Hysteresis in Interoperability: Workflows Involving Multiple Representations of 3D Models

Author(s):  
Prakhar Jaiswal ◽  
Rahul Rai ◽  
Saigopal Nelaturi

Various 3D solid model representation schemes are developed to capture and process geometrical information of physical 3D objects as accurately and precisely as possible with the consideration of storage and computational complexity. These representation schemes are error prone, and their limitations prohibit them to capture all the pertinent information perfectly for a complex 3D object. Many applications in design involve repetitive conversions between several representation schemes to efficiently evaluate and operate on solid models. Mapping one representation to other degrades the quality, correctness, and completeness of the information content. In this paper, we quantify the degradation of the proxy representation models by taking inspiration from the hysteresis concept applied in different fields, such as magnetism, mechanics, control systems, cell biology, and economics. We propose a method to compute the error remanence using quantitative measures of information content and quality of proxy models. We also discuss the areas of future research such as sequencing of operations in computational work-flows that would benefit by utilizing the error remanence metric.

2019 ◽  
Vol 103 (9-10) ◽  
pp. 493-504
Author(s):  
Matthew Jian-Qiao Peng ◽  
Xiangyang Ju ◽  
Hai-Yan Chen ◽  
Bai Bo ◽  
XinXu Li

Purpose: A series models of surgical internal fixation for femoral neck fracture of Pauwels II will be constructed by an innovative approach of finite element so as to determine the most stable fixation by comparison of their biomechanical performance. Method: Seventeen specimens of proximal femurs scanned by computed tomography in Digital Imaging and Communications in Medicine (DICOM) format were input onto Mimics rebuilding 3D models; their stereolithography (STL) format dataset were imported into Geomagic Studio (3D Systems, Rock Hill, South Carolina) for simulative osteotomy and non-uniform rational basis spline kartograph; the generated IGS dataset were interacted by UG to fit simulative 3D-solid models; 3 sorts of internal fixators were expressed in 3D model by ProE (PTC, Boston, Connecticut) program virtually. Processed by HyperMesh (Altair, Troy, Michigan), all compartments (fracture model + internal immobilization) were assembled onto 3 systems actually as: Dynamic hip screw (DHS) / Lag screw (LS) / DHS+LS. Eventually, a numerical model of finite elemental analysis was exported to ANSYS for solution. Result: Three models of internal fixations for femoral neck fracture of Pauwels II were established and validated effectively, the stress and displacement of each internal pin were analyzed, the advantages of each surgical therapy for femoral neck fracture of Pauwels II were compared and demonstrated synthetically as: “The contact stress of 3-LS-system was checked to be the least; the interfragmentary displacement of DHS+1-LS assemblages was assessed to be the least.” Conclusion: 3-LS-system is recommended to be a clinical optimization for Pauwels II femoral neck facture, by this therapeutic fixation mechanically, breakage of fixators, or secondary fracture rarely occurs.


Author(s):  
Vivek A. Sujan

In field environments it is not usually possible to provide robots in advance with valid geometric models of its environment and task element locations. The robot or robot teams need to create and use these models to locate critical task elements by performing appropriate sensor based actions. Here, an information-based iterative algorithm to intelligently plan the robot’s visual exploration strategy is proposed to enable it to efficiently build 3D models of its environment and task elements. The method assumes mobile robot or vehicle with cameras carried by articulated mounts. The algorithm uses the measured scene information to find the next camera position based on expected new information content of that pose. This is achieved by utilizing a metric derived from Shannon’s information theory to determine optimal sensing poses for the agent(s) mapping a highly unstructured environment. Once an appropriate environment model has been built, the quality of the information content in the model is used to determine the constraint-based optimum view for task execution. Experimental demonstrations on a cooperative robot platform performing an assembly task in the field show the effectiveness of this algorithm for single and multiple cooperating robotic systems.


2015 ◽  
Vol 760 ◽  
pp. 87-92
Author(s):  
Panagiotis Kyratsis ◽  
Athanasios Manavis

Drilling is considered to be one of the mostly used processes for holemaking. Researchers have followed three different approaches for its simulation i.e. analytic, experimental and numerical. Nowadays the direct access of scientists to the Application Programming Interface (API) of several CAD systems led to an increased number of finite element simulations based on CAD 3D models of drilling tools. The present paper uses a CAD system and via its API a kinematic model is created. Different tool parameters and cutting conditions are introduced; a series of 3D solid models for the tool, the workpieces and the undeformed chips are created and the resulted thrust forces are predicted in both the main edges and the chisel edge. The proposed methodology is experimentally verified using Al7075 for the workpiece and HSS for the tool material. In addition, it provides the basis for a series of new applications in other manufacturing processes based on CAD created geometries.


Author(s):  
Karthik Viswanathan ◽  
Sagar Chowdhury ◽  
Zahed Siddique

Computer-Aided Design (CAD) is used extensively during mechanical product design, which involves creating 3D models of components and then assembling them into modules and systems. Methods and tools to compare components and identify a common platform using these 3D CAD models of components would facilitate faster specification of product family architecture. Hence, there is a need to develop means for comparing component geometry, in order to identify the common and distinct features, determine component commonality, and identify a common platform for the set of components. This paper presents an approach to determine geometric commonality between components from their 3D solid models. The approach consists of performing a pair-wise comparison between components. To measure commonality for a pair of components, first all feature-pair’s dimensions and positions are measured, which then combined to give the overall component-pair commonality.


