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Articles 13231 - 13260 of 17325

Full-Text Articles in Computer Sciences

Message-Passing Algorithms For Quadratic Programming Formulations Of Map Estimation, Akshat Kumar, Shlomo Zilberstein Jul 2011

Message-Passing Algorithms For Quadratic Programming Formulations Of Map Estimation, Akshat Kumar, Shlomo Zilberstein

Research Collection School Of Computing and Information Systems

Computing maximum a posteriori (MAP) estimation in graphical models is an important inference problem with many applications. We present message-passing algorithms for quadratic programming (QP) formulations of MAP estimation for pairwise Markov random fields. In particular, we use the concave-convex procedure (CCCP) to obtain a locally optimal algorithm for the non-convex QP formulation. A similar technique is used to derive a globally convergent algorithm for the convex QP relaxation of MAP. We also show that a recently developed expectation-maximization (EM) algorithm for the QP formulation of MAP can be derived from the CCCP perspective. Experiments on synthetic and real-world problems …


A Hybrid Agent Architecture Integrating Desire, Intention And Reinforcement Learning, Ah-Hwee Tan, Yew-Soon Ong, Akejariyawong Tapanuj Jul 2011

A Hybrid Agent Architecture Integrating Desire, Intention And Reinforcement Learning, Ah-Hwee Tan, Yew-Soon Ong, Akejariyawong Tapanuj

Research Collection School Of Computing and Information Systems

This paper presents a hybrid agent architecture that integrates the behaviours of BDI agents, specifically desire and intention, with a neural network based reinforcement learner known as Temporal DifferenceFusion Architecture for Learning and COgNition (TD-FALCON). With the explicit maintenance of goals, the agent performs reinforcement learning with the awareness of its objectives instead of relying on external reinforcement signals. More importantly, the intention module equips the hybrid architecture with deliberative planning capabilities, enabling the agent to purposefully maintain an agenda of actions to perform and reducing the need of constantly sensing the environment. Through reinforcement learning, plans can also be …


A Framework For Dynamic Traffic Monitoring Using Vehicular Ad-Hoc Networks, Mohammad Hadi Arbabi Jul 2011

A Framework For Dynamic Traffic Monitoring Using Vehicular Ad-Hoc Networks, Mohammad Hadi Arbabi

Computer Science Theses & Dissertations

Traffic management centers (TMCs) need high-quality data regarding the status of roadways for monitoring and delivering up-to-date traffic conditions to the traveling public. Currently this data is measured at static points on the roadway using technologies that have significant maintenance requirements. To obtain an accurate picture of traffic on any road section at any time requires a real-time probe of vehicles traveling in that section. We envision a near-term future where network communication devices are commonly included in new vehicles. These devices will allow vehicles to form vehicular networks allowing communication among themselves, other vehicles, and roadside units (RSUs) to …


Localization Of Objects Using Stochastic Tunneling, Mohammed Rana Basheer, Sarangapani Jagannathan Jun 2011

Localization Of Objects Using Stochastic Tunneling, Mohammed Rana Basheer, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a novel wireless localization scheme in the three-dimensional domain that employs stochastic optimization with tunneling transformation to recursively estimate the location of wireless tags in a network from pair wise signal strength measurements. Spatially co-located wireless tags, receiving signals from a common transmitter, exhibit correlation in their Received Signal Strength Indicator (RSSI) values. Hence in a network of wireless tags, with pair wise correlation coefficients available, posterior distribution of the unknown tag separation is used to relatively localize them using maximum a posteriori (MAP) Estimator. However, due to the non-convex/non-tractable nature of this posterior distribution, deterministic optimization …


Numerical Modeling Of The Cn Spectral Emission Of The Stardust Re-Entry Vehicle, Alexandre Martin, Erin D. Farbar, Iain D. Boyd Jun 2011

Numerical Modeling Of The Cn Spectral Emission Of The Stardust Re-Entry Vehicle, Alexandre Martin, Erin D. Farbar, Iain D. Boyd

