Engineering Commons^™

Autoplug: An Automated Metadata Service For Smart Outlets, Lurdh Pradeep Reddy Ambati

Masters Theses

Low-cost network-connected smart outlets are now available for monitoring, controlling, and scheduling the energy usage of electrical devices. As a result, such smart outlets are being integrated into automated home management systems, which remotely control them by analyzing and interpreting their data. However, to effectively interpret data and control devices, the system must know the type of device that is plugged into each smart outlet. Existing systems require users to manually input and maintain the outlet metadata that associates a device type with a smart outlet. Such manual operation is time-consuming and error-prone: users must initially inventory all outlet-to-device mappings, …

Analyzing Spark Performance On Spot Instances, Jiannan Tian

Masters Theses

Amazon Spot Instances provide inexpensive service for high-performance computing. With spot instances, it is possible to get at most 90% off as discount in costs by bidding spare Amazon Elastic Computer Cloud (Amazon EC2) instances. In exchange for low cost, spot instances bring the reduced reliability onto the computing environment, because this kind of instance could be revoked abruptly by the providers due to supply and demand, and higher-priority customers are first served.

To achieve high performance on instances with compromised reliability, Spark is applied to run jobs. In this thesis, a wide set of spark experiments are conducted to …

Numerical Simulation Of Multi-Phase Core-Shell Molten Metal Drop Oscillations, Kaushal Sumaria

Masters Theses

The surface tension of liquid metals is an important and scientifically interesting parameter which affects many metallurgical processes such as casting, welding and melt spinning. Conventional methods for measuring surface tension are difficult to use for molten metals above temperatures of 1000 K. Containerless methods are can be used to measure the surface tension of molten metals above 1000 K. Oscillating drop method is one such method where a levitated droplet is allowed to undergo damped oscillations. Using the Rayleigh’s theory for the oscillation of force-free inviscid spherical droplets, surface tension and viscosity of the sample can be calculated from …

Effects Of Malformed Or Absent Valves To Lymphatic Fluid Transport And Lymphedema In Vivo In Mice, Akshay S. Pujari

Masters Theses

Lymph is primarily composed of fluid and proteins from the blood circulatory system that drain into the space surrounding cells, interstitial space. From the interstitial space, the fluid enters and circulates in the lymphatic system until it is delivered into the venous system. In contrast to the blood circulatory system, the lymphatic system lacks a central pumping organ dictating the predominant driving pressure and velocity of lymph. Transport of lymph via capillaries, pre-collecting and collecting lymphatic vessels relies on the synergy between pressure gradients, local tissue motion, valves and lymphatic vessel contractility. The direction of lymph transport is regulated by …

Non-Equispaced Fast Fourier Transforms In Turbulence Simulation, Aditya M. Kulkarni

Masters Theses

Fourier pseudo-spectral method on equispaced grid is one of the approaches in turbulence simulation, to compute derivative of discrete data, using fast Fourier Transform (FFT) and gives low dispersion and dissipation errors. In many turbulent flows the dynamically important scales of motion are concentrated in certain regions which requires a coarser grid for higher accuracy. A coarser grid in other regions minimizes the memory requirement. This requires the use of Non-equispaced Fast Fourier Transform (NFFT) to compute the Fourier transform, by solving a system of linear equations.

To achieve similar accuracy, the NFFT needs to return more Fourier coefficients than …

Energy Efficient Loop Unrolling For Low-Cost Fpgas, Naveen Kumar Dumpala

Masters Theses

Many embedded applications implement block ciphers and sorting and searching algorithms which use multiple loop iterations for computation. These applications often demand low power operation. The power consumption of designs varies with the implementation choices made by designers. The sequential implementation of loop operations consumes minimal area, but latency and clock power are high. Alternatively, loop unrolling causes high glitch power. In this work, we propose a low area overhead approach for unrolling loop iterations that exhibits reduced glitch power. A latch based glitch filter is introduced that reduces the propagation of glitches from one iteration to next. We explore …

Navigation Instruction Validation Tool And Indoor Wayfinding Training System For People With Disabilities, Linlin Ding

Masters Theses

According to World Health Survey, there are 785 million (15.6%) people in the world that live with a disability. It is a well-known fact that lack of access to public transportation is a barrier for people with disabilities in seeking work or accessing health care. In this research, we seek to increase access to public transportation by introducing a virtual pre-travel training system that enables people with disabilities to get familiar with a public transportation venue prior to arriving at the venue. Using this system, users establish a mental map of the target environment prior to their arrival to the …

