Computer Engineering Commons^™

A Simple Algorithm For Triconnectivity Of A Multigraph, Abusayeed Saifullah, Alper Ungor

All Computer Science and Engineering Research

Vertex-connectivity and edge-connectivity represent the extent to which a graph is connected. Study of these key properties of graphs plays an important role in varieties of computer science applications. Recent years have witnessed a number of linear time 3-edge-connectivity algorithms - with increasing simplicity. In contrast, the state-of-the-art algorithm for 3-vertex-connectivity due to Hopcroft and Tarjan lacks the simplicity in the sense of ease of implementation as well as the number of passes over the graph although its time and space complexity is theoretically linear. In this paper, we propose a linear time reduction from 3-vertex-connectivity to 3-edge- connectivity of …

Partial Order Based Reduction In Planning: A Unifying Theory And New Algorithms, You Xi, Yixin Chen

All Computer Science and Engineering Research

Partial order based reduction (POR) has recently attracted research in planning. POR algorithms reduce search space by recognizing interchangable orders between actions and expanding only a subset of all possible orders during the search. POR has been extensively studied in model checking and proved to be an enabling technique for reducing the search space and costs. Recently, two POR algorithms, including the expansion core (EC) and stratified planning (SP) algorithms, have been proposed. Being orthogonal to the development of accurate heuristic functions, these reduction methods show great potential to improve the planning efficiency from a new perspective. However, it is …

Online Bayesian Analysis, Ruibin Xi, Yongjin Kim, Nan Lin, Yixin Chen, Gruia-Catalin Roman

All Computer Science and Engineering Research

In the last few years, there has been active research on aggregating advanced statistical measures in multidimensional data cubes from partitioned subsets of data. In this paper, we propose an online compression and aggregation scheme to support Bayesian estimations in data cubes based on the asymptotic properties of Bayesian statistics. In the proposed approach, we compress each data segment by retaining only the model parameters and a small amount of auxiliary measures. We then develop an aggregation formula that allows us to reconstruct the Bayesian estimation from partitioned segments with a small approximation error. We show that the Bayesian estimates …

Non-Programmers Identifying Functionality In Unfamiliar Code: Strategies And Barriers, Paul Gross, Caitlin Kelleher

All Computer Science and Engineering Research

Source code on the web is a widely available and potentially rich learning resource for non-programmers. However, unfamiliar code can be daunting to end-users without programming experience. This paper describes the results of an exploratory study in which we asked non-programmers to find and modify the code responsible for specific functionality within unfamiliar programs. We present two interacting models of how non-programmers approach this problem: the Task Process Model and the Landmark-Mapping model. Using these models, we describe code search strategies non-programmers employed and the difficulties they encountered. Finally, we propose guidelines for future programming environments that support non-programmers in …

Augmented Lagrangian Algorithms Under Constraint Partitioning, You Xu, Yixin Chen

All Computer Science and Engineering Research

We present a novel constraint-partitioning approach for solving continuous nonlinear optimization based on augmented Lagrange method. In contrast to previous work, our approach is based on a new constraint partitioning theory and can handle global constraints. We employ a hyper-graph partitioning method to recognize the problem structure. We prove global convergence under assumptions that are much more relaxed than previous work and solve problems as large as 40,000 variables that other solvers such as IPOPT [11] cannot solve.

Supercharged Planetlab Platform Architecture, Jonathan Turner, Patrick Crowley, John Dehart, Mart Haitjema, Fred Kuhns Kuhns, Ritun Patney, Michael Wilson, Charlie Wiseman, David Zar

All Computer Science and Engineering Research

This report describes the Supercharged Planetlab Platform (SPP), a system designed as a prototype of an internet-scale overlay hosting platform. Overlay networks have become an important vehicle for delivering Internet applications. Overlay network nodes are typically implemented using general purpose servers or clusters. The SPP offers a more integrated architecture, combining general-purpose servers with high performance Network Processor (NP) subsystems. SPP nodes have recently been deployed as part of the Global Environment for Network Innovation (GENI) and are available for use by research users.

Self-Stabilizing Computation Of 3-Edge-Connected Components, Abusayeed Saifullah, Yung Tsin

All Computer Science and Engineering Research

No abstract provided.

