Sanjita Jaipuria and Siba Sankar Mahapatra
The purpose of this paper is to propose a forecasting model to predict the demand under uncertain environment to control the bullwhip effect (BWE) considering review-period…
Abstract
Purpose
The purpose of this paper is to propose a forecasting model to predict the demand under uncertain environment to control the bullwhip effect (BWE) considering review-period order-up-to level ((R, S)) inventory control policy and its different variants such as (R, βS) (R, γO) and (R, γO, βS) proposed by Jakšič and Rusjan, (2008) and Bandyopadhyay and Bhattacharya (2013).
Design/methodology/approach
A hybrid forecasting model has been developed by combining the feature of discrete wavelet transformation (DWT) and an intelligence technique, multi-gene genetic programming (MGGP), denoted as DWT-MGGP. Performance of DWT-MGGP model has been verified under (R, S) inventory control policy considering demand from three different manufacturing companies.
Findings
A comparison between DWT-MGGP model and autoregressive integrated moving average forecasting model has been done by estimating forecast error and BWE. Further, this study has been extended with analysing the behaviour of BWE considering different variants of (R, S) policy such as (R,βS) (R, γO) and (R,γO,βS) and found that BWE can be moderated by controlling the inventory smoothing (β) and order smoothing parameters (γ).
Research limitations/implications
This study is limited to different variants of (R, S) inventory control policy. However, this study can be further extended to continuous review policy.
Practical implications
The proposed DWT-MGGP model can be used as a suitable demand forecasting model to control the BWE when (R, S), (R,βS) (R,γO) and (R,γO,βS)inventory control policies are followed for replenishment.
Originality/value
This study analyses the behavior of BWE through controlling the inventory smoothing (β) and order smoothing parameters (γ) when demand is predicted using DWT-MGGP forecasting model and order is estimated using (R, S), (R,βS) (R,γO) and (R,γO,βS) inventory control policies.
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L.C. Hieu, E. Bohez, J. Vander Sloten, H.N. Phien, E. Vatcharaporn, P.H. Binh, P.V. An and P. Oris
Design methods for medical rapid prototyping (RP) of personalized cranioplasty implants are presented in this paper. These methods are applicable to model cranioplasty implants…
Abstract
Design methods for medical rapid prototyping (RP) of personalized cranioplasty implants are presented in this paper. These methods are applicable to model cranioplasty implants for all types of the skull defects including beyond‐midline and multiple defects. The methods are based on two types of anatomical data, solid bone models (STereoLithography files – STL) and bone slice contours (Initial Graphics Exchange Specification – IGES and StrataSys Layer files – SSL). The bone solids and contours are constructed based on computed tomography scanning data, and these data are generated in medical image processing and STL slicing packages.
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Abstract
Purpose
Aims to investigate medical rapid prototyping (medical RP) technology applications and methods based on reverse engineering (RE) and medical imaging data.
Design/methodology/approach
Medical image processing and RE are applied to construct three‐dimensional models of anatomical structures, from which custom‐made (personalized) medical applications are developed.
Findings
The investigated methods were successfully used for design and manufacturing of biomodels, surgical aid tools, implants, medical devices and surgical training models. More than 40 medical RP applications were implemented in Europe and Asia since 1999.
Research limitations/implications
Medical RP is a multi‐discipline area. It involves in many human resources and requires high skills and know‐how in both engineering and medicine. In addition, medical RP applications are expensive, especially for low‐income countries. These practically limit its benefits and applications in hospitals.
Practical implications
In order to transfer medical RP into hospitals successfully, a good link and close collaboration between medical and engineering sites should be established. Moreover, new medical applications should be developed in the way that does not change the traditional approaches that medical doctors (MD) were trained, but provides solutions to improve the diagnosis and treatment quality.
Originality/value
The presented state‐of‐the‐art medical RP is applied for diagnosis and treatment in the following medical areas: cranio‐maxillofacial and dental surgery, neurosurgery, orthopedics, orthosis and tissue engineering. The paper is useful for MD (radiologists and surgeons), biomedical and RP/CAD/CAM engineers.
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Michèle Truscott, Deon de Beer, George Vicatos, Keith Hosking, Ludrick Barnard, Gerrie Booysen and R. Ian Campbell
The last decade has seen major advances in rapid prototyping (RP), with it becoming a multi‐disciplinary technology, crossing various research fields, and connecting continents…
Abstract
Purpose
The last decade has seen major advances in rapid prototyping (RP), with it becoming a multi‐disciplinary technology, crossing various research fields, and connecting continents. Process and material advancements open up new applications and manufacturing (through RP) is serving non‐traditional industries. RP technology is used to support rapid product development (RPD). The purpose of this paper is to describe how the Integrated Product Development research group of the Central University of Technology, Free State, South Africa is applying various CAD/CAM/RP technologies to support a medical team from the Grootte Schuur and Vincent Palotti hospitals in Cape Town, to save limbs – as a last resort at a stage where conventional medical techniques or practices may not apply any longer.
