The digitization and automation of contracts within the built environment through blockchain has demonstrated potential. Nonetheless, the use of on-chain smart contracts can amount to substantial costs. This study proposes a blockchain-governed approach to individually assess whether and how to use blockchain for different components of contracts. We explain the rationale behind the concept and implement a pilot prototype of a performance-based, blockchain-governed contract. The results promise an alternative and more cost-effective approach to smart or intelligent contracts in the built environment, while still allowing for trusted verification of key contract parts through blockchain.@en

The analysis of network structure is essential to many scientific areas ranging from biology to sociology. As the computational task of clustering these networks into partitions, i.e., solving the community detection problem, is generally NP-hard, heuristic solutions are indispensable. The exploration of expedient heuristics has led to the development of particularly promising approaches in the emerging technology of quantum computing. Motivated by the substantial hardware demands for all established quantum community detection approaches, we introduce a novel QUBO-based approach that only needs number-of-nodes qubits and is represented by a QUBO matrix as sparse as the input graph’s adjacency matrix. The substantial improvement in the sparsity of the QUBO matrix, which is typically very dense in related work, is achieved through the novel concept of separation nodes. Instead of assigning every node to a community directly, this approach relies on the identification of a separation-node set, which, upon its removal from the graph, yields a set of connected components, representing the core components of the communities. Employing a greedy heuristic to assign the nodes from the separation-node sets to the identified community cores, subsequent experimental results yield a proof of concept by achieving an up to 95% optimal solution quality on three established real-world benchmark datasets. This work hence displays a promising approach to NISQ-ready quantum community detection, catalyzing the application of quantum computers for the network structure analysis of large-scale, real-world problem instances.

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Long-term access to lifecycle data is key to a successful transition towards a circular built environment. However, the underlying technology often remains centralized and risks becoming inaccessible over time. In this paper, we investigate whether decentralized access methods using Web3, i.e. blockchain and decentralized data storage protocols, can help to mitigate this limitation. We implement Web3 data access mechanisms for a material passport with both a role-based and a token-based smart contract. Initial results suggest that Web3 offers a promising approach to data access over the lifecycle of a built asset-but only with careful design choices.

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A library of prefabricated parts and assemblies, i.e. module library, can help a firm in the construction industry transition to a more industrialized and product-oriented approach. However, existing approaches to manage such libraries are oriented around single-use projects. There is need for a more flexible data structure to support storage, analysis and reuse of design information. This paper proposes a graph-based approach to develop a module library. The approach includes a graph representation of modules, a graph database development, and a graph-based similarity analysis. The proposed approach is validated using a prefabricated timber panel system via a web-based application. Implementation demonstrates a more efficient process for bill of material generation and identifying the impacts of design changes.

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One emerging strategy in industrialized construction is the use of mass customization to increase product efficiency without sacrificing design flexibility. Effective implementation of mass customization can be done through a product platform, i.e. a configurator. However, existing configurators often lack integration of knowledge from the downstream supply chain such as manufacturing. This paper proposes a conceptual framework for a configurator unified through a manufacturing kit-of-parts. Kit-of-parts are pre-engineered and pre-designed digital models representing fabrication-ready components. Using production rules and restraints, accurate planning and design representations can be derived and utilized in the configurator. This research develops a configurator prototype using three-tier architecture. The prototype supports a low-to-high level of detail of kit-of-parts. It integrates product platforms and project development across multiple building phases including site planning, floor plan layout, and 3D model generation. Finally, the implementation of a modular building configurator illustrates the benefits of the proposed configurator-based workflow.@en