The token economy is a form of decentralized digital economy with the support of blockchain. In the token economy, the responsibility, rights and interests in the real economy can be solidified on the blockchain to form true digital commitments with consensus, tamper-resistance, traceability and verification. These commitments can not only enhance the mutual trust between economic entities, but also realize the isomorphism of real economic activities and digital economic activities. Furthermore, they are conducive to improving the protection of property rights, strengthening the market's allocation of resources, realizing the fair distribution of benefits, strengthening the government's penetrating supervision, and creating a mutually beneficial business environment. Therefore, the token economy is expected to become a new form of digital economy with mutual trust and collective governance. To better illustrate the token economy, this paper introduces the concepts of blockchain, token and token economy, presents the reason why token economy could create a new form of digital economy with mutual trust and collective governance, and finally advances some suggestions on how to develop the token economy.

Personal credit scoring is a fundamental problem in Finance. It has a lot of emerging applications including Credit Card,Mortgage Loan and Automobile Credit, etc. Due to its importance , a lot of personal credit scoring methods have been proposed. Among many other aspects of a client,trade reference is a crucial aspect for an effective credit scoring. In a trade reference,the referee provides a score to describe the credit of the client with respect to the business between the client and the referee. Most existing methods assume that the trade reference is trustable. However,the trade referee may conspire with the client and the trade reference score becomes untrustable in practice. Therefore, in this paper, we propose a trade referee rank to capture both the reputation of the trade referee and the trade reference score provided by the referee. The accuracy of using our trade reference rank is about 40% higher than that of the existing methods. We propose a random walk based method on a client reference graph to compute the trade reference rank of the clients. Our extensive experiments techniques.

There exist many unsolved problems in the traditional digital rights management of network media. For example, in the traditional management system it is hard to guarantee the quality of media works, to protect the copyrights, to find the effective profit model and so on. To solve these problems, we propose in this paper a network media's digital rights management scheme based on blockchain. Blockchain is a technology that makes use of cryptographic algorithm, hash chains and consensus mechanism to implement consensus, irreversibility and traceability for online data. The proposed scheme can use these functionalities of blockchain to implement the effective production management, copyright management, transaction management and users' behavior management for network media. Furthermore, our proposed scheme can predictively provide an important support for the network media platform to build a sustainable development of benign ecological environment.

Blockchain is a technology of recording ledgers in a distributed manner. It uses a consensus mechanism, digital signature and hash chains to realize the reliable storage of ledgers, and provide services such as traceability, integrity and no-repudiation for transactions in ledgers in a decentralized way. These services make blockchain have great application potentiality in the fields of healthcare, Fintech, computational law and so on. Before wide spreading its applications, blockchain must solve problems such as efficiency and privacy. Among these problems the privacy is an important one. Because blocks on blockchain are open, when transactions in blocks involve privacy data, these data can be leaked. Thus, certain security mechanisms must be built to protect privacy data. The core of these mechanisms is the appropriate key management schemes. However, blockchain is a developing technology, and few studies have been done on key management schemes for it. Because healthcare is a big application scenario of blockchain, in this paper, according to the features of health blockchain, we use body sensor network to design a lightweight backup and efficient recovery scheme for keys of health blockchain. Analyses show that the scheme has high security and performance, and it can be used to protect privacy messages on health blockchain effectively and to promote the application of health blockchain.

