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2009

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Articles 1 - 30 of 485

Full-Text Articles in Computer Engineering

Soft-Error Resilient On-Chip Memory Structures, Shuai Wang Dec 2009

Soft-Error Resilient On-Chip Memory Structures, Shuai Wang

Dissertations

Soft errors induced by energetic particle strikes in on-chip memory structures, such as L1 data/instruction caches and register files, have become an increasing challenge in designing new generation reliable microprocessors. Due to their transient/random nature, soft errors cannot be captured by traditional verification and testing process due to the irrelevancy to the correctness of the logic. This dissertation is thus focusing on the reliability characterization and cost-effective reliable design of on-chip memories against soft errors.

Due to various performance, area/size, and energy constraints in various target systems, many existing unoptimized protection schemes on cache memories may eventually ...


Control For Localization And Visibility Maintenance Of An Independent Agent Using Robotic Teams, Ethan A. Stump Dec 2009

Control For Localization And Visibility Maintenance Of An Independent Agent Using Robotic Teams, Ethan A. Stump

Publicly Accessible Penn Dissertations

Given a non-cooperative agent, we seek to formulate a control strategy to enable a team of robots to localize and track the agent in a complex but known environment while maintaining a continuously optimized line-of-sight communication chain to a fixed base station. We focus on two aspects of the problem. First, we investigate the estimation of the agent's location by using nonlinear sensing modalities, in particular that of range-only sensing, and formulate a control strategy based on improving this estimation using one or more robots working to independently gather information. Second, we develop methods to plan and sequence robot ...


Configuration Recognition, Communication Fault Tolerance And Self-Reassembly For The Ckbot, Michael G. Park Dec 2009

Configuration Recognition, Communication Fault Tolerance And Self-Reassembly For The Ckbot, Michael G. Park

Publicly Accessible Penn Dissertations

We present and experimentally verify novel methods for increasing the generality of control, autonomy and reliability for modular robotic systems. In particular, we demonstrate configuration recognition, distributed communication fault tolerance, and the organization and control of self-reassembly with the Connector Kinetic roBot (CKBot). The primary contribution of this work is the presentation and experimental verification of these innovative methods that are general and applicable to other modular robotic systems. We describe our CKBot system and compare it to other similar, state-of-the-art modular robotic systems. Our description and comparison highlights various design developments, features, and notable achievements of these systems. We ...


Interactions, Competition And Innovation In A Service-Oriented Internet: An Economic Model, Zhi-Li Zhang, Papak Nabipay, Andrew Odlyzko, Roch A. Guérin Dec 2009

Interactions, Competition And Innovation In A Service-Oriented Internet: An Economic Model, Zhi-Li Zhang, Papak Nabipay, Andrew Odlyzko, Roch A. Guérin

Departmental Papers (ESE)

This paper presents a new economic approach for studying competition and innovation in a complex and highly interactive system of network providers, users, and suppliers of digital goods and services (i.e., service providers). It employs Cournot and Bertrand games to model competition among service providers and network providers, respectively, and develops a novel unified model to capture the interaction and competition among these players in a “service-oriented” Internet. Incentives for service and network innovation are studied in this model.


Modeling And Computer Simulation Of Fault Calculations For Transmission Lines, Dr. Adel A. Elbaset Dec 2009

Modeling And Computer Simulation Of Fault Calculations For Transmission Lines, Dr. Adel A. Elbaset

Dr. Adel A. Elbaset

Calculation of transmission line faults has a fundamental importance in the fault detection, classification, and location determination of faults in transmission line. This paper presents a proposed computer program based on Matlab software to calculate all ten types of shunt faults that may occur in a transmission line. Various fault scenarios (fault types, fault locations and fault impedance) are considered in this paper. The inputs of the proposed program are line length, source voltage, positive, negative and zero sequence for source impedance, line charging, and transmission line impedance. The output of the algorithm is used to train an artificial intelligence ...


