Thesis (M.S.)--Oregon State University, 1987. / Typescript (photocopy). Includes bibliographical references (leaves 131-140). Also available on the World Wide Web.

This thesis investigates the effect of viscous damping on rogue wave formation and permanent downshift using the higher-order nonlinear Schrödinger equation (HONLS). The strength of viscous damping is varied and compared to experiments with only linear damped HONLS. Stability analysis of the linear damped HONLS equation shows that instability stabilizes over time. This analysis also provides an instability criterion in the case of HONLS with viscous damping. Numerical experiments are conducted in the two unstable mode regime using perturbations of the Stokes wave as initial data. With only linear damping permanent downshift is not observed and rogue wave formation is decreased. The addition of viscous damping leads to permanent downshift and a slight increase in rogue wave activity. Analysis of the energy and momentum gives a possible explanation for this behavior.

In this thesis we construct rogue waves occurring in the sine-Gordon equation. An algebraic method is used to find explicit solutions to a Lax pair of equations. The Lax pair being studied is compatible with solutions to the sine-Gordon equation. Rotational and librational traveling wave solutions to the sine-Gordon equation are considered in the Lax pair. The Darboux transformation is applied with the Lax pair solutions computed at the rotational and librational waves to generate algebraic solitons and rogue waves, respectively. The rogue waves occur on the end points of the Floquet-Lax spectrum bands and can achieve a magnification factor of at most 3. / Thesis / Master of Science (MSc)

The study of large nonlinear waves that seem to “appear out of nowhere and disappear without a trace”, known as rogue or freak waves, began largely in response to observations of catastrophic ocean waves. However, the study of rogue waves has since been expanded to a wider collection of physical scenarios, including discrete systems, such as those that appear in optics, as opposed to the continuous system of water waves. Waves in these discrete settings can be modeled as solutions to lattice wave equations. The nonlinear Schrodinger equation (NLSE) is one of the most ubiquitous continuous wave models for physical systems where rogue waves emerge. This thesis focuses on the two discrete analogs of the NLSE: a non-integrable model called the discrete nonlinear Schrodinger equation (DNLS) and its integrable sibling called the Ablowitz-Ladik (AL) equation. The physical relevance of DNLS model motivates the search for its rogue wave solutions; a search that is impeded by its lack of integrability. However, it is homotopically paired with the integrable AL equation through the Salerno model, providing a potential outlet to find numerically exact solutions. This threefold investigation will look at: (i) finding time-periodic solutions to the DNLS atop a constant non-zero background, (ii) proximity of solutions to the AL and DNLS equations over time, and (iii) time-periodic solutions to the defocusing AL model.

A comprehensive experimental study was conducted to produce benchmark wave kinematics data for five different regular waves and the maxima of four different irregular wave trains. Two of the irregular waves generated are in the category of rogue waves. A series of experiments were conducted in a 2-D wave tank at Texas A&M University to measure wave velocities and accelerations using LDV and PIV systems. The wave crests of regular and rogue waves are the focus of this study. With the measured wave velocity field, the wave accelerations were computed using a centered finite difference scheme. Both local and convective components of the total accelerations are obtained from experimental data. Also, the nonlinear wave forces on a truncated slender cylinder are computed by applying the obtained wave kinematics to the Morison equation. The force results based on measured wave kinematics are compared with those based on the kinematics of linear extrapolation, Wheeler stretching, and modified stretching. The Wheeler stretching method generally underestimates the actual wave kinematics. The linear extrapolation method is very sensitive to the cutoff frequency of the wave spectrum. The modified stretching method tends to predict the maximum value of wave kinematics above the still water level (SWL) well except for the convective acceleration. The magnitude of convective acceleration in the regular waves was negligibly small, whereas the magnitudes of horizontal and vertical convective accelerations in the rogue wave were increased rapidly above the SWL.