Evaluation Of Impedance Control On A Powered Hip Exoskeleton, Punith Condoor

Masters Theses

This thesis presents an impedance control strategy for a novel powered hip exoskeleton designed to provide partial assistance and leverage the dynamics of human gait. The control strategy is based on impedance control and provides the user assistance as needed which is determined by the user’s interaction with the exoskeleton. A series elastic element is used to drive the exoskeleton and measures the interaction torque between the user and the device. The device operates in two modes. Free mode is a low impedance state that attempts to provide no assistance. Assist mode increases the gains of the controller to provide …

Efficient Scaling Of A Web Proxy Cluster, Hao Zhang

Masters Theses

With the continuing growth in network traffic and increasing diversity in web content, web caching, together with various network functions (NFs), has been introduced to enhance security, optimize network performance, and save expenses. In a large enterprise network with more than tens of thousands of users, a single proxy server is not enough to handle a large number of requests and turns to group processing. When multiple web cache proxies are working as a cluster, they talk with each other and share cached objects by using internet cache protocol (ICP). This leads to poor scalability.

This thesis describes the development …

Query On Knowledge Graphs With Hierarchical Relationships, Kaihua Liu

Masters Theses

The dramatic popularity of graph database has resulted in a growing interest in graph queries. Two major topics are included in graph queries. One is based on structural relationship to find meaningful results, such as subgraph pattern match and shortest-path query. The other one focuses on semantic-based query to find question answering from knowledge bases. However, most of these queries take knowledge graphs as flat forms and use only normal relationship to mine these graphs, which may lead to mistakes in the query results. In this thesis, we find hierarchical relationship in the knowledge on their semantic relations and make …

Magneto-Electric Approximate Computational Framework For Bayesian Inference, Sourabh Kulkarni

Masters Theses

Probabilistic graphical models like Bayesian Networks (BNs) are powerful artificial-intelligence formalisms, with similarities to cognition and higher order reasoning in the human brain. These models have been, to great success, applied to several challenging real-world applications. Use of these formalisms to a greater set of applications is impeded by the limitations of the currently used software-based implementations. New emerging-technology based circuit paradigms which leverage physical equivalence, i.e., operating directly on probabilities vs. introducing layers of abstraction, promise orders of magnitude increase in performance and efficiency of BN implementations, enabling networks with millions of random variables. While majority of applications with …

Bmi, Tumor Lesion And Probability Of Femur Fracture: A Probabilistic Biomechanics Approach, Zhi Gao

Masters Theses

found that most of these factors are directly or indirectly linked to subjects’ BMI (body mass index). Thus, from a statistical perspective, BMI could be an overall indicator of the probability of femur fracture from a sideways fall. Using a biomechanics approach coupled with statistical data we investigate this relationship with a large cohort of postmenopausal women aged 50-79 from WHI-OS (Women’s Health Initiative Observational Cohort). The cohort is divided into six sub-cohorts by BMI where each fall-related factor is examined and compared with each other. Significant differences are discovered among cohorts in terms of femur size, aBMD (areal bone …

Skynet: Memristor-Based 3d Ic For Artificial Neural Networks, Sachin Bhat

Masters Theses

Hardware implementations of artificial neural networks (ANNs) have become feasible due to the advent of persistent 2-terminal devices such as memristor, phase change memory, MTJs, etc. Hybrid memristor crossbar/CMOS systems have been studied extensively and demonstrated experimentally. In these circuits, memristors located at each cross point in a crossbar are, however, stacked on top of CMOS circuits using back end of line processing (BOEL), limiting scaling. Each neuron’s functionality is spread across layers of CMOS and memristor crossbar and thus cannot support the required connectivity to implement large-scale multi-layered ANNs.

This work proposes a new fine-grained 3D integrated circuit technology …

Oracle Guided Incremental Sat Solving To Reverse Engineer Camouflaged Circuits, Xiangyu Zhang

Masters Theses

This study comprises two tasks. The first is to implement gate-level circuit camouflage techniques. The second is to implement the Oracle-guided incremental de-camouflage algorithm and apply it to the camouflaged designs.

The circuit camouflage algorithms are implemented in Python, and the Oracle- guided incremental de-camouflage algorithm is implemented in C++. During this study, I evaluate the Oracle-guided de-camouflage tool (Solver, in short) performance by de-obfuscating the ISCAS-85 combinational benchmarks, which are camouflaged by the camouflage algorithms. The results show that Solver is able to efficiently de-obfuscate the ISCAS-85 benchmarks regardless of camouflaging style, and is able to do so 10.5x …

Electroless Deposition & Electroplating Of Nickel On Chromium-Nickel Carbide Powder, Jeffrey Rigali

Masters Theses

Engineered components can gain desirable properties when coated with surface materials. Wear-resistant coatings can improve the performance of contacting surfaces and allow for an extended life of the parts. Hard chromium has been the plating material of choice for certain wear and corrosion- resistant coatings because of its desirable combination of chemical resistance, adhesion, and mechanical properties. However, hexavalent chromium, a component of the process for applying hard chromium coatings, has been recognized by the EPA as having hazardous health and environmental impacts. Existing and planned environmental regulations restricts the use of process chemicals containing hexavalent chromium ions. This substantiates …

