Computer Engineering Commons^™

Luminescence Of Defects In The Structural Transformation Of Layered Tin Dichalcogenides, Peter Sutter, H.P. Komsa, A. V. Krasheninnikov, Y Huang, Eli A. Sutter

Department of Electrical and Computer Engineering: Faculty Publications

Layered tin sulfide semiconductors are both of fundamental interest and attractive for energy conversion applications. Sn sulfides crystallize in several stable bulk phases with different Sn:S ratios (SnS2, Sn2, S3, and SnS), which can transform into phases with a lower sulfur concentration by introduction of sulfur vacancies (VS). How this complex behavior affects the optoelectronic properties remains largely unknown but is of key importance for understanding light-matter interactions in this family of layered materials. Here, we use the capability to induce VS and drive a transformation between few-layer SnS2 and SnS by electron beam irradiation, combined with in-situ cathodoluminescence spectroscopy …

Condensation And Subsequent Freezing Delays As A Result Of Using A Femtosecond Laser Functionalized Surface, Chongji Huang

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Femtosecond laser surface processing (FLSP) enhances the anti-icing properties of a commonly used aircraft alloy, Al 7075-O Clad. The wettability of Al 7075-O Clad was altered by changing the surface morphology through FLSP and the surface chemistry through siloxane vapor deposition. Tall mound and short mound FLSP functionalized surfaces were created through two sets of laser parameters. Atmospheric condensation and subsequent freezing of condensates on FLSP Al 7075-O Clad was studied. Results indicate that both structure height and surface wettability play a role in the delay of freezing. Freezing occurred on the FLSP superhydrophilic surface faster than on a unprocessed …

Anti-Icing Properties Of Femtosecond Laser Surface Processed Material, Ryan James Bell

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

In this thesis, the use of femtosecond laser surface processing (FLSP) to enhance the anti-icing properties of a commonly used aircraft alloy, Al 7075-O Clad is described. By changing the surface morphology through FLSP and the surface chemistry through siloxane vapor deposition, the wettability of Al 7075-O Clad was altered.

Condensation and the subsequent freezing of condensates on FLSP Al 7075-O Clad was studied. Both structure height and surface wettability were shown to play a role in the delay of freezing. Freezing occurred on the FLSP superhydrophilic surface faster than on the unprocessed Al 7075-O Clad surface, however, freezing was …

Event And Time-Triggered Control Module Layers For Individual Robot Control Architectures Of Unmanned Agricultural Ground Vehicles, Tyler Troyer

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Automation in the agriculture sector has increased to an extent where the accompanying methods for unmanned field management are becoming more economically viable. This manifests in the industry’s recent presentation of conceptual cab-less machines that perform all field operations under the high-level task control of a single remote operator. A dramatic change in the overall workflow for field tasks that historically assumed the presence of a human in the immediate vicinity of the work is predicted. This shift in the entire approach to farm machinery work provides producers increased control and productivity over high-level tasks and less distraction from operating …

Security For 5g Mobile Wireless Networks, Dongfeng Fang, Yi Qian, Rose Qingyang Hu

Department of Electrical and Computer Engineering: Faculty Publications

The advanced features of 5G mobile wireless network systems yield new security requirements and challenges. This paper presents a comprehensive survey on security of 5G wireless network systems compared to the traditional cellular networks. The paper starts with a review on 5G wireless networks particularities as well as on the new requirements and motivations of 5G wireless security. The potential attacks and security services with the consideration of new service requirements and new use cases in 5G wireless networks are then summarized. The recent development and the existing schemes for the 5G wireless security are presented based on the corresponding …

Data Extraction From Web Tables: The Devil Is In The Details, George Nagy, Sharad C. Seth, Dongpu Jin, David W. Embley, Spencer Machado, Mukkai Krishnamoorthy

