Gaming Fluencies: Pathways into Participatory Culture in a Community Design Studio

Many recent efforts to promote new literacies involve the promotion of creative media production as a way to foster youth’s literate engagement with digital media. Those interested in gaming literacies view game design as a way to engage youth in reflective and critical reading of the gaming culture. In this paper, we propose the concept of “gaming fluencies” to promote game design as a context in which youth not only learn to read but also to produce digital media in creative ways. Gaming fluencies also present the added benefit of addressing equity issues of participation in the new media literacy landscape. We report on an ethnographic study that documented urban youth producing digital games in a community technology center. Our analyses focus on an archive of 643 game designs collected over a 24-month period, selecting a random sample to identify evidence of creative and technical dimensions in game designs. In addition, we highlight three case studies of game designs to identify different pathways into the participatory culture. Our goal is to illustrate how gaming fluencies allow for a wide range of designs, provide low thresholds and high ceilings for complex projects, and make room for creative expression. In our discussion, we address how gaming fluencies represent a complementary pathway for learning and participation in today’s media culture

Locating Multiple Soft Faults in Wire Networks Using An Alternative DORT Implementation

International audienceDecomposition of the time reversal operator (DORT) was recently applied to the problem of detection and location of soft faults in wire networks and proved effectual when dealing with a single fault, even in the case of complex network configurations. In this paper, the case of location of multiple faults is addressed, first proving that the standard DORT formulation does not allow to take a clear decision about the individual position of each fault. An alternative version of the DORT, based on an updating procedure, is presented and demonstrated to enable accurate and selective location of multiple soft faults. The proposed procedure is also shown to allow estimating the reflection coefficient of each fault, thus giving access to their severity

Safeguarding Play in Virtual Worlds: Designs and Perspectives on Tween Player Participation in Community Management

Managing problematic interactions in online communities has been a challenge since the days of early text-based, multi-user environments. Research in this area has mostly focused on adults and older teens. In this article, we examine the interactions and commentaries of tween players in Whyville.net, a virtual world with (at the time of the study) more than 1.5 million registered players ages 8–16. To understand how tween players define problematic behavior and what they observe in their own community, we draw from an archive of online postings to Whyville’s newspaper. The postings cover the period from 2000 to 2009 and consist almost entirely of player-generated content. Complementing these tween writings are observations of an after school gaming club in which, over a period of three months, about 20 youth players ages 9–12 met almost daily to play for an hour on Whyville.net. We highlight one particular incident observed in the gaming club because it illustrates how club members dealt with problematic behavior experienced online. Finally, we address the challenges and opportunities that tween player participation in community management presents for managing online behavior and player safety

Imaging Techniques for soft fault detection and location in wiring networks

Les câbles électriques sont partout dans de nombreux domaines où le transfert d'énergie et de l'information est nécessaire pour garantir une bonne performance d'un système. Un jour ou l'autre, un câble dans un réseau va montrer des signes de faiblesse qui conduit à l'apparition de défauts soit francs ou non francs. Malgré le fait que plusieurs méthodes de diagnostic de fil électriques et non-électriques ont été étudiés et mis au point au cours des dernières décennies, les techniques basées réflectométrie ont fourni des résultats efficaces avec des défauts difficiles, mais ont montré moins fiables à chaque fois que des erreurs légères sont traitées.Basé sur un concept radicalement différent, la méthode DORT, développé à l'origine en acoustique a récemment été transposée à la propagation à ondes guidées, par exemple, les réseaux de fils, et montré pour détecter avec précision et localiser les défauts mous simples même dans les configurations de réseau complexes. D'autre part, plusieurs défauts ne peuvent être résolus séparément. Désormais une formulation alternative du DORT basée sur un système de mise à jour est proposée. Notamment, cette nouvelle approche, appelée EDORT, a permis de localiser plusieurs défauts non francs dans différents réseaux de câblage et a permis l'extraction de l'intensité de chaque défaut uniquement. D'autre part, ces méthodes dans le domaine temporel comptent sur la disponibilité de potentiellement importantes largeurs de bande, afin de créer les conditions pour la résolution spatiale. Retournement temporel (TR) classement de signaux multiples, également connu sous le TR-MUSIC, assurée sous-longueur d'onde résolution spatiale des emplacements des défauts tout en travaillant sur une base mono-fréquence. TR-MUSIC a montré une bonne performance dans la localisation unique, ainsi que de multiples défauts non francs dans différentes configurations de réseau. Il a également montré pour permettre la récupération du coefficient de réflexion de chaque défaut séparément.Electrical cables are everywhere in many fields where the transfer of energy and information is necessary to guarantee a good performance of a system. One day or another, a cable in a network will show signs of weakness leading to the appearance of either hard or soft faults. Despite the fact that several electric and non-electric wire diagnosis methods have been studied and developed throughout the last few decades, reflectometrybased techniques have been providing effective results with hard faults, but have shown to be less reliable whenever soft faults are addressed. Based on a radically different concept, the DORT method, originally developed in acoustics was recently transposed to guided-wave propagation, e.g., wire networks, and shown to precisely detect and locate single soft faults even within complex network configurations. On the other hand, multiple faults cannot be resolved separately. Henceforth an alternative formulation of the DORT based on an updating scheme is proposed. Notably, this novel approach, referred to as EDORT, allowed locating multiple soft faults in different wiring networks and enabled extracting the intensity of each fault solely. On the other hand, such time domain methods rely on the availability of potentially large bandwidths, in order to create the conditions for spatial resolution. Time-reversal (TR) multiple signal classification, also known as TR-MUSIC, ensured sub-wavelength spatial resolution of the faults’ locations while working on a single-frequency basis. TR-MUSIC has shown a good performance in locating single as well as multiple soft faults in different network configurations. It has also shown to allow retrieving the reflection coefficient of each fault separately

