Open Access. Powered by Scholars. Published by Universities.®

Systems and Communications Commons

Open Access. Powered by Scholars. Published by Universities.®

2,317 Full-Text Articles 3,340 Authors 1,148,077 Downloads 102 Institutions

All Articles in Systems and Communications

Faceted Search

2,317 full-text articles. Page 100 of 101.

Scalable And Fault Tolerant Group Key Management, Nicholas A. Lupien 2010 Air Force Institute of Technology

Scalable And Fault Tolerant Group Key Management, Nicholas A. Lupien

Theses and Dissertations

To address the group key management problem for modern networks this research proposes a lightweight group key management protocol with a gossip-based dissemination routine. Experiments show that by slightly increasing workload for the key update mechanism, this protocol is superior to currently available tree-based protocols with respect to reliability and fault tolerance, while remaining scalable to large groups. Java simulations show that the protocol efficiently distributes keys to large groups in the midst of up to 35 percent node failure rates. In addition, it eliminates the need for logical key hierarchy while preserving an overall reduction in rekey messages to ...


Static And Dynamic Component Obfuscation On Reconfigurable Devices, Camdon R. Cady 2010 Air Force Institute of Technology

Static And Dynamic Component Obfuscation On Reconfigurable Devices, Camdon R. Cady

Theses and Dissertations

Computing systems are used in virtually every aspect of our lives. Technology such as smart phones and electronically controlled subsystems in cars is becoming so commonly used that it is virtually ubiquitous. Sometimes, this technology can be exploited to perform functions that it was never intended to perform, or fail to provide information that it is supposed to protect. X-HIA was shown to be effective at identifying several circuit components in a significantly shorter time than previous identification methods. Instead of requiring a number of input/output pairings that grows factorially or exponentially as the circuit size grows, it requires ...


Improved Multispectral Skin Detection And Its Application To Search Space Reduction For Dismount Detection Based On Histograms Of Oriented Gradients, Adam L. Brooks 2010 Air Force Institute of Technology

Improved Multispectral Skin Detection And Its Application To Search Space Reduction For Dismount Detection Based On Histograms Of Oriented Gradients, Adam L. Brooks

Theses and Dissertations

Due to the general shift from conventional warfare to terrorism and urban warfare by enemies of the United States in the late 20th Century, locating and tracking individuals of interest have become critically important. Dismount detection and tracking are vital to provide security and intelligence in both combat and homeland defense scenarios including base defense, combat search and rescue (CSAR), and border patrol. This thesis focuses on exploiting recent advances in skin detection research to reliably detect dismounts in a scene. To this end, a signal-plus-noise model is developed to map modeled skin spectra to the imaging response of an ...


Maximum Damage Malware Attack In Mobile Wireless Networks, MHR Khouzani, Saswati Sarkar, Eitan Altman 2010 University of Pennsylvania

Maximum Damage Malware Attack In Mobile Wireless Networks, Mhr Khouzani, Saswati Sarkar, Eitan Altman

Departmental Papers (ESE)

Malware attacks constitute a serious security risk that threatens to slow down the large scale proliferation of wireless applications. As a first step towards thwarting this security threat, we seek to quantify the maximum damage inflicted on the system owing to such outbreaks and identify the most vicious attacks. We represent the propagation of malware in a battery-constrained mobile wireless network by an epidemic model in which the worm can dynamically control the rate at which it kills the infected node and also the transmission range and/or the media scanning rate. At each moment of time, the worm at ...


Xins, Kyle Howen 2010 California Polytechnic State University - San Luis Obispo

Xins, Kyle Howen

Electrical Engineering

The XINS seeks to provide a navigation system that is sufficient for remote control or automation of a small UAV. This will be accomplished with a general knowledge in electrical engineering concepts and with equipment available to hobbyists.

This paper covers the theory of design and the first steps to prototyping an aircraft navigation system. Though no testing on actual aircraft was available, simulations and ground tests (in an automobile) were performed. All testing supported the intended function of the XINS.

Given some size and power supply modification, the presented XINS prototype should be able to provide all required data ...


