Electrical and Computer Engineering Commons^™

Overview Of Lte Spectrum Sharing Technologies, Yun Ye, Dalei Wu, Zhihui Shu, Yi Qian

Department of Electrical and Computer Engineering: Faculty Publications

Long-Term Evolution (LTE) communication systems feature advanced frequency reuse and interference coordination techniques providing faster and more secured mobile services. However, the network capacity in licensed spectrum is still behind market demands. Dynamic spectrum access or spectrum sharing in other frequently vacant or unlicensed frequency bands is considered an effective means to boost system throughput. Different from operations in licensed spectrum with exclusive access, LTE deployment needs to take into account the distinct regulations on channel access to each shared frequency band, in order to avoid interference to incumbent users, and to maintain fair play with peer operators in heterogeneous …

Control Of Networked Systems With Engineering Applications, Housheng Su, Michael Z.Q. Chen, Qing Hui, Yuan Fan, Zhiwei Gao

Department of Electrical and Computer Engineering: Faculty Publications

Recently, control of networked systems problems has attracted much attention among researchers in biology, physics, control engineering, and computer science for decades, partially due to the broad applications of control of networked systems in many engineering areas including cooperative control of mobile robots and estimation of mobile sensor networks. The study of complex network topology and modeling is to understand the influence of network structure on its function and consequently to find effective ways to improve network performance.

This special issue focuses on theoretical and technological achievements in control of networked systems. The contents of the accepted papers are summarized …

Reconfigurable Battery Techniques And Systems: A Survey, Song Ci, Ni Lin, Dalei Wu

Department of Electrical and Computer Engineering: Faculty Publications

Battery packs with a large number of battery cells are becoming more and more widely adopted in electronic systems, such as robotics, renewable energy systems, energy storage in smart grids, and electronic vehicles. Therefore, a well-designed battery pack is essential for battery applications. In the literature, the majority of research in battery pack design focuses on battery management system, safety circuit, and cell-balancing strategies. Recently, the reconfigurable battery pack design has gained increasing attentions as a promising solution to solve the problems existing in the conventional battery packs and associated battery management systems, such as low energy efficiency, short pack …

Detecting Faults In Turbine Generators, Wei Qiao, Xiang Gong

Department of Electrical and Computer Engineering: Faculty Publications

Turbine generator faults can be detected by receiving a current signal from the turbine generator, and synchronously sampling the current signal to obtain a set of current signal samples that are evenly spaced in the phase domain, in which phase differences between adjacent current signal samples in the set of current signal samples are substantially the same. The process includes generating a frequency spectrum of the current signal samples, identifying one or more excitations in the frequency spectrum, and detecting a fault in the turbine generator based on the one or more excitations in the frequency spectrum.

Anisotropy, Band-To-Band Transitions, Phonon Modes, And Oxidation Properties Of Cobalt-Oxide Core-Shell Slanted Columnar Thin Films, Alyssa Mock, Rafał Korlacki, Chad Briley, Derek Sekora, Tino Hofmann, Peter Wilson, Alexander Sinitskii, Eva Schubert, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

Highly ordered and spatially coherent cobalt slanted columnar thin films (SCTFs) were deposited by glancing angle deposition onto silicon substrates, and subsequently oxidized by annealing at 475˚C. Scanning electron microscopy, Raman scattering, generalized ellipsometry, and density functional theory investigations reveal shape-invariant transformation of the slanted nanocolumns from metallic to transparent metal-oxide core-shell structures with properties characteristic of spinel cobalt oxide. We find passivation of Co-SCTFs yielding Co-Al₂O₃ core-shell structures produced by conformal deposition of a few nanometers of alumina using atomic layer deposition fully prevents cobalt oxidation in ambient and from annealing up to 475˚C.

