Sajid Nazir

Expanding Window Random Linear Codes for data partitioned H.264 video transmission over DVB-H network

Rateless codes can be advantageously used to provide Application Layer Forward Error Correction (AL-FEC) with a distinct advantage that an infinite number of packets can be generated on the fly from the source packets. For heterogeneous users and/or variable channel conditions, significant adaptation features and improvement in the video quality can be achieved by partitioning the video data into different priority classes. Such partitioned data can be unequally protected using appropriate FEC scheme based on its contribution to video reconstruction. Expanding Window Random Linear Codes (EW RLC) are a simple unequal error protection fountain coding scheme which can adapt to the prioritized data transmission. In this paper, EW RLC are proposed for broadcasting the H.264/Advanced video coding partitioned with the data partitioning feature. The results show viability of the EW RLC for multimedia broadcast applications to suit different data rates and channel conditions.

Performance evaluation of Raptor and Random Linear Codes for H.264/AVC video transmission over DVB-H networks

Application Layer Forward Error Correction (AL)-FEC is increasingly being employed in the emerging wireless multimedia applications, where the multimedia data is sent along with repair data that can be used at the receiver to recover any losses. Raptor codes and Random Linear Codes (RLC) have emerged as promising rateless coding solutions. The DVB-H standard has adopted Raptor codes for IP datacasting, whereas for real-time communications, Reed-Solomon (RS) codes are used as link-layer FEC. This study compares the performance of Raptor codes and RLC for sending the H.264/AVC compressed video traffic over the DVB-H network. The simulations are performed using error traces depicting physical-layer Transport Stream (TS) packet losses in DVB-H. The study highlights the possibility of using RLC for the AL-FEC by selectively configuring codes for optimum performance.

Unequal error protection for data partitioned H.264/AVC video broadcasting

Application Layer Forward Error Correction (AL-FEC) is becoming a popular addition to protocols for real-time video delivery over IP-based wireless networks. In particular, rateless codes are identified as suitable solution for AL-FEC due to their flexibility and capacity-approaching performance. Since each part of video data is not equally important for video reconstruction, it is beneficial to group it based on its importance, and then provide different degree of protection using Unequal Error Protection (UEP). Data partitioning (DP) is one such low-cost feature in H.264/AVC enabling partitioning of video data based on its importance. We propose schemes for the DP H.264/AVC video transmission using Raptor and Random Linear Codes (RLC) and investigate their performance as AL-FEC solutions in Digital Video Broadcasting. We provide comparisons between optimized Non-Overlapping Window RLC and Expanding Window (EW) RLC, which are two effective UEP RLC strategies. The results using realistic channel traces show viability of the EW RLC as a promising solution for multimedia broadcast applications.

Assessing and augmenting SCADA cyber security: A survey of techniques

SCADA systems monitor and control critical infrastructures of national importance such as power generation and distribution, water supply, transportation networks, and manufacturing facilities. The pervasiveness, miniaturisations and declining costs of internet connectivity have transformed these systems from strictly isolated to highly interconnected networks. The connectivity provides immense benefits such as reliability, scalability and remote connectivity, but at the same time exposes an otherwise isolated and secure system, to global cyber security threats. This inevitable transformation to highly connected systems thus necessitates effective security safeguards to be in place as any compromise or downtime of SCADA systems can have severe economic, safety and security ramifications. One way to ensure vital asset protection is to adopt a viewpoint similar to an attacker to determine weaknesses and loopholes in defences. Such mind sets help to identify and fix potential breaches before their exploitation. This paper surveys tools and techniques to uncover SCADA system vulnerabilities. A comprehensive review of the selected approaches is provided along with their applicability.

Relay-Assisted Rateless Layered Multiple Description Video Delivery

Multiple description coding (MDC) has been proposed as a possible solution to real-time video delivery over relay-assisted wireless networks to exploit path diversity. In this paper, we study layered multiple description video over relay-assisted mobile networks, such as LTE-A, and develop a framework that routes packets to different relays based on source-channel-relay parameters. The proposed system comprises, besides layered MDC, (i) application-layer forward error correction via Random linear codes (RLC) that are very suitable in the relaying scenarios, due to their rateless nature, (ii) unequal error protection (UEP), using the recently proposed expanding window technique, that relies on probabilistic scheduling of layered packets. We generate layered multiple descriptions using data slicing and data partitioning features of H.264/AVC and conduct simulations by modelling a two-relay LTE-A setup with the finite state Markov chain model. Simulation results show benefits of relaying with optimized routing and UEP.

