1,969 research outputs found
Deformation and Aerodynamic Performance of a Ram-Air Wing
No full textRam-air wings form an ever increasing market of soft fabric, air inflated wings. They are primairily used in air sports such as parachuting, paragliding and kiting. Ram-air kites may also be used for electric power generation by letting the kite pull a cable from a drum that is connected to a generator. An example if this principle is the Laddermill concept. But since ram-air wings are flexible by nature they will deform and depart from their intended design shape when they are loaded by aerodynamic forces. These deformations generally affect the performance of the wings adversely. Kites with a higher lift-to-drag ratio on the Laddermill could mean a direct increase of the energy produced per square meter of kite. Besides this benefit for the Laddermill there is a huge, world-wide market of parachuting, paragliding and kiting that can benefit from more research and a better understanding of the deformation and aerodynamic performance of ram-air wings. The goals of this thesis are to be able to point out where a ram-air kite departs from the intended design shape, to investigate how well the kite performs, to understand how the deformations affect the airflow and to make suggestions for possible improvements of the design. Since little has been published about these subjects this report will most of all form a basis for further research. This report presents a method to analyse the shape and the aerodynamics of a ram-air kite. The kite is tested in the windtunnel. Its 3D shape is captured using two techniques: photogrammetry and laser scanning. Using the geometry data the structural deformation of the wing is dissected. With computational fluid dynamics the aerodynamics of the deformed shape is analyzed. An extra result of this study is the comparison of photogrammetry and laser scanning in terms of their suitability to capture the 3D shape of the ram-air kite. A number of interesting deformations and flow features were found on the ram-air wing: - Theoretically the bumps (ballooning) and grooves on a ram-air wing hinder the spanwise flow on a 3-dimensional wing, but in practise this effect is only visible on small parts of the upper surface. - The pull of the suspension lines on the under surface and the internal construction of the wing make the upper surface of the wing deform. This results in a decrease of the upper surface curvature, especially near the nose. This curvature decrease causes a loss of lift of at least 5%. - Because the flat, 2-dimensional fabric is inflated into a 3-dimensional shape the fabric wrinkles. The wrinkles continue from the top and bottom surface into the ribs that internally connect and support the top and bottom surface. On average these wrinkles shorten the ribs in chordwise direction by 3.5%. This decreases the surface area of the wing and it makes the ribs effectively thicker. Many more details became visible with the thorough analysis of the wing’s shape. The conclusion is that the performance of the ram-air wing can be improved by changing these details. The photogrammetry measuring technique gave better results than laser scanning and is very suitable tool to make these details visible. It allows a designer to identify where the real flying shape deviates from the design shape. This can help kite designers and designers of other ram-air wings to reverse-Aerospace Engineerin
Great Expectatrics: Great Papers, Great Journals, Great Econometrics
No full textThe paper discusses alternative Research Assessment Measures (RAM), with an emphasis on the Thomson Reuters ISI Web of Science database (hereafter ISI). The various ISI RAM that are calculated annually or updated daily are defined and analysed, including the classic 2-year impact factor (2YIF), 5-year impact factor (5YIF), Immediacy (or zero-year impact factor (0YIF)), Eigenfactor score, Article Influence, C3PO (Citation Performance Per Paper Online), h-index, Zinfluence, and PI-BETA (Papers Ignored - By Even The Authors). The ISI RAM data are analysed for 8 leading econometrics journals and 4 leading statistics journals. The application to econometrics can be used as a template for other areas in economics, for other scientific disciplines, and as a benchmark for newer journals in a range of disciplines. In addition to evaluating high quality research in leading econometrics journals, the paper also compares econometrics and statistics, alternative RAM, highlights the similarities and differences in alternative RAM criteria, finds that several ISI RAM capture similar performance characteristics for the leading econometrics and statistics journals while the new PI-BETA criterion is not highly correlated with any of the other ISI RAM, and hence conveys additional information regarding ISI RAM, highlights major research areas in leading journals in econometrics, and discusses some likely future uses of RAM.Research assessment measures, impact factors, Immediacy, Eigenfactor score, Article influence, h-index, C3PO, Zinfluence, PI-BETA
Scientometric portrait of Ram Gopal Rastogi
No full textPublication productivity of Indian scientist (R.G. Rastogi) has been documented.
