Design And Implementation Of The RDF-Based Publish/Subscribe System

In recent years, with the trend of the integration of logistics services becomes stronger, a lot of supplier, broker and customers on the logistics supply chain demand for seamless service, which put forward higher requirements to enterprise for the timeliness and reliability of the information. Greatly accelerated in e-commerce operation of the business activities require the participants to break through time and space in a limited manner in order to facilitate transmission of information to work. The publish/subscribe technology has greatly facilitated information exchange between the parties, enabling them to customize and personalize the information, which is the ideal choice of today's e-business environment.However, the existing publish/subscribe system still exist some problems in terms of the expression ability, efficiency and reliability, so it's difficult to support large-scale information exchange environment. This paper works on the key technology of the publish/subscribe system it the field of logistics-oriented environment, constructs a semantic ontology library of the logistics services, designs a RDF based event-subscription model and matching algorithm, and implements a publish/subscribe system, which can either directive used by existing logistics platforms or external systems. This publish/subscribe system has better expression ability, maintenance capabilities, matching efficiency, and scalability. Specifically, this paper includes the following content:First, the paper designs and implements a message module which can catch and forward business message. This module is a bridge between end users, and provides support mechanisms to ensure the smooth of the business processes. The module provide a classified subscription and distribution mechanism for message, allowing users to subscribe according to their own needs and rules of different types of messages. The system can filter and mapping messages by using some keywords and simple matching rules.Secondly, based on some related concepts extracted from the logistics domain, the paper designs a commonly used logistics domain ontology model, in order to achieve a more flexible semantic subscription expression function. The relevant semantic expression ability involved mainly including the concept of inheritance semantics with the coverage and the concept of logical relationship with the field of semantic association. By extracting and designing the ontology library, allows users to break the theme keywords constrains and subscribe on a more flexible way. Specifically, it can help the subscribers express their interest more accurately.Finally, there are generally a large number of participants in the publish/subscribe systems, and the information exchange between them is also very frequent, therefore we need an efficient matching algorithm. The paper constructs a versatile event/subscription model which based on the Resource Description Framework (RDF), and implements an efficient matching algorithm based on semantic. The algorithm uses the RDF model's characteristics to splitting the metadata to establish a multi-layer indexing structure. Taking advantage of the multi-hash table and the characteristics of binary sort tree, we can reduce the double counting and enhance the search and matching efficiency.Through the application of the publish/subscribe system, we can provide both information sharing and transmission mechanism for logistics service providers, logistics broker and users, and also references for the business choose, that is an integral part of the entire business process. At the same time, the personalized subscription and filtering information mechanism, allow users to get what they need in the information massive flood quickly, stringing the whole services sectors of the logistics supply chains together as a whole.