Design, procurement and construction strategies for minimizing waste in construction projects

The construction industry contributes the largest portion of waste to landfill, and it consumes a significant proportion of mineral resources excavated from nature. Due to adverse environmental impacts of waste generation, as well as financial gains associated with its minimization, waste intensiveness of the industry has remained a major concern across nations. This study investigates the design, procurement and construction strategies for waste minimization, using a dynamic approach. Apart from an investigation of the key and underlying measures for construction waste mitigation, the study considers the interrelationship between stages of projects' lifecycle. This is as activities carried out at an earlier stage are capable of engendering occurrences at later stages of the dynamic project delivery processes. Following the tenets of critical realism philosophy and exploratory sequential mixed method, the study combined qualitative and quantitative approaches at intensive and extensive stages respectively. At the early stage of the study, data were collected through literature review and focus group discussions with industry experts. Results of the qualitative study were used to develop a questionnaire, which was analysed using statistical approach and structural equation modelling. As a means of investigating the key drivers of waste minimization at a holistic level, a system dynamic model was developed to simulate the interplay and effects of different strategies that were confirmed through the previous process. The study suggests that design stage has the most decisive impacts on construction waste minimization. At this stage, the key dimensions for designing out waste include design for modern methods of construction, collaborative design process, design for standardisation and waste-efficient design documentation. Error-free design and involvement of contractors at early design stage are part of the critical success factors for designing out waste. With design being much important for waste minimization, competencies of design in terms of waste behavioural competency, design task proficiency, construction-related knowledge and inter-professional collaborative competency are essential for designing out waste. Materials procurement process could enhance waste minimization by considering its key dimensions for driving waste-efficient projects, which includes waste-efficient materials purchase management, suppliers' alliance and waste-efficient bill of quantity. Efficient materials take-off and take back scheme are confirmed as critical success factors for driving waste minimization through materials procurement processes. During construction activities, waste could be reduced through prefabrication and offsite technology, contractual requirements, maximisation of materials reuse and improved collaboration, among others. Prefabrication, supply chain alliance and collaborative procurement routes are confirmed as the critical success factors for reducing waste during construction process. Dynamic interplay among these sets of strategies suggests that notwithstanding the significance of the different measures during design, procurement and construction processes, prefabrication technology and collaborative procurement route are the holistic drivers of construction waste minimisation. The study implies that designers could effectively drive waste minimization through dimensional coordination and standardisation of design in line with standard materials supplies. In addition to the need for prefabrication and offsite technologies, increasing collaboration among project team is requisite to reducing waste generated by construction activities. By implementing the strategies suggested in the study, substantial proportion of construction waste would be diverted from landfill

A PREDICTIVE PROBABILITY INTERIM DESIGN FOR PHASE II CLINICAL TRIALS WITH CONTINUOUS ENDPOINTS

Phase II clinical trials aim to potentially screen out ineffective and identify effective therapies to move forward to randomized phase III trials. Single-arm studies remain the most utilized design in phase II oncology trials, especially in scenarios where a randomized design is simply not practical. Due to concerns regarding excessive toxicity or ineffective new treatment strategies, interim analyses are typically incorporated in the trial, and the choice of statistical methods mainly depends on the type of primary endpoints. For oncology trials, the most common primary objectives in phase II trials include tumor response rate (binary endpoint) and progression disease-free survival (time-to-event endpoint). Interim strategies are well-developed for both endpoints in single-arm phase II trials. The advent of molecular targeted therapies, often with lower toxicity profiles from traditional cytotoxic treatments, has shifted the drug development paradigm into establishing evidence of biological activity, target modulation and pharmacodynamics effects of these therapies in early phase trials. As such, these trials need to address simultaneous evaluation of safety as well as proof-of-concept of biological marker activity or changes in continuous tumor size instead of binary response rates. In this dissertation, we extend a predictive probability design for binary outcomes in the single-arm clinical trial setting and develop two interim designs for continuous endpoints, such as continuous tumor shrinkage or change in a biomarker over time. The two-stage design mainly focuses on the futility stopping strategies, while it also has the capacity of early stopping for efficacy. Both optimal and minimax designs are presented for this two-stage design. The multi-stage design has the flexibility of stopping the trial early either due to futility or efficacy. Due to the intense computation and searching strategy we adopt, only the minimax design is presented for this multi-stage design. The multi-stage design allows for up to 40 interim looks with continuous monitoring possible for large and moderate effect sizes, requiring an overall sample size less than 40. The stopping boundaries for both designs are based on predictive probability with normal likelihood and its conjugated prior distributions, while the design itself satisfies the pre-specified type I and type II error rate constraints. From simulation results, when compared with binary endpoints, both designs well preserve statistical properties across different effect sizes with reduced sample size. We also develop an R package, PPSC, and detail it in chapter four, so that both designs can be freely accessible for use in future phase II clinical trials with the collaborative efforts of biostatisticians. Clinical investigators and biostatisticians have the flexibility to specify the parameters from the hypothesis testing framework, searching ranges of the boundaries for predictive probabilities, the number of interim looks involved and if the continuous monitoring is preferred and so on

