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Full-Text Articles in Physical Sciences and Mathematics
The Good, The Bad, And The Actively Verified, John Williamson
The Good, The Bad, And The Actively Verified, John Williamson
Dartmouth College Master’s Theses
We believe that we can use active probing for compromise recovery. Our intent is to exploit the differences in behavior between compromised and uncompromised systems and use that information to identify those which are not behaving as expected. Those differences may indicate a deviation in either con figuration or implementation from what we expect on the network, either of which suggests that the misbehaving entity might not be trustworthy. In this work, we propose and build a case for a method for using altered behavior directly resulting from or introduced as a side-effect of the compromise of a network service …
Tackling Latency Using Fg, Priya Natarajan
Tackling Latency Using Fg, Priya Natarajan
Dartmouth College Ph.D Dissertations
Applications that operate on datasets which are too big to fit in main memory, known in the literature as external-memory or out-of-core applications, store their data on one or more disks. Several of these applications make multiple passes over the data, where each pass reads data from disk, operates on it, and writes data back to disk. Compared with an in-memory operation, a disk-I/O operation takes orders of magnitude (approx. 100,000 times) longer; that is, disk-I/O is a high-latency operation. Out-of-core algorithms often run on a distributed-memory cluster to take advantage of a cluster's computing power, memory, disk space, and …
Anomaly Detection In Network Streams Through A Distributional Lens, Chrisil Arackaparambil
Anomaly Detection In Network Streams Through A Distributional Lens, Chrisil Arackaparambil
Dartmouth College Ph.D Dissertations
Anomaly detection in computer networks yields valuable information on events relating to the components of a network, their states, the users in a network and their activities. This thesis provides a unified distribution-based methodology for online detection of anomalies in network traffic streams. The methodology is distribution-based in that it regards the traffic stream as a time series of distributions (histograms), and monitors metrics of distributions in the time series. The effectiveness of the methodology is demonstrated in three application scenarios. First, in 802.11 wireless traffic, we show the ability to detect certain classes of attacks using the methodology. Second, …
Autoscopy Jr.: Intrusion Detection For Embedded Control Systems, Jason O. Reeves
Autoscopy Jr.: Intrusion Detection For Embedded Control Systems, Jason O. Reeves
Dartmouth College Master’s Theses
Securing embedded control systems within the power grid presents a unique challenge: on top of the resource restrictions inherent to these devices, SCADA systems must also accommodate strict timing requirements that are non-negotiable, and their massive scale greatly amplifies costs such as power consumption. These constraints make the conventional approach to host intrusion detection--namely, employing virtualization in some manner--too costly or impractical for embedded control systems within critical infrastructure. Instead, we take an in-kernel approach to system protection, building upon the Autoscopy system developed by Ashwin Ramaswamy that places probes on indirectly-called functions and uses them to monitor its host …
Large-Scale Wireless Local-Area Network Measurement And Privacy Analysis, Keren Tan
Large-Scale Wireless Local-Area Network Measurement And Privacy Analysis, Keren Tan
Dartmouth College Ph.D Dissertations
The edge of the Internet is increasingly becoming wireless. Understanding the wireless edge is therefore important for understanding the performance and security aspects of the Internet experience. This need is especially necessary for enterprise-wide wireless local-area networks (WLANs) as organizations increasingly depend on WLANs for mission- critical tasks. To study a live production WLAN, especially a large-scale network, is a difficult undertaking. Two fundamental difficulties involved are (1) building a scalable network measurement infrastructure to collect traces from a large-scale production WLAN, and (2) preserving user privacy while sharing these collected traces to the network research community. In this dissertation, …
Obstruction-Free Snapshot, Obstruction-Free Consensus, And Fetch-And-Add Modulo K, Jack R. Bowman
Obstruction-Free Snapshot, Obstruction-Free Consensus, And Fetch-And-Add Modulo K, Jack R. Bowman
Dartmouth College Undergraduate Theses
In this thesis we design algorithms for three problems: snapshot, consensus, and fetch-and-add modulo k. Our solutions for snapshot and consensus are non-anonymous and obstruction-free, and our solution for Fetch-and-add Modulo k is wait-free. We also conjecture an anonymous, obstruction-free solution to consensus.
A Solution To K-Exclusion With O(Logk) Rmr Complexity, Jonathan H. Choi
A Solution To K-Exclusion With O(Logk) Rmr Complexity, Jonathan H. Choi
Dartmouth College Undergraduate Theses
We specify and prove an algorithm solving k-Exclusion, a generalization of the Mutual Exclusion problem. k-Exclusion requires that at most k processes be in the Critical Section (CS) at once; in addition, we require bounded exit, starvation freedom and fairness properties. The goal within this framework is to minimize the number of Remote Memory References (RMRs) made. Previous algorithms have required Omega(k) RMRs in the worst case. Our algorithm requires O(log k) RMRs in the worst case under the Cache-Coherent (CC) model, a considerable improvement in time complexity.
