Browsing by Author "Xu, Yuchun"
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Item Open Access An autonomous system for maintenance scheduling data-rich complex infrastructure: Fusing the railways' condition, planning and cost(Elsevier, 2018-02-22) Durazo-Cardenas, Isidro; Starr, Andrew; Turner, Christopher J.; Tiwari, Ashutosh; Kirkwood, Leigh; Bevilacqua, Maurizio; Tsourdos, Antonios; Shehab, Essam; Baguley, Paul; Xu, YuchunNational railways are typically large and complex systems. Their network infrastructure usually includes extended track sections, bridges, stations and other supporting assets. In recent years, railways have also become a data-rich environment. Railway infrastructure assets have a very long life, but inherently degrade. Interventions are necessary but they can cause lateness, damage and hazards. Every day, thousands of discrete maintenance jobs are scheduled according to time and urgency. Service disruption has a direct economic impact. Planning for maintenance can be complex, expensive and uncertain. Autonomous scheduling of maintenance jobs is essential. The design strategy of a novel integrated system for automatic job scheduling is presented; from concept formulation to the examination of the data to information transitional level interface, and at the decision making level. The underlying architecture configures high-level fusion of technical and business drivers; scheduling optimized intervention plans that factor-in cost impact and added value. A proof of concept demonstrator was developed to validate the system principle and to test algorithm functionality. It employs a dashboard for visualization of the system response and to present key information. Real track incident and inspection datasets were analyzed to raise degradation alarms that initiate the automatic scheduling of maintenance tasks. Optimum scheduling was realized through data analytics and job sequencing heuristic and genetic algorithms, taking into account specific cost & value inputs from comprehensive task cost modelling. Formal face validation was conducted with railway infrastructure specialists and stakeholders. The demonstrator structure was found fit for purpose with logical component relationships, offering further scope for research and commercial exploitation.Item Open Access Benchmarking best practices in aerospace sector for the qualification and validation of medical devices(Cranfield University, 2012-09) Chen Chen, Hao; Tiwari, Ashutosh; Xu, YuchunThe validation stage in the development of a medical device plays a critical role as it demonstrates that the new product meets all the functional, reliability and quality requirements of both customer and regulatory authorities. Operating under a highly constrained process, where multiple requirements must be satisfied, the identification and implementation of innovative and improved methods can result in great cost and time savings. This project aims to develop a highly reliable and efficient procedure for the validation of medical devices. In order to achieve this, a qualitative approach has been adopted and a benchmarking study has been performed within the aerospace sector with the purpose of identifying and adapting the best practices into medical device validation procedures. The organisation current practices have been reviewed in order to identify improvement opportunities. Through several methods, including interviews, extensive literature and publications review, leading practices have been identified and proposed to the organisation. Finally, the implementation guidelines for the new procedures are provided in this research project. The outcomes of the study showed that the development of some critical procedures within the organisation, combined with an adequate resources allocation result in performance improvements and time-and-cost savings for the validation process. These results provide a starting-point for future studies basing on a quantitative approach and the particularisation of the benchmarking study scope.Item Open Access A bottom-up lean implementation study at a Malaysian automotive parts manufacturer(Cranfield University, 2014-04) Chay, Tick Fei; Xu, Yuchun; Tiwari, AshutoshThe aim of this research was to investigate shop floor employees’ involvement (including supervisory staffs) in lean implementation or Kaizen activities at a Malaysian automotive parts manufacturer leading in lean; and to propose a bottom-up lean conceptual model and its implementation roadmap to provoke involvement of shop floor employees in Kaizen. The research was carried out in five phases. First, the focus areas of Kaizen at Toyota and the critical success factors that would influence the extent of shop floor employees’ involvement in Kaizen activities were identified via literature review. Second, a case study was carried out at a Malaysian automotive parts manufacturer (known as Company A) with 7-years of intensive lean experience. The research data were collected via a semi-structured interview with the Lean Coordinator of the company, and a survey which addressed to different levels of internal stakeholder from top management to operators. Third, analyses on the extent of shop floor employees’ Kaizen involvement at Company A and the