Reverberation-Chamber Test Environment For Outdoor Urban Wireless Propagation Studies, Helge Fielitz, Kate A. Remley, Christopher L. Holloway, Qian Zhang, Qiong Wu, David W. Matolak 2010 University of South Carolina - Columbia

Reverberation-Chamber Test Environment For Outdoor Urban Wireless Propagation Studies, Helge Fielitz, Kate A. Remley, Christopher L. Holloway, Qian Zhang, Qiong Wu, David W. Matolak

Faculty Publications

We introduce a test environment to replicate the well-known clustering of reflections in power delay profiles arising from late-time delays and reflections. Urban wireless propagation environments are known to exhibit such clustering. The test setup combines discrete reflections generated by a fading simulator with the continuous distribution of reflections created in a reverberation chamber. We describe measurements made in an urban environment in Denver, CO, that illustrate these multiple distributions of reflections. Our comparison of measurements made in the urban environment to those made in the new test environment shows good agreement.


A Graduate Education In Software Management And The Software Business For Mid-Career Professionals, Ray Bareiss, Gladys Mercier 2010 Carnegie Mellon University

A Graduate Education In Software Management And The Software Business For Mid-Career Professionals, Ray Bareiss, Gladys Mercier

Ray Bareiss

Given the unique nature of the software business, the faculty of Carnegie Mellon University’s Silicon Valley campus concluded that mid-career software professionals would be better served by a tailored master’s degree focusing on software management and more broadly on the business of software than by a typical MBA. Our software management master’s program integrates business, technical, and soft skills to prepare our students for technical leadership in their current companies or in entrepreneurial ventures. Our initial program built on the strengths of Carnegie Mellon’s world-class software engineering education. We targeted students working in large companies, engaged ...


Coaching Via Cognitive Apprenticeship, Ray Bareiss, Martin Radley 2010 Carnegie Mellon University

Coaching Via Cognitive Apprenticeship, Ray Bareiss, Martin Radley

Ray Bareiss

At Carnegie Mellon’s Silicon Valley campus we employ a learn by- doing educational approach in which nearly all student learning, and thus instruction, is in the context of realistic, team based projects. Consequently, we have adopted coaching as our predominant teaching model. In this paper we reflect on our experience with the nature of teaching by coaching using a framework derived from Cognitive Apprenticeship, and explain how we employ the techniques it suggests in our teaching. We also discuss a range of instructional tensions that arise in teaching by coaching and present a survey of student attitudes regarding the ...


Miniature Ceramic Pifa For Uwb Band Group 3 And 6, David Kearney, Matthias John, Max Ammann 2010 Technological University Dublin

Miniature Ceramic Pifa For Uwb Band Group 3 And 6, David Kearney, Matthias John, Max Ammann

Articles

A ceramic chip planar inverted-F antenna (PIFA) is proposed for integration into a mobile handset providing UWB functionality across band groups 3 and 6. The antenna design exhibits a total efficiency of greater than 50% across the entire 6.39 GHz bandwidth while maintaining a very small volume of 57.6 mm^3 . The antenna uses a combination of the normal PIFA resonance and a second resonance due to the ceramic block to achieve a broad ultrawideband (UWB) bandwidth.


Finite Tree-Based Decoding Of Low-Density Parity-Check Codes, Eric T. Psota 2010 University of Nebraska-Lincoln

Finite Tree-Based Decoding Of Low-Density Parity-Check Codes, Eric T. Psota

Theses, Dissertations, and Student Research from Electrical & Computer Engineering

Low-density parity-check codes are commonly decoded using iterative message-passing decoders, such as the min-sum and sum-product decoders. Computer simulations demonstrate that these suboptimal decoders are capable of achieving low probability of bit error at signal-to-noise ratios close to capacity. However, current methods for analyzing the behavior of the min-sum and sum-product decoders fails to produce usable bounds on the probability of bit error. Thus, the resulting probability of bit error when using these decoders remains largely unknown for signal-to-noise ratios beyond the reach of simulation. For this reason, it is worth considering alternative methods for decoding low-density parity-check codes. New ...