Phishing is an internet security issue whose shape is still changing and size is still increasing. This thesis shows the possibility of a phishing attack on open, private Wireless LANs. Private WLANs which use a login page to authenticate users in hotels, airports and academic campuses are all vulnerable to this attack. Virginia Tech's WLAN is used as an example to show that the attack is possible. The attack combines two very well known attacks: one is to deceptively guide a user into logging into a fake website, which shows similar log-in page to the page of the website the user intends to go to, and the second attack is to show users a valid certificate, which does not show a warning. The rogue server takes the user to a log-in page which is similar to Virginia Tech's log-in page and shows him a valid security certificate. We present a solution to the proposed problem. Software is implemented that runs on Windows Vista. The software warns the user if there are servers with more than one type of security certificates, claiming to be from the same network. We contrast our method to already existing methods, and show in what respects our solution is better. The biggest advantage of this method is that it involves no change on the server side. It is not necessary for the users to have any prior knowledge of the network, which is very helpful when the users access WLAN at airports and hotels. Also, when using this method, the user does not need to connect to any network, and is still able to get a warning. It however, requires the user to be able to differentiate between the real and fake networks after the user has been warned. / Master of Science

abstract: This project includes a recording, composer biographies, performance guides, and composer questionnaires for seven original works commissioned for either the Rogue Trio or Lotus. The members of the Rogue Trio are violinist Kathleen Strahm, saxophonist Justin Rollefson, and pianist Mary Cota. Lotus’s members include Samuel Detweiler, Justin Rollefson, and Kristen Zelenak on saxophone. Both ensembles are based in Tempe, Arizona. All seven original compositions were recorded at Tempest Recording in February of 2018. The first piece, Four Impersonations (2016), was commissioned by the Rogue Trio and written by Theo Chandler (b.1992) for violin, soprano saxophone and piano. The second piece was written by Spencer Arias (b. 1990) titled He Said There Was No Sound (2015) for violin, alto saxophone, and piano. The final work is titled Cabinet Meeting (2017), composed by Zachary Green (b. 1993) for violin, alto and tenor saxophone, and piano. The first piece commissioned by Lotus and composed by Spencer Arias is titled As I escape, the water calms (2017) for soprano saxophone, alto saxophone, and tenor saxophone. The second piece was composed by Graham Cohen (b. 1999), titled Introduction and Toccata (2017), written for soprano, alto, and baritone saxophones. The third piece, titled Everything that rises, was written by David “Clay” Mettens (b. 1990) in 2014 for three soprano saxophones. Samuel Detweiler, Justin Rollefson and Tyler Flowers originally commissioned this piece. The final piece commissioned by Lotus was written by Matthew Kennedy (b. 1987) titled Triceratops: tasty grooves for saxophone trio (2017) for alto, tenor, and baritone saxophones. / Dissertation/Thesis / Four Impersonations, Movement I: An outwardly-confident adolescent demanding recognition - Theo Chandler / Four Impersonations, Movement II: A grumpy hermit ignoring the attention of a suitor - Theo Chandler / Four Impersonations, Movement III: A skinny, shy boy standing in the rain - Theo Chandler / Four Impersonations, Movement IV: Subordinates mocking an authority figure - Theo Chandler / He Said There Was No Sound - Spencer Arias / Cabinet Meeting, Movement I: Introduction - Zachary Green / Cabinet Meeting, Movement II: Jared Kushner, mysterious robot - Zachary Green / Cabinet Meeting, Movement III: Secretary of State Rex Tillerson, lonesome cowboy - Zachary Green / Cabinet Meeting, Movement IV: Anthony "The Mooch" Scaramucci, in candid conversation with the New Yorker - Zachary Green / Cabinet Meeting, Movement V: Betsy DeVos Secretary of Education - Zachary Green / Cabinet Meeting, Movement VI: Ben Carson Secretary of Housing and Urban Development - Zachary Green / Cabinet Meeting, Movement VII: Attorney General Jeff Sessions, responding to questions from the Senate Intelligence Committee - Zachary Green / As I escape, the water calms - Spencer Arias / Introduction and Toccata - Graham Cohen / Everything that rises - David “Clay” Mettens / Triceratops - Matthew Kennedy / Doctoral Dissertation Music 2018

Vehicular ad hoc networks (VANETs) facilitate vehicles to broadcast beacon messages to ensure road safety. The rogue nodes in VANETs broadcast malicious information leading to potential hazards, including the collision of vehicles. Previous researchers used either cryptography, trust values, or past vehicle data to detect rogue nodes, but they suffer from high processing delay, overhead, and false-positive rate (FPR). We propose fog-based rogue nodes detection (F-RouND), a fog computing scheme, which dynamically creates a fog utilizing the on-board units (OBUs) of all vehicles in the region for rogue nodes detection. The novelty of F-RouND lies in providing low processing delays and FPR at high vehicle densities. The performance of our F-RouND framework was carried out with simulations using OMNET ++ and SUMO simulators. Results show that F-RouND ensures 45% lower processing delays, 12% lower overhead, and 36% lower FPR at high vehicle densities compared to existing rogue nodes detection schemes.

