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This paper presents a methodology of proposing a platform differentiation plan (PDP) to provide a platform leverage strategy across market niches. PDP is designed to provide a consistent balance between mutual differentiation and components sharing for the leveraged platforms at the early product planning stage. Two indices, i.e. differentiation index (DI) and commonality opportunity index (COI), are presented to represent the dimensions of product platform differentiation and commonality, respectively. Through a case study of electronic test equipment (ETE), the usefulness of PDP for the platform leverage strategy across market niches is demonstrated.

Product Lifecycle Management (PLM) is recognized as one of the most effective approaches for better, fast and cheaper product development and management. Mass customization is one of the key technologies in PLM to provide tailored product to end customers with the cost of mass production. Characterized by short production lead-time and dynamic customer requirements with low batch size and high variety, tooling product families are facing the challenge of high production cost. New technology with modular feature-based design to manufacturing collaboration to satisfy the needs of mass production with low cost in tooling industry is developed in this study. A corresponding prototype system is demonstrated to show the efficiency of the technology developed.

Driven by industrial needs and enabled by the latest information technology, enterprise integration has rapidly shifted from information integration to process integration for performance excellence in the entire business process. This paper reports on the modeling of a business information model which enables mold making companies to achieve business process integration. The needs of process integration in mold making companies are first highlighted. Typical mold making business processes are analyzed and four critical business processes to be integrated are identified. Further, a process-oriented business information model is proposed, which associates business information entities to meet the needs of all business processes. Based on the model, the integration of four critical business processes is investigated, which enables seamless information flows to streamline the business processes, maximize information sharing across the business processes and achieve the automation and concurrency of the business processes. Finally, the implementation and benefits to industry of the system derived from the developed information model is presented.

One of the challenging problems that hinder the development of distributed design systems is the contradiction of large CAD files and the limited speed to share them over the Internet and Web. 3D streaming technique, which can allow effective and efficient dispatch and access of large-volume CAD data as a series of patched streams across the Internet, provides a promising solution to overcome the obstacle. Geometric simplification (or decimation) of 3D models is a key algorithm to realize the streaming technique. In this paper, a new geometric simplification algorithm has been developed, in which two criteria are the crucial elements to control the collapse process for edges in 3D VRML models to reduce the amount of information. After the simplification and sharing of a model, a developed refinement algorithm is carried out to restore the model from its simplified version back to its original, through combining the simplified model with some reconstruction data generated during the simplification process, therefore, to realize the streaming information sharing. The major feature of the simplification algorithm is that it has incorporated some advantages of the previously developed vertex decimation approach and edge collapse approach. Meanwhile, the mechanism of adaptive threshold parameters adopted in this work enhances the adaptability of the algorithm for various applications. Through case studies and comparisons with some related works, the algorithm shows good performance and potentials in terms of effectiveness, adaptability and robustness.

Concurrently engineered product development requires effective inter-functional communication and knowledge sharing across multidisciplinary teams and heterogeneous processes. This paper presents a semantics-enabled approach to the integration of knowledge maps with design process configurations to support more meaningful communication and seamless collaboration between cross-functional teams and concurrent workflows in new product introduction (NPI) processes. The proposed approach focuses on: explicit and formalized process description and configuration of NPI activities; process knowledge capture and reuse through knowledge maps; integration of knowledge maps into design process configurations; and ontology-based process model mapping and knowledge sharing to support seamless process collaboration. It thereby contributes to the development of the next generation concurrent engineering methodologies in order to achieve NPI process advances for meaningful inter-functional communication and collaboration. The approach has been implemented in a software prototype to provide the concurrently engineered product development with the capabilities of semantic process description and configuration, knowledge reuse, and process collaboration.

With the arrival of cyber physical world and an extensive support of advanced IT infrastructure, nowadays it is possible to obtain the footprints of design activities through emails, design journals, change logs, and different forms of social data. In order to manage a more effective design process, it is essential to learn from the past and understand, for example, what design tasks are actually carried out, their interactions and how they impact each other. In this paper, a computational approach based on deep belief nets (DBN) is proposed to automatically uncover design tasks and quantify their interactions. A DBN topic modeling with real-valued units is to learn a set of intrinsic topic features from a simple word-frequency based input representation. Evaluated using a design email archive spanning for more than two years, the proposed approach has achieved a much higher accuracy in identifying design tasks compared to a prevailing approach.Copyright © 2015 by ASME

This paper presents the study of the distinctiveness of single human tooth and the development of three dimensional (3D) single-tooth identification scheme which is useful when only very partial jaws with teeth are available. Two types of single-tooth samples are studied: tooth crown segmented from scanned dental casts and entire single tooth (crown and root) reconstructed from cone beam CT images. Eigenteeth feature and K nearest neighbourhood (KNN) classifier are applied to classify posterior (molar, premolar) and anterior (canine and incisor) tooth types. The iterative closest point algorithm (ICP) is then applied to match post-mortem (PM) and ante-mortem (AM) tooth data, with the former being the sample to be matched, and the latter representing captured complete tooth geometry kept in a database.