Scalable Scheduling Policy Design For Open Soft Real-Time Systems, Robert Glaubius, Terry Tidewell, Braden Sidoti, David Pilla, Justin Meden, Christopher Gill, William D. Smart

All Computer Science and Engineering Research

Open soft real-time systems, such as mobile robots, must respond adaptively to varying operating conditions, while balancing the need to perform multiple mission specific tasks against the requirement that those tasks complete in a timely manner. Setting and enforcing a utilization target for shared resources is a key mechanism for achieving this behavior. However, because of the uncertainty and non-preemptability of some tasks, key assumptions of classical scheduling approaches do not hold. In previous work we presented foundational methods for generating task scheduling policies to enforce proportional resource utilization for open soft real-time systems with these properties. However, these methods …

Design And Evaluation Of A Practical, High Performance Crossbar Scheduler, Jonathan Turner

All Computer Science and Engineering Research

The Least Occupied Output First (LOOFA) scheduler is one of several unbuffered crossbar schedulers that provides strong performance guarantees when operated with a speedup of 2 or more. Because LOOFA requires the computation of a maximal matching, it has been considered too slow for use in systems with link rates of 10 Gb/s or more. This paper studies an approximate variant of LOOFA described briefly in [16]. We introduce a general family of schedulers that allows for partial sorting and that includes the LOOFA scheduler as a special case. We show that all schedulers in this class are work-conserving and …

3d Reconstruction Using Multi-View Imaging System, Conglin Huang

University of Kentucky Master's Theses

This thesis presents a new system that reconstructs the 3D representation of dental casts. To maintain the integrity of the 3D representation, a standard model is built to cover the blind spots that the camera cannot reach. The standard model is obtained by scanning a real human mouth model with a laser scanner. Then the model is simplified by an algorithm which is based on iterative contraction of vertex pairs. The simplified standard model uses a local parametrization method to obtain the curvature information. The system uses a digital camera and a square tube mirror in front of the camera …

Performance-Engineered Network Overlays For High Quality Interaction In Virtual Worlds, Mart Haitjema, Ritun Patney, Jon Turner, Charlie Wiseman, John Dehart

All Computer Science and Engineering Research

Overlay hosting systems such as PlanetLab, and cloud computing environments such as Amazon’s EC2, provide shared infrastructures within which new applications can be developed and deployed on a global scale. This paper ex-plores how systems of this sort can be used to enable ad-vanced network services and sophisticated applications that use those services to enhance performance and provide a high quality user experience. Specifically, we investigate how advanced overlay hosting environments can be used to provide network services that enable scalable virtual world applications and other large-scale distributed applications requiring consistent, real-time performance. We propose a novel network architecture called …

Geodesic Grassfire For Computing Mixed-Dimensional Skeletons, Lu Liu, Tao Ju

All Computer Science and Engineering Research

Skeleton descriptors are commonly used to represent, understand and process shapes. While existing methods produce skeletons at a fixed dimension, such as surface or curve skeletons for a 3D object, often times objects are better described using skeleton geometry at a mixture of dimensions. In this paper we present a novel algorithm for computing mixed-dimensional skeletons. Our method is guided by a continuous analogue that extends the classical grassfire erosion. This analogue allows us to identify medial geometry at multiple dimensions, and to formulate a measure that captures how well an object part is described by medial geometry at a …

Enhanced Coordination In Sensor Networks Through Flexible Service Provisioning, Chien-Liang Fok, Gruia-Catalin Roman, Chenyang Lu

All Computer Science and Engineering Research

Heterogeneous wireless sensor networks represent a challenging programming environment. Servilla addresses this by offering a new middleware framework that provides service provisioning. Using Servilla, developers can construct platform-independent applications over a dynamic set of devices with diverse computational resources and sensors. A salient feature of Servilla is its support for dynamic discovery and binding to local and remote services, which enables flexible and energy-efficient in-network collaboration among heterogeneous devices. Furthermore, Servilla provides a modular middleware architecture that can be easily tailored for devices with a wide range of resources, allowing resource-constrained devices to provide services while leveraging the capabilities of …

Throughput-Optimal Systolic Arrays From Recurrence Equations, Arpith C. Jacob, Jeremy D. Buhler, Roger D. Chamberlain

All Computer Science and Engineering Research

Many compute-bound software kernels have seen order-of-magnitude speedups on special-purpose accelerators built on specialized architectures such as field-programmable gate arrays (FPGAs). These architectures are particularly good at implementing dynamic programming algorithms that can be expressed as systems of recurrence equations, which in turn can be realized as systolic array designs. To efficiently find good realizations of an algorithm for a given hardware platform, we pursue software tools that can search the space of possible parallel array designs to optimize various design criteria. Most existing design tools in this area produce a design that is latency-space optimal. However, we instead wish …

The Virtual Network Scheduling Problem For Heterogeneous Network Emulation Testbeds, Charlie Wisemen, Jonathan Turner

All Computer Science and Engineering Research

Network testbeds such as Emulab and the Open Network Laboratory use virtualization to enable users to define end user virtual networks within a shared substrate. This involves mapping users' virtual network nodes onto distinct substrate components and mapping virtual network links onto substrate paths. The mappings guarantee that different users' activities can not interfere with one another. The problem of mapping virtual networks onto a shared substrate is a variant of the general graph embedding problem, long known to be NP-hard. In this paper, we focus on a more general version of the problem that supports advance scheduling of virtual …

Architectures For The Future Networks And The Next Generation Internet: A Survey, Subharthi Paul, Jianli Pan, Raj Jain

All Computer Science and Engineering Research

Networking research funding agencies in the USA, Europe, Japan, and other countries are encouraging research on revolutionary networking architectures that may or may not be bound by the restrictions of the current TCP/IP based Internet. We present a comprehensive survey of such research projects and activities. The topics covered include various testbeds for experimentations for new architectures, new security mechanisms, content delivery mechanisms, management and control frameworks, service architectures, and routing mechanisms. Delay/Disruption tolerant networks, which allow communications even when complete end-to-end path is not available, are also discussed.

