Architectural support for dynamic homecare service provisioning

Abstract

Providing IT-based care support for elderly people at home (i.e., carereceivers) is proposed as a highly promising approach to address the aging population problem. With the emergence of homecare application service providers, a homecare system can be seen as a set of linked services. Configuring and composing existing homecare application services to create new homecare composite applications can reduce the application development cost. The idea even looks more promising if the service provisioning is dynamic, i.e., if applications can update their behaviours with respect to the contextual changes without or with minimum manpower. Dynamic service provisioning can play an important role to accept homecare systems in practical settings. This thesis proposes a Dynamic Homecare Service Provisioning (DHSP) platform to address the homecare contextual changes in an effective and efficient manner. An dynamic service provisioning, a composite application can be reconfigured. This can happen automatically on-the-fly (called adaptive service composition), by endusers for example nurses (which we call tailorable service composition) or by a programmer (which we call evolvable service composition). The proposed DHSP platform provides adaptive, tailorable and evolvable service provisioning in the homecare domain. To support this, a hybrid service composition approach has been proposed, in which the core of the application logic, which is rather stable, is specified in terms of processes, while rules are employed to specify the conditions and constraints to adapt the application behaviour. The rules are then exposed as a decision service, which can be employed by the process to make adaptation decisions with respect to runtime circumstances. As a proof of concept, we have developed a software prototype of our platform. The prototype was subsequently used in a real-world field test, which consists of two experiments, at a care institution in the Netherlands to validate the approach. The validation included both objective and subjective measurements. Being able to combine objective and subjective measurements, would be useful to know which level of effectiveness and efficiency is acceptable in the homecare domain. Moreover, we identified explanations of our observations that allowed us to understand which parts of our approach need further improvement. During the field test, the DHSP platform was used daily with more than 400,000 transactions in total over four months among the infrastructure and application services. The goal of the field test was to study the usability of the DHSP platform to address the homecare contextual changes in terms of (a) eectiveness, (b) eciency, and (c) satisfaction, both subjectively and objectively. In the first experiment of our field test, we found out that although the application services as actually delivered by the service providers met the users’ requirements, there were architectural mismatches across service providers due to unstated assumptions. Thus we introduced an Assumption-based Risk identification Method (ARM). The ARM method helped us identify several risks before using the DHSP platform in the second experiment of our field test. During the field test, we observed that the adaptivity of the homecare applications met the end-users’ (care-receivers and nurses) expectations, at least in the second experiment. The tailorability of the homecare applications also met the nurses’ expectations except for one specific type of homecare application. The nurses were satisfied with the fact that they only needed to use the same tailoring application for all the homecare applications. We also observed that the evolvability of the homecare applications met the programmers’ expectations. This was possible mainly because of using the decision service. Our field test showed that using the decision service improves the evolvability while its cost in terms of time and data communication is rather small. Our conclusion from the field test is that the DHSP platform is suitable for homecare service provisioning. However, we only evaluated the proposed DHSP platform with a limited number of participants (care-receivers, care-givers, IT specialist) in one care center in the Netherlands in which care-receivers live in their care homes. Evaluation of the platform in other situations (e.g., a situation where care-receivers live at their own homes and receive support remotely) may have different results. Moreover, the platform should be evaluated using other homecare applications and their required application services.