Most companies in tooling industry position themselves as partners of large companies and operate in a made-to-order fashion. As the product lifecycle is becoming short, the time for tooling companies to design and produce tools shrinks remarkably. To survive in such a competitive market, many tooling companies are seeking solutions to shorten their entire business cycle by improving their working efficiency and productivity with effective collaboration. This paper presents a collaborative engine, capable of supporting horizontal and vertical integration by providing a computer-supported collaborative environment. The engine has been modeled and designed as a foundation for the development of collaborative environments for tooling companies to improve business performance by enhancing internal collaboration, maximizing information sharing and reuse, and seamlessly linking business activities. A collaborative design environment has been prototyped to demonstrate the efficiency of the engine.

Information availability is a key factor for business success and competitive advantage. While created by design engineers, product structure is accessed and referenced by other users involved in product lifecycle from various departments. However, there is a lack of efficient ways of managing product structure information for enterprise business process integration. This study proposes a unified product structure management model to fill in this gap. With this proposed model, the product structure is managed in a unified way and can be accessed by different people with various disciplines in the right formats throughout the entire product lifecycle, including business processes of quotation, sales order processing, design, planning, scheduling, production, and delivery. This research is part of the enterprise business information management system project whose purpose is to streamline the information management for key business processes to integrate multi-disciplines in an enterprise for product develo...

As the product market lifecycle is becoming shorter, molding companies are forced to reduce the time to market. At the same time, the pressure of time-to-market is also conveyed to mold making comp...

Often ranked at the top of the core competencies by manufacturing firms, product design & development (PDD) is indeed a series of knowledge intensive activities. It demands timely information and diverse support from various knowledge sources to help the company remain competitive. Therefore, the integration of current information and existing knowledge, either internally owned or externally located, has become increasingly important. In this paper, a framework to serve PDD personnel for better information and knowledge management purpose based on text mining (TM) methodology is proposed. Several key initiatives undertaken are explained and moreover, the encouraging results achieved in our attempt to integrate manufacturing domain knowledge in conventional TM tasks are demonstrated.

The various computer-aided systems in many small and medium sized enterprises (SMEs) work independently at present. This leads to broken information flows and fragmentized business processes, which are the main obstacles to the improvement of business performance. Application integration promotes information sharing, streamlines business processes, and motivates internal collaboration. Moreover, the integration of standalone applications can make use of existing resources and minimize impacts on the current business practices. Therefore, it is an economical approach for SMEs to integrate standalone applications for optimized business performance. This paper presents the modeling of an integrated process planning system, which is intended to assist SMEs to achieve concurrent engineering in design, process planning and manufacturing. Firstly, the integrated system architecture is proposed by addressing the generality and reusability of functional components and collaboration support. Then, a concurr...

In the modern global economy, companies are facing ever-increasing challenges for short time-to-market to enter into the market early, for reduced time-to-volume to occupy the market quickly, and for decreased time-to-profit to get return from market shortly. Product lifecycle management (PLM) is recognized as one of the key leading technologies to facilitate companies to overcome these challenges, which will offer companies a new way to rapidly plan, organize, manage, measure, and deliver new products or services much faster, better, and cheaper in an integrated way. Following this trend, this study proposes a full scenario of technology solutions for PLM based on the complete analysis of business drivers, industry requirements, limit of current solution, and recent state-of-the-art review in the domain related to PLM. Potential industrial impact of the developed PLM technology solutions is analyzed. It is hoped that the proposed PLM technology solutions will form the frontier basis for further research, development, and application of PLM systems to quickly adapt to the dynamic changing market for industry companies to pursue the most advanced competitiveness.

In order to facilitate product design and realization processes, presently, research is actively carried out for developing methodologies and technologies of collaborative computer-aided design systems to support design teams geographically dispersed based on the quickly evolving information technologies. In this paper, the developed collaborative systems, methodologies and technologies, which are organized as a horizontal or a hierarchical manner, are reviewed. Meanwhile, a 3D streaming technology, which can effectively transmit visualization information across networks for Web applications, is highlighted and the algorithms behind it are disclosed.

