Virtual Net: a Decentralized Architecture for Interaction in Mobile Virtual Worlds

With the development of mobile technology, mobile virtual worlds have attracted massive users. To improve scalability, a peer-to-peer virtual world provides the solution to accommodate more users without increasing hardware investment. In mobile settings, however, existing P2P solutions are not applicable due to the unreliability of mobile devices and the instability of mobile networks. To address the issue, a novel infrastructure model, called Virtual Net, is proposed to provide fault-tolerance in managing user content and object state. In this paper, the key problem, namely object state update, is resolved to maintain state consistency and high interaction responsiveness. This work is important in implementing a scalable mobile virtual world

Peer-to-peer update dissemination in browser-based networked virtual environments.

PhD ThesisNetworked Virtual Environments (NVEs) have always imposed strict requirements on architectures for update dissemination (UD). Clients must maintain views that are as synchronous and consistent as possible in order to achieve a level of user experience that is tolerable for the user. In recent times, the web browser has become a viable platform on which to deploy these NVEs. Doing so adds another layer of challenges however. There is a distinct need for systems that adapt to these constraints and exploit the characteristics of this new context to achieve reliably high consistency between users for a range of use cases. A promising approach is to carry forward the rich body of past research in peer-to-peer (P2P) networks and apply this to the problem of UD in NVEs under the constraints of a web browser. Making NVEs scalable through P2P networks is not a new concept, however previous work has always been either too specific to a certain kind of NVE, or made performance trade-offs that especially cannot work in a browser context. Furthermore, in previous work on P2P NVEs, UD has always taken the backseat compared to object management and distributed neighbour selection. The evaluation of these UD systems have as a result been one-dimensional and overly simplifying. In this work, we begin by surveying past UD solutions and evaluation methodologies. We then capture NVE, browser, and network constraints, aided by the analysis of a rich dataset of NVE network traces that we have collected, and draw out key observations and challenges to develop the requirements for a feasible UD system. From there, we illustrate the design and implementation of our P2P UD system for NVEs in great detail, augmenting our system with novel architectural insights from the Software-Defined Networking (SDN) space. Finally, we evaluate our system under a range of workloads, test environments, and performance metrics to demonstrate that we have overcome these challenges, as well as compare our method to other existing methods, which we have also implemented and tested. We hope that our contributions in research and resources (such as our taxonomies, NVE analysis, UD system, browser library, workload datasets, and a benchmarking framework) bring more structure as well as research and development opportunities to a relatively niche sub-field

Air Traffic Management Abbreviation Compendium

As in all fields of work, an unmanageable number of abbreviations are used today in aviation for terms, definitions, commands, standards and technical descriptions. This applies in general to the areas of aeronautical communication, navigation and surveillance, cockpit and air traffic control working positions, passenger and cargo transport, and all other areas of flight planning, organization and guidance. In addition, many abbreviations are used more than once or have different meanings in different languages. In order to obtain an overview of the most common abbreviations used in air traffic management, organizations like EUROCONTROL, FAA, DWD and DLR have published lists of abbreviations in the past, which have also been enclosed in this document. In addition, abbreviations from some larger international projects related to aviation have been included to provide users with a directory as complete as possible. This means that the second edition of the Air Traffic Management Abbreviation Compendium includes now around 16,500 abbreviations and acronyms from the field of aviation

Humanoid Robots

For many years, the human being has been trying, in all ways, to recreate the complex mechanisms that form the human body. Such task is extremely complicated and the results are not totally satisfactory. However, with increasing technological advances based on theoretical and experimental researches, man gets, in a way, to copy or to imitate some systems of the human body. These researches not only intended to create humanoid robots, great part of them constituting autonomous systems, but also, in some way, to offer a higher knowledge of the systems that form the human body, objectifying possible applications in the technology of rehabilitation of human beings, gathering in a whole studies related not only to Robotics, but also to Biomechanics, Biomimmetics, Cybernetics, among other areas. This book presents a series of researches inspired by this ideal, carried through by various researchers worldwide, looking for to analyze and to discuss diverse subjects related to humanoid robots. The presented contributions explore aspects about robotic hands, learning, language, vision and locomotion

The Fifth NASA Symposium on VLSI Design

The fifth annual NASA Symposium on VLSI Design had 13 sessions including Radiation Effects, Architectures, Mixed Signal, Design Techniques, Fault Testing, Synthesis, Signal Processing, and other Featured Presentations. The symposium provides insights into developments in VLSI and digital systems which can be used to increase data systems performance. The presentations share insights into next generation advances that will serve as a basis for future VLSI design

AOI cast by Tolerance Based Compass Routing in Distributed Virtual Environments

This paper presents an Area of Interest(AOI)-cast strategy for P2P Distributed Virtual Environment (DVE) which exploits a Delaunay Triangulation of the DVE to define a compass-based routing algorithm. A set of formal results for circular AOI is presented. Inconsistencies between local views of different peers due to the network latency are faced by introducing a tolerance threashold in the compass routing

LIPIcs, Volume 277, GIScience 2023, Complete Volume

LIPIcs, Volume 277, GIScience 2023, Complete Volum