CSE Conference and Workshop Papers

We present a method based on header paths for efficient and complete extraction of labeled data from tables meant for humans. Although many table configurations yield to the proposed syntactic analysis, some require access to semantic knowledge. Clicking on one or two critical cells per table, through a simple interface, is sufficient to resolve most of these problem tables. Header paths, a purely syntactic representation of visual tables, can be transformed (“factored”) into existing representations of structured data such as category trees, relational tables, and RDF triples. From a random sample of 200 web tables from ten large statistical web …

End-To-End Conversion Of Html Tables For Populating A Relational Database, George Nagy, David W. Embley, Sharad C. Seth

CSE Conference and Workshop Papers

Automating the conversion of human-readable HTML tables into machine-readable relational tables will enable end-user query processing of the millions of data tables found on the web. Theoretically sound and experimentally successful methods for index-based segmentation, extraction of category hierarchies, and construction of a canonical table suitable for direct input to a relational database are demonstrated on 200 heterogeneous web tables. The methods are scalable: the program generates the 198 Access compatible CSV files in ~0.1s per table (two tables could not be indexed).

Application-Aware Cognitive Multi-Hop Wireless Networking Testbed And Experiments, Trenton T. Evans

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

In this thesis, we present a new architecture for application-aware cognitive multihop wireless networks (AC-MWN) with testbed implementations and experiments. Cognitive radio is a technique to adaptively use the spectrum so that the resource can be used more efficiently in a low cost way. Multihop wireless networks can be deployed quickly and flexibly without a fixed infrastructure. In presented new architecture, we study backbone routing schemes with network cognition, routing scheme with network coding and spectrum adaptation. A testbed is implemented to test the schemes for AC-MWN. In addition to basic measurements, we implement a video streaming application based on …

Fiber-Optic Sensor For Strain-Insensitive Temperature Measurements, Ming Han

Department of Electrical and Computer Engineering: Faculty Publications

An in-line fiber-optic temperature sensor is disclosed. In an implementation, the in-line fiber-optic temperature sensor includes an optically transmissive fiber, a reflector, a microstructured fiber defining a channel therein for receiving a fluid, and a Fabry-Perot cavity in fluid communication with the micro structured fiber. The micro structured fiber can be retained between the optically transmissive fiber and the reflector. The Fabry-Perot cavity defined by a material and configured to receive a gas having an index of refraction that changes in a known way with temperature and pressure changes in fluid communication with the channel of the micro structured fiber. …

In Situ Electron Microscopy Of Plasmon-Mediated Nanocrystal Synthesis, Peter Sutter, Ying Li, Christos Argyropoulos, Eli A. Sutter

Department of Electrical and Computer Engineering: Faculty Publications

Chemical processes driven by nonthermal energy (e.g., visible light) are attractive for future approaches to energy conversion, synthesis, photocatalysis, and so forth. The growth of anisotropic metal nanostructures mediated by excitation of a localized surface plasmon resonance (LSPR) is a prototype example of such a reaction. Important aspects, notably the growth mechanism and a possible role of plasmonic “hot spots” within the metal nanostructures, remain poorly understood. Here, we use in situ electron microscopy to stimulate and image the plasmon-mediated growth of triangular Ag nanoprisms in solution. The quantification of the time-dependent evolution of the lateral size and thickness of …

Project Halon: Engaging Secondary Students In High-Altitude Balooning Experiments, James M. Taylor Jr, Derrick A. Nero

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Project HALON Overview

•Fewer US STEM graduates

•Shortage of STEM educators

•Lack of engaging, high quality STEM material in the classroom

•Potentially results in lower global economic competitiveness

Experiment Constraints

•Project brings together STEM major mentors and educators

•Builds understanding of research and operational challenges

•Students get excited about more complex experiments (CubeSATs)

HALON: High Altitude Learning Over Nebraska

•High altitude balloon lift platform

•Student-designed experiments tailored to student team abilities

•NASA-inspired near-space systems engineering process for tradeoffs

•Engagement / mentoring for pre-service and in-service educators

Physiologically-Aware Communication Architecture For Transmission Of Biomedical Signals In Basns For Emerging Iot Applications, Jose Santos, Dongming Peng, Hamid Sharif

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

This research work proposes a novel physiologicallyaware communication architecture for the transmission of biomedical signals in BASNs (Body Area Sensor Networks) and wearables for emerging IoT applications. The architecture to fulfill the following objectives:

• Reduce volume of biomedical data in IoT networks and Internet infrastructure.

