Teaching by chat

This paper discusses some didactical aspects of chat usage for instructional purposes. Areas covered range from the choice of course type and student group for using chats, to the preparation and moderation of chats, and discussing how to manage both troublemaking students and systems. In February 1998 I was the chair of a committee at my previous university that was authoring a recommendation list about the Internet to the president of the school. One of our recommendations was to eliminate the IRC server (Internet Relay Chat), since it was only causing traffic and was just being used for games. We stated that we could not envision a use for chatting either for research or for instructional purposes. Five years later here I am: teaching 4 of my 5 courses by way of chat. There has been an enormous growth in the use of chat-based instruction, but also quite a lot of problems encountered. Much of the available literature addresses technical problems, or discusses chats from an educational psychology perspective. This paper will address ten of the didactical issues in chat-based instruction, summarizing the experiences that I have made in many years of chat experience (DIPF/Orig.)

On-light: optical social network

Social networks are a recent phenomenon of communication, with a high prevalence of young users. This concept serves as a motto for a multidisciplinary project, which aims to create a simple communication network, using light as the transmission medium. Mixed team, composed by students from secondary and higher education schools, are partners on the development of an optical transceiver. A LED lamp array and a small photodiode are the optical transmitter and receiver, respectively. Using several transceivers aligned with each other, this con guration creates a ring communication network, enabling the exchange of messages between users. Through this project, some concepts addressed in physics classes from secondary schools (e.g. photoelectric phenomena and the properties of light) are experimentally veri ed and used to communicate, in a classroom or a laboratory.

Electracy in Praxis: Pedagogical Relays for an Undergraduate Writing Curriculum

The paradigm shift from traditional print literacy to the postmodern fragmentation, nonlinearity, and multimodality of writing for the Internet is realized in Gregory L. Ulmer’s electracy theory. Ulmer’s open invitation to continually invent the theory has resulted in the proliferation of relays, or weak models, by electracy advocates for understanding and applying the theory. Most relays, however, remain theoretical rather than practical for the writing classroom, and electracy instruction remains rare, potentially hindering the theory’s development. In this dissertation, I address the gap in electracy praxis by adapting, developing, and remixing relays for a functional electracy curriculum with first-year writing students in the Virginia Community College System as the target audience. I review existing electracy relays, pedagogical applications, and assessment practices – Ulmer’s and those of electracy advocates – before introducing my own relays, which take the form of modules. My proposed relay modules are designed for adaptability with the goals of introducing digital natives to the logic of new media and guiding instructors to possible implementations of electracy. Each module contains a justification, core competencies and learning outcomes, optional readings, an assignment with supplemental exercises, and assessment criteria. My Playlist, Transduction, and (Sim)ulation relays follow sound backward curricular design principles and emphasize core hallmarks of electracy as juxtaposed alongside literacy. This dissertation encourages the instruction of new media in Ulmer’s postmodern apparatus in which student invention via the articulation of fragments from various semiotic modes stems from and results in new methodologies for and understandings of digital communication.

