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Highlights • Superstructure of integrated biorefinery in pulp and paper industry was developed. • It includes pulping, biochemical production and black liquor utilization sections. • Lignocellulosic biomass extracted from eucalyptus and bagasse are the feedstocks. • Potential of integrated biorefinery process was illustrated in three scenarios. • Integrated succinic acid and lactic acid can improve profitability. Abstract This work aims at developing sustainable processes for pulp and paper industry by integration of the biorefinery concept to an existing pulp and paper process. A systematic methodology employing a superstructure-based process synthesis approach is employed with support from computer-aided tools to determine potential pathways for a long-term sustainable growth objective. A superstructure of the multi-product biorefinery process network for the pulp and paper industry is developed. It is divided into three sub-networks, a chemical pulping section, a biochemical production section and a black liquor utilization section. Superstructure optimization is performed with the objective to maximize profit to determine optimal integrated networks for three scenarios. The obtained results provide useful insights for further development of the optimal networks as sustainable integrated biorefinery combined with pulp and paper mills. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

This research investigated the space compositions of Chernikhov’s 101 Architectural Fantasies via computer-aided simulation to interpret the relationships between architectural components and spatial organization. An algorithmic approach and a perception approach were tested. Traditional analysis emphasized the simulation of corresponding objects by perspective deconstruction methods, which might not be able to show the exactly correct spatial relationship between objects. This research adopted photogrammetry to investigate the non-orthogonal spatial construction of 3D objects in 2D pictures. Research results showed that the algorithmic approach may derive different degrees of angles of parallel or intersected objects, and that observers tend to be misled by the effect of “orthogonal assumption” in terms of their own visual experiences. This finding revealed that Chernikhov had created unreasonable descriptions of space. This result was verified by the existence of false parallel and orthogonal relationships between drawn building parts. Three tests were conducted. Observers used a reverse verification process to analyze three-dimensional objects re-built in simulation. The verification mirrored a two-way construction relationship between 2D perspective and 3D models. [Copyright &y& Elsevier]

The wide applications of CAD/CAM technologies have promoted the development and application of many advanced technologies, such as digital manufacturing, rapid prototyping, enterprise resources planning, computer integrated manufacturing, concurrent engineering, virtual reality, and mass customization. These advanced technologies all need to be supported by three-dimensional (3D) solid models of products. Most enterprises, however, still organize their production using 2D paper drawings, which makes difficulties for the application of these advanced technologies. It is needed to convert engineering paper drawings into 3D solid models for applications. Based on holo-extraction of information from paper drawings, this paper develops a systematic 3D reconstruction method, which simulates an experienced human designer''s thinking mode in transforming inaccurate outlines with inaccurate projection relationships in 2D drawings into 3D image, with the aid of Genetic Algorithms. [Copyright &y& Elsevier]

Abstract: In a recent paper (Computer Aided Geometric Design 23 (3), 243–260), Yang presented a novel kind of nonlinear and geometry driven subdivision scheme for curve interpolation. The author declared that this scheme was shape preserving when all free parameters were explicitly selected by some specific rules. In this note, we demonstrate that the author (a) ignored the consistency of the definition to straight edges, and also (b) did not give a perfect scheme and proof for the shape preserving subdivision. [Copyright &y& Elsevier]

the aim of this paper, is to propose a new reference line: the Frontozygomatic-Infraorbital Line (FZ-IOL). This reference line can guide the surgical team planning mandibular angle harmonization, based on the patient's skeletal proportion. The Frontozygomatic-Infraorbital Line has been adopted for symmetrization surgery, masculinization surgery, and in unsatisfactory results of previous orthognathic surgery. From March 2021 to December 2022, 3 patients were treated for severe facial asymmetry affecting mainly the lower third of the face. All cases were planned with the reference FZ-IOL. Patients were treated in the same center, at the Orthognathic Surgery Department of the Instituto Portugues da Face, Lisbon, Portugal. The Frontozygomatic-Infraorbital Line is designed virtually using software to reconstruct a 3D image from a digital imaging and communications in medicine (DICOM) file obtained from a cone beam computer tomography (CBCT). , connecting the two orbital rims. Then, a vertical line, the frontozygomatic line perpendicular to the IOL and passing through the outmost lateral portion of the frontozygomatic suture is drawn. The proposed line demonstrated how establishing appropriate reference lines is crucial for the success of the surgery. The selection of reference lines should be based on the patient's anatomy, the symmetrization process's complexity, and the surgery's desired outcome. The Frontozygomatic-Infraorbital Line represents an adequate reference line for managing mandibular angle lateral projection, improving lower third of the face symmetrization. [ABSTRACT FROM AUTHOR]

Although various structural optimization techniques have a sound mathematical basis, the structural robustness and practical constructability of optimal designs pose a great challenge in the manufacturing stage. This paper presents an automated novel approach stemming from structural optimization and engineering principles, where discrete members of the structurally optimized designs are driven towards optimal utilization. The developed workflow unifies topology, layout and size optimization in a single parametric platform, which subsequently outputs a ready-to-manufacture CAD skeletal model which can be manufactured either additively or by assembly. All such outputs are checked and validated for structural requirements; strength, stiffness and stability in accordance with standard codes of practice. In the implementations, first, a topology-optimal model is generated and converted to a one-pixel-wide chain model using skeletonization. Herein, this paper uses a novel efficient method to extract the skeleton by using pixel-padding near the domain borders. Secondly, a spatial frame is extracted from the skeleton for its member size and layout optimization. Finally, the CAD model is generated using constructive solid geometry trees and the structural integrity of each member is assessed to ensure structural robustness prior to manufacturing. Various examples presented in the paper showcase the validity of the presented workflow across various structural engineering applications. • A novel method for design-informed structural optimisation is developed. • Handles both additive and assembly-based manufacturing techniques. • Optimal design outputs are structurally safe, stable and adequately-stiff. • Automated ready-to-manufacture CAD model outputs improve design efficiency. [ABSTRACT FROM AUTHOR]

The Pythagorean-Hodograph curve (PH curve) is a valuable curve type extensively utilized in computer-aided geometric design and manufacturing. This paper presents an approach to approximate a planar algebraic curve within a bounding box by employing piecewise quintic PH spline curves, while maintaining G 2 smoothness of the approximating curve and preserving second-order geometric details at singularities. The bounding box encompasses all x -coordinates of key topological points, ensuring accurate representation. The paper explores the analysis of the G 2 interpolation problem for quintic PH curves with invariant convexity, transforming the quest for interpolation solutions into identifying positive roots within a set of algebraic equations. Through infinitesimal order analysis, it is established that a solution necessarily exists following adequate subdivision, laying the groundwork for practical application. Finally, the paper introduces a novel algorithm that integrates prior research to construct the approximating curve while maintaining control over the desired error levels. • Proposing a framework to G2 approximate planar algebraic curves with correct topology and certified error control. • Proposing a construction method of planar quintic PH curve with invariant convexity based on G2 interpolation. • Proposing the theoretical analysis of the existence condition of the solutions. [ABSTRACT FROM AUTHOR]