• Minimize the required computational load of biomedical data on the cloud side.

• Extend the lifetime of the mobile wearable/BASN through improved energy savings.

This architecture is generalizable to class of biomedical signals. It prevents large volume of biomedical data to be generated; uses patient state to control almost any system parameter; achieves …

Reducing Graphene-Metal Contact Resistance Via Laser Nano-Welding, Kamran Keramatnejad, H. Rabiee Golgir, Y. S. Zhou, D. W. Li, X. Huang, Yongfeng Lu

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

The large graphene-metal contact resistance is a major limitation for development of graphene electronics. graphene behaves as an insulator for out-of-plane carrier transport to metallic contacts.

Laser nano-welding was developed and led to RC reductions of up to 84%.

Localized laser irradiation at the edges of graphene led to the formation of chemically active point defects.

Precise structural modifications and formation of G-M bonding led to improved carrier efficiency in graphene devices.

Ip Flow Mobility In The Industry: From An Economic Perspective, Jun Huang, Fang Fang, Cong-Cong Xing, Yi Qian

Department of Electrical and Computer Engineering: Faculty Publications

The popularity of social media together with the advancement of mobile Internet applications enabling the uploading of data plays a dominant role in the entire Internet traffic. IP flow mobility (IFOM) is proposed as an effective means to enhance the system capacity by offloading data from the cellular network to WiFi or Femtocells or other complementary networks. Although IFOM has been extensively investigated during the past few years, most of these studies, however, are concerned with IFOM technical issues only; little work regarding the IFOM application has been done from the service providers’ perspective. Unlike previous research, in this paper, …

Women In It: Be The Change, Marcia L. Dority Baker

Information Technology Services: Publications

The influence of established women in IT — specifically Florence Hudson and Melissa Woo — encouraged a librarian to apply for a position in Information Technology Services at the University of Nebraska–Lincoln.

A hands-on approach to planning the IT Leadership conference developed a strong collaborative network that also helped grow attendance.

Paying attention to the pros and cons of the 2016 conference guided the planners in modifying their approach to the upcoming October 2017 conference and its focus on diversity and inclusion.

A main goal for future IT Leadership conferences focusing on women and diversity in IT is providing attendees …

Specular Reflection Reduction By Metasurface Based On Parameteradjustable Meta-Atoms, Jianxun Su, Yao Lu, Hui Zhang, Zengrui Li, Yaoqing Lamar Yang ., Yongxing Che, Kainan Qi

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, an ultra-wideband, wide angle and polarization-insensitive metasurface is designed, fabricated, and characterized for suppressing the specular electromagnetic wave reflection or backward radar cross section (RCS). Square ring structure is chosen as the basic meta-atoms. A new physical mechanism based on size adjustment of the basic meta-atoms is proposed for ultra-wideband manipulation of electromagnetic (EM) waves. Based on hybrid array pattern synthesis (APS) and particle swarm optimization (PSO) algorithm, the selection and distribution of the basic meta-atoms are optimized simultaneously to obtain the ultra-wideband diffusion scattering patterns. The metasurface can achieve an excellent RCS reduction in an ultra-wide …

Ultra-Wideband, Wide Angle And Polarization-Insensitive Specular Reflection Reduction By Metasurface Based On Parameteradjustable Meta-Atoms, Jianxun Su, Yao Lu, Hui Zhang, Zengrui Li, Yaoqing Lamar Yang, Yongxing Che, Kainan Qi

