A Contribution to Conveying Quality Criteria in Mechanical CAD Models and Assemblies through Rubrics and Comprehensive Design Intent Quantification

Esta investigación examinó el uso de rúbricas de ensamblaje, describiendo su evolución a partir de rúbricas de piezas, y estudió cómo afectan a la autoevaluación de los estudiantes. También se valoró la evaluación de los estudiantes por los instructores, encontrando que, mientras que las rúbricas de ensamblaje fueron parcialmente comprendidas y utilizadas de manera eficiente por los estudiantes, éstas fueron usadas con más éxito por los instructores. En esta investigación se han abordado estrategias diseñadas para mejorar la comunicación de la intención de diseño en modelos CAD, acrecentando así su calidad, con directrices dirigidas a evaluar su eficiencia. Es evidente que se necesitan métricas dirigidas hacia la instrucción de la intención de diseño, ya que la intención de diseño transferida a través de modelos CAD puede realizarse en tres etapas con criterios contradictorios que deben ser equilibrados para llegar a la mejor estrategia de modelado. La investigación ha incluido el desarrollo de un método de validación que demuestra que las rúbricas son dispositivos útiles para garantizar una comunicación consistente de la intención de diseño, y son fundamentales no sólo para evaluar, sino también para comunicar las expectativas del instructor. En esta investigación se examinó cómo definir claramente las cualidades de la intención de diseño para permitir una más fácil evaluación de un ensamblaje CAD. Para todas las dimensiones de la rúbrica, se encontró más concordancia y correlación entre instructores que entre instructores y estudiantes. Existe una correlación moderada/fuerte entre los instructores para las dimensiones de la validez, completitud, concisión y claridad, mientras que existe una ligera correlación para las dimensiones de consistencia e intención del diseño. En segundo lugar, las rúbricas también pueden ser descritas como estáticas o dinámicas. Las rúbricas estáticas, existen sólo en papel, no proporcionan retroalimentación inmediata al educando. Las rúbricas dinámicas realizan cálculos que proporcionan observaciones de evaluación inmediatas al usuario. Además, pueden adaptarse a situaciones específicas dependiendo de la capacidad del usuario. Las rúbricas electrónicas son ideales para rúbricas dinámicas, y permiten el uso y desarrollo de rúbricas adaptativas y adaptables, como se describe a continuación. En tercer lugar, las rúbricas deben ser adaptables lo que debería hacerlas fácilmente comprensibles y fáciles de usar, y adaptativas. Las rúbricas de evaluación se usan cuando un experto determina el progreso pedagógico de un educando, mientras que las rúbricas formativas son empleadas por los propios estudiantes, para trazar su progreso e identificar las deficiencias escolares para las que necesitan apoyo. Las rúbricas se deben refinar y mejorar de forma continuada, en un proceso iterativo y colaborativo, hasta que se alcance un acuerdo satisfactorio, tanto entre evaluadores como entre evaluadores y alumnos. Por ello, se desarrollaron mapas de aserciones que ilustran el modo en que la estrategia de expansión-contracción adapta las rúbricas al progreso del aprendiz de CAD, a la vez que ayudan a comprender las diferentes dimensiones de la rúbrica. Basándose en los experimentos con las rúbricas de ensamblajes, es evidente que las pequeñas diferencias entre los instructores sugieren que la rúbrica de ensamblajes propuesta es lo suficientemente sofisticada como para proporcionar una evaluación acumulativa imparcial del desempeño del alumno. En consecuencia, se puede afirmar con confianza que los evaluadores pueden usarse indistintamente sin sacrificar la precisión. Sin embargo, la rúbrica de ensamblaje posee una eficacia finita para producir una autoevaluación formativa de las habilidades de ensamblaje CAD para nuevos alumnos.This research examined the use of assembly rubrics, described how they evolved from parts rubrics, and studied how they affect student self-evaluation. Instructor assessment of students was also evaluated, finding that while the assembly rubrics were partially understood and effectively used by the students, they were more successfully utilized by the instructors. Strategies designed to improve design intent communication in CAD models, in order to enhance their quality, with guidelines targeted to evaluate efficiency, have been addressed with this research. It is apparent that metrics directed toward the instruction of design intent are needed, since design intent transferred through CAD models can be performed at three stages with competing tradeoffs that must be balanced to arrive at the best modeling strategy. Research included the development of a validation approach that reflects that rubrics are valuable devices to expedite consistent design intent communication, and are vital not only for evaluation, but also for the communication of instructor expectations. This research examined how to clearly define qualities of design intent to enable easier CAD assembly assessment. It has been found that there is more inter-rater agreement and correlation between instructors than between instructors and students, for all rubric dimensions. There is strong to moderate correlation between instructors for the dimensions of validity, completeness, conciseness, and clarity, while slight correlation exists for the dimensions of consistency and design intent. Secondly, rubrics can also be described as being either static or dynamic. Static rubrics, existing in paper form only, do not provide immediate feedback to the