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University of Nebraska - Lincoln

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Articles 931 - 960 of 1069

Full-Text Articles in Computer Engineering

Optimal Receiver For Space Time Spreading Across A Time Hopping Ppm Over Ultra Wideband Saleh-Valenzuela Mimo Channel, Peter Vial, Beata J. Wysocki, Tadeusz A. Wysocki Dec 2007

Optimal Receiver For Space Time Spreading Across A Time Hopping Ppm Over Ultra Wideband Saleh-Valenzuela Mimo Channel, Peter Vial, Beata J. Wysocki, Tadeusz A. Wysocki

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

This paper outlines a technique which can use multiple transmit antennas to send more than one binary bit using the same number of transmit antennas over a single transmission. It uses Ultra Wideband orthogonal pulse position modulation to achieve this, with the receiver employing a Rake receiver and a Maximum Ratio Combiner optimal detector. This is done over a Space Time Spreading Time Hopping Ultra Wideband Pulse Position Modulation system assuming a rich multipath Saleh-Valenzuela MIMO channel model. Simulation results indicate that a significant gain can be achieved compared with other proposed schemes utilising multiple transmit antennas for Ultra Wide …

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Application Of Intermediate Wavelength Band Spectroscopic Ellipsometry To In-Stu. Real Time Fabrication Of Multiple Layer Alternating Hghalow Refractive Index Filters, Blaine D. Johs, Jeffery S. Hale, John A. Woollam, Craig M. Herzinger Nov 2007

Application Of Intermediate Wavelength Band Spectroscopic Ellipsometry To In-Stu. Real Time Fabrication Of Multiple Layer Alternating Hghalow Refractive Index Filters, Blaine D. Johs, Jeffery S. Hale, John A. Woollam, Craig M. Herzinger

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed is application of oblique angle of incidence, reflection and/or transmission mode spectroscopic ellipsometry PSI and/or DELTA, (including combinations thereof and/or mathematical equivalents), vs. wavelength data over an intermediate wavelength band range around a pass or reject band, to monitor and/or control fabrication of multiple layer high/low refractive index band-pass, band-reject and varied attenuation vs. wavelength thin film interference filters, either alone or in combination with transmissive non-ellipsometric electromagnetic beam turning point vs. layer data obtained at an essentially normal angle of incidence.

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A Theoretical Framework For Quality-Aware Cross-Layer Optimized Wireless Multimedia Communications, Song Chi, Haohong Wang, Dalei Wu Nov 2007

A Theoretical Framework For Quality-Aware Cross-Layer Optimized Wireless Multimedia Communications, Song Chi, Haohong Wang, Dalei Wu

Department of Electrical and Computer Engineering: Faculty Publications

Although cross-layer has been thought as one of themost effective and efficient ways formultimedia communications over wireless networks and a plethora of research has been done in this area, there is still lacking of a rigorous mathematical model to gain indepth understanding of cross-layer design tradeoffs, spanning from application layer to physical layer. As a result, many existing cross-layer designs enhance the performance of certain layers at the price of either introducing side effects to the overall system performance or violating the syntax and semantics of the layered network architecture. Therefore, lacking of a rigorous theoretical study makes existing cross-layer …

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Use Of Ellipsometry And Surface Plasmon Resonance In Monitoring Thin Film Deposition Or Removal From A Substrate Surface, John A. Woollam, Blaine D. Johs, Thomas E. Tiwald, Martin M. Liphardt, James D. Welch Oct 2007

Use Of Ellipsometry And Surface Plasmon Resonance In Monitoring Thin Film Deposition Or Removal From A Substrate Surface, John A. Woollam, Blaine D. Johs, Thomas E. Tiwald, Martin M. Liphardt, James D. Welch

Department of Electrical and Computer Engineering: Faculty Publications

Improved methodology for monitoring deposition or removal of material to or from a process and/or Wittness substrate Which demonstrates a negative e1 at some Wave length. The method involves detection of changes in P-polarized electromagnetism ellipsometric DELTA at SPR Resonance Angle-of-lncidence (A01) to monitor deposition of and/or removal of minute amounts of materials onto, or from, said process and/or Witness substrate. The methodology can optionally monitor ellipsometric PS1, and involves simultaneously or sequentially applying non-P-polarized electromagnetism at the same angle of incidence, or electromagnetic radiation of any polarization at a different angle-of-incidence and Wavelength to the process or Witt ness …