On The Feasibility And Efficacy Of Protection Routing In Ip Networks, Kin-Wah (Eric) Kwong, Lixin Gao, Roch A. Guérin, Zhi-Li Zhang Dec 2009

On The Feasibility And Efficacy Of Protection Routing In Ip Networks, Kin-Wah (Eric) Kwong, Lixin Gao, Roch A. Guérin, Zhi-Li Zhang

Departmental Papers (ESE)

With network components increasingly reliable, routing is playing an ever greater role in determining network reliability. This has spurred much activity in improving routing stability and reaction to failures, and rekindled interest in centralized routing solutions, at least within a single routing domain. Centralizing decisions eliminates uncertainty and many inconsistencies, and offers added flexibility in computing routes that meet different criteria. However, it also introduces new challenges; especially in reacting to failures where centralization can increase latency. This paper leverages the flexibility afforded by centralized routing to address these challenges. Specifically, we explore when and how standby backup forwarding options ...


Tailored Systems Architecture For Design Of Space Science And Technology Missions Using Dodaf V2.0, Nicholas J. Merski Dec 2009

Tailored Systems Architecture For Design Of Space Science And Technology Missions Using Dodaf V2.0, Nicholas J. Merski

Theses and Dissertations

The use of systems architecture, following a set of integrated descriptions from an architecture framework, has been well codified in Department of Defense acquisition and systems engineering. However, in the Space Science and Technology (S&T) community, this guidance and practice is not commonly adopted. This paper outlines an approach to leverage the changes made in DoD Architecture Framework 2.0 (DoDAF2.0), and the renewed emphasis on data and support to acquisition decision analysis. After decomposing the Space S&T design lifecycle into phases, design milestones and activities using process models, a set of DoDAF prescribed and Fit-for-Purpose views ...


Performance Analysis Of Live-Virtual-Constructive And Distributed Virtual Simulations: Defining Requirements In Terms Of Temporal Consistency, Douglas D. Hodson Dec 2009

Performance Analysis Of Live-Virtual-Constructive And Distributed Virtual Simulations: Defining Requirements In Terms Of Temporal Consistency, Douglas D. Hodson

Theses and Dissertations

This research extends the knowledge of live-virtual-constructive (LVC) and distributed virtual simulations (DVS) through a detailed analysis and characterization of their underlying computing architecture. LVCs are characterized as a set of asynchronous simulation applications each serving as both producers and consumers of shared state data. In terms of data aging characteristics, LVCs are found to be first-order linear systems. System performance is quantified via two opposing factors; the consistency of the distributed state space, and the response time or interaction quality of the autonomous simulation applications. A framework is developed that defines temporal data consistency requirements such that the objectives ...


A Physical Model Of Human Skin And Its Application For Search And Rescue, Abel S. Nunez Dec 2009

A Physical Model Of Human Skin And Its Application For Search And Rescue, Abel S. Nunez

Theses and Dissertations

For this research we created a human skin reflectance model in the VIS and NIR. We then modeled sensor output for an RGB sensor based on output from the skin reflectance model. The model was also used to create a skin detection algorithm and a skin pigmentation level (skin reflectance at 685nm) estimation algorithm. The average root mean square error across the VIS and NIR between the skin reflectance model and measured data was 2%. The skin reflectance model then allowed us to generate qualitatively accurate responses for an RGB sensor for different biological and lighting conditions. To test the ...


Graphene On Pt(111): Growth And Substrate Interaction, Peter Sutter, Jerzy T. Sadowski, Eli Sutter Dec 2009

Graphene On Pt(111): Growth And Substrate Interaction, Peter Sutter, Jerzy T. Sadowski, Eli Sutter

Faculty Publications from the Department of Electrical and Computer Engineering

In situ low-energy electron microscopy (LEEM) of graphene growth combined with measurements of the graphene structure and electronic band structure has been used to study graphene on Pt (111). Growth by carbon segregation produces macroscopic monolayer graphene domains extending continuously across Pt (111) substrate steps and bounded by strongly faceted edges. LEEM during cooling from the growth temperature shows the propagation of wrinkles in the graphene sheet, driven by thermal stress. The lattice mismatch between graphene and Pt (111) is accommodated by moiré structures with a large number of different rotational variants, without a clear preference for a particular interface ...


