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Full-Text Articles in Computer Sciences

Numerical Methods For Fmri Data Analysis, Geethmala Sridaran Aug 2010

Numerical Methods For Fmri Data Analysis, Geethmala Sridaran

Dartmouth College Master’s Theses

Brain imaging data are increasingly analyzed via a range of machine-learning methods. In this thesis, we discuss three specific contributions to the field of neuroimaging analysis methods: 1. To apply a recently-developed technique for identifying and viewing similarity structure in neuroimaging data, in which candidate representational structures are ranked; 2. Provide side-by-side analyses of neuroimaging data by a typical non-hierarchical (SVM) versus hierarchical (Decision Tree) machine-learning classification methods; and 3. To develop a novel programming environment for PyMVPA, a current popular analysis toolbox, such that users will be able to type a small number of packaged commands to carry out …


Is Bluetooth The Right Technology For Mhealth?, Shrirang Mare, David Kotz Aug 2010

Is Bluetooth The Right Technology For Mhealth?, Shrirang Mare, David Kotz

Dartmouth Scholarship

Many people believe mobile healthcare (mHealth) would help alleviate the rising cost of healthcare and improve the quality of service. Bluetooth, which is the most popular wireless technology for personal medical devices, is used for most of the mHealth sensing applications. In this paper we raise the question – Is Bluetooth the right technology for mHealth? To instigate the discussion we discuss some shortcomings of Bluetooth and also point out an alternative solution.


On Usable Authentication For Wireless Body Area Networks, Cory Cornelius, David Kotz Aug 2010

On Usable Authentication For Wireless Body Area Networks, Cory Cornelius, David Kotz

Dartmouth Scholarship

We examine a specific security problem in wireless body area networks (WBANs), what we call the ıt one body authentication problem. That is, how can we ensure that the wireless sensors in a WBAN are collecting data about one individual and not several individuals. We explore existing solutions to this problem and provide some analysis why these solutions are inadequate. Finally, we provide some direction towards a promising solution to the problem and how it can be used to create a usably secure WBAN.


Virtual Container Attestation: Customized Trusted Containers For On-Demand Computing., Katelin A. Bailey Jun 2010

Virtual Container Attestation: Customized Trusted Containers For On-Demand Computing., Katelin A. Bailey

Dartmouth College Undergraduate Theses

In today's computing environment, data is moving to central locations and most computers are merely used to access the data. Today is the era of cloud computing and distributed computing, where users have control over neither data nor computation. As this trend continues there is an increasing frequency of mutually distrustful parties being forced to interact and share resources with each other in potentially dangerous situations. Therefore, there is an urgent need for a means of creating trust between two entities, or at the very least providing some means of determining the trust level of a given machine. Current approaches …


Creating Large Disturbances In The Power Grid: Methods Of Attack After Cyber Infiltration, Loren D. Sands-Ramshaw Jun 2010

Creating Large Disturbances In The Power Grid: Methods Of Attack After Cyber Infiltration, Loren D. Sands-Ramshaw

Dartmouth College Undergraduate Theses

Researchers are pursuing methods of securing the cyber aspect of the U.S. power grid, one of the country's most critical infrastructures. An attacker who is able to infiltrate an Energy Management System (EMS) can instruct elements of the grid to function improperly or can skew the state information received by the control programs or operators. In addition, a cyber attack can combine multiple attacks and affect many physical locations at once. A study of the possible adverse effects an attack could generate can underline the urgency of improving grid security, contribute to a roadmap and priority list for security researchers, …


Block Sensitivity Versus Sensitivity, Karn Seth Jun 2010

Block Sensitivity Versus Sensitivity, Karn Seth

Dartmouth College Undergraduate Theses

Sensitivity and block sensitivity are useful and well-studied measures of computational complexity, but in spite of their similarities, the largest possible gap between them is still unknown. Rubinstein showed that this gap must be at least quadratic, and Kenyon and Kutin showed that it is at worst exponential, but many strongly suspect that the gap is indeed quadratic, or at worst polynomial. Our work shows that for a large class of functions, which includes Rubinstein's function, the quadratic gap between sensitivity and block sensitivity is the best we can possibly do.