In order to facilitate product design and realization processes, presently, research is actively carried out for developing methodologies and technologies of collaborative computer-aided design systems to support design teams geographically dispersed based on the quickly evolving information technologies. In this paper, the developed collaborative systems, methodologies and technologies, which are organized as a horizontal or a hierarchical manner, are reviewed. Meanwhile, a 3D streaming technology, which can effectively transmit visualization information across networks for Web applications, is highlighted and the algorithms behind it are disclosed.

Due to the large variety of CAD systems in the market, data exchange between different CAD systems is indispensable. Currently, data exchange standards such as STEP and IGES, etc. provide a unique approach for interfacing among different CAD platforms. Once the feature-based CAD model created in one CAD system is input into another via data exchange standards, many of the original features and the feature-related information may not exist any longer. The identification of the design features and their further decomposition into machining features for the downstream activities from a data exchanged part model is a bottleneck in integrated product and process design and development. In this paper, the feature panorama is succinctly articulated from the viewpoint of product design and manufacturing. To facilitate feature identification and extraction, a multiple-level feature taxonomy and hierarchy is proposed based on the characteristics of part geometry and topology entities. The relationships between the features and their geometric entities are established. A litany of algorithms for the identification of design and machining features are proposed. Besides, how to recognize the intersecting features or compound features based on the featureless chunks of geometry entities is critical and the issue is addressed in the paper. A multi-level compound feature representation and recognition approach are presented. Finally, case studies are used to illustrate the validity of the approach and algorithms proposed for the identification of the features from CAD part models in neutral format.

It is known that hydrophobic microfiltration membranes can be used for demulsification of oil-in-water (o/w) emulsion due to coalescence of oil droplets in membrane pores. This study demonstrates that a hydrophilic polymer membrane can be used for the demulsification of surfactant-stabilized water-in-oil (w/o) emulsions. The success of demulsification is dependent on the type of emulsions and membrane used. Membrane pore size and transmembrane pressure were found to affect demulsification efficiency (DM), while other factors, such as membrane thickness and initial water content have slight or almost no effect. A coalescence mechanism of the demulsification phenomenon is also discussed. The separation process is not based on sieving effects due to a difference in membrane pore size, but is determined by droplet interactions with membrane surface.

Bamboo shoots grow quickly through the rapid elongation of internodes. In order to verify whether DNA methylation affects bamboo shoot elongation, we compared DNA methylation levels at five developmental stages of bamboo (Phyllostachys praecox), including young bamboo shoot of 40-cm at length (S1), bamboo shoot of 2-cm at length (S2), young leaf (Y1), leaf (Y2), and aging leaf (M), by using amplified fragment length polymorphism (AFLP) based on KpnI/MseI and Acc65I/MseI platforms. The polymorphism ratio of methylated to unmethylated DNA sites in bamboo shoot (S1 and S2) was higher than that in leaf (Y1, Y2 and M). The polymorphism ratio of methylated to unmethylated DNA sites in S2 was highest (32%). Our results suggest that DNA methylation changed greatly at bamboo growing stages, especially in stage of rapid elongation of internodes.

A process planner for three-dimension prismatic parts is developed in this paper by utilizing case-based techniques. A three-dimension prismatic part is represented by a set of primary features (such as holes, pockets, slots, etc). The subplan candidates for individual features of a part are first generated by the proposed system via a backward inference planner based on the specifications of cutting tools available in a factory. The system then combines all subplans into the final process plan for a given part based on the merging information. The merging information is the information regarding the manufacturing environment of a factory (i.e. machine layout, transfer line, etc), and plays a key role in the process planning. Generally, the merging information is contained in old plans, and will be extracted by the system using case-based techniques. This way, the proposed system can generate a practical process plan for a given part based on case histories provided by the factory itself. The proposed pro...

