Computer Engineering Commons^™

Monitoring Dbms Activity To Detect Insider Threat Using Query Selectivity, Prajwal B. Hegde

Open Access Theses

The objective of the research presented in this thesis is to evaluate the importance of query selectivity for monitoring DBMS activity and detect insider threat. We propose query selectivity as an additional component to an existing anomaly detection system (ADS). We first look at the advantages of working with this particular ADS. This is followed by a discussion about some existing limitations in the anomaly detection system (ADS) and how it affects its overall performance. We look at what query selectivity is and how it can help improve upon the existing limitations of the ADS. The system is then implemented …

Interactive Logical Analysis Of Planning Domains, Rajesh Kalyanam

Open Access Dissertations

Humans exhibit a significant ability to answer a wide range of questions about previously unencountered planning domains, and leverage this ability to construct “general-purpose'' solution plans for the domain.

The long term vision of this research is to automate this ability, constructing a system that utilizes reasoning to automatically verify claims about a planning domain. The system would use this ability to automatically construct and verify a generalized plan to solve any planning problem in the domain. The goal of this thesis is to start with baseline results from the interactive verification of claims about planning domains and develop the …

Three Dimensional Moving Pictures With A Single Imager And Microfluidic Lens, Chao Liu

Open Access Dissertations

Three-dimensional movie acquisition and corresponding depth data is commonly generated from multiple cameras and multiple views. This technology has high cost and large size which are limitations for medical devices, military surveillance and current consumer products such as small camcorders and cell phone movie cameras. This research result shows that a single imager, equipped with a fast-focus microfluidic lens, produces a highly accurate depth map. On test material, the depth is found to be an average Root Mean Squared Error (RMSE) of 3.543 gray level steps (1.38\%) accuracy compared to ranging data. The depth is inferred using a new Extended …

Exploring Spin-Transfer-Torque Devices And Memristors For Logic And Memory Applications, Zoha Pajouhi

Open Access Dissertations

As scaling CMOS devices is approaching its physical limits, researchers have begun exploring newer devices and architectures to replace CMOS.

Due to their non-volatility and high density, Spin Transfer Torque (STT) devices are among the most prominent candidates for logic and memory applications. In this research, we first considered a new logic style called All Spin Logic (ASL). Despite its advantages, ASL consumes a large amount of static power; thus, several optimizations can be performed to address this issue. We developed a systematic methodology to perform the optimizations to ensure stable operation of ASL.

Second, we investigated reliable design of …

A Holistic Approach To Lowering Latency In Geo-Distributed Web Applications, Shankaranarayanan Puzhavakath Narayanan

Open Access Dissertations

User perceived end-to-end latency of web applications have a huge impact on the revenue for many businesses. The end-to-end latency of web applications is impacted by: (i) User to Application server (front-end) latency which includes downloading and parsing web pages, retrieving further objects requested by javascript executions; and (ii) Application and storage server(back-end) latency which includes retrieving meta-data required for an initial rendering, and subsequent content based on user actions.

Improving the user-perceived performance of web applications is challenging, given their complex operating environments involving user-facing web servers, content distribution network (CDN) servers, multi-tiered application servers, and storage servers. Further, …

Improving The Resilience Of Cyber-Physical Systems Under Strategic Adversaries, Paul Wood

Open Access Dissertations

Renewable energy resources challenge traditional energy system operations by substituting the stability and predictability of fossil fuel based generation with the unreliability and uncertainty of wind and solar power. Rising demand for green energy drives grid operators to integrate sensors, smart meters, and distributed control to compensate for this uncertainty and improve the operational efficiency of the grid. Real-time negotiations enable producers and consumers to adjust power loads during shortage periods, such as an unexpected outage or weather event, and to adapt to time-varying energy needs. While such systems improve grid performance, practical implementation challenges can derail the operation of …