A Multilevel, Posture-Based Model For Motor Control In Simulation And Robotic Applications, Divya A. Gunasekaran
A Multilevel, Posture-Based Model For Motor Control In Simulation And Robotic Applications, Divya A. Gunasekaran
Dartmouth College Undergraduate Theses
This paper presents a multilevel, posture-based motor control model intended to plan collision-free movements in a 3D environment while maintaining computationally efficiency and accurately imitating human and primate motor function. Our model is a comprehensive approach that addresses the storage and lookup of postures and movements, path planning and the generation of new movements, and learning with experience. We demonstrate the functionality and computational advantages of the model through preliminary testing on a humanoid robot.
Reader-Writer Exclusion Supporting Upgrade And Downgrade With Reader-Priority, Michael I. Diamond
Reader-Writer Exclusion Supporting Upgrade And Downgrade With Reader-Priority, Michael I. Diamond
Dartmouth College Undergraduate Theses
The Reader-Writer Exclusion problem seeks to provide a lock that protects some critical section of code for two classes of processes, readers and writers, where multiple readers are permitted to hold the lock at a time, but only one writer can hold the lock to the exclusion of all other processes. The difficulties in solving this problem lie not only in developing a good algorithm, but in rigorously formulating desirable properties for such an algorithm to have. Recently, Bhatt and Jayanti accomplished both of these tasks for several variants of the Reader-Writer Exclusion problem. We seek to extend their work …
Constant-Rmr Abortable Reader-Priority Reader-Writer Algorithm, Nan Zheng
Constant-Rmr Abortable Reader-Priority Reader-Writer Algorithm, Nan Zheng
Dartmouth College Undergraduate Theses
The concurrent reader-writer problem (Courtois, 1971) involves two classes of processes: readers and writers, both of which wish to access a shared resource. Many readers can access the shared resource at the same time. However, if a writer is accessing the resource, no readers or other writers can access the resource at the same time. In the reader-priority version of the problem, readers are prioritized over writers when processes from both classes are trying to access the shared resource. Previous research (Bhatt, 2010) showed a reader-priority constant-RMR multi-reader, multi-writer algorithm for Cache-Coherent (CC) systems. However, this algorithm does not allow …
Exploiting The Hard-Working Dwarf: Trojan And Exploit Techniques Without Native Executable Code, James M.H. Oakley
Exploiting The Hard-Working Dwarf: Trojan And Exploit Techniques Without Native Executable Code, James M.H. Oakley
Dartmouth College Undergraduate Theses
The study of vulnerabilities and exploitation is one of finding mechanisms affecting the flow of computation and of finding new means to perform unexpected computation. In this paper we show the extent to which exception handling mechanisms as implemented and used by \gcc can be used to control program execution. We show that the data structures used to store exception handling information on UNIX-like systems actually contain Turing-complete bytecode, which is executed by a virtual machine during the course of exception unwinding and handling. We discuss how a malicious attacker could gain control over these structures and how such an …
Ieee 802.15.4 Wireless Security: Self-Assessment Frameworks, Ryan Speers
Ieee 802.15.4 Wireless Security: Self-Assessment Frameworks, Ryan Speers
Dartmouth College Undergraduate Theses
This thesis analyzes the security of networks built upon the IEEE 802.15.4 standard, specifically in regard to the ability of an attacker to manipulate such networks under real-world conditions. The author presents a set of tools, both hardware and software, that advance the state-of-the-art in reconnaissance and site surveying, intelligent packet generation, and launching of attacks. Specifically, tools provide increased hardware support for the KillerBee toolkit, a Scapy layer for forming 802.15.4 packets, reflexive jamming of packets, and other research enablers. This work aims to advance the ability of security auditors to understand the threats to IEEE 802.15.4 networks by …
Reader-Writer Exclusion Supporting Upgrade And Downgrade With Starvation Freedom, Matthew Elkherj
Reader-Writer Exclusion Supporting Upgrade And Downgrade With Starvation Freedom, Matthew Elkherj
Dartmouth College Undergraduate Theses
In this thesis we give a constant Remote-Memory-Reference (on CC systems) reader-writer exclusion algorithm supporting upgrade and downgrade, built from a reader-writer exclusion algorithm by Jayanti and Liu. The algorithm is starvation-free, and allows for repeated upgrades and downgrades.