learner. Dynamic rubrics perform calculations that provide immediate evaluative observations to the user. Besides, they can be independently adapted to specific situations depending on the capability of the user. Electronic rubrics are ideally suited for dynamic rubrics, and permit the use and development of both adaptable and adaptive rubrics, as described next. Thirdly, rubrics need to be adaptable which should make them easily understood and user-friendly, and adaptive (rubric can change itself, depending on the usage pattern). Evaluative rubrics are used when an expert determines the pedagogical progress of a learner, while formative rubrics are employed by the learners themselves, in order to chart their progress and identify scholastic deficiencies that are in need of remediation. Rubrics must be continually refined and improved, in an iterative, collaborative process, until satisfactory agreement is attained, both between raters, but also between raters and learners. Thus, assertions maps were developed, illustrating how the expand-contract strategy adapts the rubrics to CAD trainee progress, while assisting the understanding of the different rubric dimensions. Based on the assembly rubric experiments, it is apparent that the small differences between instructors suggests that the proposed assemblies rubric is sufficiently sophisticated to furnish an unbiased accumulative assessment of student performance. Accordingly, it can be confidently stated that raters can be used interchangeably without sacrificing accuracy. However, the assembly rubric possesses finite efficacy to produce formative self-evaluation of CAD assembly skills for new learners.Aquesta investigació examinà l'ús de rúbriques de acoblament, descrivint la seua evolució a partir de rúbriques de peces, i estudià cóm afecten a la autoavaluació dels estudiants. També es va valorar la avaluació dels estudiants per els instructors, trobant que, mentre que les rúbriques de acoblament van ser parcialment compreses i fetes servir de manera eficient per els estudiants, van ser usades amb mes èxit per els instructors. En aquesta investigació s'han abordat estrategues dissenyades per a millorar la comunicació de la intenció de disseny en models CAD, creixentat així la seua qualitat, amb directrius dirigides a avaluar la seua eficiència. Es evident que es necessiten mètriques dirigides cap a la instrucció de la intenció de disseny, ja que la intenció de disseny transferida a través de models CAD pot realitzar-se en tres etapes amb criteris contradictoris que deuen ser equilibrats per a arribar a la millor estratègia de modelatge. La investigació ha inclòs el desenvolupament de un mètode de validació que demostra que las rúbriques son dispositius útils per a garantir una comunicació consistent de la intenció de disseny, i son fonamentals no només per a avaluar, però també per a comunicar les expectatives de l'instructor. En aquesta investigació s'examinà com definir clarament les qualitats de la intenció de disseny per a permetre una mes fàcil avaluació de un acoblament CAD. Per a totes les dimensions de la rúbrica, es va trobar mes concordança i correlació entre instructors que no pas entre instructors i estudiants. Existeix una correlació moderada/fort entre els instructors per a les dimensions de la validesa, completesa, concisió i claredat, mentre que existeix una lleugera correlació per a les dimensions de consistència i intenció del disseny. En segon lloc, les rúbriques també poden ser descrites com estàtiques o dinàmiques. Les rúbriques estàtiques, existeixen sòls en paper, no proporcionen retroalimentació immediata a l'educand. Les rúbriques dinàmiques realitzen càlculs que proporcionen observacions de avaluació immediates al usuari. A mes, poden adaptar-se a situacions específiques dependent de la capacitat de l'usuari. Les rúbriques electròniques son ideals per a rúbriques dinàmiques, i permeten l'ús i desenvolupament de rúbriques adaptatives i adaptables, como es descriu a continuació. En tercer lloc, les rúbriques deuen ser adaptables, el que deuria ferles fàcilment comprensibles i fàcils d'usar, i adaptatives. Les rúbriques d'avaluació se usen quant un expert determina el progrés pedagògic de un educand, mentre que les rúbriques formatives son fetes servir per els propis estudiants, per a traçar el seu progrés i identificar les deficiències escolars para a les que necessiten suport. Les rúbriques es deuen refinar i millorar de forma continuada, en un procés iteratiu i col·laboratori, fins que se arriba a un acord satisfactori, tant entre avaluadors como entre avaluadors i alumnes. Por això, es desenvoluparen mapes de assercions que il·lustren el mode en que la estratègia de expansió-contracció adapta les rúbriques al progres del aprenent de CAD, a la vegada que ajuden a comprendre les diferents dimensions de la rúbrica. Basant-se en els experiments amb les rúbriques de acoblaments, es evident que les xicotetes diferencies entre els instructors suggereixen que la rúbrica de acoblaments proposta es lo suficientment sofisticada com per a proporcionar una avaluació acumulativa imparcial del acompliment de l'alumne. En conseqüència, es pot afirmar amb confiança que els avaluadors poden usar-se indistintament sense sacrificar la precisió. No obstant, la rúbrica de acoblaments posseeix una eficàcia finita per a produir una autoavaluació formativa de les habilitats de acoblament CAD per a nous alumnes.Otey, JM. (2017). A Contribution to Conveying Quality Criteria in Mechanical CAD Models and Assemblies through Rubrics and Comprehensive Design Intent Quantification [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/94627TESI