Design And Implementation Of Benes/Clos On-Chip Interconnection Networks, Yikun Jiang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Networks-on-Chip (NoCs) have emerged as the key on-chip communication architecture for multiprocessor systems-on-chip and chip multiprocessors. Single-hop non-blocking networks have the advantage of providing uniform latency and throughput, which is important for cachecoherent NoC systems. Existing work shows that Benes networks have much lower transistor count and smaller circuit area but longer delay than crossbars. To reduce the delay, we propose to design the Clos network built with larger size switches. Using less than half number of stages than the Benes network, the Clos network with 4x4 switches can significantly reduce the delay. This dissertation focuses on designing high performance …

Design, Fabrication And Testing Of Monolithic Low-Power Passive Sigma-Delta Analog-To-Digital Converters, Angsuman Roy

UNLV Theses, Dissertations, Professional Papers, and Capstones

Analog-to-digital converters are critically important in electronic systems. The

difficulty in meeting high performance parameters increases as integrated circuit design

process technologies advance into the deep nanometer region. Sigma-delta analog-todigital

converters are an attractive option to fulfill many data converter requirements.

These data converters offer high performance while relaxing requirements on the precision

of components within an integrated circuit. Despite this, the active integrators found within

sigma-delta analog-to-digital converters present two main challenges. These challenges are

the power consumption of the active amplifier and achieving gain-bandwidth necessary for

sigma-delta data converters in deep nanometer process technologies. Both of these

challenges …

Learning In The Real World: Constraints On Cost, Space, And Privacy, Matt J. Kusner

McKelvey School of Engineering Graduate Student Theses & Dissertations

The sheer demand for machine learning in fields as varied as: healthcare, web-search ranking, factory automation, collision prediction, spam filtering, and many others, frequently outpaces the intended use-case of machine learning models. In fact, a growing number of companies hire machine learning researchers to rectify this very problem: to tailor and/or design new state-of-the-art models to the setting at hand.

However, we can generalize a large set of the machine learning problems encountered in practical settings into three categories: cost, space, and privacy. The first category (cost) considers problems that need to balance the accuracy of a machine learning model …

Optimizing Virtual Resource Management In Cloud Datacenters, Liuhua Chen

All Dissertations

Datacenter clouds (e.g., Microsoft's Azure, Google's App Engine, and Amazon's EC2) are emerging as a popular infrastructure for computing and storage due to their high scalability and elasticity. More and more companies and organizations shift their services (e.g., online social networks, Dropbox file hosting) to clouds to avoid large capital expenditures. Cloud systems employ virtualization technology to provide resources in physical machines (PMs) in the form of virtual machines (VMs). Users create VMs deployed on the cloud and each VM consumes resources (e.g., CPU, memory and bandwidth) from its host PM. Cloud providers supply services by signing Service Level Agreement …

Variable Response Of A Thermally Tuned Mems Pressure Sensor, Robert A. Lake, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

A typical microelectromechanical systems (MEMS) pressure sensor consists of a thin, deformable membrane and sensing element such as a piezoresistive element which is used to measure the amount of deflection in response to an applied pressure. Previous efforts demonstrated that buckled membranes, from silicon on insulator (SOI) wafers, can be thermally tuned via joule heating. By applying heat to the membrane through a resistive heating element, compressive stress is induced in the membrane causing it to buckle further out of plane and increasing its overall stiffness response. It is demonstrated that by increasing the stiffness of the membrane, the response …

Cufa: A More Formal Definition For Digital Forensic Artifacts, Vikram S. Harichandran, Daniel Walnycky, Ibrahim Baggili, Frank Breitinger

Electrical & Computer Engineering and Computer Science Faculty Publications

The term “artifact” currently does not have a formal definition within the domain of cyber/ digital forensics, resulting in a lack of standardized reporting, linguistic understanding between professionals, and efficiency. In this paper we propose a new definition based on a survey we conducted, literature usage, prior definitions of the word itself, and similarities with archival science. This definition includes required fields that all artifacts must have and encompasses the notion of curation. Thus, we propose using a new term e curated forensic artifact (CuFA) e to address items which have been cleared for entry into a CuFA database (one …