influences of each critical success factor were carried out. Fourth, a bottom-up lean conceptual model and its implementation roadmap incorporating the critical success factors were developed. Fifth, the proposed lean model and its implementation roadmap were validated by lean experts from both academia and industry. As a result, the study found the shop floor employees’ extent of involvement in Kaizen at Company A was low. The identified critical success factors namely F1 – top management’s commitment; F2 – shop floor employees’ commitment and technical capability; F3 – the stage of lean transformation; and F4 – shop floor responsibilities assignment were found to have significant influence on the extent of ‘Employee Involvement’. Being awarded as a Model Company in Malaysian automotive industry, Company A had yet to commence their transition to bottom-up approach phase in their lean journey although they had already enjoyed the early benefits of lean. The proposed model would thus serve as a general guideline to help the company or the Malaysian automotive industry in large in bottom-up approach lean implementation.Item Open Access Business process mining: From theory to practice(Emerald Group Publishing Limited, 2012-12-31T00:00:00Z) Turner, Christopher J.; Tiwari, Ashutosh; Olaiya, Richard; Xu, YuchunPurpose– The purpose of this paper is to present a comparison of a number of business process mining tools currently available in the UK market. An outline of the practice of business process mining is given, along with an analysis of the main techniques developed by academia and commercial entities. This paper also acts as a primer for the acceptance and further use of process mining in industry, suggesting future directions for this practice. Design/methodology/approach– Secondary research has been completed to establish the main commercial business process mining tool vendors for the market. A literature survey has also been undertaken into the latest theoretical techniques being developed in the field of business process mining. Findings– The authors have identified a number of existing commercially available business process mining tools and have listed their capabilities within a comparative analysis table. All commercially available business process mining tools included in this paper are capable of process comparison and at least 40 per cent of the tools claim to deal with noise in process data. Originality/value– The contribution of this paper is to provide a state-of-the-art review of a number of commercial business process mining tools available within the UK. This paper also presents a summary of the latest research being undertaken in academia in this subject area and future directions for the practice of business process mining.Item Open Access Business process mining: from theory to practice(Emerald Group Publishing Limited, 2012-06-01T00:00:00Z) Turner, Christopher J.; Tiwari, Ashutosh; Olaiya, Richard; Xu, YuchunPurpose - This paper presents a comparison of a number of business process mining tools currently available in the UK market. An outline of the practice of business process mining is given along with an analysis of the main techniques developed by academia and commercial entities. This paper also acts as a primer for the acceptance and further use of process mining in industry suggesting future directions for this practice. Design/methodology/approach –Secondary research has been completed to establish the main commercial business process mining tool vendors for the market. A literature survey has also been undertaken into the latest theoretical techniques being developed in the field of business process mining. Findings – The authors have identified a number of existing commercially available business process mining tools and have listed their capabilities within a comparative analysis table. All commercially available business process mining tools included in this paper are capable of process comparison and at least 40% of the tools claim to deal with noise in process data. Originality/value - The contribution of this paper is to provide a state of the art review of a number of commercial business process mining tools available within the UK. This paper also presents a summary of the latest research being undertaken in academia in this subject area and future directions for the practice of business process minItem Open Access Capturing and assessing the chemical milling process capability(Cranfield University, 2011-01) Sun, Yuhui; Xu, YuchunIn order to support the chemical milling process decision making on the new product producing, a process capability model is developed. The model uses process factors, capability measures and the assessing methods to capture the present chemical milling process capability on the new products. The inputs for this model implementation include a set of common product and production information. This model covers a wide range of capability measures, which are recommended by the manufacturing engineers. Despite of traditional statistical capability indices such as Cp/Cpk, this research assesses the chemical milling process capability within the manufacturing system which consists of process, product and resource. The estimations about chemical