A Framework for Analyzing Mobile Transaction Models

Currently, mobile technology is undergoing a high growth stage, allowing an increasing plethora of mobile devices (handheld PCs, handsets, etc.) to access daily-distributed resources and information. This availability entails the requirement for transactional capabilities adapted to the specific characteristics of the mobile environment, without losing the consistency and reliability guarantees of traditional OLTP systems. This chapter surveys the definition and extension of transactional models to a mobile environment, starting with an explanation of this environment and a review of transactional systems applied to mobile computing. Afterwards, a framework for analyzing competing mobile models is defined. This framework allows for different constraints to be imposed on the most general “motion independence” requirement. Finally, existing mobile transaction proposals are assessed against the framework and classified, highlighting their relative strengths and weaknesses in different situations.

Software Agents for Mobile Commerce Services Support

This chapter considers an application of software agents to mobile commerce services provision. With the increasing number of e-commerce services for mobile devices, there are challenges in making these services more personalized and in taking into account the severely constrained bandwidth and restricted user interface these devices currently provide. In this chapter we present an agent-based platform for support of mobile commerce using wireless devices. Agents represent mobile device customers in the network by implementing highly personalized customer profiles. The platform allows customization and adaptation of mobile commerce services as well as pro-active processing and notification of important events. Information to the customers is delivered via both an access to the Internet and SMS messages. Usage of the platform is illustrated by examples of valued customer membership services and subscription services support. We hope that the presented work demonstrates benefits of software agents as assistants in mobile commerce services.

The Development of Ordered SQL Packages in Peer-to-Peer Data Warehousing Environments

This chapter discusses how the capabilities of database languages are enhanced to manipulate user-defined data orderings within the framework of the Ordered Relational Model (the ORM), which incorporates partial orderings into data domains. The motivation for applying the ORM in data warehousing environment is that business queries in an enterprise usually involve order. We have already defined and implemented Ordered SQL (OSQL), which allows users to capture the underlying semantics of the ordering of the data for a given application. Herein we demonstrate that OSQL aided with a package discipline can be an effective means to manage the inter-related operations and the underlying data domains of a wide range of advanced applications that are vital in data warehousing, such as temporal, incomplete, and fuzzy information. We also discuss the employment of OSQL system with three packages of OSQL_TIME, OSQL_INCOMP, and OSQL_FUZZY over a Peer-to-Peer network. Using our suggested framework, the data content of a data warehouse can be better adapted in a dynamic environment.

Applying UML for Designing Multidimensional Databases and OLAP Applications

Multidimensional (MD) modeling is the basis for Data warehouses (DW), multidimensional databases (MDB), and On-Line Analytical Processing (OLAP) applications. In this chapter, we present how the Unified Modeling Language (UML) can be successfully used to represent both structural and dynamic properties of these systems at the conceptual level. The structure of the system is specified by means of a UML class diagram that considers the main properties of MD modeling with minimal use of constraints and extensions of the UML. If the system to be modeled is too complex, thereby leading us to a considerable number of classes and relationships, we sketch out how to use the package grouping mechanism provided by the UML to simplify the final model. Furthermore, we provide a UML-compliant class notation (called cube class) to represent OLAP initial user requirements. We also describe how we can use the UML state and interaction diagrams to model the behavior of a data warehouse system. We believe that our innovative approach provides a theoretical foundation for simplifying the conceptual design of multidimensional systems, and our examples illustrate the use of our approach.

Methodology Evaluation Framework for Component-Based System Development

Components are already prominent in the implementation and deployment of advanced distributed information systems. Part and parcel of this development are the effective Component Based Development (CBD) methodology encompassing methods, tools, and techniques that effectively target the existing component based technology. Current CBD methodologies lack a comprehensive component based concept structure. They handle components mainly at the implementation and deployment phases still, which are heavily influenced by UML notations. In this paper, a presentation is made of an evaluation framework which highlights the extent to which a methodology is component-oriented. Current CBD methods and approaches do not provide full support for various component concepts. Therefore, a CBD method sample was evaluated using the framework’s concepts and requirements. CBD method improvements are proposed based on the evaluation. The improved approach suggests the use of the standard RM-ODP as an underlying framework, to provide consistent, systematic, and integrated CBD methodology engineering support throughout the lifecycle.

