Development of a semantic knowledge modelling approach for evaluating offsite manufacturing production processes

The housing sector in the UK and across the globe is constantly under pressure to deliver enough affordable houses to meet the increasing demand. Offsite Manufacturing (OSM), a modern method of construction, is considered to be a key aspect in meeting these demands given its potential to increase efficiency and boost productivity. Although the use of OSM to increase the supply of affordable and efficient homes is getting popular, the focus has been on ‘what’ methods of construction are used (i.e. whether implementing OSM or traditional approach) rather than ‘how’ the alternative construction approach shall be done (i.e. choice of OSM method to meet set objectives). There have been criticisms of the approaches used by professionals implementing OSM methods as some of these approaches are non-structured and these methods have been criticised for being similar to the conventional onsite methods with little process gains. There are previous studies that have compared the performance of OSM and other modern methods of construction with conventional methods of construction. However, there is hardly any attempt nor quantitative evidence comparing the performance of various competing OSM approaches (i.e. methods with standardised and non-standardised processes) in order to support stakeholders in making an informed decision on choices of methods. In pursuit of the research gap identified, this research aims to develop a proof-of-concept knowledge-based process analysis tool that would enable OSM practitioners to efficiently evaluate the performances of their choice of OSM methods to support informed decision-making and continuous improvement. To achieve this aim, an ontology knowledge modelling approach was adopted for leveraging data and information sources with semantics, and an offsite production workflow (OPW) ontology was developed to enable a detailed analysis of OSM production methods. The research firstly undertook an extensive critical review of the OSM domain to identify the existing OSM knowledge and how this knowledge can be formalised to aid communication in the OSM domain. In addition, a separate review of process analysis methods and knowledge-based modelling methods was done concurrently to identify the suitable approach for analysing and systemising OSM knowledge respectively. The lean manufacturing value system analysis (VSA) approach was used for the analysis in this study using two units of analysis consisting of an example of atypical non-standardised (i.e. static method of production) and standardised (i.e. semi-automated method of production) OSM methods. The knowledge systematisation was done using an ontology knowledge modelling approach to develop the process analysis tool – OPW ontology. The OPW ontology was further evaluated by mapping a case of lightweight steel frame modular house production to model a real-life context. A two-staged validation approach was then implemented to test the ontology which consists of firstly an internal validation of logic and consistency of the results and then an expert validation process using an industry-approved set of criteria. The result from the study revealed that the non-standardised ad-hoc OSM production method, involving a significant amount of manual tasks, contributes little process improvement from the conventional onsite method when using the metrics of process time and cost. In comparison with the structured method e.g. semi-automated OSM production method, it is discovered that the process cost and time are 82% and 77% more in the static method respectively based on a like-to-like production schedule. The study also evaluates the root causes of process wastes, accounting for non-value-added time and cost consumed. The results contribute to supporting informed decision-making on the choices of OSM production methods for continuous improvement. The main contributions to knowledge and practice are as follows: i. The output of this research contributes to the body of literature on offsite concepts, definition and classification, through the generic classification framework developed for the OSM domain. This provides a means of supporting clear communication and knowledge sharing in the domain and supports knowledge systematisation. ii. The approach used in this research, integrating the value system analysis (VSA) and activity-based costing (ABC) methods for process analysis is a novel approach that bridges that gaps with the use of the ABC method for generating detailed process-related data to support cost/time-based analysis of OSM processes. iii. The developed generic process map which represents the OSM production process captures activity sequences, resources and information flow within the process will help in disseminating knowledge on OSM and improve best practices in the industry. iv. The developed process analysis tool (the OPW ontology) has been tested with a real-life OSM project and validated by domain experts to be a competent tool. The knowledge structure and rules integrated into the OPW ontology have been published on the web for knowledge sharing and re-use. This tool can be adapted by OSM practitioners to develop a company-specific tool that captures their specific business processes, which can then support the evaluation of their processes to enable continuous improvement

Process Waste Analysis for Offsite Production Methods for House Construction: A Case Study of Factory Wall Panel Production