milling process capacity and process efficiency are covered in the model’s implementation.Item Open Access Develop a framework for engineering change management in an aircraft manufacturing company(Cranfield University, 2014-08) Zhu, Lin; Xu, Yuchun; Starr, AndrewThe purpose of this research project is to develop a framework for engineering change management (ECM) in an aircraft manufacturing company. ECM is vital for manufacturers to manage changes efficiently and effectively. As an effective change control technique, ECM has been widely practiced in different industrial sectors. However, adopting an ECM process does not always guarantee the agility of the manufacturing process of the manufacturer. The performance of ECM could be affected by the actual practice followed by the ECM practitioner. The research was conducted in four phases. In the first phase an extensive literature review was carried out to understand the critical success factors related to the ECM and Configuration Management (CM) activities. The second phase was to model the current ECM practice in the aircraft manufacturing company by using IDEF0 approach. The actual ECM practice was understood and some gaps were identified in this part. In the third phase, a survey was carried out to identify the best practices in aerospace and automobile companies. A list of best practices that could promote the performance of the ECM was identified by analysing the result of the survey. In the last phase of the research, a framework was developed from the model of current ECM process in the company. The best ECM practices identified in the third part of the research were integrated into the model to refine the current ECM process. The framework was validated by experts in the aircraft manufacturing company. The outcome of this research shows the correlation between the performance of the ECM process and the actual ECM practices. And the framework developed in this thesis can provide benefits for the further improvement of the current ECM process in the aircraft company. The framework also offers a benchmarking reference for other companies with a similar background to examine their own ECM process and initiate improvement.Item Open Access Development of a framework for assessing the economic benefit of remanufacturing(Cranfield University, 2009-09) Jakpa, Onome, E.; Xu, YuchunProduct waste is becoming a big problem in our life. In order to reduce waste and efficiently use resources, product can be remanufactured, and its materials can be recycled to achieve better sustainability. In comparison with recycling materials, remanufacturing products can retain all the value added, so potentially it has high profitability and sustainability. Despite its main advantage of retaining the value of the products, remanufacturing is an area that is not widely practiced due to the high costs of remanufacturing and reverse logistics facilities. As a result of this, the cost components had to be researched in order to ascertain the costs involved in the process of remanufacturing. The identification the cost drivers in each of the process provided the basis for a generic framework to be developed which gives remanufacturers a template to determine the economic benefits of remanufacturing from a whole systems point of view including the reverse logistics. Through the use of a specified methodology, this research aims to capture all the costs involved in the whole systems remanufacturing process given that the previous models that exist do not propose a costing model for both reverse logistics and remanufacturing. Ready to Use Additive Manufacturing – RUAM is a technique for creating robust three dimensional metal objects. It is application in the framework allows for the refabrication of EOL products.Item Open Access Feature based cost and carbon emission modelling for wire and arc additive manufacturing(Cranfield University, 2012-12) Guo, Jianing; Mehnen, Jorn; Xu, YuchunThe wire and arc additive manufacturing (WAAM) is a CNC and welding deposition based additive manufacturing method. This novel manufacturing technique has potential cost and environment advantage and was developed as an ideal alternative for industrial sustainable development. The aim of this project is to develop a cost and carbon emission model primarily for the WAAM manufacturing cost (£) calculation and secondly for the WAAM carbon emission (KgCO2e) estimation, which can be used by the decision makers and design engineers in product design stage without detailed process information. Literature review and an industry survey were carried out first to capture the overview of this research context and the essential data for cost modelling. Then the cost breakdown structure (CBS) and cost drivers were determined. Thereafter, a feature based cost model and detailed cost equations were developed. A specific Greenhouse Gases (GHG) emission model was also established which follows the specification of existing carbon footprint measurement standards. As part of this project, an integrated software tool was developed by using MS Visual Basic language. The proposed cost and GHG emission model were implemented in this software. With the ability of directly capture geometry data from CAD files and fully