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Flying Mobile On-Board Ellipsometer, Polarimeter, Reflectometer And The Like Systems, Blaine D. Johs,, Ping He, Martin M. Liphardt, Christopher A. Goeden, John A. Woollam, James D. Welch Oct 2007

Flying Mobile On-Board Ellipsometer, Polarimeter, Reflectometer And The Like Systems, Blaine D. Johs,, Ping He, Martin M. Liphardt, Christopher A. Goeden, John A. Woollam, James D. Welch

Department of Electrical and Computer Engineering: Faculty Publications

A substantially self-contained “on-boar ” material system investigation system functionally mounted on a three dimen sional locational system to enable positioning at desired locations on, and distances from, the surface of a large sample, including the capability to easily and conveniently change the angle-of-incidence of a beam of electromagnetic radiation onto a sample surface.

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Sample Entry Purge System In Spectrophotometer, Ellipsometer, Polarimeter And The Like Systems, Steven E. Green, Ping He, Galen L. Pfeiffer, Brian D. Guenther, Gerald T. Cooney, John A. Woollam, Martin M. Liphardt, Blaine D. Johs, Craig M. Herzinger Sep 2007

Sample Entry Purge System In Spectrophotometer, Ellipsometer, Polarimeter And The Like Systems, Steven E. Green, Ping He, Galen L. Pfeiffer, Brian D. Guenther, Gerald T. Cooney, John A. Woollam, Martin M. Liphardt, Blaine D. Johs, Craig M. Herzinger

Department of Electrical and Computer Engineering: Faculty Publications

A sample sequestering system which allows access to a subspace in a chamber encompassed generally enclosed space, for use in entering and removing a sample when the subspace is opened to atmosphere. Sufficient purge gas is flowed from withing the generally enclosed space into the subspace discourage atmospheric contaminates from entering into the space is a spectrophotometer, ellipsometer or polarimeter or the like system which operates at wavelengths, (eg. UV), which are advesely affected, (eg. absorded), by typical atmospheric contents.

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System For And Method Of Investigating The Exact Same Point On A Sample Substrate With Multiple Wavelengths, Galen L. Pfeiffer, Martin M. Liphardt, Blaine D. Johs, Craig M. Herzinger, Christopher A. Goeden, Ping He, John A. Woollam, James D. Welch May 2007

System For And Method Of Investigating The Exact Same Point On A Sample Substrate With Multiple Wavelengths, Galen L. Pfeiffer, Martin M. Liphardt, Blaine D. Johs, Craig M. Herzinger, Christopher A. Goeden, Ping He, John A. Woollam, James D. Welch

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed are system for and method of analyzing a sample at substantially the exact same small spot point on a sample with a plurality of wavelengths.

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System For And Method Of Investigating The Exact Same Point On A Sample Substrate With Multiple Wavelengths, Galen L. Pfeiffer, Martin M. Liphardt, Blaine D. Johs, Craig M. Herzinger, Christopher A. Goeden, Ping He, John A. Woollam, James D. Welch May 2007

System For And Method Of Investigating The Exact Same Point On A Sample Substrate With Multiple Wavelengths, Galen L. Pfeiffer, Martin M. Liphardt, Blaine D. Johs, Craig M. Herzinger, Christopher A. Goeden, Ping He, John A. Woollam, James D. Welch

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed are system for and method of analyzing a sample at Substantially the exact same Small spot point on a sample with a plurality of wavelengths.

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United States Patent Application Publication: System And Method For Sequence Distance Measure For Phylogenetic Tree Construction, K. Sayood, Hasan H. Otu, Steven H. Hinrichs Jan 2007

United States Patent Application Publication: System And Method For Sequence Distance Measure For Phylogenetic Tree Construction, K. Sayood, Hasan H. Otu, Steven H. Hinrichs

Department of Electrical and Computer Engineering: Faculty Publications

The present invention permits identification of biological materials following recovery of DNA using standard techniques by comparing a mathematical characterization of the unknown sequence with the mathematical characterization of DNA sequences of known genera and species. The clinical identification of infectious organisms is required for accurate diagnosis and selection of antimicrobial therapeutics. The invention allows an ab initio approach with the potential for rapid identification of biological materials of unknown origin. The approach provides for identification and classification of emergent or new organisms without previous phenotypic identification. The technique may also be used in monitoring situations where the need exists …