Assisting Human Motion-Tasks With Minimal, Real-Time Feedback, Paritosh A. Kavathekar
Assisting Human Motion-Tasks With Minimal, Real-Time Feedback, Paritosh A. Kavathekar
Dartmouth College Ph.D Dissertations
Teaching physical motions such as riding, exercising, swimming, etc. to human beings is hard. Coaches face difficulties in communicating their feedback verbally and cannot correct the student mid-action; teaching videos are two dimensional and suffer from perspective distortion. Systems that track a user and provide him real-time feedback have many potential applications: as an aid to the visually challenged, improving rehabilitation, improving exercise routines such as weight training or yoga, teaching new motion tasks, synchronizing motions of multiple actors, etc. It is not easy to deliver real-time feedback in a way that is easy to interpret, yet unobtrusive enough to …
Effects Of Network Trace Sampling Methods On Privacy And Utility Metrics, Phillip A. Fazio
Effects Of Network Trace Sampling Methods On Privacy And Utility Metrics, Phillip A. Fazio
Dartmouth College Undergraduate Theses
Researchers studying computer networks rely on the availability of traffic trace data collected from live production networks. Those choosing to share trace data with colleagues must first remove or otherwise anonymize sensitive information. This process, called sanitization, represents a tradeoff between the removal of information in the interest of identity protection and the preservation of data within the trace that is most relevant to researchers. While several metrics exist to quantify this privacy-utility tradeoff, they are often computationally expensive. Computing these metrics using a sample of the trace, rather than the entire input trace, could potentially save precious time and …
Minimum Time Kinematic Trajectories For Self-Propelled Rigid Bodies In The Unobstructed Plane, Andrei A. Furtuna
Minimum Time Kinematic Trajectories For Self-Propelled Rigid Bodies In The Unobstructed Plane, Andrei A. Furtuna
Dartmouth College Ph.D Dissertations
The problem of moving rigid bodies efficiently is of particular interest in robotics because the simplest model of a mobile robot or of a manipulated object is often a rigid body. Path planning, controller design and robot design may all benefit from precise knowledge of optimal trajectories for a set of permitted controls. In this work, we present a general solution to the problem of finding minimum time trajectories for an arbitrary self-propelled, velocity-bounded rigid body in the obstacle-free plane. Such minimum-time trajectories depend on the vehicle’s capabilities and on and the start and goal configurations. For example, the fastest …
802.15.4/Zigbee Analysis And Security: Tools For Practical Exploration Of The Attack Surface, Ricky A. Melgares
802.15.4/Zigbee Analysis And Security: Tools For Practical Exploration Of The Attack Surface, Ricky A. Melgares
Dartmouth College Undergraduate Theses
This thesis explores methods and techniques for surveying 802.15.4 and ZigBee wireless networks. The tools developed will aid in reconnaissance attacks against target networks; information gathered during this process will be used to profile a target network and its devices, as well as to pinpoint the geolocation of devices for executing physical attacks against the onboard hardware. Attacks against the PHY and MAC layers of the 802.15.4 standard will be explored as well.
Static Analysis For Ruby In The Presence Of Gradual Typing, Michael Edgar
Static Analysis For Ruby In The Presence Of Gradual Typing, Michael Edgar
Dartmouth College Undergraduate Theses
Dynamic languages provide new challenges to traditional static analysis techniques, leaving most errors to be detected at runtime and making many properties of code difficult to infer. Ruby code usually takes advantage of both dynamic typing and metaprogramming to produce elegant yet difficult-to-analyze programs. Function evalpq and its variants, which usually foil static analysis, are used frequently as a primitive runtime macro system. The goal of this thesis is to answer the question: What useful information about real-world Ruby programs can be determined statically with a high degree of accuracy? Two observations lead to a number of statically-discoverable errors and …
Screen Capture For Sensitive Systems, Joseph A. Cooley
Screen Capture For Sensitive Systems, Joseph A. Cooley
Dartmouth College Master’s Theses
Maintaining usable security in application domains such as healthcare or power systems requires an ongoing conversation among stakeholders such as end-users, administrators, developers, and policy makers. Each party has power to influence the design and implementation of the application and its security posture, and effective communication among stakeholders is one key to achieving influence and adapting an application to meet evolving needs. In this thesis, we develop a system that combines keyboard/video/mouse (KVM) capture with automatic text redaction to produce precise technical content that can enrich stakeholder communications, improve end-user influence on system evolution, and help reveal the definition of …
Appearance-Design Interfaces And Tools For Computer Cinematography: Evaluation And Application, William B. Kerr
Appearance-Design Interfaces And Tools For Computer Cinematography: Evaluation And Application, William B. Kerr
Dartmouth College Ph.D Dissertations
We define appearance design as the creation and editing of scene content such as lighting and surface materials in computer graphics. The appearance design process takes a significant amount of time relative to other production tasks and poses difficult artistic challenges. Many user interfaces have been proposed to make appearance design faster, easier, and more expressive, but no formal validation of these interfaces had been published prior to our body of work. With a focus on novice users, we present a series of investigations into the strengths and weaknesses of various appearance design user interfaces. In particular, we develop an …