The Dark Web Phenomenon: A Review and Research Agenda

The internet can be broadly divided into three parts: surface, deep and dark. The dark web has become notorious in the media for being a hidden part of the web where all manner of illegal activities take place. This review investigates how the dark web is being utilised with an emphasis on cybercrime, and how law enforcement plays the role of its adversary. The review describes these hidden spaces, sheds light on their history, the activities that they harbour – including cybercrime, the nature of attention they receive, and methodologies employed by law enforcement in an attempt to defeat their purpose. More importantly, it is argued that these spaces should be considered a phenomenon and not an isolated occurrence to be taken as merely a natural consequence of technology. This paper contributes to the area of dark web research by serving as a reference document and by proposing a research agenda

A numerical tool for the study of the hydrodynamic recovery of the Lattice Boltzmann Method

We investigate the hydrodynamic recovery of Lattice Boltzmann Method (LBM) by analyzing exact balance relations for energy and enstrophy derived from averaging the equations of motion on sub-volumes of different sizes. In the context of 2D isotropic homogeneous turbulence, we first validate this approach on decaying turbulence by comparing the hydrodynamic recovery of an ensemble of LBM simulations against the one of an ensemble of Pseudo-Spectral (PS) simulations. We then conduct a benchmark of LBM simulations of forced turbulence with increasing Reynolds number by varying the input relaxation times of LBM. This approach can be extended to the study of implicit subgrid-scale (SGS) models, thus offering a promising route to quantify the implicit SGS models implied by existing stabilization techniques within the LBM framework

Flight Dynamics Model of A Small Flexible Aircraft

University of Minnesota Ph.D. dissertation. December 2019. Major: Aerospace Engineering and Mechanics. Advisors: Peter Seiler, Gary Balas. 1 computer file (PDF); xii, 139 pages.The presence of aeroservoelastic effects in the flight dynamics of flexible aircraft presents significant challenges in terms of performance degradation and instability. In order to develop control system for such aircraft, an accurate flight dynamics model is needed. Developing such a model is an multi-disciplinary effort and re- quires theoretical and experimental knowledge and research. This thesis describes the development of the flight dynamics model of a small, flexible aircraft. Each step of the multi-stage process of the development of the flight dynamics model is described. The steps include designing and conducting vibration experiments on the aircraft for system identification of the structural dynamics and the devel- opment of a finite element model based structural model based on the acquired data. Aerodynamic models are developed and implemented using modifications of standard vortex and doublet lattice methods. The purpose of the modifications is to capture the geometric nonlinearity. The effects of these complex phenomena on the flight dynamics and instability (flutter) are analyzed. Mean axes based flight dynamics equations are utilized. These subcomponents are implemented in the simulation software SIMULINK to obtain the flight dynamics model. Flight tests are conducted to obtain data which is used to update the flight dynamics model by updating the aerodynamics model of the aircraft. A correction matrices based approach is used for this purpose. The resulting model has low computational cost but is capable of capturing complex behavior like geometric nonlinearities and un- steady aerodynamics. The low computational cost and modularity of the flight dynamics model makes it ideal for analysis of the effect of various kinds of aero- dynamics and structural phenomena. For example, the significant effects of the capturing the geometrically nonlinear aerodynamics on flutter characteristics of the aircraft are easily evaluated by this model without long, tedious and resource intensive computations. The model is also suitable for Monte-Carlo analysis to estimate the effect of various kinds of open-loop and closed-loop uncertainties

The dark web as a phenomenon: a review and research agenda

© 2018 Abhineet GuptaThe internet can broadly be divided into three parts: surface, deep and dark among which the latter offers anonymity to its users and hosts. The dark web has become notorious in the media for being a hidden part of the web where all manner of illegal activities take place. The more restrictions placed upon the free exchange of information, goods and services between people the more likely there exist hidden spaces for it to take place. The ‘black market’ of the internet – the dark web - represents such a hidden space. This review looks at the purposes it is widely used for with an emphasis on cybercrime, and how the law enforcement plays the role of its adversary. The review describes these hidden spaces, sheds light on their history, the activities that they harbour – including cybercrime, the nature of attention they receive, and methodologies employed by law enforcement in an attempt to defeat their purpose. More importantly, it is argued that these spaces should be considered a phenomenon and not an isolated occurrence to be taken as merely a natural consequence of technology. The review is conducted by looking at existing literature in academic journal databases. It contributes to the area of the dark web by serving as a reference document and by proposing a research agenda

