7283306
A Fair Item-Item Exchange Protocol Satisfying Newly Introduced Requirements
Many protocols are designed to guarantee fairness in electronic exchange that is widely used in e-commerce and e-government systems. In spite of the cryptographic view, we tend to view the fairness problem in a more complete vision. First we present a renewed set of requirement definitions for fair protocols. Second we study the encrypted item validation problem and present a simple and effective solution. With these preliminary discussions, we present our new item-item exchange protocol that is the first one to satisfy those newly introduced requirements
15968114
An Efficient Explicit-time Description Method for Timed Model Checking
Timed modelchecking,the methodtoformallyverifyreal-timesystems, is attractingincreasingatten-tion from both the model checking community and the real-time community. Explicit-time descrip-tion methods verify real-time systems using general model constructs found in standard un-timedmodel checkers. Lamport proposed an explicit-time description method [17] using a clock-tickingprocess (Tick) to simulate the passage of time together with a group of global variables to model timerequirements. Two methods, the Sync-based Explicit-time Description Methodusing rendezvoussynchronization steps and the Semaphore-based Explicit-time Description Methodusing only oneglobal variable were proposed [27, 26]; they both achieve better modularity than Lamport’s methodin modelingthe real-time systems. In contrast to timed automatabased model checkerslike UPPAAL[7], explicit-time description methods can access and store the current time instant for future calcula-tions necessary for many real-time systems, especially those with pre-emptive scheduling. However,the Tick process in the above three methods increments the time by one unit in each tick; the statespaces therefore grow relatively fast as the time parameters increase, a problem when the system’stime period is relatively long. In this paper, we propose a more efﬁcient method which enables theTick process to leap multiple time units in one tick. Preliminary experimentalresults in a high perfor-mance computing environment show that this new method signiﬁcantly reduces the state space andimproves both the time and memory efﬁciency.
10472791
Certified Email Delivery with Offline TTP
Email has become a standard communication method nowadays. But when it comes to important correspondences containing sensitive governmental, commercial or medical information, certified delivery is required. We present in this paper a new certified email protocol which assures fair delivery, non-repudiability, confidentiality and timeliness. To achieve definite fairness, an offline TTP is employed which will be involved only if there is a dispute.
1947084
Fair Payment Protocols for E-Commerce
It has been widely accepted that fairness is a critical property for electronic commerce. Fair payment protocol is designed to guarantee fairness in a payment process over asynchronous network. Fairness means that when the protocol terminates, either both parties get their expected items, or neither does. In this paper we first present a new generic offline fair payment protocol with fairness, timeliness and invisibility of TTP. Then we introduce the property of abuse-freeness into electronic payment and implement a fair abuse-free payment protocol.
7625765
Solving QoS-driven Web service dynamic composition as fuzzy constraint satisfaction
The creation of value-added composite web service raises an opportunity to the formation of online B2B collaborations. However, web services are usually overlapping in functionality. How to make a choice based on non-functional factors becomes a problem that needs to be solved. In this paper, it argues that the selection of component services should be considered in a global manner and the user's QoS preferences is more appropriate to be expressed in a fuzzy way. It advocates using fuzzy set to express the user's QoS preference on a specific QoS criteria and using fuzzy expression to express the user's trade-off among QoS criteria's. The service selection problem is formalized as a fuzzy constraint satisfaction problem and deep-first branch-and-bound method is chosen to search for a solution with some adjustments to web service composition. It also develops an uncritical fuzzy consistency checking algorithm as an aid to faster search. Experiments are conducted to prove the effectiveness of the approach.
38699742
Dependable Transaction for Electronic Commerce
Electronic transaction becomes common practice in real world business. This paper focuses on the issue of dependability in critical transactions like electronic payment, electronic contract signing. Recent fair protocols can recover transactions from network crashes, but cannot survive local system crashes. A two-party dependable transaction protocol is proposed. During the protocol, both parties can recover the transaction from network and local system failures in a transparent way, which means that after the recovery, outcome messages would be just the same as those from a successful run of the transaction.