Design/methodology/approach
The paper uses action research to justify the proposal of a new method to use CAD/CAM/RP related technologies to substitute lost/damaged bone regions through the use of CT to CAD to.STL manipulation.
Findings
A case study where RP related technologies were used to support medical product development for a patient with severe injuries from a road accident is discussed.
Originality/value
The paper considers current available technologies, and discusses new advancements in direct metal freeform fabrication, and its potential to revolutionise the medical industry.
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Neal de Beer and André van der Merwe
The purpose of this paper is to develop a process chain for design and manufacture of endplates of intervertebral disc implants, with specific emphasis on designing footprint…
Abstract
Purpose
The purpose of this paper is to develop a process chain for design and manufacture of endplates of intervertebral disc implants, with specific emphasis on designing footprint profiles and matching endplate geometry.
Design/methodology/approach
Existing techniques for acquiring patient‐specific information from CT scan data was and a user‐friendly software solution was developed to facilitate pre‐surgical planning and semi‐automated design. The steps in the process chain were validated experimentally by manufacturing Ti6Al4 V endplates by means of Direct Metal Laser Sintering to match vertebrae of a cadaver and were tested for accuracy of the implant‐to‐bone fitment.
Findings
Intervertebral disc endplates were successfully designed and rapid manufactured using a biocompatible material. Accuracy within 0.37 mm was achieved. User‐friendly, semi‐automated design software offers an opportunity for surgeons to become more easily involved in the design process and speeds up the process to more accurately develop a custom‐made implant.
Research limitations/implications
This research is limited to the design and manufacture of the bone‐implant contacting interface. Other design features, such as keels which are commonly used for implant fixation as well as the functionality of the implant joint mechanics were not considered as there may be several feasible design alternatives.
Practical implications
This research may change the way that current intervertebral disc implants are designed and manufactured.
Originality/value
Apart from other areas of application (cranial, maxillofacial, hip, knee, foot) and recent research on customized disc nucleus replacement, very little work has been done to develop patient‐specific implants for the spine. This research was conducted to contribute and provide much needed progress in this area of application.
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Sameer C. Raghatate, Abhaykumar M. Kuthe, Tushar R. Deshmukh and Sandeep W. Dahake
The main purpose of this paper is to report the successful treatment modality for patients suffering from arthritis of the metatarsophalangeal joint (MTPJ) of the foot which…
Abstract
Purpose
The main purpose of this paper is to report the successful treatment modality for patients suffering from arthritis of the metatarsophalangeal joint (MTPJ) of the foot which otherwise could not be treated through traditional surgeries.
Design/methodology/approach
The unique capabilities of the computer-aided design and the rapid prototyping (RP) technology are used to develop the customized MTPJ implant (SamKu).
Findings
This approach shows good results in the fabrication of the MTPJ implant. Postoperatively, the patient experienced normalcy in the movement of the MTPJ of the foot.
Practical implications
Advanced technologies made it possible to fabricate the customized MTPJ implant (SamKu). The advantage of this approach is that the physical RP model assisted in designing the final metallic implant. It also helped in the surgical planning and the rehearsals.
Originality/value
This case report illustrates the benefits of imaging/computer-aided manufacturing/RP to develop the customized implant and serve those patients who could not be treated in the traditional way. This is a pioneered attempt toward implementation of a customized implant for patients suffering from arthritis of the MTPJ.
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Artur Swierczek and Natalia Szozda
The purpose of this paper is to explore the effects of demand planning practices on the disruptions induced by operational risk. The study reveals whether the negative…
Abstract
Purpose
The purpose of this paper is to explore the effects of demand planning practices on the disruptions induced by operational risk. The study reveals whether the negative consequences of operational risk factors (covering demand, supply, control and process risks) can be absorbed or amplified through the application of specific demand planning practices in supply chains.
Design/methodology/approach
The study involves the partial least squares path model procedure. Likewise, the items of the constructs in the outer model were subjected to a purification process by principal component analysis with the orthogonal (varimax) and oblique (Promax) methods of rotation.
Findings
The findings suggest that although one may not observe uniformity and standardization in the role of demand planning in alleviating the negative effects of operational risks, still some regularities can be obtained. Having said that some demand planning practices tend to mitigate or reinforce disruptions driven by operational risk, whereas the other practices simultaneously absorb and amplify disruptions driven by operational risk.
Practical implications
The study shows that different managerial instruments, which are not inherently dedicated to risk management, when appropriately applied, may have an indirect impact on the mitigation of supply chain risk. In particular, the concept of demand planning might be very helpful for managers when dealing with demand and control risks.