Egoviz – A Mobile Based Spatial Interaction System, Keith Gardiner, Junjun Yin, James Carswell Dec 2009

Egoviz – A Mobile Based Spatial Interaction System, Keith Gardiner, Junjun Yin, James Carswell

Articles

This paper describes research carried out in the area of mobile spatial interaction and the development of a mobile (i.e. on-device) version of a simulated web-based 2D directional query processor. The TellMe application integrates location (from GPS, GSM, WiFi) and orientation (from digital compass/tilt sensors) sensing technologies into an enhanced spatial query processing module capable of exploiting a mobile device’s position and orientation for querying real-world 3D spatial datasets. This paper outlines the technique used to combine these technologies and the architecture needed to deploy them on a sensor enabled smartphone (i.e. Nokia 6210 Navigator). With ...


Quality-Driven Cross Layer Design For Multimedia Security Over Resource Constrained Wireless Sensor Networks, Wei Wang Dec 2009

Quality-Driven Cross Layer Design For Multimedia Security Over Resource Constrained Wireless Sensor Networks, Wei Wang

Theses, Dissertations, & Student Research in Computer Electronics & Engineering

The strong need for security guarantee, e.g., integrity and authenticity, as well as privacy and confidentiality in wireless multimedia services has driven the development of an emerging research area in low cost Wireless Multimedia Sensor Networks (WMSNs). Unfortunately, those conventional encryption and authentication techniques cannot be applied directly to WMSNs due to inborn challenges such as extremely limited energy, computing and bandwidth resources. This dissertation provides a quality-driven security design and resource allocation framework for WMSNs. The contribution of this dissertation bridges the inter-disciplinary research gap between high layer multimedia signal processing and low layer computer networking. It formulates ...


Biological Sequence Simulation For Testing Complex Evolutionary Hypotheses: Indel-Seq-Gen Version 2.0, Cory L. Strope Dec 2009

Biological Sequence Simulation For Testing Complex Evolutionary Hypotheses: Indel-Seq-Gen Version 2.0, Cory L. Strope

Computer Science and Engineering: Theses, Dissertations, and Student Research

Reconstructing the evolutionary history of biological sequences will provide a better understanding of mechanisms of sequence divergence and functional evolution. Long-term sequence evolution includes not only substitutions of residues but also more dynamic changes such as insertion, deletion, and long-range rearrangements. Such dynamic changes make reconstructing sequence evolution history difficult and affect the accuracy of molecular evolutionary methods, such as multiple sequence alignments (MSAs) and phylogenetic methods. In order to test the accuracy of these methods, benchmark datasets are required. However, currently available benchmark datasets have limitations in their sizes and evolutionary histories of the included sequences are unknown. These ...


Anaglym: A Graphics Engine Providing Secure Execution Of Applications, Josh Holtrop Dec 2009

Anaglym: A Graphics Engine Providing Secure Execution Of Applications, Josh Holtrop

Masters Projects

"The Anaglym graphics engine uses the Lua programming language as the high-level language in which to interpret Anaglym applications. Applications running inside Anaglym are Lua scripts that have a particular environment exposed to them. By default, when Lua is embedded inside a C or C++ host application, no Lua functions are available to the hosted script. Lua functions must be exported by the host environment to be callable by a Lua script."


Convexity Bias In Eurodollar Futures Prices: A Dimension-Free Hjm Criterion, Vladimir Pozdnyakov, John M. Steele Dec 2009

Convexity Bias In Eurodollar Futures Prices: A Dimension-Free Hjm Criterion, Vladimir Pozdnyakov, John M. Steele

Operations, Information and Decisions Papers

In the theory of interest rate futures, the difference between the futures rate and forward rate is called the “convexity bias,” and there are several widely offered reasons why the convexity bias should be positive. Nevertheless, it is not infrequent that the empirical the bias is observed to be negative. Moreover, in its most general form, the benchmark Heath–Jarrow–Morton (HJM) term structure model is agnostic on the question of the sign of the bias; it allows for models where the convexity bias can be positive or negative. In partial support of the practitioner’s arguments, we develop a ...


