After a decade of periodic truss-, plate-, and shell-based architectures having dominated the design of metamaterials, we introduce the non-periodic class of spinodoid topologies. Inspired by natural self-assembly processes, spinodoid metamaterials are a close approximation of microstructures observed during spinodal phase separation. Their theoretical parametrization is so intriguingly simple that one can bypass costly phase-field simulations and obtain a rich and seamlessly tunable property space. Counter-intuitively, breaking with the periodicity of classical metamaterials is the enabling factor to the large property space and the ability to introduce seamless functional grading. We introduce an efficient and robust machine learning technique for the inverse design of (meta-)materials which, when applied to spinodoid topologies, enables us to generate uniform and functionally graded cellular mechanical metamaterials with tailored direction-dependent (anisotropic) stiffness and density. We specifically present biomimetic artificial bone architectures that not only reproduce the properties of trabecular bone accurately but also even geometrically resemble natural bone.

Both private and public sector organizations tend to participate in networks in order to gain access to knowledge, skills and resources of other organizations and to create synergies to achieve highly demanding and complex goals they cannot attain individually. The governance of these networks has been recognized as being an important variable influencing organizational network performance. This Special Issue aims to contribute to the investigation and understanding of the relationships between ICT and governance of organizational networks. This introductory paper provides the conceptual and theoretical background. The relationship between network governance and technology is bi-directional; evolutions in ICT enable the development of new types of network collaborations and governance, whereas governance of collaboration networks is critical for the development of complex ICT infrastructures. We argue that network governance should be conceptualized as an evolving socio-technical process shaped by actors and aimed at tackling complex and dynamic contemporary challenges.