Originality/value
The study simultaneously examines a more detailed bundle of practices forming the demand planning process. The research attempts to investigate the link between the demand planning process and operational risk consequences, derived from all sources (supply, demand, process and control). The paper shows that risk management is not a sole tool to mitigate disruptions. Among the concepts, which contribute to decrease risks is the demand planning process. The study demonstrates that the demand planning process when applied as a component of supply chain management, may contribute to mitigate certain operational risks.
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T.R. Deshmukh, A.M. Kuthe, S.M. Chaware, B. Vaibhav and D.S. Ingole
The purpose of this paper was to find a successful treatment modality for patients suffering from temporomandibular joint (TMJ) ankylosis who could not be treated through…
Abstract
Purpose
The purpose of this paper was to find a successful treatment modality for patients suffering from temporomandibular joint (TMJ) ankylosis who could not be treated through traditional surgeries.
Design/methodology/approach
This work integrated the unique capabilities of the imaging technique, the rapid prototyping (RP) technology and the advanced manufacturing technique to develop the customised TMJ implant. The patient specific TMJ implant was fabricated using the computed tomography scanned data and the fused deposition modeling of RP for the TMJ surgery.
Findings
This approach showed good results in fabrication of the TMJ implant. Postoperatively, the patient experienced normalcy in the jaw movements.
Practical implications
Advanced technologies helped to fabricate the customised TMJ implant. The advantage of this approach is that the physical RP model assisted in designing the final metallic implant. It also helped in the surgical planning and the rehearsals.
Originality/value
This case report illustrates the benefits of imaging/computer‐aided design/computer‐aided manufacturing/RP to develop the customised implant and serve those patients who could not be treated in the traditional way.
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François Pérès, Farid Taha, Marie‐Antoinette de Lumley and Emmanuel Cabanis
The National Museum of Natural History has been carrying out, over the last several years, a study of hominid fossil skulls, which have been discovered in different regions of the…
Abstract
The National Museum of Natural History has been carrying out, over the last several years, a study of hominid fossil skulls, which have been discovered in different regions of the world. The aim of the palaeo‐anthropological study of these skulls is to reconstruct the genealogic tree of the evolution of man and to understand better, the diversity of the homo Erectus species on the different continents. Currently, digital techniques and those of rapid prototyping offer a solution to these problems by allowing the virtual or physical reconstitution of the skulls for scientific study. This paper presents this new perspective for the world of palaeontology.
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Ryszard Uklejewski, Mariusz Winiecki, Piotr Rogala and Janusz Mielniczuk
The aim of this paper is to present the main results of a research project finished in 2008 which concerned the selective laser melted (SLM) prototype of a new kind of minimally…
Abstract
Purpose
The aim of this paper is to present the main results of a research project finished in 2008 which concerned the selective laser melted (SLM) prototype of a new kind of minimally invasive resurfacing hip arthroplasty (RHA) endoprosthesis with the original multi‐spiked connecting scaffold (MSC‐Scaffold). Previous attempts performed in pre‐Direct Metal Manufacturing (DMM) era demonstrated that it was impossible to manufacture suitable prototypes of this RHA endoprosthesis (especially of the MSC‐Scaffold) using traditional machining technologies. Owing to an extensive development of DMM technologies observed in recent years the manufacturing of such prototypes has become possible.
Design/methodology/approach
Computer aided design models of pre‐prototypes and the prototype of the RHA endoprosthesis with MSC‐Scaffold were designed and initially optimized within the claims and the general assumptions of international patents by Rogala. Prototyping in SLM technology was subcontracted to SLM Tech Center (Paderborn, Germany). Macroscopic and SEM microscopic evaluation of the MSC‐Scaffold was performed using SLM manufactured prototypes and paying special attention to the quality and precision of manufacturing.
Findings
It was found that SLM can be successfully applied to manufacturing of prototypes of the original minimally invasive RHA endoprosthesis. The manufacturing quality of the 3D spikes system of the MSC‐Scaffold, which mimics the interdigitations of articular subchondral bone, has been proved to be geometrically corresponding to the biological original. Nevertheless, some pores and non‐melted zones were found in SLM prototyped RHA endoprosthesis cross‐sections which need to be eliminated to minimize the potential risk of clinical failure.
Research limitations/implications
The presented case study was performed with a limited number of samples. More research needs to be performed on the rapid prototyped samples including microstructural and mechanical tests. The results may enable the optimization of the SLM manufacturing process of the prototypes of the minimally invasive RHA endoprosthesis with MSC‐Scaffold.
Practical implications
The SLM can be considered as potentially suitable for the fabrication of patient‐fitted minimally invasive RHA endoprostheses with MSC‐Scaffold.
Originality/value
For the first time, largely owing to SLM technology, it was possible to manufacture the prototype of the original minimally invasive RHA endoprosthesis with MSC‐Scaffold suitable for further research.