Towards Optimal Effort Distribution In Process Design Under Uncertainty, With Application To Education, Olga Kosheleva, Vladik Kreinovich Dec 2009

Towards Optimal Effort Distribution In Process Design Under Uncertainty, With Application To Education, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

In most application areas, we need to take care of several (reasonably independent) participants. For example, in controlling economics, we must make sure that all the economic regions prosper. In controlling environment, we want to guarantee that all the geographic regions have healthy environment. In education, we want to make sure that all the students learn all the needed knowledge and skills.

In real life, the amount of resources is limited, so we face the problem of "optimally" distributing these resources between different objects.

What is a reasonable way to formalize "optimally"? For each of the participants, preferences can be ...


Optimal Sensor Placement In Environmental Research: Designing A Sensor Network Under Uncertainty, Aline James, Craig Tweedie, Tanja Magoc, Vladik Kreinovich, Martine Ceberio Dec 2009

Optimal Sensor Placement In Environmental Research: Designing A Sensor Network Under Uncertainty, Aline James, Craig Tweedie, Tanja Magoc, Vladik Kreinovich, Martine Ceberio

Departmental Technical Reports (CS)

One of our main challenges in meteorology and environment research is that in many important remote areas, sensor coverage is sparse, leaving us with numerous blind spots. Placement and maintenance of sensors in these areas are expensive. It is therefore desirable to find out how, within a given budget, we can design a sensor network are important activities was developing reasonable techniques for sensor that would provide us with the largest amount of useful information while minimizing the size of the "blind spot" areas which is not covered by the sensors.

This problem is very difficult even to formulate in ...


Symmetries: A General Approach To Integrated Uncertainty Management, Vladik Kreinovich, Hung T. Nguyen, Songsak Sriboonchitta Dec 2009

Symmetries: A General Approach To Integrated Uncertainty Management, Vladik Kreinovich, Hung T. Nguyen, Songsak Sriboonchitta

Departmental Technical Reports (CS)

We propose to use symmetries as a general approach to maintaining different types of uncertainty, and we show how the symmetry approach can help, especially in in economics-related applications.


Checking Design Constraints At Run-Time Using Ocl And Aspectj, Yoonsik Cheon, Carmen Avila, Steve Roach, Cuauhtemoc Munoz Dec 2009

Checking Design Constraints At Run-Time Using Ocl And Aspectj, Yoonsik Cheon, Carmen Avila, Steve Roach, Cuauhtemoc Munoz

Departmental Technical Reports (CS)

Design decisions and constraints of a software system can be specified precisely using a formal notation such as the Object Constraint Language (OCL). However, they are not executable, and assuring the conformance of an implementation to its design is hard. The inability of expressing design constraints in an implementation and checking them at runtime invites, among others, the problem of design drift and corrosion. We propose runtime checks as a solution to mitigate this problem. The key idea of our approach is to translate design constraints written in a formal notation such as OCL into aspects that, when applied to ...


An Efficient Time-Bound Hierarchical Key Assignment Scheme With A New Merge Function: A Performance Study, Rajasree Shyam Dec 2009

An Efficient Time-Bound Hierarchical Key Assignment Scheme With A New Merge Function: A Performance Study, Rajasree Shyam

Computer Science Graduate Projects and Theses

The advent of digital age has resulted in more television consumers switching to Digital TV with considerable improvement in image quality and ease-of-use. Consumers are able to select and view television programs and channels of choice by using a pay-per-use model or streaming video from their computer terminals. In all these use cases, the media provider requires a means by which they can restrict the consumers from watching selected programs for a pre-approved temporal interval. The consumer needs to be prevented access to certain pay-per-use channels and programs upon expiry of this pre-approved access. This necessitates the media provider to ...


