無線傳感器網(wǎng)絡(luò)和災(zāi)害天氣報警系統(tǒng)

1、A Wireless Sensor Network for Weather and Disaster Alarm SystemsCholatip Yawut+ and Sathapath KilasoFaculty of Information TechnologyKing Mongkut's University of Technology North Bangkok, Bangkok, ThailandAbstract. In the last few years, the occurrences of natural disasters have been continuing

2、changing our1. IntroductionNatural disasters are becoming more severe. One important reason is the results of global warming around the world causing many of the disasters. To carefully protect people in these areas, we need a monitoring and alarm system. In many events such as landslides and water

3、flooding, they can be warned by a raised alarm within in a specified period. The surveillance systems equipment is a tool used to measure parameters such as sample temperature, air pressure, moisture, vibration etc. These parameters will vary depending on the requirement of the surveillance system.M

4、onitoring system, the equipment used for detection is the heart of the work. The monitor system devices are installed in different places. Sometimes it is not easy to install equipment in some areas for many reasons such as lack of access to power or unable to connect to signal wiring. In addition,

5、tools used for measurements are very expensive. To resolve this problem, a wireless sensor network can be implemented to help in data communications. The advantages of using a wireless network are: using less energy, no need for hardwiring, and high transmission distance.In this research, the advant

6、ages of a wireless sensor network are taken to benefit weather monitoring stations. Many sensor stations measure and send parameters through a wireless network server. Or if the station is outside the servers radius, it can send data to the nearest wireless weather station forwarding the data to the

7、 server. In addition, the wireless sensor network is easy to maintain, devices are cheaper and uses less energy.Today, the wireless sensor network is cheaper and more efficient then other systems, the high flexibility can be used in various ways depending on the need to measure different values in t

8、he environment, it can be used to measure the amount of carbon dioxide using gas sensors. In structure measurement, it can measure the motion of buildings. Or in the military, it can be very important as it uses a large number of sensor nodes to scatter in battlefield to measure temperature, vibrati

9、on and movement of enemy spies and so on.In other research, the application of a wireless sensor network system are employed in fields such as medical, 1 proposed an application as Personal area network system for monitoring of a patient's heart, In agricultural, 2 used the wireless sensor netwo

10、rk to check and control the greenhouse effect from+Corresponding author. Tel.: + + 6629132500ext2728; fax: +6629122019. 2011 International Conference on Information and Electronics EngineeringIPCSIT vol.6 (2011 © (2011 IACSIT Press, Singaporetemperature, humidity, light parameter and record wea

11、ther statistics for planning, and 3 presented the development of a wireless sensor for use in various applications.This research uses arduino microcontroller board 4 and Xbee module to create a wireless sensor network using decision tree to analyze the weather data and to alert when it matches with

12、pre-conditions.2. Related Works2.1. Decision TreeA decision tree, 5 is a diagram that a decision maker can create to help select the best of several alternative courses of action. The primary advantage of a decision tree is that it assigns exact values to the outcomes of different actions, thus mini

13、mizing the ambiguity of complicated decisions. Because they map out an applied, real-world logical process, decision trees are particularly important to build "smart" computer applications like expert systems. They are also used to help illustrate and assign monetary values to alternative

14、courses of action that management may take.In this research, the use of a decision tree will process input parameter to alarm when an inputted parameter matches predefined conditions.2.2. Zigbee Standard2.3. XBee TopologyTo create a wireless network of ZigBee, it will consist of at least two nodes i

15、ncluding coordinator node and sensor node types (Router/End device to be able to communicate and work in PAN (Personal. area network. Wireless sensor network topology an be divided into 3 topologies: Star Topology (Fig. 1-a,Cluster Tree Topology (Fig. 1-b and MESH Topology (Fig. 1-c. (a Star Topolog

16、y(b Cluster Tree Topology(c MESH TopologyFig. 4: Wireless Network TopologyStar topology or a Broadcast is non-specific transmission. All destinations or on the same network can Get all the information any time (Fig. 1-a.The transmission of data transmission, such as E0 need contact to C0, but C0 is

17、far from E0 and E0 can connect to R0, and R0 is between E0 and C0, so Cluster Tree will use R0 as an intermediary (Repeater connecting the 2 nodes C0 and E0 (Fig. 1-b. Mesh topology is the most effective since data can be sent to the target in more ways; it can transfer data to a destination even if

