http://hdl.handle.net/10453/35195 2026-06-10T01:14:25Z http://hdl.handle.net/10453/195100 Title: An Empirical Study of Contractors’ Bidding Trends in Recurrent Bidding: A Case of Singapore Public Sector Construction Projects Authors: Zhang, Y; Oo, BL; Runeson, G; Lim, BTH Abstract: There have been limited empirical studies that aimed to establish the tenability of the stationarity assumption in recurrent construction bidding, and thus the need for and importance of allowing for continuity in bidding models remain unexplored. This study examined the bidding trends of individual contractors according to their level of experience in recurrent bidding, to test the tenability of the stationarity assumption. The data sample was a past bidding dataset of Singapore public sector construction projects over a five-year period between 2017 and 2021, with over 8000 bidding records from more than 900 contractors. The results show that there were statistically significant changes in the contractors’ bidding trends, irrespective of their level of experience in recurrent bidding and different time periodicities, ranging between 10 and 20 months. Thus, the stationarity assumption that contractors behave in a probabilistically consistent way over time, regardless of changing conditions, was untenable for the data sample involved. The observed changes in the contractors’ bidding trends cannot be regarded as random, but represent a continuous strategic process in response to changes in market forces. It is postulated that the possible causes of changes vary among individual contractors, in which there are a set of varying internal and external factors they consider at the time of bidding. The findings have implications for future bidding modelling attempts, in allowing for continuity in recurrent bidding. Contractors should systematically review and re-optimize their bidding strategy by leveraging their historical bidding data and bidding feedback information from clients, since their potential competitors will do the same thing for recurrent bidding. 2025-02-01T00:00:00Z http://hdl.handle.net/10453/193744 Title: RHpT: Bioclimatic framework for passive climate-adaptive bio-façades in urban contexts Authors: Debnath, KB; Pynirtzi, N; Scott, J; Davie, C; Bridgens, B 2026-05-01T00:00:00Z http://hdl.handle.net/10453/193581 Title: Let's Play: Co-designing inclusive school playgrounds with neurodivergent children Authors: Kelly, S; Kerr, J; Rieger, J; Cushing, DF Abstract: School playground design does not always reflect the needs of the children who play there, particularly neurodivergent children. This leads to exclusion and limited opportunities for skill development and peer relationships. This research engages children with neurodivergent conditions, who are rarely asked for their opinions, to conceptualise their vision of their ideal school playground. It demonstrates what is required in play environments to make them inclusive and why neurodivergent children should be included in research. This qualitative research involved two groups of children aged 10–12. Seven ‘predominantly neurodivergent’ (ND) students and six ‘predominantly neurotypical’ (NT) students, across two public, government-run schools in Brisbane, Australia. Play-based workshops used a co-design methodology to create play prototypes, drawings and journals, alongside interactions with a sensory sculpture on the school playground. Guided by the social model of disability and a strengths-based neurodivergent approach, thematic analysis revealed what play features were necessary to support more inclusive play. Participants developed four key design principles from play features that included sensory, social, challenge and nature as priority areas for inclusive playground design. Further, Biophilic, Salutogenic and Prospect-Refuge theories validate what play features are essential to sustain ND children's involvement at play. These elements fostered physical, social, and emotional inclusion, enabling children to play for longer, promoting positive social outcomes. Affordance theory underscores the value of these features in meeting neurodivergent children's needs and enhancing their play experiences. This research highlights opportunities for more inclusive playgrounds and for designers to create environments that support diverse users. 2025-12-01T00:00:00Z http://hdl.handle.net/10453/193474 Title: Dual-stage collaborative optimal allocation of cooling source in ice storage air-conditioning systems considering daily and emergency demand response Authors: Yan, X; Men, Q; Meng, Q; Debnath, KB Abstract: With the increasing pressure on the power grid from peak loads, demand response (DR) has become an important means to alleviate the power supply–demand imbalance and support carbon neutrality goals. In this context, ice storage air-conditioning (IAC) systems, as a key component of DR technology, store ice during off-peak electricity prices and release the ice to provide cooling during peak demand hours. This approach effectively reduces operational costs, balances grid load, and reduces carbon dioxide emissions (CDE). However, existing control methods typically rely on simple electricity price fluctuations and load variations, lacking effective emergency response capabilities for sudden grid load changes. This study presents a dual-stage collaborative optimization framework that synergistically integrates day-ahead scheduling with real-time intra-day control to enhance IAC system operational efficiency. In the day-ahead phase, a multi-objective optimization algorithm is formulated to dynamically allocate cooling loads between chillers and ice-melting processes, achieving simultaneous minimization of energy consumption and CDE. In the intra-day phase, a multi-agent deep reinforcement learning based dynamic control architecture is developed to coordinate efficient regulation under daily demand response (DDR) and emergency demand response (EDR) modes. The results show that under the dual-stage optimization strategy, the system's operating costs were reduced by 15.7 %, and CDE decreased by 15.0 % compared to conventional single-phase strategies. Under EDR conditions, the system participated in load response and obtained compensation benefits, reducing total costs by 81.67 %. The reduction rate remained consistently exceeding 25 %, achieving the expected reduction target, alleviating the burden on the power grid. The indoor temperature increased by no more than 4 °C, ensuring user comfort. This study provides an effective demand-side optimization paradigm for IAC systems DR in smart grid ecosystems. 2025-11-15T00:00:00Z