Techniques d'imagerie pour la détection et la localisation de défauts non francs dans les réseaux de câblage

Electrical cables are everywhere in many fields where the transfer of energy and information is necessary to guarantee a good performance of a system. One day or another, a cable in a network will show signs of weakness leading to the appearance of either hard or soft faults. Despite the fact that several electric and non-electric wire diagnosis methods have been studied and developed throughout the last few decades, reflectometrybased techniques have been providing effective results with hard faults, but have shown to be less reliable whenever soft faults are addressed. Based on a radically different concept, the DORT method, originally developed in acoustics was recently transposed to guided-wave propagation, e.g., wire networks, and shown to precisely detect and locate single soft faults even within complex network configurations. On the other hand, multiple faults cannot be resolved separately. Henceforth an alternative formulation of the DORT based on an updating scheme is proposed. Notably, this novel approach, referred to as EDORT, allowed locating multiple soft faults in different wiring networks and enabled extracting the intensity of each fault solely. On the other hand, such time domain methods rely on the availability of potentially large bandwidths, in order to create the conditions for spatial resolution. Time-reversal (TR) multiple signal classification, also known as TR-MUSIC, ensured sub-wavelength spatial resolution of the faults’ locations while working on a single-frequency basis. TR-MUSIC has shown a good performance in locating single as well as multiple soft faults in different network configurations. It has also shown to allow retrieving the reflection coefficient of each fault separately.Les câbles électriques sont partout dans de nombreux domaines où le transfert d'énergie et de l'information est nécessaire pour garantir une bonne performance d'un système. Un jour ou l'autre, un câble dans un réseau va montrer des signes de faiblesse qui conduit à l'apparition de défauts soit francs ou non francs. Malgré le fait que plusieurs méthodes de diagnostic de fil électriques et non-électriques ont été étudiés et mis au point au cours des dernières décennies, les techniques basées réflectométrie ont fourni des résultats efficaces avec des défauts difficiles, mais ont montré moins fiables à chaque fois que des erreurs légères sont traitées.Basé sur un concept radicalement différent, la méthode DORT, développé à l'origine en acoustique a récemment été transposée à la propagation à ondes guidées, par exemple, les réseaux de fils, et montré pour détecter avec précision et localiser les défauts mous simples même dans les configurations de réseau complexes. D'autre part, plusieurs défauts ne peuvent être résolus séparément. Désormais une formulation alternative du DORT basée sur un système de mise à jour est proposée. Notamment, cette nouvelle approche, appelée EDORT, a permis de localiser plusieurs défauts non francs dans différents réseaux de câblage et a permis l'extraction de l'intensité de chaque défaut uniquement. D'autre part, ces méthodes dans le domaine temporel comptent sur la disponibilité de potentiellement importantes largeurs de bande, afin de créer les conditions pour la résolution spatiale. Retournement temporel (TR) classement de signaux multiples, également connu sous le TR-MUSIC, assurée sous-longueur d'onde résolution spatiale des emplacements des défauts tout en travaillant sur une base mono-fréquence. TR-MUSIC a montré une bonne performance dans la localisation unique, ainsi que de multiples défauts non francs dans différentes configurations de réseau. Il a également montré pour permettre la récupération du coefficient de réflexion de chaque défaut séparément

Synthesis of Cyclic α,β-unsaturated Ketones via a Divergent Aldehyde Allylation and Ring-closing Metathesis Method