Tissue engineering is a multi-disciplinary area of research bringing together the fields of engineering and life sciences with the aim of fabricating tissue constructs aiding in the regeneration of damaged tissues and organs. Scaffolds play a key role in tissue engineering, acting as the templates for tissue regeneration and guiding the growth of new tissue. The use of stem cells in tissue engineering and regenerative medicine becomes indispensable, especially for applications involving successful long-term restoration of continuously self-renewing tissues, such as skin. The differentiation of stem cells is controlled by a number of cues, of which the nature of the substrate and its innate stiffness plays a vital role in stem cell fate determination. By tuning the substrate stiffness, the differentiation of stem cells can be directed to the desired lineage. Many studies on the effect of substrate stiffness on stem cell differentiation has been reported, but most of those studies are conducted with two-dimensional (2D) substrates. However, the native in vivo tissue microenvironment is three-dimensional (3D) and life science researchers are moving towards 3D cell cultures. Porous 3D scaffolds are widely used by the researchers for 3D cell culture and the properties of such scaffolds affects the cell attachment, proliferation, and differentiation. To this end, the design of porous scaffolds directly influences the stem cell fate determination. There exists a need to have 3D scaffolds with tunable stiffness for directing the differentiation of stem cells into the desired lineage. Given the limited number of biomaterials with all the desired properties, the design of the scaffolds themselves could be used to tune the matrix stiffness. This paper is an in silico study, investigating the effect of various scaffold parameter, namely fiber width, porosity, number of unit cells per layer, number of layers, and material selection, on the matrix stiffness, thereby offering a guideline for design of porous tissue engineering scaffolds with tunable matrix stiffness for directing stem cell lineage specification.

Concept validation plays a critical role in product design especially in the early design phase of market-driven product design. Due to the presence of ambiguous information, arbitrary interpretation of user needs, and so on, design concept validation remains a challenging task. In this work, we aim to involve customers in the conceptual design phase so that understanding about customer needs, expectations, and satisfaction can be better altered through customer–design interaction. A framework for concept validation using digital prototyping is proposed to actively involve customers in three major validation tasks, i.e., specification solicitation, concept selection, and concept refinement. Technical challenges of involving customers in conceptual design using digital prototyping are discussed. Our experimental study based on smartphone dimension design reveals the capabilities of the proposed framework. Experimental results suggest when interacting through digital prototyping, customer satisfaction on design concepts can be enhanced by making alterations to customer needs, expectations, and satisfaction.

In this study, polycaprolactone/mineral trioxide aggregate (PCL/MTA) scaffolds were successfully fabricated via an electrohydrodynamic jet (or E-jet) 3D printing system developed by our group. The viscosity of the composited solutions and the key process parameters (i.e. applied voltage and feed rate) were investigated to achieve an optimal process condition. To investigate the potential of PCL/MTA scaffolds to support regeneration ability for dentin related tissue, we seeded dental pulp stem cells on the scaffolds, and compared the results with cell-seeded PCL scaffolds. Assessment of cell viability and proliferation using live/dead cell staining and MTS assay showed compatibility of PCL and PCL/MTA scaffolds for cellular attachment and growth. These scaffolds could be used for fabrication of three-dimensional tissues and in future could be applied to dentin and periodontal tissue engineering applications.

The basic idea of case-based reasoning (CBR) is to retrieve and modify the most relevant prior case to match new requirements. In this paper, a framework for a process planning system for machining of axisymmetric parts using case-based reasoning is introduced. It is composed of four major components: retriever, modifier, simulator, and repairer. When a desired axisymmetric part is to be machined, the proposed system first retrieves the most relevant case from the case library as a plan candidate. Since the plan candidate is rarely the same as the desired one, the system performs modification, simulation, and reparation on it. The proposed system has been implemented on a Sun workstation using the ACIS geometric modeler and C++.

To reduce the manufacturing time of a product, one effective way to develop a machining process plan for a new part is to retrieve a relevant case of process planning similar to a new desired part and then adapt the retrieved case to meet the new requirements. This paper proposes a mechanism for retrieval of process planning cases. The core of the retrieval mechanism contains: (1) a feature-based representation of a part and cutting processes; (2) indexing of a part; (3) a feature hierarchical structure based on cutting processes; and (4) a similarity metric used to measure the similarity between a new desired part and any old part in the case base. The application domain here is for axisymmetric part machining. A prototype based on the retrieval mechanism is implemented on a Sun workstation using the ACIS 3D-Toolkit from Spatial Technology Inc.