Cyber Influence, William Hutchinson Dec 2009

Cyber Influence, William Hutchinson

Australian Information Warfare and Security Conference

This paper explores influence in the cyber-world and the ability and effectiveness of influence campaigns in this medium. It examines the possibilities of influence in the online world as examines the potential of mobile technologies in this area. The contentious link between influence and behavioural change is investigated. Counterinfluence in the context of radicalisation is also looked at. Whilst it is inevitable that the digital medium is and will be used for influence campaigns and will be influential regardless if there are concerted ‘campaigns’ or not, it effects in terms of behavioural change are still open to question.


Discrete Taylor Series As A Simple Way To Predict Properties Of Chemical Substances Like Benzenes And Cubanes, Jaime Nava, Vladik Kreinovich, Guillermo Restrepo, Douglas J. Klein Dec 2009

Discrete Taylor Series As A Simple Way To Predict Properties Of Chemical Substances Like Benzenes And Cubanes, Jaime Nava, Vladik Kreinovich, Guillermo Restrepo, Douglas J. Klein

Departmental Technical Reports (CS)

In many applications, we have numerous molecules that are obtained from a "template" molecule like benzene C6H6 or cubane C8H8 by replacing some of its hydrogen atoms with other atoms or atom groups (called ligands). Depending on how many original atoms are replaced and which ones are replaced, we obtain a large number of different chemical substances. It is desirable to be able, based on the measurements performed on a small number of such substances, to accurately predict the characteristics (such as energy) of all similar substances.

Such predictions are very important, since, e.g. cubanes, while kinetically stable, are ...


Fuzzy Transforms Of Higher Order Approximate Derivatives: A Theorem, Irina Perfilieva, Vladik Kreinovich Dec 2009

Fuzzy Transforms Of Higher Order Approximate Derivatives: A Theorem, Irina Perfilieva, Vladik Kreinovich

Departmental Technical Reports (CS)

In many practical applications, it is useful to represent a function f(x) by its fuzzy transform, i.e., by the "average" values over different elements of a fuzzy partition A1(x), ..., n(x) (for which Ai(x) >= 0 and A1(x) + ... + An(x) = 1). It is known that when we increase the number n of the partition elements Ai(x), the resulting approximation get closer and closer to the original function: for each value x0, the values Fi corresponding to the function Ai(x) for which Ai(x0) > 0 ...


Appraising Critical Infrastructure Systems With Visualisation, Graeme Pye, Matthew Warren Dec 2009

Appraising Critical Infrastructure Systems With Visualisation, Graeme Pye, Matthew Warren

Australian Information Warfare and Security Conference

This paper explores the use of system modelling as an approach for appraising critical infrastructure systems. It reports on focus group findings with relation to the system modelling aspects of a critical infrastructure security analysis and modelling framework. Specifically, this discussion focuses on the interpretations of a focus group in terms of the likely benefits or otherwise of system visualisation. With the group focusing on its perceived value as an educational tool in terms of providing an abstract visualisation representation of a critical infrastructure system incident.


Safeguarding Australia From Cyber-Terrorism:A Proposed Cyber-Terrorism Scada Risk Framework For Industry Adoption, Christopher Beggs, Matthew Warren Dec 2009

Safeguarding Australia From Cyber-Terrorism:A Proposed Cyber-Terrorism Scada Risk Framework For Industry Adoption, Christopher Beggs, Matthew Warren

Australian Information Warfare and Security Conference

Terrorist groups are currently using information and communication technologies (ICTs) to orchestrate their conventional physical attacks. More recently, terrorists have been developing a new form of capability within the cyber-arena to coordinate cyber-based attacks. This paper identifies that cyber-terrorism capabilities are an integral, imperative, yet under-researched component in establishing, and enhancing cyber-terrorism risk assessment models for SCADA systems. This paper is an extension of work previously published by Beggs and Warren 2008, it presents a high level overview of a cyber-terrorism SCADA risk framework that has been adopted and validated by SCADA industry practitioners. The paper proposes a managerial framework ...