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Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb Communications, L. C. Tran, A. Mertins, Tadeusz A. Wysocki Jan 2007

Quasi-Orthogonal Space-Time-Frequency Codes In Mb-Ofdm Uwb Communications, L. C. Tran, A. Mertins, Tadeusz A. Wysocki

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

The paper examines the implementation of Quasi-Orthogonal Space-Time-Frequency Codes (QOSTFCs) to increase data rates and error performance in recently proposed STFC Multiband OFDM Ultra Wideband (MB-OFDM UWB) communications systems. It is shown that, an order-4 QOSTFC not only can provide the full rate, but also may provide significantly better error performance, compared to the conventional MB-OFDM (without STFCs), and considerably better error performance, compared to order-4, orthogonal STFC MBOFDM, without increasing the total transmission power.

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Design Of A 1.8v 8-Bit 500msps Folding-Interpolation Cmos A/D Converter With A Folder Averaging Technique, Dongjin Lee, Jaewon Song, Jongha Shin, Sanghoon Hwang, Minkyu Song, Tad Wysocki Jan 2007

Design Of A 1.8v 8-Bit 500msps Folding-Interpolation Cmos A/D Converter With A Folder Averaging Technique, Dongjin Lee, Jaewon Song, Jongha Shin, Sanghoon Hwang, Minkyu Song, Tad Wysocki

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

In this paper, a CMOS analog-to-digital converter (ADC) with an 8-bit 500MSPS at 1.8V is designed. The architecture of the proposed ADC is based on a Folding ADC with a cascaded-folding and a cascaded-interpolation structure. A self-linearized preamplifier with source degeneration technique and a folder averaging technique for the high-performance are introduced. Further, a novel auto-switching encoder is also proposed. The chip has been fabricated with 0.18μm 1-poly 5-metal CMOS technology. The active chip area is 0.79mm2 and it consumes about 200mW at 1.8V power supply. The DNL and INL are within ±0.6/±0.6LSB, respectively. The measured result of SNDR …

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A Bayesian Multilevel Modeling Approach For Data Query In Wireless Sensor Networks, Honggang Wang, Hua Fang, Kimberly A. Espy, Dongming Peng, Hamid Sharif Jan 2007

A Bayesian Multilevel Modeling Approach For Data Query In Wireless Sensor Networks, Honggang Wang, Hua Fang, Kimberly A. Espy, Dongming Peng, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

In power-limited Wireless Sensor Network (WSN), it is important to reduce the communication load in order to achieve energy savings. This paper applies a novel statistic method to estimate the parameters based on the real-time data measured by local sensors. Instead of transmitting large real-time data, we proposed to transmit the small amount of dynamic parameters by exploiting both temporal and spatial correlation within and between sensor clusters. The temporal correlation is built on the level-1 Bayesian model at each sensor to predict local readings. Each local sensor transmits their local parameters learned from historical measurement data to their cluster …

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C-Fos As A Proapoptotic Agent In Trail-Induced Apoptosis In Prostate Cancer Cells, Xiaoping Zhang, Liang Zhang, Hongmei Yang, Xu Huang, Hasan H. Otu, Towia A. Libermann, William C. Dewolf, Roya Khosravi-Far, Aria F. Olumi Jan 2007

C-Fos As A Proapoptotic Agent In Trail-Induced Apoptosis In Prostate Cancer Cells, Xiaoping Zhang, Liang Zhang, Hongmei Yang, Xu Huang, Hasan H. Otu, Towia A. Libermann, William C. Dewolf, Roya Khosravi-Far, Aria F. Olumi

Department of Electrical and Computer Engineering: Faculty Publications

Tumor necrosis factor–related apoptosis-inducing ligand (TRAIL)/Apo-2L promotes apoptosis in cancer cells while sparing normal cells. Although many cancers are sensitive to TRAIL-induced apoptosis, some evade the proapoptotic effects of TRAIL. Therefore, differentiating molecular mechanisms that distinguish between TRAIL-sensitive and TRAIL-resistant tumors are essential for effective cancer therapies. Here, we show that c-Fos functions as a proapoptotic agent by repressing the antiapoptotic molecule c-FLIP(L). c-Fos binds the c-FLIP(L) promoter, represses its transcriptional activity, and reduces c-FLIP(L) mRNA and protein levels. Therefore, c-Fos is a key regulator of c-FLIP(L), and activation of c-Fos determines whether a cancer cell will undergo cell death …

