Diversification Across Mining Pools: Optimal Mining Strategies under PoW

Mining is a central operation of all proof-of-work (PoW) based cryptocurrencies. The vast majority of miners today participate in "mining pools" instead of "solo mining" in order to lower risk and achieve a more steady income. However, this rise of participation in mining pools negatively affects the decentralization levels of most cryptocurrencies. In this work, we look into mining pools from the point of view of a miner: We present an analytical model and implement a computational tool that allows miners to optimally distribute their computational power over multiple pools and PoW cryptocurrencies (i.e. build a mining portfolio), taking into account their risk aversion levels. Our tool allows miners to maximize their risk-adjusted earnings by diversifying across multiple mining pools which enhances PoW decentralization. Finally, we run an experiment in Bitcoin historical data and demonstrate that a miner diversifying over multiple pools, as instructed by our model/tool, receives a higher overall Sharpe ratio (i.e. average excess reward over its standard deviation/volatility).Comment: 13 pages, 16 figures. Presented at WEIS 201

Physical engagement in nursery rhyming games in oral, print, and digital mediums: Data matrix

The first children’s video game called Mixed up Mother Goose was created by Roberta Williams in 1987. This game was created for a desktop. Today, many children’s games exist on a range of digital platforms. While these platforms offer different types of interactions for engagement and learning, many of these interactions are limited to tapping, dragging and clicking. Current studies have shown that physical interaction is important for young children’s development. Traditionally, nursery rhymes have been this source of physical interaction to engage children in the process of learning. This study looks at the physical engagement of children with nursery rhymes in oral, print and digital mediums. Engagement in oral medium consists of learning nursery rhymes through the movement of the body such as action rhymes and finger plays. Engagement in print medium consists of learning nursery rhymes through interactive books that include movable books, puppet books and sound books. Digital medium, including platforms such as touchscreen devices and laptops, continue to evolve from tap and click games to increased physical engagement of children. Although digital medium is a new phenomenon, it is following a similar evolution as print and oral mediums. Digital medium is increasingly engaging children with interactive play. As part of a larger project, this research collects information and provides a matrix that identifies the attributes of physical engagement employed by these three mediums.Undergraduat

Digital Current-Control Schemes

The paper is about comparing the performance of digital signal processor-based current controllers for three-phase active power filters. The wide use of nonlinear loads, such as front-end rectifiers connected to the power distribution systems for dc supply or inverter-based applications, causes significant power quality degradation in power distribution networks in terms of current/voltage harmonics, power factor, and resonance problems. Passive LC filters (together with capacitor banks for reactive power compensation) are simple, low-cost, and high-efficiency solution

Direct torque control for dual three-phase induction motor drives

A direct torque control (DTC) strategy for dual three-phase induction motor drives is discussed in this paper. The induction machine has two sets of stator three-phase windings spatially shifted by 30 electrical degrees. The DTC strategy is based on a predictive algorithm and is implemented in a synchronous reference frame aligned with the machine stator flux vector. The advantages of the discussed control strategy are constant inverter switching frequency, good transient and steady-state performance, and low distortion of machine currents with respect to direct self-control (DSC) and other DTC schemes with variable switching frequency. Experimental results are presented for a 10-kW DTC dual three-phase induction motor drive prototype

Morphological strategies training: The effectiveness and feasibility of morphological strategies training for students of English as a foreign language with and without spelling difficulties

The aim of this study was primarily to investigate the effects of morphological strategies training on students with and without spelling difficulties in English as a foreign language (EFL), but also to assess the feasibility of morphological strategies training in a classroom context. The intervention was piloted in the sixth grade of a Greek primary school: 23 Greek-speaking students, aged 11-12, were assigned to the treatment group receiving explicit teaching on inflectional and derivational morphemic patterns of English words. The control group, composed of 25 Greek-speaking students of the same age, attending a different classroom of the same school, was taught English spelling in a conventional (visual-memory based) way. Both quantitative and qualitative methods were employed to gain insights: a pre- and post-test, an observation schedule, a student questionnaire and a teacher interview. The pre- and post-test results indicated that the metamorphological training yielded specific effects on targeted morpheme patterns. The same results were obtained from a sub-group of nine poor spellers in the treatment group, compared to a sub-group of six poor spellers in the control one. The observation data revealed that the metamorphological training promoted students' active participation and the questionnaire data indicated that students got satisfaction from their training. Finally, interview data highlighted that teachers considered the intervention as a feasible way of improving students' morphological processing skills in spelling

