Engineering Commons^™

Wireless Positioning Techniques: A Developer's Update, Seamus Rooney, Keith Gardiner, James Carswell

Conference papers

This paper describes the current efforts to develop an open source, privacy sensitive, location determination software component for mobile devices. Currently in mobile computing, the ability of a mobile device to determine its own location is becoming increasingly desirable as the usefulness of such a feature enhances many commercial applications. There have been numerous attempts to achieve this from both the network positioning perspective and also from the wireless beacon angle not to mention the integration of GPS into mobile devices. There are two important aspects to consider when using such a system which are privacy and cost. This paper …

0.5w High Linearity Power Amplifier For Broadband Wireless (3.3 ~ 3.9 Ghz), Chin-Leong Lim

Chin-Leong Lim

This paper presents a 0.5 Watt amplifier that operates over the 3.3 ~ 3.9 GHz range. The target applications are pre-driver in base-stations and power amplifier in subscriber units. The design marries good Third Order Output Intercept Point (OIP3) and exceptional Power Added Efficiency (PAE) at IdB gain compression point (PldB). The performances are: -G = 11.8 dB, IRL & ORL < -8 dB, PldB = 28.5 dBm and OIP3 = 42.6 dBm. The superior performance is achieved through the use of Avago Technologies' proprietary 0.25um GaAs Enhancement mode pHEMT process. The device requires simple matching components to achieve wide bandwidth because of the built-in input pre-match. From the reliability standpoint, pHEMT devices are eminently suited to PA use -the drain to source resistance (RDSon) will inherently rise to counteract the thermal runaway that blights bipolar and HBT PAs. The internal bias circuit is temperature compensated and can be adjusted for either class A or class AB operation. The device is housed inside a standard 16 pin LPCC 3X3 package.

The Effects Of Contention Among Stations On Video Streaming Applications Over Wireless Local Area Networks: An Experimental Approach, Nicola Cranley, Tanmoy Debnath

Conference papers

Multimedia streaming applications have a large impact on the resource requirements of the WLAN. There are many variables involved in video streaming, such as the video content being streamed, how the video is encoded and how it is sent. This makes the role of radio resource management and the provision of QoS guarantees extremely difficult. For video streaming applications, packet loss and packets dropped due to excessive delay are the primary factors that affect the received video quality. In this paper, we experimentally analyse the effects of contention on the performance of video streaming applications with a given delay constraint …

Examination Of Energy And Group Velocities In Positive And Negative Index Chiral Materials With And Without Dispersion, Monish Ranjan Chatterjee, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

Concepts of energy and group velocities, Poynting and propagation vectors are examined for both positive and negative index materials. Known definitions for these entities are explored in terms of the interplay of chirality and dispersion.

Energy-Efficient Querying Of Wireless Sensor Networks, Christopher R. Mann

Theses and Dissertations

Due to the distributed nature of information collection in wireless sensor networks and the inherent limitations of the component devices, the ability to store, locate, and retrieve data and services with minimum energy expenditure is a critical network function. Additionally, effective search protocols must scale efficiently and consume a minimum of network energy and memory reserves. A novel search protocol, the Trajectory-based Selective Broadcast Query protocol, is proposed. An analytical model of the protocol is derived, and an optimization model is formulated. Based on the results of analysis and simulation, the protocol is shown to reduce the expected total network …

Experimental Tuning Of The Aifsn Parameter To Prioritize Voice Over Data Transmission In 802.11e Wlan Networks, Miroslaw Narbutt, Mark Davis

Conference papers

In this paper we experimentally study the impact of one EDCA parameter, namely AIFSN on a mixed voice/data wireless transmission. In particular we investigate how the tuning of this parameter affects both the voice transmission quality and background data throughput. We predict end-to-end voice transmission quality from time varying transmission impairements using the latest Appendix to the ITU-T E-model. Our experiemental results show that the tuning of the AIFSN parameter can successfully prioritize voice transmission over data in a real 802.11e network. To the best of our knowledge this is the first experimental investigation on tuning of MAC layer parameters …