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Serum Proteome Profiling Detects Myelodysplastic Syndromes And Identifies Cxc Chemokine Ligands 4 And 7 As Markers For Advanced Disease, Manuel Aivado, Dimitrios Spentzos, Ulrich Germing, Gil Alterovitz, Xiao-Ying Meng, Franck Grall, Aristoteles A. N. Giagounidis, Giannoula Klement, Ulrich Steidl, Hasan H. Otu, Akos Czibere, Wolf C. Prall, Christof Iking-Konert, Michelle Shayne, Marco F. Ramoni, Norbert Gattermann, Rainer Haas, Constantine S. Mitsiades, Eric T. Fung, Towia A. Libermann Jan 2007

Serum Proteome Profiling Detects Myelodysplastic Syndromes And Identifies Cxc Chemokine Ligands 4 And 7 As Markers For Advanced Disease, Manuel Aivado, Dimitrios Spentzos, Ulrich Germing, Gil Alterovitz, Xiao-Ying Meng, Franck Grall, Aristoteles A. N. Giagounidis, Giannoula Klement, Ulrich Steidl, Hasan H. Otu, Akos Czibere, Wolf C. Prall, Christof Iking-Konert, Michelle Shayne, Marco F. Ramoni, Norbert Gattermann, Rainer Haas, Constantine S. Mitsiades, Eric T. Fung, Towia A. Libermann

Department of Electrical and Computer Engineering: Faculty Publications

Myelodysplastic syndromes (MDS) are among the most frequent hematologic malignancies. Patients have a short survival and often progress to acute myeloid leukemia. The diagnosis of MDS can be difficult; there is a paucity of molecular markers, and the pathophysiology is largely unknown. Therefore, we conducted a multicenter study investigating whether serum proteome profiling may serve as a noninvasive platform to discover novel molecular markers for MDS. We generated serum proteome profiles from 218 individuals by MS and identified a profile that distinguishes MDS from non-MDS cytopenias in a learning sample set. This profile was validated by testing its ability to …

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Collaborative Image Transmissions Based On Region And Path Diversity In Wireless Sensor Network, Honggang Wang, Dongming Peng, Wei Wang, Hamid Sharif, Hsiao-Hwa Chen Jan 2007

Collaborative Image Transmissions Based On Region And Path Diversity In Wireless Sensor Network, Honggang Wang, Dongming Peng, Wei Wang, Hamid Sharif, Hsiao-Hwa Chen

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Many Sensor applications such as monitoring and surveillance may require image sensor array to conduct collaborative image transmissions in Wireless Sensor Networks (WSN). The large size image transmissions cause bottlenecks in WSN due to the limited energy resources and network capacity. In this paper, we propose a collaborative transmission scheme for image sensors to utilize inter-sensor correlations to decide transmission patterns based on transmission path diversities, which achieves minimal energy consumption, balanced sensor lifetime and required image quality. This optimization scheme not only allows each image sensor to transmit optimal fractions of the overlapped images through appropriate transmission paths in …

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A Small Chip Area 12-B 300ms/S Current Steering Cmos D/A Converter Based On A Laminated-Step Layout Technique, Byungseung Lee, Byungill Kim, Juneseok Lee, Sanghoon Hwang, Minkyu Song, Tad Wysocki Jan 2007

A Small Chip Area 12-B 300ms/S Current Steering Cmos D/A Converter Based On A Laminated-Step Layout Technique, Byungseung Lee, Byungill Kim, Juneseok Lee, Sanghoon Hwang, Minkyu Song, Tad Wysocki

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

A 12-b 300MSPS Current-Steering DAC with 0.13um CMOS technology is presented. In order to reduce the chip area, a laminated-step layout technique is proposed. Based on this technique, the occupied DAC core size is only 0.26mm2 even in 12-b resolution. Further, a current auto-averaging technique, an output impedance enhancement circuit, and the novel latched switching cell logic are discussed to keep the desired 12- b DAC performance. The measured results are within ±1LSB for DNL. The measured SFDR is 70dB under Nyquist output frequency with 50mW power dissipation at 3.3V power supply.