Language awareness issues and teachers’ beliefs about language learning in a Greek EFL context

The present study aimed at investigating the role of language awareness from the teachers’ perspective as well as its relationship with other aspects of EFL teacher knowledge. The study was designed and conducted with the aim of providing an account of the issues related to EFL teachers’ language awareness and their beliefs about how students learn a foreign language. Questionnaires were distributed to a total of 150 EFL teachers employed in public primary and secondary schools in Northern Greece. The findings indicated that the participants were conscious to a certain degree of the need for raising language awareness in the EFL classroom and developing students’ language learning strategies

CLIL Approach in Primary Education: Learning about Byzantine Art and Culture through a Foreign Language

The purpose of the present study is to provide insights into experimental research on Content and Language Integrated Learning (CLIL) for developing English as a Foreign Language (EFL) skills and aspects of Byzantine history and culture in the context of Greek primary education. It aims at a) developing a CLIL project with a focus on Byzantine and post Byzantine history and culture for 6th primary school students; b) investigating the effects of CLIL on students’ skills performance after a total of 30 teaching sessions intervention; c) identifying whether CLIL instruction develops a more positive attitude towards FL and content learning. A multimodal and multisensory learning environment was created in order to support and enhance language skills and content knowledge. In such a context, students were encouraged to use language creatively through getting involved in communicative, problem-solving and inquiry-based activities. The positive effects of the project were indicated, particularly on students’ communicative skills. Also gains were recorded in relation to students’ enhancement of content knowledge and skills, as well their positive attitude towards FL and content learning

“El mundo visto desde miradas diferentes”: un proyecto que integra contenido y lenguaje para aprendices de inglés como lengua extranjera en primaria

This paper presents the design, implementation, and evaluation of a project entitled “It’s the same world through different eyes,” which was based on the principles of the Content and Language Integrated Learning (CLIL) approach and was piloted with 4th grade primary school students (between 9 and 10 years of age). More specifically, we employed a dual-focused approach, focusing equally on EFL (English as a foreign language) and content development. For the purpose of the project, we designed a mini-syllabus with the stories being at the core of the design. The objectives of the project were to a) develop the students’ receptive and productive skills in EFL), b) develop their sensitivity towards diversity, and c) enhance their citizenship awareness. Students were provided with opportunities to express themselves verbally and nonverbally, and participate in a variety of creative activities in a multimodal teaching context. The findings of project indicated students’ improvement regarding both their receptive and productive skills in the target language, and the development of children’s citizenship awareness, and their sensitivity towards diversity.Este manuscrito presenta el diseño, la realización y la evaluación de un proyecto titulado “El mundo visto desde miradas diferentes” para aprendices de inglés como lengua extranjera en primaria, basado en los principios de integración de contenido y lengua para el aprendizaje (CLIL) piloteado con estudiantes de cuarto grado de escuela primaria (entre 9 y 10 años de edad). Se utilizó un enfoque dual-enfocado, concentrándonos igualmente en lengua inglesa y desarrollo de contenidos. Se diseñó un mini-syllabus basado en historias. Los objetivos del proyecto fueron: a) desarrollar las habilidades receptivas (escucha y lectura) y productivas (oral y escrita) de los estudiantes en inglés como lengua extranjera, b) desarrollar su sensibilidad hacia la diversidad, c) realzar su conciencia ciudadana. A los estudiantes se les brindó la oportunidad de expresarse verbalmente y no verbalmente, y de participar en una variedad de actividades creativas en un contexto de enseñanza multimodal. Los resultados indicaron mejoramiento de las habilidades receptivas como productivas de los estudiantes en la lengua meta y el desarrollo de la conciencia ciudadana en los niños y su sensibilidad hacia la diversidad