Harvesting Single Ferroelectric Domain Stressed Nanoparticles For Optical And Ferroic Applications, Gary Cook, J. L. Barnes, S. A. Basun, Dean R. Evans, Ron F. Ziolo, Arturo Ponce, Victor Yu. Reshetnyak, Anatoliy Glushchenko, Partha P. Banerjee 2010 Air Force Research Laboratory

Harvesting Single Ferroelectric Domain Stressed Nanoparticles For Optical And Ferroic Applications, Gary Cook, J. L. Barnes, S. A. Basun, Dean R. Evans, Ron F. Ziolo, Arturo Ponce, Victor Yu. Reshetnyak, Anatoliy Glushchenko, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

We describe techniques to selectively harvest single ferroelectric domain nanoparticles of BaTiO3 as small as 9 nm from a plethora of nanoparticles produced by mechanical grinding. High resolution transmission electron microscopy imaging shows the unidomain atomic structure of the nanoparticles and reveals compressive and tensile surface strains which are attributed to the preservation of ferroelectric behavior in these particles.

We demonstrate the positive benefits of using harvested nanoparticles in disparate liquid crystal systems.


Characterization Of Atmospheric Turbulence Effects Over 149 Km Propagation Path Using Multi-Wavelength Laser Beacons, Mikhail Vorontsov, Gary W. Carhart, Venkata S. Rao Gudimetla, Thomas Weyrauch, Eric Stevenson, Svetlana Lachinova, Leonid A. Beresnev, Jony Jiang Liu, Karl Rehder, Jim F. Riker 2010 University of Dayton

Characterization Of Atmospheric Turbulence Effects Over 149 Km Propagation Path Using Multi-Wavelength Laser Beacons, Mikhail Vorontsov, Gary W. Carhart, Venkata S. Rao Gudimetla, Thomas Weyrauch, Eric Stevenson, Svetlana Lachinova, Leonid A. Beresnev, Jony Jiang Liu, Karl Rehder, Jim F. Riker

Electrical and Computer Engineering Faculty Publications

We describe preliminary results of a set of laser beam propagation experiments performed over a long (149 km) near-horizontal propagation path between Mauna Loa (Hawaii Island) and Haleakala (Island of Maui) mountains in February 2010. The distinctive feature of the experimental campaign referred to here as the Coherent Multi-Beam Atmospheric Transceiver (COMBAT) experiments is that the measurements of the atmospheric-turbulence induced laser beam intensity scintillations at the receiver telescope aperture were obtained simultaneously using three laser sources (laser beacons) with different wavelengths (λ1 = 0.53 μm, λ2 = 1.06 μm, and λ3 = 1.55 μm). The presented experimental results on ...


E-Fraud Prevention Based On The Self-Authentication Of E-Documents, Jonathan Blackledge, Eugene Coyle 2010 Technological University Dublin

E-Fraud Prevention Based On The Self-Authentication Of E-Documents, Jonathan Blackledge, Eugene Coyle

Conference papers

We consider a method for preventing e-Fraud in which a binary image is encrypted with a floating point cipher using a convolution operation and the output quantized into a 1-bit array generating a binary image ciphertext. The output is then ‘embedded’ in a host image to hide the encrypted information. Embedding is undertaken either in the lowest 1-bit layer or multiple 1-bit layers. Decryption is accomplished by: (i) extracting the binary image from the host image; (ii) correlating the result with the original cipher. In principle, any cipher generator can be used for this purpose and the method has been ...


The Changing Patterns Of Internet Usage, Christopher S. Yoo 2010 University of Pennsylvania Carey Law School

The Changing Patterns Of Internet Usage, Christopher S. Yoo

Faculty Scholarship at Penn Carey Law

The Internet unquestionably represents one of the most important technological developments in recent history. It has revolutionized the way people communicate with one another and obtain information and created an unimaginable variety of commercial and leisure activities. Interestingly, many members of the engineering community often observe that the current network is ill-suited to handle the demands that end users are placing on it. Indeed, engineering researchers often describe the network as ossified and impervious to significant architectural change. As a result, both the U.S. and the European Commission are sponsoring “clean slate” projects to study how the Internet might ...