Improving The Efficiency Of Wind Farm Turbines Using External Airfoils, Shujaut Bader

Masters Theses

Wind turbine efficiency typically focuses on the shape, orientation, or stiffness of the turbine blades. In this thesis, the focus is instead on using static fixed airfoils in proximity to the wind turbine to control the airflow coming out of the turbine. These control devices have three beneficial effects. (1) They gather air from “higher up” where the air is moving faster on average (and therefore has more kinetic energy in it). (2) They throw the used (and slowed down air) downwards. This means that any turbines in the wind farm behind the lead turbines do not get “stale” air. …

Performance Of Adhesive And Cementitious Anchorage Systems, Mirna Mendoza

Masters Theses

Post-installed anchoring systems are used extensively in Massachusetts Department of Transportation (MassDOT) projects due their ease of attachment to existing structures. However, recommendations on materials from various manufacturers are currently lacking for certain situations such as long-term tension loading. The purpose of the investigation presented in this thesis was to provide guidance on the use of anchoring systems to MassDOT. This research project evaluated the behavior of adhesive and cementitious bonded anchoring systems per the Stress-versus-Time-to-Failure approach found in the provisional standard AASHTO TP-84 in order to provide recommendations pertaining to the test method. Supplemental short-term anchor pullout tests were …

Incorporating Seasonal Wind Resource And Electricity Price Data Into Wind Farm Micrositing, Timothy A. Pfeiffer

Masters Theses

Currently, most micrositing techniques aim to maximize annual energy production (AEP) or minimize cost of energy (COE) with no direct regard to revenue. This research study developed a method that utilizes the seasonal electricity price and wind data to microsite wind farms in terms of profitability. To accomplish this, six candidate wind farms with differing layouts and spacing were selected at a given location. They were then simulated using a wake modeling software to produce expected power outputs at different wind speeds, wind directions, and turbulence intensities. By interpolating the power output tables with wind data, a power time-series was …

Virtualization Of Closed-Loop Sensor Networks, Priyanka Dattatri Kedalagudde

Masters Theses

The existing closed-loop sensor networks are based on architectures that are designed and implemented for one specific application and require dedicated sensing and computational resources. This prevents the sharing of these networks. In this work, we propose an architecture of virtualization to allow sharing of closed-loop sensor networks. We also propose a scheduling approach that will manage requests from competing applications and evaluate their impact on system utilization against utilization achieved by more traditional, dedicated sensor networks. These algorithms are evaluated through trace-driven simulations, where the trace data is taken from CASA’s closed-loop weather radar sensor network. Results from this …

A Magnetic Resonance Compatible Knee Extension Ergometer, Youssef Jaber

Masters Theses

The product of this thesis aims to enable the study of the biochemical and physical dynamics of the lower limbs at high levels of muscle tension and fast contraction speeds. This is accomplished in part by a magnetic resonance (MR) compatible ergometer designed to apply a load as a torque of up to 420 Nm acting against knee extension at speeds as high as 4.7 rad/s. The system can also be adapted to apply the load as a force of up to 1200 N acting against full leg extension. The ergometer is designed to enable the use of magnetic resonance …

Experimental Study On Viscoelastic Fluid-Structure Interactions, Anita Anup Dey

Masters Theses

It is well known that when a flexible or flexibly-mounted structure is placed perpendicular to the flow of a Newtonian fluid, it can oscillate due to the shedding of separated vortices at high Reynolds numbers. If the same flexible object is placed in non-Newtonian flows, however, the structure's response is still unknown. The main objective of this thesis is to introduce a new field of viscoelastic fluid-structure interactions by showing that the elastic instabilities that occur in the flow of viscoelastic fluids can drive the motion of a flexible structure placed in its path. Unlike Newtonian fluids, the flow of …

Development Of High Early-Strength Concrete For Accelerated Bridge Construction Closure Pour Connections, Stephanie Castine

Masters Theses

Accelerated bridge construction (ABC) has become a popular alternative to using traditional construction techniques in new bridge construction and existing bridge deck replacement because of the reduction of time spent in field activities. A key feature of bridges built using ABC techniques is the extensive use of prefabricated components. Prefabricated components are joined in the field using small volume closure pours involving high performance materials (steel and concrete) to ensure adequate transfer of forces between components. To date, the materials developed for closure pours have been based on proprietary components, so a need has arisen for development of mixes that …

Evaluating Variances Between Departments Of Transportation In New England To Create A Strategic Transportation Workforce, Chelsea Bouchard

