Computer Engineering Commons^™

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 …

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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 …

Digital Forensics And The Law, Karon N. Murff, Hugh E. Gardenier, Martha L. Gardenier

Annual ADFSL Conference on Digital Forensics, Security and Law

As computers and digital devices become more entrenched in our way of life, they become tools for both good and nefarious purposes. When the digital world collides with the legal world, a vast chasm is created. This paper will reflect how the legal community is failing to meet its obligation to provide adequate representation due to a lack of education about digital (computer) forensics. Whether in a civil litigation setting or a criminal setting, attorneys, prosecutors and judges have inadequate knowledge when it comes to the important questions they need to ask regarding digital evidence. Reliance on expert witnesses is …

Campus Grids: A Framework To Facilitate Resource Sharing, Derek J. Weitzel

School of Computing: Dissertations, Theses, and Student Research

It is common at research institutions to maintain multiple clusters. These might fulfill different needs and policies, or represent different owners or generations of hard- ware. Many of these clusters are under utilized while researchers at other departments may require these resources. This may be solved by linking clusters with grid mid- dleware. This thesis describes a distributed high throughput computing framework to link clusters without changing security or execution environments. The framework initially keeps jobs local to the submitter, overflowing if necessary to the campus, and regional grid. The framework is implemented spanning two campuses at the Holland Computing …

A Relativistic Enhancement To Software Transactional Memory, Philip William Howard, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Relativistic Programming is a technique that allows low overhead, linearly-scalable concurrent reads. It also allows joint access parallelism between readers and a writer. Unfortunately, it has so far been limited to a single writer so it does not scale on the write side. Software Transactional Memory (STM) is a technique that allows programs to take advantage of disjoint access parallelism on both the read-side and write-side. Unfortunately, STM systems have a higher overhead than many other synchronization mechanisms so although STM scales, STM starts from a lower baseline. We propose combining relativistic programming and software transactional memory in a way …

Protein Structure-Based Method For Identification Of Horizontal Gene Transfer In Bacteria, Swetha Billa

School of Computing: Dissertations, Theses, and Student Research

Horizontal Gene Transfer is defined as the movement of genetic material from one strain of species to another. Bacteria, being an asexual organism were always believed to transfer genes vertically. But recent studies provide evidence that shows bacteria can also transfer genes horizontally.

HGT plays a major role in evolution and medicine. It is the major contributor in bacterial evolution, enabling species to acquire genes to adapt to the new environments. Bacteria are also believed to develop drug resistance to antibiotics through the phenomenon of HGT. Therefore further study of HGT and its implications is necessary to understand the effects …

Design And Performance Analysis Of Mac Schemes For Wireless Sensor Networks Powered By Ambient Energy Harvesting, Zhi Ang Eu, Hwee-Pink Tan, Winston K. G. Seah

Research Collection School Of Computing and Information Systems

Energy consumption is a perennial issue in the design of wireless sensor networks (WSNs) which typically rely on portable sources like batteries for power. Recent advances in ambient energy harvesting technology have made it a potential and promising alternative source of energy for powering WSNs. By using energy harvesters with supercapacitors, WSNs are able to operate perpetually until hardware failure and in places where batteries are hard or impossible to replace. In this paper, we study the performance of different medium access control (MAC) schemes based on CSMA and polling techniques for WSNs which are solely powered by ambient energy …

Ontology For Psychophysiological Dysregulation Of Anger/Aggression, Swathi Vasanthapuram

School of Computing: Dissertations, Theses, and Student Research

The advancement of Information Technology in the last four decades led to the use of computers in medicine. A new area called Medical Informatics has emerged. This area comprises the application of IT to healthcare with the aim of creating tools that help healthcare personnel diagnose and treat patients more accurately and efficiently. IT not only provides tools for storing, integrating, and updating patient information base but also for processing information efficiently. One of such tools is a Clinical Decision Support System. Ontologies are an integral part of clinical decision support systems because they help formalize and integrate domain knowledge. …

Understanding User Generated Content Characteristics : A Hot-Event Perspective, Miao Wang, Guodong Li, Jie Feng, Lisong Xu, Byrav Ramamurthy, Wei Li, Xiaohong Guan