Sticking With The Pointy End? Molecular Configuration Of Chloro Boron-Subphthalocyanine On Cu(111), Nahid Ilyas, Shashank S. Harivyasi, Percy Zahl, Rocio Cortes, Oliver T. Hofmann, Peter Sutter, Egbert Zojer, Oliver L. A. Monti

Department of Electrical and Computer Engineering: Faculty Publications

In this combined low-temperature scanning tunneling microscopy (STM) and density functional theory (DFT) study, we investigate self-assembly of the dipolar nonplanar organic semiconductor chloro boron-subphthalocyanine (ClB-SubPc) on Cu(111). We observe multiple distinct adsorption configurations and demonstrate that these can only be understood by taking surface-catalyzed dechlorination into account. A detailed investigation of possible adsorption configurations and the comparison of experimental and computational STM images demonstrates that the configurations correspond to “Cl-up” molecules with the B− Cl moiety pointing toward the vacuum side of the interface, and dechlorinated molecules. In contrast to the standard interpretation of adsorption of nonplanar molecules in …

Detecting Microbial Dysbiosis Associated With Pediatric Crohn Disease Despite The High Variability Of The Gut Microbiota, Feng Wang, Jess L. Kaplan, Benjamin D. Gold, Manoj K. Bhasin, Naomi L. Ward, Richard Kellermayer, Barbara S. Kirschner, Melvin B. Heyman, Scot E. Dowd, Stephen B. Cox, Haluk Dogan, Blaire Steven, George Ferry, Stanley A. Cohen, Robert N. Baldassano, Christopher J. Moran, Elizabeth A. Garnett, Lauren Drake, Hasan H. Otu, Leonid A. Mirny, Towia A. Libermann, Harland S. Winter, Kirill S. Korolev

Department of Electrical and Computer Engineering: Faculty Publications

The relationship between the host and its microbiota is challenging to understand because both microbial communities and their environments are highly variable. We have developed a set of techniques based on population dynamics and information theory to address this challenge. These methods identify additional bacterial taxa associated with pediatric Crohn disease and can detect significant changes in microbial communities with fewer samples than previous statistical approaches required. We have also substantially improved the accuracy of the diagnosis based on the microbiota from stool samples, and we found that the ecological niche of a microbe predicts its role in Crohn disease. …

A Survey Of Wireless Communication Technologies & Their Performance For High Speed Railways, Subharthi Banerjee, Michael Hempel, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications

High Speed Railway (HSR) provides its customers not only safety, security, comfort and on-time commuting, but also a fast transportation alternative to air travel or regular passenger rail services. Providing these benefits would not be possible without the tremendous growth and prevalence of wireless communication technologies. Due to advances in wireless communication systems, both trains and passengers are connected through high speed wireless networks to the Internet, data centers and railroad control centers. Railroad communities, academia, related industries and standards bodies, even the European Space Agency, are involved in advancing developments of HSR for highly connected train communication systems. The …

Development Of A Compact Vertical-Cavity Surface-Emitting Laser End-Pumped Actively Q-Switched Laser For Laser-Induced Breakdown Spectroscopy, Shuo Li, L. Liu, Rongzhang Chen, Bryan Nelsen, Xi Huang, Yongfeng Lu, Kevin Chen

Department of Electrical and Computer Engineering: Faculty Publications

This paper reports the development of a compact and portable actively Q-switched Nd:YAG laser and its applications in laser-induced breakdown spectroscopy (LIBS). The laser was end-pumped by a vertical-cavity surface-emitting laser (VCSEL). The cavity lases at a wavelength of 1064 nm and produced pulses of 16 ns with a maximum pulse energy of 12.9 mJ. The laser exhibits a reliable performance in terms of pulse-to-pulse stability and timing jitter. The LIBS experiments were carried out using this laser on NIST standard alloy samples. Shot-to-shot LIBS signal stability, crater profile, time evolution of emission spectra, plasma electron density and temperature, and …

Hybrid Quantum Dot-Tin Disulfide Field-Effect Transistors With Improved Photocurrent And Spectral Responsivity, Yuan Huang, Huidong Zang, Jia -Shiang Chen, Eli Sutter, Peter Sutter, Chang- Yong Nam, Mircea Cotlet