Mechanical Engineering Faculty Publications

Re-entry vehicles designed for space exploration are usually equipped with thermal protection systems made of ablative material. In order to properly model and predict the aerothermal environment of the vehicle, it is imperative to account for the gases produced by ablation processes. In the case of charring ablators, where an inner resin is pyrolyzed at a relatively low temperature, the composition of the gas expelled into the boundary layer is complex and may lead to thermal chemical reactions that cannot be captured with simple ow chemistry models. In order to obtain better predictions, an appropriate gas ow chemistry model needs …


Multi-Field Visualization For Biomedical Data Sets, Thomas Wischgoll Jun 2011

Multi-Field Visualization For Biomedical Data Sets, Thomas Wischgoll

Computer Science and Engineering Faculty Publications

No abstract provided.


Resizable, Scalable, Concurrent Hash Tables Via Relativistic Programming, Josh Triplett, Paul E. Mckenney, Jonathan Walpole Jun 2011

Resizable, Scalable, Concurrent Hash Tables Via Relativistic Programming, Josh Triplett, Paul E. Mckenney, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Presentation focusing on software synchronization, thread locking, transactional memory, and relativistic programming. Hash table algorithms are presented with examples of relativistic list insertion and removal, and related data structures. Existing approaches are compared to new methodologies and future work with relativistic data structures.


Resizable, Scalable, Concurrent Hash Tables, Josh Triplett, Paul E. Mckenney, Jonathan Walpole Jun 2011

Resizable, Scalable, Concurrent Hash Tables, Josh Triplett, Paul E. Mckenney, Jonathan Walpole

Computer Science Faculty Publications and Presentations

We present algorithms for shrinking and expanding a hash table while allowing concurrent, wait-free, linearly scalable lookups. These resize algorithms allow the hash table to maintain constant-time performance as the number of entries grows, and reclaim memory as the number of entries decreases, without delaying or disrupting readers.

We implemented our algorithms in the Linux kernel, to test their performance and scalability. Benchmarks show lookup scalability improved 125x over readerwriter locking, and 56% over the current state-of-the-art for Linux, with no performance degradation for lookups during a resize.

To achieve this performance, this hash table implementation uses a new concurrent …


Work In Progress: Vortex Detection And Visualization For Design Of Micro Air Vehicles And Turbomachinery, Rhonda J. Vickery, Thomas Wischgoll, Christopher Koehler, Matthew Pickett, Neal Eikenberry, Lance Harris, Richard E. Snyder, Darius Sanders, Haibo Dong, Randall Hand, Hugh Thornburg Jun 2011

Work In Progress: Vortex Detection And Visualization For Design Of Micro Air Vehicles And Turbomachinery, Rhonda J. Vickery, Thomas Wischgoll, Christopher Koehler, Matthew Pickett, Neal Eikenberry, Lance Harris, Richard E. Snyder, Darius Sanders, Haibo Dong, Randall Hand, Hugh Thornburg

Computer Science and Engineering Faculty Publications

No abstract provided.


Android Application Controlled Surge Protector, Lok An Jun 2011

Android Application Controlled Surge Protector, Lok An

Electrical Engineering

A significant amount of consumer electronics cannot be switched off completely without being unplugged. Standby power, also known as phantom power, refers to the electric power consumed by electronic appliances when they are switched off. There are some devices that need constant power; items like alarm clocks and security systems need constant power to function correctly. Some devices, such as video game consoles and televisions, consume power without offering any features. Electricity lost from standby power has been increasing with the amount of consumer electronics increasing in households.