In today's competitive business environment, a product development is the result of a team effort involving a multi-disciplinary group of designers, manufacturers, even supplier and customer representatives. Effective collaboration among various groups is impor tant for reducing cost and product development time. Hence, the aim of our study is to develop a WWW-based collaborative system for integrated design and manufacturing. The proposed system is composed of three modules—collaboration, design, and manufacturing. This paper focuses on its collaboration module and the design module. Its manufacturing module is discussed in References [1] and [2]. The collaboration module is WWW-based platform-independent and provides a virtual collaborative environment for a part designer to perform on-line communication with customers and manufacturers via the Internet. All participants in the collaborative environment can view, and manipulate the solid model of the design part as well as discuss their concerns on-line interactively. The design module utilizes the design by features approach to construct a part. Traditional design by features systems restrict the designer to a fixed set of pre defined features provided by the system vendor. The proposed design module includes an extension mechanism for designers to create user-defined features and an evaluation mechanism for designers to perform manufacturability evaluation. The design module is able to generate a very complicated user-defined feature and to provide feedback concerning potential manufacturing problems in the early design stage. Both proposed modules have been implemented on a Sun workstation using the ACIS geometric modeler, C++, and JAVA.

The problem of controlling the average resultant cutting force together with the contour error in multi-dimensional end milling operations is considered in this study. Two sets of neural networks are used in the control system. The first set is used to specify the feed rate to maintain a desired cutting force. This feed rate is resolved along the feed axes using a parametric interpolation algorithm so that the desired part shape is obtained. The second set is used to make corrections to the feed rate components specified by the parametric interpolation algorithm to minimize the contour error caused by the dynamic lag of the closed-loop servo systems controlling the feed drives. In addition, the control system includes a feedforward input to compensate for static friction effects. Experimental results are presented for machining two-dimensional circular slots and a three-dimensional spherical surface to show the validity of the proposed approach.

This paper proposed a framework for integrating artificial intelligence (AI) techniques and mechanistic models in the task of generating process plans for prismatic parts. The main issue of process planning addressed in this paper is the determination of the operation sequence for mechanical parts containing interacting features where machining of one feature might adversely affect the surface quality of other features. The informed graph-search strategy in AI is used to achieve the function of operation sequence planning. The search graph is built by considering alternative machining operations in converting a blank stock into the final part configuration. Several heuristic functions concerning machining practices are developed to help to reduce the complexity of the search graph. Mechanistic models of different interaction machining situations are also considered to help the graph-search process so that the process plan generated can ensure the machining of high-quality mechanical parts. this idea of incorporating mechanistic models in operation sequence planning activities makes it possible to build in surface-quality considerations at the early process-planning stage.

This paper presents a haptics-based training simulator for dental implant surgery. Most of the previously developed dental simulators are targeted for exploring and drilling purpose only. The penalty-based contact force models with spherical-shaped dental tools are often adopted for simplicity and computational efficiency. In contrast, our simulator is equipped with a more precise force model adapted from the Voxmap-PointShell (VPS) method to capture the essential features of the drilling procedure, with no limitations on drill shape. In addition, a real-time torque model is proposed to simulate the torque resistance in the implant insertion procedure, based on patient-specific tissue properties and implant geometry. To achieve better anatomical accuracy, our oral model is reconstructed from cone beam computed tomography (CBCT) images with a voxel-based method. To enhance the real-time response, the parallel computing power of GPUs is exploited through extra efforts in data structure design, algorithms parallelization, and graphic memory utilization. Results show that the developed system can produce appropriate force feedback at different tissue layers during pilot drilling and can create proper resistance torque responses during implant insertion.

In remanufacturing practices, understanding and communicating the failure risk and reliability of a critical part, component or subsystem plays a crucial role as it has a significant impact on the lifecycle management of the product and thus determines the success of the remanufacturing process. In this respect, statistical time-to-failure analysis provides a very powerful and versatile analytical tool for reliability analysis and risk assessment. Among various statistical tools available, Weibull model which uses time series data on records of failure incidents of a product for the fitting of a parametric distribution, is a powerful approach to characterizing the time-to-failure probability function of the product. It is able to provide valuable information for optimized lifecycle management and remanufacturing process. This paper demonstrates successful applications of Weibull model for time-to-failure analysis using case studies in remanufacturing practices and proposes a statistical approach to assess the reliability of critical parts and components for remanufacturing in the product’s lifecycle management. It is envisaged that the research results are able to benefit remanufacturing practices in many ways such as reducing warranty loss by minimizing probability of failure of remanufactured critical parts and components.

The planning of cost-effective strategies to manage products at end-of-life (EoL) is still a major challenge for manufacturers. Different methods have been developed to tackle this challenge but they have mainly approached it from a third-party remanufacturer or recycler perspective. Our work instead focuses on closed-loop supply chains where an integrated lifecycle approach to EoL planning is necessary. By applying a product structure-based methodology, we demonstrate how interrelationships between the EoL and other life cycle stages in a closed-loop supply chain can be captured during the EoL planning process. Its application is demonstrated using a dive torchlight example.

