Scikit-Multiflow: A Multi-output Streaming Framework

Scikit-multiflow is a multi-output/multi-label and stream data mining framework for the Python programming language. Conceived to serve as a platform to encourage democratization of stream learning research, it provides multiple state of the art methods for stream learning, stream generators and evaluators. scikit-multiflow builds upon popular open source frameworks including scikit-learn, MOA and MEKA. Development follows the FOSS principles and quality is enforced by complying with PEP8 guidelines and using continuous integration and automatic testing. The source code is publicly available at https://github.com/scikit-multiflow/scikit-multiflow.Comment: 5 pages, Open Source Softwar

A quantum-like model for complementarity of preferences and beliefs in dilemma games

We propose a formal model to explain the mutual influence between observed behavior and subjects' elicited beliefs in an experimental sequential prisoner's dilemma. Three channels of interaction can be identified in the data set and we argue that two of these effects have a non-classical nature as shown, for example, by a violation of the sure thing principle. Our model explains the three effects by assuming preferences and beliefs in the game to be complementary. We employ non-orthogonal subspaces of beliefs in line with the literature on positive-operator valued measure. Statistical fit of the model reveals successful predictions

Employed Desistance: Identifying Best Employment-Focused Interventions and Practices for Gang Desistance

This study examined those employment-focused interventions (services, programming, mentorship, other supports) most effective in supporting an individual’s desistance from gang involvement. Utilizing a qualitative approach (interviews, document analysis and nonparticipant observation), this study engaged with individuals and organizations involved in the critical work of gang desistance to learn what makes their practices most effective. The criticality of gang desistance work lies in its efforts to address the thousands of lives continually lost each year as a result of gang-involvement and activity. Where gangs exist in cities, towns and communities across the country (and world, for that matter), the approaches of demonization, marginalization and suppression continue as the overwhelming response to gangs and gang activity. This study highlighted the individuals and organizations offering an alternative, employment-focused approach built on peer- and community-based efforts founded on inclusion and empowerment. Through the data collection, this study intended to identify and detail the practices of the research participants and why they are effective. Beginning with a review of available research within the field of gang desistance, an understanding of the evolving theories of the phenomenon of one desisting from gang involvement were explored, followed by an exploration of why individuals join gangs, the impacts of gang involvement, what prompts gang members to desist, and those interventions most supportive of this desistance. With an emphasis on service providers and leaders with the lived experience of gang desistance, as well as organizations dedicated to gang desistance work, the themes and evidence that emerged from the data collection provided deeper insights into how the process of desisting from gang involvement can be most effectively supported and realized. The outcome of this research pointed to several components of the work of gang desistance that make it most effective. These components focused on the desisting individual and the internal and external elements that both prompted and help maintained their desistance; the types of interventions most conducive to supporting a desisting individual––especially those focused on the individual’s identity desistance and self-efficacy; and, finally, those qualities of those service providers and organizations who provided these interventions and what made them impactful and effective. The findings of this study revealed that there are models, practices and other elements to support individuals toward effectively desisting from gang involvement. The findings also revealed the challenging and dynamic nature of the phenomenon of gang desistance––both for those desisting and those supporting them. Resulting from this nature of the work and the still developing field of gang desistance studies, these findings also offered areas of focus for future research toward a stronger understanding of the process of gang desistance, and, more importantly, the development and implementation of effective gang desistance concepts and practices

Electro-optomechanical equivalent circuits for quantum transduction

Using the techniques of optomechanics, a high-$Q$ mechanical oscillator may serve as a link between electromagnetic modes of vastly different frequencies. This approach has successfully been exploited for the frequency conversion of classical signals and has the potential of performing quantum state transfer between superconducting circuitry and a traveling optical signal. Such transducers are often operated in a linear regime, where the hybrid system can be described using linear response theory based on the Heisenberg-Langevin equations. While mathematically straightforward to solve, this approach yields little intuition about the dynamics of the hybrid system to aid the optimization of the transducer. As an analysis and design tool for such electro-optomechanical transducers, we introduce an equivalent circuit formalism, where the entire transducer is represented by an electrical circuit. Thereby we integrate the transduction functionality of optomechanical systems into the toolbox of electrical engineering allowing the use of its well-established design techniques. This unifying impedance description can be applied both for static (DC) and harmonically varying (AC) drive fields, accommodates arbitrary linear circuits, and is not restricted to the resolved-sideband regime. Furthermore, by establishing the quantized input-output formalism for the equivalent circuit, we obtain the scattering matrix for linear transducers using circuit analysis, and thereby have a complete quantum mechanical characterization of the transducer. Hence, this mapping of the entire transducer to the language of electrical engineering both sheds light on how the transducer performs and can at the same time be used to optimize its performance by aiding the design of a suitable electrical circuit.Comment: 30 pages, 9 figure