Predictive Yasir: High Security With Lower Latency In Legacy Scada, Rouslan V. Solomakhin Jun 2010

Predictive Yasir: High Security With Lower Latency In Legacy Scada, Rouslan V. Solomakhin

Dartmouth College Master’s Theses

Message authentication with low latency is necessary to ensure secure operations in legacy industrial control networks, such as power grid networks. Previous authentication solutions by our lab and others looked at single messages and incurred noticeable latency. To reduce this latency, we develop Predictive YASIR, a bump-in-the-wire device that looks at broader patterns of messages. The device (1) predicts the incoming plaintext based on previous observations; (2) compresses, encrypts, and authenticates data online; and (3) pre-sends a part of ciphertext before receiving the whole plaintext. I demonstrate the performance properties of this approach by implementing it in the Scalable Simulation …


Optimization Algorithms For Site-Directed Protein Recombination Experiment Planning, Wei Zheng Jun 2010

Optimization Algorithms For Site-Directed Protein Recombination Experiment Planning, Wei Zheng

Dartmouth College Ph.D Dissertations

Site-directed protein recombination produces improved and novel protein variants by recombining sequence fragments from parent proteins. The resulting hybrids accumulate multiple mutations that have been evolutionarily accepted together. Subsequent screening or selection identifies hybrids with desirable characteristics. In order to increase the "hit rate" of good variants, this thesis develops experiment planning algorithms to optimize protein recombination experiments. First, to improve the frequency of generating novel hybrids, a metric is developed to assess the diversity among hybrids and parent proteins. Dynamic programming algorithms are then created to optimize the selection of breakpoint locations according to this metric. Second, the trade-off …


Graph Algorithms For Nmr Resonance Assignment And Cross-Link Experiment Planning, Fei Xiong Jun 2010

Graph Algorithms For Nmr Resonance Assignment And Cross-Link Experiment Planning, Fei Xiong

Dartmouth College Ph.D Dissertations

The study of three-dimensional protein structures produces insights into protein function at the molecular level. Graphs provide a natural representation of protein structures and associated experimental data, and enable the development of graph algorithms to analyze the structures and data. This thesis develops such graph representations and algorithms for two novel applications: structure-based NMR resonance assignment and disulfide cross-link experiment planning for protein fold determination. The first application seeks to identify correspondences between spectral peaks in NMR data and backbone atoms in a structure (from x-ray crystallography or homology modeling), by computing correspondences between a contact graph representing the structure …


The Curious Timekeeper: Creative Thesis In Interactive Sculpture, Kate I. Schnippering May 2010

The Curious Timekeeper: Creative Thesis In Interactive Sculpture, Kate I. Schnippering

Dartmouth College Undergraduate Theses

When we interact with computers, we have set expectations about our interactive experience, operating a mouse and keyboard to elicit predictable responses on a screen. Intersecting the world of Computing with Fine Art gains us potential to innovate outside these bounds by restricting the expected performance of a computer-- setting it to a particular purpose rather than allowing it to run anyone's software. To challenge standard human-computer interaction, this work set out to create an interesting and unusual interactive experience, fully integrated into a sculpture. The approach was to design a system to form a small environment, having many components …


Neurophone: Brain-Mobile Phone Interface Using A Wireless Eeg Headset, Matthew K. Mukerjee May 2010

Neurophone: Brain-Mobile Phone Interface Using A Wireless Eeg Headset, Matthew K. Mukerjee

Dartmouth College Undergraduate Theses

Neural signals are everywhere just like mobile phones. We propose to use neural signals to control mobile phones for hands-free, silent and effortless human-mobile interaction. Until recently, devices for detecting neural signals have been costly, bulky and fragile. We present the design, implementation and evaluation of the NeuroPhone system, which allows neural signals to drive mobile phone applications on the iPhone using cheap off-the-shelf wireless electroencephalography (EEG) headsets. We demonstrate a mind-controlled address book dialing app, which works on similar principles to P300-speller brain-computer interfaces: the phone flashes a sequence of photos of contacts from the address book and a …


A 3-D Photo Forensic Analysis Of The Lee Harvey Oswald Backyard Photo, Hany Farid May 2010

A 3-D Photo Forensic Analysis Of The Lee Harvey Oswald Backyard Photo, Hany Farid

Computer Science Technical Reports

More than forty-five years after the assassination of U.S. President Kennedy theories continue to circulate suggesting that the accused assassin, Lee Harvey Oswald, acted as part of a larger conspiracy. It has been argued, for example, that incriminating photographs of Oswald were manipulated, and hence evidence of a broader plot. We describe a detailed 3-D analysis of the Oswald photos to determine if such claims of tampering are warranted.


