Digital Commons Network^™

Use Of Environmental Scanning Electron Microscopy For In Situ Observation Of Interaction Of Cells With Micro- And Nanoprobes, Alexander Goponenko, B. J. Boyle, K. I. Jahan, Maxim V. Gerashchenko, Dmitri E. Fomenko, Vadim N. Gladyshev, Yuris A. Dzenis

Department of Mechanical and Materials Engineering: Faculty Publications

Precision intracellular sensing, probing and manipulation offer unprecedented opportunities for advances in biological sciences. Next-generation ultra-fine probes will be capable of targeting individual cell organelles. Development of such probes as well as probes capable of penetrating through tough cell walls requires detailed knowledge of cell-probe interaction. This Letter evaluated the applicability of environmental scanning electron microscopy (ESEM) for cell and cell-probe interaction imaging. Several types of cells (plant and yeast cells as well as mouse spermatozoa) were successfully imaged in their natural state, with mouse spermatozoa observed by ESEM for the first time. Computerized stage applied to image was tough …

Achieving High Efficiency Laminated Polymer Solar Cell With Interfacial Modified Metallic Electrode And Pressure Induced Crystallization, Yongbo Yuan, Yu Bi, Jinsong Huang

Department of Mechanical and Materials Engineering: Faculty Publications

We report efficient laminated organic photovoltaic device with efficiency approach the optimized device by regular method based on Poly(3-hexylthiophene-2,5-diyl) and [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM). The high efficiency is mainly attributed to the formation of a concrete polymer/metal interface mechanically and electrically by the use of electronic-glue, and using the highly conductive and flexible silver film as anode to reduce photovoltage loss and modifying its work function for efficiency hole extraction by ultraviolet/ozone treatment, and the pressure induced crystallization of PCBM.

"Introduction" To "Symposium: The Fate Of Anglo-American Capitalism", Sandra J. Peart

Jepson School of Leadership Studies articles, book chapters and other publications

The call for papers in this special issue asked whether there is a future for the robust sort of capitalism favoured by Adam Smith or whether we have reached a limit to Anglo-American capitalism as the engine of human betterment. Contemporary events loomed large late in 2008 and it seemed appropriate to consider whether Anglo-American capitalism was passing away. We were particularly interested in contributions that viewed current economic events through a lens informed by Smith's teaching on institutions, money and economic growth.

Priority Preemption For Real-Time Application Qos Guarantees In Cooperative Vehicular Networks, Ting Zhou, Hamid Sharif, Michael Hempel, Puttipong Mahasukhon, Tao Ma, Pradhumna Shrestha

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

Inter-vehicle and roadside-to-vehicle communications can contribute to a safer and more efficient driving experience by providing time-sensitive and location-aware information. However, its performance suffers from vehicle mobility, intermittent user connectivity, and wireless channel unreliability. In this paper, we propose a novel cross-layer optimization approach based on our Adaptive Distributed Cooperative Medium Access Control (ADC-MAC) protocol to guarantee the quality-of-service (QoS) of real-time applications. Markov chain based theoretical analysis show that our proposed priority preemption approach can improve the quality of a real-time application by guaranteeing its bandwidth and reducing its transmission latency.

Prof. Dr. Marek E. Bialkowski (1951 – 2011), Tadeusz Wysocki, Salman Durrani, Rodney A. Kennedy

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

It is our sad duty to report the untimely death of Prof. Dr. Marek E. Bialkowski, who passed away on Thursday, October 27, 2011 after a short unexpected illness caused by pneumonia. He was a remarkable researcher and a mentor and friend to many us and he will be greatly missed.

