Search results for "COD"
showing 10 items of 2985 documents
Optimization of the Relay Selection Scheme in Cooperative Retransmission Networks
2011
Cooperative MAC protocol design has attracted much attention recently thanks to the development of relaying techniques. In single-relay C-ARQ, the relay selection scheme cannot work efficiently in a dense network, due to high collision probability among different contending relays. In this paper, the throughput performance impairment from the collision is analysed in a typical network scenario. Thereby, we propose an optimized relay selection scheme aiming at maximizing system throughput by reducing collision probability. The throughput performance enhancement by the proposed optimal relay selection scheme is verified by simulations.
Use of H.264 real-time video encoding to reduce display wall system bandwidth consumption
2015
This paper compares the DXT and JPEG image compression techniques used in display wall solutions SAGE and DisplayCluster with hardware accelerated H.264 video encoding that is used in the display wall system developed by the authors of this paper. The obtained processing power usage and generated bandwidth measurements presented in this paper demonstrate that hardware accelerated H.264 encoding offers multiple benefits over software implemented H.264, DXT and JPEG.
Prediction of Disease–lncRNA Associations via Machine Learning and Big Data Approaches
2021
This chapter introduces long non-coding RNAs and their role in the occurrence and progress of diseases. The discovery of novel lncRNA-disease associations may provide valuable input to the understanding of disease mechanisms at the lncRNA level, as well as to the detection of biomarkers for disease diagnosis, treatment, prognosis, and prevention. Unfortunately, due to costs and time complexity, the number of possible disease-related lncRNAs verified by traditional biological experiments is very limited. Computational approaches for the prediction of potential disease-lncRNA associations can effectively decrease the time and cost of biological experiments. We first review the main computatio…
Detection of Duplicated Regions in Tampered Digital Images by Bit-Plane Analysis
2009
In this paper we present a new method for searching duplicated areas in a digital image. The goal is to detect if an image has been tampered by a copy-move process. Our method works within a convenient domain. The image to be analyzed is decomposed in its bit-plane representation. Then, for each bitplane, block of bits are encoded with an ASCII code, and a sequence of strings is analyzed rather than the original bit-plane. The sequence is lexicographically sorted and similar groups of bits are extracted as candidate areas, and passed to the following plane to be processed. Output of the last planes indicates if, and where, the image has been altered.
Current characterisation for ultra low power wireless body area networks
2010
The emerging area of body area networks (BAN) imposes challenging requirements on hardware and software to achieve the desired lifetimes for certain devices such as long term medical implants. In this paper, we propose a novel approach to the measurement and characterisation of the energy consumption of BAN devices. The approach uses a low cost energy auditing circuit and addresses the problem of accurately measuring low-level current consumption. This new technique will allow precise and analytical measurements of systems and components in terms of energy. This will help circuit designers minimise power consumption in BAN devices. Software engineers might use this approach to validate and …
Performance Analysis of M-Ary PSK Modulation Schemes over Multiple Double Rayleigh Fading Channels with EGC in Cooperative Networks
2010
This article studies the performance of M-ary phase shift keying (PSK) modulation schemes over mobile-to-mobile (M2M) fading channels with equal gain combining (EGC) in cooperative networks. The frequency-nonselective M2M fading channels are modeled assuming non-line-of-sight (NLOS) propagation conditions. Furthermore, a dual-hop amplify-and-forward relay type cooperative network is taken into consideration here. It is assumed that K diversity branches are present between the source mobile station and the destination mobile station via K mobile relays. The performance of M-ary PSK modulation schemes is analyzed by evaluating the average bit error probability (BEP). We have derived a simple …
Multi-Antenna Covert Communication With Jamming in the Presence of a Mobile Warden
2021
Covert communication can hide the information transmission process from the warden to prevent adversarial eavesdropping. However, it becomes challenging when the warden can move. In this paper, we propose a covert communication scheme against a mobile warden, which maximizes the connectivity throughput between a multi-antenna transmitter and a full-duplex jamming receiver with the covert outage probability (COP) limit. First, we analyze the monotonicity of the COP to obtain the optimal location the warden can move. Then, under this worst situation, we optimize the transmission rate, the transmit power and the jamming power of covert communication to maximize the connection throughput. This …
Repair Mechanisms for Broadcast Transmissions in Hybrid Cellular & DVB-H Systems
2006
This paper proposes a framework for investigating potential infrastructure cost savings in hybrid cellular and DVB- H systems by performing efficient error repair of broadcast transmissions. The main idea is to reuse as much as possible the existing network infrastructure to provide mobile TV services. The cellular system is not only employed to collect information, but also to send repair data to the users whose conditions are temporarily affected by noise, interference and fading. To enable an easy and efficient implementation of the repair mechanisms we adopt the use of application layer - forward error correction (AL-FEC) with digital fountain coding.
Application Layer FEC for Mobile TV Delivery in IP Datacast Over DVB-H Systems
2009
In this paper we investigate the potential gain that can be obtained in DVB-H using application layer forward error correction (AL-FEC) to perform a multi-burst protection of the transmission for improving the reception of streaming services for mobile terminals. Compared to the conventional approach with link layer multi protocol encapsulation FEC (MPE-FEC), this technique allows to increase the robustness of the DVB-H transmission not only as a function of the capacity devoted for error repair (FEC overhead), but also as a function of the number of bursts jointly encoded. The main drawback of this approach is an increase of the network latency, that can be translated into a larger service…
Learning Flow-Based Feature Warping for Face Frontalization with Illumination Inconsistent Supervision
2020
Despite recent advances in deep learning-based face frontalization methods, photo-realistic and illumination preserving frontal face synthesis is still challenging due to large pose and illumination discrepancy during training. We propose a novel Flow-based Feature Warping Model (FFWM) which can learn to synthesize photo-realistic and illumination preserving frontal images with illumination inconsistent supervision. Specifically, an Illumination Preserving Module (IPM) is proposed to learn illumination preserving image synthesis from illumination inconsistent image pairs. IPM includes two pathways which collaborate to ensure the synthesized frontal images are illumination preserving and wit…