Management of products and resources at end-of-life (EoL) includes recovery of product for reuse, remanufacturing for reviving parts and component, recycling for material contents and responsible disposal. The decisions are affected greatly by the mix of product varieties, recovery technologies, economic value, social and environmental impacts. An informed EoL product recovery decision can be accomplished when recovery aspects are better integrated in design and manufacturing phase. This paper introduces an efficient returned product assessment framework for original equipment manufacturer (OEM), where the assessment refers to design and manufacturing results. However, this integration poses challenging problem of decisions subject to uncertainties. A detailed and systematic product inspection and verification approach is proposed in this paper. It guides a decision maker to solve product recovery selection problem with optimized recovery value. This method is demonstrated with returning hair dryer.

This paper presents an approach for the case adaptation, especially case repairing, in a case-based process planning system: PROCASE, for machining of rotational parts. In PROCASE, a new process plan is generated by adapting an existing similar process plan from its case library. Case adaptation is a crucial issue in achieving an automated case-based process planning system. This is because, usually, an existing process plan cannot necessarily produce an exact identical part as of the desired part. Adaptation is essential to tailor this existing plan to generate a new process plan for the new part. The case adaptation in this paper comprises case modification, case simulation, and case repairing. The modifier uses the knowledge extracted from case library to edit the retrieved similar plan. The simulator plays an important role in verifying the adapted plan as well as in directing the plan repairing. The repairing rules are indexed by the error messages obtained from the simulation. With the proposed case adaptation, the system will have the capability to repair the erroneous plans to achieve an automated and intelligent process planning system. This paper will first briefly introduce the case representation and case retrieval in PROCASE. Then the rest of the paper is dedicated to the case adaptation.

This paper addresses the methodology development for achieving one of the important functions in automated process planning: automated determination of sequence of machining operations for prismatic parts containing various types of form features. A framework of using the case-based reasoning approach to support learning capability in operation sequencing is first proposed. The methodology to accomplish various issues in case-based operation sequencing is then discussed. In particular, the following issues are considered: 1. Representation of operation sequencing cases. 2. Indexing and retrieval of operation sequencing cases. 3. Adaptation of operation sequencing cases. Finally, the implementation issues are addressed and the learning functions of the intelligent operation sequencing system are demonstrated.

The skin is the largest organ of the body, having a complex multi-layered structure and guards the underlying muscles, bones, ligaments, and internal organs. It serves as the first line of defence to any external stimuli, hence it is the most vulnerable to injury and warrants the need for rapid and reliable regeneration methods. Tissue engineered skin substitutes help overcome the limitations of traditional skin treatment methods, in terms of technology, time, and cost. While there is commendable progress in the treating of superficial wounds and injuries with skin substitutes, treatment of full-thickness injuries, especially with third or fourth degree burns, still looks murkier. Engineering multi-layer skin architecture, conforming to the native skin structure is a tougher goal to achieve with the current tissue engineering methods, if not impossible, restoring all the functions of the native skin. The testing of drugs and cosmetics is another area, where engineered skins are very much needed, with bans being imposed on product testing on animals. Given this greater need, 3D bioprinting is a promising technology that can achieve rapid and reliable production of biomimetic cellular skin substitutes, satisfying both clinical and industrial needs. This paper reviews all aspects related to the 3D bioprinting of skin, right from imaging the injury site, 3D model creation, biomaterials that are used and their suitability, types of cells and their functions, actual bioprinting technologies, along with the challenges and future prospects.

A novel 3D dental identification framework is presented. The objective is to develop a methodology to enable computer-automated matching of complex dental surfaces with possible missing regions for human identification. Thus far, there is no reported attempt at 3D dental identification given partially available dental casts or impressions. This approach overcomes a number of key hurdles in traditional 2D methods. Given the 3D digital form of a dental cast surface, the developed method will facilitate the search for the closest match in the database of digitized dental casts. A salient curvature matching algorithm (SCM) is proposed for pose estimation which includes algorithms for feature extraction, feature description and correspondence. The feature point extraction algorithm could extract more salient features and the correspondence algorithm is more robust for pose estimation compared to known works. Experimental results show 85.7% hit rate at rank-1 accuracy based on matching of 7 partial sets to a database of 100 full sets in significantly reduced retrieval time. The hit rate increases to 100% with parameter adjustment. This work aims to enable computer-aided 3D dental identification and the proposed method could be adjunctively used with the traditional 2D dental identification method, as the available dental source for identification is still primarily 2D radiographs. Limitations of the methodology and future directions in matching highly fragmented and partial dental surfaces are discussed.Copyright © 2012 by ASME