On absolute Galois splitting fields of central simple algebras

A splitting field of a central simple algebra is said to be absolute Galois if it is Galois over some fixed subfield of the centre of the algebra. The paper provides an existence theorem for such fields over global fields with enough roots of unity. As an application, all twisted function fields and all twisted Laurent series rings over symbol algebras (or p-algebras) over global fields are crossed products. A closely related statement holds for division algebras over Henselian valued fields with global residue field. The existence of absolute Galois splitting fields in central simple algebras over global fields is equivalent to a suitable generalization of the weak Grunwald-Wang Theorem, which is proved to hold if enough roots of unity are present. In general, it does not hold and counter examples have been used in noncrossed product constructions. This paper shows in particular that a certain computational difficulty involved in the construction of explicit examples of noncrossed product twisted Laurent series rings can not be avoided by starting the construction with a symbol algebra.Comment: 12 pages (A4); to appear in J. Number Theory (2007

Pulsar Noise Processes and Emission Physics

Precision pulsar timing can be used to study many different astrophysically interesting phenomena, from the emission mechanism of pulsars to the detection of nanohertz gravitational waves. These analyses span topics such as studying the single pulses of pulsars and analyzing years of pulsar timing data from pulsar timing arrays (PTAs). Single-pulse studies allow us to glean information on the emission physics of pulsars on their shortest timescales, while PTA observations of millisecond pulsars (MSPs) allow us to not only study the pulsars themselves, but also probe the interstellar medium (ISM) and constrain the noise in the data for precision pulsar timing experiments. To study the emission properties of pulsars, we compiled a large population of single pulses from three rotating radio transients (RRATs), from which we detect sporadic, but periodic pulsations and whose emission mechanisms remain largely unknown. Our study found that the average spectral indices of these RRATs is flatter than most pulsars, with a power-law index of α = −0.9, but that the distribution of single-pulse spectral indices is large. We also find that the single-pulse flux distributions of these three RRATs generally follow a log-normal distribution, suggesting the detected radio emission is not due to giant pulses. Further we find that single-pulse flux is not correlated with the wait-time between pulses, and thus is not produced by mechanisms such as the storage and release of energy in the pulsar magnetosphere. We then analyze multi-hour continuous observations of seven MSPs in the North American Nanohertz Observatory for Gravitational Wave (NANOGrav) PTA to characterize the ISM along their lines-of-sight. These unique observa- tions allowed us to place some of the best limits on the scintillation bandwidth and timescale for these MSPs, some for the first time, and show that the root mean square (rms) noise due to scattering in these MSPs is \u3c 50 ns. We further showed that, as expected, the dispersion measure (DM) of these MSPs does not vary on ∼ hour long timescales, and that the timing precision of these MSPs does not decrease if the observations are not contiguous, as expected for observations by telescopes like the Canadian Hydrogen Intensity Mapping Experiment. Finally, we explore the covariances between various radio frequency-dependent parameters in pulsar timing models and how they contribute to the overall noise budget of the PTA. To do this, we developed the Pulsar Signal Simulator Python package and use it to generate simulated data sets for three NANOGrav MSPs. We find a clear correlation between the mean injected scattering timescale and the spread in the recovered DM value, with larger scattering timescales corresponding to larger spreads. However, we find that this covariance, while important to quantifying the noise budget of the PTA, does not affect the timing precision of the simulated MSPs

Franco-American Newspapers and Periodicals in the Northeast: An Inventory

Franco-American newspapers and periodicals occupy an overlapping space between primary and secondary literature, and their shadow looms large over the collective body of historic Franco-American sources. Their significance to the Franco-American community is hard to overstate. These periodical publications complicate issues of identity in the U.S. Northeast and are an integral part of Québec history itself. This article details current work to inventory newspaper and periodical titles (currently over 400) and makes accessible our collectively built, evolving inventory of Franco-American newspapers. Les journaux et périodiques franco-américains occupent un espace entre la littérature primaire et la littérature secondaire, et leur ombre plane sur le corpus collectif des sources historiques franco-américaines. Leur importance pour la communauté franco-américaine est difficile à surestimer. Ces publications périodiques compliquent les questions d’identité dans le Nord-Est américain et font partie intégrante de l’histoire même du Québec. Cet article détaille les travaux en cours pour recenser les titres de journaux et de périodiques (présentement plus de 400) et rend accessible notre inventaire construit collectivement des journaux franco-américains