Energy Cooperation in Energy Harvesting Communication Systems

In energy harvesting communications, users transmit messages using energy harvested from nature. In such systems, transmission policies of the users need to be carefully designed according to the energy arrival profiles. When the energy management policies are optimized, the resulting performance of the system depends only on the energy arrival profiles. In this dissertation, we introduce and analyze the notion of energy cooperation in energy harvesting communications where users can share a portion of their harvested energy with the other users via wireless energy transfer. This energy cooperation enables us to control and optimize the energy arrivals at users to the extent possible. In the classical setting of cooperation, users help each other in the transmission of their data by exploiting the broadcast nature of wireless communications and the resulting overheard information. In contrast to the usual notion of cooperation, which is at the signal level, energy cooperation we introduce here is at the battery energy level. In a multi-user setting, energy may be abundant in one user in which case the loss incurred by transferring it to another user may be less than the gain it yields for the other user. It is this cooperation that we explore in this dissertation for several multi-user scenarios, where energy can be transferred from one user to another through a separate wireless energy transfer unit. We first consider the offline optimal energy management problem for several basic multi-user network structures with energy harvesting transmitters and one-way wireless energy transfer. In energy harvesting transmitters, energy arrivals in time impose energy causality constraints on the transmission policies of the users. In the presence of wireless energy transfer, energy causality constraints take a new form: energy can flow in time from the past to the future for each user, and from one user to the other at each time. This requires a careful joint management of energy flow in two separate dimensions, and different management policies are required depending on how users share the common wireless medium and interact over it. In this context, we analyze several basic multi-user energy harvesting network structures with wireless energy transfer. To capture the main trade-offs and insights that arise due to wireless energy transfer, we focus our attention on simple two- and three-user communication systems, such as the relay channel, multiple access channel and the two-way channel. Next, we focus on the delay minimization problem for networks. We consider a general network topology of energy harvesting and energy cooperating nodes. Each node harvests energy from nature and all nodes may share a portion of their harvested energies with neighboring nodes through energy cooperation. We consider the joint data routing and capacity assignment problem for this setting under fixed data and energy routing topologies. We determine the joint routing of energy and data in a general multi-user scenario with data and energy transfer. Next, we consider the cooperative energy harvesting diamond channel, where the source and two relays harvest energy from nature and the physical layer is modeled as a concatenation of a broadcast and a multiple access channel. Since the broadcast channel is degraded, one of the relays has the message of the other relay. Therefore, the multiple access channel is an extended multiple access channel with common data. We determine the optimum power and rate allocation policies of the users in order to maximize the end-to-end throughput of this system. Finally, we consider the two-user cooperative multiple access channel with energy harvesting users. The users cooperate at the physical layer (data cooperation) by establishing common messages through overheard signals and then cooperatively sending them. For this channel model, we investigate the effect of intermittent data arrivals to the users. We find the optimal offline transmit power and rate allocation policy that maximize the departure region. When the users can further cooperate at the battery level (energy cooperation), we find the jointly optimal offline transmit power and rate allocation policy together with the energy transfer policy that maximize the departure region.

Cybersex in portuguese chatrooms: A study of sexual behaviors related to online sex

The present article is about a particular form of sexual activity on the Internet: cybersex in chatrooms-in Portuguese by Portuguese people. This study aims to identify the reasons for engaging in cybersex on chats and the behavioral domains that characterize this activity. To carry out the study, we developed a self-report questionnaire that we made available on a website. The sample was collected online (n = 400) through the Portuguese Internet Relay Chat. Factor analyses revealed seven domain structures: (a) social skills, (b) preference for cybersex, (c) filter for a later date, (d) sex by phone, (e) fantasies, (f) using masks, and (g) impact on real relationships. We found a huge variety of sexual attitudes and behaviors connected to cybersex in chatrooms and the existence of two major trends: (a) people that use these chats as a starting place for offline relationships (online anonymity prevents the fear of rejection and social sanctions in real life), and (b) people who want and prefer online sex without any interest in further real contacts.