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A Simple Orthogonal Space-Time-Polarization Block Code, B. J. Wysocki, Tadeusz Wysocki, J. Seberry, S. Spence Adams, H. Sharif Jan 2007

A Simple Orthogonal Space-Time-Polarization Block Code, B. J. Wysocki, Tadeusz Wysocki, J. Seberry, S. Spence Adams, H. Sharif

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

This letter proposes a simple but highly efficient technique to jointly utilize space, time, and polarization diversities. The technique is based on extending orthogonal space-time block codes into the quaternion domain and utilizing a description of the dual-polarized signal by means of quaternions, which are a generalization of complex numbers. In the given example, the achievable performance gain for two transmit and one receive antennas is approximately 6 dB at a bit error rate of 10-4 when compared with the Alamouti code.

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Direct Sequence Modified Time Hopping Ppm Over Ultra Wideband S-V Channel, Peter Vial, Beata J. Wysocki, Tadeusz A. Wysocki Dec 2006

Direct Sequence Modified Time Hopping Ppm Over Ultra Wideband S-V Channel, Peter Vial, Beata J. Wysocki, Tadeusz A. Wysocki

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

A three position Pulse Position Modulation (PPM) scheme is proposed for a Direct Sequence Time Hopping Ultra Wideband wireless communication system. The channel is based on the Saleh-Valenzuela model. We show that by adapting the Space Time Spreading technique to use three pulse positions in a single input single output system representing -2,0,2 an improvement in Bit Error Rate is achieved compared to sending the same bits using two pulse positions only. In addition, the bit access rate is doubled as two bits can be successfully sent in the same time using our proposed system.

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An Energy Efficient Mac-Phy Approach To Support Distributed Source Coding In Wireless Sensor Network, Wei Wang, Dongming Peng, Honggang Wang, Hamid Sharif, Beata J. Wysocki, Tadeusz A. Wysocki Dec 2006

An Energy Efficient Mac-Phy Approach To Support Distributed Source Coding In Wireless Sensor Network, Wei Wang, Dongming Peng, Honggang Wang, Hamid Sharif, Beata J. Wysocki, Tadeusz A. Wysocki

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Distributed Source Coding (DSC) based signal processing applications are ideal candidates for multirate transmissions in Wireless Sensor Network (WSN). In this paper, we propose a novel MAC-PHY approach in WSN to achieve energy efficiency using multirate desirable for the DSC based signal processing applications. Our approach is different from the common multirate research in link adaptation, the focus of which is to increase throughput based on rate adaptation derived from variable channel conditions. In the proposed approach, the redundant and inefficient communications are eliminated, yielding significant improvement of energy efficiency in WSN. Here, the minimum desirable transmission power can be …

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Capacity Of Single-Radio Ad Hoc Networks For Handling High Bit-Rate Real-Time Internet Applications, Mehran Abolhasan, Tadeusz A. Wysocki, Daniel Franklin, Justin Lipman Dec 2006

Capacity Of Single-Radio Ad Hoc Networks For Handling High Bit-Rate Real-Time Internet Applications, Mehran Abolhasan, Tadeusz A. Wysocki, Daniel Franklin, Justin Lipman

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Until now, the main focus in ad hoc networking has been improving Routing and Medium Access Control (MAC) Strategies. As a result, a diverse range of routing and MAC protocols have been proposed. To evaluate these protocols, much of the existing research has been based on simulation scenarios which assume ideal channel conditions and low node and traffic densities. Therefore, despite a few studies which have shown the performance limitations of ad hoc networks theoretically, there has not been many simulation studies performed which investigate the performance of ad hoc networks under a high node and traffic density. This paper …

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Multi-User Uwb-Ir Systems With Interleaved Coding-Modulation On Multipath Fading Channels, Michal M. Pietrzyk, Keni Popovski, Tadeusz Wysocki, Beata J. Wysocki, Jos H. Weber Nov 2006

Multi-User Uwb-Ir Systems With Interleaved Coding-Modulation On Multipath Fading Channels, Michal M. Pietrzyk, Keni Popovski, Tadeusz Wysocki, Beata J. Wysocki, Jos H. Weber

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Interleaved coding-modulation (ICM) is a recently proposed method for ultra-wideband impulse radio (UWBIR) systems. ICM exploits the concept of chip interleaving, allowing to alleviate the problem of inter-symbol and inter-pulse interference commonly present in high data rate UWB-IR systems. In this paper, we extend previous work on ICM to scarcely populated multi-user scenarios. We propose a design of a deterministic chip interleaver based on time-hopping hyperbolic congruence sequences. We also review the main parameters of the random and hyperbolic interleavers. Our results indicate that the proposed type of interleaver yields similar performance to random interleavers but with the advantage of …

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Adaptive Interpolation Algorithms For Temporal-Oriented Datasets, Jun Gao Jun 2006

Adaptive Interpolation Algorithms For Temporal-Oriented Datasets, Jun Gao

School of Computing: Dissertations, Theses, and Student Research

Spatiotemporal datasets can be classified into two categories: temporal-oriented and spatial-oriented datasets depending on whether missing spatiotemporal values are closer to the values of its temporal or spatial neighbors. We present an adaptive spatiotemporal interpolation model that can estimate the missing values in both categories of spatiotemporal datasets. The key parameters of the adaptive spatiotemporal interpolation model can be adjusted based on experience.