Deleting Collected Digital Evidence By Exploiting A Widely Adopted Hardware Write Blocker, Christopher S. Meffert, Ibrahim Baggili, Frank Breitinger

Electrical & Computer Engineering and Computer Science Faculty Publications

In this primary work we call for the importance of integrating security testing into the process of testing digital forensic tools. We postulate that digital forensic tools are increasing in features (such as network imaging), becoming networkable, and are being proposed as forensic cloud services. This raises the need for testing the security of these tools, especially since digital evidence integrity is of paramount importance. At the time of conducting this work, little to no published anti-forensic research had focused on attacks against the forensic tools/process.We used the TD3, a popular, validated, touch screen disk duplicator and hardware write blocker …

Use Of Clustering Techniques For Protein Domain Analysis, Eric Rodene

School of Computing: Dissertations, Theses, and Student Research

Next-generation sequencing has allowed many new protein sequences to be identified. However, this expansion of sequence data limits the ability to determine the structure and function of most of these newly-identified proteins. Inferring the function and relationships between proteins is possible with traditional alignment-based phylogeny. However, this requires at least one shared subsequence. Without such a subsequence, no meaningful alignments between the protein sequences are possible. The entire protein set (or proteome) of an organism contains many unrelated proteins. At this level, the necessary similarity does not occur. Therefore, an alternative method of understanding relationships within diverse sets of proteins …

Engineered Surfaces To Control Secondary Electron Emission For Multipactor Suppression, James M. Sattler, Ronald A. Coutu Jr., Robert A. Lake, Tod V. Laurvick

Electrical and Computer Engineering Faculty Research and Publications

A significant problem for space-based systems is multipactor - an avalanche of electrons caused by repeated secondary electron emission (SEE). The consequences of multipactor range from altering the operation of radio frequency (RF) devices to permanent device damage. Existing efforts to suppress multipactor rely heavily on limiting power levels below a multipactor threshold [1]. This research applies surface micromachining techniques to create porous surfaces to control the secondary electron yield (SEY) of a material for multipactor suppression. Surface characteristics of interest include pore aspect ratio and density. A discussion is provided on the advantage of using electroplating (vice etching) to …

Design Of Ferroelectric Mems Energy Harvesting Devices, Noah T. Blach, Robert A. Lake, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

Waste heat is a widely available but little used source of power. Converting a thermal gradient into electricity is conventionally done using the Seebeck effect, but devices that use this effect are naturally inefficient. An alternate approach uses microelectromechanical systems (MEMS) to generate movement and time-varying temperature from a constant temperature gradient. Ferroelectric materials can harvest electricity from moving structures and temperature variations. This concept was realized using traditional silicon microprocessing techniques. A silicon on insulator (SOI) wafer was backside Deep Reactive Ion Etched (DRIE) to form a one mm² by 7 micron thick silicon/silicon dioxide membrane. Lead zirconate …

Enhancing The Thermal Performance Of Temporary Fabric Structures For The Advanced Energy Efficient Shelter System, Justin E. Eshleman, Robert A. Lake, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

The focus of this research is to characterize the thermal load on temporary fabric shelters deployed in the Middle East in order to establish realistic contract specification for the thermal performance of future shelters. Three different testing methods were utilized to evaluate shelter thermal performance. Small-scale tests allowed for economical comparisons of different shelter materials and configurations.

