Jorge D. Camba

Parametric CAD modeling

CAD model quality in parametric design scenarios largely determines the level of flexibility and adaptability of a 3D model (how easy it is to alter the geometry) as well as its reusability (the ability to use existing geometry in other contexts and applications). In the context of mechanical CAD systems, the nature of the feature-based parametric modeling paradigm, which is based on parent-child interdependencies between features, allows a wide selection of approaches for creating a specific model. Despite the virtually unlimited range of possible strategies for modeling a part, only a small number of them can guarantee an appropriate internal structure which results in a truly reusable CAD model. In this paper, we present an analysis of formal CAD modeling strategies and best practices for history-based parametric design: Delphis horizontal modeling, explicit reference modeling, and resilient modeling. Aspects considered in our study include the rationale to avoid the creation of unnecessary feature interdependencies, the sequence and selection criteria for those features, and the effects of parent/child relations on model alteration. We provide a comparative evaluation of these strategies in the form of a series of experiments using three industrial CAD models with different levels of complexity. We analyze the internal structure of the models and compare their robustness and flexibility when the geometry is modified. The results reveal significant advantages of formal modeling methodologies, particularly resilient techniques, over non-structured approaches as well as the unexpected problems of the horizontal strategy in numerous modeling situations. We analyze three formal CAD modeling strategies for history-based parametric design.User performance was studied using three industrial CAD models with different levels of complexity.Formal modeling methodologies offer significant advantages over non-structured approaches.Modeling methodologies significantly affect reusability.

A survey on 3D CAD model quality assurance and testing tools

Abstract A new taxonomy of issues related to CAD model quality is presented, which distinguishes between explicit and procedural models. For each type of model, morphologic, syntactic, and semantic errors are characterized. The taxonomy was validated successfully when used to classify quality testing tools, which are aimed at detecting and repairing data errors that may affect the simplification, interoperability, and reusability of CAD models. The study shows that low semantic level errors that hamper simplification are reasonably covered in explicit representations, although many CAD quality testers are still unaffordable for Small and Medium Enterprises, both in terms of cost and training time. Interoperability has been reasonably solved by standards like STEP AP 203 and AP214, but model reusability is not feasible in explicit representations. Procedural representations are promising, as interactive modeling editors automatically prevent most morphologic errors derived from unsuitable modeling strategies. Interoperability problems between procedural representations are expected to decrease dramatically with STEP AP242. Higher semantic aspects of quality such as assurance of design intent, however, are hardly supported by current CAD quality testers.

Accessibility and tangible interaction in distributed workspaces based on multi-touch surfaces

Traditional interaction mechanisms in distributed digital spaces often fail to consider the intrinsic properties of action, perception, and communication among workgroups, which may affect access to the common resources used to mutually organize information. By developing suitable spatial geometries and natural interaction mechanisms, distributed spaces can become blended where the physical and virtual boundaries of local and remote spaces merge together to provide the illusion of a single unified space. In this paper, we discuss the importance of blended interaction in distributed spaces and the particular challenges faced when designing accessible technology. We illustrate this discussion through a new tangible interaction mechanism for collaborative spaces based on tabletop system technology implemented with optical frames. Our tangible elements facilitate the exchange of digital information in distributed collaborative settings by providing a physical manifestation of common digital operations. The tangibles are designed as passive elements that do not require the use of any additional hardware or external power while maintaining a high degree of accuracy.

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

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, whi...

Gamifying the Eating Experience: An Interactive Companion for Children’s Nutrition Education and Behavior

We present an interactive companion for children’s nutrition education that capitalizes on digital technology to promote mental and physical stimulation by adding game-like elements to the eating experience. Our device allows children to manage portion sizes easily and promotes the practice of healthy eating habits by interacting with “Cibo,” a healthy kid metaphor that encourages children to learn how different food groups benefit the body. Different parts of the device provide active feedback as the child eats his/her meal. The combination of physical and digital interaction gamifies the eating experience and redefines “playing at the dinner table” into a positive event that nourishes children physically, cognitively, and emotionally.