With the recommendation from ABET, each engineering student should go through a major engineering design experience and understand how to go from design specifications to a final artifact. The Department of Mechanical Engineering at the National University of Singapore (NUS) started automotive design projects including competition vehicles and proof of concept vehicles for its undergraduate students many years ago. These projects aim to provide practical engineering education to the students through vehicle design and fabrication with hands-on experience. The project lifecycle usually does not last longer than one year as it is governed by the competition and the academic cycle. With many years of experience supervising students, the best practice of guiding students learning through this engineering design project within one academic year is developed. Before each project, students will first go through training and apprenticeship. Such project usually starts with problem formulation that studies the requirements of vehicle for the competition and the resources available. The team of students will go from design specifications to a final vehicle prototype with generating alternatives, synthesizing, analyzing, fabrication, testing and evaluating. This method allows sustainability in vehicle design projects. NUS Eco-car project is used as a case study to illustrate the best practice. Our past experience showed that students trained in this project have strong practical and analytical skills and are able to manage and communicate in a team well.

This paper introduces a new discrete event system (DES) model for supervising and controlling trajectory planning tasks and robot motion using automata. This model is proposed based on a new approach, namely mask description. Masks are constructed adaptively and are modified based on the error between the original path and the planned path. The model acts in two phases, mask construction phase (MCP) and end-effecter positioning phase (E2P2). In MCP, it tries to plan a path, and in E2P2 it tries to place the end-effecter along the sequence of points on the path. The model describes a path in the Cartesian space and moves the end-effecter in the joint variable space, and therefore, MCP plans the path as accurate as Cartesian space description, and E2P2 position the robot as fast as joint space description. Results show that the proposed adaptive masking is remarkably efficient in computing.

Modern traffic prediction technologies enable real-time velocity planning of vehicles for less fuel consumption and polluting emissions by reducing the frequency of acceleration/deceleration, idle time, the number of stop, and variation of vehicle speeds. The fuel economy could be further improved if the optimal control strategy parameter could be used in the real-time velocity planning. However, it is difficult to find the optimal value of the control strategy parameter in this real-time velocity planning of vehicles. This paper aims to develop an advising system for control strategy parameters of HEVs in velocity planning. With this aim, the characteristics of the optimal control strategy parameters for various velocity profiles obtained from predictive velocity planning are studied in a parallel HEV. The optimal control strategy parameters with the effect of the average speed, stop frequency, and the traveling distance are investigated. The observed characteristics of the optimal parameters are obtained and can be used in the advising system to improve fuel economy in real-time velocity planning of HEVs.

This paper introduces a case-based process planning system PROCASE which generates new process routines through learning from existing process routines. In contrast to traditional rule-based systems, the process planning knowledge of the PROCASE is represented in terms of cases instead of production rules. The planning basically comprises case retrieving and case adaptation rather than chaining applicable rules together to form process plans. The advantages are, first, the system is cheaper to build as it saves the expense of knowledge acquisition. Second, the system is able to advance its knowledge automatically through planning practice. Third, it is robust, because the reasoning is not based on pattern matching but similarity comparison. PROCASE has three modules: the retriever, the adapter and the simulator. It is supported by a feature-based representation scheme which naturally serves as the case indices for case retrieving and adaptation. The retriever uses a similarity metric to retrieve an old case which is the most similar case, among all old ones, to the new case. The adapter is then activated to adapt the process plan of the retrieved case to fit the needs for the new case. The simulator is used to verify the feasibility of the adapted plan. PROCASE is implemented on a Silicon Graphics IRIS workstation using C++ . An example is given to demonstrate how the process routine is generated by the system proposed by the authors.

Knee osteotomy is a common surgery to realign the knee damaged on one side by arthritis. The procedure often requires the insertion of a screw implant into the patient's tibia. An experienced surgeon develops a tactile sensation to prevent screw stripping and to achieve the most favorable tightness between the bone and the screw. A haptic simulator has been designed and implemented as a training platform for novice surgeons, helping them to develop this particular sensation by practicing the procedure in a virtual environment. Patient-specific CT images were used to construct an anatomically accurate knee model. A voxel-based algorithm was developed to compute the torque response based on the property of bone tissues and the geometry of the screw. A torque feedback device was also designed and used to control the virtual screw and output proper torque resistance to the user. Evaluation of the simulator showed that the resistance torques during the insertion, tightening and stripping phase of screw insertion was effectively simulated.