Masters Theses

As the baby boomer generation approaches retirement, the transportation workforce is increasingly under strain. Employees are exiting the industry in larger volumes than incoming hires; which is creating a need to reevaluate and revamp work processes. In addition, the industry is transitioning into the 21st century and that is requiring the adaptation of new technologies. The gap between old and new employee skills is growing and seen throughout the industry. There is a growing need and opportunity to develop a new set of job competencies which create job specifications and job postings, which support the organization’s strategic plan. In this …

Evaluation Of New England Bridges For Bat Roosting Including Methodology And Case Studies, Angela Berthaume

Masters Theses

Bats are known and documented to use bridge structures as roosts in various locations throughout the United States and abroad, but there is limited knowledge of how bats use bridges in New England. Significant population declines due to White-Nose Syndrome have resulted in several bat species being listed as state or federally threatened or endangered. If bats are using bridges as roosts, significant effort is required to ensure they are not disturbed or harmed during construction or maintenance work, requiring knowledge of assessment methods to identify likely roost locations in bridges. This thesis describes a two summer study evaluating the …

Indoor Navigation For The Blind And Visually Impaired: Validation And Training Methodology Using Virtual Reality, Sili Wang

Masters Theses

In this thesis we propose a navigation instruction validation tool and an user training tool for PERCEPT system.

The validation tool evaluates the navigation instructions using a virtual reality environment by ensuring that each path in the virtual environment can be traversed by following the navigation instructions. This validation tool will serve as a first automatic validation of navigation instructions prior to testing them with blind and visually impaired users.

The user-training tool enables the blind user to explore and get familiar with the real environment by using the virtual environment generated in the Unity3d based game. The user interacts …

Kasi: A Ka-Band And S-Band Cross-Track Interferometer, Gerard Ruiz Carregal

Masters Theses

A dual-frequency system is needed to better understand natural processes that constitute the environment and seasonal cycles of the Earth. A system working at two different wavelengths acquiring data simultaneously will give a valuable dataset since the conditions on the ground will be exactly the same. Hence, elements such as wind, soil moisture or any other changes on the ground will not interfere in the mea- surements. This thesis explains how an S-band radar was built and tested. Moreover, the experiments done with a Ka-band radar used as a scatterometer are explained as well as the data processing and analysis. …

Explorations Into Machine Learning Techniques For Precipitation Nowcasting, Aditya Nagarajan

Masters Theses

Recent advances in cloud-based big-data technologies now makes data driven solutions feasible for increasing numbers of scientific computing applications. One such data driven solution approach is machine learning where patterns in large data sets are brought to the surface by finding complex mathematical relationships within the data. Nowcasting or short-term prediction of rainfall in a given region is an important problem in meteorology. In this thesis we explore the nowcasting problem through a data driven approach by formulating it as a machine learning problem.

State-of-the-art nowcasting systems today are based on numerical models which describe the physical processes leading to …

Achieving Perfect Location Privacy In Wireless Devices Using Anonymization, Zarrin Montazeri

Masters Theses

The popularity of mobile devices and location-based services (LBS) have created great concerns regarding the location privacy of the users of such devices and services. Anonymization is a common technique that is often being used to protect the location privacy of LBS users. This technique assigns a random pseudonym to each user and these pseudonyms can change over time. Here, we provide a general information theoretic definition for perfect location privacy and prove that perfect location privacy is achievable for mobile devices when using the anonymization technique appropriately. First, we assume that the user’s current location is independent from her …

High Performance Silver Diffusive Memristors For Future Computing, Rivu Midya

Masters Theses

Sneak path current is a significant remaining obstacle to the utilization of large crossbar arrays for non-volatile memories and other applications of memristors. A two-terminal selector device with an extremely large current-voltage nonlinearity and low leakage current could solve this problem. We present here a Ag/oxide-based threshold switching (TS) device with attractive features such as high current-voltage nonlinearity (~10¹⁰), steep turn-on slope (less than 1 mV/dec), low OFF-state leakage current (~10^-14 A), fast turn ON/OFF speeds (<75/250 ns), and good endurance (>10⁸ cycles). The feasibility of using this selector with a typical memristor has been demonstrated by physically integrating them …

Time Domain Sar Processing With Gpus For Airborne Platforms, Dustin Lagoy

Masters Theses

A time-domain backprojection processor for airborne synthetic aperture radar (SAR) has been developed at the University of Massachusetts’ Microwave Remote Sensing Lab (MIRSL). The aim of this work is to produce a SAR processor capable of addressing the motion compensation issues faced by frequency-domain processing algorithms, in order to create well focused SAR imagery suitable for interferometry. The time-domain backprojection algorithm inherently compensates for non-linear platform motion, dependent on the availability of accurate measurements of the motion. The implementation must manage the relatively high computational burden of the backprojection algorithm, which is done using modern graphics processing units (GPUs), programmed …