2,023 research outputs found
Low-cost multipurpose sensor network integrated with iot and webgis for fire safety concerns
Fire emergencies cause severe damage to Brazilian federal universities. An appropriate and efficient tool to prevent or detect such events early is multisensory networks from the Internet of Things (IoT). In this study, we present the stages of development of a WebGIS system which integrates the IoT that allows the detection and helps manage such incidents. The approach consists of a network of multipurpose sensors that can identify different sources of fire hazards. If a potential source is registered, information about environmental conditions is transmitted in real-time to the system. Depending on the severity level, an alert is issued to WebGIS. Location is represented on a map. The entire system consists of single-board devices. Software components are based on open-source tools. The whole network only needs little power and, therefore, theoretically, could be carried out as an autonomous system powered by batteries. The entire system has been tested with flame, temperature, gas, smoke, and humidity sensors. The experiments allowed us to show its potential, formulate recommendations and indications for future studies
Reactive Navigation in Partially Known Non-Convex Environments
This paper presents a provably correct method for robot navigation in 2D environments cluttered with familiar but unexpected non-convex, star-shaped obstacles as well as completely unknown, convex obstacles. We presuppose a limited range onboard sensor, capable of recognizing, localizing and (leveraging ideas from constructive solid geometry) generating online from its catalogue of the familiar, non-convex shapes an implicit representation of each one. These representations underlie an online change of coordinates to a completely convex model planning space wherein a previously developed online construction yields a provably correct reactive controller that is pulled back to the physically sensed representation to generate the actual robot commands. We extend the construction to differential drive robots, and suggest the empirical utility of the proposed control architecture using both formal proofs and numerical simulations.
For more information: Kod*la
Scraping the Social? Issues in live social research
What makes scraping methodologically interesting for social and cultural research? This paper seeks to contribute to debates about digital social research by exploring how a âmedium-specificâ technique for online data capture may be rendered analytically productive for social research. As a device that is currently being imported into social research, scraping has the capacity to re-structure social research, and this in at least two ways. Firstly, as a technique that is not native to social research, scraping risks to introduce âalienâ methodological assumptions into social research (such as an pre-occupation with freshness). Secondly, to scrape is to risk importing into our inquiry categories that are prevalent in the social practices enabled by the media: scraping makes available already formatted data for social research. Scraped data, and online social data more generally, tend to come with âexternalâ analytics already built-in. This circumstance is often approached as a âproblemâ with online data capture, but we propose it may be turned into virtue, insofar as data formats that have currency in the areas under scrutiny may serve as a source of social data themselves. Scraping, we propose, makes it possible to render traffic between the object and process of social research analytically productive. It enables a form of âreal-timeâ social research, in which the formats and life cycles of online data may lend structure to the analytic objects and findings of social research. By way of a conclusion, we demonstrate this point in an exercise of online issue profiling, and more particularly, by relying on Twitter to profile the issue of âausterityâ. Here we distinguish between two forms of real-time research, those dedicated to monitoring live content (which terms are current?) and those concerned with analysing the liveliness of issues (which topics are happening?)
Unified command and control for heterogeneous marine sensing networks
Successful command and control (C2) of autonomous vehicles poses challenges that are unique to the marine environment, primarily highly restrictive acoustic communications throughput. To address this, the Unified C2 architecture presented here uses a highly compressed short message encoding scheme (Dynamic Compact Control Language or DCCL) to transfer commands and receive vehicle status. DCCL is readily reconfigurable to provide the flexibility needed to change commands on short notice. Furthermore, operation of multiple types of vehicles requires a C2 architecture that is both scalable and flexible to differences among platform hardware and abilities. The Unified C2 architecture uses the MOOS-IvP autonomy system to act as a âbackseat driverâ of the vehicle. This provides a uniform interface to the control system on all the vehicles. Also, a hierarchical configuration system is used to allow single changes in configuration to propagate to all vehicles in operation. Status data from all vehicles are displayed visually using Google Earth, which also allows a rapid meshing of data from other sources (sensors, automatic identification system, radar, satellites) from within, as well as outside of, the MOOS-IvP architecture. Results are presented throughout from the CCLNET08, SQUINT08, GLINT08, GLINT09, SWAMSI09, and DURIP09 experiments involving robotic marine autonomous surface craft (ASCs) and Bluefin, OceanServer, and NATO Undersea Research Centre (NURC) autonomous underwater vehicles (AUVs).United States. Office of Naval Research (Grant N00014-1-08-1-0013)United States. Office of Naval Research (Grant N00014-1-08-1-0011
The Transitivity of Trust Problem in the Interaction of Android Applications
Mobile phones have developed into complex platforms with large numbers of
installed applications and a wide range of sensitive data. Application security
policies limit the permissions of each installed application. As applications
may interact, restricting single applications may create a false sense of
security for the end users while data may still leave the mobile phone through
other applications. Instead, the information flow needs to be policed for the
composite system of applications in a transparent and usable manner. In this
paper, we propose to employ static analysis based on the software architecture
and focused data flow analysis to scalably detect information flows between
components. Specifically, we aim to reveal transitivity of trust problems in
multi-component mobile platforms. We demonstrate the feasibility of our
approach with Android applications, although the generalization of the analysis
to similar composition-based architectures, such as Service-oriented
Architecture, can also be explored in the future
Sim2Real Neural Controllers for Physics-based Robotic Deployment of Deformable Linear Objects
Deformable linear objects (DLOs), such as rods, cables, and ropes, play
important roles in daily life. However, manipulation of DLOs is challenging as
large geometrically nonlinear deformations may occur during the manipulation
process. This problem is made even more difficult as the different deformation
modes (e.g., stretching, bending, and twisting) may result in elastic
instabilities during manipulation. In this paper, we formulate a physics-guided
data-driven method to solve a challenging manipulation task -- accurately
deploying a DLO (an elastic rod) onto a rigid substrate along various
prescribed patterns. Our framework combines machine learning, scaling analysis,
and physical simulations to develop a physics-based neural controller for
deployment. We explore the complex interplay between the gravitational and
elastic energies of the manipulated DLO and obtain a control method for DLO
deployment that is robust against friction and material properties. Out of the
numerous geometrical and material properties of the rod and substrate, we show
that only three non-dimensional parameters are needed to describe the
deployment process with physical analysis. Therefore, the essence of the
controlling law for the manipulation task can be constructed with a
low-dimensional model, drastically increasing the computation speed. The
effectiveness of our optimal control scheme is shown through a comprehensive
robotic case study comparing against a heuristic control method for deploying
rods for a wide variety of patterns. In addition to this, we also showcase the
practicality of our control scheme by having a robot accomplish challenging
high-level tasks such as mimicking human handwriting, cable placement, and
tying knots.Comment: YouTube video: https://youtu.be/OSD6dhOgyMA?feature=share
- âŠ