A Note On Randomized Streaming Space Bounds For The Longest Increasing Subsequence Problem, Amit Chakrabarti May 2010

A Note On Randomized Streaming Space Bounds For The Longest Increasing Subsequence Problem, Amit Chakrabarti

Computer Science Technical Reports

The deterministic space complexity of approximating the length of the longest increasing subsequence of a stream of N integers is known to be Theta~(sqrt N). However, the randomized complexity is wide open. We show that the technique used in earlier work to establish the Omega(sqrt N) deterministic lower bound fails strongly under randomization: specifically, we show that the communication problems on which the lower bound is based have very efficient randomized protocols. The purpose of this note is to guide and alert future researchers working on this very interesting problem.


Saluki: A High-Performance Wi-Fi Sniffing Program, Keren Tan, David Kotz May 2010

Saluki: A High-Performance Wi-Fi Sniffing Program, Keren Tan, David Kotz

Dartmouth Scholarship

Building a campus-wide wireless LAN measurement system faces many efficiency, scalability and security challenges. To address these challenges, we developed a distributed Wi-Fi sniffing program called Saluki. Compared to our previous implementation and to other available sniffing programs, Saluki has the following advantages: (1) its small footprint makes it suitable for a resource-constrained Linux platform, such as those in commercial Wi-Fi access points; (2) the frame-capture rate increased more than three-fold over tcpdump with minimal frame loss; (3) all traffic between this sniffer and the back-end server was secured using 128-bit encryption; and (4) the traffic load on the backbone …


Information Cost Tradeoffs For Augmented Index And Streaming Language Recognition, Amit Chakrabarti, Graham Cormode, Ranganath Kondapally, Andrew Mcgregor Apr 2010

Information Cost Tradeoffs For Augmented Index And Streaming Language Recognition, Amit Chakrabarti, Graham Cormode, Ranganath Kondapally, Andrew Mcgregor

Dartmouth Scholarship

This paper makes three main contributions to the theory of communication complexity and stream computation. First, we present new bounds on the information complexity of AUGMENTED-INDEX. In contrast to analogous results for INDEX by Jain, Radhakrishnan and Sen [J. ACM, 2009], we have to overcome the significant technical challenge that protocols for AUGMENTED-INDEX may violate the “rectangle property” due to the inherent input sharing. Second, we use these bounds to resolve an open problem of Magniez, Mathieu and Nayak [STOC, 2010] that asked about the multi-pass complexity of recognizing Dyck languages. This results in a natural separation between the standard …


On The Reliability Of Wireless Fingerprinting Using Clock Skews, Chrisil Arackaparambil, Sergey Bratus, Anna Shubina, David Kotz Mar 2010

On The Reliability Of Wireless Fingerprinting Using Clock Skews, Chrisil Arackaparambil, Sergey Bratus, Anna Shubina, David Kotz

Dartmouth Scholarship

No abstract provided.


Constant Rmr Solutions To Reader Writer Synchronization, Vibhor Bhatt, Prasad Jayanti Feb 2010

Constant Rmr Solutions To Reader Writer Synchronization, Vibhor Bhatt, Prasad Jayanti

Computer Science Technical Reports

We study Reader-Writer Exclusion, a well-known variant of the Mutual Exclusion problem where processes are divided into two classes--readers and writers--and multiple readers can be in the Critical Section (CS) at the same time, although no process may be in the CS at the same time as a writer. Since readers don't conflict with each other, they should not obstruct each other. Specifically, the concurrent entering property must be satisfied: if all writers are in the remainder section, each reader should be able to enter the CS in a bounded number of its own steps. Three versions of the Reader-Writer …


Flexible Object Manipulation, Matthew P. Bell Feb 2010

Flexible Object Manipulation, Matthew P. Bell

Dartmouth College Ph.D Dissertations

Flexible objects are a challenge to manipulate. Their motions are hard to predict, and the high number of degrees of freedom makes sensing, control, and planning difficult. Additionally, they have more complex friction and contact issues than rigid bodies, and they may stretch and compress. In this thesis, I explore two major types of flexible materials: cloth and string. For rigid bodies, one of the most basic problems in manipulation is the development of immobilizing grasps. The same problem exists for flexible objects. I have shown that a simple polygonal piece of cloth can be fully immobilized by grasping all …


Quantification Of Artistic Style Through Sparse Coding Analysis In The Drawings Of Pieter Bruegel The Elder, James M. Hughes, Daniel J. Graham, Daniel N. Rockmore Jan 2010

Quantification Of Artistic Style Through Sparse Coding Analysis In The Drawings Of Pieter Bruegel The Elder, James M. Hughes, Daniel J. Graham, Daniel N. Rockmore