• A micro-measurement method based on the IPDA. This paper uses a low-pass filter to process the zero-mode current to obtain the characteristic components. Then, by calculating the second derivative of the filtered part, the selection of the inflection point dense area (IPDA) at the microscopic level is achieved. This physical significance of IPDA is used to effectively express the feature that the zero-mode current direction of the faulty feeder is entirely opposite to that of the healthy. • It is proposing an ultra-high-speed protection scheme for DC distribution networks. In this paper, only 20 sampling points within the IPDA are processed, and the selection of the data window length can be adjusted according to the system sampling frequency and other factors. It meets the requirements of DC distribution networks for protection speed and selectivity, and the algorithm can correctly detect faulty feeders in a high resistance state, with little influence from external factors. A flexible direct current (DC) distribution network based on modular multilevel converter (MMC), with the advantages of no phase change failure and fewer current conversion links. It has gradually become the development trend of future medium voltage distribution networks. However, when a single-pole ground fault occurs in the feeder, the converter's low inertia and weak damping characteristics lead to a fast-rising fault current with a high peak value, which is harmful to the system. In this paper, for the difficulty of accurately selecting the faulty feeder when a single-pole ground fault occurs in a radial DC distribution network, a detection method based on the zero-mode current within the inflection point dense area (IPDA) for the fluctuation characteristics of concave and convexity (FCCC) is proposed. Firstly, the zero-mode current of each feeder is processed using a low-pass filter to select the eigen-components; Then, taking second order derivatives of the eigen-components, and the IPDA is established, to find a period in micro measurement to achieve accurate direction correspondence with opposite directions; Again, the data within IPDA is normalized; the criterion is constructed by determining each feeder's FCCC. Finally, the simulation model is built by Power Systems Computer Aided Design to verify that the method can identify the faulty feeder in various situations. Compared with existing methods, the fault detection method proposed in this paper has good stability and can withstand large grounding resistances. [ABSTRACT FROM AUTHOR]

Databases of 3D CAD (computer aided design) models are often large and lacking in meaningful organisation. Effective tools for automatically searching for, categorising and comparing CAD models, therefore, have many potential applications in improving efficiency within design processes. This paper presents a novel asymmetric autoencoder model, consisting of a recursive encoder network and fully-connected decoder network, for the reproduction of CAD models through prediction of the parameters necessary to generate a 3D part design. Inputs to the autoencoder are STEP (standard for the exchange of product data) files, an ISO standard CAD model format, compatible with all major CAD software. A complete 3D model can be accurately reproduced using a STEP file, meaning that all geometric information can be used to contribute to the final encoded vector, with no loss of small detail. In a CAD model of overall size 10 × 10 × 10 units, for 90% of models, the class of an added feature is estimated with maximum error of 0.6 units, feature size with maximum error of 0.4 units and coordinate values representing position with maximum error of 0.3 units. These results demonstrate the successful encoding of complex geometric information, beyond merely the shape of the 3D object, with potential application in the design of search engine functionality. [ABSTRACT FROM AUTHOR]

Model-based systems engineering (MBSE) is an emerging methodology not only in the field of spacecraft systems engineering. The key objective is to store the whole system design in one single source of truth system model. The continuously maintained and customizable open-source MBSE tool Virtual Satellite developed by German Aerospace Center (DLR) offers a framework for storing such a system model. Since the open-source 3D computer aided design (CAD) software FreeCAD has a dedicated Virtual Satellite workbench for importing the 3D model file generated by Virtual Satellite, it is possible to export the 3D model from Virtual Satellite, apply changes to it in FreeCAD, and afterwards reimport it in Virtual Satellite. This paper presents a workflow implementation to conduct automated steady-state and transient thermal analyses using the Virtual Satellite system model as a basis, utilizing the aforementioned features. Part of this effort was to extend Virtual Satellite by thermal modeling capabilities, such as material parameters, surface characteristics, thermal interfaces, boundary conditions and further relevant aspects. With custom Java applications, so-called "Apps", all aspects of the system model relevant for a thermal analysis are exported from Virtual Satellite and written to accordingly generated text files. Moreover, the before described 3D model export is used to export the model to FreeCAD. The FreeCAD Python console, in combination with the finite element method (FEM) workbench, is used to create a script that executes meshing, application of the boundary and initial conditions, as well as identification of contacts between parts and application of the specified contact conductance values. The obtained files form a complete thermal model and can be fed directly into the open-source FEM software CalculiX for executing the thermal analysis. Then, the result can be processed by an additional Virtual Satellite App. To account for the space thermal environment an additional feature was added to the FreeCAD script. The feature uses orbit information obtained from external mission analysis tools to calculate the approximate combined heat load from Sun, Earth infrared, and albedo radiation at each time point in the specified simulation time interval. This new workflow allows to execute quick thermal analyses at an early design stage and therefore opens new opportunities in the evaluation of different system designs, as early as in a concurrent engineering study. Configuration parameters are provided that also allow more sophisticated analyses in later development phases, such as custom mesh definition and local mesh refinement. • Thermal design process of spacecraft relies on engineer's experience in early stages. • Potential help for the thermal design process is thermal simulation. • Thermal simulations require significant manual setup effort. • Created workflow automates simulation setup and result feedback. • Data for simulation setup maintained in MBSE system model. [ABSTRACT FROM AUTHOR]

Regolith sampling is one of the core missions in deep space exploration. The design, optimization, and fabrication of samplers are challenging tasks to meet the requirements of deep space exploration, often necessitating complex modeling with computer-aided design tools and demanding the expertise of experienced space engineers with lengthy design iterations. We propose an interactive design framework where designers collaborate with optimization tool to streamline the design process. With the operator adjusting the design goals, we introduce Bayesian optimization to automatically suggest the next sets of parameters to explore. This approach is suitable for optimization scenarios when the design goals cannot be well established as analytical functions and fewer design iterations are required. In this paper, we design and optimize the core structure of the sampler under both stress analysis and discrete element analysis, considering lower stress, greater sampling volume per unit power consumption, and smaller size. Both simulation and physical experimental results show that the design proposed by our framework outperforms existing designs with a small number of design iterations. [Display omitted] • A computational design framework for searching forms of planetary regolith samplers. • The introduction of Bayesian optimization to reduce the cost in optimizing the shape in terms of efficient interaction with granular material. • Simulation and physical experiments to validate the proposed design from our framework. [ABSTRACT FROM AUTHOR]

Raw point clouds captured by sensing devices are often contaminated with noise, which perturbs the fidelity of the original geometric information. Point cloud denoising is therefore an inseparable post-processing step, aiming to remove the noise in the point clouds. Existing point cloud denoising approaches are typically trained on datasets that have uniform point distributions and densities, making them unsuitable for effectively denoising point clouds with severe noise or irregular point distributions. In this paper, we introduce a novel random screening-based feature aggregation method for point cloud denoising. Our key insight is that merging features of dense and sparse points assists with enhancing the quality of point cloud denoising results. In specific, our approach involves randomly screening the features of local point patches and fusing richer geometric information of denser points into sparser point representations. Comprehensive experiments demonstrate that our method achieves state-of-the-art performance in the point cloud denoising task on both synthetic and real-world datasets. [Display omitted] • Random screening-based point feature aggregation is useful for point cloud denoising. • Merging features of dense points into sparser points boosts point cloud denoising. • Our pipeline demonstrates robustness to noise and saves processing time. • Our technique achieves impressive results on severe noise and irregular points. [ABSTRACT FROM AUTHOR]

