Alexander Rassau

Performance evaluation of IEEE 802.15.4 for mobile sensor networks

The IEEE 802.15.4 standard medium access control (MAC) protocol for low rate wireless personal area networks (LRWPAN) is design mainly for static sensor networks and its capability to support mobile sensor networks has not yet been established. To the best knowledge of authors, this is the first paper that evaluates the suitability of IEEE 802.15.4 MAC in mobile sensor networks environment. We evaluate the performance based on nodes speed and beacon order, and observe the effect on energy usage, packet delivery ratio and time required to associate with its coordinator. From the experiment we observe that the moving nodes experienced serious problems in association and synchronization and show results on energy usage, throughput , association and reassociation rate with different speeds of moving node. We also identify some key research problems that need to be addressed for successful implementations of IEEE 802.15..4 in mobile sensor networks environment.

A Segregation Based MAC Protocol for Real-Time Multimedia Traffic in WLANs

Providing quality of service (QoS) for multimedia applications in wireless local area networks (WLAN) is a very challenging task. This is mainly due to the real-time nature of multimedia traffic such as voice and video applications, that are sensitive to delay and jitter. QoS guarantees for real-time traffic must be imposed in WLAN so as to enable WLAN users to fully benefit from multimedia applications. The current medium access control (MAC) protocol that is widely used is the legacy IEEE 802.11, but this protocol does not support QoS for realtime traffic. To enhance the legacy 802.11, the IEEE 802.11e protocol was introduced to support QoS through prioritization of traffic. The 802.11e introduces a new co-ordination function known as hybrid coordination function (HCF). In this paper we study the performance of multimedia traffic in the legacy 802.11 and 802.11e and propose a technique to improve realtime traffic in multimedia applications by traffic segregation. We show that segregation of multimedia traffic improves delay and jitter performance of real-time traffic.

A Review of Current Neuromorphic Approaches for Vision, Auditory, and Olfactory Sensors

Conventional vision, auditory, and olfactory sensors generate large volumes of redundant data and as a result tend to consume excessive power. To address these shortcomings, neuromorphic sensors have been developed. These sensors mimic the neuro-biological architecture of sensory organs using aVLSI (analog Very Large Scale Integration) and generate asynchronous spiking output that represents sensing information in ways that are similar to neural signals. This allows for much lower power consumption due to an ability to extract useful sensory information from sparse captured data. The foundation for research in neuromorphic sensors was laid more than two decades ago, but recent developments in understanding of biological sensing and advanced electronics, have stimulated research on sophisticated neuromorphic sensors that provide numerous advantages over conventional sensors. In this paper, we review the current state-of-the-art in neuromorphic implementation of vision, auditory, and olfactory sensors and identify key contributions across these fields. Bringing together these key contributions we suggest a future research direction for further development of the neuromorphic sensing field.

QRP02-6: Efficient p-Cycles Design By Heuristic p-Cycle Selection and Refinement for Survivable WDM Mesh Networks

Using p-Cycles to protect against single span failures in Wavelength-Division Multiplexing (WDM) networks has been widely studied. p-Cycle retains not only the speed of ring-like restoration, but also achieves the capacity efficiency over mesh networks. However, in selecting an optimal set of p-cycles to achieve the minimum spare capacity and fast computational time is an NP-hard problem. To address this issue, we propose a heuristic approach to iteratively select and refine a set of p-cycles, which contains two algorithms: the Heuristic p-Cycle Selection (HPS) algorithm, and the Refine Selected Cycles (RSC) algorithm. Our simulation results show that the proposed approach is within 3.5% redundancy difference from the optimal solution with very fast computation time even for large networks.

The use of alignment cells in MMCC barcode

The QR code, a monochrome 2D barcode, is a popular and commonly used barcode system worldwide. QR codes can easily be read using a mobile phone with the appropriate decoder. As there is an increasing need for higher data capacity barcodes, some newer 2D barcodes, such as the MMCC code, have adopted the use of colour. However, the use of colour introduces more challenges for mobile phone decoders than with monochrome codes. In this paper, the use of alignment cells within the MMCC code is proposed to improve the robustness of the colour barcode when used in a mobile environment. With the addition of the alignment cells, the MMCC code is shown to achieve high data capacity even with a smaller physical size and the limitations of mobile phone cameras.

