalers based on the threshold cointegration method than the conventional linear cointegration method in spatially separate markets in an agri-supply chain of soybean in China in short time. Firstly, the three pairs of prices in spatially separate markets are of long-run equilibrium and threshold cointegration. The forecast wst shows that the threshold cointegration approach is superior to the conventional linear cointegration approach in short time. Secondly, there are two thresholds of GBand-TAR in which the threshold parameters represent relative transaction costs. Larger thresholds or wider neutral band corresponds to the greater distance between markets. Thirdly, the estimation of M-TAR shows that the large-scale supplier is more sensitive to increase of wholesaler prices than decrease of wholesaler prices. The supplier can price on the forecast of market price by the threshold ECM including the GBand-TAR if the equilibrium error of threshold lag is not in the interval of thresholds in which there is not profitable trading opportunities for the supplier.展开更多
IPv6 has been an inevitable trend with the depletion of the global IPv4 address space. However, new IPv6 users still need public IPv4 addresses to access global IPv4 users/resources, making it important for providers ...IPv6 has been an inevitable trend with the depletion of the global IPv4 address space. However, new IPv6 users still need public IPv4 addresses to access global IPv4 users/resources, making it important for providers to share scarce global IPv4 addresses effectively. There are two categories of solutions to the problem, carrier-grade NAT （CGN） and ＇A＋P＇ （each customer shaving the same IPv4 address is assigned an excluded port range）. However, both of them have limitations. Specifically, CGN solutions are not scalable and can bring much complexity in managing customers in large-scale deployments, while A＋P solutions are not flexible enough to meet dynamic port requirements. In this paper, we propose a hybrid mechanism to improve current solutions and have deployed it in the Tsinghua University Campus Network. The real traffic data shows that our mechanism can utilize limited IPv4 addresses efficiently without degrading the performance of applications on end hosts. Based on the enhanced mechanism, we propose a method to help service providers make address plans based on their own traffic patterns and actual requirements.展开更多
This paper studies the consignment contract with revenue sharing where the retailer offers two revenue share schemes between himself and his supplier from the viewpoint of inventory ownership: One is that the retailer...This paper studies the consignment contract with revenue sharing where the retailer offers two revenue share schemes between himself and his supplier from the viewpoint of inventory ownership: One is that the retailer takes charge of the unsold items,the other one is that the retailer returns the unsold items to the supplier at the end of the selling period,and the supplier disposes those overstockings.In each contract,the retailer deducts a percentage from the selling price for each sold item and transfers the balance to the supplier.The supplier solves a two-stage problem:She first chooses contract,then decides retail price and delivery quantity according to the terms of the contract chosen.With an iso-price-elastic demand model,the authors derive the retailer and suppliers’ optimal decisions for both schemes.In addition,the authors characterize how they are affected by disposing cost.The authors compare the decisions between the two schemes for disposing cost turn out to be holding cost or salvage value,respectively.The authors use numerical examples to show the supplier’s first-stage optimal decision depends critically on demand price elasticity,the disposing cost and the retailer’s share for channel cost.展开更多
This paper considers a buyer＇s procuring strategy where the buyer purchases products from a supplier in order to minimize his total cost. Assume that the customer arrivals follow a Poisson process, a base-stock polic...This paper considers a buyer＇s procuring strategy where the buyer purchases products from a supplier in order to minimize his total cost. Assume that the customer arrivals follow a Poisson process, a base-stock policy is implemented by the buyer, and the supplier will afford partial operating cost incurred by the buyer; The cost shared by the buyer includes procuring cost and some operating cost; The supplier does not hold the inventory and her production time is exponentially distributed. The objective of the supplier is to maximize her profit. The buyer designs a contract to minimize his total expected cost. Two different cases are considered： One potential supplier and many competing suppliers. The optimal control approaches are used to design the buyer＇s optimal mechanism and some simple procurement mechanisms are presented.展开更多
基金supported in part by the National Nature Science Foundation of China under Grant No.61402413 and 61340058 the "Six Kinds Peak Talents Plan" project of Jiangsu Province under Grant No.ll-JY-009+2 种基金the Nature Science Foundation of Zhejiang Province under Grant No.LY14F020019, Z14F020006 and Y1101183the China Postdoctoral Science Foundation funded project under Grant No.2012M511732Jiangsu Province Postdoctoral Science Foundation funded project Grant No.1102014C
文摘The Cloud is increasingly being used to store and process big data for its tenants and classical security mechanisms using encryption are neither sufficiently efficient nor suited to the task of protecting big data in the Cloud.In this paper,we present an alternative approach which divides big data into sequenced parts and stores them among multiple Cloud storage service providers.Instead of protecting the big data itself,the proposed scheme protects the mapping of the various data elements to each provider using a trapdoor function.Analysis,comparison and simulation prove that the proposed scheme is efficient and secure for the big data of Cloud tenants.