There is a growing interest in the use of offsite manufacturing (OSM) in the construction industry disregarding criticisms of lacking real improvement from some offsite approaches adopted by housebuilders as compared to their onsite counterparts. Quantitative performance measures from previous studies are based on conventional onsite methods, with little attention paid to the performance and process improvements derived from various OSM methods. In response, a case study was conducted based on two OSM methods using standardized and non-standardized processes for the production stage of a factory-manufactured wall panel. Value system analysis and root cause analysis using the 5Whys method was adopted to evaluate possible improvements in terms of process waste. The study reveals that OSM production methods that replicate site arrangements and activities involving significant manual tasks do not necessarily provide a marked improvement from the conventional onsite method. Thus, there is a need to re-evaluate the processes involved to eliminate such embedded process wastes as non-value-added time and cost and to consider automating critical activities. The analysis adopted in the case study provides measurable evidence of the performance gained from having a structured workflow over a non-structured workflow. It also reveals how process wastes are generated in the production process of wall panels offsite

Towards an Ontology-Based Approach to Measuring Productivity for Offsite Manufacturing Method

The steady decline of manual and skilled trades in the construction industry has increased the recognition of offsite manufacturing (OSM), an aspect of Design for Manufacture and Assembly (DFMA) methods as one way to boost productivity and performance. However, existing productivity estimation approaches are carried out in isolation thus limiting the sort of result obtained from such systems. Also, there is yet to be a holistic approach that enables productivity estimation using different metrics and integrates experts’ knowledge to predict productivity and guide decision making at the early development stage of a project. This study aims to develop a method that can be used to generate multiple estimations for all these metrics simultaneously through linking their relationships. An ontology-based knowledge modelling approach for estimating productivity at the production stage for OSM projects is proposed. A case study of panel system offsite is used as a proof-of-concept for data collection and knowledge modelling in an ontology. Results from the study through the use of rules and semantic reasoning retrieved cost estimates and time schedule for a panel system production with considerations for different design choices. It is thus proven that systemising the production process knowledge of OSM methods enables practitioners to make informed choices on product design to best suit productivity requirements. The developed method helps to reduce the level of uncertainty by encouraging measurable evidence and allows for better decision-making on productivity

Demystifying the concept of offsite manufacturing method: Towards a robust definition and classification system

Purpose This study aims to develop a more inclusive working definition and a formalised classification system for offsite construction to enable common basis of evaluation and communication. Offsite manufacturing (OSM) is continuously getting recognised as a way to increase efficiency and boost productivity of the construction industry in many countries. However, the knowledge of OSM varies across different countries, construction practices and individual experts thus resulting into major misconceptions. The lack of consensus of what OSM is and what constitutes its methods creates a lot of misunderstanding across Architecture Engineering and Construction (AEC) industry professionals, therefore, inhibiting a global view and understanding for multicultural collaboration. Therefore, there is a need to revisit these issues with the aim to develop a deep understanding of the concepts and ascertain what is deemed inclusive or exclusive. Design/methodology/approach A state-of-the-art review and analysis of literature on OSM was conducted to observe trends in OSM definitions and classifications. The paper identifies gaps in existing methods and proposes a future direction. Findings Findings suggest that classifications are mostly aimed towards a particular purpose and existing classification system are not robust enough to cover all aspects. Therefore, there is need to extend these classification systems to be fit for various purposes. Originality/value This paper contributes to the body of literature on offsite concepts, definition and classification, and provides knowledge on the broader context on the fundamentals of OSM

Development of a semantic knowledge modelling approach for evaluating offsite manufacturing production processes