Department of Electrical and Computer Engineering: Faculty Publications

We report an improved photosensitivity in few-layer tin disulfide (SnS2) field-effect transistors (FETs) following doping with CdSe/ZnS core/shell quantum dots (QDs). The hybrid QD-SnS₂ FET devices achieve more than 500% increase in the photocurrent response compared with the starting SnS₂-only FET device and a spectral responsivity reaching over 650 A/W at 400 nm wavelength. The negligible electrical conductance in a control QD-only FET device suggests that the energy transfer between QDs and SnS₂ is the main mechanism responsible for the sensitization effect, which is consistent with the strong spectral overlap between QD photoluminescence and SnS_{2 …}

Alloy Oxidation As A Route To Chemically Active Nanocomposites Of Gold Atoms In A Reducible Oxide Matrix, Peter Sutter, S. A. Tenney, F. Ivars- Barcelo, L. Wu, Y. Zhu, Eli Sutter

Department of Electrical and Computer Engineering: Faculty Publications

While nanoparticles are being pursued actively for a number of applications, dispersed atomic species have been explored far less in functional materials architectures, primarily because composites comprising dispersed atoms are challenging to synthesize and difficult to stabilize against sintering or coarsening. Here we show that room temperature oxidation of Au–Sn alloys produces nanostructures whose surface is terminated by a reducible amorphous oxide that contains atomically dispersed Au. Analysis of the oxidation process shows that the dispersal of Au in the oxide can be explained by predominant oxygen anion diffusion and kinetically limitedmetalmass transport, which restrict phase separation due to a …

Enhanced Four-Wave Mixing With Nonlinear Plasmonic Metasurfaces, Boyuan Jin, Christos Argyropoulos

Department of Electrical and Computer Engineering: Faculty Publications

Plasmonic metasurfaces provide an effective way to increase the efficiency of several nonlinear processes while maintaining nanoscale dimensions. In this work, nonlinear metasurfaces based on film-coupled silver nanostripes loaded with Kerr nonlinear material are proposed to achieve efficient four-wave mixing (FWM). Highly localized plasmon resonances are formed in the nanogap between the metallic film and nanostripes. The local electric field is dramatically enhanced in this subwavelength nanoregion. These properties combined with the relaxed phase matching condition due to the ultrathin area lead to a giant FWM efficiency, which is enhanced by nineteen orders of magnitude compared to a bare silver …

Broadband Compact Microstrip Patch Antenna Design Loaded By Multiple Split Ring Resonator Superstrate And Substrate, Shobhit K. Patel, Christos Argyropoulos, Yogeshwar P. Kosta

Department of Electrical and Computer Engineering: Faculty Publications

We present microstrip patch antenna loaded with multiple split ring resonator substrate and superstrate. We analyze how the loading of split ring resonator superstrate and substrate can improve the bandwidth compared to the simple microstrip patch antenna and microstrip patch antenna loaded with split ring resonator superstrate. Another important observation is made for multiple split ring resonator loading in superstrate and substrate of microstrip patch antenna. The design is compared for two, three, and four-ring split ring resonator loading. The designs are also compared for different gap spacing between the rings. All three designs are compared for small gap and …

Meta-Analysis Of Transcriptome Data Identifies A Novel 5-Gene Pancreatic Adenocarcinoma Classifier, Manoj K. Bhasin, Kenneth Ndebele, Octavian Bucur, Eric U. Yee, Hasan H. Otu, Jessica Plati, Andrea Bullock, Xuesong Gu, Eduardo Castan, Peng Zhang, Robert Najarian, Maria S. Muraru, Rebecca Miksad, Roya Khosravi-Far, Towia A. Libermann

Department of Electrical and Computer Engineering: Faculty Publications

Purpose: Pancreatic ductal adenocarcinoma (PDAC) is largely incurable due to late diagnosis. Superior early detection biomarkers are critical to improving PDAC survival and risk stratification.

Experimental Design: Optimized meta-analysis of PDAC transcriptome datasets identified and validated key PDAC biomarkers. PDAC-specific expression of a 5-gene biomarker panel was measured by qRT-PCR in microdissected patient-derived FFPE tissues. Cell-based assays assessed impact of two of these biomarkers, TMPRSS4 and ECT2, on PDAC cells.

