Editorial: smart buildings

In the old days, ‘buildings’ provide a sense of security to safeguard the human life and properties from dangers. The research endeavours focused on structural designs and construction methods to prevent buildings from being damaged or collapsing. Nowadays people are not only satisfied with the sense of security, but also the quality of life a vital cornerstone of sustainability. The researchers are therefore focusing on equipping ‘smart’ capabilities so enabling ‘intelligent buildings’ to be planned, designed, constructed, and maintained with the aim of improving and upgrading human life in terms of health and wellbeing. In recent years, the development of ‘smart enablers for intelliegent buildings’ pushed by both the academia and practitioners worldwide in the building and construction sectors can be observed, due to the advancement of technologies such as sensing technologies. On 17–21 June 2019, the Conseil International du Bâtiment (CIB) World Building Congress 2019 (WBC 2019) on Constructing Smart Cities took place in The Hong Kong Polytechnic University with the host being the Department of Building and Real Estate. This triennial international congress facilitated the in-depth exchange of research ideas on various aspects of Smart Intelligent Cities including planning, design, construction, operation, and maintenance, and fostered the close collaboration between academia and practitioners. During the CIB WBC 2019, particularly, the CIB Working Commission Group W098 chaired by ProfessorDerekClements-Croome andDrTongYang, fruitful, constructive, and inspiring discussions about intelligent buildings for people were launched and highlighted for implementation. In general, the related topicswere centred onenergyand environmental performancesof smart buildings byapplying sensing devices and information platforms. The reported research works can be found with reference to the established CIB themes of intelligent buildings and infrastructures, smart planning, design and construction, smart services all contributing to intelligent and responsive buildings. Built upon the research works presented in the CIB WBC 2019, outstanding conference papers were selected and invited for enriching the contents which were accepted for publication after rigorous peer review in this special issue of ‘Intelligent Buildings International’ which aims to increase the awareness of intelligent and smart city development. Highlights of each paper is provided below for readers’ reference. Paper 1: Maintenance service optimization in smart buildings through ultrasonic sensors network The opening paper presented by Moretti et al. (2020) proposed a smart building maintenance strategy using ultrasonic sensors. This research study used ultrasonic sensors for detecting and monitoring the occupancy in buildings. Once the occupancy data are analysed with reference to the pre-defined threshold, the require-maintenance alert will be triggered automatically. The feasibility of the proposed smart system was proved and validated by a real-world case study in Italy. Discussions were given to the sensors’ cost and level of precision. This innovation enhances the cost-effectiveness of facility maintenance management service towards smart buildings. Paper 2: Bayesian updates for indoor environmental quality (IEQ) acceptance model for residential buildings The second paper written by Tsang et al. (2020) developed an indoor environmental quality acceptance model for smart residential buildings based on the Bayesian updating technique. Bayesian approach was innovatively used to update the objective indoor environmental quality model driven by the subjective indoor environmental quality responses. Notably, those responses are