JOINT ENERGY BEAMFORMING AND TIME ASSIGNMENT FOR COOPERATIVE WIRELESS POWERED NETWORKS

Wireless power transfer (WPT) and radio frequency (RF)-based energy har- vesting arouses a new wireless network paradigm termed as wireless powered com- munication network (WPCN), where some energy-constrained nodes are enabled to harvest energy from the RF signals transferred by other energy-sufficient nodes to support the communication operations in the network, which brings a promising approach for future energy-constrained wireless network design. In this paper, we focus on the optimal WPCN design. We consider a net- work composed of two communication groups, where the first group has sufficient power supply but no available bandwidth, and the second group has licensed band- width but very limited power to perform required information transmission. For such a system, we introduce the power and bandwidth cooperation between the two groups so that both group can accomplish their expected information delivering tasks. Multiple antennas are employed at the hybrid access point (H-AP) to en- hance both energy and information transfer efficiency and the cooperative relaying is employed to help the power-limited group to enhance its information transmission throughput. Compared with existing works, cooperative relaying, time assignment, power allocation, and energy beamforming are jointly designed in a single system. Firstly, we propose a cooperative transmission protocol for the considered system, where group 1 transmits some power to group 2 to help group 2 with information transmission and then group 2 gives some bandwidth to group 1 in return. Sec- ondly, to explore the information transmission performance limit of the system, we formulate two optimization problems to maximize the system weighted sum rate by jointly optimizing the time assignment, power allocation, and energy beamforming under two different power constraints, i.e., the fixed power constraint and the aver- age power constraint, respectively. In order to make the cooperation between the two groups meaningful and guarantee the quality of service (QoS) requirements of both groups, the minimal required data rates of the two groups are considered as constraints for the optimal system design. As both problems are non-convex and have no known solutions, we solve it by using proper variable substitutions and the semi-definite relaxation (SDR). We theoretically prove that our proposed solution method can guarantee to find the global optimal solution. Thirdly, consider that the WPCN has promising application potentials in future energy-constrained net- works, e.g., wireless sensor network (WSN), wireless body area network (WBAN) and Internet of Things (IoT), where the power consumption is very critical. We investigate the minimal power consumption optimal design for the considered co- operation WPCN. For this, we formulate an optimization problem to minimize the total consumed power by jointly optimizing the time assignment, power allocation, and energy beamforming under required data rate constraints. As the problem is also non-convex and has no known solutions, we solve it by using some variable substitutions and the SDR method. We also theoretically prove that our proposed solution method for the minimal power consumption design guarantees the global optimal solution. Extensive experimental results are provided to discuss the system performance behaviors, which provide some useful insights for future WPCN design. It shows that the average power constrained system achieves higher weighted sum rate than the fixed power constrained system. Besides, it also shows that in such a WPCN, relay should be placed closer to the multi-antenna H-AP to achieve higher weighted sum rate and consume lower total power.

Endoscopic optical coherence tomography : design and application

This thesis presents an investigation on endoscopic optical coherence tomography (OCT). As a noninvasive imaging modality, OCT emerges as an increasingly important diagnostic tool for many clinical applications. Despite of many of its merits, such as high resolution and depth resolvability, a major limitation is the relatively shallow penetration depth in tissue (about 2∼3 mm). This is mainly due to tissue scattering and absorption. To overcome this limitation, people have been developing many different endoscopic OCT systems. By utilizing a minimally invasive endoscope, the OCT probing beam can be brought to the close vicinity of the tissue of interest and bypass the scattering of intervening tissues so that it can collect the reflected light signal from desired depth and provide a clear image representing the physiological structure of the region, which can not be disclosed by traditional OCT. In this thesis, three endoscope designs have been studied. While they rely on vastly different principles, they all converge to solve this long-standing problem.

A hand-held endoscope with manual scanning is first explored. When a user is holding a hand- held endoscope to examine samples, the movement of the device provides a natural scanning. We proposed and implemented an optical tracking system to estimate and record the trajectory of the device. By registering the OCT axial scan with the spatial information obtained from the tracking system, one can use this system to simply ‘paint’ a desired volume and get any arbitrary scanning pattern by manually waving the endoscope over the region of interest. The accuracy of the tracking system was measured to be about 10 microns, which is comparable to the lateral resolution of most OCT system. Targeted phantom sample and biological samples were manually scanned and the reconstructed images verified the method.

Next, we investigated a mechanical way to steer the beam in an OCT endoscope, which is termed as Paired-angle-rotation scanning (PARS). This concept was proposed by my colleague and we further developed this technology by enhancing the longevity of the device, reducing the diameter of the probe, and shrinking down the form factor of the hand-piece. Several families of probes have been designed and fabricated with various optical performances. They have been applied to different applications, including the collector channel examination for glaucoma stent implantation, and vitreous remnant detection during live animal vitrectomy.

Lastly a novel non-moving scanning method has been devised. This approach is based on the EO effect of a KTN crystal. With Ohmic contact of the electrodes, the KTN crystal can exhibit a special mode of EO effect, termed as space-charge-controlled electro-optic effect, where the carrier electron will be injected into the material via the Ohmic contact. By applying a high voltage across the material, a linear phase profile can be built under this mode, which in turn deflects the light beam passing through. We constructed a relay telescope to adapt the KTN deflector into a bench top OCT scanning system. One of major technical challenges for this system is the strong chromatic dispersion of KTN crystal within the wavelength band of OCT system. We investigated its impact on the acquired OCT images and proposed a new approach to estimate and compensate the actual dispersion. Comparing with traditional methods, the new method is more computational efficient and accurate. Some biological samples were scanned by this KTN based system. The acquired images justified the feasibility of the usage of this system into a endoscopy setting. My research above all aims to provide solutions to implement an OCT endoscope. As technology evolves from manual, to mechanical, and to electrical approaches, different solutions are presented. Since all have their own advantages and disadvantages, one has to determine the actual requirements and select the best fit for a specific application.

