18.1 Location-Based Services LBS include all applications that make use of location and geographic data. It is touted as the killer app for mobile commerce because it enables brand new applications not possible in the desktop world. There are several types of LBS applications: Pull-based applications: The user actively sends out her location information to a server and pulls in location information such as driving maps and nearby stores. Push-based applications: Service providers detect users in their proximity and push out services such as coupons and advertisements. A central issue in push-based applications is how to protect user privacy. Location information can be highly sensitive. It is extremely important vendors get information from and push services to only opt-in users. A combination of pull and push: For example, a user can first pull nearby coffee shop locations and make a mobile reservation. Then he can send meeting alerts to peers within certain distances from the shop. The peers will be able to accept or reject the invitation. Although LBS offers appealing business values, its implementation technologies are sophisticated. The core technology for any LBS solution is Geographic Information System (GIS), which performs important functions such as determining street addresses from…

  17.1 A Little History When the MIDP v1.0 specification was released in 2000, it was a good compromise between the small footprint required by small devices at that time and features necessary to support simple mobile applications. Since then, capabilities of mobile devices and sophistication levels of mobile clients have increased drastically. MIDP v1.0 is showing its limitations. One such limitation is the lack of support to access structured data. To address this problem, a major design goal for the MIDP v2.0 specification was to add a set of XML and Web Services XML. However, during the development of MIDP v2.0, the expert group could not agree on the exact format, features, and footprint of the XML API. Considering that a large portion of MIDP v2.0 devices will be used for gaming applications and may never consume Web Services, the MIDP v2.0 expert group decided that the XML API should be offered as a standard Optional Package for both CLDC-based and CDC-based profiles. The specification development is delegated to a new expert group in Java Specification Request 172 (JSR 172, "J2ME Web Services Specification"). The JSR 172 expert group consists of 30 industry-leading corporations and individuals. It includes all the…

16.1 What Is SOAP Web Services? Standardization is key to the success of XML. Raw XML by itself is just a bunch of tags, attributes, and text that can be used to express almost anything in any format. The flexibility gives XML the power of a universal data language. But in any specific application field, the meaning of XML syntax elements must be standardized to ensure interoperability. In order for XML to carry generic data between object-oriented programming systems, we need a syntax system that expresses complex object and type information in serialized XML format. 16.1.1 The SOAP Advantage SOAP is the most widely used protocol for XML-based object serialization. It is the technology of choice for future ubiquitous Web Services. Compared with competing technologies, SOAP has the following advantages: Strong type support: SOAP defines more than 40 standard data types through XML Schema and allows users to custom-define complex data types. Such sophisticated data-type support makes SOAP a powerful and rich language for exchanging information among today's widely deployed object-oriented systems. Flexible and ubiquitous messaging: In addition to strong data-type support, SOAP also supports various messaging schemes. Those schemes include synchronous RPC, asynchronous messaging, multicast messaging (subscription), and complex…