Standardized Testing Of Non-Standard Photovoltaic Pavement Surfaces, John H. Nussbaum, Robert A. Lake, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

Emerging photovoltaic products have expanded the applications for the technologies into markets previously unconsidered for what was thought to be a delicate electronic product. One company leading this effort, Solar Roadways, Incorporated, is producing pavement replacing photovoltaic systems and proposing their use in everything from sidewalks to runways. Current pavement testing methods cannot be applied to these non-homogenous structures to identify if they can support the required loads. However, the standards called out specifically for pavements may be able to be translated to these products and their non-homogenous structures and non-standard materials to identify if they are able to perform …

Electrostrictive Polymers For Mechanical-To-Electrical Energy Harvesting, William G. Kaval, Ronald A. Coutu Jr., Robert A. Lake

Electrical and Computer Engineering Faculty Research and Publications

Research of electrostrictive polymers has generated new opportunities for harvesting energy from the surrounding environment and converting it into usable electrical energy. Piezoelectric ceramic based devices have long been used in energy harvesting for converting mechanical motion to electrical energy. Nevertheless, those materials tend to be unsuitable for low-frequency mechanical excitations such as human movement. Since organic polymers are typically softer and more flexible, the translated electrical energy output is considerably higher under the same mechanical force. Currently, investigations in using electroactive polymers for energy harvesting, and mechanical-to-electrical energy conversion, are beginning to show potential for this application. In this …

Design And Analysis Of Novel Ge-Gete Pn Junction For Photovoltaics, Andrew M. Jones, Ronald A. Coutu Jr., Robert A. Lake

Electrical and Computer Engineering Faculty Research and Publications

The continuing rise in demand for energy places a similarly increasing demand to improve power production methods and efficiency. In regards to solar power generation, one major limiting factor with existing photovoltaic (PV) systems is the management of heat produced and photon interactions with the PV device. Typical devices operate within the 300-1000 nm range of the solar spectrum, greatly limiting the range of photons used for power generation. Furthermore, since infrared light (

Enthalpy-Based System-Model For Pumped Two-Phase Cooling Systems, Leitao Chen, Fanghao Yang, Pritish R. Parida, Mark Schultz, Timothy Chainer

Publications

The development of embedded chip cooling for 2D and 3D integrated circuits using pumped dielectric refrigerant has gained recent attention due to the ability to manage high heat densities and compatibility with electronics. Recent studies have focused on in-situ thermal and hydrodynamic phenomena (e.g. boiling and bubble dynamics) of two-phase flow boiling at micro-scales. In this paper we focus on the two-phase cooling system design including the cooling capability, size and coefficient of performance (COP). In implementing a two-phase cooling, a system-level computational model for two-phase cooling systems becomes necessary. Therefore, a computationally manageable and accurate one dimensional (1D) system …

Enhancing Mobile Cloud Computing Security Using Steganography, Hassan Reza, Madhuri Sonawane

Computer Science Faculty Publications

Cloud computing is an emerging and popular method of accessing shared and dynamically configurable resources via the computer network on demand. Cloud computing is excessively used by mobile applications to offload data over the network to the cloud. There are some security and privacy concerns using both mobile devices to offload data to the facilities provided by the cloud providers. One of the critical threats facing cloud users is the unauthorized access by the insiders (cloud administrators) or the justification of location where the cloud providers operating. Although, there exist variety of security mechanisms to prevent unauthorized access by unauthorized …

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 …

3d Object Recognition For A Portable Robotic Navigation Aid, Xiangfei Qian

Theses and Dissertations

The objective of this dissertation is to develop a 3D object recognition method for a portable robotic navigation aid, called “Smart Cane” (SC), for the visually impaired. The SC is a computer-vision-enhanced white cane that uses a single 3D time-of-flight camera for navigation in an indoor environment. To achieve the navigation function, the SC should be able to perform SLAM (Simultaneous Localization And Mapping) and object recognition. In this dissertation, we focus on object recognition. Firstly, a method, named Normal-Coherence-Check RANSAC (RANdom Sample Consensus), is proposed to perform robust and fast plane extraction. Secondly, a 3D object recognition method based …

Fire-Spotting Modelling And Parametrisation For Wild-Land Fires, Inderpreet Kaur, Gianni Pagnini