O design de produto como suporte a campanhas publicitárias

Dissertação de Mestrado para obtenção do grau de Mestre em Design de Produto, apresentada na Universidade de Lisboa - Faculdade de Arquitectura.

Application-Based Analysis of Register File Criticality for Reliability Assessment in Embedded Microprocessors

There is an increasing concern to reduce the cost and overheads during the development of reliable systems. Selective protection of most critical parts of the systems represents a viable solution to obtain a high level of reliability at a fraction of the cost. In particular to design a selective fault mitigation strategy for processor-based systems, it is mandatory to identify and prioritize the most vulnerable registers in the register file as best candidates to be protected (hardened). This paper presents an application-based metric to estimate the criticality of each register from the microprocessor register file in microprocessor-based systems. The proposed metric relies on the combination of three different criteria based on common features of executed applications. The applicability and accuracy of our proposal have been evaluated in a set of applications running in different microprocessors. Results show a significant improvement in accuracy compared to previous approaches and regardless of the underlying architecture.

El relevo de género en la elaboración alfarera. El caso de las comunidades Guaitil y San Vicente, provincia de Guanacaste, Costa Rica

Resumen El artículo presenta un breve recorrido por la historia reciente de las comunidades alfareras costarricenses de Guaitil y San Vicente, en la región Chorotega. Profundiza en el cambio intergeneracional y el relevo de género que comprometen el mantenimiento de esta tradición ancestral. Asimismo introduce la importancia que tienen los sellos de calidad diferenciada por territorio, como las denominaciones de origen (DO): una herramienta de rescate, valoración y protección de estos saberes culturales. El aporte al conocimiento de la actividad alfarera en Guaitil y San Vicente presenta datos de un censo realizado por el centro especializado CadenAgro de la Universidad Nacional de Costa Rica (UNA) en los talleres artesanos. La información obtenida muestra un panorama para la gestión a largo plazo de la DO que garantice el mantenimiento de las prácticas culturales de las comunidades artesanas. Abstract The article presents a brief overview of the recent history of potter Costa Rican communities Guaitil and San Vicente, in the Chorotega region. It deepen is intergenerational change and gender relay involving the maintenance of this ancient tradition. It also introduces the importance of quality labels differentiated by territory, as designations of origin (DO): a rescue tool, valuation and protection of this cultural knowledge. The contribution to knowledge of the activity of pottery in San Vicente and Guaitil presents data from a census conducted by the specialized center CadenAgro of the National University of Costa Rica (UNA) in artisan workshops. The information obtained shows an overview for long-term management of DO to ensure the maintenance of the cultural practices of artisan communities.

Lieu de liens, lieu de vie : oser le réseau comme alternative à la vulnérabilité : le cas des demandeurs d’asile à Projet Refuge (Montréal).