Scientometric analysis of 312 papers by Ram Gopal Rastogi published during 1954 to 1992 in various domains: (a) Luni -solar activity and quiet -time E & F- region (57); (b) Equatorial electric field and low and mid latitude iof:osphere (78); (c) Ionospheric E- region irregularities (19); (dj Ionospheric F- region irregularities (32); and (e) Magnetic disturbance effects on the equatorial low and mid latitude ionosphere (23) were analysed. Interdomainery contents and of the number of papers: a+b were 36; b+c and b+d were 20 each; b+e were 16;. c+e were 5; a+e were 3; d+e were 2; and a+d had only one publication. Highest collaborations were with H. Chandra (61), M.R. Deshpande (42), and G. Sethia (19) out of his total 97 collaborators. His highest productivity was during 1978 with 28 papers followed by 19 papers during 1977. The core journals preferred by him for publishing papers were: Indian Journal of Radio & Space Physics, India, and Journal of Atomic & Terrestrial Physics, UK (59 each), followed by Proceedings of the Indian Academy of Sciences, India (34). Most prolific title keywords with their frequencies were: Ionosphere (92); Equatorial (61); F-region (53); Equatorial electrojet region (40), and Magnetic equator (30)
Great Expectatrics: Great Papers, Great Journals, Great Econometrics
No full textThe paper discusses alternative Research Assessment Measures (RAM), with an emphasis on the Thomson Reuters ISI Web of Science database (hereafter ISI). The various ISI RAM that are calculated annually or updated daily are defined and analysed, including the classic 2-year impact factor (2YIF), 5-year impact factor (5YIF), Immediacy (or zero-year impact factor (0YIF)), Eigenfactor score, Article Influence, C3PO (Citation Performance Per Paper Online), h-index, Zinfluence, and PI-BETA (Papers Ignored - By Even The Authors). The ISI RAM data are analysed for 8 leading econometrics journals and 4 leading statistics journals. The application to econometrics can be used as a template for other areas in economics, for other scientific disciplines, and as a benchmark for newer journals in a range of disciplines. In addition to evaluating high quality research in leading econometrics journals, the paper also compares econometrics and statistics, alternative RAM, highlights the similarities and differences in alternative RAM criteria, finds that several ISI RAM capture similar performance characteristics for the leading econometrics and statistics journals while the new PI-BETA criterion is not highly correlated with any of the other ISI RAM, and hence conveys additional information regarding ISI RAM, highlights major research areas in leading journals in econometrics, and discusses some likely future uses of RAM.Research assessment measures; impact factors; Immediacy; Eigenfactor score; Article influence; h-index; C3PO; Zinfluence; PI-BETA
Population automation: An interview with Wikipedia bot pioneer Ram-Man
No full textSoftware robots (“bots”) play a major role across the Internet today, including on Wikipedia, the world’s largest online encyclopedia. Bots complete over 20 percent of all edits to the project, yet often their work goes unnoticed by other users. Their initial integration onto Wikipedia was not uncontested and highlighted the opposing philosophies of “inclusionists” and “deletionists” who influenced the early years of the project. This paper presents an in-depth interview with Wikipedia user Ram-Man, an early bot operator on the site and creator or the rambot, the first mass-editing bot. Topics discussed include the social and technical climate of early Wikipedia, the creation of bot policies and bureaucracy, and the legacy of rambot and Ram-Man’s work
Steady-State Solver for a Ram-Air Kite Aeroelastic Model Based on Dynamic Relaxation
No full textWe present a computationally efficient steady-state solution method to model the aeroelastic deformation of a ram-air kite for airborne wind energy applications. The kite’s weight in comparison to the aerodynamic forces is small which justifies a quasi-steady analysis, neglecting gravitational and inertial force effects [1]. The approach is suitable to efficiently determine the deformed configuration of a ram-air kite for design and optimization purposes as found in [2]. Because of the expected large deformations and changes in the flow field, fluid-structure interaction has to be taken into account in the analysis.Wind Energ
Night-Time Stories from The Panchatantra
No full textSimilar to Arora's 101 Moral Stories of Grandpa, this hardbound book with dust-jacket has 100 pages. The T of C on 6 lists fifteen numbered stories. This book is remarkable for offering a large picture on almost every page. New to me is The Sparrows & the Tusker (51). An elephant breaks off a limb and unwittingly destroys a nest. The sparrows get help from a woodpecker, a fly, and a frog, Together they lull the elephant, blind him by pecking out his eyes, and mislead him into a deep pit he mistakes for a water-hole. It is nice to meet old friends from the Panchatantra and Kalila and Dimna tradition, and I enjoy Ram-Lakshman's art. One of the best images here is that of the lion springing into the well as the hare runs away (99). The dust-jacket is glued to the covers.This is a hardbound book (hard cover)This book has a dust jacket (book cover)Retold by Reinu Bhano