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, an ultra-wideband, wide angle and polarization-insensitive metasurface is designed, fabricated, and characterized for suppressing the specular electromagnetic wave reflection or backward radar cross section (RCS). Square ring structure is chosen as the basic meta-atoms. A new physical mechanism based on size adjustment of the basic meta-atoms is proposed for ultra-wideband manipulation of electromagnetic (EM) waves. Based on hybrid array pattern synthesis (APS) and particle swarm optimization (PSO) algorithm, the selection and distribution of the basic meta-atoms are optimized simultaneously to obtain the ultra-wideband diffusion scattering patterns. The metasurface can achieve an excellent RCS reduction in an ultra-wide …

Rainbow Peacock Spiders Inspire Miniature Superiridescent Optics, Bor-Kai Hsiung, Radwanul Hasan Siddique, Doekele G. Stavenga, Jürgen C. Otto, Michael C. Allen, Ying Liu, Yongfeng Lu, Dimitri D. Deheyn, Matthew D. Shawkey, Todd A. Blackledge

Department of Electrical and Computer Engineering: Faculty Publications

Colour produced by wavelength-dependent light scattering is a key component of visual communication in nature and acts particularly strongly in visual signalling by structurallycoloured animals during courtship. Two miniature peacock spiders (Maratus robinsoni and M. chrysomelas) court females using tiny structured scales (~ 40 × 10 μm²) that reflect the full visual spectrum. Using TEM and optical modelling, we show that the spiders’ scales have 2D nanogratings on microscale 3D convex surfaces with at least twice the resolving power of a conventional 2D diffraction grating of the same period. Whereas the long optical path lengths required …

Controllable Plasmonic Nanostructures Induced By Dual-Wavelength Femtosecond Laser Irradiation, Weina Han, Lan Jiang, Xiaowei Li, Qingsong Wang, Shaojun Wang, Jie Hu, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

We demonstrated an abnormal double-peak (annular shaped) energy deposition through dualwavelength synthesis of the fundamental frequency (ω) and the second-harmonic frequency (2ω) of a femtosecond (fs) Ti:sapphire laser. The annular shaped distribution of the dual-wavelength fs laser was confirmed through real beam shape detection. This uniquely simple and flexible technique enables the formation of functional plasmonic nanostructures. We applied this double-peak fs-laser-induced dewetting effect to the controlled fabrication and precise deposition of Au nanostructures, by using a simple, lithography-free, and single-step process. In this process, the double-peak energy-shaped fs laser pulse induces surface patterning of a thin film followed by …

Preparation Of Monolayer Mos2 Quantum Dots Using Temporally Shaped Femtosecond Laser Ablation Of Bulk Mos2 Targets In Water, Bo Li, Lan Jiang, Xin Li, Peng Ran, Pei Zuo, Andong Wang, Liangti Qu, Yang Zhao, Zhihua Cheng, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

Zero-dimensional MoS₂ quantum dots (QDs) possess distinct physical and chemical properties, which have garnered them considerable attention and facilitates their use in a broad range of applications. In this study, we prepared monolayer MoS₂ QDs using temporally shaped femtosecond laser ablation of bulk MoS₂ targets in water. The morphology, crystal structures, chemical, and optical properties of the MoS₂ QDs were characterized by transmission electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, UV–vis absorption spectra, and photoluminescence spectra. The analysis results show that highly pure, uniform, and monolayer MoS₂ QDs can be successfully prepared. Moreover, …

High-Speed Adaptive Wireless Body Area Networks, Miftadi Sudjai, Le Chung Tran, Farzad Safaei, Tadeusz Wysocki, Son Lam Phung

Department of Electrical and Computer Engineering: Faculty Publications

Adaptive ultra-wideband wireless body area network (WBAN) is proposed in this paper as a feasible mobile health platform, offering a high-speed and robust service. It employs a space-time-frequency-coded (STFC) multiband orthogonal frequency division multiplexing ultra-wideband technology. It is designed to improve the average bit error performance for high data rate applications while maintaining a reasonably high throughput in body-to-external links of a WBAN. The proposed adaptive WBAN comprises two novel components, namely, the frame transmission model and the bit error rate (BER) estimation-based adaptive algorithm. In addition, the optimization of adaptive parameters is conducted to obtain an extra improvement, hence …