This project’s goal is to create a low power remote that can …


Wolf Ant, Gilbert L. Peterson, Christopher M. Mayer, Kevin Cousin Jun 2011

Wolf Ant, Gilbert L. Peterson, Christopher M. Mayer, Kevin Cousin

Faculty Publications

Ant colony optimization (ACO) algorithms can generate quality solutions to combinatorial optimization problems. However, like many stochastic algorithms, the quality of solutions worsen as problem sizes grow. In an effort to increase performance, we added the variable step size off-policy hill-climbing algorithm called PDWoLF (Policy Dynamics Win or Learn Fast) to several ant colony algorithms: Ant System, Ant Colony System, Elitist-Ant System, Rank-based Ant System, and Max-Min Ant System. Easily integrated into each ACO algorithm, the PDWoLF component maintains a set of policies separate from the ant colony's pheromone. Similar to pheromone but with different update rules, the PDWoLF policies …


A Feature Based Frequency Domain Analysis Algorithm For Fault Detection Of Induction Motors, Zhaoxia Wang, C. S. Chang, Zhang Yifan Jun 2011

A Feature Based Frequency Domain Analysis Algorithm For Fault Detection Of Induction Motors, Zhaoxia Wang, C. S. Chang, Zhang Yifan

Research Collection School Of Computing and Information Systems

This paper studies the stator currents collected from several inverter-fed laboratory induction motors and proposes a new feature based frequency domain analysis method for performing the detection of induction motor faults, such as the broken rotor-bar or bearing fault. The mathematical formulation is presented to calculate the features, which are called FFT-ICA features in this paper. The obtained FFT-ICA features are normalized by using healthy motor as benchmarks to establish a feature database for fault detection. Compare with conventional frequency-domain analysis method, no prior knowledge of the motor parameters or other measurements are required for calculating features. Only one phase …


Supervisory Evolutionary Optimization Strategy For Adaptive Maintenance Schedules, Zhaoxia Wang, C. S. Chang Jun 2011

Supervisory Evolutionary Optimization Strategy For Adaptive Maintenance Schedules, Zhaoxia Wang, C. S. Chang

Research Collection School Of Computing and Information Systems

No abstract provided.


Online Fault Detection Of Induction Motors Using Frequency Domain Independent Components Analysis, Zhaoxia Wang, C. S. Chang Jun 2011

Online Fault Detection Of Induction Motors Using Frequency Domain Independent Components Analysis, Zhaoxia Wang, C. S. Chang

Research Collection School Of Computing and Information Systems

This paper proposes an online fault detection method for induction motors using frequency-domain independent component analysis. Frequency-domain results, which are obtained by applying Fast Fourier Transform (FFT) to measured stator current time-domain waveforms, are analyzed with the aim of extracting frequency signatures of healthy and faulty motors with broken rotor-bar or bearing problem. Independent components analysis (ICA) is applied for such an aim to the FFT results. The obtained independent components as well as the FFT results are then used to obtain the combined fault signatures. The proposed method overcomes problems occurring in many existing FFT-based methods. Results using laboratory-collected …


Using Service Responsibility Tables To Supplement Uml In Analyzing E-Service Systems, Xin Tan, Steven Alter, Keng Siau Jun 2011

Using Service Responsibility Tables To Supplement Uml In Analyzing E-Service Systems, Xin Tan, Steven Alter, Keng Siau

Research Collection School Of Computing and Information Systems

This paper proposes using Service Responsibility Tables (SRTs) as a tool in analyzing e-service systems. First it discusses difficulties and deficiencies of using formal modeling languages such as UML in analyzing e-service systems. It proposes using SRTs as an informal language and lightweight analytical tool to be used by business professionals in analyzing e-service systems. SRTs are based on a service value chain framework but do not rely on abstract concepts and constructs, and therefore can be used by business professionals to supplement UML. We suggest a set of heuristics for transforming SRTs into two key UML diagrams, thereby illustrating …


Ios Mobile Device Forensics: Initial Analysis, Rita M. Barrios, Michael R. Lehrfeld May 2011

Ios Mobile Device Forensics: Initial Analysis, Rita M. Barrios, Michael R. Lehrfeld