Made available in DSpace on 2015-09-25T12:22:22Z (GMT). No. of bitstreams: 1 PDF - Murilo Mesquita Melo e Silva.pdf: 1437705 bytes, checksum: 8630b67ecc67f546ecd416e32a7434d7 (MD5) Previous issue date: 2013-04-01 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This Dissertation aims to analysis the formation and utilization of state taxonomies weak states and rogue states, according to their political instrumentalization. The hypothesis is that happened a conceptual and taxonomic restructuring from weak to rogue states since the securitization of underdevelopment of the weak states and of political instrumentalization of rogue states taxonomy. The analysis of hypothesis is based on postcolonial approaches as theoric-methodologic substratum. In analysis of weak states the aim is to contextualize the beginning of construction of this taxonomy, since of underdevelopment securitization process. In analysis of rogue states the aim is verified the process of construction of rogue taxonomy and how maintains this process itself. As final considerations, there is not a conceptual and taxonomic restructuring so unanimous. If the assumptions of Rational Modern State were accepted, some States may be considered weak, but not rogue, while another may be called rogue, but not weak. It was found, however, the political exploitation of state's taxonomies, according to the diagnoses made by outside actors of state to be cataloged, especially by the United States. / Essa dissertação tem por objetivo analisar a formação e utilização das taxonomias estatais weak states e rogue states à luz da instrumentalização política das mesmas. A hipótese é que houve uma reestruturação conceitual e taxonômica dos weak para rogue states a partir da securitização do subdesenvolvimento dos weak states e da instrumentalização política da taxonomia rogue states. Na análise da hipótese foram utilizadas as abordagens pós-coloniais como substrato teórico-metodológico. Na análise dos weak states o objetivo é contextualizar o início do processo de construção da taxonomia weak, desde o processo de securitização do subdesenvolvimento. Na análise dos rogue states o objetivo é verificar o processo de construção dessa taxonomia e como ela se sustenta. Por fim, considera-se que não há uma reestruturação conceitual e taxonômica de forma unânime. Se, se aceitar as premissas do Estado Racional Moderno, alguns Estados podem ser considerados weak, mas não rogue, enquanto outros podem ser rogue, mas não weak. O que se verifica, no entanto, é a instrumentalização política das taxonomias, segundo os diagnósticos elaborados por atores externos ao Estado a ser catalogado, principalmente pelos Estados Unidos.

Rogue waves are unexpected, individual ocean surface waves that are disproportionately large compared to the background sea state. They present considerable risk to mariners and offshore structures when encountered in large seas. Rogue waves have gone from seafarer’s folktales to an actively researched and debated phenomenon. In this work an easily derived spectral parameter, as an indicator of rogue wave risk, is presented, and further evidence for the generation mechanism responsible for these abnormal waves is provided. With the additional goal of providing a practical rogue wave forecast, the ability of a standard wave model to predict the rogue wave probability is assessed. Current forecasts, like those at the European Centre for Medium-Range Weather Forecasts (ECMWF), rely on the Benjamin Feir Index (BFI) as a rogue wave predictor, which reflects the nonlinear process of modulation instability as the generation mechanism for rogue waves. However, this analysis finds BFI has little predictive power in the real ocean. From the analysis of long term sea surface elevation records in nearshore areas and hourly bulk statistics from open ocean and coastal buoys in the Northeast Pacific, crest-trough correlation shows the highest correlation with rogue wave probability. These results provide evidence in support of a probabilistic prediction of rogue waves based on random linear superposition and should replace forecasts based on modulation instability. Crest-trough correlation was then forecast by a regional WAVEWATCH III ® wave model with moderate accuracy compared with the high performance of forecasting significant wave height. Results from a case study of a large fall storm October 21-22, 2021, are presented to show that the regional wave model produces accurate forecasts of significant wave height at high seas and presents a potential rogue wave probability forecast. / Graduate