Abstract
In IEEE 802.11 based wireless networks interference increases as more access points are added. A metric helping to quantize this interference seems to be of high interest. In this paper we study the relationship between the improved attacking case metric, which captures interference, and throughput for IEEE 802.11 based network using directional antenna. The y(1/3) = a + b (ln x)(3) model was found to best represent the relationship between the interference metric and the network throughput. We use this model to predict the performance of similar networks and decide the best configuration a network operator could use for planning his network.

Abstract
Retailers need demand forecasts at different levels of aggregation in order to support a variety of decisions along the supply chain. To ensure aligned decision-making across the hierarchy, it is essential that forecasts at the most disaggregated level add up to forecasts at the aggregate levels above. It is not clear if these aggregate forecasts should be generated independently or by using an hierarchical forecasting method that ensures coherent decision-making at the different levels but does not guarantee, at least, the same accuracy. To give guidelines on this issue, our empirical study investigates the relative performance of independent and reconciled forecasting approaches, using real data from a Portuguese retailer. We consider two alternative forecasting model families for generating the base forecasts; namely, state space models and ARIMA. Appropriate models from both families are chosen for each time-series by minimising the bias-corrected Akaike information criteria. The results show significant improvements in forecast accuracy, providing valuable information to support management decisions. It is clear that reconciled forecasts using the Minimum Trace Shrinkage estimator (MinT-Shrink) generally improve on the accuracy of the ARIMA base forecasts for all levels and for the complete hierarchy, across all forecast horizons. The accuracy gains generally increase with the horizon, varying between 1.7% and 3.7% for the complete hierarchy. It is also evident that the gains in forecast accuracy are more substantial at the higher levels of aggregation, which means that the information about the individual dynamics of the series, which was lost due to aggregation, is brought back again from the lower levels of aggregation to the higher levels by the reconciliation process, substantially improving the forecast accuracy over the base forecasts.

Abstract
Healthcare is facing complex challenges that demand profound service system innovation. Service design offers an opportunity to move beyond explanatory research and take an action-oriented approach that combines research rigor with relevance to foster innovation in healthcare. We present three research projects that illustrate different ways service design can enable health service system innovation to create uplifting changes in wellbeing. The first research project utilizes a decision-making approach to support design teams in developing value co-creating technology-enabled services for skin cancer prevention. The second project employs a sense-making approach through participatory design to develop a National Electronic Health Record that addresses the multiple and conflicting goals of healthcare network actors. The third project uses an institutional change approach to develop a new digital service for youth with mental health issues while simultaneously shifting the culture of the clinic toward people-centered care through participatory service design. We conclude with research directions to leverage the potential of service design for healthcare innovation, including strengthening the dialogue between explanatory and design research, exploring new multidisciplinary collaborations and integrating multiple research methods.

Abstract
Background: Health Information Systems (HIS), and especially Electronic Health Records (EHR), offer great promise. However, the true benefits of HIS and EHR are more elusive as research shows they have obtained mixed results across countries. To increase the success of these systems while creating value for healthcare professionals, research emphasizes the importance of involving clinical users in the design of HIS. Objective: Following calls for interdisciplinary research and increased end-user participation in HIS development, this paper shows how a service design approach can support the successful development and implementation of national EHRs. Service design brings a human-centered, participatory, holistic, creative and visual approach to HIS development, through an iterative process of exploration, ideation, reflection and implementation, fostering stakeholder participation and co-creation of the solution. Method: This paper presents an in-depth case study of the Portuguese National EHR development and implementation following a service design approach. The study involved individual and group interviews, as well as participatory design workshops with more than 170 participants along the different stages of exploration, ideation, reflection and implementation. Results: The service design approach, including the visual models and tools used across the different design stages, was instrumental to envision new EHR concepts and design the system to enhance healthcare users experience. A qualitative study performed after implementation showed that the EHR was considered useful and easy to use, and these results are backed by widespread usage of the system. Discussion and conclusion: This paper shows how a service design approach can address key challenges in EHR development. By adopting a holistic perspective, service design broadens the scope of EHR development to understand its broader service system and position it to enable value creation with users. The human-centered, participatory, creative, visual and holistic approach supports the understanding of user needs and context, and their active involvement in the design and co-creation effort. This service design approach fosters user adoption at the implementation stage. Service design can thus contribute to the successful development and implementation of EHRs.

Abstract
Purpose Service design is a multidisciplinary approach that plays a key role in fostering service innovation. However, the lack of a comprehensive understanding of its multiple perspectives hampers this potential to be realized. Through an activity theory lens, the purpose of this paper is to examine core areas that inform service design, identifying shared concerns and complementary contributions. Design/methodology/approach The study involved a literature review in two stages, followed by a qualitative study based on selected focus groups. The first literature review identified core areas that contribute to service design. Based on this identification, the second literature review examined 135 references suggested by 13 world-leading researchers in this field. These references were qualitatively analyzed using the NVivo software. Results were validated and complemented by six multidisciplinary focus groups with service research centers in five countries. Findings Six core areas were identified and characterized as contributing to service design: service research, design, marketing, operations management, information systems and interaction design. Data analysis shows the various goals, objects, approaches and outcomes that multidisciplinary perspectives bring to service design, supporting them to enable service innovation. Practical implications - This paper supports service design teams to better communicate and collaborate by providing an in-depth understanding of the multiple contributions they can integrate to create the conditions for new service. Originality/value This paper identifies and examines the core areas that inform service design, their shared concerns, complementarities and how they contribute to foster new forms of value co-creation, building a common ground to advance this approach and leverage its impact on service innovation.

Abstract
Purpose Service design is a multidisciplinary approach that is key to service innovation, as it brings new service ideas to life. In this context, the development of new service design methods and models for creating new service futures is an important stream of service design research. Such developments can benefit from a systematized research methodology that builds on existing knowledge and robustly evaluates the suitability of research contributions. To address this challenge, the purpose of this paper is to present design science research (DSR), an established methodology from the information systems field, and examine how it can be useful for service design research by supporting the development of new artifacts, such as service design constructs, methods and models. Design/methodology/approach This paper presents DSR and related literature and shows how DSR can support service design research through a step-by-step approach. A methodology to develop prescriptive-driven solutions for classes of problems, DSR can support service design research in developing rigorous and relevant research. One illustrative example of a service design research effort using the DSR approach is presented. Findings Building on DSR's robust methodological background, this paper discusses how DSR can support service design research, namely, through the development of new methods and models, and how DSR can be adapted to leverage service design research participatory, iterative, human-centric and creative approach. Originality/value This paper provides an overview of DSR and proposes it as a methodology to conduct service design research, offering step-by-step guidance on the application of DSR in service design research and discussing how it can be adapted according to the specific characteristics of service design research and drive future research.