automatic calculation, the software tool is efficient and convenient. Three case studies were conducted to demonstrate the proposed cost model and software tool. The comparative cost analyses with other conventional manufacturing methods were also discussed in these case studies. Finally, the capacity and reliability of the cost software were validated by experts from industry and academia. The implementation of the research outcomes of this project can achieve accurate early cost estimation for WAAM conveniently. Moreover, it can clarify the cost and environment advantage of WAAM and assist to identify the most suitable situation for adopting WAAM from a cost and sustainable point of view.Item Open Access Gesture detection towards real-time ergonomic analysis for intelligent automation assistance(Springer, 2016-07-10) Mgbemena, Chika Edith; Oyekan, John; Tiwari, Ashutosh; Xu, Yuchun; Fletcher, Sarah R.; Hutabarat, Windo; Prabhu, Vinayak AshokManual handling involves transporting of load by hand through lifting or lowering and operators on the manufacturing shop floor are daily faced with constant lifting and lowering operations which leads to Work-Related Musculoskeletal Disorders. The trend in data collection on the Shop floor for ergonomic evaluation during manual handling activities has revealed a gap in gesture detection as gesture triggered data collection could facilitate more accurate ergonomic data capture and analysis. This paper presents an application developed to detect gestures towards triggering real-time human motion data capture on the shop floor for ergonomic evaluations and risk assessment using the Microsoft Kinect. The machine learning technology known as the discrete indicator—precisely the AdaBoost Trigger indicator was employed to train the gestures. Our results show that the Kinect can be trained to detect gestures towards real-time ergonomic analysis and possibly offering intelligent automation assistance during human posture detrimental tasks.Item Open Access Improving Just-in-Time manufacturing operations by using Internet of Things based solutions(Elsevier, 2016-11-16) Xu, Yuchun; Chen, M.Just in time (JIT) manufacturing is one of the main methodologies used to enhance manufacturers’ competitiveness through inventory and lead time reduction. However implementing JIT has some challenges, e.g. lack of required information sharing or communication between stakeholders, insufficient sound action or planning system etc. Internet of Things (IoT) technology has the potential to be used for acquiring data and information in real time to facilitate dynamic JIT manufacturing. This paper presents a research on using IoT based solution to enhance JIT manufacturing. The general challenges of JIT implementation are identified first, then an IoT based solution is proposed to address the JIT challenges in a selected case study. A framework to support the proposed IoT solution is developed and its implementation steps are suggested.Item Open Access Lean implementation frameworks: The challenges for SMEs(Elsevier, 2017-07-11) Almanei, Mohammed; Salonitis, Konstantinos; Xu, YuchunImplementation of lean manufacturing in any type of organizations can bring many benefits, such as reducing waste and improving operating efficiency. However, lean implementation is not a straightforward process. Although a number of frameworks have been presented, still many companies find it difficult to implement lean. Furthermore, most of these roadmaps are for large manufacturing companies, and not for small and medium enterprises. Unfortunately, there is not a recipe that if used can guarantee a successful implementation. Furthermore, unsuccessful implementation can have a great impact on organization's resources, but even more importantly, affect employees and their confidence in lean philosophy. In the present paper, the most prominent lean implementation frameworks will be discussed, under the prism of the needs of SMEs. The challenges for the SMEs in their lean journey are discussed. Paper originally presented at Manufacturing Systems 4.0 – Proceedings of the 50th CIRP Conference on Manufacturing Systems, held 3 – 5 May, 2017, Taichung City, Taiwan.Item Open Access An Ontology for Product-Service Systems(Cranfield University, 2010) Annamalai Vasantha, Gokula Vijaykumar; Hussain, Romana; Cakkol, Mehmet; Roy, Rajkumar; Evans, Stephen; Tiwari, Ashutosh; Xu, YuchunIndustries are transforming their business strategy from a product-centric to a more service-centric nature by bundling products and services into integrated solutions to enhance the relationship between their customers. Since Product- Service Systems design research is currently at a rudimentary stage, the development of a robust ontology for this area would be helpful. The advantages of a standardized ontology are that it could help researchers and practitioners to communicate their views without ambiguity and thus encourage the conception and implementation of useful methods and tools. In this paper, an initial structure of a PSS ontology from the design perspective is proposed and evaluated.Item Open Access Optimise repair strategy selection and repair knowledge sharing to support aero engine design.