The February 2007 Instrumentation

Transcription

1 Andrzej Kalicki, Łukasz Makowski, Andrzej Michalski, and Zbigniew Staroszczyk Distributed Measurement Systems A Web System Approach: Part 1 The February 2007 Instrumentation Notes column of The I&M Magazine described a wireless hydrocarbon pollution measuring and monitoring system [1]. That column focused on the hardware solution of the sensor side of the countrywide measuring system and introduced the software. The system was developed at the Warsaw University of Technology and gives Internet access to the network of sensors that monitors hydrocarbon pollution in sensitive areas of Poland. The system has the ability to track 20 different regions (i.e., water reservoir of a city, petrochemical plant, oil ship at the port) that are monitored by up to 10 mobile observation points (MOPs). MOPs are the measurement devices. The MOPs communicate through the Global System for Mobile Communications/General Packet Radio Service (GSM/GPRS) links with the central server. The central server provides a database service for Supervisory Clients (SvClient), who have access via Internet browsers. It offers a great flexibility of solutions (Figure 1). The hydrocarbon monitoring system uses software for SvClient access information and for the server. The software will be discussed in the following groupings: Three stages of Windows software development based on Visual Studio.NET: The field system functionality testing software (FSFTS) used to create the system; the thin SvClient/Server without additional support; and the thin SvClient/Server with additional Internet-provided support; This column presents the first, proprietary software approach, its main advantages and disadvantages. The GUI is also discussed. The GUI allows the SvClient to access the system data and control. From the user s point of view, the system is the Internet/web application of the distributed measuring system [2]. The terminals are the autonomous MOPs [3]. Another software application in a server solution that is based on free and open source software will be described in the December 2008 issue of The I&M Magazine. Windows System Approach The Windows Visual Studio 2005 offers great flexibility in web applications development with the use of ASP.NET. The Windows Visual Studio Integrated Development Environment (IDE) forms an interesting alternative to UNIX web development tools, as it has direct access to the Windows GUI and databases. The Microsoft IIS server, which runs the application, can be installed on Windows XP as well as Windows Server 2003 operating systems. The additional advantage of the Windows approach to a server is the Visual Studio ability to program web services on mobile platforms. With the Mobile Application Development, alarms can be sent to and served by mobile phones and palmtops to assure quick response of emergency teams to abnormal situations. There are authentication and authorization measures that assure the security of web applications. The Visual Studio software system structure is presented in Figure 2. The main assumptions are that the application is web based and that the server has a thin client solution, which would allow everybody to get information from any place and with any operating system. The server receives the series of measurements from the MOPs and they are intercepted by a special listener. We used a server with a listener function based on Windows 2003 as a special Windows service. Fig. 1. The distributed measurement system. 50 IEEE Instrumentation & Measurement Magazine April /08/$ IEEE

2 Fig. 2. The software structure of the Windows approach developed system. The listener uses a defined socket (port and address), receives incoming strings, parses them with a special algorithm, and stores the parsed portions of data in the database (MSSQL 2005 Express Edition). Our database is located on the same machine as the listener. In principle, the database can be located in any other computer with Internet access. In the database, all data are stored with all supplementary information: the specific MOP they came from, when they were delivered from the MOP, the value of measurement, and the location of the MOP as obtained from the GPS module. All these data are used by the IIS Web server, which dynamically creates all pages to the supervisor client s (SvClient s) requests. The script language used here is ASP.NET version 2.0. Three stages of Windows software development are presented here: the FSFTS, thin SvClient/ Server, and thin SvClient/ Server with additional Internet-provided support. The FSFTS At the very early stage of measuring system infrastructure development, the field system functionality testing software (FSFTS) was built using Borland Builder C IDE. The FSFTS tests the functionality of the final system, with the use of the local client/server software, which could be run on any Windows-equipped machine with Internet access. We used the FTFTS to test the Internet/GSM/ GPRS socket communication with MOPClients and to verify functionality of SvClient service. Fig. 3. The FSFTS control screen University located MOP observation. April 2008 IEEE Instrumentation & Measurement Magazine 51