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Spectrophotometer, Ellipsometer, Polarmeter And The Like Systems, John A. Woollam, Steven E. Green, Ping He, Blaine D. Johs, Craig M. Herzinger, Galen L. Pfeiffer, Brian D. Guenther, Martin M. Liphardt Jan 2006

Spectrophotometer, Ellipsometer, Polarmeter And The Like Systems, John A. Woollam, Steven E. Green, Ping He, Blaine D. Johs, Craig M. Herzinger, Galen L. Pfeiffer, Brian D. Guenther, Martin M. Liphardt

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed are improvements in ellipsometer and the like systems capable of operating in the Vacuum-Ultra-Violet (VUV) to Near Infrared (NIR) wavelength range, and methodology of use.

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Human Transcriptome Corresponding To Human Oocytes And Use Of Said Genes Or The Corresponding Polypeptides To Trans-Differentiate Somatic Cells, Jose Bernardo Cibelli, Arif Murat Kocabas, Bing Lim, Hasan H. Otu Jan 2006

Human Transcriptome Corresponding To Human Oocytes And Use Of Said Genes Or The Corresponding Polypeptides To Trans-Differentiate Somatic Cells, Jose Bernardo Cibelli, Arif Murat Kocabas, Bing Lim, Hasan H. Otu

Department of Electrical and Computer Engineering: Faculty Publications

The identification of 101 genes upregulated or differentially expressed by mature human oocytes is provided herein. These genes and the corresponding gene products will facilitate a greater understanding of oogenesis, folliculogenesis, fertilization, and embryonic development. In addition these genes and the corresponding gene products can be used to effect dedifferentiation and/or transdifferentiation of desired somatic cells. The resultant dedifferentiated cells and somatic cells derived therefrom can be used in cell therapies such as in the treatment of cancer, autoimmunity, and other diseases wherein specific types of cells such as hematopoietic cells may be depleted because of the underlying disease or …

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Complex Orthogonal Spreading Sequences Using Mutually Orthagonal Complimentary Sets, Ying Zhao, Jennifer Seberry, Beata J. Wysocki, Tadeusz Wysocki Jan 2006

Complex Orthogonal Spreading Sequences Using Mutually Orthagonal Complimentary Sets, Ying Zhao, Jennifer Seberry, Beata J. Wysocki, Tadeusz Wysocki

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

This paper presents a new family of complex spreading sequences designed using mutually orthogonal(MO) complementary sets. Based on the technique described in this paper, the correlation properties of sets of sequences are compared to well-known Walsh-Hadamard sequence sets. Further improvement of correlation qualities can be achieved by employing a diagonal modification method. We also present simulation results of an asynchronous multiuser CDMA system using the modified sequences.

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Scarcely Populated Uwb-Ir Systems With Interleaved Coding-Modulation On Multipath Fading Channels, Michal M. Pietrzyk, Keni Popovski, Tadeusz Wysocki, Beata J. Wysocki, Jos H. Weber Jan 2006

Scarcely Populated Uwb-Ir Systems With Interleaved Coding-Modulation On Multipath Fading Channels, Michal M. Pietrzyk, Keni Popovski, Tadeusz Wysocki, Beata J. Wysocki, Jos H. Weber

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Interleaved coding-modulation (ICM) is a recently proposed method for ultra-wideband impulse radio (UWBIR) systems. ICM exploits the concept of chip interleaving, allowing to alleviate the problem of inter-symbol and inter-pulse interference commonly present in high data rate UWB-IR systems. In this paper, previous work on ICM is extended to scarcely populated multi-user scenarios. A novel design of a deterministic chip interleaver based on time-hopping hyperbolic congruence sequences is proposed. Furthermore, the main parameters of the random and hyperbolic interleavers are reviewed. The obtained results indicate that the proposed type of interleaver yields similar performance to random interleavers but with the …