This paper presents a method to decompose an op-amp into its functional blocks. The method is able to recognize functional blocks on a high level of abstraction, such as loads or amplification stages, which have a large set of possible structural implementations. The paper presents a hierarchical library of functional blocks. With increasing hierarchy levels, the structural representation of the functional blocks becomes more variable while its function emerges. We use the hierarchical order to automatically compute the functional decomposition of an op-amp given as a flat netlist. Experimental results illustrate the method. The functional block decomposition enables a comprehensive formalization of design knowledge for computer-aided design of op-amps. An overview is given how the method is applicable to circuit sizing and structural synthesis of op-amps. • New structural analysis method for analog circuits able to decompose whole op-amp topologies into their functional blocks. • A computer-oriented description for each functional block in an op-amp is presented. • Algorithms use the computer-oriented descriptions for automatic recognition. • Two applications for the structural analysis method are presented: circuit sizing and structural synthesis. [ABSTRACT FROM AUTHOR]

Creation of road and railway routes in general and also design of vertical alignment in particular constitute an significant engineering problem. The vertical alignment of roads, and especially of railways, is of great importance for passenger comfort under high-speed driving conditions. This requires alignment smoothness to a greater extent. In practice, the dominant tendency is to consider vertical arcs as parabolic curves (quadratic or cubic). Other solutions have been also proposed and analyzed in the literature, thus providing an alternative approach to traditional methods. This paper describes a design method of vertical arcs using the so-called general transition curves. These curves describe the entire curvilinear transition between two straight lines using a single equation, and the curvature at the contact points with the straight lines is zero, which is of great practical significance in the light of vehicle motion dynamics. As a result, relevant research shows that general transition curves, compared to other curves, provide a more favorable distribution of lateral changes of acceleration. The paper deals not only with appropriate design procedures of a general nature, but also specific procedures of fitting vertical arcs to preset points. The methods for designing vertical arcs constitute a useful extension of available methods, and offer a valuable tool for engineers and designers of road and railway routes. • a new approach to the design of vertical arcs was presented • the proposed approach is based on the use of so-called general transition curves • these curves are the original design tool and describe the entire transition between two straight lines with one equation • the proposed approach is algorithmic and can be very useful in computer-aided design [ABSTRACT FROM AUTHOR]

The purpose of this work was to establish an approach to drive the development, at pace, of a commercially relevant Spherical Tokamak Concept. Building on the table of parameters and idealised geometry generated from the work of S. Muldrew et al. [1] , applying core principles, tools, and approaches. The generation and utilisation of a reflective 3D Spatial Model to represent the current concept, now forms a strong basis for identifying, evaluating, and delivering future integrated decisions, developed within a 16 Month timeframe. STEP is an ambitious programme, tasked with delivering a prototype plant by 2040 as a pathway to commercial fusion energy. Tackling the integration of a system that itself is based on emergent technologies, significant assumptions (e.g. Plasma Physics) and uncertainties is a significant challenge whilst maintaining acceptable levels of commercial relevance and feasibility. This paper shares the developments and approaches to collaboration and communication taken, including the management of a graphical representation (CAD or Computer Aided Design) to overcome this challenge. The work conducted has resulted in a single point CAD (utilising CATIA software) model representing the current integration status including an appropriate approach to configuration management. Clear channels and methods of communication nurtured a successful collaborative and cross-functional integration approach. Transitioning swiftly from an externally driven approach to integration, to an inherent, self-orchestrating one across all system areas. This paper presents results as a single point Concept Design for the Integrated Tokamak, a strategic management approach, technological integration challenges (e.g. Services, Maintenance, Neutronics) faced, and considerations for the future (post concept design). Introducing a centralised design process, appropriate control and clear communication utilising CAD has been the key to maturing the STEP Tokamak Concept. Initial focus on facilitating collaboration and utilising this environment as a 'sandbox' enabled early establishment of a 'space-claim' concept design in which to iterate. Staging the integration approach and CAD model fidelity developments through 'Identification, Realisation and Accommodation' built a resilient foundation to progress through the full design process. This approach has enabled early identification of not only where the integration challenges lay but also their significance, resulting in strategic deployment of valuable resource. [ABSTRACT FROM AUTHOR]

Folding a thin sheet material such as paper along curves creates a developable surface composed of ruled surface patches. When using such surfaces in design, designers often repeat a process of folding along curves drawn on a sheet and checking the folded shape. Although several methods for constructing such shapes on a computer have been proposed, it is still difficult to check the folded shapes instantly from the crease patterns. In this paper, we propose a simple method that approximately realizes a simulation of curved folds with a triangular mesh from its crease pattern. The proposed method first approximates curves in a crease pattern with polylines and then generates a triangular mesh. In order to construct the discretized developable surface, the edges in the mesh are rearranged so that they align with the estimated rulings. The proposed method is characterized by its simplicity and is implemented on an existing origami simulator that runs in a web browser. [Display omitted] • A method to simulate curved folds with an estimated ruling arrangement is proposed. • The results are similar to actual folded paper with various crease patterns. • The proposed method has advantages in mesh size, simulation cost and robustness. [ABSTRACT FROM AUTHOR]

Computer-Aided Design (CAD) and Computer-Aided Engineering (CAE) are two of the essential tools to design and develop new products. CAD systems help to design a new product efficiently, whereas CAE systems are used to predict and assess the future functionalities (durability, structural strength, etc.) of a product. Usually, these two systems work independently; however, their mutual dependency is a topic of interest for the researchers. This paper discusses the contemporary research efforts in the domain of CAD to CAE integration and later find the research gap. Based on the research gap this paper develop a methodology to integrate a CAD to CAE systems where scientific data format HDF (Hierarchical Data Format) acts as a bridge to link the gap between a CAD and CAE system. The virtual prototype of a product is getting accurate with the advancement of CAD systems; hence, the transferability of those models to a CAE system has become more sophisticated using traditional (e.g.,.step,.iges files) methodologies. Since HDF is often used to handle massive and complex datasets for various research domains; hence, in this research effort HDF acts as a data repository neutral system to interact with the CAD and CAE systems. Based on the comprehensive literature review, this research effort aims to develop an uninterrupted integrated platform to handle complex design and analysis models using a big open-source data handling platform HDF (Hierarchical Data Format). MATLAB is used to bridge from the CAD system to HDF primarily and later from the HDF to CAE. A simple case study of analyzing a classic fluid mixing elbow demonstrates the preliminary implementation effort towards the proposed HDF-based integrated platform. [ABSTRACT FROM AUTHOR]