基金the Social Science Fund Program of Heilongjiang Province in China(Grant No.03B028)
文摘Aiming atthe pricing of primary agricultural products for the large-scale suppliers and the wholesalers in agri-supply chain management, an approach for the large-scale supplier pricing is presented based on the threshold cointegration method of wholesale prices online including the GBand-TAR modified Band-TAR model. Our empirical work shows that it is more appropriate for a large-scale supplier pricing with his wholesalers based on the threshold cointegration method than the conventional linear cointegration method in spatially separate markets in an agri-supply chain of soybean in China in short time. Firstly, the three pairs of prices in spatially separate markets are of long-run equilibrium and threshold cointegration. The forecast wst shows that the threshold cointegration approach is superior to the conventional linear cointegration approach in short time. Secondly, there are two thresholds of GBand-TAR in which the threshold parameters represent relative transaction costs. Larger thresholds or wider neutral band corresponds to the greater distance between markets. Thirdly, the estimation of M-TAR shows that the large-scale supplier is more sensitive to increase of wholesaler prices than decrease of wholesaler prices. The supplier can price on the forecast of market price by the threshold ECM including the GBand-TAR if the equilibrium error of threshold lag is not in the interval of thresholds in which there is not profitable trading opportunities for the supplier.
文摘IPv6 has been an inevitable trend with the depletion of the global IPv4 address space. However, new IPv6 users still need public IPv4 addresses to access global IPv4 users/resources, making it important for providers to share scarce global IPv4 addresses effectively. There are two categories of solutions to the problem, carrier-grade NAT （CGN） and ＇A＋P＇ （each customer shaving the same IPv4 address is assigned an excluded port range）. However, both of them have limitations. Specifically, CGN solutions are not scalable and can bring much complexity in managing customers in large-scale deployments, while A＋P solutions are not flexible enough to meet dynamic port requirements. In this paper, we propose a hybrid mechanism to improve current solutions and have deployed it in the Tsinghua University Campus Network. The real traffic data shows that our mechanism can utilize limited IPv4 addresses efficiently without degrading the performance of applications on end hosts. Based on the enhanced mechanism, we propose a method to help service providers make address plans based on their own traffic patterns and actual requirements.
基金supported by the National Natural Science Foundation of China under Grant Nos.70901029, 71171088,71131004 and 71002077the Fundamental Research Funds for the Universities under Grant No. 65010771
文摘This paper studies the consignment contract with revenue sharing where the retailer offers two revenue share schemes between himself and his supplier from the viewpoint of inventory ownership: One is that the retailer takes charge of the unsold items,the other one is that the retailer returns the unsold items to the supplier at the end of the selling period,and the supplier disposes those overstockings.In each contract,the retailer deducts a percentage from the selling price for each sold item and transfers the balance to the supplier.The supplier solves a two-stage problem:She first chooses contract,then decides retail price and delivery quantity according to the terms of the contract chosen.With an iso-price-elastic demand model,the authors derive the retailer and suppliers’ optimal decisions for both schemes.In addition,the authors characterize how they are affected by disposing cost.The authors compare the decisions between the two schemes for disposing cost turn out to be holding cost or salvage value,respectively.The authors use numerical examples to show the supplier’s first-stage optimal decision depends critically on demand price elasticity,the disposing cost and the retailer’s share for channel cost.
文摘This paper considers a buyer＇s procuring strategy where the buyer purchases products from a supplier in order to minimize his total cost. Assume that the customer arrivals follow a Poisson process, a base-stock policy is implemented by the buyer, and the supplier will afford partial operating cost incurred by the buyer; The cost shared by the buyer includes procuring cost and some operating cost; The supplier does not hold the inventory and her production time is exponentially distributed. The objective of the supplier is to maximize her profit. The buyer designs a contract to minimize his total expected cost. Two different cases are considered： One potential supplier and many competing suppliers. The optimal control approaches are used to design the buyer＇s optimal mechanism and some simple procurement mechanisms are presented.