43405539
An Improved Method of Traffic Forecasting Based on Tariff-SASVR
Traffic forecasting is critical for mobile operators to grasp market trends and control network capacity. Therefore, an improved method of forecasting for mobile traffic is presented in this paper. The traffic is divided into the general trend part and seasonal part to forecast them respectively. The general trend is predicted by fitting the curve of general trend on tariff level; and the remaining seasonal part is predicted by simulated annealing-support vector regression machine (SASVR) which uses simulated annealing (SA) to select the super-parameters of SVR. The experimental results show that not only this method improves the prediction accuracy but it provides mobile operators with a visual expression of the relationship between traffic and the tariff level.
27939024
Junction Tree Factored Particle Inference Algorithm for Multi-Agent Dynamic Influence Diagrams
As MMDPs are difficult to represent structural relations among Agents and MAIDs can not model dynamic environment, we present Multi-Agent dynamic influences (MADIDs). MADIDs have stronger knowledge representation ability and MADIDs may efficiently model dynamic environment and structural relations among Agents. Based on the hierarchical decomposition of MADIDs, a junction tree factored particle filter (JFP) algorithm is presented by combing the advantages of the junction trees and particle filter. JFP algorithm converts the distribution of MADIDs into the local factorial form, and the inference is performed by factor particle of propagation on the junction tree. Finally, and the results of algorithm comparison show that the error of JFP algorithm is obviously less than BK algorithm and PF algorithm without the loss of time performance.
14513982
An Online Model Checking Tool for Safety and Liveness Bugs
Modern software model checkers are usually used to find safety violations. However, checking liveness properties can offer a more natural and effective way to detect errors, particularly in complex concurrent and distributed e-business systems. Specifying global liveness properties which should always eventually be true proves to be more desirable, but it is hard for existing software model checkers to verify liveness in real codes because doing so requires finding an infinite execution. For solving such a challenge, this paper proposes an online checking tool to verify the safety and liveness properties of complex systems. We adopt the linear temporal logic to describe the semantics of the finite model checking, use binary instrumentation to obtain the distribute states and apply a checking engine to dynamically verify the finite trace linear temporal logic properties. At last, we demonstrate the method in a distributed system using distributed protocol Paxos and achieve good results by experiments.
5494803
Wireless Network Dynamic Topology Routing Protocol Based on Aggregation Tree Model
As the scale of the network increases, especially wireless and mobile networks comes into fashion, the problem of network dynamic topology management turns into a focus topic in the network world. When network information changes, frequent route computing and network state updates can cause computing and traffic overhead, respectively. Therefore, minimum of influence to network structure has been identified as one of the key issues in designing dynamic network routing protocols. A novel protocol, which is based on Aggregation Tree Routing Model (ATRM) as well as an effective ball-and-string algorithm, is introduced in this paper which aims to minimize the alteration of network topology and to speed up the minimum cost route computation. This routing protocol is applicable to all kinds of networks, including Internet, ad hoc and wireless sensor networks. The simulations show that our protocol not only results in significantly lower overhead, but also gives high levels of dynamic network topology management performance while keeping practical.
694386
A Data Storage Mechanism for P2P VoD Based on Multi-channel Overlay
It is a big challenge to provide Video-on-Demand streaming services over Internet in a scalable way. Currently, many researchers use a single channel overlay to implement the scalability of on-demand streaming services. However, in a real application environment, various channels in a P2P VOD system have different popularities, which probably cause the imbalance of data storage-capability of the whole system. It results in a problem that a mass of unpopular channels' caching capability can not be used to satisfy the data requirements of the whole system. In order to solve the problem, this paper proposes a new data-storage mechanism, which constructs a multi-channel overlay to optimize the whole system's caching-capability and greatly improves unpopular channel's caching efficiency. The experimental results show that this mechanism can achieve significant effects.