Defending Against Distributed Denial-Of-Service Attacks With Weight-Fair Router Throttling, Abusayeed Saifullah

All Computer Science and Engineering Research

A high profile internet server is always a target of denial-of-service attacks. In this paper, we propose a novel technique for protecting an internet server from distributed denial-of-service attacks. The defense mechanism is based on a distributed algorithm that performs weight-fair throttling at the upstream routers. The throttling is weight-fair because the traffics destined for the server are controlled increased or decreased ) by the leaky-buckets at the routers based on the number of users connected, directly or through other routers, to each router. To the best of our knowledge, this is the first weight-fair technique for saving an internet …

Open Workflows: Context-Dependent Construction And Execution In Mobile Wireless Settings, Louis Thomas, Justin Wilson, Grui-Catalin Roman, Christopher Gill

All Computer Science and Engineering Research

Existing workflow middleware executes tasks orchestrated by rules defined in a carefully handcrafted static graph. Workflow management systems have proved effective for service-oriented business automation in stable, wired infrastructures. We introduce a radically new paradigm for workflow construction and execution called open workflow to support goal-directed coordination among physically mobile people and devices that form a transient community over an ad hoc wireless network. The quintessential feature of the open workflow paradigm is dynamic construction and execution of custom, context-specific workflows in response to unpredictable and evolving circumstances by exploiting the knowledge and services available within a given spatiotemporal context. …

Globally Clocked Magnetic Logic Circuits, Michael Hall, Albrecht Jander, Roger D. Chamberlain, Pallavi Dhagat

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Magnetic spin valve devices enable the design of logic and memory elements that are suitable for use when constructing digital systems. A master-slave flip-flop design is proposed that can be clocked using an externally applied global magnetic field. With an external global clock, the digital system no longer needs to deliver the clock on-chip, thereby eliminating the need for a clock distribution network. We assess the power, area, and speed implications associated with the ability to eliminate the clock distribution network on a hybrid CMOS-magnetologic digital system.

Adaptive Service Provisioning For Wireless Sensor Networks, Chien-Liang Fok, Gruia-Catalin Roman, Chenyang Lu

All Computer Science and Engineering Research

Service provisioning has gained significant attention as a promising programming model for heterogeneous wireless sensor networks. Its key idea is to exploit the decoupling of service providers and consumers to enable platform-independent applications that are dynamically bound to platform-specific services. We explore novel adaptive service binding strategies that are able to cope with network dynamics and to promote energy conservation. To achieve this goal, we developed policies and algorithms that automatically switch providers in response to network topology changes and adapt application behavior when opportunities for energy savings surface. The latter is accomplished by providing limited information about the energy …

Efficient Tracking Of Many Objects In Structured Environments, Nathan Jacobs, Michael Dixon, Scott Satkin, Robert Pless

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We consider the special case of tracking objects in highly structured scenes. In the context of vehicle tracking in urban environments, we offer a fully automatic, end-to-end system that discovers and parametrizes the lanes along which vehicles drive, then uses just these pixels to simultaneously track dozens of objects. This system includes a novel active contour energy function used to parametrize the lanes of travel based only on the accumulation of spatio-temporal image derivatives, and a tracking algorithm that exploits longer temporal constraints made possible by our compact data representation; we believe both of these may be of independent interest. …

A Cryptanalysis Methodology For The Reverse Engineering Of Encrypted Information In Images, Allan Anthony Rwabutaza

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Security is an important issue related to the storage and communication of data and information. In data and information security, cryptography and steganography are two of the most common security techniques. On one hand, there is cryptography, which is the secret communication between two parties by message scrambling on the sender's side and message unscrambling on the receiver's side so that only the intended receiver gets the secret message. On the other hand, there is steganography, which is the hiding of information in a medium in such a way that no one other than the sender or the intended receiver …

Hierarchical Routing In Manets Using Simple Clustering, Adam Carnine

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis presents both a review of current MANET routing protocols and a new MANET routing algorithm. The routing protocols reviewed include representative samples from the three primary forms of routing found in MANETS: proactive routing, reactive routing and hybrid routing. Secure algorithms are given special treatment in the review. In addition several protocol enhancements are discussed.