Experimental Tuning Of Aifsn And Cwmin Parameters To Prioritize Voice Over Data Transmission In 802.11e Wlan Networks, Miroslaw Narbutt, Mark Davis

Conference papers

In this paper we experimentally study the impact of two EDCA parameters, namely AIFSN and CWmin, on a mixed voice/data wireless transmission. In particular we investigate how the tuning of these parameters affects both the voice transmission quality and background data throughput. We predict end-to-end voice transmission quality from time varying transmission impairments using the latest Appendix to the ITU-T E-model. Our experimental results show that the tuning of the EDCA parameters can be used to successfully prioritize voice transmission over data in real 802.11e networks. We also demonstrate that the AIFSN parameter more effectively protects voice calls against background …

An Experimental Investigation Of Parallel Multimedia Streams Over Ieee 802.11e Wlan Networks Using Txop, Nicola Cranley, Tanmoy Debnath, Mark Davis

Conference papers

In this paper we perform an experimental investigation of the IEEE 802.11 TXOP facility to enhance the transmission of parallel multimedia streaming sessions through efficient bandwidth reservation and explicitly consider both the audio and video streams. The delay constraints associated with the audio and video streams that comprise a multimedia session pose the greatest challenge since real-time multimedia is particularly sensitive to delay as the packets require a strict bounded end-to-end delay. We show how the TXOPlimit parameter can be efficiently dimensioned to reduce the tranmission delay for the video frames. Due to tis frame-based nature, video applications are considered …

Analysis Of Beam Propagation In 90-Degree Holographic Recording And Readout Using Transfer Functions And Numerical 2-D-Laplace Inversion, Monish Ranjan Chatterjee, Partha P. Banerjee, George Nehmetallah

Electrical and Computer Engineering Faculty Publications

Recently, 2-D-Laplace analysis of recording and readout of edge-holograms was reported. Numerical Laplace inversion was examined for simple test cases. Inversion algorithms are applied to examine beam shaping and distortion in photovoltaic and photorefractive materials.

Evaluating Software Engineering Processes In Commercial And Community Open Source Projects, Tony Wasserman, Eugenio Capra

Tony Wasserman

We describe a current study for obtaining information about management of commercial and community open source projects. We have interviewed and surveyed leaders of more than 75 open source projects. Questions focused on the styles of leadership and communication, with a technical focus on testing and quality assurance processes. This paper describes the methods used to identify and contact subjects, as well as the questions posed and some results.

User Quality Of Experience-Aware Multimedia Streaming Over Wireless Home Area Network, Gabriel-Miro Muntean, Nicola Cranley

Conference papers

For multimedia streaming over wireless networks, there is a trade-off between the capacity of the wireless links and the end-user perceived-quality, which can be affected by the compression scheme used, content characteristics and adaptation algorithm (if any). In this paper, this trade-off is investigated for streaming various motion content multimedia over an IEEE 802.11b-based Wireless-Home Area Network using the Quality-Oriented Adaptation Scheme (QOAS). QOAS performance is compared to that of a non-adaptive scheme when using MPEG-2 and MPEG-4 encoding in terms of average end-user perceived quality, number of streaming sessions concurrently supported, loss rate, delay, jitter and total throughput. Simulation …

Diseño De Una Terminal Interactiva Para Información A Clientes De Un Centro Comercial Y Desarrollo Del Sistema De Información, Diego Enrique Parra Montañez, Ronald Yesid Ramírez Gracia

Ingeniería en Automatización

No abstract provided.

