2,384 research outputs found
Inside Job: Diagnosing Bluetooth Lower Layers Using Off-the-Shelf Devices
Bluetooth is among the dominant standards for wireless short-range
communication with multi-billion Bluetooth devices shipped each year. Basic
Bluetooth analysis inside consumer hardware such as smartphones can be
accomplished observing the Host Controller Interface (HCI) between the
operating system's driver and the Bluetooth chip. However, the HCI does not
provide insights to tasks running inside a Bluetooth chip or Link Layer (LL)
packets exchanged over the air. As of today, consumer hardware internal
behavior can only be observed with external, and often expensive tools, that
need to be present during initial device pairing. In this paper, we leverage
standard smartphones for on-device Bluetooth analysis and reverse engineer a
diagnostic protocol that resides inside Broadcom chips. Diagnostic features
include sniffing lower layers such as LL for Classic Bluetooth and Bluetooth
Low Energy (BLE), transmission and reception statistics, test mode, and memory
peek and poke
Enabling collaboration in virtual reality navigators
In this paper we characterize a feature superset for Collaborative
Virtual Reality Environments (CVRE), and derive a component
framework to transform stand-alone VR navigators into full-fledged
multithreaded collaborative environments. The contributions of our
approach rely on a cost-effective and extensible technique for
loading software components into separate POSIX threads for
rendering, user interaction and network communications, and adding a
top layer for managing session collaboration. The framework recasts
a VR navigator under a distributed peer-to-peer topology for scene
and object sharing, using callback hooks for broadcasting remote
events and multicamera perspective sharing with avatar interaction.
We validate the framework by applying it to our own ALICE VR
Navigator. Experimental results show that our approach has good
performance in the collaborative inspection of complex models.Postprint (published version
Throughput analysis of TCP congestion control algorithms in a cloud based collaborative virtual environment
Collaborative Virtual Environment (CVE) has
become popular in the last few years, this is because CVE is
designed to allow geographically distributed users to work
together over the network. In CVE the state of the virtual
objects is witnessing unprecedentant change. When a user
performs an action in CVE, the information of the action needs
to be transmitted to other users to maintain consistency in the
cooperative work. TCP is the most widely used protocol in the
design of CVE, and its throughput deteriorates in the network
with large delay. Gital et al, 2014 proposes a cloud based
architectural model for improving scalability and consistency
in CVE. Therefore, this paper aim at evaluating and
comparing the performance of different TCP variant (Tahoe,
Reno, New Reno, Vegas, SACK, Fack and Linux) with the
cloud based CVE architecture to determine the suitability of
each TCP variant for CVE. A comparative analysis between
the different TCP variants is presented in terms of throughput
verses elapse time, with increasing number of users in the
system. TCP with the cloud based model was found to be
effective, promising and robust for achieving consistency
requirement in CVE system
Performance analysis of cloud-based cve communication architecture in comparison with the traditional client server, p2p and hybrid models
Gital et al. (2014) proposed a cloud based
communication architecture for improving efficiency of
collaborative virtual environment (CVE) systems in
terms of Scalability and Consistency requirements. This
paper evaluates the performance of the proposed CVE
architecture. The metrics use for the evaluation is
response time. We compare the cloud-based architecture
to the traditional client server and peer-2–peer (P2P)
architecture. The comparison was implemented in the
CVE systems. The comparative simulation analysis of
the results suggested that the CVE architecture based on
cloud computing can significantly improve the
performance of the CVE system
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