Identification And Characterization Of Irregular Consumptions Of Load Data, Desh Deepak Sharma, S. N. Singh, Jeremy Lin, Elham Foruzan

Department of Electrical and Computer Engineering: Faculty Publications

The historical information of loadings on substation helps in evaluation of size of photovoltaic (PV) generation and energy storages for peak shaving and distribution system upgrade deferral. A method, based on consumption data, is proposed to separate the unusual consumption and to form the clusters of similar regular consumption. The method does optimal partition of the load pattern data into core points and border points, high and less dense regions, respectively. The local outlier factor, which does not require fixed probability distribution of data and statistical measures, ranks the unusual consumptions on only the border points, which are a few …

Tunable Subnanometer Gap Plasmonic Metasurfaces, Dennis Doyle, Nicholas Charipar, Christos Argyropoulos, Scott A. Trammell, Rafaela Nita, Jawad Naciri, Alberto Piqué, Joseph B. Herzog, Jake Fontana

Department of Electrical and Computer Engineering: Faculty Publications

The index of refraction governs the flow of light through materials. At visible and near-infrared wavelengths the real part of the refractive index is limited to less than 3 for naturally occurring transparent materials, fundamentally restricting applications. Here, we carried out experiments to study the upper limit of the effective refractive index of self-assembled metasurfaces at visible and near-infrared wavelengths. The centimeter-scale metasurfaces were made of a hexagonally close packed (HCP) monolayer of gold nanospheres coated with tunable alkanethiol ligand shells, controlling the interparticle gap from 2.8 to 0.45 nm. In contrast to isolated dimer studies, the macroscale areas allow …

Flatland Plasmonics And Nanophotonics Based On Graphene And Beyond, Pai-Yen Chen, Christos Argyropoulos, Mohamed Farhat, J. Sebastian Gomez-Diaz

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, we review and discuss how the recently discovered two-dimensional (2D) Dirac materials, particularly graphene, may be utilized as new efficient platforms for excitations of propagating and localized surface plasmon polaritons (SPPs) in the terahertz (THz) and mid-infrared (MIR) regions. The surface plasmon modes supported by the metallic 2D materials exhibit tunable plasmon resonances that are essential, yet missing, ingredients needed for THz and MIR photonic and optoelectronic devices. We describe how the atomically thin graphene monolayer and metamaterial structures based on it may tailor and control the spectral, spatial, and temporal properties of electromagnetic radiation. In the …

Decreased Home Cage Movement And Oromotor Impairments In Adult Fmr1-Ko Mice, Stephen J. Bonasera, Tammy R. Chaudoin, Evan H. Goulding, Mateusz Mittek, Anna Dunaevsky

Department of Electrical and Computer Engineering: Faculty Publications

Fragile X syndrome (FXS) is a common inherited disorder that significantly impacts family and patient day-to-day living across the entire lifespan. The childhood and adolescent behavioral consequences of FXS are well-appreciated. However, there are significantly fewer studies (except those examining psychiatric comorbidities) assessing behavioral phenotypes seen in adults with FXS. Mice engineered with a genetic lesion of Fmr1 recapitulate important molecular and neuroanatomical characteristics of FXS, and provide a means to evaluate adult behavioral phenotypes associated with FXS. We give the first description of baseline behaviors including feeding, drinking, movement, and their circadian rhythms; all observed over 16 consecutive days …

Higher C-Reactive Protein Levels Predict Postoperative Delirium In Older Patients Undergoing Major Elective Surgery: A Longitudinal Nested Case-Control Study, Simon T. Dillon, Sarinnapha M. Vasunilashorn, Long Ngo, Hasan H. Otu, Sharon K. Inouye, Richard N. Jones, David C. Alsop, George A. Kuchel, Eran D. Metzger, Steven E. Arnold, Edward R. Marcantonio, Towia A. Libermann

Department of Electrical and Computer Engineering: Faculty Publications

Background—Delirium is a common, morbid, and costly postoperative complication.. We aimed to identify blood-based postoperative delirium markers in a nested case control study of older surgical patients using a proteomics approach followed by enzyme-linked immunosorbent assay (ELISA) validation.

