Graph traversal | EPFL Graph Search

In computer science, graph traversal (also known as graph search) refers to the process of visiting (checking and/or updating) each vertex in a graph. Such traversals are classified by the order in which the vertices are visited. Tree traversal is a special case of graph traversal. Redundancy Unlike tree traversal, graph traversal may require that some vertices be visited more than once, since it is not necessarily known before transitioning to a vertex that it has already been explored. As graphs become more dense, this redundancy becomes more prevalent, causing computation time to increase; as graphs become more sparse, the opposite holds true. Thus, it is usually necessary to remember which vertices have already been explored by the algorithm, so that vertices are revisited as infrequently as possible (or in the worst case, to prevent the traversal from continuing indefinitely). This may be accomplished by associating each vertex of the graph with a "color" or "visitati

How Florist Apprentices Explore Bouquet Designs: Supporting Design Space Exploration for Vocational Students

Pierre Dillenbourg, Kevin Gonyop Kim, Catharine Regina Monika Maria Oertel Genannt Bierbach

Context: Exploring the design space is an important process in a design task. In this study, we considered design space exploration for the learners in vocational education and training (VET). The goal of the study was to investigate how they explore the design space while focusing on the effect of a graph-like interface on the learner’s understanding of the design space. With florists as the target profession, we investigated how the apprentices explore design variations, what they would gain from such activity, and how we can support this process. Approach: We developed a web application called BloomGraph that allows learners to explore design variations. It provides a graph-based interface that enables the systematic variation of design. Using the BloomGraph application, we conducted an experimental study with 44 florist apprentices in Switzerland to investigate the effect of the graph-based interface which provides a structured way of exploring the design space. The experimental group was given the graph-based interface to explore design variations while the control group had a linear-based interface. We compared them in terms of the number of bouquets explored, time of exploration, diversity of bouquets explored, and the learning gain in terms of the understanding of the design space measured using pre and post-tests. We also analyzed the strategies adopted by the participants for the graph navigation and the visual exploration behavior using the eye gaze data. Findings: Our analysis shows that the graph-based interface fosters a better understanding of the size of the design space and more efficient navigation towards a goal design in terms of the number of intermediate designs but with longer exploration of each intermediate design compared to the linear-based interface. Regarding the behavioral patterns in graph exploration, the participants who showed more strategic behavior in the design choices acquired a better understanding of the design space. Additionally, we trained a model that predicts the next choice of a learner using eye tracking data. It provides a reasonable accuracy that opens new possibilities for future studies. Conclusion: The findings of this study support the feasibility of design space exploration as a digital activity for VET learners and show how the learners can benefit from it. The contribution of the paper includes the validation of the idea with florist apprentices and the demonstration of how the process can be supported using a structured interface and the learner behavior analysis. This paper shows how a design exploration activity can provide an added value in the learning of an apprentice in a design-related VET system.

2021

BloomGraph: Graph-Based Exploration of Bouquet Designs for Florist Apprentices

Pierre Dillenbourg, Kevin Gonyop Kim, Catharine Regina Monika Maria Oertel Genannt Bierbach

Exploring design space is an important process in finding solutions to a design task. In this paper, we present BloomGraph, an online application developed for florist apprentices to explore the space of bouquet designs. BloomGraph provides a graph-based interface that allows users to explore design variations as they follow the nodes in a graph. This paper presents the preliminary result from an experimental study with florist apprentices in vocational education in Switzerland. Based on the early findings, we discuss the potential of the application as a learning tool and address the next steps to be followed.

SPRINGER INTERNATIONAL PUBLISHING AG2019

BloomGraph: Graph-Based Exploration of Bouquet Designs for Florist Apprentices

Pierre Dillenbourg, Kevin Gonyop Kim, Catharine Regina Monika Maria Oertel Genannt Bierbach

Springer, Cham2019

How Florist Apprentices Explore Bouquet Designs: Supporting Design Space Exploration for Vocational Students

Pierre Dillenbourg, Kevin Gonyop Kim, Catharine Regina Monika Maria Oertel Genannt Bierbach

2021