Annual ADFSL Conference on Digital Forensics, Security and Law

The ability to recover forensic artifacts from mobile devices is proving to be an ever-increasing challenge for investigators. Coupling this with the ubiquity of mobile devices and the increasing complexity and processing power they contain results in a reliance on them by suspects. In investigating Apple’s iOS devices -- namely the iPhone and iPad -- an investigator’s challenges are increased due to the closed nature of the platforms. What is left is an extremely powerful and complex mobile tool that is inexpensive, small, and can be used in suspect activities. Little is known about the internal data structures of the …


Forensic Analysis Of Smartphones: The Android Data Extractor Lite (Adel), Felix Freiling, Michael Spreitzenbarth, Sven Schmitt May 2011

Forensic Analysis Of Smartphones: The Android Data Extractor Lite (Adel), Felix Freiling, Michael Spreitzenbarth, Sven Schmitt

Annual ADFSL Conference on Digital Forensics, Security and Law

Due to the ubiquitous use of smartphones, these devices become an increasingly important source of digital evidence in forensic investigations. Thus, the recovery of digital traces from smartphones often plays an essential role for the examination and clarification of the facts in a case. Although some tools already exist regarding the examination of smartphone data, there is still a strong demand to develop further methods and tools for forensic extraction and analysis of data that is stored on smartphones. In this paper we describe specifications of smartphones running Android. We further introduce a newly developed tool – called ADEL – …


Survey On Cloud Forensics And Critical Criteria For Cloud Forensic Capability: A Preliminary Analysis, Keyun Ruan, Ibrahim Baggili, Joe Carthy, Tahar Kechadi May 2011

Survey On Cloud Forensics And Critical Criteria For Cloud Forensic Capability: A Preliminary Analysis, Keyun Ruan, Ibrahim Baggili, Joe Carthy, Tahar Kechadi

Annual ADFSL Conference on Digital Forensics, Security and Law

In this paper we present the current results and analysis of the survey “Cloud forensics and critical criteria for cloud forensic capability” carried out towards digital forensic experts and practitioners. This survey was created in order to gain a better understanding on some of the key questions of the new field - cloud forensics - before further research and development. We aim to understand concepts such as its definition, the most challenging issues, most valuable research directions, and the critical criteria for cloud forensic capability.

Keywords: Cloud Forensics, Cloud Computing, Digital Forensics, Survey, Cloud Forensic Capability


Kindle Forensics: Acquisition & Analysis, Peter Hannay May 2011

Kindle Forensics: Acquisition & Analysis, Peter Hannay

Annual ADFSL Conference on Digital Forensics, Security and Law

The Amazon Kindle eBook reader supports a wide range of capabilities beyond reading books. This functionality includes an inbuilt cellular data connection known as Whispernet. The Kindle provides web browsing, an application framework, eBook delivery and other services over this connection. The historic data left by user interaction with this device may be of forensic interest. Analysis of the Amazon Kindle device has resulted in a method to reliably extract and interpret data from these devices in a forensically complete manner.

Keywords: forensics, digital forensics, kindle, mobile, embedded, ebook, ereader


Aacsb‐Accredited Schools’ Adoption Of Information Security Curriculum, Linda Lau, Cheryl Davis May 2011

Aacsb‐Accredited Schools’ Adoption Of Information Security Curriculum, Linda Lau, Cheryl Davis

Annual ADFSL Conference on Digital Forensics, Security and Law

The need to professionally and successfully conduct computer forensic investigations of incidents has never been greater. This has launched an increasing demand for a skilled computer security workforce (Locasto, et al., 2011). This paper examines the extent to which AACSB-accredited universities located in Virginia, Maryland and Washington, D.C. are working towards providing courses that will meet this demand. The authors conduct an online research of the information security courses and programs offered by the 27 AACSB-accredited business schools in the selected area.