Methods and Materials—The Successful Aging after Elective Surgery Study enrolled dementia-free adults age ≥70 undergoing major scheduled non-cardiac surgery (N=566; 24% delirium). Plasma was collected at 4 timepoints: preoperatively (PREOP), post-anesthesia care unit (PACU), postoperative day 2 (POD2) and 1 month follow-up (PO1MO). Matched pairs were selected for the independent discovery (39 pairs) and replication cohorts (36 pairs), which were …

Correction: Genomic Counter-Stress Changes Induced By The Relaxation Response, Jeffery A. Dusek, Hasan H. Otu, Ann L. Wohlhueter, Manoj Bhasin, Luiz F. Zerbini, Marie G. Joseph, Herbert Benson, Towia A. Libermann

Department of Electrical and Computer Engineering: Faculty Publications

The Competing Interests statement is incorrect. The correct Competing Interests statement is: The following authors hold or have held positions at the Benson-Henry Institute for Mind Body Medicine at Massachusetts General Hospital, which is paid by patients and their insurers for running the SMART-3RP and related relaxation/mindfulness clinical programs, markets related products such as books, DVDs, CDs and the like, and holds a patent pending (PCT/ US2012/049539 filed August 3, 2012) entitled "Quantitative Genomics of the Relaxation Response": JAD, ALW, HB.

Formation Of Aggregated Nanoparticle Spheres Through Femtosecond Laser Surface Processing, Alfred T. Tsubaki, Mark A. Koten, Michael J. Lucis, Craig Zuhlke, Natale J. Ianno, Jeffrey E. Shield, Dennis R. Alexander

Department of Electrical and Computer Engineering: Faculty Publications

A detailed structural and chemical analysis of a class of self-organized surface structures, termed aggregated nanoparticle spheres (AN-spheres), created using femtosecond laser surface processing (FLSP) on silicon, silicon carbide, and aluminum is reported in this paper. AN-spheres are spherical microstructures that are 20–100 μm in diameter and are composed entirely of nanoparticles produced during femtosecond laser ablation of material. AN-spheres have an onion-like layered morphology resulting from the build-up of nanoparticle layers over multiple passes of the laser beam. The material properties and chemical composition of the AN-spheres are presented in this paper based on scanning electron microscopy (SEM), focused …

Real-Time Pricing Strategy Based On The Stability Of Smart Grid For Green Internet Of Things, Huwei Chen, Hui Hui, Zhou Su, Dongfeng Fang, Yilong Hui

Department of Electrical and Computer Engineering: Faculty Publications

The ever increasing demand of energy efficiency and the strong awareness of environment have led to the enhanced interests in green Internet of things (IoTs). How to efficiently deliver power, especially, with the smart grid based on the stability of network becomes a challenge for green IoTs. Therefore, in this paper we present a novel real-time pricing strategy based on the network stability in the green IoTs enabled smart grid. Firstly, the outage is analyzed by considering the imbalance of power supply and demand as well as the load uncertainty. Secondly, the problem of power supply with multiple-retailers is formulated …

Shielding Effectiveness Performance Of Conductive Concrete Structures, Lim Nguyen, Aaron Krause, Christopher Tuan, Joel D. Blasey, Holly Mcnerney, Ferdinand J. Metzger

Department of Electrical and Computer Engineering: Faculty Publications

Conductive concrete mixtures have been designed and demonstrated to perform electromagnetic shielding. This paper describes the design, testing methods, and results obtained from the development of conductive concrete construction for structured electromagnetic shielding.