School of Computing: Conference and Workshop Papers

Nowadays, millions of Internet users watch and upload a large number of videos on User Generated Content (UGC) sites (e.g., Youtube) everyday. Moreover, online videos about hot events, such as breaking news and Olympic games, attract lots of users. In this paper, we study the characteristics of hot-event videos by collecting video traces of the largest UGC site in China for 28 days. We first empirically study statistical properties of such videos and find that hot-event videos contribute a large number of views, even though the total number of hotevent videos is relatively small. In addition, there exist extremely active …

A Cost-Benefit Analysis Of A Campus Computing Grid, Preston M. Smith

Purdue Polytechnic Masters Theses

Any major research institution has a substantial number of computer systems on its campus, often in the scale of tens of thousands. Given that a large amount of scientific computing is appropriate for execution in an opportunistic environment, a campus grid is an inexpensive way to build a powerful computational resource. What is missing, though, is a model for making an informed decision on the cost-effectives of a campus grid. In this thesis, the author describes a model for measuring the costs and benefits of building a campus computing resource based on the institution’s existing investment in computing hardware.

For …

Multi-Channel Peer-To-Peer Streaming Systems As Resource Allocation Problems, Miao Wang

School of Computing: Dissertations, Theses, and Student Research

In the past few years, the Internet has witnessed the success of Peer-to-Peer (P2P) streaming technology, which has attracted millions of users. More recently, commercial P2P streaming systems have begun to support multiple channels and a user in such systems is allowed to watch more than one channel at a time. We refer to such systems as multi-channel P2P streaming systems. In this dissertation, we focus on designing multi-channel P2P streaming systems with the goal of providing optimal streaming quality for all channels, termed as system-wide optimal streaming quality. Specifically, we design the systems from the perspective of how to …

Offline Optimization Of Advance Reservation Of Bandwidth Over Dynamic Circuit Networks, Pragatheeswaran Angu

School of Computing: Dissertations, Theses, and Student Research

E-science projects require very high-speed and reliable networks to transfer data across various destinations in the world. Dynamic Circuit Network (DCN) is a networking service to make advance reservation of bandwidth between a source and a destination in a network. In this thesis we solve the problem of advance reservation of bandwidth in next-generation wavelength-division multiplexing (WDM) networks using a simulation based approach.
We implement a greedy algorithm and a genetic algorithm in parallel, in separate threads. The request for advance reservation is processed by both but the user gets the response only from the greedy algorithm. The genetic algorithm …

Interactivity-Constrained Server Provisioning In Large-Scale Distributed Virtual Environments, Nguyen Binh Duong Ta, Thang Nguyen, Suiping Zhou, Xueyan Tang, Wentong Cai, Rassul Ayani

Research Collection School Of Computing and Information Systems

Maintaining interactivity is one of the key challenges in distributed virtual environments (DVE), e.g., online games, distributed simulations, etc., due to the large, heterogeneous Internet latencies; and the fact that clients in a DVE are usually geographically separated. In this paper, we consider a new problem, termed the interactivity-constrained server provisioning problem, whose goal is to minimize the number of distributed servers needed to achieve a pre-determined level of interactivity. We identify and formulate two variants of this new problem and show that they are both NP-hard via reductions to the set covering problem. We then propose several computationally efficient …

Polygonal Spatial Clustering, Deepti Joshi

School of Computing: Dissertations, Theses, and Student Research

Clustering, the process of grouping together similar objects, is a fundamental task in data mining to help perform knowledge discovery in large datasets.  With the growing number of sensor networks, geospatial satellites, global positioning devices, and human networks tremendous amounts of spatio-temporal data that measure the state of the planet Earth are being collected every day.  This large amount of spatio-temporal data has increased the need for efficient spatial data mining techniques.  Furthermore, most of the anthropogenic objects in space are represented using polygons, for example – counties, census tracts, and watersheds.  Therefore, it is important to develop data mining …

Cs 340: Programming Language Workshop In Python, Krishnaprasad Thirunarayan

Computer Science & Engineering Syllabi

This course is designed as a self-study in Python. You are expected to learn the language and solve a set of programming problems assigned to you from Budd's text using Python available from http://www.python.org. There are no exams. We officially meet only once in the quarter. However, I will be available in the posted office hours for clarifications and discussions about the programming problems.