Concerning the problem that the data in distributed system usually has many replicas among several datacenters and a robust mechanism was required to maintain data consistency, an algorithm of geographically distributed replication management was proposed after further research on the replication theory of distributed systems. Microsoft Research used Service Level Agreements (SLA) to divide the consistency requirements of users into several levels, each of which was associated with tolerable delay. The system ensured that users could have higher service levels within tolerable delay. Tuba system extends Pileus, it can dynamically change the location of primary and secondary replicas according to statistics sent by all users, so as to raise the average performance of the system. But the replication of Tuba system was carried out based on a single target unit. Improving the method in Tuba system, a set of algorithms independently to change the location of primary and secondary replicas was proposed. The mechanism was implemented in the replication among the HBase distributed systems. After the system is completed, the results show that taking the correlation between two regions into consideration when changing the location of primary and secondary replicas can improve the overall utility of the system.

A reliability evaluation method was proposed to evaluate the reliability of Service-Oriented Architecture (SOA) before its realization. OWL-S (Ontology Web Language for Services), of which the formal semantics of the control structure was defined by Maude, was used to descript the information of software requirements and design. The operational profile of software was built up by distribution function. After this, how the information of operational profile and the architecture of software took part in reliability calculation was added in Maude. At last, the reliability of software could be achieved through rewriting with the supporting of Maude system. In addition, the Software Reliability Predict Tool (SRPT) was developed based on this method. The data flow, control flow, components as well as the operational profile and the architecture of software were considered in the impact on software reliability. According to the design of software, it can estimate the reliability before the accomplishment of software.

Web Ontology Language for Services (OWL-S) model, based on service, plays an important role in software design but it cannot be formally analyzed and verified directly because of its non-fully formalized model. The automatic conversion tool from OWL-S model to rewrite-logic model, which was based on semantic framework of rewrite logic and converted by data types, expressions, control structures and process, was designed and completed. It can formally analyze and verify the design model before software implementation and provide the basis for reliability analysis.