Understanding emergency workers' behavior and perspectives on design and safety in the workplace

Emergency Medical Services (EMS) is a demanding and hazardous industry. Because of the changing roles in the emergency response system, EMS workers are increasingly expected to provide treatment and care in addition to transport, which increases their task load and susceptibility to harm. This paper serves to outline the EMS field from the workers perspective with the purpose of understanding their views on health, safety, and the work environment, and identify where gaps in worker well-being are exposed. Through direct observation, field studies, and formal interviews with EMS professionals, we discuss where reluctance lies in addressing safety issues and the current efforts to address them. A high prevalence of responses regarding the inadequacy of ambulance restraining systems was reported, as existing interventions do not take into account medic needs.

On the Integration of Tangible Elements with Multi-touch Surfaces for the Collaborative Creation of Concept Maps

Collaborative creative work in small groups can significantly improve learning, particularly when supported by concept maps. Although useful in collaborative environments, most applications for the development of concept maps are designed for personal or small tablet computers, which can limit student communication in a team setting. In addition, the use of these applications usually requires training periods that may reduce the time allotted for regular learning activities. In this context, digital tabletops can effectively promote collaboration and face-to-face communication by providing a large horizontal interactive surface. However, despite its large size, a single tabletop cannot accommodate more than three or four students. Therefore, collaborative learning spaces and work groups with multiple devices become necessary. In such scenarios, the exchange of information between groups is critical. In this paper, we propose the use of tangibles, as a natural mechanism to exchange information by using a distributed collaborative concept map application.

Augmented Reality Experiences in Therapeutic Pedagogy: A Study with Special Needs Students

Information and Communication Technologies (ICTs) have played a major role in shaping our society, affecting nearly all aspects of our daily lives. In educational contexts, the ongoing technological revolution we are experiencing naturally calls for a transformation of traditional teaching and learning processes. The integration and efficient use of emergent technologies have become fundamental challenges in the educational domain. In this paper, we evaluate the use of Augmented Reality (AR) technology in a classroom with middle school special-needs students. Our primary goal is to quantitatively assess whether AR helps special-needs students to improve their results, performance, motivation, and other aspects of the learning process. Information was collected via pre and post questionnaires distributed to participants before and after an intervention. Our results serve as basis for improving future educational AR-related projects and materials.

Design Perception: Combining Semantic Priming With Eye Tracking and Event-Related Potential (ERP) Techniques to Identify Salient Product Visual Attributes

The study of product visual attributes is usually performed through questionnaires which provide information about the conscious subjective opinions of the consumer. This work complements such method by combining Event-Related Potentials (ERP) and Eye-Tracking (ET) techniques and using semantic priming to elicit user perception. Our study focuses on package design and follows the basic structure of classic ERP experiments where participants are presented an ordered sequence of frames (stimuli) in a computer screen for a certain period of time: attention frame, semantic priming frame (descriptive adjective), neutral background, target frame (product image), and a question regarding coherence between priming and target frames. The eye-tracking system works in combination with the ERP experiment. The results of our study reveal the connection between adjectives (semantic priming) and package design attributes (based on the analysis of the N400 ERP component), and the connection between adjectives and the specific visual elements that get more attention (based on the information provided by eye-tracking analysis software).Copyright

Go/No Go Criteria in Formative E-Rubrics.

Learning processes rely on the progressive assimilation and objective assessment of concepts. In this regard, learning rubrics are commonplace. However, the design of these rubrics has focused mainly on scoring (summative rubrics), whereas formative rubrics have received significantly less attention. Electronic formats (e-rubrics) enable dynamic and interactive functionalities that facilitate the adaptable and adaptive delivery of content. In this paper, we examine three characteristics to make formative rubrics more adaptable and adaptive: criteria dichotomization, weighted evaluation criteria, and go/no-go criteria. A new approach to the design of formative rubrics is introduced, where dichotomization and weighted criteria are combined with the use of go/no-go criteria. The approach is discussed as a method to better guide the learner while adjusting to the student’s assimilation pace. Two types of go/no-go criteria (hard and soft) are studied and experimentally validated in a Computer-Aided Design assessment context.