This paper formulates quadrilateral elements for the NURBS-enhanced finite element method (NEFEM). The objective is to extend the application of NEFEM to problems where the use of quadrilateral elements is preferred. By leveraging a mapping, between reference and physical spaces, that encapsulates the exact boundary representation of the domain, a tight integration with computer aided design (CAD) systems is achieved. The contribution of this work is an enhanced quadrilateral finite element that incorporates the exact CAD geometry purely from the boundary representation (B-rep) from CAD and without the need for a whole volume representation (V-rep) as a NURBS entity. Numerical examples involving heat transfer and linear elastic problems are used to numerically demonstrate the optimal convergence properties of the method under mesh refinement. [Display omitted] • This paper aims to reduce the gap between CAD and analysis. • A new NEFEM bilinear superparametric element is presented. • The shape functions are redesigned and solely reside in the parametric space. • Heat transfer and elasticity problems show that NEFEM achieves higher accuracy. [ABSTRACT FROM AUTHOR]

The general computer-aided interaction design method has the problem of fuzzy user experience characteristics, which leads to the low identification frame number. A computer-aided interaction design method based on virtual reality technology is designed. Through the input of visual computer for communication, the feedback structure of computer vision can be obtained, the contour diagram of human body can be connected, the user experience characteristics can be extracted by using virtual reality technology, the time of reading and generating relevant information can be read, and the computer-aided interaction mode can be constructed. Experimental results: The average number of frames identified by the computer-aided interaction method in this paper is about 81 (fps), 74 (fps) and 72 (fps), respectively, compared with the other two computer-aided interaction methods, indicating that the computer-aided interaction design method integrated with virtual reality technology has higher performance. [ABSTRACT FROM AUTHOR]

The increasing complexity in product development and the lack of knowledge exchange, for example, between development and manufacturing lead to unnecessary iteration loops and high costs. To overcome this situation, an option is the execution of a design review using multi-agent systems to provide designers with a digital assistance system for checking their CAD (computer-aided design) models regarding manufacturability using a milling process. This paper explores how to increase the scalability and robustness of multi-agent systems (MAS) for manufacturability assessment by using runtime-generated BDI (belief-desire-intention) agents and graph-based feature recognition. The applicability and validation of the presented approach is carried out by evaluating different milled part designs. [ABSTRACT FROM AUTHOR]

This paper reports a new three-dimensional (3D)-printed osteotomy guidance system to assist thoracolumbar kyphosis osteotomy and describe the guide plate design, surgical procedure, and short-term clinical results. The computer-aided design software reconstructs the 3D model of the spinal deformity region using the computed tomography data of the patient and plans the correction angle according to the deformity. The guide plate design described in previous experimental studies was used and optimized before clinical application. The lamina positioning, lamina osteotomy, and vertebral osteotomy guides were designed, and three 3D guides with different functions were used to assist osteotomy. Seven patients successfully underwent osteotomy under the guidance of a 3D guide plate. Kyphosis was corrected to different degrees without serious complications. At the last follow-up, the back pain and nerve function of 7 patients were improved to varying degrees and the internal fixation without displacement and fracture. The preliminary clinical application of the new 3D osteotomy guidance system shows that it provides an effective connection between the guide plates and a clinically operative visual field. The use of a 3D guide plate system for positioning and guidance is helpful to complete preoperative planning of anterior and middle column vertebral body osteotomy. However, the efficacy of this method should be compared to that of the free-hand technique with long-term follow-up. [ABSTRACT FROM AUTHOR]

In mechanical engineering, designers have to review a designed artefact iteratively with different domain experts, e.g. from manufacturing, to avoid later changes and find a robust, optimized design. To support the designer, knowledge-based engineering offers a set of approaches and techniques that formalize and implement engineering knowledge into generic product models or decision support systems. An implementation which satisfies especially the concurrent nature of today's design processes and allow for multi-objective decision-making is multi-agent systems. Such systems consist of entities that are capable of autonomous action, interact intelligently with their environment, communicate and collaborate. In this paper, such a multi-agent system is discussed as extension for a computer-aided design software where the agents take the role of domain experts, like e.g. manufacturing technologists and make suggestions for the optimization of the design of mechanical engineering parts. A focal point is set on the collaboration concept of the single agents. Therefore, the paper proposes the use of an action-item-list as central information and knowledge sharing platform. [ABSTRACT FROM AUTHOR]

Chemical industry is continuously looking for opportunities to manufacture the necessary commodity chemicals as well as to convert them into higher value-added chemicals-based products. Development of these chemicals-based products involves not only their design and/or selection but also their sustainable manufacturing through an appropriate chemical process, its marketing and its disposal as waste. This perspective paper considers mainly computer-aided methods and tools suitable for chemicals-based product development. The advantage of computer-aided design methods and tools is that it is possible to quickly identify promising candidates that can be further investigated and verified through focused experiment-based techniques to obtain the final optimal design. The disadvantage of using these models and/or data-based approaches is that their application ranges are limited to the available models, data and knowledge related to the currently known products. Another complexity that needs to be considered is the multiscale and multidisciplinary nature of chemicals-based product design problems. Therefore, to find new and innovative chemicals-based products, systematic computer-aided methods and tools, capable of managing this complexity are needed. In this paper, the frontiers of model and/or data-based methods for systematic chemical product design and application are presented. Various computer-aided design methods and tools including experiment-based, knowledge-based, rule-based and model-based approaches are briefly reviewed. Perspectives including challenges and opportunities in computer-aided chemicals-based product design are discussed. [ABSTRACT FROM AUTHOR]

The purpose of this review was to assess the available literature regarding bonding between current adhesive systems and computer-aided design/computer-aided manufacturing (CAD/CAM) indirect resin materials, to provide clinicians with a comparative overview of the relevant bonding procedures. An electronic search was performed through PubMed based on the keywords CAD/CAM and dental bonding. Additional relevant literature was obtained from the citations in the articles. A total of 313 papers were identified, of which 281 were excluded as being unsuitable, and an additional 3 papers were identified, giving a total of 32 articles that are included in this review. Based on this survey, it is recommended that microretentive surfaces should be generated by either blasting or hydrofluoric acid etching. This initial process should be followed by silanization to ensure chemical adhesion prior to bonding to CAD/CAM indirect resin composite materials (including Lava Ultimet, KATANA AVENCIA block, Gradia Block, Cerasmart, Paradigm, and Block HC) and CAD/CAM polymer-infiltrated ceramics (such as Vita Enamic). The use of materials containing methyl methacrylate (MMA) also appears to improve the bonding of CAD/CAM poly(methyl methacrylate) (PMMA) resin materials (including XHIPC-CAD/CAM, artBloc Temp, and Telio). [ABSTRACT FROM AUTHOR]

The proliferation of high-immersion technologies might change the way virtual prototypes are used in the design process. This paper investigates the effect of immersion on reviews – critical design situations where many decisions are made. More specifically, the paper analyses the effect of immersion on spatial (intrinsic or extrinsic) and design space (problem or solution) aspects of the review. The effects have been tested in an experimental study comparing low- (computer screen) and high- (head-mounted display) immersion collaborative virtual environments (CVEs). In the experiment, four-member distributed teams conducted early-phase reviews with virtual prototypes represented in one of the two environments. Results show that the high-immersion CVE did not significantly affect the number of feedback items. Next, there was a non-significant but medium effect on the number of extrinsic feedback items, i.e., items that consider relations between the design and surroundings (e.g., users, environment). Finally, there was a significantly higher number and proportion of problem-related feedback items. Therefore, a high-immersion CVE might be more suitable if designers would like to get more problem-related or extrinsic feedback – essential aspects for the early design phases. These findings suggest that low-immersion and high-immersion CVEs are not substitutable but rather complementary technologies. [ABSTRACT FROM AUTHOR]