Dental bone drilling is an inexact and often a blind art. Dentist risks damaging the invisible tooth roots, nerves and critical dental structures like mandibular canal and maxillary sinus. This paper presents a haptics-based jawbone drilling simulator for novice surgeons. Through the real-time training of tactile sensations based on patient-specific data, improved outcomes and faster procedures can be provided. Previously developed drilling simulators usually adopt penalty-based contact force models and often consider only spherical-shaped drill bits for simplicity and computational efficiency. In contrast, our simulator is equipped with a more precise force model, adapted from the Voxmap-PointShell (VPS) method to capture the essential features of the drilling procedure. In addition, the proposed force model can accommodate various shapes of drill bits. To achieve better anatomical accuracy, our oral model has been reconstructed from Cone Beam CT, using voxel-based method. To enhance the real-time response, the parallel computing power of Graphics Processing Units is exploited through extra efforts for data structure design, algorithms parallelization, and graphic memory utilization. Preliminary results show that the developed system can produce appropriate force feedback at different tissue layers.Copyright © 2011 by ASME

Engineering design involves a series of steps that lead to the creation of a product, a system, or a service to meet desired needs. The design and creation of innovative solutions to challenging engineering design problems require young engineers to be immersed in an education environment which challenges and nurtures the thought process and provides the necessary hands-on experience in design. There is increasing convergence in opinions that problem-based and experiential learning should be more integrated with the science-based engineering programs. Experiential learning is the key to engaging students to learn effectively. This paper describes an experiential learning experience for a group of undergraduate students in National University of Singapore (NUS) to design a competition fuel efficient vehicle. The students started with engineering design process and went through a series of steps to design, manufacture, assemble, test and compete in a specifically built prototype urban concept car for the competition with the experiential learning experience. Components of the competition vehicle, from chassis to diminutive parts, such as wheel uprights and motor mounts, have been carefully designed, properly analyzed and fabricated in a teamwork environment. The result is a futuristic fuel efficient urban concept car that won many awards in the competition. The team also took the initiative to promote eco-friendliness and raise awareness with the design of fuel efficient car to battle environmental issues like climate change, pollution, and energy crisis.Copyright © 2011 by ASME

The importance of mining patents to support product design has been recognized, because patents are the major information source to support innovation and contain novel ideas, which usually cannot be found in published academic papers. In patent text mining, a basic issue is patent classification. However, automatic patent classification is difficult. One potential cause of the difficulty is the imbalanced dataset i.e. the interested positive class is minor while uninterested negative class is major. To alleviate the problem of imbalanced dataset and improve the performance of a Support Vector Machine (SVM) classifier, this study proposes P-SMOTE, a new oversampling technique which focuses on the blank spaces along positive borderline of a SVM. The proposed technique was firstly investigated on Reuters-21578, which is a standard text classification dataset. Then, P-SMOTE was applied to a design patent document dataset. It was observed that a SVM classifier with P-SMOTE, compared to a SVM classifier only, successfully achieved better results.Copyright © 2011 by ASME

In the rapid product design and development, design rationale (DR) information is critical for designers to understand the design technology and for better knowledge reuse. The visualization of DR capture, search and retrieval systems is important in assisting designers to gain insights and benefits from the increasing DR repository, e.g. major design issues of an artifact and design alternatives to the issues. In literatures, we have observed that the current DR systems provide limited interactive guidance in helping designers to DR navigate and search. In our previous work, we have proposed an ISAL (Issue, Solution and Artifact Layer) model for DR discovery in which the DR information is mined from a large amount of archival documents using text mining techniques. In this paper, we focus on interactive user interface (UI) design for our DR retrieval system. With functions like view, search and analysis, designers are visually guided during DR searching. Using patents as our research data, the view functions enable engineering designers to intuitively navigate DR repository. Search functions support designers to retrieve relevant DR from multiple aspects and visualize the structure of relevant DRs from a holistic view. By applying analysis functions on the retrieved DR, visualization is able to suggest some useful DR insights, e.g. key components of certain issues, possible solutions of relevant issues, major issues of an artifact and technology development trend analysis, etc. Together with the function examples, we illustrate the merits of our interface design for DR search and retrieval.