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Introduction. Intracranial aneurysms with a radiological sign of a donut are a medical priority and have been described in a small number of cases. This radiological sign occurs in aneurysms in which there is partial thrombosis inside aneurismal sac and circular laminar flow between the aneurismal wall and the thrombus in its center. Consequently, there is a central contrast-filling defect of the aneurysm sac observed on different angiographic imaging methods. Case outline. We present a 35-year-old female patient admitted for examination due to frequent headaches, visual disturbances on the left and loss of sight on the right eye. Digital subtraction angiography (DSA) showed an aneurysm on the right internal carotid artery measuring 25.6 ? 25 mm, while neck measured 11 mm and included part of the C6 and C7 segments. Treatment decision was made that placing a flow-diverting stent across the aneurysm neck would be most beneficial in this case. After the procedure, the patient was discharged in the same general condition as she was before admission to the hospital. Seven months after the intervention, she reported for her first DSA control examination. Normal position of the left A1 segment was demonstrated, suggesting shrinkage of the aneurysm sac. An improvement of vision on both eyes was stated. Conclusion. We present a patient with a ?donut? aneurysm on the internal carotid artery, successfully treated with a flow-diverting stent.

The viability of novel network-level circular business models (CBMs) is debated heavily. Many companies are hesitant to implement CBMs in their daily practice, because of the various roles, stakes and opinions and the resulting uncertainties. Testing novel CBMs prior to implementation is needed. Some scholars have used digital simulation models to test elements of business models, but this this has not yet been done systematically for CBMs. To address this knowledge gap, this paper presents a systematic iterative method to explore and improve CBMs prior to actual implementation by means of agent-based modelling and simulation. An agent-based model (ABM) was co-created with case study participants in three Industrial Symbiosis networks. The ABM was used to simulate and explore the viability effects of two CBMs in different scenarios. The simulation results show which CBM in combination with which scenario led to the highest network survival rate and highest value captured. In addition, we were able to explore the influence of design options and establish a design that is correlated to the highest CBM viability. Based on these findings, concrete proposals were made to further improve the CBM design, from company level to network level. This study thus contributes to the development of systematic CBM experimentation methods. The novel approach provided in this work shows that agent-based modelling and simulation is a powerful method to study and improve circular business models prior to implementation.

Fast growth of cities decreases the quality of life in these places. In response, Municipalities install policies aiming to improve local livability. While literature suggests social structures to have a defining impact on policy effectiveness, current evaluation metrics are not able to take this into account. This paper presents the Social Neighbourhood model, an agent-based model used to simulate and explore how livability changes in a neighbourhood given various social structures and policies. The model is applied to a neighbourhood in The Hague, Netherlands. The main result of the modelling experiments is that social structures have a very strong influence on whether or not a policy to improve livability is effective. Three hypotheses, concerning this relationship between social structures, livability, and policy interventions are drawn up as a starting point for future research.

Cities consume almost 80 percent of world’s energy and account for 60 percent of all the emissions of carbon dioxide and significant amounts of other greenhouse gases (GHG). The ongoing rapid urbanization will further increase GHG emissions of cities. The quantification of the environmental impact generated in cities is an important step to curb the impact. In fact, quantifying the consumption activities taking place inside a city, if differentiated by socioeconomic and demographic groups, can provide important insights for sustainable-consumption policies. However, the lack of high-resolution data related to these activities makes it difficult to quantify urban GHG emissions (as well as other impacts). This paper presents a methodology that can quantify the carbon footprint of households in cities using consumption data from a national or European level, where the resource consumption is linked to socioeconomic attributes of a population. The methodology is applied to analyzing the environmental impact by household resource consumption in the city of The Hague in the Netherlands. The key insights reveal potential intervention areas regarding resource consumption categories and demographic groups that can be targeted to reduce GHG emissions due to consumption-driven activities in the city.

Published online: 14 February 2021 This paper investigates whether EU or national law provides legal authority to impose a direct or indirect obligation on Standard Essential Patent (“SEP”) holders to license at all levels of the value chain, including at component level (“license to all”, hereafter LTA). It concludes that neither patent law, competition law nor general principles of EU law impose an obligation on SEP owners to license at all levels of the production chain. Whether there exists an LTA obligation is primarily a matter of contract law and depends on the precise text of the FRAND commitment made to the relevant Standard-Setting Organisation (SSO). The ETSI FRAND commitment, which is of special relevance in the European context and is governed by French law, does not impose an LTA regime. With the exception of IEEE, other SSOs also do not seem to impose a contractual duty to license to all levels of the production chain. However, what EU law and FRAND commitments do require is access to the standard. Such access can be achieved in different ways: by having a direct license; by selling standard-implementing components to licensed end-device manufacturers (indirect license); by concluding non-assertion agreements; or even without any license or authorization at all if the SEP owner has a policy of monetising its SEPs only at one level of the production chain and does not enforce its patents against others.

Finding leverage points for sustainability transformation of industrial and infrastructure systems is challenging, given that transformation is emergent from the complex interactions among socio-technical system elements over time within a specific social, technical and geographical context. Participatory multi-modelling, in which modellers and stakeholders collaborate to develop multiple interacting models to support a shared understanding of systems, is a promising approach to support sustainability transformations. Theparticipatory processof modeling can serve as a leverage point by facilitating social learning amongst stakeholders, in which models can function as boundary objects that facilitate dialogue between stakeholders from different social worlds. We propose that participatory multi-modeling allows for the creation ofa boundary object ecology, which involves a set of interacting and co-evolving boundary objects emerging throughout the modeling process. To explore this, we analyse the participatory multi-modelling process in the Windmaster project in the Rotterdam Port industrial cluster to understand which design choices were key to the creation of boundary objects. Our analysis shows that two types of design choices were key: design choices that enabled translations between participants, and those between participants and their organisation. We conclude that conceptualising participatory multi-modelling as a process of an evolving boundary object ecology, creating and adaptingmultipleinteracting boundary objects provides a novel perspective that is useful for analysis and design of future participatory multi-modeling processes.

