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Articles 1 - 9 of 9
Full-Text Articles in Physical Sciences and Mathematics
Settling For Limited Privacy: How Much Does It Help?, Anna M. Shubina
Settling For Limited Privacy: How Much Does It Help?, Anna M. Shubina
Dartmouth College Ph.D Dissertations
This thesis explores practical and theoretical aspects of several privacy-providing technologies, including tools for anonymous web-browsing, verifiable electronic voting schemes, and private information retrieval from databases. State-of-art privacy-providing schemes are frequently impractical for implementational reasons or for sheer information-theoretical reasons due to the amount of information that needs to be transmitted. We have been researching the question of whether relaxing the requirements on such schemes, in particular settling for imperfect but sufficient in real-world situations privacy, as opposed to perfect privacy, may be helpful in producing more practical or more efficient schemes. This thesis presents three results. The first result …
Lighting And Optical Tools For Image Forensics, Micah Kimo Johnson
Lighting And Optical Tools For Image Forensics, Micah Kimo Johnson
Dartmouth College Ph.D Dissertations
We present new forensic tools that are capable of detecting traces of tampering in digital images without the use of watermarks or specialized hardware. These tools operate under the assumption that images contain natural properties from a variety of sources, including the world, the lens, and the sensor. These properties may be disturbed by digital tampering and by measuring them we can expose the forgery. In this context, we present the following forensic tools: (1) illuminant direction, (2) specularity, (3) lighting environment, and (4) chromatic aberration. The common theme of these tools is that they exploit lighting or optical properties …
A Security Assessment Of Trusted Platform Modules, Evan R. Sparks
A Security Assessment Of Trusted Platform Modules, Evan R. Sparks
Dartmouth College Undergraduate Theses
Trusted Platform Modules (TPMs) are becoming ubiquitous devices included in newly released personal computers. Broadly speaking, the aim of this technology is to provide a facility for authenticating the platform on which they are running: they are able to measure attest to the authenticity of a hardware and software configuration. Designed to be cheap, commodity devices which motherboard and processor vendors can include in their products with minimal marginal cost, these devices have a good theoretical design. Unfortunately, there exist several practical constraints on the effectiveness of TPMs and the architectures which employ them which leave them open to attack. …
Closest And Farthest-Line Voronoi Diagrams In The Plane, Mark C. Henle
Closest And Farthest-Line Voronoi Diagrams In The Plane, Mark C. Henle
Dartmouth College Undergraduate Theses
Voronoi diagrams are a geometric structure containing proximity information useful in efficiently answering a number of common geometric problems associated with a set of points in the plane.. They have applications in fields ranging from crystallography to biology. Diagrams of sites other than points and with different distance metrics have been studied. This paper examines the Voronoi diagram of a set of lines, which has escaped study in the computational geometry literature. The combinatorial and topological properties of the closest and farthest Voronoi diagrams are analyzed and O(n^2) and O(n log n) algorithms are presented for their computation respectively.
Exploring The Integration Of Memory Management And Trusted Computing, Nihal A. D'Cunha
Exploring The Integration Of Memory Management And Trusted Computing, Nihal A. D'Cunha
Dartmouth College Master’s Theses
This thesis addresses vulnerabilities in current Trusted Computing architecture by exploring a design for a better Trusted Platform Module (TPM); one that integrates more closely with the CPU's Memory Management Unit (MMU). We establish that software-based attacks on trusted memory can be carried out undetectably by an adversary on current TCG/TPM implementations. We demonstrate that an attacker with sufficient privileges can compromise the integrity of a TPM-protected system by modifying critical loaded code and static data after measurement has taken place. More specifically, these attacks illustrate the Time Of Check vs. Time of Use (TOCTOU) class of attacks. We propose …
Scml: A Structural Representation For Chinese Characters, Daniel G. Peebles
Scml: A Structural Representation For Chinese Characters, Daniel G. Peebles
Dartmouth College Undergraduate Theses
Chinese characters are used daily by well over a billion people. They constitute the main writing system of China and Taiwan, form a major part of written Japanese, and are also used in South Korea. Anything more than a cursory glance at these characters will reveal a high degree of structure to them, but computing systems do not currently have a means to operate on this structure. Existing character databases and dictionaries treat them as numerical code points, and associate with them additional `hand-computed' data, such as stroke count, stroke order, and other information to aid in specific searches. Searching …
Lighting With Sketches, Alexander Wakefield Steinberg
Lighting With Sketches, Alexander Wakefield Steinberg
Dartmouth College Undergraduate Theses
Lighting design is a fundamental aspect of computer cinematography, where it is used to support storytelling by affecting the mood, style, and believability of a scene. Traditionally, lighting has requred the tedious adjustment of large set parameters that describe complex lighting setups, including lights positions, colors, shapes, etc. This work presents an interactive user interface that facilitates lighting workflow by using a sketching paradigm for light creation. Lights are specified by a series of strokes that define various properties of illumination such as shape of the light and position of illuminated and shadowed areass. The system will them perform a …
Experiment Planning For Protein Structure Elucidation And Site-Directed Protein Recombination, Xiaoduan Ye
Experiment Planning For Protein Structure Elucidation And Site-Directed Protein Recombination, Xiaoduan Ye
Dartmouth College Ph.D Dissertations
In order to most effectively investigate protein structure and improve protein function, it is necessary to carefully plan appropriate experiments. The combinatorial number of possible experiment plans demands effective criteria and efficient algorithms to choose the one that is in some sense optimal. This thesis addresses experiment planning challenges in two significant applications. The first part of this thesis develops an integrated computational-experimental approach for rapid discrimination of predicted protein structure models by quantifying their consistency with relatively cheap and easy experiments (cross-linking and site-directed mutagenesis followed by stability measurement). In order to obtain the most information from noisy and …
Complete Configuration Space Analysis For Structure Determination Of Symmetric Homo-Oligomers By Nmr, Shobha Potluri
Complete Configuration Space Analysis For Structure Determination Of Symmetric Homo-Oligomers By Nmr, Shobha Potluri
Dartmouth College Ph.D Dissertations
Symmetric homo-oligomers (protein complexes with similar subunits arranged symmetrically) play pivotal roles in complex biological processes such as ion transport and cellular regulation. Structure determination of these complexes is necessary in order to gain valuable insights into their mechanisms. Nuclear Magnetic Resonance (NMR) spectroscopy is an experimental technique used for structural studies of such complexes. The data available for structure determination of symmetric homo-oligomers by NMR is often sparse and ambiguous in nature, raising concerns about existing heuristic approaches for structure determination. We have developed an approach that is complete in that it identifies all consistent conformations, data-driven in that …