Ground Vibration Test Time Domain Data

Included is time domain data for GVT testing on the BFF vehicle using a shaker as an excitation input

Aeroacoustic Investigation of Beveled Trailing Edges by High-Speed Particle Image Velocimetry

The aerodynamic noise generated by trailing edge of aircraft wings at take-o_ and approach con_guration continues to be a critical factor in the future development of aviation. Trailing edge noise is also a serious concern for wind turbines, marine propellers, helicopter rotors, axial and centrifugal turbines and compressors. A fundamental understanding of how the energy contained in turbulent motions around trailing edges is converted to sound will be bene_cial for designing silent airfoils and control surfaces. Current research aims at applying new tools of ow _eld interrogation i.e. high-speed planar and tomographic PIV to the canonical problem of trailing edge noise. In analytical models, the far _eld noise can be described using turbulent quantities like the spanwise coherence. The use of high-speed tomographic PIV creates a link between the phenomenological description of the ow and acoustic _eld in terms of coherence of structures and noise. The geometric con_guration used involves an airfoil with an elliptic leading edge and an asymmetric beveled trailing edge with 25 deg tip angle (_) and three di_erent radii of curvature (R). The measurements are taken at four di_erent Reynolds numbers.Aerospace Engineering | Aerodynamics and Wind Energ

A Bayesian change point model to detect changes in event occurrence rates, with application to induced seismicity

A significant increase in earthquake occurrence rates has been observed in recent years in parts of Central and Eastern US. There is a possibility that this increased seismicity is anthropogenic and is referred to as induced seismicity. In this paper, a Bayesian change point model is implemented to evaluate whether temporal features of observed earthquakes support the hypothesis that a change in seismicity rates has occurred. This model is then used to estimate when the change is likely to have occurred. The magnitude of change is also quantified by estimating the distributions of seismicity rates before and after the change. These calculations are validated using a simulated data set with a known change point and event occurrence rates; and then applied to earthquake occurrence data for a site in Oklahoma.Non UBCUnreviewedThis collection contains the proceedings of ICASP12, the 12th International Conference on Applications of Statistics and Probability in Civil Engineering held in Vancouver, Canada on July 12-15, 2015. Abstracts were peer-reviewed and authors of accepted abstracts were invited to submit full papers. Also full papers were peer reviewed. The editor for this collection is Professor Terje Haukaas, Department of Civil Engineering, UBC Vancouver.Facult

Low lying fistula-in-ano - fistulotomy or fistulectomy

Background: Fistula-in-ano is very common benign anal condition in day to day surgical practice which is treatable. The treatment is challenging even for an experienced surgeons due to its chronic and recurring nature. There are various treatment modalities available for management of anal fistula. Our aim is to study the outcome of fistulotomy and fistulectomy in patients with simple low-lying fistula. Methods: A prospective Randomised clinical study was done on 55 patients, they were randomized into two groups of fistulotomy (n=25) and fistulectomy (n=30) in GSVM medical college over a period of two years. Aim of the study was to compare the operative time, healing time, treatment outcome, complications and recurrence rate. The results were analyzed using SPSS version 22 using tests like student’s t test and chi square test. Results: The mean operative time of fistulotomy was 18.3 minutes and that of fistulectomy was 34.2 minutes, which is statistically significant ( p-value =0.008).Duration of healing in fistulotomy group (11 days) compared to fistulectomy group (22 days), which is statistically significant (p<0.001).Incidence of incontinence in fistulotomy group observed in 2 cases and in fistulectomy group was observed in 3 cases , which is insignificant (p-value=.797)There was recurrence in one case in both the groups in six months of follow-up period. Conclusion: Fistulotomy is better for treating low fistula-in-ano in terms of high healing rate, shorter operating time, shorter healing time which ultimately reduces the hospital stay and incidence of complications is comparable in both the groups