International Congress on Environmental Modelling and Software

This article describes a mathematical formulation for simulating the effects of firebrands on the propagation of the wild-land fires. Among the different approaches available in literature, this formulation is defined in a way to provide a versatile approach for application to operational wildfire models. Most of the operational wildfire models like WRF-SFIRE and ForeFire model only the evolution of the fire-line according to the definition of the rate of spread, fuel characterisation and the average fire properties and concurrent atmospheric conditions. But this information is not enough to simulate the effects of turbulence and fire-spotting. The formulation presented here can …

A Generator Of Landuse Application For Complex And Heterogeneous Agricultural Practices, Odile Leccia-Phelpin, Jean-Marie Lescot, Françoise Vernier

International Congress on Environmental Modelling and Software

Non-point source pollution from agriculture has become a major concern for water managers and institutional stakeholders. To reduce diffuse pollution, agricultural conservation measures are widely used with efficiency. On non-monitored territories environmental modelling enables the assessment of their long term impacts on water and soils and to evaluate land-use change scenarios. We developed an innovative Generator of Landuse (GenLU) application in order to build up multi-year spatial crop successions from identified crop rotations with their related management schedule s. GenLU can be used solely for generating landuse or coupled with the Soil and Water Assessment Tool (SWAT) model so as …

Water Supply System Classification For Water Quality Improvement, Bruno Melo Brentan, Gustavo Meirelles Lima, Edevar Luvizotto Junior, Joaquín Izquierdo, Rafael Pérez-García

International Congress on Environmental Modelling and Software

Universal access to drinkable water is a constitutional right guaranteed in Brazil. However, not all cities in this country are able to supply the population with the expected quality. Important actions should be taken to improve the supply of drinkable water. To define a strategic plan for this purpose, classification tools can facilitate the design of plans, by grouping cities with similar quality conditions. During the last decades, neural network approaches have been used in environmental models, allowing more accurate representation of some complex systems. This work proposes the use of self-organizing maps (SOM’s) coupled with the k-means algorithm …

Optimal Land Use?! – A Review On Optimization Techniques Used In Multi-Criteria Decision Analysis, Andrea Kaim, Anna Cord, Martin Volk

International Congress on Environmental Modelling and Software

Agriculture, forest management, conservation planning and other related disciplines have specific land use demands, and thus different perspectives on how land should be used in an “optimal way”. One way to solve arising land use conflicts is employing the ecosystem services concept together with methods from the field of multi-criteria decision analysis (MCDA). Especially optimization techniques provide the possibility to include socio-economic and ecological aspects as well as the protection of biodiversity. In this study, we give an overview of these methods, focusing especially on their application in agricultural areas. We explore their abilities for the identification of ecosystem service …

The Economics Of Agricultural Water Productivity In The Blue Nile, Imeshi Weerasinghe, James Booker, Wim Bastiaanssen, Lisa-Marie Rebelo, Ann Van Griensven

International Congress on Environmental Modelling and Software

Agricultural Water Productivity (AWP) is often simplified as the ‘crop per drop’, described as the output in terms of yield or biomass per unit of water input. This purely physical measure of Water Productivity (WP) using only a single factor input (water) does not consider: (1) the level of other inputs used in conjunction with water, (2) the opportunity cost of water as an input, (3) the value of the output and (4) the costs of production for different crops. This study presents a justification and methodology for incorporating these factors into WP indicators. The application of these extensions to …

Atlas: A Tool To Model Spatial-Temporal Dynamics Of Processes Influencing Ecosystem Services, Hugo Thierry, Aude Vialatte, Claude Monteil, Annie Ouin

International Congress on Environmental Modelling and Software

Biodiversity provides various benefits to humankind throughout what is defined as ecosystem services. Within a specific ecosystem, a wide range of ecosystem services can be identified. During the past decades, human intervention has aimed to increase some services such as food production through agricultural intensification, at the expense of other services such as water regulation. Mapping, evaluating and quantifying each of these ecosystem services provided by biodiversity to crop production could help to increase the multi-functionality of agricultural landscapes. In this context, we developed a spatially-explicit model called ATLAS (AgriculTural LandscApe Simulator). ATLA …