Tackle Wideband Rf Switching With Pin Diodes, Chin-Leong Lim

Chin-Leong Lim

PIN diodes make cheaper, faster and more reliable RF switches than the mechanical competition. The two methods of constructing PIN diodes, bulk and epitaxial, result in significantly different bias current, linearity and lower frequency limit. This paper compares the wideband series switching performances of a bulk PIN diode (w = 22.5 um, Tau = 300 ns) and an epitaxial diode (w = 6.5 um, Tau = 180 ns) in similar low-cost, miniature SOD-323 packages. Through simulation and experiment, we detected significant differences in insertion loss, isolation, and third-order intercept (IP3) performances between the two diode types. In conclusion, the design …

Improvement To The Data Logging Capability Of A Cough Monitoring System, Matthew Barlow

Inquiry: The University of Arkansas Undergraduate Research Journal

Data logging capability of a previously developed self contained cough recorder using an accelerometer as the sensing element is improved by using a secure digital memory card for later retrieval on a computer. Firmware is developed to enhance the functionality of the cough recorder. Existing libraries are modified for increased write rates. Increased writing speed allows 8-bit sampling at rates exceeding 8kHz, allowing for detailed time and frequency domain analysis. Additional features have also been developed to enable easy management of recordings, such as a file system compatibility with Microsoft Windows., and unique file names for each recording.

Supporting Real-Time Cognitive State Classification On A Mobile Individual, Michael C. Dorneich, Stephen D. Whitlow, Santosh Mathan, Patricia May Ververs, Deniz Erdogmus, Andre Adami, Misha Pavel, Tian Lan

Michael C. Dorneich

The effectiveness of neurophysiologically triggered adaptive systems hinges on reliable and effective signal processing and cognitive state classification. Although this presents a difficult technical challenge in any context, these concerns are particularly pronounced in a system designed for mobile contexts. This paper describes a neurophysiologically derived cognitive state classification approach designed for ambulatory task contexts. We highlight signal processing and classification components that render the electroencephalogram (EEG) -based cognitive state estimation system robust to noise. Field assessments show classification performance that exceeds 70% for all participants in a context that many have regarded as intractable for cognitive state classification using …

Atmospheric Turbulence Compensation Of Point Source Images Using Asynchronous Stochastic Parallel Gradient Descent Technique On Amos 3.6 M Telescope, Mikhail Vorontsov, Jim F. Riker, Gary W. Carhart, Venkata S. Rao Gudimetla, Leonid A. Beresnev, Thomas Weyrauch

Electrical and Computer Engineering Faculty Publications

The Stochastic Parallel Gradient Descent Technique-based Adaptive Optics (SPGD-AO) system described in this presentation does not use a conventional wavefront sensor. It uses a metric signal collected by a single pixel detector placed behind a pinhole in the image plane to drive three deformable mirrors (DMs). The system is designed to compensate the image for turbulence effects. The theory behind this method is described in detail in [1]. However this technique, while widely simulated and tested in the laboratory, was not yet verified in astronomical field site experiments. During the month of May 2007, a series of experiments with SPGD-AO …

Adaptive Optics Performance Over Long Horizontal Paths: Aperture Effects In Multi-Conjugate Adaptive Optical Systems, Miao Yu, Mikhail Vorontsov, Svetlana Lachinova, Jim F. Riker, Venkata S. Rao Gudimetla

Electrical and Computer Engineering Faculty Publications

We analyze various scenarios of the aperture effects in adaptive optical receiver-type systems when inhomogeneities of the wave propagation medium are distributed over long horizontal propagation path, or localized in a few thin layers remotely located from the receiver telescope pupil. Phase aberration compensation is performed using closed-loop control architectures based on phase conjugation and decoupled stochastic parallel gradient descent (DSPGD) control algorithms. Both receiver system aperture diffraction effects and the impact of wave-front corrector position on phase aberration compensation efficiency are analyzed for adaptive systems with single or multiple wave-front correctors.