Marek was born in Sochaczew, Poland, in 1951. He received the M.Eng.Sc. degree in applied mathematics and the Ph.D. degree in electrical engineering, both from the Warsaw University of Technology, Warsaw, Poland, in 1974 and 1979, respectively. He received the Doctor of Engineering (higher doctorate) degree in computer science …

Impact Of Channel Estimation Errors On Effectiveness Of Eigenvector-Based Jamming For Physical Layer Security In Wireless Networks, James M. Taylor, Michael Hempel, Hamid Sharif, Shichuan Ma, Yaoqing Lamar Yang

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

In this paper, we present our study of an Eigenvector-based artificial noise-based jamming technique developed to provide increased wireless physical layer security in transmit-receive diversity systems and analyze the impact of channel estimation errors on system performance. Our simulation results showed that with knowledge of perfect channel state information, the technique provided secrecy capacity of approximately 7 bits/s/Hz for a normalized transmit power of 25 dB for a variety of transmit, receive, and eavesdropper configurations. We also describe a novel method to simulate generalized channel state information estimation errors. While other publications neglect the impact of these estimation errors, our …

Timing Accuracy Of Self-Encoded Spread Spectrum Navigation With Communication, Won Mee Jang

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

The author presents the timing accuracy of self-encoded spread spectrum (SESS) in navigation. SESS eliminates the need for traditional transmit and receive pseudo noise code generators. As the term implies, the spreading code is instead obtained from the random digital information source itself. SESS was shown to improve system performance significantly in fading channels. In this study, the authors investigate the timing accuracy of SESS in comparison to m-sequence and Gold code. SESS can be an excellent candidate for navigation with communication.

A Degree Of Conflict Model For Workspace Awareness, Bakhtiar Khan Kasi, Anita Sarma

School of Computing: Technical Reports

Workspace awareness solutions provide ongoing change information at the level of files. This makes the user responsible for identifying how current changes affect their tasks and provides no guidance for planning their (future) tasks. Here, we present our approach to task-based awareness that calculates a degree-of-conflict for tasks and recommends an optimum set of tasks that minimizes the risk of conflicts. Specifically, we present three novel research ideas: (1) transition from the current file-based awareness systems to task-based awareness, (2) transition from reactive conflict detection to proactive conflict prediction, and (3) a degree-of-conflict model that models conflicts per task per …

Rightsizing Bundle Link Capacities For Energy Savings In The Core Network, Lin Liu, Byrav Ramamurthy

School of Computing: Technical Reports

Current core networks are composed of high-end routers which are connected by high-speed fibers. These optical connections are commonly overprovisioned and in low utilization. Many of them are combined together to form bundle links or composite links and the component links are referred to as sublinks. These physical sublinks could be SONET connections, Ethernet circuits, wavelengths on a fiber, etc and they could be shut down or brought up independently. Selectively shutting down sublinks during low traffic periods could save a large amount of energy while keeping the network topology unchanged. Based on this concept, we propose a local heuristical …

Location Cheating: A Security Challenge To Location-Based Social Network Services, Mai Ren

School of Computing: Technical Reports

Location-based mobile social network services such as Foursquare and Gowalla have grown exponentially over the past several years. These location-based services utilize the geographical position to enrich user experiences in a variety of contexts, including location-based searching and location-based mobile advertising. To attract more users, the location-based mobile social network services provide real-world rewards to the user, when a user checks in at a certain venue or location. This gives incentives for users to cheat on their locations.

Machine Learning With Incomplete Information, Yaling Zheng

School of Computing: Technical Reports

Machine learning algorithms detects patterns, regularities, and rules from the training data and adjust program actions accordingly. For example, when a learner (a computer program) sees a set of patient cases (patient records) with corresponding diagnoses, it can predict the presence of a disease for future patients. A somewhat unrealistic assumption in typical machine learning applications is that data is freely available. In my dissertation, I will present our research efforts to mitigate this assumption in the areas of active machine learning and budgeted machine learning.