Unequal error protection for data partitioned H.264/AVC video streaming with raptor and random linear codes for DVB-H networks

Application layer forward error correction is becoming a popular addition to protocols for real-time video delivery over IP-based wireless networks. Since each part of video data is not equally important for video reconstruction, it is beneficial to divide video data based on its importance. Such partitioned data could then be provided with different degree of protection, with the important data having more protection against channel erasures. Data partitioning (DP) is one such low-cost feature in H.264/AVC enabling partitioning of video data based on its importance. In this paper, we propose an Unequal error protection (UEP) scheme to protect the DP H.264/AVC coded video data with Raptor and Random linear codes (RLC). The simulations have been performed using error traces which depict physical-layer Transport Stream (TS) packet losses in DVBH. The results highlight that for broadcasting applications with varying channel conditions, better results can be obtained with dynamic probability of selection of different importance layers.

WiseEye: Next Generation Expandable and Programmable Camera Trap Platform for Wildlife Research

The widespread availability of relatively cheap, reliable and easy to use digital camera traps has led to their extensive use for wildlife research, monitoring and public outreach. Users of these units are, however, often frustrated by the limited options for controlling camera functions, the generation of large numbers of images, and the lack of flexibility to suit different research environments and questions. We describe the development of a user-customisable open source camera trap platform named ‘WiseEye’, designed to provide flexible camera trap technology for wildlife researchers. The novel platform is based on a Raspberry Pi single-board computer and compatible peripherals that allow the user to control its functions and performance. We introduce the concept of confirmatory sensing, in which the Passive Infrared triggering is confirmed through other modalities (i.e. radar, pixel change) to reduce the occurrence of false positives images. This concept, together with user-definable metadata, aided identification of spurious images and greatly reduced post-collection processing time. When tested against a commercial camera trap, WiseEye was found to reduce the incidence of false positive images and false negatives across a range of test conditions. WiseEye represents a step-change in camera trap functionality, greatly increasing the value of this technology for wildlife research and conservation management.

Application layer systematic network coding for sliced H.264/AVC video streaming

Application Layer Forward Error Correction (AL-FEC) with rateless codes can be applied to protect the video data over lossy channels. Expanding Window Random Linear Codes (EW RLCs) are a flexible unequal error protection fountain coding scheme which can provide prioritized data transmission. In this paper, we propose a system that exploits systematic EW RLC for H.264/Advanced Video Coding (AVC) slice-partitioned data. The system prioritizes slices based on their PSNR contribution to reconstruction as well as temporal significance. Simulation results demonstrate usefulness of using relative slice priority with systematic codes for multimedia broadcast applications. References

Scalable broadcasting of sliced H.264/AVC over DVB-H network

Video broadcasting to heterogeneous receivers with varying channel conditions poses many challenges. The nature of the real-time data usually precludes any retransmission option. Forward error correction (FEC) can be used to protect the video data at the cost of adding some redundancy. The gains are increased further by partitioning the video data according to its importance for video reconstruction and adding the redundancy in proportion to the importance. Application Layer Forward Error Correction (AL-FEC) can be applied using rateless codes, which can potentially generate an unlimited number of packets on the fly from the source packets. Expanding Window Random Linear Codes (EW RLC) are a simple unequal error protection fountain coding scheme which can adapt to the prioritized data transmission. In this study we propose EW RLC for DVB-H broadcasting using H.264/Advanced video coding (AVC) slice partitioned data. The results show that EW RLC can be used to protect the slice-partitioned video data for multimedia broadcast applications to suit different data rates and channel conditions.

Adaptive layered multiple description coding for wireless video with expanding window Random linear codes

The error free communication of video data over multi-hop wireless networks is a challenging research problem. Multiple description coding has been proposed as a possible solution to leverage path diversity for error robustness. Forward error correction is an additional protection that can be provided to each description. Random linear codes have had renewed interest fostered by the multi-hop and multi-interface radio receivers. In this study, the descriptions are created using the encoding features of slicing and data partitioning for H.264/AVC video. The unequally protected video is protected with Expanding window-Random linear codes against channel errors. Fading channel error model is used to simulate real-world wireless channels. We also propose an adaptive scheme for video transmission over multiple paths. Such scheme may adapt to the varying channel conditions as is frequently the case in wireless transmission. The results show that the proposed scheme can be used for emerging wireless standards.