A Service Provisioning Platform For Beyond 3g - The Telecommunication Service Exchange, Donna Griffin

Theses

From the inception of mobile communications one of the most important factors contributing to its success has been a good understanding of user requirements. In the first generation, mobile networks offered subscribers the freedom to communicate regardless of their locations and the joy of instant access to voice telephony services. This provided a competitive edge over wire line communication networks and resulted in large revenue streams. However over the past decade, mobile network operators have been faced with a number of factors that have incurred significant costs and resulting reduced revenue. These factors include deregulation, increased competition and technological progress …

Krylov Subspaces From Bilinear Representations Of Nonlinear Systems, Marissa Condon, Rossen Ivanov

Articles

For efficient simulation of state-of-the-art dynamical systems as arise in all aspects of engineering, the development of reduced-order models is of paramount importance. While linear reduction techniques have received considerable study, increasingly nonlinear model reduction is becoming a significant field of interest. From a circuits and systems viewpoint, systems involving micromachined devices or systems involving mixed technologies necessitate the development of reduced-order nonlinear models. From a control systems viewpoint, the design of controllers for nonlinear systems is greatly facilitated by nonlinear model reduction strategies. To this end, the paper proposes two novel model-reduction strategies for nonlinear systems. The first involves …

Study Of Soliton Stabilization In D+1 Dimensions Using Novel Analytical And Numerical Techniques, George Nehmetallah, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

In this Chapter, we provide a brief review of the underlying nonlinear Schrödinger and associated equations that model spatio-temporal propagation in one and higher dimensions in a nonlinear dispersive environment. Particular attention is given to fast adaptive numerical techniques to solve such equations, and in the presence of dispersion and nonlinearity management, saturating nonlinearity and nonparaxiality. A unique variational approach is also outlined which helps in determining the ranges of nonlinearity and dispersion parameters to ensure stable solutions of the nonlinear equations. The propagation of 3+1 dimensional spatio-temporal pulses, or optical bullets is also modeled using a fast adaptive split-step …

Using Flossmole Data In Determining Business Readiness Ratings, Tony Wasserman, Ashutosh Das

Tony Wasserman

This paper is a preliminary report on using FLOSSmole data retrieved from open source repositories (forges) to calculate Business Readiness Rating scores.

Methods And Tools For Developing Interactive Information Systems: An Historical Perspective, Tony Wasserman

Tony Wasserman

This paper describes the evolution of hardware and software technology over the past three decades, focusing on approaches for building interactive information systems and web applications. Successive generations of technology have used advances in hardware and software technology, along with increasingly sophisticated development methods and tools, to reduce development times and to produce a better user experience. After describing the key technology characteristics of each generation, this paper also describes the evolution of a specific methodology, User Software Engineering, from its origins in the 1970’s to its applicability to the development of modern applications.

On-Chip Implementation Of High Speed And High Resolution Pipeline Radix 2 Fft Algorithm, Rozita Teymourzadeh, Masuri Othman

Dr. Rozita Teymourzadeh, CEng.

Vlsi Implementation Of High Speed And High Resolution Fft Algorithm Based On Radix 2 For Dsp Application, Nooshin Mahdavi, Rozita Teymourzadeh, Masuri Othman

Dr. Rozita Teymourzadeh, CEng.

A Busy-Tone Based Mac Scheme For Wireless Ad Hoc Networks Using Directional Antennas, Hong-Ning Dai, Kam-Wing Ng, Min-You Wu

Hong-Ning Dai

Applying directional antennas in wireless ad hoc networks offers numerous benefits, such as extended communication range, increased spatial reuse, improved capacity and suppressed interference. However, directional antennas can cause new location-dependent carrier sensing problems, such as new hidden terminal and deafness problems, which can cause severe penalties to the performance. Recently, a few schemes have been proposed to tackle these problems. However, these methods can provide limited solutions on the hidden terminal and deafness problems. We propose a new MAC protocol, termed the busy-tone based directional medium access control (BT-DMAC) protocol. When the transmission is in progress, the sender and …