Approach for developing coordinated rubrics to convey quality criteria in MCAD training

This paper describes an approach to convey quality-oriented strategies to CAD trainees by embedding quality criteria into rubrics so as to force CAD trainees to understand them early in their instruction. To this end, the paper analyzes how CAD quality criteria can be organized around quality dimensions and embedded into rubrics in order to enforce quality modeling during the CAD training of novice product designers. Hence, the ambit of this study is training with history-based parametric feature-based MCAD systems, although the general conclusions are believed to be adaptable to other CAD training scenarios. Furthermore, it introduces an approach based on progressive refinement, which results in an assertions map that indicates quality dimensions vs. sequence of tasks for CAD models. The map illustrates how the expand contract strategy adapts the rubrics to CAD trainee progress and assists them in comprehending the different dimensions of the rubrics. The paper also highlights lessons learned on the suitability of using separate rubrics for different tasks, the need of accurately timing the expand contract process, and on the convenience of supporting rubrics with suitable teaching, which must convey good practices and evaluation tools through rubrics. The experiments describe the different lessons learned and illustrate the suggested process for replicating our approach for further developing rubrics adapted to other scenarios.Company, P.; Contero, M.; Otey, J.; Plumed, R. (2015). Approach for developing coordinated rubrics to convey quality criteria in MCAD training. Computer-Aided Design. 63:101-117. doi:10.1016/j.cad.2014.10.001S1011176

Structure-Guided Recombination Creates an Artificial Family of Cytochromes P450

Creating artificial protein families affords new opportunities to explore the determinants of structure and biological function free from many of the constraints of natural selection. We have created an artificial family comprising ~3,000 P450 heme proteins that correctly fold and incorporate a heme cofactor by recombining three cytochromes P450 at seven crossover locations chosen to minimize structural disruption. Members of this protein family differ from any known sequence at an average of 72 and by as many as 109 amino acids. Most (>73%) of the properly folded chimeric P450 heme proteins are catalytically active peroxygenases; some are more thermostable than the parent proteins. A multiple sequence alignment of 955 chimeras, including both folded and not, is a valuable resource for sequence-structure-function studies. Logistic regression analysis of the multiple sequence alignment identifies key structural contributions to cytochrome P450 heme incorporation and peroxygenase activity and suggests possible structural differences between parents CYP102A1 and CYP102A2

Explicit Communication of Geometric Design Intent in CAD: Evaluating Annotated Models in the Context of Reusability

CAD model reusability is largely determined by a proper communication of design intent, which is usually expressed implicitly within the model. Recent studies have suggested the use of 3D annotations as a method to embed design information in the model’s geometry and make part of the design knowledge explicitly available. In this paper, we evaluate the effectiveness of this method and analyze its impact in model alteration tasks. Our goal is to determine whether annotated models provide significant benefits when performing activities that require a direct manipulation of the geometry. We present the results of a study that measured user performance in two scenarios. First, we tested whether annotations are helpful when inadequate modeling assumptions can be made by designers. Second, we evaluated annotations as tools to communicate design decisions to select the most appropriate solution to a challenge when multiple options are available. In both cases, results show statistically significant benefits of annotated models, suggesting the use of this technique as a valuable approach to improve design intent communication