Super-High-Frequency Two-Port Aln Contour-Mode Resonators For Rf Applications, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza 2010 University of Pennsylvania

Super-High-Frequency Two-Port Aln Contour-Mode Resonators For Rf Applications, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza

Departmental Papers (ESE)

This paper reports on the design and experimental verification of a new class of thin-film (250 nm) superhigh- frequency laterally-vibrating piezoelectric microelectromechanical (MEMS) resonators suitable for the fabrication of narrow-band MEMS filters operating at frequencies above 3 GHz. The device dimensions have been opportunely scaled both in the lateral and vertical dimensions to excite a contourextensional mode of vibration in nanofeatures of an ultra-thin (250 nm) AlN film. In this first demonstration, 2-port resonators vibrating up to 4.5 GHz have been fabricated on the same die and attained electromechanical coupling, kt^2, in excess of 1.5%. These devices ...


Real-Time On-Board Object Tracking For Cooperative Flight Control, Ajay Kumar Mandava, Emma Regentova, Henry Selvaraj 2010 University of Nevada, Las Vegas

Real-Time On-Board Object Tracking For Cooperative Flight Control, Ajay Kumar Mandava, Emma Regentova, Henry Selvaraj

Electrical and Computer Engineering Faculty Publications

One of possible cooperative Situations for flights could be a scenario when the decision on a new path is taken by A Certain fleet member, who is called the leader. The update on the new path is Transmitted to the fleet members via communication That can be noisy. An optical sensor can be used as a back-up for re-estimating the path parameters based on visual information. For A Certain topology, the issue can be solved by continuous tracking of the leader of the fleet in the video sequence and re-adjusting parameters of the flight, accordingly. To solve such a problem ...


The Effect Of Curvature Rate On The Received Power In Parabolic Reflector, Amean Al_Safi 2009 Western Michigan University

The Effect Of Curvature Rate On The Received Power In Parabolic Reflector, Amean Al_Safi

Amean S Al_Safi

In this paper we study the effect of curvature rate on the generated electric field at the focus point if the frequency and diameter are constants .We assume that the incident electromagnetic waves distributed uniformly on each point of the reflector surface ;hence we can imagine that this reflector has uniform surface charge ,and this body will generate an electric field on all points in front of it (including the focus point) . This field can be obtained by using coulomb’s law .The derived expression for electric field show that X and Y components will vanish and the electric field ...


Embedded Systems As Datacenters, Robert Iannucci 2009 RAI Laboratory LLC

Embedded Systems As Datacenters, Robert Iannucci

Robert A Iannucci

No abstract provided.


Super-High-Frequency Two-Port Aln Contour-Mode Resonators For Rf Applications, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza 2009 University of Pennsylvania

Super-High-Frequency Two-Port Aln Contour-Mode Resonators For Rf Applications, Matteo Rinaldi, Chiara Zuniga, Chengjie Zuo, Gianluca Piazza

Matteo Rinaldi

This paper reports on the design and experimental verification of a new class of thin-film (250 nm) super-high-frequency laterally-vibrating piezoelectric microelectromechanical (MEMS) resonators suitable for the fabrication of narrow-band MEMS filters operating at frequencies above 3 GHz. The device dimensions have been opportunely scaled both in the lateral and vertical dimensions to excite a contour-extensional mode of vibration in nanofeatures of an ultra-thin (250 nm) AlN film. In this first demonstration, 2-port resonators vibrating up to 4.5 GHz have been fabricated on the same die and attained electromechanical coupling, kt2, in excess of 1.5%. These devices are employed ...


The Effect Of The Digit Slicing Architecture On The Fft Butterfly, Yazan Samir, Rozita Teymourzadeh 2009 Faculty of Engineering, Technology and Built Environment UCSI University

The Effect Of The Digit Slicing Architecture On The Fft Butterfly, Yazan Samir, Rozita Teymourzadeh

Dr. Rozita Teymourzadeh, CEng.

Most communications systems tend to achieve bandwidth, power and cost efficiencies to capable to describe modulation scheme. Hence for signal modulation orthogonal frequency division multiplexing (OFDM) transceiver is introduced to cover communications demand in four generation. However high performance Fast Fourier Transforms (FFT) as a main heart of OFDM acts beyond the view. In order to achieve capable FFT, design and realization of its efficient internal structure is key issues of this research work. In this paper implementation of high performance butterfly for FFT by applying digit slicing technique is presented. The proposed design focused on the trade-off between the ...


Digital Commons powered by bepress