Multiprocessor Real-Time Scheduling Considering Concurrency And Urgency, Jinkyu Lee, Arvind Easwaran, Insik Shin, Insup Lee Dec 2009

Multiprocessor Real-Time Scheduling Considering Concurrency And Urgency, Jinkyu Lee, Arvind Easwaran, Insik Shin, Insup Lee

Departmental Papers (CIS)

It has been widely studied how to schedule real-time tasks on multiprocessor platforms. Several studies find optimal scheduling policies for implicit deadline task systems, but it is hard to understand how each policy utilizes the two important aspects of scheduling real-time tasks on multiprocessors: inter-job concurrency and job urgency. In this paper, we introduce a new scheduling policy that considers these two properties. We prove that the policy is optimal for the special case when the execution time of all tasks are equally one and deadlines are implicit, and observe that the policy is a new concept in that it ...


Redesigning Src2pkg, A Linux Package Creation Toolkit, Timothy Goya Dec 2009

Redesigning Src2pkg, A Linux Package Creation Toolkit, Timothy Goya

Computer Science and Software Engineering

Package managers ease installation and removal of applications. However, as the name indicates, in order for a package manager to be useful, they need packages created from upstream sources to manage. This is the purpose of src2pkg, a toolkit written in Bash shell script which automates many package creation tasks. src2pkg, however, suffers from major design flaws that cripple its ability to package some exotic upstream sources. src2pkg-ng is a prototype redesign of src2pkg that eliminates these flaws. src2pkg-ng fully supports creating packages for Slackware and Slackware-compatible variants for at least 21 upstream sources with various levels of complexity. Debian ...


A Bandwidth Aware Modification To The Dsr Routing Protocol For Wireless Mesh Networks, Mustafa Ramadhan, Mark Davis Dec 2009

A Bandwidth Aware Modification To The Dsr Routing Protocol For Wireless Mesh Networks, Mustafa Ramadhan, Mark Davis

Conference papers

This work proposes a bandwidth aware cross-layer modification to the DSR routing protocol. We include the Access Efficiency Factor (AEF) parameter in addition to the hop-count in the routing discovery mechanism. AEF is a measure to the local availability of bandwidth at a node. Employing the AEF as a metric in the routing discovery mechanism attempts to avoid routing through a congested area in the network. In this modification, we impose a limit on the hop-count in order to control the delay time in the network. The path selection procedure operates by finding a path with the highest minimum AEF ...


The Convergence Of Broadcasting And Telephony: Legal And Regulatory Implications, Christopher S. Yoo Dec 2009

The Convergence Of Broadcasting And Telephony: Legal And Regulatory Implications, Christopher S. Yoo

Faculty Scholarship at Penn Law

This article, written for the inaugural issue of a new journal, analyzes the extent to which the convergence of broadcasting and telephony induced by the digitization of communications technologies is forcing policymakers to rethink their basic approach to regulating these industries. Now that voice and video are becoming available through every transmission technology, policymakers can no longer define the scope of regulatory obligations in terms of the mode of transmission. In addition, jurisdictions that employ separate agencies to regulate broadcasting and telephony must reform their institutional structures to bring both within the ambit of a single regulatory agency. The emergence ...


Vision-Based Reinforcement Learning Using A Consolidated Actor-Critic Model, Christopher Allen Niedzwiedz Dec 2009

Vision-Based Reinforcement Learning Using A Consolidated Actor-Critic Model, Christopher Allen Niedzwiedz

Masters Theses

Vision-based machine learning agents are tasked with making decisions based on high-dimensional, noisy input, placing a heavy load on available resources. Moreover, observations typically provide only partial information with respect to the environment state, necessitating robust state inference by the agent. Reinforcement learning provides a framework for decision making with the goal of maximizing long-term reward. This thesis introduces a novel approach to vision-based reinforce- ment learning through the use of a consolidated actor-critic model (CACM). The approach takes advantage of artificial neural networks as non-linear function approximators and the reduced com- putational requirements of the CACM scheme to yield ...