Transport ◽  
2015 ◽  
Vol 30 (2) ◽  
pp. 202-216 ◽  
Author(s):  
Josef Bulíček ◽  
Pavel Drdla

This paper is based on the analysis of websites of Urban Public Transport (UPT) made in different states. The paper proposes a standard of ‘minimal information websites content’ named as ‘Passenger Friendly Web’. Information content is divided into a set of elements. Their weights are determined by expert evaluation with the support of mathematics, especially of Saaty’s Method. Possibilities for future research are also regarded. Results can be applied to all Internet websites of UPT.


2021 ◽  
Author(s):  
Rahul Sharan Renu ◽  
Gregory Mocko

Abstract Many manufacturing enterprises have large collections of solid models and text-based assembly processes to support assembly operations. These data are often distributed across their extended enterprise. As these enterprises expand globally, there is often an increase in product and process variability which can often lead to challenges with training, quality control, and obstacles with change management to name a few. Thus, there is a desire to increase the consistency of assembly work instructions within and across assembly locations. The objective of this research is to retrieve existing 3d models of components and assemblies and their associated assembly work instructions. This is accomplished using 3d solid model similarity and text mining of assembly work instructions. Initially, a design study was conducted in which participants authored assembly work instructions for several different solid model assemblies. Next, a geometric similarity algorithm was used to compute similarity scores between solid models and latent semantic analysis is used to compute the similarity between text-based assembly work instructions. Finally, a correlation study between solid model-assembly instruction tuples is computed. A moderately strong positive correlation was found to exist between solid model similarity scores and their associated assembly instruction similarity scores. This indicates that designs with a similar shape have a similar assembly process and thus can serve as the basis for authoring new assembly processes. This aids in resolving differences in existing processes by linking three-dimensional solid models and their associated assembly work instructions.


Vaccines ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 65 ◽  
Author(s):  
Thomas van Ee ◽  
Heleen Van Acker ◽  
Tom van Oorschot ◽  
Viggo Van Tendeloo ◽  
Evelien Smits ◽  
...  

Dendritic cell (DC) vaccines show promising effects in cancer immunotherapy. However, their efficacy is affected by a number of factors, including (1) the quality of the DC vaccine and (2) tumor immune evasion. The recently characterized BDCA1+CD14+ immunosuppressive cells combine both aspects; their presence in DC vaccines may directly hamper vaccine efficacy, whereas, in patients, BDCA1+CD14+ cells may suppress the induced immune response in an antigen-specific manner systemically and at the tumor site. We hypothesize that BDCA1+CD14+ cells are present in a broad spectrum of cancers and demand further investigation to reveal treatment opportunities and/or improvement for DC vaccines. In this review, we summarize the findings on BDCA1+CD14+ cells in solid cancers. In addition, we evaluate the presence of BDCA1+CD14+ cells in leukemic cancers. Preliminary results suggest that the presence of BDCA1+CD14+ cells correlates with clinical features of acute and chronic myeloid leukemia. Future research focusing on the differentiation from monocytes towards BDCA1+CD14+ cells could reveal more about their cell biology and clinical significance. Targeting these cells in cancer patients may improve the outcome of cancer immunotherapy.


2021 ◽  
Vol 11 (17) ◽  
pp. 7964
Author(s):  
Dan Leordean ◽  
Cristian Vilău ◽  
Mircea Cristian Dudescu

This paper presents three methods of converting complex 3D models of STL type into solid models. For converting the STL models, specific approximation functions from CATIA and Creo Parametric software were used as well as 3D solid modeling methods that used sketches drawn for sections of the specific analyzed model. This conversion is required to get a solid 3D model that can be used for finite element analysis and to be processed using Boolean functions in specific CAD programs. This paper also presents a study of the effectiveness of FEA in respect to the time required for the analysis of each converted model. The analyzed STL files contain data obtained by computer tomography and are the 3D models of the human orthopedic system: the left zygomatic bone and upper part of the right femur. The presented conversion methods can be used by design engineers both in medical applications (where the complexity of forms is well known) for the design of implants and for industrial applications for reverse engineering.


2020 ◽  
Vol 29 (4) ◽  
pp. 2097-2108
Author(s):  
Robyn L. Croft ◽  
Courtney T. Byrd

Purpose The purpose of this study was to identify levels of self-compassion in adults who do and do not stutter and to determine whether self-compassion predicts the impact of stuttering on quality of life in adults who stutter. Method Participants included 140 adults who do and do not stutter matched for age and gender. All participants completed the Self-Compassion Scale. Adults who stutter also completed the Overall Assessment of the Speaker's Experience of Stuttering. Data were analyzed for self-compassion differences between and within adults who do and do not stutter and to predict self-compassion on quality of life in adults who stutter. Results Adults who do and do not stutter exhibited no significant differences in total self-compassion, regardless of participant gender. A simple linear regression of the total self-compassion score and total Overall Assessment of the Speaker's Experience of Stuttering score showed a significant, negative linear relationship of self-compassion predicting the impact of stuttering on quality of life. Conclusions Data suggest that higher levels of self-kindness, mindfulness, and social connectedness (i.e., self-compassion) are related to reduced negative reactions to stuttering, an increased participation in daily communication situations, and an improved overall quality of life. Future research should replicate current findings and identify moderators of the self-compassion–quality of life relationship.


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