La vulnérabilité est l’attribut fondamental justifiant le passage des frontières du refuge canadien (Rousseau et al., 2002 ; Clément et Bolduc, 2004). Elle est preuve d’insécurité pour la victime requérant l’asile ; elle est aussi porteuse d’espérance de sécurité en terre hospitalière. Elle est pourtant potentiel réactualisé dans l’insécurité d’un statut incertain en terre d’accueil (Agamben, 1997 ; D’Halluin, 2004). Violente immersion. En attendant que les preuves de sa vulnérabilité originelle soient validées, le demandeur d’asile se retrouve dans un entre-deux a-territorial et atemporel (Agier, 2002 ; Le Blanc, 2010) et dans une précarité tout aussi dangereuse (Ouimet et al., 2009). Des besoins émergent en cette terre inconnue, or l’accès aux soins de santé lui est limité par des textes de lois ambigus et leurs interprétations maladroites (Harris et Zuberi, 2015). Ainsi lorsqu’il se heurte à des barrières érigées par une transmission d’informations défectueuse, sa précarité ne fait qu’empirer. Tel un boomerang, ce paradoxe cultive leur vulnérabilité. Alors que les recherches interrogent les divers intervenants en santé (Asgary et Smith, 2013), j’ai choisi de donner la parole aux premiers concernés et de relayer leur vécu par rapport à leur propre personne. Deux objectifs principaux guident la recherche : documenter dans un premier temps leur parcours de quête de soins à partir de la circulation des informations formelles et informelles dans le but de sonder leur avis sur la vulnérabilité qui leur est attribuée ; documenter dans un second temps leur parcours migratoire de quête de soi afin de mettre en lumière les stratégies alternatives d’entrée en contact avec la société d’accueil pour négocier voire rejeter cette identité vulnérable. J’ai rencontré pour cela des demandeurs d’asile lors d’un terrain de huit mois au sein d’un organisme communautaire d’hébergement à Montréal. Dans ce contexte d’accompagnement et de stabilité spatiale, accalmie bienvenue au terme d’un itinéraire semé d’embûches, les ressources informationnelles sont à leur disposition et la reconnaissance sociale est à l’honneur. En parallèle, beaucoup témoignent de la diminution de leurs besoins de soins de santé. En cette communauté thérapeutique (Pocreau, 2005), véritable tremplin vers la société d’accueil en attendant un statut reconnu, ils bénéficient d’une possibilité de participation sociale et d’un sentiment d’appartenance valorisant. Si des conditions précaires peuvent aggraver la vulnérabilité, le bricolage de conditions positives favorise la résilience (Cleveland et al., 2014), créant un environnement revitalisant qui leur permet de rebondir.

Lieu de liens, lieu de vie : oser le réseau comme alternative à la vulnérabilité : le cas des demandeurs d’asile à Projet Refuge (Montréal)

La vulnérabilité est l’attribut fondamental justifiant le passage des frontières du refuge canadien (Rousseau et al., 2002 ; Clément et Bolduc, 2004). Elle est preuve d’insécurité pour la victime requérant l’asile ; elle est aussi porteuse d’espérance de sécurité en terre hospitalière. Elle est pourtant potentiel réactualisé dans l’insécurité d’un statut incertain en terre d’accueil (Agamben, 1997 ; D’Halluin, 2004). Violente immersion. En attendant que les preuves de sa vulnérabilité originelle soient validées, le demandeur d’asile se retrouve dans un entre-deux a-territorial et atemporel (Agier, 2002 ; Le Blanc, 2010) et dans une précarité tout aussi dangereuse (Ouimet et al., 2009). Des besoins émergent en cette terre inconnue, or l’accès aux soins de santé lui est limité par des textes de lois ambigus et leurs interprétations maladroites (Harris et Zuberi, 2015). Ainsi lorsqu’il se heurte à des barrières érigées par une transmission d’informations défectueuse, sa précarité ne fait qu’empirer. Tel un boomerang, ce paradoxe cultive leur vulnérabilité. Alors que les recherches interrogent les divers intervenants en santé (Asgary et Smith, 2013), j’ai choisi de donner la parole aux premiers concernés et de relayer leur vécu par rapport à leur propre personne. Deux objectifs principaux guident la recherche : documenter dans un premier temps leur parcours de quête de soins à partir de la circulation des informations formelles et informelles dans le but de sonder leur avis sur la vulnérabilité qui leur est attribuée ; documenter dans un second temps leur parcours migratoire de quête de soi afin de mettre en lumière les stratégies alternatives d’entrée en contact avec la société d’accueil pour négocier voire rejeter cette identité vulnérable. J’ai rencontré pour cela des demandeurs d’asile lors d’un terrain de huit mois au sein d’un organisme communautaire d’hébergement à Montréal. Dans ce contexte d’accompagnement et de stabilité spatiale, accalmie bienvenue au terme d’un itinéraire semé d’embûches, les ressources informationnelles sont à leur disposition et la reconnaissance sociale est à l’honneur. En parallèle, beaucoup témoignent de la diminution de leurs besoins de soins de santé. En cette communauté thérapeutique (Pocreau, 2005), véritable tremplin vers la société d’accueil en attendant un statut reconnu, ils bénéficient d’une possibilité de participation sociale et d’un sentiment d’appartenance valorisant. Si des conditions précaires peuvent aggraver la vulnérabilité, le bricolage de conditions positives favorise la résilience (Cleveland et al., 2014), créant un environnement revitalisant qui leur permet de rebondir.

