Leveraging Symmetries in Pick and Place

Robotic pick and place tasks are symmetric under translations and rotations of both the object to be picked and the desired place pose. For example, if the pick object is rotated or translated, then the optimal pick action should also rotate or translate. The same is true for the place pose; if the desired place pose changes, then the place action should also transform accordingly. A recently proposed pick and place framework known as Transporter Net captures some of these symmetries, but not all. This paper analytically studies the symmetries present in planar robotic pick and place and proposes a method of incorporating equivariant neural models into Transporter Net in a way that captures all symmetries. The new model, which we call Equivariant Transporter Net, is equivariant to both pick and place symmetries and can immediately generalize pick and place knowledge to different pick and place poses. We evaluate the new model empirically and show that it is much more sample efficient than the non-symmetric version, resulting in a system that can imitate demonstrated pick and place behavior using very few human demonstrations on a variety of imitation learning tasks.Comment: arXiv admin note: substantial text overlap with arXiv:2202.0940

EUDoptimizer: Assisting End Users in Composing IF-THEN Rules Through Optimization

Nowadays, several interfaces for end-user development (EUD) empower end users to jointly program the behavior of their smart devices and online services, typically through trigger-action rules. Despite their popularity, such interfaces often expose too much functionality and force the user to search among a large number of supported technologies disposed of confused grid menus. This paper contributes to the EUD with the aim of interactively assisting end users in composing IF-THEN rules with an optimizer in the loop. The goal, in particular, is to automatically redesign the layout of the EUD interfaces to facilitate the users in defining triggers and actions. For this purpose, we define a predictive model to characterize the composition of trigger-action rules on the basis of their final functionality, we adopt different optimization algorithms to explore the design space, and c) we present EUDoptimizer, the integration of our approach in IFTTT, one of the most popular EUD interfaces. We demonstrate that good layout solutions can be obtained in a reasonable amount of time. Furthermore, an empirical evaluation with 12 end users shows evidence that EUDoptimizer reduces the efforts needed to compose trigger-action rules

Varying the Explanatory Span: Scientific Explanation for Computer Simulations

This article aims to develop a new account of scientific explanation for computer simulations. To this end, two questions are answered: what is the explanatory relation for computer simulations? And what kind of epistemic gain should be expected? For several reasons tailored to the benefits and needs of computer simulations, these questions are better answered within the unificationist model of scientific explanation. Unlike previous efforts in the literature, I submit that the explanatory relation is between the simulation model and the results of the simulation. I also argue that our epistemic gain goes beyond the unificationist account, encompassing a practical dimension as well

Implementation of a low-cost photogrammetric methodology for 3D modelling of ceramic fragments

International audienceA simple and cheap tool has been developed for measuring shards of old ceramics, found in archaeological yards. It is based on a digital camera, and various photogrammetric and computer vision freeware completed by home-made software developments. The paper presents the equipment used for the acquisition of the images, and the processing software for the various steps. This software is mainly based on algorithms originating from computer vision community, and from more classical photogrammetry. Some intermediate results are presented, the final output of the present work being a very dense cloud of points describing the geometry of the surface of the shard, that may be post processed by many off-the-shelf drawing commercial software, depending on the needs of the archaeologists

Place Identity:How Far Have We Come in Exploring Its Meanings?

In order to synthesize the extensively studied place identities and their meanings, this paper reviews how researchers have conceived and deconstructed place identity. CiteSpace, a scientometric tool for visualizing and analyzing trends and patterns in scientific literature, is used to identify the active topics and new developments of publications in place identity. The data set input into CiteSpace consists of 1,011 bibliographic records retrieved from the core database of Web of Science with a title search of the articles published between 1985 and July 2019. The scientometric review reveals the extensive applications of place identity in various topics. Studies in this field experienced an active exploration in plural disciplines after 2000, and the hot area gradually concentrated on the discipline of humanities and social sciences after 2010 and shifted toward place marketing until now. A network of co-cited references identified seven dominant research clusters, of which the research on the influence of place identity on social actors' attitudes and behaviors is most prominent and the research on the effects of physical environment change on place identity captures the latest emerging area. Versatile meanings of place identity are witnessed in different clusters and articles of a cluster. These meanings are intertwined in shaping the knowledge base of thematic concentrations. To supplement the scientometric analysis, a deep survey on measuring methods and roles of place identity in the contents of academic articles was done to trace knowledge connections between different empirical understandings of place identity. Finally, this paper summarizes the meanings of place identity in four dimensions and in turn offers some suggestions for further research directions