This paper proposes, implements, and evaluates a reinforcement learning (RL)-based computational framework for automatic mesh generation. Mesh generation plays a fundamental role in numerical simulations in the area of computer aided design and engineering (CAD/E). It is identified as one of the critical issues in the NASA CFD Vision 2030 Study. Existing mesh generation methods suffer from high computational complexity, low mesh quality in complex geometries, and speed limitations. These methods and tools, including commercial software packages, are typically semiautomatic and they need inputs or help from human experts. By formulating the mesh generation as a Markov decision process (MDP) problem, we are able to use a state-of-the-art reinforcement learning (RL) algorithm called "soft actor-critic" to automatically learn from trials the policy of actions for mesh generation. The implementation of this RL algorithm for mesh generation allows us to build a fully automatic mesh generation system without human intervention and any extra clean-up operations, which fills the gap in the existing mesh generation tools. In the experiments to compare with two representative commercial software packages, our system demonstrates promising performance with respect to scalability, generalizability, and effectiveness. [ABSTRACT FROM AUTHOR]

Developable surfaces are widely used in Computer-Aided Design (CAD), computer graphics, architecture geometry and manufacturing. In this paper, we present an approach to segmentation and approximation of an input triangular mesh with developable patches. First, exact developable regions are detected and extracted from the input mesh. Then the non-developable region is further segmented and approximated also by developable patches. The parametric equations for all obtained developable patches are simultaneously computed, whose iso-parameter curves can serve directly as the milling paths in CNC machining. Examples and comparisons with existing works are provided. [Display omitted] • A novel method for segmenting and approximating an input mesh with developable patches is proposed. • The exact parametric equations for all segment patches are computed. • A new linearity and smoothness measures to detect curve-like features on Gauss Images is provided. [ABSTRACT FROM AUTHOR]

Over the last half century, the main application of Brain–Computer Interfaces (BCIs) has been controlling wheelchairs and neuroprostheses, or generating text or commands for people with restricted mobility. There has been very limited attention in the field to applications for computer-aided design (CAD), especially in the built environment, despite the potential of BCIs to provide a new form of environmental interaction. This paper introduces Neuron, a BCI tool that enables designers with little experience in neuroscience or computer programming to: (1) gain access to neurological data, along with established metrics relevant to design; (2) create BCI interaction prototypes, both with digital on-screen objects and physical devices; and (3) evaluate designs based on neurological information and record measurements for further analysis. After detailing the BCI tool's development, the article showcases its capabilities through two case studies within the architectural design and built environment, followed by an evaluation of the tool's performance and a discussion of its implications, limitations, and areas for future improvement. • A BCI software tool was developed for EEG data acquisition, signal processing, feature extraction, and visualization. • NEURON enables brain-controlled generative design process • NEURON enables BCI prototyping for intelligence control system with visual programming • NEURON provides an accessible platform for integrating BCI into design, promoting interdisciplinary research and practical applications [ABSTRACT FROM AUTHOR]

Optimizing heterogeneous elastic material distribution on a 3D part to achieve desired deformation behavior is an important task in computer-aided design and additive manufacturing. This paper presents a solution to this problem, which involves interactive design, automatic deformation generation, and optimization of spatial distribution of heterogeneous elastic materials. Our method improves previous techniques in three aspects. First, we incorporates a geometric deformation-based interactive design into FEM-based optimization, which makes the solution less dependent of initial guesses of Young's modulus values and it more likely to produce the target design even with sparse user input of displacements and forces at a limited set of mesh vertices. Second, we formulate the problem as an L 2 - or L 0 -optimization problem. The L 2 formulation outputs smoothly varying heterogeneous material distribution that accommodates multiple functions within a single part. The L 0 formulation achieves the computation of sparse material distribution in one step, which is beneficial for additive manufacturing with multi-material printers. Third, we utilize the adjoint method to derive formulae for efficiently computing the gradient of the objective functions, making it possible to quickly solve the optimization problem in the full-dimensional space of materials, which was previously infeasible. The experiments demonstrate the robustness and efficiency of our approach. • A geometric deformation-based design is incorporated into the FEM-based optimization. • An L0-formulation is proposed for determining the material distribution from a given set of base materials. • The adjoint method is used to derive formulae for efficient gradient evaluation. [Display omitted] [ABSTRACT FROM AUTHOR]

FinFET technology has become an attractive candidate for high-performance and power-efficient applications. In the other hand, the behavior of FinFET devices is influenced by self-heating effect (SHE) due to its 3D structure, low thermal coupling and quantum confinement effect, among others. SHE degrades the device's performance and could worsen reliability mechanisms like NBTI. In addition, some hard-to-detect open defects in FinFET based-circuits using logic gates designed with multi-fin and multi-finger techniques may escape the test and present abnormal static currents, which may increase the impact of self-heating effect and make the NBTI degradation more severe. Hence, it is crucial to accurately determine the temperature profiles of those chips passing the test and presenting abnormal static currents. This paper investigates the reliability of chips passing the test with abnormal static currents using Sentaurus Technology Computer-Aided Design (TCAD). FinFET transistors are calibrated with Intel 14-nm FinFET technology. Our TCAD simulation framework determines accurately the temperature and NBTI degradation. Using the TCAD information, the device degradation over time can be predicted. Moreover, the delay penalization of a critical logic path of an ISCAS benchmark circuit is investigated. The delay penalization of logic paths, attributed to the defect and NBTI, is analyzed with varying logic depths, emphasizing the importance of addressing critical paths with different logic depths. Our study leads to new considerations for improving the prediction of circuit reliability and taking countermeasures. [ABSTRACT FROM AUTHOR]

Vision-Based Tactile Sensors (VBTS) play a key role in enhancing the accuracy and efficiency of machining operations in robotic-assisted precision machining systems. Equipped with VBTS, these systems offer contact-based measurements, which are essential in machining accurate components for industries such as aerospace, automotive, medical devices, and electronics. This paper presents a novel approach to virtual prototyping of VBTS, specifically in perpendicularity measurements using Computer-Aided Design (CAD) generation of VBTS designs, Finite Element Analysis (FEA) simulations, and Sim2Real deep learning to achieve VBTS with high precision measurements. The virtual prototyping approach enables an understanding of the contact between VBTS with different designs and machined surfaces in terms of contact module shape, thickness, markers' density. Additive manufacturing was employed to fabricate the molds of VBTS contact module, followed by experimental validation of the robotic arm to confirm the effectiveness of the optimized VBTS design. The results show that deviation from the hemispherical shape reduces the data quality captured by the camera, hence increasing the prediction errors. Additionally, reducing the thickness of the contact module enhances the precision of perpendicularity measurements. Importantly increasing markers' distribution density significantly enhances the accuracy of up to 92 markers at which above it the rate of improvement becomes less pronounced. An VBTS with height of 20 mm, thickness of 2 mm, and 169 markers was found to be within the stringent perpendicularity standards of the aerospace manufacturing industry of 0. 5 8 ∘ as a root mean square error, and 1. 64 ° as a max absolute error around the roll and pitch axis of rotation. The established virtual prototyping methodology can be transferred to a wide variety of elastomer-based sensors. • Establishment of parametric virtual prototyping for vision-based tactile sensors for perpendicularity measurements. • Methods, namely: CAD generation, FEA simulation, Sim2Real gap bridging, and practical implementation. • Constructed the relationship between sensor design and accuracy, achieving optimization. • Practical robotic implementation and validation of the optimized sensor show only 0.58 degrees error. [Display omitted] [ABSTRACT FROM AUTHOR]

