Visual languages and quality evaluation in multichannel adaptive information systems

Abstract

Multichannel Adaptive Information Systems (ISs) are becoming the new paradigm for building complex interorganization ISs based on the use of different devices, Web services, and XML specifications. Modeling Multichannel Adaptive ISs requires complex interactions between the users and the system front-end due to the different capabilities of existing devices. Unfortunately, the expressive power and effectiveness of visual languages have not been fully exploited in this new area. In this paper we address two related issues. First we propose a visual language that allows for adapting the presentation layer to different physical devices; then we describe a technique to evaluate possible tradeoffs between usability and other qualities of service in Web services design.

Introduction

In the 1980 and 1990 an impressive amount of research has been performed in the field of Visual Languages (VL). In particular a number of visual query systems have been proposed [1] for querying databases using a visual representation to depict the domain of interest and express related requests.

Recently, Multichannel Adaptive Information Systems (ISs) [2] are becoming the new paradigm for building complex interorganization ISs based on the use of different devices, Web services, and XML specifications. Modeling Multichannel Adaptive ISs requires complex interactions between the designer and the system due to the different capabilities of existing devices. Moreover, the verbosity of XML documents makes difficult to understand the back-office layer realized by Web services and the service oriented architecture (SOA) model [3]. As a consequence, a new generation of visual tools is needed for describing both the interaction of Multichannel Adaptive ISs with the end user and the back-office processes. Concerning the first issue, a number of proposals have been presented in the field of Web applications [4], [5] suffering the lack of visual tools supporting the context adaptability. Concerning the SOA model, existing tools are based on UML activity diagrams [6], statecharts [7], or visual languages defined ad hoc, such as the case of BPMN [8]. In these proposals poor attention is placed in the representation of the quality of service (QoS) provided by business processes. More in general, in existing visual tools, usability is the only QoS considered, while in Multichannel Adaptive ISs other QoS dimensions are relevant, such as performance, security, and data quality. In the design of Web services, a number of design choices are influenced by QoS, that may request a balancing among conflicting acceptable levels of different qualities.

In this paper we address some issues arising in the area of visual languages and their role in QoS evaluation in Multichannel Adaptive ISs. We first describe a visual tool that allows for adapting the presentation layer to different physical devices, addressing the usability issue. The second contribution concerns a technique for QoS evaluation in Web service design, that identifies possible tradeoffs among usability and other QoS dimensions. The paper is organized as follows: in Section 2 the proposed visual language is presented; Section 3 describes the QoS evaluation technique; Section 4 presents related works and Section 5 draws conclusions and future works.