The proposed routing protocol is designed to support networks of a medium size, containing over 200 nodes but less than 3,000 nodes. The design is intentionally simple to allow ease of implementation in comparison with other MANET protocols that provide similar functionality.

Telecommunications Liberalisation In Africa: Proposed Regulatory Model For The Sadc Region, Z. N. Jobodwana

Journal of Digital Forensics, Security and Law

The liberalisation of the telecommunication industry in Africa, and the further development of the region’s physical infrastructure was accompanied by the further development of Africa’s information, communication and technology infrastructure. Competition within the industry stimulated heavy economic investment in other sectors of the economy. The outcome of liberalisation also included the establishment of community-based structures that continue to enable communities to manage their own development and gain access to information and communication technologies (ICTs) in an unprecedented manner. The telecommunication infrastructure further stimulated the fast development of other related services, for example, ecommerce and mobile commerce (m-commerce), e-government, internet banking, …

Self-Reported Cyber Crime: An Analysis On The Effects Of Anonymity And Pre-Employment Integrity, Ibrahim Baggili, Marcus Rogers

Electrical & Computer Engineering and Computer Science Faculty Publications

A key issue facing today’s society is the increase in cyber crimes. Cyber crimes pose threats to nations, organizations and individuals across the globe. Much of the research in cyber crime has risen from computer science-centric programs, and little experimental research has been performed on the psychology of cyber crime. This has caused a knowledge gap in the study of cyber crime. To this end, this research focuses on understanding psychological concepts related to cyber crime. Through an experimental design, participants were randomly assigned to three groups with varying degrees of anonymity. After each treatment, participants were asked to self-report …

Tyflos: A Wearable Navigation Prototype For Blind & Visually Impaired; Design, Modelling And Experimental Results, Dimitrios Dakopoulos

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The need for assistive devices has, had and will have a large merit in many engineering research arenas. This dissertation deals with the design, modeling, implementation and experimentation of the navigation component of a wearable assistive system for blind and visually impaired people, called TYFLOS (ΤΥΦΛΟΣ) which is the Greek word for "Blind".

The current prototype consists of two mini cameras attached to a pair of conventional eye-glasses, a 2D tactile display vibration array) which consists of 16 vibrating elements arranged in a 4x4 manner, attached to an elastic vest worn on the user's abdomen, a portable computer, an ear-speaker …

Semantics Enriched Service Environments, Karthik Rajagopal Gomadam

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During the past seven years services centric computing has emerged as the preferred approach to architect complex software. Software is increasingly developed by integrating remotely existing components, popularly called services. This architectural paradigm, also called Service Oriented Architecture (SOA), brings with it the benefits of interoperability, agility and flexibility to software design and development. One can easily add or change new features to existing systems, either by the addition of new services or by replacing existing ones. Two popular approaches have emerged for realizing SOA. The first approach is based on the SOAP protocol for communication and the Web Service …

Burst Scheduling, Grooming And Qos Provisioning In Optical Burst-Switched Networks, Yuqi Fan

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The demand of network capacity has been increasing steadily with more users than ever connected to the Internet through broadband access and the popularity of video based applications, such as YouTube. Optical wavelength division multiplexing (WDM) networks are expected to form the next-generation backbone network and to fulfill the insatiable appetite for bandwidth.

Wavelength routed WDM optical networks offer the granularity of switching at a fiber, waveband, or a wavelength level. The finest granularity offered is at a wavelength level by provisioning lightpaths for different clients/services. All-optical packet switching is still deemed technically infeasible and its competitiveness as a backbone …

Improving Remote Homology Detection Using A Sequence Property Approach, Gina Marie Cooper

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Understanding the structure and function of proteins is a key part of understanding biological systems. Although proteins are complex biological macromolecules, they are made up of only 20 basic building blocks known as amino acids. The makeup of a protein can be described as a sequence of amino acids. One of the most important tools in modern bioinformatics is the ability to search for biological sequences (such as protein sequences) that are similar to a given query sequence. There are many tools for doing this (Altschul et al., 1990, Hobohm and Sander, 1995, Thomson et al., 1994, Karplus and Barrett, …

Design And Performance Analysis Of A Secure Proces-Sor Scan-Sp With Crypto-Biometric Capabilities, Raghudeep Kannavara

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Secure computing is gaining importance in recent times as computing capability is increasingly becoming distributed and information is everywhere. Prevention of piracy and digital rights management has become very important. Information security is mandatory rather than an additional feature. Numerous software techniques have been proposed to provide certain level of copyright and intellectual property protection. Techniques like obfuscation attempt to transform the code into a form that is harder to reverse engineer. Tamper-proofing causes a program to malfunction when it detects that it has been modified. Software watermarking embeds copyright notice in the software code to allow the owners of …