A study of user experiences and network analysis on anonymity and traceability of bitcoin transactions

This paper investigates the anonymity of bitcoin transactions and significance of awareness of the technology by bitcoin users, alongside their experiences in tracing transactions. Bitcoin enables users to carry out transactions anonymously with the virtual currency without unveiling where the real-world source of the income has come from. These transactions may occur without revealing locations or any personal identifiable information of the person who is sending or receiving bitcoins. While there are existing surveys which test bitcoin users’ awareness of the technology, they do not focus on bitcoin users’ own experience using the technology in terms of tracing transactions and use of anti-forensic tools to increase the level of anonymity. This paper reports significance of users’ opinions on traceability and anonymity of bitcoin transactions and compares users’ viewpoints collected from a survey with experimental findings observed using network analysis tools

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Contribuição ao conhecimento da ictiofauna do Manguezal de Cacha Pregos, Ilha de Itaparica, Baía de Todos os Santos, Bahia Contribution to knowledge of ichthyofauna of Mangrove Cacha Pregos, Itaparica island, Todos os Santos bay, Bahia

<abstract language="eng">A check-list of fishes collected in a mangrove in Cacha Pregos, south of ltaparic Island, State of Bahia, Brazil (about 13o07'S,38o48'W) from 1988-1989 and 1991-1992 is presented. Fifteen orders, 46 families and 85 species (Teleostei except one Chondrichthyes) were identified, represented specimens whose adults live in different marine ecossystems