A-Scan2BIM: Assistive Scan to Building Information Modeling

This paper proposes an assistive system for architects that converts a large-scale point cloud into a standardized digital representation of a building for Building Information Modeling (BIM) applications. The process is known as Scan-to-BIM, which requires many hours of manual work even for a single building floor by a professional architect. Given its challenging nature, the paper focuses on helping architects on the Scan-to-BIM process, instead of replacing them. Concretely, we propose an assistive Scan-to-BIM system that takes the raw sensor data and edit history (including the current BIM model), then auto-regressively predicts a sequence of model editing operations as APIs of a professional BIM software (i.e., Autodesk Revit). The paper also presents the first building-scale Scan2BIM dataset that contains a sequence of model editing operations as the APIs of Autodesk Revit. The dataset contains 89 hours of Scan2BIM modeling processes by professional architects over 16 scenes, spanning over 35,000 m^2. We report our system's reconstruction quality with standard metrics, and we introduce a novel metric that measures how natural the order of reconstructed operations is. A simple modification to the reconstruction module helps improve performance, and our method is far superior to two other baselines in the order metric. We will release data, code, and models at a-scan2bim.github.io.Comment: BMVC 2023, order evaluation updated after fixing evaluation bu

Behavioral control and changes in brain activity of honeybee during flapping

Abstract Introduction Insect cyborg is a kind of novel robot based on insect–machine interface and principles of neurobiology. The key idea is to stimulate live insects by specific stimuli; thus, the flight trajectory of insects could be controlled as anticipated. However, the neuroregulatory mechanism of insect flight has not been elucidated completely at present. Methods To explore the neuro‐mechanism of insect flight behaviors, a series of electrical stimulation was applied on the optic lobes of semi‐constrained honeybees. Times of flight initiation, flapping frequency, and duration were recorded by a high‐speed camera. In addition, flapping and steering initiation experiments of the cyborg honeybee were verified. Moreover, series of local field potential signals of optic lobes during flapping were collected, pre‐processed to remove baseline wander and DC components, then analyzed by power spectrum estimation. Results A quantitative optimization method and optimal stimulation parameters of flight initiation were presented. Stimulation results showed that the flapping duration differed greatly while the flapping frequency varied with little difference among different individuals. Moreover, there was always a fluctuation peak around 20–30 Hz in power spectral density (PSD) curves during flapping, distinguishing from calm state, which indicated some brain activity changes during flapping. Conclusions Our study presented a range of relatively optimal electrical parameters to initiate honeybee flight behavior. Meanwhile, the regularity of flapping duration and flapping frequency under electrical stimulations with different parameters were given. The feasibility of controlling a honeybee's flight behavior by brain electrical stimulation was verified through the flapping and steering initiation experiment of honeybees under semi‐constrained state. PSD fluctuations reflected changes in brain activity during flapping and that those fluctuation characteristics at the specific frequency band could be sensitive determinants to distinguish whether the honeybee was flying or not, which benefits our understanding of honeybee's flapping behavior and furthers the study of honeybee cyborgs

Nectar Feeding by a Honey Bee’s Hairy Tongue: Morphology, Dynamics, and Energy-Saving Strategies

Most flower-visiting insects have evolved highly specialized morphological structures to facilitate nectar feeding. As a typical pollinator, the honey bee has specialized mouth parts comprised of a pair of galeae, a pair of labial palpi, and a glossa, to feed on the nectar by the feeding modes of lapping or sucking. To extensively elucidate the mechanism of a bee’s feeding, we should combine the investigations from glossa morphology, feeding behaviour, and mathematical models. This paper reviews the interdisciplinary research on nectar feeding behaviour of honey bees ranging from morphology, dynamics, and energy-saving strategies, which may not only reveal the mechanism of nectar feeding by honey bees but inspire engineered facilities for microfluidic transport

Barbs Facilitate the Helical Penetration of Honeybee (<i>Apis mellifera ligustica</i>) Stingers

<div><p>The stinger is a very small and efficient device that allows honeybees to perform two main physiological activities: repelling enemies and laying eggs for reproduction. In this study, we explored the specific characteristics of stinger penetration, where we focused on its movements and the effects of it microstructure. The stingers of Italian honeybees (<i>Apis mellifera ligustica</i>) were grouped and fixed onto four types of cubic substrates, before pressing into different substrates. The morphological characteristics of the stinger cross-sections were analyzed before and after penetration by microscopy. Our findings suggest that the honeybee stinger undergoes helical and clockwise rotation during penetration. We also found that the helical penetration of the stinger is associated directly with the spiral distribution of the barbs, thereby confirming that stinger penetration involves an advanced microstructure rather than a simple needle-like apparatus. These results provide new insights into the mechanism of honeybee stinger penetration.</p></div

Rotation angles of the stinger shafts.

<p>The stinger samples marked with <i>S</i> and the hair samples marked with <i>H</i> were used for comparison. The two adjacent bars show the rotation angles of the honeybee stingers (left side) and the hair samples (right side). In each type of substrate, the rotation angle of the hair was very small, which demonstrated that the instrument had no significant effect on the rotation angle during pushing. The experimental observations confirmed the existence of rotation during the stinging process. Furthermore, we found that the rotation angle was associated with the stiffness of the substrate.</p

Anatomy of the honeybee’s stinger apparatus.

<p>The stinger resides in the sting chamber inside the last abdominal segment (not to scale). The sting apparatus mainly comprises the protractor/retractor muscles, the bulb, the stinger, and the venom sac. The protractor muscles drive the stinger to penetrate the wound and the retractor muscles are used in the reverse manner to pull the stinger back into the sting chamber. During penetration, the venom is pumped into the stinger from the bulb, which is also known as the venom reservoir.</p

Preparation of the stinger samples and the experiments.

<p>The stingers of worker bees were collected and separated into two groups. (1) The first group of stingers were placed onto the polymethyl methacrylate panel using drops of 15% polyvinyl alcohol (0.1 µL), and they were then placed vertically on the substrates (agar, silica gel, soft rubber and paraffin wax), before pushing the stingers into the substrates at a velocity of 6 mm mm/s using the positioner. The positioner, also called the precision position platform, is a machine that is able to push tiny appendages accurately into the substrates following the planned kinematics, for instance the preset average velocity, the total displacement even the acceleration. (2) The microstructures of the second group of stingers were observed using an environmental scanning electron microscope.</p

Environmental scanning electron microscope images of the stinger.

<p>(A) The needle-like sting, venom sac, and related glands. The stinger is activated by the muscles to penetrate the skin of the victim. (B) Barbs along the axial direction of the sting. The solid line in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0103823#pone-0103823-g003" target="_blank">Figure 3(b)</a> is the axis of the sting which is obtained by connecting the tip of the stinger and the midpoint of the stinger root. The stinger of <i>Apis mellifera ligustica</i> has two rows of barbs, each of which comprises about 10 barbs. The angle between the rows of barbs and the axis of the stinger shaft was around 8–9°, according to observations based on 10 samples. The row of barbs was found to form a right-handed helix. (C) Magnified view of the barbs. Seven barbs are marked with the notations 1–1′, 2–2′, etc. Note that the angles of the tips were 90.33°, 89.62°, 80.31°, 72.13°, 72.36°, 59.63°, and 46.19°, thereby demonstrating that the barbs were relatively sharper near the tip of the stinger. (D) Magnified view of two rows of barbs. Viewed in the axial direction, the angles between the two rows of barbs were about 95°.</p