On the structure and spectrum of classical two-dimensional clusters with a logarithmic interaction potential

We present a numerical study of the effect of the repulsive logarithmic inter-particle interaction on the ground state configuration and the frequency spectrum of a confined classical two-dimensional cluster containing a finite number of particles. In the case of a hard wall confinement all particles form one ring situated at the boundary of the potential. For a general r^n confinement potential, also inner rings can form and we find that all frequencies lie below the frequency of a particular mode, namely the breathing-like mode. An interesting situation arises for the parabolic confined system(i.e. n=2). In this case the frequency of the breathing mode is independent of the number of particles leading to an upper bound for all frequencies. All results can be understood from Earnshaw's theorem in two dimensions. In order to check the sensitivity of these results, the spectrum of vortices in a type II superconductor which, in the limit of large penetration depths, interact through a logarithmic potential, is investigated.Comment: 11 pages, 6 figure

Global Assimilation of Loon Stratospheric Balloon Observations and Their Trajectories Relative to Tropical Waves

Project Loon has an overall goal of providing worldwide internet coverage using a network of long-duration super-pressure balloons. Beginning in 2013, Loon has launched over 1600 balloons from multiple tropical and middle latitude locations. These GPS tracked balloon trajectories provide lower stratospheric wind information over the oceans and remote land areas where traditional radiosonde soundings are sparse, thus providing unique coverage of lower stratospheric winds. To fully investigate these Loon winds we: 1) compare the Loon winds to winds produced by a global data assimilation system (DAS: NASA GEOS) and 2) assimilate the Loon winds into the same comprehensive DAS. During May through December 2016 Loon balloons were often able to remain near the equator by selectively adjusting the Loon altitude. Our results based on global wind analyses show that the expected mean poleward motion from the Brewer-Dobson circulation can be circumvented by vertically adjusting the Loon altitudes with the phasing with the meridional wind of equatorial Rossby waves, allowing the Loon balloons to remain in the tropics

Active Learning Strategies for Teaching Lean Thinking

Active learning is a method of designing instruction so that classroom students are actively involved in learning concepts and content. Instead of casting students into the role of passive listener, active learning techniques strive to engage learners in reading, writing, discussing and doing things to connect the learners to the material. The Lean Aerospace Initiative sponsored the development of a foundational LAI Lean Academy® course about lean concepts. The class is targeted for an audience with little or no experience in lean concepts and it was designed with a learner-centered focus using active learning techniques. Several strategies used successfully in this class will be described in this paper, specifically: plant tours, the supply chain puzzle, mechanical assembly for lean engineering and interviews/out briefs. Results from student feedback indicate that class participants enjoy the active learning segments of the class much better than modules that are mostly lecture-based

A Lightweight Regression Method to Infer Psycholinguistic Properties for Brazilian Portuguese

Psycholinguistic properties of words have been used in various approaches to Natural Language Processing tasks, such as text simplification and readability assessment. Most of these properties are subjective, involving costly and time-consuming surveys to be gathered. Recent approaches use the limited datasets of psycholinguistic properties to extend them automatically to large lexicons. However, some of the resources used by such approaches are not available to most languages. This study presents a method to infer psycholinguistic properties for Brazilian Portuguese (BP) using regressors built with a light set of features usually available for less resourced languages: word length, frequency lists, lexical databases composed of school dictionaries and word embedding models. The correlations between the properties inferred are close to those obtained by related works. The resulting resource contains 26,874 words in BP annotated with concreteness, age of acquisition, imageability and subjective frequency.Comment: Paper accepted for TSD201

Enhancing Faculty Competency in Lean Thinking Bodies of Knowledge

The Lean Aerospace Initiative’s (LAI) Educational Network (EdNet) established in 2002 is comprised of 32 universities who share a common interest to collaborate on developing and deploying curriculum for teaching lean six sigma fundamentals. Supported by a small staff centered at MIT, collaborating faculty have developed a week-long LAI Lean Academy® course, and delivered it to multiple audiences on-campus and in industry and government. The topics of the course map to many CDIO syllabus topics, and the pedagogy and assessment methods have borrowed on the CDIO knowledge base. This paper reports on this undertaking and on the extent to which it has contributed to developing faculty competency for teaching Lean Thinking in engineering and management. Results from this study reveal that instructors have significantly improved their competency to teach Lean Thinking during their affiliation with the LAI EdNet. On average, the instructors’ proficiency in twelve Lean Enterprise knowledge areas has increased a full level, from 3.2 to 4.2, on the CDIO Syllabus MIT Activity Based Proficiency Scale. The instructors report that collaboration on conceiving, developing and implementing the curriculum has been the most valuable EdNet activity for increasing their competency

Active Learning Strategies for Teaching Lean Thinking

Active learning is a method of designing instruction so that classroom students are actively involved in learning concepts and content. Instead of casting students into the role of passive listener, active learning techniques strive to engage learners in reading, writing, discussing and doing things to connect the learners to the material. The Lean Aerospace Initiative sponsored the development of a foundational LAI Lean Academy® course about lean concepts. The class is targeted for an audience with little or no experience in lean concepts and it was designed with a learner-centered focus using active learning techniques. Several strategies used successfully in this class will be described in this paper, specifically: plant tours, the supply chain puzzle, mechanical assembly for lean engineering and interviews/out briefs. Results from student feedback indicate that class participants enjoy the active learning segments of the class much better than modules that are mostly lecture-based