A New Consumerism: The influence of social technologies on product design

Social media has enabled a new style of consumerism. Consumers are no longer passive recipients; instead they are assuming active and participatory roles in product design and production, facilitated by interaction and collaboration in virtual communities. This new participatory culture is blurring the boundaries between the specific roles of designer, consumer and producer, creating entrepreneurial opportunities for designers, and empowering consumers to influence product strategies. Evolving designer-consumer interactions are enabling an enhanced model of co-production, through a value-adding social exchange that is driving changes in consumer behaviour and influencing both product strategies and design practice. The consumer is now a knowledgeable participant, or prosumer, who can contribute to user–centered research through crowd sourcing, collaborate and co-create through open-source or open-innovation platforms, assist creative endeavors by pledging venture capital through crowd funding and advocate the product in blogs and forums. Social media- enabled product implementation strategies working in conjunction with digital production technologies (e.g. additive manufacture), enable consumer-directed adaptive customisation, product personalisation, and self-production, with once passive consumers becoming product produsers. Not only is social media driving unprecedented consumer engagement and significant behavioural change, it is emerging as a major enabler of design entrepreneurship, creating new collaborative opportunities. Innovative processes in design practice are emerging, such as the provision of digital artifacts and customisable product frameworks, rather than standardised manufactured solutions. This paper examines the influence of social media-enabled product strategies on the methodology of the next generation of product designers, and discusses the need for an educational response

Implementing 5D BIM on construction projects: Contractor perspectives from the UK construction sector

This is an accepted manuscript of an article published by Emerald in Journal of Engineering, Design and Technology on 09/05/2020: https://doi.org/10.1108/JEDT-01-2020-0007 The accepted version of the publication may differ from the final published version.Purpose The purpose of this paper is to report on primary research findings that sought to investigate and analyse salient issues on the implementation of 5D building information modelling (BIM) from the UK contractors’ perspective. Previous research and efforts have predominantly focussed on the use of technologies for cost estimation and quantity takeoff within a more traditional-led procurement, with a paucity of research focussing on how 5D BIM could facilitate costing within contractor-led procurement. This study fills this current knowledge gap and enhances the understanding of the specific costing challenges faced by contractors in contractor-led projects, leading to the development of 5D framework for use in future projects. Design/methodology/approach To develop a fully detailed understanding of the challenges and issues being faced in this regard, a phenomenological, qualitative-based study was undertaken through interviews involving 21 participants from UK-wide construction organisations. A thematic data analytical process was applied to the data to derive key issues, and this was then used to inform the development of a 5D-BIM costing framework. Findings Multi-disciplinary findings reveal a range of issues faced by contractors when implementing 5D BIM. These exist at strategic, operational and technological levels which require addressing successful implementation of 5D BIM on contractor-led projects adhering to Level 2 BIM standards. These findings cut across the range of stakeholders on contractor-led projects. Ultimately, the findings suggest strong commitment and leadership from organisational management are required to facilitate cost savings and generate accurate cost information. Practical implications This study highlights key issues for any party seeking to effectively deploy 5D BIM on a contractor-led construction project. A considerable cultural shift towards automating and digitising cost functions virtually, stronger collaborative working relationship relative to costing in design development, construction practice, maintenance and operation is required. Originality/value By analysing findings from primary research data, the work concludes with the development of a 5D BIM costing framework to support contractor-led projects which can be implemented to ensure that 5D BIM is successfully implemented