Development of metabotropic glutamate receptors from trigeminal nuclei to barrel cortex in postnatal mouse

Expression patterns of group I (mGluR1α and mGluR5)and group II (mGluR2/3) metabotropic glutamate receptor subtypes were examined immunocytochemically in the trigeminal system of mice during the first 3 weeks of postnatal development, when somatotopic whisker representations are sequentially established from brainstem through thalamus to cerebral cortex. Immunostaining for all three epitopes formed whisker-related patterns in the trigeminal nuclei from postnatal day (P) 0, in the ventral posterior thalamic nucleus from P2, and in the posteromedial barrel subfield of somatosensory cortex (SI) from P4. The appearance of whisker-related patterns was preceded by increased levels of immunostaining of the neuropil, which subsequently declined from the trigeminal nuclei upward. In SI, mGluR1α-positive neurons were observed in all cortical layers from P2. mGluR5 was localized in neurons, glial cells, and neuropil from P2. mGluR2/3 immunostaining was distributed only in the neuropil at all ages. The three receptor subtypes showed moderate to high expression in deep layer V throughout development. Transient expression peaked in the hollows of layer IV barrels from P4 to P9, and then fell off as expression increased in supragranular layers from P14 to P21. The deep aspect of the cortical subplate (layer VIb) showed dense mGluR5 and less dense mGluR1α immunostaining throughout development. Up-regulation of expression of group I and II mGluRs is correlated with the growth and refinement of connectivity and the establishment of somatotopic patterns in the three main relay stations of the trigeminal system. This finding suggests roles for mGluRs in the early processing of sensory information and in developmental plasticity.

Synthetic data generation for the assessment of antimicrobial resistance through machine learning

As a consequence of the diffusion of next generation sequencing techniques, metagenomics databases have become one of the most promising repositories of information about features and behavior of microorganisms. One of the subjects that can be studied from those data are bacteria populations. Next generation sequencing techniques allow to study the bacteria population within an environment by sampling genetic material directly from it, without the needing of culturing a similar population in vitro and observing its behavior. As a drawback, it is quite complex to extract information from those data and usually there is more than one way to do that; AMR is no exception. In this study we will discuss how the quantified AMR, which regards the genotype of the bacteria, can be related to the bacteria phenotype and its actual level of resistance against the specific substance. In order to have a quantitative information about bacteria genotype, we will evaluate the resistome from the read libraries, aligning them against CARD database. With those data, we will test various machine learning algorithms for predicting the bacteria phenotype. The samples that we exploit should resemble those that could be obtained from a natural context, but are actually produced by a read libraries simulation tool. In this way we are able to design the populations with bacteria of known genotype, so that we can relay on a secure ground truth for training and testing our algorithms.

Instrument transformers with Digital outputting high voltage power networks

In recent years, energy modernization has focused on smart engineering advancements. This entails designing complicated software and hardware for variable-voltage digital substations. A digital substation consists of electrical and auxiliary devices, control and monitoring devices, computers, and control software. Intelligent measurement systems use digital instrument transformers and IEC 61850-compliant information exchange protocols in digital substations. Digital instrument transformers used for real-time high-voltage measurements should combine advanced digital, measuring, information, and communication technologies. Digital instrument transformers should be cheap, small, light, and fire- and explosion-safe. These smaller and lighter transformers allow long-distance transmission of an optical signal that gauges direct or alternating current. Cost-prohibitive optical converters are a problem. To improve the tool's accuracy, amorphous alloys are used in the magnetic circuits and compensating feedback. Large-scale voltage converters can be made cheaper by using resistive, capacitive, or hybrid voltage dividers. In known electronic voltage transformers, the voltage divider output is generally on the low-voltage side, facilitating power supply organization. Combining current and voltage transformers reduces equipment size, installation, and maintenance costs. These two gadgets cost less together than individually. To increase commercial power metering accuracy, current and voltage converters should be included into digital instrument transformers so that simultaneous analogue-to-digital samples are obtained. Multichannel ADC microcircuits with synchronous conversion start allow natural parallel sample drawing. Digital instrument transformers are created adaptable to substation operating circumstances and environmental variables, especially ambient temperature. An embedded microprocessor auto-diagnoses and auto-calibrates the proposed digital instrument transformer.