18、 parts of the system are lost (depending on system design (Fig. 1-c. Mesh networks 3 are regularly distributed networks that generally allow transmission only to a nodes as peer-to-peer (see below nets. Mesh nets can be good models for large-scale networks of wireless sensors that are distributed ov

19、er a geographic region, e.g. personnel or vehicle security surveillance systems. Serial Interface ProtocolsXbee module supports both transparent and API (Application Programming Interface serial interfaces. - Transparent Operation: when operating in transparent mode, the modules act as a serial line

20、 replacement. All UART data received through the DIN pin is queued up for RF transmission. When RF data is received, the data is sent out through the DOUT pin.- API Operation: API operation 8 is an alternative to transparent operation. The frame-based API extends the level to which a host applicatio

21、n can interact with the networking capabilities of the module. When in API mode, all data entering and leaving the module is contained in frames that define operations or events within the module.3. System Design and ImplementationOur wireless sensor network for weather and disaster alert system use

22、s mesh network topology. The system design is divided into two main sections consisting sensor node (Router/End Device Node andcoordinator node (Fig. 2. Fig. 2: System overview consists of Router/End Device Node and Coordinator Node.3.1. Sensor NodeThe sensor node consists of the microcontroller, te

23、mperature and humidity sensor, light sensor, pressure sensor and XBee module (Fig. 3-a shows sensor node block diagram. The wireless sensor nodes are programmed with C language (for Arduino 4. It stays on standby for requests of data transmitted from the server (coordinator with server. Upon receivi

24、ng the request for weather data, the microcontroller will read the data from different sensors and send the data back to the server (Fig 4-a. shows the flowchart of sensor node process.This experiment is set up with XBee module working in mesh topology. For data transmission, it has only one sensor

25、node which is the coordinator with server for data recording and processing. For the transmission to coordinator, sensor nodes cannot directly contact the coordinator, it needs to transmit data to sensor nodes near the coordinator. (a Sensor Node block diagram(b Server and coordinator node block dia

26、gramFig. 3: System block diagram.In the API Frame type, it can check whether the data has been sent to the server or not. When the sensor sends data out, the server will receive it and send API Frame back to show completed state. Otherwise, it will retransmit such as the destination offline.Coordina

27、tor NodeRouter/End Device Node (a Sensor node process(b Server node process.Fig. 4: Flow chart of Sensor node and Server node processes.3.2. Server and CoordinatorOn the server side, it has a web/database and connects with XBee (Fig. 3-a shows server and coordinator node. The server has an applicati

28、on and web application to control and to manage the system. The server will connect XBee via USB port. When opening the application and selecting serial port to connect to the XBee sensor nodes, the system will search sensor nodes in the network and display the status and data of the sensor node.Req

29、uested data from the sensor node, the server will be sent API Frame via sensor nodes. When the data is sent out, the status of delivery will change if the sensor node successfully receives the data. But if there is no response from the sensor nodes, the system will again send the request data in a s

30、pecified period. (Fig. 4-bWhen the server receives weather data from sensor nodes, the server will check the weather data with notification value by using decision Tree techniques. If it matches with the pre-conditions, it will notify thesystem administrator and record of the notification and automa

31、tically store weather data to the database. Fig. 5: Application interface.3.3. ApplicationIn this section, Visual studio C# is selected to develop an application used to control and display the information (Fig. 12. The application consists of six main parts; 1 Home: Main page, 2 Statistics: Display

32、 node information, weather and operation information 3 Alert setting: Configuration and add conditions of the notification 4 Device: Management device in network including add, edit and delete 5 Config: Setting the display and 6 About:About this application.3.4. ResultsThe alarm system, we used deci

33、sion tree to analyze and process the data. Each parameter has 2 boundary values in decision tree process. Testing of the system used black-box testing to test the performance and accuracy of the system. In Table 1-a shows the boundary values and Table 1-b is the expected output with real output. In

34、this testing, rainfall and wind speed are simulated parameters. Testing results confirm that the system perfectly works.Table 1: Boundary values and Testing Results.(a Boundary values used in decision tree process (b Comparing expected output with real outputon Boundary valueT 0T 1H 0H 1P 0P 1L 0L 1

35、R 0R 1W 0W 1200 30200 30200 30T is temperature, H is humidity, P is pressure, L is light, R is rainfall, W is wind.onReal Output Expected outputT e m p e r a t u r e °CH u m i d i t y %P r e s s u r e m m H gL i g h tR a i n f a l l m m .W i n d s p e e d K m /sAlarm Alarm Alarm Alarm 34Alarm Alarm 33AlarmAlarm4. ConclusionIn the field testi