Abstract
During the last two decades a lot of methodology research has been conducted for the design of software user interfaces (Kirisci, Thoben 2009). Despite the numerous contributions in this area, comparatively few efforts have been dedicated to the advancement of methods for the design of context-aware mobile platforms, such as wearable computing systems. This chapter investigates the role of context, particularly in future industrial environments, and elaborates how context can be incorporated in a design method in order to support the design process of wearable computing systems. The chapter is initiated by an overview of basic research in the area of context-aware mobile computing. The aim is to identify the main context elements which have an impact upon the technical properties of a wearable computing system. Therefore, we describe a systematic and quantitative study of the advantages of context recognition, specifically task tracking, for a wearable maintenance assistance system. Based upon the experiences from this study, a context reference model is proposed, which can be considered supportive for the design of wearable computing systems in industrial settings, thus goes beyond existing context models, e.g. for context-aware mobile computing. The final part of this chapter discusses the benefits of applying model-based approaches during the early design stages of wearable computing systems. Existing design methods in the area of wearable computing are critically examined and their shortcomings highlighted. Based upon the context reference model, a design approach is proposed through the realization of a model-driven software tool which supports the design process of a wearable computing system while taking advantage of concise experience manifested in a well-defined context model.
TopIntroduction
The benefit of applying wearable computing systems in modern industrial environments has become evident, especially in environments with a high degree of service and maintenance operations. Such as the design of any software or computing system, a wearable computing system should be designed under consideration of its intended context of use. In recent studies it has been shown that wearable computing systems which were designed without incorporating knowledge of the context of use in the design process usually resulted in systems, unsuitable for supporting the user in his tasks. Internal studies of Airbus/EADS Research revealed this fact and were a driver for our research. A good example for an inappropriate design is a tablet-PC. Observations from our side revealed an interesting fact when carrying tablet-PC’s during performance of a mobile task. When used within a mobile task as a digital clipboard, female and male users tend to carry the device in different ways. While women hold the tablet-PC against their hips, men hold the device against their breasts. Children in general carry a tablet-PC in a similar way as female users. These examples indirectly highlight that the context of use was not fully considered during the design process. One reason may be that there is only minimal tool support in the early stages of the design process of mobile and wearable computing systems. Wearable computing systems are, from a technical point of view, even signed by exploiting context information of the real world, and are among other components defined by the presence of context-aware applications (Hinckley 2003). Regarding future industrial environments which tend to be very information-rich, it is likely that wearable computing systems will play a vital role in supporting the user during the performance in his tasks, thus in interacting with his working environment. Context is highly dynamic in these kinds of environments due to the versatility of assigned tasks which take place in several locations. It should be the aim that the user is unobtrusively supported by the wearable computing system during his primary task. As illustrated in Figure 1, the user is continuously interacting with the real world in fulfilling his primary task. At the same time the user is supported by the wearable computing system which seamlessly exchanges information with the real world. An interaction mode change, as it is the case with conventional mobile computing systems, where the user switches between interaction with the computing system and interaction with the real world, is reduced to the minimum.
Figure 1. Interaction of the user with real world when being supported by a wearable computing (WearIT@Work 2005)
In order to guarantee the most appropriate design of a wearable computing system, it is crucial that wearable computing systems are designed under consideration of the context of use. Hence, the challenge is to elaborate how context can be incorporated in a design technique in order to support the design process of wearable computing systems at an early stage.
Key Terms in this Chapter
Platform-Independent-Model (PIM): A conceptual design realizing the functional requirements of a technical system or infrastructure.
Primary Task: A primary task is defined as the real world task, which is the main one has to carry out.
Ubiquitous Computing: A post-desktop model of human-computer interaction in which information processing has been thoroughly integrated into everyday objects and activities.
Context Reference Model: An abstract representation of the aspects of a current situation, which fulfils the criteria of referability.
Context: In our research we define context as the aspects of a current situation.
Platform context: Type of context which is comprised of the aspects directly related to the characteristics and functionalities of a hardware platform.
Human context: Type of context which is comprised of the aspects directly related to the tasks, interactions, roles and preferences of the human user.
Platform-Specific-Model (PSM): A concrete design representation for a technical system or infrastructure realizing all non-functional, but technology-related requirements like scalability, reliability and performance.
Model-Based Approach: An approach which is based upon the usage of software models in order to develop or specify an application or platform.
Nasa TLX Method: Nasa Task Load Index is a widely accepted method for collecting person’s work load.
Wearable Computing System: An unobtrusive computing system consisting of components such as a computing device, an input device and an output device. Wearable computing systems are typically worn by human users on their body, integrated in clothing. These kind of computing systems have the purpose of providing context-sensitive support the user in the performance of his tasks.
Secondary context: Type of content which emerges from primary context and is sensed by a human user via an intermediary device. In our research we define secondary context as the type of context that has no direct impact upon the properties of a hardware platform, but may lead to an additional implication which has to be considered in the design process.
Context-Aware Computing: Context-aware computing is a mobile computing paradigm in which applications can discover and take advantage of contextual information.
Interaction Device: An interaction device is a mobile or stationary hardware component which enables the interaction between the human user and an application or the environment of the user. An interaction device can be an input device, an output device, or a device which incorporated both components for information input or output.
Primary context: Type of context that is immediate and directly experienced by a human user. In our research we define primary context directly impacts the physical properties of a hardware platform.
Model-Driven Architecture (MDA): A concept which aims to produce source code from abstract, human-elaborated models, e.g. modeling diagrams like class diagrams. The main goal of MDA is to separate the design process form the technical architecture itself.
Future industrial environment: Industrial environments are characterized by the presence of ubiquitous computing technologies.
Environmental context: Type of context which is comprised of the aspects directly related to the infrastructure, physical properties, and restrictions regarding the environment.
Wizard-of-Oz Method: The Wizard of Oz Method is a research experiment in which subjects interact with a computer system that subjects believe to be autonomous, but which is actually being operated or partially operated by an unseen human being.