The preliminary investigation revealed that eight of the 27 participating universities did not offer any courses in cybersecurity, …


Digital Forensics Investigation In A Collegiate Environment, Robert E. Johnston May 2011

Digital Forensics Investigation In A Collegiate Environment, Robert E. Johnston

Annual ADFSL Conference on Digital Forensics, Security and Law

Creating, building, managing a cost effective digital forensics lab including a team of qualified examiners can be a challenge for colleges [1] with multiple campuses in multiple towns, counties and states. Leaving such examination responsibilities to each of the campuses results in not only disparity in the results but more than likely excessive duplication of efforts as well as the potential for compromise of evidence. Centralizing the forensic efforts results in a team that is not subject to the political pressures of a campus and virtually eliminates the possibility of examiner favoritism. Learn what it takes to create a cost …


Backtrack In The Outback - A Preliminary Report On Cyber Security Evaluation Of Organisations In Western Australia, Craig Valli, Andrew Woodward, Peter Hannay May 2011

Backtrack In The Outback - A Preliminary Report On Cyber Security Evaluation Of Organisations In Western Australia, Craig Valli, Andrew Woodward, Peter Hannay

Annual ADFSL Conference on Digital Forensics, Security and Law

The authors were involved in extensive vulnerability assessment and penetration testing of over 15 large organisations across various industry sectors in the Perth CBD. The actual live testing involved a team of five people for approximately a four week period, and was black box testing. The scanning consisted of running network and web vulnerability tools, and in a few cases, exploiting vulnerability to establish validity of the tools. The tools were run in aggressive mode with no attempt made to deceive or avoid detection by IDS/IPS or firewalls. The aim of the testing was to determine firstly whether these organisations …


Creating Realistic Corpora For Security And Forensic Education, Kam Woods, Christopher A. Lee, Simson Garfinkel, David Dittrich, Adam Russell, Kris Kearton May 2011

Creating Realistic Corpora For Security And Forensic Education, Kam Woods, Christopher A. Lee, Simson Garfinkel, David Dittrich, Adam Russell, Kris Kearton

Annual ADFSL Conference on Digital Forensics, Security and Law

We present work on the design, implementation, distribution, and use of realistic forensic datasets to support digital forensics and security education. We describe in particular the “M57-Patents” scenario, a multi-modal corpus consisting of hard drive images, RAM images, network captures, and images from other devices typically found in forensics investigations such as USB drives and cellphones. Corpus creation has been performed as part of a scripted scenario; subsequently it is less “noisy” than real-world data but retains the complexity necessary to support a wide variety of forensic education activities. Realistic forensic corpora allow direct comparison of approaches and tools across …


Developing A Forensic Continuous Audit Model, Grover S. Kearns, Katherine J. Barker May 2011

Developing A Forensic Continuous Audit Model, Grover S. Kearns, Katherine J. Barker

Annual ADFSL Conference on Digital Forensics, Security and Law

Despite increased attention to internal controls and risk assessment, traditional audit approaches do not seem to be highly effective in uncovering the majority of frauds. Less than 20 percent of all occupational frauds are uncovered by auditors. Forensic accounting has recognized the need for automated approaches to fraud analysis yet research has not examined the benefits of forensic continuous auditing as a method to detect and deter corporate fraud. The purpose of this paper is to show how such an approach is possible. A model is presented that supports the acceptance of forensic continuous auditing by auditors and management as …


Development Of A Distributed Print‐Out Monitoring System For Efficient Forensic Investigation, Satoshi Kai, Tetsutaro Uehara May 2011

Development Of A Distributed Print‐Out Monitoring System For Efficient Forensic Investigation, Satoshi Kai, Tetsutaro Uehara

Annual ADFSL Conference on Digital Forensics, Security and Law

If information leakage occurs, an investigator is instructed to specify what documents were leaked and who leaked them. In the present work, a distributed print-out monitoring system—which consists of a virtual printer driver and print-out policy/log management servers—was developed. For easily matching the discovered (i.e., leaked) paper document with the print-out log, the virtual printer driver acquires full-text of printed-out documents by DDI hooking technique to check the content, transforms a spool file to a picture file and creates both a thumbnail and text log for forensic investigation afterwards. The log size is as only about 0.04 times bigger than …


Mac Os X Forensics: Password Discovery, David Primeaux, Robert Dahlberg, Kamnab Keo, Stephen Larson, B. Pennell, K. Sherman May 2011