Graph coloring is a fundamental NP-hard problem in graph theory. It has a wide range of real applications, such as Operations Research, Communication Network, Computational Biology and Compiler Optimization. Notable efforts have been spent on designing its approximation algorithms. Halldrsson proposed the algorithm (denoted as SampleIS) with the current best known approximation ratio. However, its time complexity is O(|G|3), where |G| is the number of vertices of a graph G. It is clear that SampleIS is not practical for large graphs. In this paper, we propose a practical vertex-cut based coloring technique (VColor) for coloring large graphs. First, we partition G into k connected components (CCs) of a small size s by removing a vertex-cut component (VCC). For each CC, we apply our novel coloring algorithm, based on maximal independent set enumeration. The approximation ratio and the time complexity for coloring the k CCs are log s + 1 and O(ks23s/3), respectively, whereas those of SampleIS are ks(log log ks)2/ log3 ks and O(k3s3). For the VCC, we simply apply SampleIS. To combine the colorings of the CCs and the VCC, we propose a maximum matching based algorithm. Second, in the context of a database of graphs, users may color many graphs. We propose an optimization technique, inspired by multi-query optimization, for coloring a set of graphs. We design a VP hierarchy (VPH) to represent the common subgraphs as the common CCs. Third, we propose techniques for determining the optimal values of the parameters of VColor. Our extensive experimental evaluation on real-world graphs confirms the efficiency and/or effectiveness of our proposed techniques. In particular, VColor is more than 500 times faster than SampleIS, and the number of colors used are comparable on real graphs Yeast and LS.

Body sensor networks (BSNs) are deployed around the human body to measure and process physiological signals in real time, which have wide application prospects in intelligent healthcare. Physiological signals measured and processed by BSNs involve individual privacy, thus security mechanisms must be developed to secure BSNs, and therein adoption of key negotiation protocols is fundamental. Due to stringently limited operation resources, BSNs require these protocols to be low-energy and highly efficient. Recent development has discovered that certain physiological signals can be used for efficiently negotiating common keys among biosensor nodes. These signals and fuzzy technology are used to design lightweight key negotiation protocols, and many solutions have been proposed. In this paper, we explore and classify these solutions, and evaluate their performance by analyzing their merits and demerits. Finally, we present open research issues that should be solved in the future.

Tourism service composition combines various tourism elements for users, including transportations, catering, accommodation and other tourism service elements, in order to generate a one-stop tourism service that meets multi-objective needs of users. In doing this, it should simultaneously consider the historical travel data and the current preference of user to complete the composition. In addition, the composition process should be efficient enough to return results online for users in real time. In this paper, we establish a model of tourism service composition based on multi-objective optimization according to the parameters of tourism services. In particular, this model involves three optimization objectives: time, cost and quality of services. We then propose a single-objective-based optimization algorithm to effectively and efficiently solve the tourism service composition problem based on multi-objective optimization. Experimental results demonstrate that, in comparison with the particle swarm optimization-based multi-objective optimization algorithm, our approach can obtain more accurate results and achieve the significant improvement in optimization efficiency.

Service-oriented computing and Web services are becoming the dominating computing model as internet and cloud computing become pervasive. More and more services with the same functionality are becoming available, and QoS (Quality of Service) is the main factor to differentiate them. The overall QoS of a business process must meet user's requirement. Our study proposes a proxy-based framework to facilitate the dynamic integration of Web services into business process and fast detection of abnormalities. The major functions of our dynamic proxy-based framework include service collection, composition, selection and adaptation. Our study concerns both functionality and QoS characteristics of Web services to identify the optimal business process solutions.

Many Websites on the Internet are based on database, especially Websites which use database to display the pages actively such as ASP, PHP and JSP. However, because of SQL attack, people pay much attention to the security of database on the Internet. Different from many protection systems deployed between Web servers and Internet, this article designed a database protection system between Web server and database server. It parses network and database protocol of the packets passing through, and extracts the SQL statements, then analyzes and filters the SQL statements, so it protects the database effectively on the application layer and its effectiveness is independent of any particular target system, application environment, or DBMS. Even there is no need to modify the source code of existing Web applications. This system has been carried out in application and has good effect.

Some heterogeneous security equipments such as firewalls, intrusion detection systems, and anti-virus gateways, can produce massive security events which are difficult to manage efficiently. So a log-based mining, distributed, and multi-protocol supported framework of security monitoring system is proposed. This paper describes the architecture of the information security monitoring system, and focuses on the research of the correlation analysis engine, describes the process that the detection model is built using data mining techniques. Security event correlation based on data mining analysis can automatically extract association rules, analyze alarming and found new invasion model, so it is a highly intelligent solution.