11,410 research outputs found
Deterministic secure quantum communication with and without entanglement
We present a protocol for sending a message over a quantum channel with
different layers of security that will prevent an eavesdropper from deciphering
the message without being detected. The protocol has two versions where the
bits are encoded in either pairs of entangled photons or separate photons.
Unlike many other protocols, it requires a one-way, rather than a two-way,
quantum channel and does not require a quantum memor. A quantum key is used to
encrypt the message and both the key and the message are sent over the quantum
channle with the same quantum encoding technique. The key is sent only if no
eavesdropper is detected.Comment: 9 pages, 3 figures. Major changes in section 3 and 4. Accepted for
publication in Physica Script
Affect and believability in game characters:a review of the use of affective computing in games
Virtual agents are important in many digital environments. Designing a character that highly engages users in terms of interaction is an intricate task constrained by many requirements. One aspect that has gained more attention recently is the effective dimension of the agent. Several studies have addressed the possibility of developing an affect-aware system for a better user experience. Particularly in games, including emotional and social features in NPCs adds depth to the characters, enriches interaction possibilities, and combined with the basic level of competence, creates a more appealing game. Design requirements for emotionally intelligent NPCs differ from general autonomous agents with the main goal being a stronger player-agent relationship as opposed to problem solving and goal assessment. Nevertheless, deploying an affective module into NPCs adds to the complexity of the architecture and constraints. In addition, using such composite NPC in games seems beyond current technology, despite some brave attempts. However, a MARPO-type modular architecture would seem a useful starting point for adding emotions
All-Digital Self-interference Cancellation Technique for Full-duplex Systems
Full-duplex systems are expected to double the spectral efficiency compared
to conventional half-duplex systems if the self-interference signal can be
significantly mitigated. Digital cancellation is one of the lowest complexity
self-interference cancellation techniques in full-duplex systems. However, its
mitigation capability is very limited, mainly due to transmitter and receiver
circuit's impairments. In this paper, we propose a novel digital
self-interference cancellation technique for full-duplex systems. The proposed
technique is shown to significantly mitigate the self-interference signal as
well as the associated transmitter and receiver impairments. In the proposed
technique, an auxiliary receiver chain is used to obtain a digital-domain copy
of the transmitted Radio Frequency (RF) self-interference signal. The
self-interference copy is then used in the digital-domain to cancel out both
the self-interference signal and the associated impairments. Furthermore, to
alleviate the receiver phase noise effect, a common oscillator is shared
between the auxiliary and ordinary receiver chains. A thorough analytical and
numerical analysis for the effect of the transmitter and receiver impairments
on the cancellation capability of the proposed technique is presented. Finally,
the overall performance is numerically investigated showing that using the
proposed technique, the self-interference signal could be mitigated to ~3dB
higher than the receiver noise floor, which results in up to 76% rate
improvement compared to conventional half-duplex systems at 20dBm transmit
power values.Comment: Submitted to IEEE Transactions on Wireless Communication
On Phase Noise Suppression in Full-Duplex Systems
Oscillator phase noise has been shown to be one of the main performance
limiting factors in full-duplex systems. In this paper, we consider the problem
of self-interference cancellation with phase noise suppression in full-duplex
systems. The feasibility of performing phase noise suppression in full-duplex
systems in terms of both complexity and achieved gain is analytically and
experimentally investigated. First, the effect of phase noise on full-duplex
systems and the possibility of performing phase noise suppression are studied.
Two different phase noise suppression techniques with a detailed complexity
analysis are then proposed. For each suppression technique, both free-running
and phase locked loop based oscillators are considered. Due to the fact that
full-duplex system performance highly depends on hardware impairments,
experimental analysis is essential for reliable results. In this paper, the
performance of the proposed techniques is experimentally investigated in a
typical indoor environment. The experimental results are shown to confirm the
results obtained from numerical simulations on two different experimental
research platforms. At the end, the tradeoff between the required complexity
and the gain achieved using phase noise suppression is discussed.Comment: Published in IEEE transactions on wireless communications on
October-2014. Please refer to the IEEE version for the most updated documen
Effect of Super Resolution on High Dimensional Features for Unsupervised Face Recognition in the Wild
Majority of the face recognition algorithms use query faces captured from
uncontrolled, in the wild, environment. Often caused by the cameras limited
capabilities, it is common for these captured facial images to be blurred or
low resolution. Super resolution algorithms are therefore crucial in improving
the resolution of such images especially when the image size is small requiring
enlargement. This paper aims to demonstrate the effect of one of the
state-of-the-art algorithms in the field of image super resolution. To
demonstrate the functionality of the algorithm, various before and after 3D
face alignment cases are provided using the images from the Labeled Faces in
the Wild (lfw). Resulting images are subject to testing on a closed set face
recognition protocol using unsupervised algorithms with high dimension
extracted features. The inclusion of super resolution algorithm resulted in
significant improved recognition rate over recently reported results obtained
from unsupervised algorithms
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