The housing sector in the UK and across the globe is constantly under pressure to deliver enough affordable houses to meet the increasing demand. Offsite Manufacturing (OSM), a modern method of construction, is considered to be a key aspect in meeting these demands given its potential to increase efficiency and boost productivity. Although the use of OSM to increase the supply of affordable and efficient homes is getting popular, the focus has been on ‘what’ methods of construction are used (i.e. whether implementing OSM or traditional approach) rather than ‘how’ the alternative construction approach shall be done (i.e. choice of OSM method to meet set objectives). There have been criticisms of the approaches used by professionals implementing OSM methods as some of these approaches are non-structured and these methods have been criticised for being similar to the conventional onsite methods with little process gains. There are previous studies that have compared the performance of OSM and other modern methods of construction with conventional methods of construction. However, there is hardly any attempt nor quantitative evidence comparing the performance of various competing OSM approaches (i.e. methods with standardised and non-standardised processes) in order to support stakeholders in making an informed decision on choices of methods. In pursuit of the research gap identified, this research aims to develop a proof-of-concept knowledge-based process analysis tool that would enable OSM practitioners to efficiently evaluate the performances of their choice of OSM methods to support informed decision-making and continuous improvement. To achieve this aim, an ontology knowledge modelling approach was adopted for leveraging data and information sources with semantics, and an offsite production workflow (OPW) ontology was developed to enable a detailed analysis of OSM production methods. The research firstly undertook an extensive critical review of the OSM domain to identify the existing OSM knowledge and how this knowledge can be formalised to aid communication in the OSM domain. In addition, a separate review of process analysis methods and knowledge-based modelling methods was done concurrently to identify the suitable approach for analysing and systemising OSM knowledge respectively. The lean manufacturing value system analysis (VSA) approach was used for the analysis in this study using two units of analysis consisting of an example of atypical non-standardised (i.e. static method of production) and standardised (i.e. semi-automated method of production) OSM methods. The knowledge systematisation was done using an ontology knowledge modelling approach to develop the process analysis tool – OPW ontology. The OPW ontology was further evaluated by mapping a case of lightweight steel frame modular house production to model a real-life context. A two-staged validation approach was then implemented to test the ontology which consists of firstly an internal validation of logic and consistency of the results and then an expert validation process using an industry-approved set of criteria. The result from the study revealed that the non-standardised ad-hoc OSM production method, involving a significant amount of manual tasks, contributes little process improvement from the conventional onsite method when using the metrics of process time and cost. In comparison with the structured method e.g. semi-automated OSM production method, it is discovered that the process cost and time are 82% and 77% more in the static method respectively based on a like-to-like production schedule. The study also evaluates the root causes of process wastes, accounting for non-value-added time and cost consumed. The results contribute to supporting informed decision-making on the choices of OSM production methods for continuous improvement. The main contributions to knowledge and practice are as follows: i. The output of this research contributes to the body of literature on offsite concepts, definition and classification, through the generic classification framework developed for the OSM domain. This provides a means of supporting clear communication and knowledge sharing in the domain and supports knowledge systematisation. ii. The approach used in this research, integrating the value system analysis (VSA) and activity-based costing (ABC) methods for process analysis is a novel approach that bridges that gaps with the use of the ABC method for generating detailed process-related data to support cost/time-based analysis of OSM processes. iii. The developed generic process map which represents the OSM production process captures activity sequences, resources and information flow within the process will help in disseminating knowledge on OSM and improve best practices in the industry. iv. The developed process analysis tool (the OPW ontology) has been tested with a real-life OSM project and validated by domain experts to be a competent tool. The knowledge structure and rules integrated into the OPW ontology have been published on the web for knowledge sharing and re-use. This tool can be adapted by OSM practitioners to develop a company-specific tool that captures their specific business processes, which can then support the evaluation of their processes to enable continuous improvement

African BIM Report 2020

While it may seem like the adoption of Building Information Modelling (BIM) across Africa is slow-paced, the increasing advocacy efforts from various stakeholders is now resulting in a widespread drive for implementation and deployment. Coupled with the ongoing disruption by the global COVID-19 pandemic, there is now a very high degree of the utilization of digital technologies by construction professionals. As a first of its kind across the continent, the African BIM Report was conceived to provide a continuous review of the state of implementation of BIM by the industry. The report will progressively highlight exceptional projects, industry leaders and research experts across Africa. A pan-African survey will integrate the opinion from a wider range of professionals. As a dynamic, future-focused, and thriving community, BIM Africa is well-positioned to champion the digital transformation of the built industry across Africa. Our approach covers broad industry education, extensive research, professional development and certifications, quality networking and the formulation of locally adapted standards. Our Research and Development Committee comprises of a thriving portfolio of internationally certified and brilliant academic researchers of African descent; the coming together of bright minds to impact their motherland