Results: A 5-gene PDAC classifier (TMPRSS4, AHNAK2, POSTN, ECT2, SERPINB5) achieved on average 95% sensitivity and 89% specificity in discriminating PDAC from non-tumor samples in four training sets and similar …

Special Issue On Survivable And Resilient Communication Networks And Services, Eytan Modiano, Rudra Dutta, Yi Qian

Department of Electrical and Computer Engineering: Faculty Publications

Communication networks and services play a vital role in our modern lives. This importance is expected to continue to grow in future decades. More and more business, healthcare or government organizations will become increasingly dependent on the communication between their offices and people. Not only does modern society depend on these services in terms of availability but also in terms of proper functioning in all circumstances. These services having stringent requirements with respect to protection of privacy and security. Anonymity (such as e-health) cannot accept, for example, temporary leakage of confidential information by accident whether a result of human error …

Coordinate-Invariant Lyddane-Sachs-Teller Relationship For Polar Vibrations In Materials With Monoclinic And Triclinic Crystal Systems, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

A coordinate-invariant generalization of the Lyddane-Sachs-Teller relation is presented for polar vibrations in materials with monoclinic and triclinic crystal systems. The generalization is derived from an eigendielectric displacement vector summation approach, which is equivalent to the microscopic Born-Huang description of polar lattice vibrations in the harmonic approximation. An expression for a general oscillator strength is also described for materials with monoclinic and triclinic crystal systems. A generalized factorized form of the dielectric response characteristic for monoclinic and triclinic materials is proposed. The generalized Lyddane-Sachs-Teller relation is found valid for monoclinic β-Ga2O3, where accurate experimental data became available recently from a …

Dst Approach To Enhance Audio Quality On Lost Audio Packet Steganography, Qilin Qi, Dongming Peng, Hamid Sharif

Department of Electrical and Computer Engineering: Faculty Publications

Lost audio packet steganography (LACK) is a steganography technique established on the VoIP network. LACK provides a high-capacity covert channel over VoIP network by artificially delaying and dropping a number of packets in use to convey stegnogram. However, the increasing loss of packets will hurt the quality of the VoIP service. The quality deterioration will not only affect the legitimate VoIP service but also constrain the capacity of the covert channel. Discrete spring transform (DST) is proven to be a way to eliminate the perceptual redundancy in the multimedia signal. In this paper, the DST is applied on the LACK …

Distinct And Shared Determinants Of Cardiomyocyte Contractility In Multi-Lineage Competent Ethnically Diverse Human Ipscs, Martin L. Tomov, Zachary T. Olmsted, Haluk Dogan, Eda Gongorurler, Maria Tsompana, Hasan H. Otu, Michael Buck, Eun-Ah Chang, Jose Cibelli, Janet L. Paluh

Department of Electrical and Computer Engineering: Faculty Publications

The realization of personalized medicine through human induced pluripotent stem cell (iPSC) technology can be advanced by transcriptomics, epigenomics, and bioinformatics that inform on genetic pathways directing tissue development and function. When possible, population diversity should be included in new studies as resources become available. Previously we derived replicate iPSC lines of African American, Hispanic-Latino and Asian self-designated ethnically diverse (ED) origins with normal karyotype, verified teratoma formation, pluripotency biomarkers, and tri-lineage in vitro commitment. Here we perform bioinformatics of RNA-Seq and ChIP-seq pluripotency data sets for two replicate Asian and Hispanic-Latino ED-iPSC lines that reveal differences in generation of …

Embeddable Advanced Sensors For Harsh Environment Sensing Applications, Lei Yuan, Yinan Zhang, Yan Lu, Xiaobei Zhang, Mengmeng Wang