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Performance Comparison Ofuwb Hopping Codes In A Multi-User Rich Scattering Environment, K. Popovski, B. J. Wysocki, Tadeusz Wysocki Jan 2006

Performance Comparison Ofuwb Hopping Codes In A Multi-User Rich Scattering Environment, K. Popovski, B. J. Wysocki, Tadeusz Wysocki

Department of Electrical and Computer Engineering: Faculty Publications (to 2015)

Ultra Wideband is a short-range wireless communication technique which has seen increased interest over the past decade. Having several methods of implementation, a key issue will always be the avoidance of multi-user interference. For time-hopped Ultra Wideband, this is achieved through the use of different codes assigned to each user, performing time-hopped code division multiple access.
This paper presents a performance comparison of several time hopping sequence construction methods. It presents correlation results between sequences, and simulation results in a Gaussian noise degraded, scattering rich multi-user environment. Simulations are based on the IEEE channel model for UWB communications.

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On-Off Frequency-Shift Keying For Wideband Fading Channels, Mustafa Cenk Gursoy, H. Vincent Poor, Sergio Verdu Jan 2006

On-Off Frequency-Shift Keying For Wideband Fading Channels, Mustafa Cenk Gursoy, H. Vincent Poor, Sergio Verdu

Department of Electrical and Computer Engineering: Faculty Publications

M-ary on-off frequency-shift keying (OOFSK) is a digital modulation format in which M-ary FSK signaling is overlaid on on/off keying. This paper investigates the potential of this modulation format in the context of wideband fading channels. First, it is assumed that the receiver uses energy detection for the reception of OOFSK signals. Capacity expressions are obtained for the cases in which the receiver has perfect and imperfect fading side information. Power efficiency is investigated when the transmitter is subject to a peak-to-average power ratio (PAR) limitation or a peak power limitation. It is shown that under a PAR limitation, it …

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The Transcriptome Of Human Oocytes, Arif Murat Kocabas, Javier Crosby, Pablo J. Ross, Hasan H. Otu, Zeki Beyhan, Handan Can, Wai-Leong Tam, Guilherme J. M. Rosa, Robert G. Halgren, Bing Lim, Emilio Fernandez, Jose Bernardo Cibelli Jan 2006

The Transcriptome Of Human Oocytes, Arif Murat Kocabas, Javier Crosby, Pablo J. Ross, Hasan H. Otu, Zeki Beyhan, Handan Can, Wai-Leong Tam, Guilherme J. M. Rosa, Robert G. Halgren, Bing Lim, Emilio Fernandez, Jose Bernardo Cibelli

Department of Electrical and Computer Engineering: Faculty Publications

The identification of genes and deduced pathways from the mature human oocyte can help us better understand oogenesis, folliculogenesis, fertilization, and embryonic development. Human metaphase II oocytes were used within minutes after removal from the ovary, and its transcriptome was compared with a reference sample consisting of a mixture of total RNA from 10 different normal human tissues not including the ovary. RNA amplification was performed by using a unique protocol. Affymetrix Human Genome U133 Plus 2.0 GeneChip arrays were used for hybridizations. Compared with reference samples, there were 5,331 transcripts significantly up-regulated and 7,074 transcripts significantly down-regulated in the …

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Energy-Constrained Quality Optimization For Secure Image Transmission In Wireless Sensor Networks, Wei Wang, Dongming Peng, Honggang Wang, Hamid Sharif, Hsiao-Hwa Chen Jan 2006

Energy-Constrained Quality Optimization For Secure Image Transmission In Wireless Sensor Networks, Wei Wang, Dongming Peng, Honggang Wang, Hamid Sharif, Hsiao-Hwa Chen

Department of Electrical and Computer Engineering: Faculty Publications

Resource allocation for multimedia selective encryption and energy efficient transmission has not been fully investigated in literature for wireless sensor networks (WSNs). In this article, we propose a new cross-layer approach to optimize selectively encrypted image transmission quality in WSNs with strict energy constraint. A new selective image encryption approach favorable for unequal error protection (UEP) is proposed, which reduces encryption overhead considerably by controlling the structure of image bitstreams. Also, a novel cross-layer UEP scheme based on cipher-plain-text diversity is studied. In this UEP scheme, resources are unequally and optimally allocated in the encrypted bitstream structure, including data position …

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