Relational Neighborhood Inverse Consistency For Constraint Satisfaction: A Structure-Based Approach For Adjusting Consistency & Managing Propagation, Robert J. Woodward

School of Computing: Technical Reports

Freuder and Elfe [1996] introduced Neighborhood Inverse Consistency (NIC) as a local consistency property defined on the values in the variables’ domains of a Constraint Satisfaction Problem (CSP). Debruyne and Bessiere [2001] showed that enforcing NIC on binary CSPs is ineffective on sparse graph and too costly on dense graphs. In this thesis, we propose Relational Neighborhood Inverse Consistency (RNIC), an extension of NIC defined as a local consistency property on the tuples of the relations of a CSP. We characterize RNIC for both binary and non-binary CSPs, and propose an algorithm for enforcing it whose complexity is bounded by …

Reformulating R(*;M)C With Tree Decomposition, Shant Karakashian, Robert J. Woodward, Berthe Y. Choueiry

School of Computing: Conference and Workshop Papers

Local consistency properties and algorithms for enforcing them are central to the success of Constraint Processing. Recently, we have demonstrated the importance of higher levels of consistency and the effectiveness of their algorithms for solving difficult problems (Karakashian et al. 2010; Woodward et al. 2011). In this paper, we introduce two reformulation techniques for improving the effectiveness of our algorithm for the relational consistency property R(*;m)C (Karakashian et al. 2010). Both techniques exploit a tree decomposition of the constraint network of a Constraint Satisfaction Problem (CSP), which is a tree embedding of the network. Our first reformulation technique …

Feature Interaction Faults Revisited: An Exploratory Study, Brady J. Garvin, Myra B. Cohen

School of Computing: Conference and Workshop Papers

While a large body of research is dedicated to testing for feature interactions in configurable software, there has been little work that examines what constitutes such a fault at the code level. In consequence, we do not know how prevalent real interaction faults are in practice, what a typical interaction fault looks like in code, how to seed interaction faults, or whether current interaction testing techniques are effective at finding the faults they aim to detect.

We make a first step in this direction, by deriving a white box criterion for an interaction fault. Armed with this criterion, we perform …

A Dynamic Local Method For Bandwidth Adaptation In Bundle Links To Conserve Energy In Core Networks, Lin Liu, Byrav Ramamurthy

School of Computing: Conference and Workshop Papers

Energy savings in bundle links of the core network has been investigated recently. The bundle link technique is widely used in current core networks to provide higher bandwidth and more resilience. Basically a bundle link is composed of several high-speed physical sublinks which could be SONET connections, Ethernet circuits, etc. in order to make them work together as a virtual connection. In current network operations, all of the sublinks are activated if the bundle link is powered on although the sublinks could be shut down or brought up independently. Smartly and dynamically shutting down and bringing up sublinks and their …

Directed Test Suite Augmentation, Zhihong Xu

School of Computing: Conference and Workshop Papers

Test suite augmentation techniques are used in regression testing to identify code elements affected by changes and to generate test cases to cover those elements. Whereas methods and techniques to find affected elements have been extensively researched in regression testing, how to generate new test cases to cover these elements cost-effectively has rarely been studied. It is known that generating test cases is very expensive, so we want to focus on this second step. We believe that reusing existing test cases will help us achieve this task. This research intends to provide a framework for test suite augmentation techniques that …

Tcp Congestion Avoidance Algorithm Identification, Peng Yang, Wen Luo, Lisong Xu, Jitender S. Deogun, Ying Lu

School of Computing: Conference and Workshop Papers

The Internet has recently been evolving from homogeneous congestion control to heterogeneous congestion control. Several years ago, Internet traffic was mainly controlled by the traditional AIMD algorithm, whereas Internet traffic is now controlled by many different TCP algorithms, such as AIMD, BIC, CUBIC, and CTCP. However, there is very little work on the performance and stability study of the Internet with heterogeneous congestion control. One fundamental reason is the lack of the deployment information of different TCP algorithms. In this paper, we first propose a tool called TCP Congestion Avoidance Algorithm Identification (CAAI) for actively identifying the TCP algorithm of …

Using Property-Based Oracles When Testing Embedded System Applications, Tingting Yu, Ahyoung Sung, Witawas Srisaan, Gregg Rothermel

School of Computing: Conference and Workshop Papers

Embedded systems are becoming increasingly ubiquitous, controlling a wide variety of popular and safety critical devices. Effective testing techniques could improve the dependability of these systems. In prior work we presented an approach for testing embedded systems, focusing on embedded system applications and the tasks that comprise them. In this work we focus on a second but equally important aspect of testing embedded systems; namely, the need to provide observability of system behavior sufficient to allow engineers to detect failures. We present several property-based oracles that can be instantiated in embedded systems through program analysis and instrumentation, and can detect …