Montmorillonite-catalyzed allylation of aldehydes with potassium allyltrifluoroborate is a convenient method for the synthesis of homoallylic alcohols. This chemistry was applied to various unsaturated aldehydes, and the homoallylic alcohols produced were used as common intermediates for two separate but related synthetic routes to α,β-unsaturated ketones. In the first route, oxidation of the alcohol to the ketone was followed by base-catalyzed isomerization of the olefin to the α,β-unsaturated ketone. This was subjected to ring closing metathesis conditions to afford the cyclic enone of ring size n. In the other route, ring-closing metathesis was performed first, followed by oxidation of the alcohol and isomerization of the olefin to the cyclic enone of ring size n+1.MAS

On the Diagnosis of Incipient Faults in Transmission Lines Using a Projection Approach Based on Phase Patterns

International audienceThroughout the last decade, the problem of soft fault detection in transmission lines have been overflown with contemporary powerful technologies. However, a vast majority of state-of-the-art techniques including the well-known reflectometry methods, require bandwidths in the order of hundreds of megahertz for providing spatial resolution in the millimeter range of faults' locations. On the other hand, an emerging technique based on the analysis of multi-port transmission and reflection parameters, often referred to as the Time-reversal multiple signal classification (TR-MUSIC) ensured location accuracy and sub-millimeter resolution of multiple soft faults in complex wire networks. More importantly, this was made possible using continuous wave excitations even at low frequencies. However, as any other existing method, it suffered from the problem of attenuation inherent to transmission lines. In this paper, we will introduce a method based on Green function phase pattern analysis of tested cables relying only on reflection parameters, with no need for acquiring the transmission ones. In effect, testing long cables as in the case of power grids becomes possible. The proposed technique is shown to be robust against attenuation. Besides, it appears to be readily adapted for lively monitoring transmission lines, thanks to its continuous wave excitation abilities. The technique is shown to operate frequency by frequency, which allows the choice of specified frequency samples if distortion is present. Moreover, the proposed processing is shown to reinstate precise super-resolved estimates of soft fault locations. Experimental results based on coaxial cable implementation is provided to validate the method's feasibility

Shielding Damage Characterization in Twisted Pair Cables Using OMTDR-based Reflectometry and Inverse Problems

International audienceAeronautical wiring and interconnect systems are highly exposed to severe conditions leading to serious security problems. In such systems, the predictive diagnosis of incipient faults becomes an economic and human requirement in the perspective of predictive maintenance. This paper proposes to study and develop methods and models to detect incipient faults and characterize them in wiring and interconnect systems. A model-based inversion process combined with optimization-based algorithms have formed a suitable, reliable and efficient technique for incipient fault characterization when processed with reflectometry. To do so, a shielded twisted pair cable with a shielding damage has been modeled using Finite element method and simulated using reflectometry. It consists in injecting a wideband test signal down to the cable and recording the reflected echoes at each impedance discontinuity. The analysis of the reflectometry-based measurements permits to detect and locate incipient fault. A Genetic Algorithm (GA) is then performed to estimate the fault's features such as length, width or per-unit-length parameters (RLCG), etc., which becomes equally interesting for predictive maintenance. The proposed methodology is validated by experimental results using an electronic card including Xilinx Zunq 7010 FPGA to inject/receive Orthogonal Multi-Tone Time Domain Reflectometry (OMTDR)

Multi-Frequency TR-MUSIC Processing to Locate Soft Faults in Cables Subject to Noise

International audienceTime-Reversal multiple signal classification (TR-MUSIC) has recently been shown to be an effective technique to locate multiple soft faults in wire networks, thanks to its sub-millimeter location accuracy. TR-MUSIC processes transmission and reflection data measured at a single frequency into a function of space, the pseudo spectrum, expected to present singularities only at a fault position. At frequencies high enough, the spatial periodicity that comes with the propagation of harmonic signals leads to multiples such singularities, of which only one represents the fault position, while the remaining are ghosts faults. TR-MUSIC was therefore introduced using a single continuous-wave excitation at frequencies low enough to avoid ghosts, an approach suitable only to noiseless configurations. This paper explores the effects of noise on TR-MUSIC fault location by first highlighting its high sensitivity to noise at low frequency. A potentially lower sensitivity is shown to exist at high frequencies, where ghosts positions are found. A multi-frequency processing is introduced, allowing at the same time to solve the ambiguity in the fault position and to effectively control the impact of noise on its location accuracy. The proposed processing is shown to reinstate precise super-resolved estimates of fault locations even for signal-to-noise ratios as low as 5 dB, without requiring to the use of wide-band signals. Index Terms-Fault detection, fault location, soft faults, complex wire networks, additive noise