Flood adaptation measures implemented at household-level play an important role in reducing communities’ vulnerability. The aim of this study is to enhance the current modelling practices of human-flood interaction to draw new insights for FRM policy design. The paper presents a coupled agent-based and flood model for the case of Hamburg, Germany to explore how individual adaptation behaviour is influenced by flood events scenarios, economic incentives, and shared and individual strategies. Simulation results show that a unique trajectory of adaptation measures and flood damages emerge from different flood event series. Another finding is that providing subsidies increases the number of coping households in the long run. Households’ social network also has a strong influence on their coping behaviour. The paper also highlights the role of simple measures such as adapted furnishing, which do not incur any monetary cost, in reducing households vulnerability and preventing millions of euros of contents damage. Generally, we demonstrate that coupled agent-based and flood models can potentially be used as decision support tools to examine the role of household adaptation measures in flood risk management. Although the findings of the paper are case-specific, the improved modelling approach shows the potential to be applied in testing policy levers and strategies considering heterogeneous individual behaviours.

Patent pools collect patents from multiple patentees and license them out as a package. They offer one-stop-shop licensing efficiencies, reduce transaction costs, and increase the predictability of the licensing environment for the benefit of innovation diffusion. However, pools failed to take off for previous cellular standards. This article analyses both retrospectively the reasons for such failures and prospectively what makes the 5G environment more conductive to pool formation and licensing. Avanci, a patent pool for licensing cellular standards in the Internet of Things (IoT), is a significant development but has limited licensing coverage so far. The article then recommends five policy principles to facilitate pool licensing in the IoT. They include recognising that only enough upstream SEP owners need to join the 5G pool to create a market signalling effect. Some vertically integrated SEP owners may remain outsiders, and some bilateral licensing may co-exist without damaging the pool’s success. To encourage upstream SEP owners to join the pool, they should be allowed to set ‘high enough’ royalty rates and divide pools’ royalties among members under value proportionality rules. 5G pools must also be flexible and adopt different licensing programs that consider the specificities of each IoT market. Finally, pool administrators should consult with IoT implementers before establishing licensing programs for them and have infringement legal standing if everything else fails. These principles would go a long way in spurring the broader use of 5G pool licensing for a more efficient, straightforward, and predict- able IoT licensing environment.

Change in consumer behavior that leads to increased waste separation and recycling has been identified as a critical component of Chinese national strategy for constructing a “Circular Economy”. Various innovative solutions at community level targeting consumer behaviors are emerging in Chinese cities, using information technology that can track the volume and quality of the sorting process. In order to evaluate the potential impact of these novel solutions, we studied the behavioral change of households by initiating an experimental recycling program in a residential community in Beijing, and developed an Agent Based Model based on Theory of Planned Behavior (TPB) to identify key factors in changing behavior. The results show that the Social Norm (SN) has a decisive effect on whether an area starts recycling or not. As to the effectiveness of intervention, the Perceived Behavioral Control (PBC) plays a large role in the determination of the recycling behavior in this study, while the role of attitude is relatively small. The model outcomes can be corroborated with observations in different communities using similar technical solutions. In conclusion, we suggest that efficient local interactions among various stakeholders are needed in forming the social norm and common space that favorite recycling activities at the community level.

As energy systems grow more complex, modeling efforts spanning multiple scales, disciplines and perspectives are essential. Improved methods are needed to guide the development of not just individual models, but also multi-model ecologies – systems of interacting models. Currently there is a lack of knowledge concerning how multi-model ecologies can and should be designed to facilitate adequate understanding of energy system complexity and its consequences. Via an analysis of twelve multi-model initiatives both within and outside the energy domain, this paper elucidates possible design patterns and development paths for multi-model ecologies. The results highlight two broad paths to developing energy system multi-model ecologies, one prioritizing interoperability and the other prioritizing diversity. The former path facilitates the efficient development of models spanning multiple scales and (to a degree) disciplines, and can ease systematic testing of assumptions. The latter is suited to bridging traditional disciplines and perspectives and advancing knowledge within the interstices of different knowledge communities. It is furthermore suggested that a combination of diversity, connectivity and hierarchy in multi-model ecology composition is central to enabling the development of complex webs of models capable of addressing the complexity of real-world energy systems.

To lower the emissions of deep sea shipping, policymakers aim to decrease the use of heavy fuel oil (HFO) as a maritime fuel. Multiple alternatives for HFO exist, but despite new regulations, their use is still limited. To stimulate shipping companies to replace HFO by one of the alternatives, policymakers can use a variety of policy instruments. In this paper, we present a comprehensive system perspective of the maritime fuel system and agent-based model (MarPEM) that can be used to study the effects of policy instruments on the transition away from HFO. In contrast to existing studies on reducing maritime emissions, our system perspective captures the relations and dynamics between different components of the maritime fuel system. Thereby, it can account for the feedback and non-linear dynamics in the system. We illustrate the use of MarPEM to assess the effect of three policy instruments that each influence the maritime fuel system differently. The outcomes of the experiments are in line with previous studies and the opinion of industrial experts. The model is thus a valid representation of the maritime fuel system. By presenting a sufficiently detailed representation of the marine fuel socio-technical system, listing clear and detailed assumptions, and publishing the source code, future studies can use this work as basis to study the effects of other policy instruments. Thereby, this research enables future detailed studies of the maritime fuel system’s transition.