Various methods have been developed for automated and semi-automated architecture generation in the computer aided ship design processes. The question remains as to how this can speed up the design process without losing the requirement elucidation intent for concept phase. This paper presents a novel approach with a software toolset to develop design and analysis approaches to early stage ship design and provide a sketching tool. This was done by enhancing the user interface and experience of the UCL Network Block Approach to achieve a "thinking sketch" in a way that is "quick" and "fluid" enough to promote inventive and creative sketching comparable to hand sketching. The UCL Network Block Approach draws on the UCL Design Building Block (DBB) approach and uses network methods applied to the synthesis of distributed ship service systems (DS3) and Computer Aided Ship Design (CASD) to expand DS3 definition in early stage ship design. The UCL originated inside-out/DBB approach to sketch driven synthesis has been made translatable to both DBB ship descriptions and ensuring early stage naval architectural "balance". The proposed approach has been used for the first time successfully to not only carry out a rapid sketching exercise for a naval ship design but also enable quick preliminary analysis of a set of DS3 networks. • The proposed approach enabled rapid sketching exercises and analysis of ship systems in a concept warship design study. • Sketching directly on the computer gave advantages and enabled a quick system network analysis in early stage of ship design. • The proposed approach could be applied to any capable ship design software that can facilitate its philosophy. [ABSTRACT FROM AUTHOR]

The aim of this study was to review and compare the complications of mandibular reconstruction using the fibula or iliac crest flap. PubMed, Embase, and the Cochrane Library were systematically searched for available papers published up to May 2020. The primary outcomes were the number of failures, the number of patients with major donor site complications, and the number of patients with recipient site complications. Eighteen studies involving 942 patients were included (one randomized controlled trial, 12 cohort studies, and five case series). There was no difference between the fibula flap and the iliac crest flap regarding the odds ratio of failure (P = 0.563), donor site complications (P = 0.756), or recipient site complications (P = 0.452). There was no difference in the dental outcomes between the two flaps (P = 0.296). The sensitivity analyses suggest that the meta-analyses were robust. There was no publication bias. This meta-analysis suggests no difference between the fibula flap and the iliac crest flap regarding the odds ratios of failure, donor site complications, recipient site complications, and dental outcomes. The recent development of computer-aided design, 3D printing, and other technologies could optimize the surgical design, improve the success rate of the surgery, and reduce complications. Nevertheless, all non-randomized studies will be at a relatively high risk of bias. Therefore, caution should be exercised when interpreting the results of the analyses. [ABSTRACT FROM AUTHOR]

The electromagnetic field distribution as well as the resonating frequency of various modes in superconducting cavities used in particle accelerators for example is sensitive to small geometry deformations. The occurring variations are motivated by measurements of an available set of resonators from which we propose to extract a small number of relevant and independent deformations by using a truncated Karhunen–Loève expansion. The random deformations are used in an expressive uncertainty quantification workflow to determine the sensitivity of the eigenmodes. For the propagation of uncertainty, a stochastic collocation method based on sparse grids is employed. It requires the repeated solution of Maxwell's eigenvalue problem at predefined collocation points, i.e., for cavities with perturbed geometry. The main contribution of the paper is ensuring the consistency of the solution, i.e., matching the eigenpairs, among the various eigenvalue problems at the stochastic collocation points. To this end, a classical eigenvalue tracking technique is proposed that is based on homotopies between collocation points and a Newton-based eigenvalue solver. The approach can be efficiently parallelized while tracking the eigenpairs. In this paper, we propose the application of isogeometric analysis since it allows for the exact description of the geometrical domains with respect to common computer-aided design kernels, for a straightforward and convenient way of handling geometrical variations and smooth solutions. [ABSTRACT FROM AUTHOR]

Abstract Shape grammars are a generative formalism in which dynamic changes to shape structure plays a vital role. Such changes support ambiguity and emergence, and as a result shape grammars are often used as the basis for proposed developments in supporting shape exploration in computer-aided design. However, the general implementation of shape grammars remains an unsolved problem, and a common solution is to adopt a fixed structure. This paper explores the consequences of assuming a fixed shape structure, via analysis of a simple shape grammar, often used as a benchmark problem to illustrate advances in shape grammar implementation. With reference to the combinatorics of words, it is proved that adopting a finite fixed structure limits the capability of a shape grammar. The paper concludes with a discussion exploring the implications of this result for shape grammar implementation and for design descriptions in CAD. Highlights • A series of simple shape grammars are analysed according to fixed part strucutres. • It is shown that symmetric embedded lines result in periodic palindromic structures. • It is shown that these structures can limit the application of shape rules. • Implications for shape grammar implementation, and CAD in general, are discussed. [ABSTRACT FROM AUTHOR]

Abstract This paper applies the topology optimization (TO) technique to the design of custom compression casts/braces on two-manifold mesh surfaces. Conventional braces or casts, usually made of plaster or fiberglass, have the drawbacks of being heavy and unventilated to wear. To reduce the weight and improve the performance of a custom brace, TO methods are adopted to optimize the geometry of the brace in the three-dimensional (3D) space, but they are computationally expensive. Based on our observation that the brace has a much smaller thickness compared to other dimensions and the applied loads are normal forces, this paper presents a novel TO method based on thin plate elements on the two-dimensional manifold (2-manifold) surfaces instead of 3D solid elements. Our working pipeline starts from a 3D scan of a human body represented by a 2-manifold mesh surface, which is the base design domain for the custom brace. Similar to the concept of isoparametric representation, the 3D design domain is mapped onto a two-dimensional (2D) parametric domain. An Finite Element Analysis (FEA) with bending moments is performed on the parameterized 2D design domain, and the Solid Isotropic Material with Penalization (SIMP) method is applied to optimize the pattern in the parametric domain. After the optimized cast/brace is obtained on the 2-manifold mesh surface, a solid model is generated by our design interface and then sent to a 3D printer for fabrication. Compared with the optimization method with solid elements, our method is more efficient and controllable due to the high efficiency of solving FEA in the 2D domain. [ABSTRACT FROM AUTHOR]

