| Internet of Things (IOT for short) is called the third wave in the world's IT industry after the computer and networking. Simply,its meaning is to connect any items with Internet to realize the remote monitoring.IOT will be a new era of networking for people living in new experience. Wireless sensor network (WSN) is an important part of IOT, and also a hot research field currently. Since 1978, Carnegie Mellon university study of distributed sensor network - wireless sensor network appeared, WSN has been widely applied in the natural environment and human physiological monitoring data monitoring, pharmaceutical and food storage management, animal management, intelligent household etc. As intelligent village, intelligent household spring up, it promoted the change meter associated technology, and made the meter measuring way gradually transited from artificial intelligent automation. WSN technology will be applied to meter measuring meter, which helps to improve work efficiency and accuracy. However,each sensor node is an embedded system, due to some factors of physical limit, its processing and storage capacity is relatively weak, so it must rely on the distribution of transfer data nodes. Each sensor node must relative dense. Therefore, only to reduce the cost of sensor nodes, can make the technology more popular. Only the node's real-time response ability improve, can complete emergency work. I believe with sensing technology, wireless transmission technology, wireless network technology, automatic control technology and other related technical improved, wireless sensor network technology will spread to all sorts of meter measuring to bring great convenience for people.WSN system consists of a lot of sensor nodes, sink nodes and management node. Wireless sensor network realization process: First, random or on-demand placed the sensor nodes in monitoring area (artificial resettlement, plane dropped, etc). Each sensor node scattered around other self awakening, monitoring of sensor nodes, using certain network algorithm, formed a certain rule of the network. Then, sensor nodes use multihop routing, rely on other nodes distributed around them to transfer data, and finally will converge to sink nodes. In the last place, through the gateway, sink nodes connected to the Internet or satellite, and transmit to the distant user management node. So users can real-time communicate with the sensor nodes.This paper designs and realizes the wireless sensor network layout, using wireless sensor network construction principle: Multiple intelligent wireless terminals,that is gas meter using star structure connect to wireless router wirelessly, wireless routings using tree structure wirelessly connects to base stations, then base station through Internet by virtual private network (VPN) connected to the remote control center server. Finally end-user applicates by meter measuring data can check the remote control of intelligent wireless terminals working condition etc.Intelligent Gas Meter Reading System, which is designed and realized by this paper, consists of six sub-systems: wireless network control and management system, hand-held terminals application system, front-end system, operating systems, systems management and billing system analysis. Each sub-system adopts independent design. The main functions are: Basic management, management, data query role management, statistics and abnormal data analysis, gas meter management, expends input management, business management. This system can effectively help prevent Gas Company, gas discharge fault phenomenon, such as copy, timely and accurate metering, and check WSN remote gas meter running state and on WSN remote control.This paper mainly introduces the analysis, design and implementation of the role management module of system.Firstly, this paper makes a detailed analysis on the gas company requirements to the permission management of system. According to customer needs, it abstracts the use-case model, and then does the field model analysis and work flow analysis. For such a comprehensive management system of meter is used in different departments of the company, different levels or the position of the system operators, different system operators access the information system should be different. So the practicability of the safety management of construction in this system must be most considered. Through analyzing present various access control model, according to the actual needs of the system, I decided to adopt the currently accepted, effective access control model - role-based access control (RBAC) to design character management module. In RBAC model, the role as a strong communication link between users and resources, users'access permission transforms role permission. Then link users with the role, which has particular permissions, and finally uses get the permission. This is not only a clear responsibility and permission to users, but also to strengthen the safety managements of the system resource, simplified systems. Moreover, the system administrator can use a similar method popular in enterprises in reality.The basic elements of RBAC are user, object, roles, operation, and permission. No consideration"operation"in RBAC, because for the system user needs has no specific operation.Secondly, according to user requirements and RBAC model, this paper designs the related entity class, management class and interface class of the role management. Given the class diagram of the various kinds and described. And done the user interface design and database design. In the user interface design, it uses the pattern that custom controls can be reused in code page. In data query, it uses the breakthrough innovative technology- LINQ to SQL designer in .NET3.5, directly using c # langue can query data without writing the code access the database. The Relationship between LINQ to SQL object model and SQL Server database mapping is: The entity class in LINQ to SQL object model mapping the table in the data base, members of the class mapping the column in the database, the instance of class mapping the row in the database, the correlation between classes mapping the foreign key relationship between classes in the database, the methods mapping process or storage in the database.Finally, after introducing the form validation and the realization of the API of role management, using HTML, CSS and JavaScript technology to achieve the function of the user interface of the role management, and give the related screenshots. |
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