3 continued The accepted string data are written to Software FX Activex object and are accessible to the operator in a graphical window with plenty of real-time settings (color, two-dimensional/ three-dimensional, interpolation, etc. (see Figure 5). The Software FX Inc. graphics allow for multichannel, interactive data observations for the memorized historical data (see data slider at the bottom of Figure 5) and have a rich set Fig. 4. The maps with three active MOPs location areas, focused on the Krakow area subset of MOPs. of controls for two-dimensional and three-dimensional data presentations. The company software is offered for Borland Builder, Visual Studio.NET, the Internet, and other programming platforms. The FSFTS was used successfully in the first stage of system development, when the full client-server-client system structure was not built. Currently, it is used in real field applications for testing purposes. With the GSM-equipped PC, the system testing software can be run at any time and in any place in Poland; it delivers full working information on system behavior. Such information is only accessible to the system administrator in the final system solution. Fig. 5. Typical GUI of the Software FX graphic Activex library.mops. The FTFTS is the Windows application that (on both the open socket and fixed IP) listens to service requests from MOP- Clients, organizes and maintains bidirectional data links with them, and allows for full control of the operator on the currently active MOPs structure. The FSFTS has the client/server properties and is the only software module required to make the whole system run. The essential part of the FSTFS GUI is the interactive map, which shows the currently active MOPs positions (Figure 3). The maps have a pyramidal, five-layer, zoom 10 structure (Figure 4) and cover the country area (1,000 1,000 km, first layer map) and a priori chosen locations presented on more detailed maps, leading to maps with the highest resolution: m (the set of fifth layer maps). A user can activate an area of interest with a mouse click on the country map MOP position. All subsequent up/down zooming and program focus will be on the chosen set of MOPs (i.e., Krakow in Figure 4). The software user, MOPClient, starts a process of real-time interaction with the server by activating the higher level maps MOP positions. Incoming data strings are verified and parsed if they are not erroneous. Errors are signaled and logged on request. The Server Based on Visual Studio.NET The final system is web based. It is server thin client accessible and allows all MOPClients from any place in Poland to get the sensor data that are collected. The system is equipped with a professional database, which serves as the only data source for SvClients (thin client) requests. The database service is separated from direct access to the MOPs and SvClient requests. The MOPs have direct access to the Windows service (MOPService) responsible for maintaining the MOP-database communication. The SvClients have access to the database through ASP.NET-generated pages in SvServer. Currently two versions of SvServer were developed, those with and without additional Internet support on the client side. In the current software solution, when the user launches the web page (SvClient), he gets three choices for obtaining different statistics and information on MOPs: The first choice is the location of the MOPs. The location is indicated on the map with hotspots of current MOP positions. Clicking on the MOP gives additional information on MOP geographical position. For further development, a new page will be opened with the graphical/text information. 52 IEEE Instrumentation & Measurement Magazine April 2008

4 Fig. 6. (a) First level map the whole country; (b) km map; (c) 1 1 km area map; and (d) the highest resolution, m map. The second option is to get measurement results and supplementary data for every MOP. The data can be filtered for one MOP or chosen date. Filters are created from a dropdown list, which is created from the database from the server. The requested data are presented in easily read tables. The third option will draw a graph of the data from a chosen MOP. The user chooses a MOP from a dropdown list and then enters the start and the end times. Further development will deliver web-based panels, which can be used to administrate MOP (i.e., disable measurements, change the system sampling rate, enable measurements, etc.). Thin SvClient/Server without Additional Support This version of the service assumes that all data processing is made on the server side. The client gets HTML documents with built-in graphics and controls. No JavaScript or Java applet support is required on the client side of the system. The three kinds of activity of such SvClients are presented below: Map presentation: The map service is very similar to the FSFTS solution. There is a slightly different zoom control, with the use of zoom in or zoom out radio buttons (Figure 6). By activating the Gdansk (northwest) position on the first level map, the SvClient passes through subsequent maps to the detailed map of the area of interest (the pier of the Gdansk port). The MOP activation on the higher level maps gives its short description [Figure 6(d)]. If the Data radio button is active, the data textual presentation of the selected MOP is activated if the user clicks on it. Textual data presentation: In that mode, the tables with data are generated on the server side with the use of stored procedures and are sent to the client. Only one page of results is shown on the client screen. The client can choose the date, sensor, page size, and page number of interest. Therefore, any part of database-collected data can be analyzed relatively quickly (Figure 7). For example, access to page 300 of the long data dump is almost immediate [Figure 7(b)]. Graphical data presentation: The graphic is generated on the server side with the use of standard ASP.NET libraries and a self-made drawing program. The user can easily narrow or expand the displayed period using time and date indicators [Figure 8(a) and (b)]. Thin SvClient/Server with Additional Support This solution of ASP.NET SvClient/Server software uses the Microsoft Excel graphic support on the server side and Google Maps support on the client side. The MOPs positions are presented on flexible world area interactive maps with map/satellite view presentations built into the Google Maps. April 2008 IEEE Instrumentation & Measurement Magazine 53

