The COST IRACON Geometry-based Stochastic Channel Model for Vehicle-to-Vehicle Communication in Intersections

Vehicle-to-vehicle (V2V) wireless communications can improve traffic safety at road intersections and enable congestion avoidance. However, detailed knowledge about the wireless propagation channel is needed for the development and realistic assessment of V2V communication systems. We present a novel geometry-based stochastic MIMO channel model with support for frequencies in the band of 5.2-6.2 GHz. The model is based on extensive high-resolution measurements at different road intersections in the city of Berlin, Germany. We extend existing models, by including the effects of various obstructions, higher order interactions, and by introducing an angular gain function for the scatterers. Scatterer locations have been identified and mapped to measured multi-path trajectories using a measurement-based ray tracing method and a subsequent RANSAC algorithm. The developed model is parameterized, and using the measured propagation paths that have been mapped to scatterer locations, model parameters are estimated. The time variant power fading of individual multi-path components is found to be best modeled by a Gamma process with an exponential autocorrelation. The path coherence distance is estimated to be in the range of 0-2 m. The model is also validated against measurement data, showing that the developed model accurately captures the behavior of the measured channel gain, Doppler spread, and delay spread. This is also the case for intersections that have not been used when estimating model parameters.Comment: Submitted to IEEE Transactions on Vehicular Technolog

The Existential Crisis of the New World Digital: How Centralization Stole the Internet and What Blockchain Technology Could Offer the User

The thesis examines how the technology of blockchain can be used as governing mechanism to create a more democratic digital space. Starting with an overview of internet history, this section contextualizes the terms “sterile” and “generative” technology. This tension is a constant in internet history with blockchain being the “generative” pull away from the more “sterile” server stack model of big tech. Both current state and corporate governances are built off a more centralized model, however with blockchain technology, democracy, as well as company structure is being re-examined. Ideas such as stakeholder capitalism and open democracy are a similarly “generative” model as opposed to the more centralized “sterile” approach of more traditional democracies. With a space that humans communicate also comes ethics that define the morals and norms of the space. In a more centralized model, utilitarian and deontological approaches to ethics have provided a groundwork for a just society prior to the computer. However, the computer, acknowledging the multiplicity of “being,” requires an approach to ethics that is more decentralized than these current ethical models. Existentialism, through Sartre’s examination of “being,” exposes the flaws in centralized ethics through the acknowledgment of human “beings” as being in a constant flux with their “being” being defined by a “being” outside of their own existence; “the Other.” This sets the stage to delve into the benefit of a computer system functioning more off a decentralized approach like a blockchain system. Decentralized Autonomous Organizations (DAO) directly tests blockchain as a governing system. Supported by the ethics of existential philosophy, blockchain, like state governance can be justified as a genuine form of governance. While there are drawbacks to blockchain the technology holds a lot of potential of creating the most democratic space in the history of the world

Statistical Modeling and Estimation of Censored Pathloss Data

Pathloss is typically modeled using a log-distance power law with a large-scale fading term that is log-normal. However, the received signal is affected by the dynamic range and noise floor of the measurement system used to sound the channel, which can cause measurement samples to be truncated or censored. If the information about the censored samples are not included in the estimation method, as in ordinary least squares estimation, it can result in biased estimation of both the pathloss exponent and the large scale fading. This can be solved by applying a Tobit maximum-likelihood estimator, which provides consistent estimates for the pathloss parameters. This letter provides information about the Tobit maximum-likelihood estimator and its asymptotic variance under certain conditions.Comment: 4 pages, 3 figures. Published in IEEE Wireless Communication Letter

Exploring the Potential of the Web-Based Virtual World of Second Life to Improve Substance Abuse Treatment Outcomes

Provides an overview of Second Life, an Internet-based virtual world, and summarizes discussions among addiction recovery experts about integrating virtual reality into behavioral treatment as a way to teach patients new responses to real environments

A Search for baryon number violation by two units at the Super-Kamiokande detector

Baryon number B appears to be a conserved quantity in the Standard Model of particle physics, though there are compelling theoretical reasons to believe it isn't. This thesis describes searches for processes that violate B by two units with the Super-Kamiokande experiment. Two types of searches are performed. One is the simultaneous decay of two bound nucleons to pions (dinucleon decay), encompassing the modes ^16O() → ^14C ^+^+, ^16O() → ^14N ^+^0, and ^16O() → ^14O ^0^0. The second is a search for a neutron transforming into an antineutron, or neutron-antineutron oscillation → n̄. This thesis uses the full dataset across four Super-Kamiokande detector periods from April 1996 to March 2015, comprising 4972.4 livetime days (307 kiloton-years). Monte Carlo simulations of the signal processes and their background from atmospheric neutrino interactions are used to estimate signal efficiency, expected background, and their associated uncertainties. Both multivariate analyses and simple kinematical cuts are applied in these searches. This is the first search for dinucleon decay to pions in oxygen. The search for → n̄ entails some important updates from a previous search at Super-Kamiokande, mainly increased exposure and an improved model of pion interactions. For all but the single mode ^16O() → ^14O ^0^0, it is found that a boosted decision tree multivariate method gives the best signal-background separation, while for ^16O() → ^14O ^0^0 a set of simple kinematic cuts suffice. In each mode investigated, no signal excess was observed, and all data are consistent with atmospheric neutrino background. In the absence of evidence for any signal process, lower lifetimes are set at the 90% confidence level. For dinucleon decay, the limits are _→^+^+ > 7.2 × 10^31 years, _→^+^0 > 1.7 × 10^32 years, and _→^0^0 > 4.0 × 10^32 years. These limits are about two orders of magnitude more stringent than those set by previous searches for dinucleon decay in iron. For → n̄, the limit for bound neutrons is _bound > 2.4 × 10^32 years, corresponding to a free neutron lifetime _free > 3.8 × 10^8 s. This is comparable with previous results from Super-Kamiokande and other experiments

EXPORT ENHANCEMENT STRATEGIES FOR SMALL AND MEDIUM RURAL AND AGRICULTURAL FIRMS

Literature reports that small and medium firms face greater difficulty in obtaining the necessary export market information and in obtaining financing than do larger firms. Accordingly, the United States has many export promotion and enhancement services, but there is little documentation on the impacts of these services on small and medium rural and agricultural firms. The objectives of this project were to 1) analyze the export assistance needs of small and medium rural and agricultural firms operating in the Northern Plains region at different stages of the export or internationalization process, 2) identify available export assistance and promotion services offered at the federal and state levels to meet the needs of these firms, and 3) identify factors that may increase the effectiveness of export assistance programs. The primary assistance these firms wanted from the government was help in documenting their exports. The primary reasons firms did not seek government assistance were a lack of knowledge of the service and the service is not useful. The most often used non-government information sources were trade or industry associations and banks. Accordingly, policy makers should emphasize programs that complement efforts of private organizations and that target the needs and interests of the firms.export, rural, agriculture, export assistance, Northern Plains, government, Community/Rural/Urban Development, International Development,