(Cranfield University, 2015-11) Khan, Atif M.; Xu, Yuchun; Starr, AndrewRecent growth in aviation industry, large civil jet engines OEMs (Original Equipment Manufacturer) and MROs ((Maintenance, Repair and overhaul)) have emphasised on decreased profits, poor technology selections and maintenance focused design. This has generated service based approach in their selling, offering all customers’ requirements, known as servitisation. The servitisation has increased profits but did not solve the challenges of poor technology selection and design. The difficulties involved within servitisation entails rationalised decision making often with high risk and very limited information. This thesis assesses the most suitable Multi-criteria decision making (MCDM) in concurrence with OEMs and MRO focus groups that recognises the industrial requirements and proposed a novel selection method which is an AHP algorithm based on MCDM in efforts to address business KPIs in aero engine servitisation. This AHP algorithm based MCDM develops an optimised repair process/technology selection framework which is called ORSS (Optimised Repair Selection Strategy). The ORSS applies the business KPIs (Quality Cost Delivery) as a selection criteria combined with the repair engineer's requirements and expert's evaluation of processes/technologies based on a component and its damage-mode to provide the optimised repair process/technology selection that also compliments the components lifecycle repair strategy. A structured knowledge sharing framework has also been developed. This consists of the information that the designers can update to help repair teams to become more effective and efficient in repair and services critical information tasks. These frameworks were validated successfully by experts within the design, repair and service teams at Rolls Royce. These frameworks have shown high levels of improvements in repair process selection and the key knowledge sharing for designs.Item Open Access Real-time evaluation and feedback system for ergonomics on the shop floor.(2017-09) Mgbemena, Chika Edith; Tiwari, Ashutosh; Xu, YuchunDespite the greatly increased automation in manufacturing industries, manual operations still exist, and ergonomic risk factors that arise because of manual operations can lead to Work-Related Musculoskeletal Disorders (WMSDs). To mitigate the risk, manual operations should be assessed to identify if any risk, such as awkward posture, exist. Most assessments are carried out offline but this cannot alert and prevent operators from adopting awkward postures in time. Hence, due to the popularity of flexible manufacturing systems that require immediate response to changes, there is need for a real-time assessment. Therefore, the aim of this research is to develop a real-time knowledge-based ergonomic assessment system for use in the real-time evaluation of work postures on the shop floor and provision of feedback to workers, using 3D motion sensors. The developed intelligent system utilizes the knowledge from health and safety (H&S) guidelines, set of rules and an inference engine, to automatically capture and assess worker’s postures and provide real-time feedback to the worker through an easy-to-understand user interface. The system has been validated using many case studies which include the posture assessment of: 6 operators assembling engine valve, 4 seated researchers conducting desk-based reading and 15 operators during lifting, assembly and hammering of IKEA table. The system when tested proved to achieve: real-time assessment, easy-to-understand feedback, reliable measurements with Cronbach’s alpha of 0.978, p=0.045 and Kendall’s coefficient of concordance of 0.634, p = 0.000. The main contribution of this work lies in providing real-time feedback to workers. This contribution is in three sub-areas namely: i) Development of a real-time Kinect-based tool for H&S-compliant ergonomic assessment. ii) Development of a knowledge-based real-time feedback system for improved posture assessment. iii) Provision of real-time feedback to alert workers in time. The novelty of this research is in the development of a knowledge-based system for real-time ergonomic assessment and feedback to workers using 3D motion sensors.Item Open Access The role of leadership in implementing lean manufacturing(Elsevier, 2017-07-11) Alefari, Mudhafar; Salonitis, Konstantinos; Xu, YuchunIt is widely accepted that for the successful implementation of lean manufacturing, the senior management commitment is of great importance. However, the lean journey is usually a long one, and eventually management commitment creeps. Furthermore, the involvement of employees in daily improvements is also critical for the success of implementation. Lean leadership can be considered as a way of sustaining and improving the employee performance in lean production systems. In the present study, a thorough literature review is presented focusing in reviewing the principles of lean leadership and the practices that can lead in improving the employee performance. Furthermore, the characteristics and qualities of lean leader are discussed Paper originally presented at Manufacturing Systems 4.0 – Proceedings of the 50th CIRP Conference on Manufacturing Systems, held 3 – 5 May, 2017, Taichung City, Taiwan.