30,316 research outputs found
Implementation of UAV Coordination Based on a Hierarchical Multi-UAV Simulation Platform
In this paper, a hierarchical multi-UAV simulation platform,called XTDrone,
is designed for UAV swarms, which is completely open-source 4 . There are six
layers in XTDrone: communication, simulator,low-level control, high-level
control, coordination, and human interac-tion layers. XTDrone has three
advantages. Firstly, the simulation speedcan be adjusted to match the computer
performance, based on the lock-step mode. Thus, the simulations can be
conducted on a work stationor on a personal laptop, for different purposes.
Secondly, a simplifiedsimulator is also developed which enables quick algorithm
designing sothat the approximated behavior of UAV swarms can be observed
inadvance. Thirdly, XTDrone is based on ROS, Gazebo, and PX4, andhence the
codes in simulations can be easily transplanted to embeddedsystems. Note that
XTDrone can support various types of multi-UAVmissions, and we provide two
important demos in this paper: one is aground-station-based multi-UAV
cooperative search, and the other is adistributed UAV formation flight,
including consensus-based formationcontrol, task assignment, and obstacle
avoidance.Comment: 12 pages, 10 figures. And for the, see
https://gitee.com/robin_shaun/XTDron
A game-based approach to the teaching of object-oriented programming languages
Students often have difficulties when trying to understand the concepts of object-oriented programming
(OOP). This paper presents a contribution to the teaching of OOP languages through a game-oriented
approach based on the interaction with tangible user interfaces (TUIs). The use of a specific type of
commercial distributed TUI (Sifteo cubes), in which several small physical devices have sensing, wireless
communication and user-directed output capabilities, is applied to the teaching of the C# programming
language, since the operation of these devices can be controlled by user programs written in C#. For our
experiment, we selected a sample of students with a sufficient knowledge about procedural programming,
which was divided into two groups: The first one had a standard introductory C# course, whereas
the second one had an experimental C# course that included, in addition to the contents of the previous
one, two demonstration programs that illustrated some OOP basic concepts using the TUI features.
Finally, both groups completed two tests: a multiple-choice exam for evaluating the acquisition of basic
OOP concepts and a C# programming exercise. The analysis of the results from the tests indicates that the
group of students that attended the course including the TUI demos showed a higher interest level (i.e.
they felt more motivated) during the course exposition than the one that attended the standard introductory
C# course. Furthermore, the students from the experimental group achieved an overall better
mark. Therefore, we can conclude that the technological contribution of Sifteo cubes â used as a
distributed TUI by which OOP basic concepts are represented in a tangible and a visible way â to the
teaching of the C# language has a positive influence on the learning of this language and such basic
concepts
The European Public(s) and its Problems
I present three versions âGrimm, Offe and Streeckâof a general argument that is often used to establish that the EU-institutions meets a legitimacy-disabling condition, the so called âno demosâ argument (II), embedding them in the context of the notorious âdemocratic deficitâ suspicions against the legal system and practice of the EU (I). After examining the logical structure behind the no-demos intuition considered as an argument (III), I present principled reasons by Möllers and Habermas that show why the âno demosâ argument fails to have bite in discussions of the legitimacy and status of the supranational level in the multi-level EU-architecture. These are complemented by another principled reason arising from John Deweyâs conception of the âpublicâ as a clearer alternative for the âpopularâ requirement of democratic legitimation (IV). I conclude that all three conceptions together suggest that the hunt after pre-politically existing peoples as foundations of democratic legitimacy expresses no more than methodological nationalism without any footing in the material and conceptual requirements of democratic legitimation. Given the absence of a principled problem with the legitimacy of the priority and interference of supranational EU-law in the national legal and political orders, there are thus also no principled reasons to abandon or discredit the European project in the absence of a European nation or society
Distributed earth model/orbiter simulation
Distributed Earth Model/Orbiter Simulation (DEMOS) is a network based application developed for the UNIX environment that visually monitors or simulates the Earth and any number of orbiting vehicles. Its purpose is to provide Mission Control Center (MCC) flight controllers with a visually accurate three dimensional (3D) model of the Earth, Sun, Moon and orbiters, driven by real time or simulated data. The project incorporates a graphical user interface, 3D modelling employing state-of-the art hardware, and simulation of orbital mechanics in a networked/distributed environment. The user interface is based on the X Window System and the X Ray toolbox. The 3D modelling utilizes the Programmer's Hierarchical Interactive Graphics System (PHIGS) standard and Raster Technologies hardware for rendering/display performance. The simulation of orbiting vehicles uses two methods of vector propagation implemented with standard UNIX/C for portability. Each part is a distinct process that can run on separate nodes of a network, exploiting each node's unique hardware capabilities. The client/server communication architecture of the application can be reused for a variety of distributed applications
An Impossible object? Ecological Democracy after the Anthropocene
El paper se pregunta en quĂ© medida la democracia -o sea, una democracia ecolĂłgica- puede ocuparse del Antropoceno, la nueva era geolĂłgica que describe una masiva penetraciĂłn humana en los sistemas naturales.Universidad de MĂĄlaga. Campus de Excelencia AndalucĂa Tec
The effect of WWW document structure on students' information retrieval
This experiment investigated the effect the structure of a WWW document has on the amount of information retained by a reader. Three structures common on the Internet were tested: one long page; a table of contents leading to individual sections; and short sections of text on separate pages with revision questions. Participants read information structured in one of these ways and were then tested on recall of that information. A further experiment investigated the effect that 'browsing' - moving between pages - has on retrieval. There was no difference between the structures for overall amount of information retained. The single page version was best for recall of facts, while the short sections of text with revision questions led to the most accurate inferences from the material. Browsing on its own had no significant impact on information retrieval. Revision questions rather than structure per se were therefore the key factor
Creativity and the experts: New Labour, think tanks, and the policy process
This article explores the role of expertise in public debate on creative industries policy in the United Kingdom. The first section gives an overview of the emergence of expertise in government and the rise of think tanks, locating this within a wider sociology of the intellectuals. It discusses the development of New Labour expertise in response to that of Thatcherite Conservatism in the battle to dominate public policy agendas. The second section illustrates the growth of the New Labour "policy generation" and the emergence of a cohort of experts in the fields of media, communications, and culture and discusses routes taken by them into government. The final section, based on interviews, discusses the power plays behind New Labour policy making in the creative industries field. It considers the impact of ministerial changes on the policy process, illustrates how interdepartmental rivalries introduce complexity and demonstrates how civil service expertise may be mobilised to neutralise that of outside experts. The conclusion addresses the implications of this analysis
- âŠ