Dartmouth Scholarship

Recently, statistical techniques have been used to assist art historians in the analysis of works of art. We present a novel technique for the quantification of artistic style that utilizes a sparse coding model. Originally developed in vision research, sparse coding models can be trained to represent any image space by maximizing the kurtosis of a representation of an arbitrarily selected image from that space. We apply such an analysis to successfully distinguish a set of authentic drawings by Pieter Bruegel the Elder from another set of well-known Bruegel imitations. We show that our approach, which involves a direct comparison …


Anonytl Specification, Dan Peebles, Cory Cornelius, Apu Kapadia, David Kotz, Minho Shin, Nikos Triandopoulos Jan 2010

Anonytl Specification, Dan Peebles, Cory Cornelius, Apu Kapadia, David Kotz, Minho Shin, Nikos Triandopoulos

Computer Science Technical Reports

We provide a specification of AnonyTL, a domain-specific language that describes sensing tasks for mobile devices in a manner that facilitates automated reasoning about privacy.


On The Reliability Of Wireless Fingerprinting Using Clock Skews, Chrisil Arackaparambil, Sergey Bratus, Anna Shubina, David Kotz Jan 2010

On The Reliability Of Wireless Fingerprinting Using Clock Skews, Chrisil Arackaparambil, Sergey Bratus, Anna Shubina, David Kotz

Computer Science Technical Reports

Determining whether a client station should trust an access point is a known problem in wireless security. Traditional approaches to solving this problem resort to cryptography. But cryptographic exchange protocols are complex and therefore induce potential vulnerabilities in themselves. We show that measurement of clock skews of access points in an 802.11 network can be useful in this regard, since it provides fingerprints of the devices. Such fingerprints can be used to establish the first point of trust for client stations wishing to connect to an access point. Fingerprinting can also be used in the detection of fake access points. …


User Survey Regarding The Needs Of Network Researchers In Trace-Anonymization Tools, Jihwang Yeo, Keren Tan, David Kotz Nov 2009

User Survey Regarding The Needs Of Network Researchers In Trace-Anonymization Tools, Jihwang Yeo, Keren Tan, David Kotz

Computer Science Technical Reports

To understand the needs of network researchers in an anonymization tool, we conducted a survey on the network researchers. We invited network researchers world-wide to the survey by sending invitation emails to well-known mailing lists whose subscribers may be interested in network research with collecting, sharing and sanitizing network traces.


A Privacy Framework For Mobile Health And Home-Care Systems, David Kotz, Sasikanth Avancha, Amit Baxi Nov 2009

A Privacy Framework For Mobile Health And Home-Care Systems, David Kotz, Sasikanth Avancha, Amit Baxi

Dartmouth Scholarship

In this paper, we consider the challenge of preserving patient privacy in the context of mobile healthcare and home-care systems, that is, the use of mobile computing and communications technologies in the delivery of healthcare or the provision of at-home medical care and assisted living. This paper makes three primary contributions. First, we compare existing privacy frameworks, identifying key differences and shortcomings. Second, we identify a privacy framework for mobile healthcare and home-care systems. Third, we extract a set of privacy properties intended for use by those who design systems and applications for mobile healthcare and home-care systems, linking them …


Mpcs: Mobile-Based Patient Compliance System For Chronic Illness Care, Guanling Chen, Bo Yan, Minho Shin, David Kotz, Ethan Burke Nov 2009

Mpcs: Mobile-Based Patient Compliance System For Chronic Illness Care, Guanling Chen, Bo Yan, Minho Shin, David Kotz, Ethan Burke

Dartmouth Scholarship

More than 100 million Americans are currently living with at least one chronic health condition and expenditures on chronic diseases account for more than 75 percent of the $2.3 trillion cost of our healthcare system. To improve chronic illness care, patients must be empowered and engaged in health self-management. However, only half of all patients with chronic illness comply with treatment regimen. The self-regulation model, while seemingly valuable, needs practical tools to help patients adopt this self-centered approach for long-term care. \par In this position paper, we propose Mobile-phone based Patient Compliance System (MPCS) that can reduce the time-consuming and …


Katana: A Hot Patching Framework For Elf Executables, Ashwin Ramaswamy, Sergey Bratus, Michael E. Locasto, Sean W. Smith Nov 2009

Katana: A Hot Patching Framework For Elf Executables, Ashwin Ramaswamy, Sergey Bratus, Michael E. Locasto, Sean W. Smith

Computer Science Technical Reports

Despite advances in software modularity, security, and reliability, offline patching remains the predominant form of updating or protecting commodity software. Unfortunately, the mechanics of hot patching (the process of upgrading a program while it executes) remain understudied, even though such a capability offers practical benefits for both consumer and mission-critical systems. A reliable hot patching procedure would serve particularly well by reducing the downtime necessary for critical functionality or security upgrades. Yet, hot patching also carries the risk -- real or perceived -- of leaving the system in an inconsistent state, which leads many owners to forego its benefits as …