Automatic Generation Of Load Tests, Pingyu Zhang, Sebastian Elbaum, Matthew Dwyer

School of Computing: Conference and Workshop Papers

Load tests aim to validate whether system performance is acceptable under peak conditions. Existing test generation techniques induce load by increasing the size or rate of the input. Ignoring the particular input values, however, may lead to test suites that grossly mischaracterize a system’s performance. To address this limitation we introduce a mixed symbolic execution based approach that is unique in how it 1) favors program paths associated with a performance measure of interest, 2) operates in an iterative-deepening beam-search fashion to discard paths that are unlikely to lead to high-load tests, and 3) generates a test suite of a …

Response Time Analysis Of Hierarchical Scheduling: The Synchronized Deferrable Servers Approach, Haitao Zhu, Steve Goddard, M. Dwyer

School of Computing: Conference and Workshop Papers

Hierarchical scheduling allows reservation of processor bandwidth and the use of different schedulers for different applications on a single platform. We propose a hierarchical scheduling interface called synchronized deferrable servers that can reserve different processor bandwidth on each core, and can combine global and partitioned scheduling on a multicore platform. Significant challenges will arise in the response time analysis of a task set if the tasks are globally scheduled on a multiprocessor platform and the processor bandwidth reserved for the tasks on each processor is different; as a result, existing works on response time analysis for dedicated scheduling on identical …

Experiences With Dynamic Circuit Creation In A Regional Network Testbed, Pragatheeswaran Angu, Byrav Ramamurthy

School of Computing: Conference and Workshop Papers

In this paper we share our experiences of enabling dynamic circuit creation in the GpENI network. GpENI is a network research testbed in the mid-west USA involving several educational institutions. University of Nebraska-Lincoln is involved in provisioning dynamic circuits across the GpENI network among its participating universities. We discuss several options investigated for deploying dynamic circuits over the GpENI network as well as our demonstration experiments at the GENI engineering conferences. UNL has also collaborated with ProtoGENI project of University of Utah and Mid-Atlantic Crossroads (MAX) facility of Washington DC to create interdomain dynamic circuits.

End-User Programmers And Their Communities: An Artifact-Based Analysis, Kathryn T. Stolee, Sebastian Elbaum, Anita Sarma

School of Computing: Conference and Workshop Papers

End-user programmers outnumber professionals programmers, write software that matters to an increasingly large number of users, and face software engineering challenges that are similar to their professionals counterparts. Yet, we know little about how these end-user programmers create and share artifacts as part of a community. To gain a better understanding of these issues, we perform an artifact-based community analysis of 32,000 mashups from the Yahoo! Pipes repository. We observed that, like with other online communities, there is great deal of attrition but authors that persevere tend to improve over time, creating pipes that are more configurable, diverse, complex, and …

History Repeats Itself More Easily When You Log It: Versioning For Mashups, Sandeep Kaur Kuttal, Anita Sarma, Gregg Rothermel

School of Computing: Conference and Workshop Papers

Web mashup environments provide a way for users to combine data from web applications and services to create new content. Currently, these environments do not provide support for tracking the development histories of mashups. We have thus added configuration management support to the Yahoo! Pipes mashup environment. We describe this support, and provide results of an experiment studying the ability of programmers to create and debug mashups in its presence. Our results show that versioning support can help both groups of users do both tasks better.