5 continued Fig. 7. Textual data presentation: (a) first page from total of 329 pages for sensor nb 1 data dump; (b) the page 300 of the same day/sensor data.resolution, m map. Fig. 8. The example graphics generated on the server side: a) graphical data only; b) graphical and textual data. The graphical plots of data are fully flexible, with auto-scaling and auto-description built into Excel graphics. Maps: The Google Maps supported maps allow for flexible focus on any world position; however, the maps offer limited Google Map resolution in some locations. However, the sensor position presentation and selection [see Figure 9(a) through (d)] here are much more flexible and user friendly. There is no problem with zooming, and the selected map/satellite/hybrid presentation is of great value to the operator. Textual data presentation: The presentation does not differ from that described previously [1, 2], except for the fact that there is an added calendar. 54 IEEE Instrumentation & Measurement Magazine April 2008

6 Fig. 9. Zooming procedure using Google Maps: a) country level; b) town level; c) street level; d) block level. Graphical data presentation: The new graphics are quite different. The principal property of these graphics is that they auto-adjust to the presented data. Not only scales but the axes description automatically adapts to presented data, giving a readable drawing on the client screen. One can observe that in spite of wide left and right side presentation margins ( / ), the plot in Figure 10(a) adjusts to the 26 November 2007 data [Figure 10(b)], which are the only data that exist for the chosen sensors/period in the database. Free and Open Source Software Approach Universally in our system, we can distinguish several hardware layers: measuring nodes, wireless connections, database, and visualization clients. Because are using GPRS/GSM as the wireless link, we have to rely on telecom provider infrastruc- April 2008 IEEE Instrumentation & Measurement Magazine 55

7 continued system are based on a Windows operating system. The first solution implements Microsoft s.net environment. The second one uses WAMP (Windows and free and open source software: Apache, MySQL, and PHP). The main difference between the first two solutions is how the client page is generated. The.NET case is only on the server side, and the WAMP case is on both server and client sides [1]. Both systems produce a map/plot/ table showing the system data to the user through web browsers. Each solution has advantages and disadvantages. Users have not yet rated one system above the other. References [1] A. Michalski, A wireless hydrocarbon pollution measuring and monitoring system, Instrumentation Measurement Magazine, vol. 10, pp , Feb [2] A. Michalski, A. Kalicki, Z. Staroszczyk, and P. Pietruszka, Development problems of large area, web accessible, environmental pollution monitoring system, in Proc. 24th IEEE Instrumentation and Measurement Technology Conference, Warsaw, Poland, May 2007, pp. 19, 65. [3] B. Dziadak, A. Kalicki, Ł. Makowski, A. Michalski, and Z. Staroszczyk, Sensors networks for petroleum derivative pollution monitoring system, Maintenance Problems, PIB Radom, vol. 63, no. 4, pp , Andrzej Michalski (anmi@iem.pw.edu.pl) is a professor of electrical engineering at the Warsaw University of Technology and at Warsaw Military University, Poland. He is a vicedirector of Institute of the Theory of Electrical Engineering, Measurement and Information Systems at Warsaw University of Technology; he has published approximately 130 journal and conference papers. His current research interests include sensors dedicated to nonelectrical quantity measurements by electrical methods. He is a Senior Member of the IEEE Instrumentation and Measurement Society. Fig. 10. Graphical data presentation: a) zoom for 6 days; b) zoom for 10 minutes. ture of hardware and software as well. However, in every other part we can use software of our own choice. We will describe the other server solution based on free and open source software in the December 2008 issue of The I&M Magazine. Summary As a starting point to the discussion, the simplified (all-in-one) FSFTS was presented. That software was successfully used for verification of the final system functionality and the quality evaluation of its components. Then, two solutions for the server/client software for the distributed measurement system, implementing the web as a main transmission medium, were described. The essential parts of the final system solutions are the server and the clients. The server collects remote data and makes them accessible for clients. These two solutions of the server/client Andrzej Kalicki is an assistant professor at electrical engineering faculty at the Warsaw University of Technology (Warsaw, Poland). He has published over 30 journal and conference papers. His current research interests concern measurement systems, telemetry, and measurement data processing. Łukasz Makowski works as an assistant lecturer at Warsaw University of Technology, where he is completing his Ph.D. thesis. His main areas of interest are distributed measurement systems as well as free and open source software. Zbigniew Staroszczyk is an assistant professor of electrical engineering at the Warsaw University of Technology and at Warsaw Military University (Warsaw, Poland), where he teaches courses and conducts researches in microcomputers, DSP, and computerized measuring systems. His main research activity is power systems oriented DSP. He is a Member of the IEEE Power Engineering Society. 56 IEEE Instrumentation & Measurement Magazine April 2008