Using low latency storage to improve RDF store performance
No full textResource Description Framework (RDF) is a flexible, increasingly popular data model that allows for simple representation of arbitrarily structured information. This flexibility allows it to act as an effective underlying data model for the growing Semantic Web. Unfortunately, it remains a challenge to store and query RDF data in a performant manner, with existing stores struggling to meet the needs of demanding applications: particularly low latency, human-interactive systems. This is a result of fundamental properties of RDF data: RDF’s small statement size tends to engender large joins with a lot of random I/O, and its limited structure impedes the generation of compact, relevant statistics for query optimisation.This thesis posits that the problem of performant RDF storage can be effectively mitigated using in-memory storage, thanks to RAM’s extremely high throughput and rapid random I/O relative to disk. RAM is rapidly reducing in cost, and is finally reaching the stage where it is becoming a practical medium for the storage of substantial databases, particularly given the relatively small size at which RDF datasets become challenging for disk-backed systems.In-memory storage brings with it its own challenges. The relatively high cost of RAM necessitates a very compact representation, and the changing relationship between memory and CPU (particularly increasing RAM access latency) benefits designs that are aware of that relationship. This thesis presents an investigation into creating CPU-friendly data structures, along with a deep study of the common characteristics of popular RDF datasets. Together, these are used to inform the creation of a new data structure called the Adaptive Hierarchical RDF Index (AHRI), an in-memory, RDF-specific structure that outperforms traditional storage mechanisms in nearly every respect.AHRI is validated with a comprehensive evaluation against other commonly used inmemory data structures, along with a real world test against a memory-backed store, and a fast disk-based store allowed to cache its data in RAM. The results show that AHRI outperforms these systems with regards to both space consumption and read/write behaviour. The document subsequently describes future work that should provide substantial further improvements, making the use of RAM for RDF storage even more compellin
Peer feedback in an integrated, process-oriented ESL writing placement test
No full textA prevailing question across studies has been whether and to what extent ESL writers can help each other when working in dyads or groups. While most research focused on the effectiveness of peer feedback, relatively few studies took interest in what L2 students actually do during a peer review. Moreover, there has been a growing awareness of and interest in paired and group oral assessment, especially in examining interactional competence during paired speaking tests; however, to date not much has been explored with regards to the nature of peer interaction during a writing test. This study proposes to fill this gap in SLA and L2 testing research by examining the peer-review section of the English Placement Test (EPT), a process-oriented, integrated writing placement test offered to newly-admitted international students at the University of Illinois. The current study examined (a) test-takers’ perceptions and attitudes towards the peer-review section in a testing context, (b) the nature of peer interaction during the peer feedback process, and (c) its potential link to test-takers’ writing performance.
Test-takers generally showed positive attitudes and perceptions towards the peer review. They appreciated the opportunity to receive feedback from their peers and perceived the activity as helpful in writing their final essay. Test-takers also indicated that they focused more on rhetorical features than lexico-grammar features during the peer review.
Four patterns of interaction were identified during the peer review: collaborative, dominant/dominant, dominant/dominant monologue, and passive/passive. The collaborative pattern was the most common among the EPT examinees (n=19, 60%) in line with the findings of the previous research on patterns of interaction in classroom settings (e.g., Storch 2002; Zheng, 2012). A new pattern not observed in prior classroom studies, which I named dominant/dominant monologue, was observed among 29% of the pairs (n=9), whose interaction was monologic in nature with little or no engagement.