Abstract Computer-aided fault detection for sucker rod pump is a crucial technology to monitor wells in the oil production. According to the detection results, engineers could take corresponding measures to ensure wells operating in a safe and productive state. Generally, the conventional approaches to address this problem are mainly based on dynamometer cards, but these methods have obvious defects in security risks and high maintenance cost in the application. Noteworthy, the motor is the energy resource of sucker rod pump and the change of motor's power could reflect the variation of the working states. Therefore, in this paper, a novel method based on motor power for detecting the working state of the sucker rod pump is proposed. In this method, a set of the labeled motor power curve is essential. To obtain this vital information resource, the motor power curves are labeled by transforming them into dynamometer cards, which fully consider many crucial factors in this process. Moreover, to obtain useful information from motor power data, eight novel features are defined by analyzing the mechanism of motor work and the data distribution of the curve. Subsequently, the hidden Markov model (HMM), a probabilistic model with the double stochastic process, is employed to map the relationships between motor power data and working states. At last, the proposed method is verified experimentally using an oil dataset collected from oil field including six different working states, and then this technique is compared with some other methods. In the comparison, the proposed method gives 91.7% correct diagnosis that is higher than the 72.9% of SVM and the 62.5% of ANN. The experimental results show that the performance using the method proposed in this paper is satisfactory. [ABSTRACT FROM AUTHOR]

Abstract Building Information Modeling (BIM) initially emerged as a capability to transfer information and allow interaction or interoperability of various software tools used for architectural, structural, mechanical, electrical design, and building construction. Its application from developing 3D models, structural analysis, cost estimation, and mechanical analysis has now expanded to other applications such as energy simulation. Multiple computer-aided design (CAD) tools work as BIM authoring tools to generate BIM files in different formats containing various types of building information. In addition, there are various building energy modeling (BEM) tools capable of importing these BIM files to perform energy simulation. However, such tools have various capabilities and limitations and need to be investigated and categorized in order to facilitate choosing a proper tool for design professionals in different phases of project and purposes. In addition, interoperability and data exchange issues between BIM and BEM tools should be understood in order to find solutions such as developing proper corrective middleware tools to rectify them. This paper reviews the challenges, issues, and shortcomings in BIM-to-BEM interoperability process (BBIP) by proposing a detailed classification for these issues and studying the available solutions. The paper also explains how a corrective middleware, which is developed by the authors using Python, can be utilized to modify a gbXML file prior to adoption in energy simulation to resolve the issues related to building envelope in BBIP. To do so, initially a review is presented on research studies focused on different types of BIM schemas such as IFC and gbXML and energy simulation tools capable of reading these files such as Green Building Studio (GBS), DesignBuilder, Integrated Environmental Solutions-Virtual Environment (IES), and OpenStudio. In addition, some of the challenges in the application of BIM for energy simulation such as interoperability issues, lack of standards, and lack of easy solutions for extending existing BIM schemas and available corresponding solutions are also reviewed. With the focus on building envelope in mind, three case studies are discussed to observe the challenges and issues with respect to BBIP using Revit, GBS, and OpenStudio. Moreover, these case studies provide an opportunity to investigate the application of corrective middleware tools similar to what is developed in the study presented. Highlights • A brief review of Building Energy Modeling (BEM) tools is provided • Building Information Modeling (BIM) file types are reviewed and compared • Existing challenges, issues, and shortcomings in BIM to BEM interoperability process (BBIP) are identified • Existing solutions for issues in BBIP are reviewed and a corrective tool is developed and proposed to solve issues related to gbXML files involved in BBIP • A comprehensive categorization is proposed for issues in BBIP. [ABSTRACT FROM AUTHOR]

Abstract Wide bandgap (WBG) semiconductor devices represent an attractive developing technology for power applications that is recently gaining commercial ground. GaN has advantages as one of the top contenders with high bandgap, high mobility, high saturation velocity, and high breakdown voltage. GaN enhancement-mode devices are favored over depletion-mode devices for power electronics applications and are only recently becoming commercially available. The enhancement-mode device investigated in this work is a GaN-gate injection transistor (GIT) in which the normally-off operation is achieved with an additional p -doped gate. This paper presents current-voltage (I-V) characteristics of GaN-GIT device using a physics based compact model as well as TCAD (Technology Computer-Aided Design) numerical simulation to predict and model the device behavior of the GIT. This paper presents a comparison of the TCAD simulation results with a compact model intended for low frequency applications in power electronics in the KHz to MHz range. [ABSTRACT FROM AUTHOR]

Abstract In this paper an automated CAD tool that can be used in integrated circuit technology characterization is proposed. The proposed methodology fills the gap found in old, as well as, new IC design methodologies. The tool allows the user to perform a rapid and full characterization for different device models available in a process design kit (PDK). A set of pre-defined suite of test-benches are created to cover different aspects of circuit design. A seamless integration of the tool in typical design environments is achieved using SKILL code and OCEAN script. Moreover, the tool can compare different PDK releases or different technologies in terms of DC/AC performance, high frequency operation, leakage, and layout area efficiency. The paper presents the tool structure, interface, and capabilities. Finally, a characterization example is applied to CMOS 130 nm technology; results are shown for different devices characterization: MOSFET, BJT, Diode, Resistor, and Capacitor. [ABSTRACT FROM AUTHOR]

Abstract Parametric CAD modelling systems requires the successful CAD model creation and modification in the product design phase. It demands persistent identification of topological entities, retrieving faces, edges, and vertexes are done with those entities specific unique names called persistent IDs. Those names should contain their unique properties which would be unambiguous among topological entities. In this paper, we are going to present reviews of existing persistent identification mechanisms and discuss their merits and demerits based on topology based approach, geometry based approach, or a combination of both ones. This review paper tries to define persistent identification mechanism not simply by topology and geometry but by their unique properties like feature orientation based persistent identification, faceIDGraph based persistent identification etc. Previous papers classified the persistent identification mechanism by only the topological or geometrical properties of entities which are too simple to understand the inside merits and demerits of that method. This paper also identifies the advantages and limitations of the current persistent identification approaches while suggesting a new approach should be developed consisting of both topology and geometry based approach. This paper also suggests the future direction of persistent identification of parametric CAD models and their entities. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is to propose a new graphical method for a planetary gear train (PGT) analysis. This is a fully graphical method that determines the rotational speeds of all transmission components, as well as the torque, power flow, power losses, and efficiency of any PGT. With this method, a sketcher workbench available in any modern computer-aided design (CAD) system can be used. This provides an interactive way to work. Both the construction of the geometric model and the interpretation of the results are intuitive, which facilitates error identification. Observing the impact of the selected input data or model parameters on the model behavior is extremely easy and can even be animated. It is believed that the presented method can streamline the PGT design process. [ABSTRACT FROM AUTHOR]

Highligths • Strategy envisaging a virtual/mock surgery on a CAD/AM model of the patient cranium. • Additive Manufacturing based intervention simulation. • Additive Manufacturing based design of implants. • Complex craniofacial defects corrected using a single-step intervention. Abstract Background and objective The purpose of the present paper is to pave the road to the systematic optimization of complex craniofacial surgical intervention and to validate a design methodology for the virtual surgery and the fabrication of cranium vault custom plates. Recent advances in the field of medical imaging, image processing and additive manufacturing (AM) have led to new insights in several medical applications. The engineered combination of medical actions and 3D processing steps, foster the optimization of the intervention in terms of operative time and number of sessions needed. Complex craniofacial surgical intervention, such as for instance severe hypertelorism accompanied by skull holes, traditionally requires a first surgery to correctly "resize" the patient cranium and a second surgical session to implant a customized 3D printed prosthesis. Between the two surgical interventions, medical imaging needs to be carried out to aid the design the skull plate. Instead, this paper proposes a CAD/AM-based one-in-all design methodology allowing the surgeons to perform, in a single surgical intervention, both skull correction and implantation. Methods A strategy envisaging a virtual/mock surgery on a CAD/AM model of the patient cranium so as to plan the surgery and to design the final shape of the cranium plaque is proposed. The procedure relies on patient imaging, 3D geometry reconstruction of the defective skull, virtual planning and mock surgery to determine the hypothetical anatomic 3D model and, finally, to skull plate design and 3D printing. Results The methodology has been tested on a complex case study. Results demonstrate the feasibility of the proposed approach and a consistent reduction of time and overall cost of the surgery, not to mention the huge benefits on the patient that is subjected to a single surgical operation. Conclusions Despite a number of AM-based methodologies have been proposed for designing cranial implants or to correct orbital hypertelorism, to the best of the authors' knowledge, the present work is the first to simultaneously treat osteotomy and titanium cranium plaque. [ABSTRACT FROM AUTHOR]