Monocycle Pulse Generator for an Inter/Intra-chip UWB Wireless Interconnect Communication System

This paper presents a novel ultra-wideband (UWB) wireless interconnect communication system using step recovery diodes (SRD) for an inter/intra-chip wireless interconnect communication system. A new UWB monocycle pulse generator has been simulated using HSPICE. This pulse generator is consisting of the step recovery diode, a Schottky diode and extra digital components. The proposed UWB pulse generator has been simulated by HSPICE for 0.18 um CMOS process and the simulation shows a train of sharp triangular pulse with a peak voltage of about 1.6 V under the supply voltage of 1.8 V. The designed UWB pulse generator generate a low power monocycle pulse and the circuit may be used as a part of an inter/intra chip UWB wireless interconnect communications system which transmit and receive a monocycle pulse signal at less than 1 cm distance.

Adaptive Segregation-Based MAC Protocol for Real-Time Multimedia Traffic in WLANs

Wireless local area networks (WLANs) have become very popular both in private and public sectors. Despite the fast expansion of WLANs in various environments, quality of service (QoS) issues for multimedia applications in WLANs are not yet resolved. Multimedia applications contain traffic that are sensitive to delay and jitter and therefore a best-effort protocol such as the legacy IEEE 802.11 is not suitable. The 802.11e protocol provides prioritization and classification of traffic to offer better QoS for real-time services. However, it leaves the design and implementation of many important optimization features to vendors. In this paper we introduce a mechanism to improve the delay and jitter of real-time traffic in WLAN nodes supporting multimedia applications. In our proposed mechanism, we segregate voice and video traffic from the best-effort traffic. We create a scheduler that schedules the access of real-time traffic and non real-time traffic to the medium with centralized polling and distributed contention respectively. We show that our proposed protocol performs better in terms of delay and jitter than the legacy 802.11 and 802.11e in a scenario where all wireless nodes carry multimedia traffic simultaneously.

A robust mobile business card reader using MMCC barcode

Business cards have existed since the 19th century and exchanging of business cards is common during introduction. The digital version, an electronic business card, helps to share information quickly and accurately. Also, it allows information to be stored and easily located. However, the current state of the art in business card readers using OCR technology usually fail in correctly reading all elements of the business card. Hence, in this paper, we proposed the use of an Mobile Multi-Colour Composite (MMCC) barcode printed on the business card. Containing the electronic version of the business card, the MMCC barcode allows cheap and accurate reading of the business card with a mobile phone camera. To highlight the effectiveness of the proposed method, we compared the results against commercially available business card readers, both in desktop and mobile versions.

An approach to Generate An Efficient set of Candidate p-Cycles in WDM Mesh Networks

In this paper we propose a new framework for computing an efficient set of p-cycles which can lead to superior performance in terms of capacity utilization in network protection. We first propose an algorithm for finding all fundamental cycles. Then, the set of candidate p-cycles is constructed by merging fundamental cycles. The number of proposed candidate p-cycles is small but they can construct more straddling link and have high a priori efficiency. Finally, an ILP model is employed to select an adequate set of p-cycles to ensure 100% protection while minimizing the total spare capacity. Our numerical results show that the number of candidate p-cycles generated is less than 7% out of all possible cycles for the test networks and the solutions are close to optimal

3D-softchip: a novel architecture for next-generation adaptive computing systems

This paper introduces a novel architecture for next-generation adaptive computing systems, which we term 3D-SoftChip. The 3D-SoftChip is a 3-dimensional (3D) vertically integrated adaptive computing system combining state-of-the-art processing and 3D interconnection technology. It comprises the vertical integration of two chips (a configurable array processor and an intelligent configurable switch) through an indium bump interconnection array (IBIA). The configurable array processor (CAP) is an array of heterogeneous processing elements (PEs), while the intelligent configurable switch (ICS) comprises a switch block, 32-bit dedicated RISC processor for control, on-chip program/data memory, data frame buffer, along with a direct memory access (DMA) controller. This paper introduces the novel 3D-SoftChip architecture for real-time communication and multimedia signal processing as a next-generation computing system. The paper further describes the advanced HW/SW codesign and verification methodology, including high-level system modeling of the 3D-SoftChip using SystemC, being used to determine the optimum hardware specification in the early design stage.