Written texts produced by the test-takers were then triangulated with the post-test questionnaire responses and peer interaction data to observe what changes were made as a result of peer interaction. Collaborative pairs made more detailed, specific comments that were revision-oriented, and many of these suggestions were reflected in the final drafts. In contrast, comments exchanged between non-collaborative pairs were more global in nature, and therefore, it was difficult to identify specific edits reflected in the final drafts. Regardless, most non-collaborative pairs appreciated the opportunity to receive feedback from their peers, and many reported making changes based on their peers’ feedback on their post-test questionnaire.
This study’s results stand to have valuable implications for both second language writing and language testing at large, and they provide insight to the nature and effect of peer interaction in an authentic, academic writing placement test setting. This study also emphasizes the role of peer review training and how this can be used to facilitate peer interaction and help test-takers achieve their best possible writing performance.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-05-01The student, Ha Ram Kim, accepted the attached license on 2019-04-12 at 14:10.The student, Ha Ram Kim, submitted this Dissertation for approval on 2019-04-12 at 14:10.This Dissertation was approved for publication on 2019-04-12 at 16:34.DSpace SAF Submission Ingestion Package generated from Vireo submission #13590 on 2019-08-22 at 16:21:10Made available in DSpace on 2019-08-23T20:44:44Z (GMT). No. of bitstreams: 2
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TBLT meets CMC: Using Virtual Worlds (VWs) in the language learning and teaching. An interview with Dr. Randall Sadler
No full textDr. Randall Sadler és professor al Departament de Lingüística de la Universitat d'Illinois a Urbana-Champaign (EUA). L'enfocament principal de la seva recerca és el paper de la Comunicació Mediada per l’Ordinador (CMO) i els Mons Virtuals (MV) en el procés d'ensenyament/aprenentatge de llengües. Mons virtuals són entorns en línia 3-D habitades per ‘persones’ amb la forma de avatars. Hi ha un gran nombre de mons virtuals, que van des entorns de joc molt reals - sovint referits com a Jocs en línia amb Multijugadors en Massiu (MMOG en anglès) - fins MVs que existeixen principalment com a entorns socials. Aquests inclouen Second Life, Active Worlds, Club Penguin, There, i molts més. L'enfocament principal del seu interès és a Second Life (SL), ja que hi ha una àmplia possibilitat d'aplicacions educatives a SL que estan en constant evolució.Dr. Randall Sadler is a Professor in the Department of Linguistics, University of Illinois at Urbana-Champaign (USA). The primary focus of Dr. Sadler’s current research is the role of Computer-Mediated Communication and Virtual Worlds (VWs) in the language learning/teaching process. Virtual Worlds are 3-D online environments inhabited by ‘people’ in the form of avatars. There are a large number of virtual worlds, ranging from true game
environments--often referred to as Massively-Multiplayer Online Games (MMOGs)--to VWs that exist primarily as social environments. These include Second Life, Active Worlds, Club Penguin, There, and many more. The primary focus of his interest is Second Life (SL) as there are a wide variety of education applications in SL that are constantly evolving.Dr. Randall Sadler es profesor en el Departamento de Lingüística de la Universidad de Illinois en Urbana-Champaign (EE.UU.). El enfoque principal de su investigación es el papel de la Comunicación Mediada por el Ordenador (CMO) y los Mundos Virtuales (MV) en el proceso de enseñanza/aprendizaje de lenguas. Mundos virtuales son entornos en línea 3-D habitadas por ‘personas’ en la forma de avatares. Hay un gran número de mundos virtuales, que van desde entornos de juego muy reales - a menudo referido como Juegos en línea con Multijugadores en Masivo (MMOG en inglés) - hasta MVs que existen principalmente como entornos sociales. Estos incluyen Second Life, Active Worlds, Club Penguin, There, y muchos más. El enfoque principal de su interés es en Second Life (SL), ya que hay una amplia variedad de aplicaciones educativas en SL que están en constante evolución
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