Highlights • This paper proposes a new CAD model for pancreas cancer on PET/CT images, including (1) pancreas segmentation, (2) feature extraction and selection, (3) classifier design, respectively. • Pancreas segmentation is performed using SLIC on CT pseudo-color images generated by the gray interval mapping (GIP) method. • Dual threshold principal component analysis (DT-PCA) is developed to select the most beneficial feature combination, which not only considers principal features but also integrates some non-principal features into a new polar angle representation. • Hybrid feedback support vector machine-random forest (HFB-SVM-RF) model is designed to identify normal pancreas or pancreas cancer and the key is to use 8 kinds of SVMs to establish the decision trees of RF. • Contrast experiments in 10-fold cross validation demonstrate the efficiency and accuracy of the proposed CAD model as well as its performance advantages as compared with related methods. Abstract Background and objective: Pancreas cancer is a digestive tract tumor with high malignancy, which is difficult for diagnosis and treatment at early time. To this end, this paper proposes a computer aided diagnosis (CAD) model for pancreas cancer on Positron Emission Tomography/Computed Tomography (PET/CT) images. Methods: There are three essential steps in the proposed CAD model, including (1) pancreas segmentation, (2) feature extraction and selection, (3) classifier design, respectively. First, pancreas segmentation is performed using simple linear iterative clustering (SLIC) on CT pseudo-color images generated by the gray interval mapping (GIP) method. Second, dual threshold principal component analysis (DT-PCA) is developed to select the most beneficial feature combination, which not only considers principal features but also integrates some non-principal features into a new polar angle representation. Finally, a hybrid feedback-support vector machine-random forest (HFB-SVM-RF) model is designed to identify normal pancreas or pancreas cancer and the key is to use 8 types of SVMs to establish the decision trees of RF. Results: The proposed CAD model is tested on 80 cases of PET/CT data (from General Hospital of Shenyang Military Area Command) and achieves the average pancreas cancer identification accuracy of 96.47%, sensibility of 95.23% and specificity of 97.51%, respectively. In addition, the proposed pancreas segmentation method is also evaluated using a public dataset with 82 3D CT scans from the National Institutes of Health (NIH) Clinical Center and its performance is found to surpass other methods, with a mean Dice coefficient of 78.9% and Jaccard index of 65.4%. Conclusions: Collectively, contrast experiments in 10-fold cross validation demonstrate the efficiency and accuracy of the proposed CAD model as well as its performance advantages as compared with related methods. [ABSTRACT FROM AUTHOR]

Abstract Product manufacturers have spent the last years improving productivity and process efficiency in order to face increasingly competitive markets. Today, the visibility of technological innovations has become essential to achieve the targeted market. It is now very difficult for a product manufacturer to reach customers without owning a website that is visible on search engine results pages. The goal of this paper is to build information channels between a company and its customers through improving both a company's content of information on the Web and its website rank on the Internet through search engine results pages. Company information and knowledge are distributed through multiple stakeholders. The problem of building information channels between a company and customers is solved through a collaborative and distributed approach, on the one hand, and is supported by decision-making tools, on the other hand. The paper proposes an engineering model for building information channels and improving the visibility of the company on the Web. Agents are used for the implementation of the approach. The proposed model and its implementation handle the requirements, constraints, functions and solutions for improving Web visibility. The prototype tool, called CAWIS (Computer Aided Web Information Sharing), examines Web visibility in real time and evaluates the performance of the proposed content of information. CAWIS allows an exploratory and open way for building information channels and improving the visibility of product manufacturers on the Web. [ABSTRACT FROM AUTHOR]

Abstract Mass-customization has forced manufacturing companies to put significant efforts to digitize and automate their engineering and production processes. When new products are to be developed and introduced the production is not alone to be automated. The application of knowledge regarding how the product should be designed and produced based on customer requirements also must be automated. One big academic challenge is helping industry to make sure that the background knowledge of the automated engineering processes still can be understood by its stakeholders throughout the product life cycle. The research presented in this paper aims to build an infrastructure to support a connectivistic view on knowledge in knowledge based engineering. Fundamental concepts in connectivism include network formation and contextualization, which are here addressed by using graph theory together with information filtering techniques and quality assurance of CAD-models. The paper shows how engineering knowledge contained in spreadsheets, knowledge-bases and CAD-models can be penetrated and represented as filtered graphs to support a connectivistic working approach. Three software demonstrators developed to extract filtered graphs are presented and discussed in the paper. [ABSTRACT FROM AUTHOR]

This paper looks at the challenge of performing Computational Fluid Dynamic simulations against models of real world environments and objects. The difficulty for these simulations is the effort required to render complex objects and environments, as well as the computational power required to solve them. To assist with the first problem, this paper presents a process for importing Building Information Models or 3D CAD models into ANSYS workbench, a popular CFD environment in industry. In order to address computational concerns, this paper also introduces and discusses a system, LODOS, designed to aid in importation and set-up of high complexity models by selectively reducing geometric complexity. This paper presents preliminary results from the use of this system to import two Building Information Models into ANSYS Workbench, showing the current strengths of the system, as well as discussing its current limitations. [ABSTRACT FROM AUTHOR]

A semi-autonomous robotic system dedicated to road and train bridge inspection is presented in this paper. So far, bridge inspections have been performed manually by workers who either climb and rappel or use so-called mobile negative cherry pickers or specific mobile assemblies. This is a dangerous and tedious task which must be carried out during night time or when the traffic on the bridge is stopped, for safety reasons. The installation of mobile assemblies is costly, time consuming and they become not compliant with recent structures. Moreover, manual inspections require counting, measuring, locating and taking pictures of small cracks. The quality of these manual operations depends not only on the experience but also on the level of fatigue of the workers. The robotic inspection system proposed in this paper consists of three main components: a customized truck, a mobile robotic mechanism which takes pictures of the entire area of interest, and a software which automatically associates these pictures with the CAD model of the bridge. Afterwards at office, users browse the pictures of the surfaces of the bridge with the help of the CAD software and a dedicated plugin to detect, measure and comment the bridge defects to process later. The result is summed up into a report generated by the software. The requirements and the mechanical design of this system are described and an overview of the inspections realized so far with it is provided. [ABSTRACT FROM AUTHOR]