Assessment of parametric assembly models based on CAD quality dimensions

[EN] An approach to convey CAD quality-oriented strategies to beginning users to create bottom-up assemblies is described. The work builds on previous efforts in the area of single part history-based, feature-based parametric modeling evaluation by defining, testing, and validating a set of quality dimensions that can be applied to MCAD assembly assessment. The process of redefining and adapting dimension descriptors and achievement levels of parts rubrics to make them applicable to assemblies is addressed, then the results of two experimental studies designed to analyze the inter-rater reliability of this approach to assembly evaluation are reported. Results suggest the mechanism is reliable to provide an objective assessment of assembly models. Limitations for the formative selfevaluation of CAD assembly skills are also identified.This work was partially supported by the Spanish grant DPI2017-84526-R (MINECO/AEI/FEDER, UE), project CAL-MBE, Implementation and validation of a theoretical CAD quality model in a Model-Based Enterprise (MBE) context. , and the ANNOTA2 project funded by Universitat Politècnica de València.Otey, J.; Company, P.; Contero, M.; Camba, JD. (2019). Assessment of parametric assembly models based on CAD quality dimensions. Computer-Aided Design and Applications. 16(4):628-653. https://doi.org/10.14733/cadaps.2019.628-653S62865316

Training Engineers in the Use of Constraints to Create Quality 2D Pro les for 3D Models

Historically, different strategies utilized in engineering and technical graphics reflect growing concern about improvement in CAD instruction and the introduction of product quality data in curricular activities. Our vision was that early introduction of quality criteria through "good practices" is feasible and increases the quality, robustness, and reliability of CAD models. This paper describes a strategy applied to improve the knowledge of novice CAD users on the use of geometric constraints in 2D parametric profiles. This approach consists of supplementing student training with activities in order to provide rapid and effective feedback. A Chi-Squared Test was performed to assess the effectiveness of this strategy, indicating that trainees need continuous and additional autonomous learning to create quality 2D parametric pro les. Future work will include developments to promote student awareness of the need for quality in 3D models using an online checker that acts as a filter of semantic quality errors while providing feedback

Revisiting the design intent concept in the context of mechanical CAD education

[EN] Design intent is generally understood simply as a CAD model¿s anticipated behavior when altered. However, this representation provides a simplified view of the model¿s construction and purpose, which may hinder its general understanding and future reusability. Our vision is that design intent communication may be improved by recognizing the multifaceted nature of design intent, and by instructing users to convey each facet of design intent through the better-fitted CAD resource. This paper reviews the current understanding of design intent and its relationship to design rationale and builds on the idea that communication of design intent conveyed via CAD models can be satisfied at three levels provided that specialized instruction is used to instruct users in selection of the most suitable level for each intent.Otey, J.; Company, P.; Contero, M.; Camba, J. (2018). Revisiting the design intent concept in the context of mechanical CAD education. Computer-Aided Design and Applications. 15(1):47-60. https://doi.org/10.1080/16864360.2017.1353733S476015

The Somatic Genomic Landscape of Glioblastoma

We describe the landscape of somatic genomic alterations based on multi-dimensional and comprehensive characterization of more than 500 glioblastoma tumors (GBMs). We identify several novel mutated genes as well as complex rearrangements of signature receptors including EGFR and PDGFRA. TERT promoter mutations are shown to correlate with elevated mRNA expression, supporting a role in telomerase reactivation. Correlative analyses confirm that the survival advantage of the proneural subtype is conferred by the G-CIMP phenotype, and MGMT DNA methylation may be a predictive biomarker for treatment response only in classical subtype GBM. Integrative analysis of genomic and proteomic profiles challenges the notion of therapeutic inhibition of a pathway as an alternative to inhibition of the target itself. These data will facilitate the discovery of therapeutic and diagnostic target candidates, the validation of research and clinical observations and the generation of unanticipated hypotheses that can advance our molecular understanding of this lethal cancer

Leveraging Mechanical 3D CAD Systems Through Improved Model Quality Based on Best Practices and Rubrics

CAD data quality may be leveraged by quality-oriented CAD instructional strategies, but current mechanical CAD practice fails in enforcing quality. The concept of CAD model quality is reviewed to discover how to convey different dimensions of quality through rubrics. The paper describes lessons learned from pilot studies designed to gain knowledge on introducing best practices throughout the training period of novice product designers. Best practices are conveyed by rubrics, so leading to increased quality in CAD models. Rubrics must adapt to the specific concept practiced at each stage of the training period. In this way, they become helpful in disclosing which currently available strategies and tools to enforce quality may be early comprehended and how they are better introduced. Lessons learned from pilot studies are proposed to be reformulated as strong hypothesis that should be validated or rejected in the future, by way of experiments with suitable statistical power