Mac Os X Forensics: Password Discovery, David Primeaux, Robert Dahlberg, Kamnab Keo, Stephen Larson, B. Pennell, K. Sherman

Annual ADFSL Conference on Digital Forensics, Security and Law

OS X provides a password-rich environment in which passwords protect OS X resources and perhaps many other resources accessed through OS X. Every password an investigator discovers in an OS X environment has the potential for use in discovering other such passwords, and any discovered passwords may also be useful in other aspects of an investigation, not directly related to the OS X environment. This research advises the use of multiple attack vectors in approaching the password problem in an OS X system, including the more generally applicable non-OS X-specific techniques such as social engineering or well-known password cracking techniques …


Software Piracy Forensics: Impact And Implications Of Post‐Piracy Modifications, Vinod Bhattathiripad, S. Santhosh Baboo May 2011

Software Piracy Forensics: Impact And Implications Of Post‐Piracy Modifications, Vinod Bhattathiripad, S. Santhosh Baboo

Annual ADFSL Conference on Digital Forensics, Security and Law

Piracy is potentially possible at any stage of the lifetime of the software. In a post-piracy situation, however, the growth of the respective versions of the software (both the original and pirated) is expected to be in different directions as a result of expectedly different implementation strategies. This paper shows how such post-piracy modifications are of special interest to a cyber crime expert investigating software piracy and suggests that the present software piracy forensic (or software copyright infringement investigation) approaches require amendments to take in such modifications. For this purpose, the paper also presents a format that is jargon-free, so …


Understanding Issues In Cloud Forensics: Two Hypothetical Case Studies, Josiah Dykstra, Alan T. Sherman May 2011

Understanding Issues In Cloud Forensics: Two Hypothetical Case Studies, Josiah Dykstra, Alan T. Sherman

Annual ADFSL Conference on Digital Forensics, Security and Law

The inevitable vulnerabilities and criminal targeting of cloud environments demand an understanding of how digital forensic investigations of the cloud can be accomplished. We present two hypothetical case studies of cloud crimes; child pornography being hosted in the cloud, and a compromised cloudbased website. Our cases highlight shortcomings of current forensic practices and laws. We describe significant challenges with cloud forensics, including forensic acquisition, evidence preservation and chain of custody, and open problems for continued research.

Keywords: Cloud computing, cloud forensics, digital forensics, case studies


A Practitioners Guide To The Forensic Investigation Of Xbox 360 Gaming Consoles, Ashley L. Podhradsky, Rob D’Ovidio, Cindy Casey May 2011

A Practitioners Guide To The Forensic Investigation Of Xbox 360 Gaming Consoles, Ashley L. Podhradsky, Rob D’Ovidio, Cindy Casey

Annual ADFSL Conference on Digital Forensics, Security and Law

Given the ubiquitous nature of computing, individuals now have nearly 24-7 access to the internet. People are not just going online through traditional means with a PC anymore, they are now frequently using nontraditional devices such as cell phones, smart phones, and gaming consoles. Given the increased use of gaming consoles for online access, there is also an increased use of gaming consoles to commit criminal activity. The digital forensic community has been tasked with creating new approaches for forensically analyzing gaming consoles. In this research paper the authors demonstrate different tools, both commercial and open source, available to forensically …


Sampling: Making Electronic Discovery More Cost Effective, Milton Luoma, Vicki Luoma May 2011

Sampling: Making Electronic Discovery More Cost Effective, Milton Luoma, Vicki Luoma

Annual ADFSL Conference on Digital Forensics, Security and Law

With the huge volumes of electronic data subject to discovery in virtually every instance of litigation, time and costs of conducting discovery have become exceedingly important when litigants plan their discovery strategies. Rather than incurring the costs of having lawyers review every document produced in response to a discovery request in search of relevant evidence, a cost effective strategy for document review planning is to use statistical sampling of the database of documents to determine the likelihood of finding relevant evidence by reviewing additional documents. This paper reviews and discusses how sampling can be used to make document review more …