Department of Electrical and Computer Engineering: Faculty Publications

Research and development in advanced sensors with embedded monitoring capability have experienced significant growth in recent years, fueled by their broad applications in real-time measurement of a wide variety of physical, chemical, and biological quantities. Compared with conventional sensors with bulky assemblies, recent progress in 3D manufacturing technologies (e.g., ultrafast laser micromachining and additive manufacturing) has opened up a new avenue in one-step fabrication of assembly-freemicro devices in various materials as well as the development of compact, customized, and intricate smart structures/components. The merits of these advanced manufacturing techniques enable the integration of embeddable advanced sensors into smart structures and …

A Wideband And Polarization-Independent Metasurface Based On Phase Optimization For Monostatic And Bistatic Radar Cross Section Reduction, Jianxun Su, Yao Lu, Zengrui Li, Rongrong Zhang, Yaoqing (Lamar) Yang

Department of Electrical and Computer Engineering: Faculty Publications

A broadband and polarization-independent metasurface is analyzed and designed for both monostatic and bistatic radar cross section (RCS) reduction in this paper. Metasurfaces are composed of two types of electromagnetic band-gap (EBG) lattice, which is a subarray with “0” or “𝜋” phase responses, arranged in periodic and aperiodic fashions. A new mechanism is proposed for manipulating electromagnetic (EM) scattering and realizing the best reduction of monostatic and bistatic RCS by redirecting EM energy to more directions through controlling the wavefront of EMwave reflected from the metasurface. Scattering characteristics of two kinds of metasurfaces, periodic arrangement and optimized phase layout, are …

A Wideband End-Fire Conformal Vivaldi Antenna Array Mounted On A Dielectric Cone, Zengrui Li, Xiaole Kang, Jianxun Su, Qingxin Guo, Yaoqing (Lamar) Yang, Junhong Wang

Department of Electrical and Computer Engineering: Faculty Publications

The characteristics of a novel antipodal Vivaldi antenna array mounted on a dielectric cone are presented. By employing antipodal Vivaldi antenna element, the antenna array shows ultrawide bandwidth and end-fire radiation characteristics.Our simulations show that the cone curvature has an obvious influence on the performance of the conformal antenna, in terms of both the bandwidth and the radiation patterns. The thickness and permittivity of the dielectric cone have an effect on the bandwidth of the conformal antenna. Measurement results of both single antenna and conformal antenna array show a good agreement with the simulated results. The measured conformal antenna can …

Anisotropy, Band-To-Band Transitions, Phonon Modes, And Oxidation Properties Of Cobalt-Oxide Core-Shell Slanted Columnar Thin Films, Alyssa Mock, Rafał Korlacki, Chad Briley, Derek Sekora, Tino Hofmann, Peter M. Wilson, Alexander Sinitskii, Eva Schubert, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

Highly ordered and spatially coherent cobalt slanted columnar thin films (SCTFs) were deposited by glancing angle deposition onto silicon substrates, and subsequently oxidized by annealing at 475°C. Scanning electron microscopy, Raman scattering, generalized ellipsometry, and density functional theory investigations reveal shape-invariant transformation of the slanted nanocolumns from metallic to transparent metal-oxide core-shell structures with properties characteristic of spinel cobalt oxide. We find passivation of Co-SCTFs yielding Co-Al₂O₃core-shell structures produced by conformal deposition of a few nanometers of alumina using atomic layer deposition fully prevents cobalt oxidation in ambient and from annealing up to 475°C.

Anisotropy, Phonon Modes, And Free Charge Carrier Parameters In Monoclinic Β-Gallium Oxide Single Crystals, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

We derive a dielectric function tensor model approach to render the optical response of monoclinic and triclinic symmetrymaterials with multiple uncoupled infrared and far-infrared active modes.We apply our model approach to monoclinic β-Ga₂O₃ single-crystal samples. Surfaces cut under different angles from a bulk crystal, (010) and (201), are investigated by generalized spectroscopic ellipsometry within infrared and far-infrared spectral regions. We determine the frequency dependence of 4 independent β-Ga₂O₃ Cartesian dielectric function tensor elements by matching large sets of experimental data using a point-by-point data inversion approach. From matching our monoclinic model to …