1、 附录 A WirelessFoodOrderingSystemBasedonWebService AbstractCurrent wireless communications enable people to easily exchange information, while web services provide loosely-coupled and platform-independent ways of linking applications across the Internet or Intranet. This paper presents an integration
2、 of wireless communication technologies and web services technologies to realize a wireless food ordering system. In this system, it implements wired and wireless data access to the servers and food ordering functions through both desktop PCs and mobile devices such as PDAs over a wired/wireless int
3、egrated local area network. To sure the security of the system, the secure web service architecture and some security strategies to ensure mobile communication security are discussed. Web services-based wireless applications on mobile devices provide a means of convenience, improving efficiency and
4、accuracy for restaurants by saving time, reducing human errors, etc. Keywords Web Services； Wireless； Food Ordering System； security I. I NTRODUCTION The rapid developments in information technology, particularly in wireless communication and web services technologies, are greatly changing the way p
5、eople access and work with information. The convenience and powerful functionality offered by mobile devices such as PDAs, has encouraged many people to investigate the benefits of using them. Wireless and handheld devices abound as vendors pitch the common themes of one-to-one computing, instant co
6、mmunication and anytime, anywhere information access. While web services provide a technology for service-oriented computing. Web services allow programs written in different languages on different platforms to communicate with each other in a standard way . By integrating these technologies, consis
7、tent business models can be implemented on a broad array of devices: not just on mobile devices operating over mobile networks, but also on servers and PCs connected to the Internet. The food ordering process in restaurants requires the coordination of simple tasks. Instruction flows mainly from cus
8、tomers to waiters then to kitchen and/or the bar staff, finally to the cashier . In a medium to large and busy restaurant this coordination is a challenge and requires an efficient ordering system. Errors in ordering processes lead to incorrect or out of sequence meal preparation or non-consumable a
9、nd results in added cost to the business. This paper presents an integration of wireless communication technologies and web services technologies to realize a wireless food ordering system. In this system, it implements wired and wireless data access to the servers and food ordering functions throug
10、h both desktop PCs and mobile devices such as PDAs over a wired/wireless integrated local area network. The system is based on secure web service architecture and some security strategies to ensure mobile communication security are adopted. Web services-based wireless applications on mobile devices
11、provide a means of convenience, improving efficiency and accuracy. II. W IRELESS LAN AND W EB SERVICES A. Wireless LAN A wireless LAN (WLAN, Wireless Local Area Network) is a flexible data communication system implemented as an extension to or as an alternative for, a wired LAN within a building or
12、campus . Using electromagnetic waves, WLANs transmit and receive data over the air, minimizing the need for wired connections. Thus, WLANs combine data connectivity with user mobility, and, through simplified configuration, enable movable LANs. The IEEE 802.11 group of standards specifies the techno
13、logies for wireless LANs. 802.11 standards use the Ethernet protocol and CSMA/CA (carrier sense multiple access with collision avoidance) for path sharing and include an encryption method, the Wired Equivalent Privacy algorithm. The 802.11a, b, and g standards are the most common for home wireless a
14、ccess points and large business wireless systems. A remote user can use WLAN to access the Internet through public access points (“hotspots”) provided by service providers. When in the office, they may access WLAN through wireless access points. In enterprise environments, WLANs are usually compleme
15、nted by security mechanisms, such as VPN (Virtual Private Network). Over the last several years, WLANs have gained strong popularity in some markets, including the health-care, retail, manufacturing, and academic areas. These industries have profited from the productivity gains of using hand-held te
16、rminals and notebook computers to transmit real-time information to centralized hosts for processing. Today WLANs are becoming more widely recognized as a general-purpose connectivity alternative for a broad range of business customers. B. Web Services Quickly becoming a significant technology in th
17、e evolution of the Internet is web services, a set of standards that can interconnect systems over a verity of networks. It is an open XML-based technology providing a generic data exchange format and has been rapidly adopted by many vendors. Web services can easily be built upon existing applicatio
18、ns, no matter what the underlying technology is. Because they are expected to have a growing familiarity and acceptance among many users and offer great technological promises, Web services are an interesting subject for the investigation of their possible application in many systems . Web services
19、are a new generation of web application. It combines the advantages of the component-oriented methods and web techniques, and they can describe its own service. It can also publish, locate and transfer modularized application in web. The provided functions of web services may be simple, but it also
20、contains extraordinary complicated business logic. Web services represent a kind of implementation of SOA (Service-Oriented Architecture), and they are the most popular one. In addition, the three operations of SOA can only process when the components of SOA interact. Therefore some standardized tec
21、hniques are used in web services, including UDDI, WSDL, HTTP, SOAP, and XML and so on. Web services become the best choice for developing application of SOA . III. DESIGN AND I MPLEMENTATION OF THE SYSTEM A. System Architecture In the system, we adopt four-tiered web-based client-server architecture
22、. Figure 1 shows the overview of the system architecture. The system is conceptually composed of six main components: the web server, database server, cash register, mobile context server, mobile user and desktop user. The web server provided relevant information for mobile devices or desktop PCs on
23、 a wired/wireless integrated local area network using WSDL (Web Service Description Language) to describe functions and protocols. The web server then transmits to the mobile devices or desktop PCs. The user binds the web server and the WSDL. This enables the web service to be used by correspondence
24、 using SOAP (Simple Object Access Protocol). The database server saves all information of the system such as food information, ordering information, client information. The cash register is responsible for cost calculation of the consumer. The mobile context server applies context to the contents by
25、 using styles, an attribute override, and templates according to the resources of a given mobile device. Desktop users can ask for services after checking the WSDL of the service from the web server. A desktop on a wired network can be used to browse full contents on one screen shot. When a user req
26、uests food information through a wired network, the web server serves the information by connecting to the database server. When a user requests food information through a wireless network, the mobile context server divides the context pages according to the screen size of the mobile device. It also
27、 filters the pages according to mobile devices and then browses the adopted content from the context server to the mobile web browser. The mobile context server reconfigures contents offered by the web server. Figure 1The System Architecture B. Web Service Security Model Web service security can be applied at three levels : Platform/transport-level (point-to-point) security； Application-level (customer) security； Message-level (end-to-end) security. Each approach has different strengths and weaknesses. The choice of the