Probabilistic Risk Assessment For Security Requirements: A Preliminary Study, Seok-Won Lee

School of Computing: Conference and Workshop Papers

Risk assessment is a critical decision making process during the Security Certification and Accreditation (C&A) process. However, existing infrastructure-wide C&A processes in real world are challenged by the ever increasing complexity of information systems and their diverse socio-technical operational environments. The lack of an explicit model and the associated uncertainties of software behavior are two main reasons that directly impact the effectiveness of risk assessment as well as the subjective decisions made based on the different level of domain expertise. In this paper, we propose a method for a probabilistic model driven risk assessment on security requirements. The security requirements …

A Hybrid Directed Test Suite Augmentation Technique, Zhihong Xu, Yunho Kim, Moonzoo Kim, Gregg Rothermel

School of Computing: Conference and Workshop Papers

Test suite augmentation techniques are used in regression testing to identify code elements affected by changes and to generate test cases to cover those elements. In previous work, we studied two approaches to augmentation, one using a concolic test case generation algorithm and one using a genetic test case generation algorithm. We found that these two approaches behaved quite differently in terms of their costs and their abilities to generate effective test cases for evolving programs. In this paper, we present a hybrid test suite augmentation technique that combines these two test case generation algorithms. We report the results of …

Limited Scope Permitting For Time-Sensitive Project Delivery Systems, Wayne Jensen, Bruce Fischer, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Delivery of construction projects in the United States has traditionally been based upon the design-bid-build system. TIlis system has been used to create numerous impressive structures, but it often proves expensive and usually requires considerable time, because design, permitting and construction are accomplished in sequential order and do not overlap. Several alternatives to the traditional system have been developed, many of which fall under the classification of time-sensitive project delivery systems. The most commonly used time-sensitive project delivery systems are phased and fast-track construction (FaZio, Moselhi, Theberge & Revay 1988a). Figure 1 illustrates some of the major differences between traditional …

A Building Lca Case Study Using Autodesk Ecotect And Bim Model, Endong Wang, Zhigang Shen, Charles Barryman

Department of Construction Engineering and Management: Faculty Publications

The main objective of this study is to evaluate the potential of utilizing building information model (BIM) to perform whole building Life Cycle Analysis (LCA). The research question addressed was how life cycle performance of a building was affected quantitatively by design configurations. Life cycle energy consumption and CO₂ emission of a university building in the Midwest was calculated using Autodesk® Ecotect and BIM model. The study compared life cycle performance, i.e., CO₂ emissions and energy consumptions, among different design configurations, as well as their distributions in the stages of the building’s life time. Sensitivity analysis was performed …

Socializing Messages In Blue-Collar Families: Communicative Pathways To Social Mobility And Reproduction, Kristen Lucas

Department of Communication Studies: Faculty Publications

This study explicitly links processes of anticipatory socialization to social mobility and reproduction. An examination of the socializing messages exchanged between blue-collar parents (n=41) and their children (n=25) demonstrate that family-based messages about work and career seldom occur in straightforward, unambiguous ways. Instead, messages take several paths (direct, indirect, ambient, and omission). Further, the content of messages communicated along these paths often is contradictory. That is, sons and daughters receive messages that both encourage and discourage social mobility. Ultimately, these individuals must negotiate the meanings of family-based anticipatory socialization communicated to them through a mix of messages.

Power Controlled Multirate Multimedia Transmission In Self-Encoded Spread Spectrum Over Dynamic Fading Channels, Liang Chi, Poomathi Duraisamy, Won Mee Jang, Lim Nguyen

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

In this paper, we propose to apply power control to self-encoded spread spectrum (SESS) in multirate and multimedia applications. The transmitter employs power control to to combat dynamic channel fading and the receiver employs decorrelation to reduce interference from multiple applications. We show that iterative detection can significantly improve the system performance. The proposed approach also improves the power efficiency which is essential in battery-driven communications such as mobile cellular systems.

Self-Encoded Spread Spectrum For Multirate Multimedia Communication In Multipath Channel, Liang Chi, Won Mee Jang, Lim Nguyen

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

In this paper, we propose the self-encoded spread spectrum (SESS) with multirate multimedia communication in multipath channel. In multirate multimedia SESS system, each application has their own transmission bit rate. The signal is transmitted through multipath channels each with different channel gain and time delay. We view the main path as the signal resource and other paths as interference. At the receiver side, decorrelation scheme is employed for the main path combined signal not only to reduce the crosstalk between different applications, but also to provide a better estimation for the despreading sequence in the main path. Interference cancellation(IC) in …