Activity-Aware Ecg-Based Patient Authentication For Remote Health Monitoring, Janani Sriram, Minho Shin, Tanzeem Choudhury, David Kotz Nov 2009

Activity-Aware Ecg-Based Patient Authentication For Remote Health Monitoring, Janani Sriram, Minho Shin, Tanzeem Choudhury, David Kotz

Dartmouth Scholarship

Mobile medical sensors promise to provide an efficient, accurate, and economic way to monitor patients' health outside the hospital. Patient authentication is a necessary security requirement in remote health monitoring scenarios. The monitoring system needs to make sure that the data is coming from the right person before any medical or financial decisions are made based on the data. Credential-based authentication methods (e.g., passwords, certificates) are not well-suited for remote healthcare as patients could hand over credentials to someone else. Furthermore, one-time authentication using credentials or trait-based biometrics (e.g., face, fingerprints, iris) do not cover the entire monitoring period and …


Activity-Aware Ecg-Based Patient Authentication For Remote Health Monitoring, Janani Sriram, Minho Shin, Tanzeem Choudhury, David Kotz Nov 2009

Activity-Aware Ecg-Based Patient Authentication For Remote Health Monitoring, Janani Sriram, Minho Shin, Tanzeem Choudhury, David Kotz

Dartmouth Scholarship

Mobile medical sensors promise to provide an efficient, accurate, and economic way to monitor patients' health outside the hospital. Patient authentication is a necessary security requirement in remote health monitoring scenarios. The monitoring system needs to make sure that the data is coming from the right person before any medical or financial decisions are made based on the data. Credential-based authentication methods (e.g., passwords, certificates) are not well-suited for remote healthcare as patients could hand over credentials to someone else. Furthermore, one-time authentication using credentials or trait-based biometrics (e.g., face, fingerprints, iris) do not cover the entire monitoring period and …


Activity-Aware Electrocardiogram-Based Passive Ongoing Biometric Verification, Janani C. Sriram Sep 2009

Activity-Aware Electrocardiogram-Based Passive Ongoing Biometric Verification, Janani C. Sriram

Dartmouth College Master’s Theses

Identity fraud due to lost, stolen or shared information or tokens that represent an individual's identity is becoming a growing security concern. Biometric recognition - the identification or verification of claimed identity, shows great potential in bridging some of the existing security gaps. It has been shown that the human Electrocardiogram (ECG) exhibits sufficiently unique patterns for use in biometric recognition. But it also exhibits significant variability due to stress or activity, and signal artifacts due to movement. In this thesis, we develop a novel activity-aware ECG-based biometric recognition scheme that can verify/identify under different activity conditions. From a pattern …


Semantic And Visual Encoding Of Diagrams, Gabriel A. Weaver Aug 2009

Semantic And Visual Encoding Of Diagrams, Gabriel A. Weaver

Computer Science Technical Reports

Constructed geometric diagrams capture a dynamic relationship between text and image that played a central role in ancient science and mathematics. Euclid, Theodosius, Ptolemy, Archimedes and others constructed diagrams to geometrically model optics, astronomy, cartography, and hydrostatics. Each derived geometric properties from their models and interpreted their results with respect to the model's underlying semantics. Although diagram construction is a dynamic process, the media in which these works were published (manuscripts and books) forced scholars to either view a snapshot of that process (a static image) or manually perform the entire construction. Mainstream approaches to digitization represent constructed diagrams as …


Dartmouth Internet Security Testbed (Dist): Building A Campus-Wide Wireless Testbed, Sergey Bratus, David Kotz, Keren Tan, William Taylor, Anna Shubina, Bennet Vance, Michael E. Locasto Aug 2009

Dartmouth Internet Security Testbed (Dist): Building A Campus-Wide Wireless Testbed, Sergey Bratus, David Kotz, Keren Tan, William Taylor, Anna Shubina, Bennet Vance, Michael E. Locasto

Dartmouth Scholarship

We describe our experiences in deploying a campus-wide wireless security testbed. The testbed gives us the capability to monitor security-related aspects of the 802.11 MAC layer in over 200 diverse campus locations. We describe both the technical and the social challenges of designing, building, and deploying such a system, which, to the best of our knowledge, is the largest such testbed in academia (with the UCSD's Jigsaw infrastructure a close competitor). In this paper we focus on the \em testbed setup, rather than on the experimental data and results.