Towards Flexible Specification, Composition and Coordination of Workflow Activities

We introduce the ActivityFlow specification language for flexible specification, composition, and coordination of workflow activities. The most interesting features of the ActivityFlow specification language include (1) a collection of specification mechanisms allowing workflow designers to use a uniform workflow specification interface to describe different types (i.e., ad-hoc, administrative, or production) of workflows involved in their organizational processes (an objective of this feature is to help increase the flexibility of workflow processes in accommodating changes); (2) a set of activity modeling facilities, enabling workflow designers to describe the flow of work declaratively and incrementally, allowing reasoning about correctness and security of complex workflow activities independently from their underlying implementation mechanisms; (3) an open architecture that supports user interaction as well as collaboration of workflow systems of different organizations.

On the Representation of Temporal Dynamics

Research in temporal database management has suggested that the Entity-Relationship model must be extended to compensate for its lack of constructs for representing the world’s dynamic nature. This claimed deficiency arises from the mistaken idea that Entity-Relationship diagrams represent only a snapshot of reality. Practitioners have long used Entity-Relationship diagrams without temporal extensions to design systems with rich support for temporality by using entities to represent the events that cause state changes, rather than by defining temporal attributes and relationships to record past states. While both approaches can represent temporality, only the event approach maintains modeling parsimony and represents why a particular state exists.

A Review of Experiments on Natural Language Interfaces

This chapter provides a review, using both qualitative and quantitative approaches, of experimental studies on natural language interfaces. As data utilization is an important aspect of information systems, numerous experimental studies have been conducted on user performance involving database-related tasks with various database models and/or languages. We propose a two-dimensional conceptual framework aimed at classifying and systematically analyzing these studies, in order to provide a bigger picture facilitating systematic understanding of this body of research. The classification exercise shows that studies involving natural language interfaces did not have very consistent findings. Correspondingly, we applied the meta-analytic technique to attempt to gain insight into these differences.

Considering Mobility in Query Processing for Mobile Commerce Systems

With the merge of mobile computing and electronic commerce technologies, millions of mobile users in the near future could carry a mobile device requesting services through the electronic commerce applications. While serving such a mobile user, the server should consider how to minimize the response time of the request. This chapter discusses the issue of data processing for mobile commerce systems. Due to the characteristics of a mobile commerce environment such as user’s mobility, the user may not be at the same site as where he/she issued the request when the request’s result is ready to deliver to the user. This chapter argues that conventional strategies for query processing are no longer adequate in a mobile commerce environment and introduces some query processing strategies considering mobility for the mobile commerce systems. All the strategies are presented along with a cost analysis as the theoretical basis. Last, some of outstanding and interesting issues are described.

A Run-Time Based Technique to Optimize Queries in Distributed Internet Databases

An adaptive probe-based optimization technique is developed and demonstrated in the context of an Internet-based distributed database environment. More and more common are database systems, which are distributed across servers communicating via the Internet where a query at a given site might require data from remote sites. Optimizing the response time of such queries is a challenging task due to the unpredictability of server performance and network traffic at the time of data shipment; this may result in the selection of an expensive query plan using a static query optimizer. We constructed an experimental setup consisting of two servers running the same DBMS connected via the Internet. Concentrating on join queries, we demonstrate how a static query optimizer might choose an expensive plan by mistake. This is due to the lack of a priori knowledge of the run-time environment, inaccurate statistical assumptions in size estimation, and neglecting the cost of remote method invocation. These shortcomings are addressed collectively by proposing a probing mechanism. Furthermore, we extend our mechanism with an adaptive technique that detects sub-optimality of a plan during query execution and attempts to switch to the cheapest plan while avoiding redundant work and imposing little overhead. We demonstrate that this probe technique can be extended in a client-server environment as a basis for choosing the right place for the execution of user defined functions (UDFs). An implementation of our run-time optimization technique for queries was constructed in the Java language and incorporated into an experimental setup. The results demonstrate the superiority of our probe-based optimization over a static optimization.