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A detailed analysis is presented of the gravitational microlensing by intervening compact objects of the black hole shadows imaged by the Event Horizon Telescope (EHT). We show how the center, size, and shape of the shadow depend on the Einstein angle relative to the true/unlensed shadow size, and how the location of the lens affects the shift, size, and asymmetry of the black hole shadow due to microlensing. Assuming a supermassive black hole (SMBH) casts a circular-shaped true shadow, microlensing can create an asymmetry of up to approximately 8\%, which is twice the asymmetry caused by the SMBH's spin and its tilt relative to us. Furthermore, the size can be enhanced by $\sim$50\% of the true shadow. Currently, the terrestrial baselines of EHT lack the resolution to detect microlensing signatures in the shadows. However, future expansions of EHT including space-based baselines at the Moon and L$_2$, could potentially enable the detection of microlensing events. For Sgr~A$^*$, an event rate of 0.0014 per year makes the microlensing phenomena difficult to observe even with space-based baselines for the stellar population in the stellar bulge and stellar disk for lens mass $\sim M_\odot$. However, continuously monitoring the shadow of Sgr~A$^*$ could offer novel insights into the compact object population surrounding the galactic center., Comment: 15 pages, 13 figures

With enormous amount of linguistic data present on web, text analysis has become one of the major fields of interest today. This field includes sentiment analysis, information retrieval, text document classification, knowledge based modeling, content similarity measure, data clustering, words prediction/correction, decision making etc. Managing and processing such data has vital importance. The field being quite broad, our focus is mainly on transportation related social media(Twitter) data extraction, text categorization/classification which can be further sub-divided into concept discovery, word sense disambiguation and sentiment analysis to analyze performance of existing transportation system worldwide. Concept discovery is the method of extracting the actual concept/context in which the text is about. This also allows us to filter irrelevant data. Word sense disambiguation is to find the correct sense in which a word is being used in a sentence. It is the basic necessity for concept discovery. A lot of research has been done in this field with major improvements. However, when it comes to short texts, the field still seems in nascent stage. Moreover, most of the methods today require huge amount training corpus(database). Arranging such corpus is a cumbersome task and requires a lot of human effort. The other problem with the existing methods are that they require a set of defined concepts from which a concept is chosen and labeled to text. We will consider the case of finding a general context. In this work a novel approach has been proposed for word sense disambiguation which in turn allows us to find general context. For this purpose, I have used the existing knowledge based semantic dictionary called WordNet. This methodology helps in avoiding the use of huge corpus and works for general context recognition. Our focus is on short-texts(Tweets) but the concept is easily applicable to text documents as well. Sentiment measuring technique was applied on extracted data and the scores were mapped to Google maps based on the location information present in the tweets. This clearly points out the locations where people are more frustrated with the existing transportation system and need immediate attention for improvements.

The aim of the study was to evaluate the benefit of vacuum‐assisted closure (VAC) therapy in the management of deep, alloplastic graft infections (Szilagyi grade III) in the groin. From 2000 to 2009, we identified and included in our study 72 deep inguinal infections in 68 patients, involving native as well as synthetic graft or patch material. There were 29 early graft infections (

Steroids are perhaps one of the most widely used group of drugs in present day anaesthetic practice, sometimes with indication and sometimes without indications. Because of their diverse effects on various systems of the body, there has been renewed interest in the use of steroids in modern day anaesthetic practice. This paper focuses on the synthesis and functions of steroids and risks associated with their supplementation. This paper also highlights the recent trends, relevance, and consensus issues on the use of steroids as adjunct pharmacological agents in relation to anaesthetic practice and intensive care, along with emphasis on important clinical aspects of perioperative usefulness and supplementation.

International audience; The SHIVA-ANR project aims at assessing the vulnerability of rural water users under stressors of global changes in the hard rocks area of South India. Determining present and future vulnerability of farmers to global changes calls for the creation of a context specific vulnerability index. A method is tested in small watershed of Gajwell (Andhra Pradesh).

Wind excited vibrations generated by the vortex shedding are very common in high-voltage overhead transmission lines. Although such vibrations are barely perceptible due to their low amplitudes (less than a conductor diameter), controlling them, however, is extremely important since they may lead to conductor fatigue. Mathematical models are therefore necessary for the computation of these vibrations, not only to evaluate the risk of potential damage to the transmission line but also for studying the efficiency of the damping measures. For single conductor transmission lines, the so-called energy-balance method gives fairly good results for the estimation of vibration amplitudes. However, the problem becomes more involved for the conductor bundles attached with different damping devices. A modified form of the energy-balance method is thus needed. This thesis presents a mathematical-mechanical model for modeling the vibrations of the conductor bundles with many spacer dampers and Stockbridge dampers, by considering subconductors as continuous systems. External damping devices are incorporated into the model by means of their complex impedance matrices. The presented model results in a smaller system matrix in comparison to what is obtained while modeling the conductor as a discrete system. This modeling procedure yields a complex non-polynomial transcendental eigen- value problem (TEVP). Solving such a TEVP is simple for smaller systems, e.g., for single conductor transmission lines. However, for a comparatively bigger system like the one in case of conductor bundles, it is a formidable task to obtain all the system eigenvalues in a certain frequency domain. The first goal of the presented thesis is to find e±cient numerical methods for obtaining the solutions of TEVPs. Different numerical techniques are discussed and their results are compared. Newton's approach for the solution of the eigenvalue problem is found to be an e±cient solution technique for obtaining the complex eigenvalues of a TEVP of the current type. After obtaining the complex eigenvalues and eigenmodes of the system, an energy balance principle is presented in order to obtain the actual vibration amplitudes in the subconductors. In energy balance the energy input from the wind is equated with the energy loss due to external damping and the conductor's self damping. Wind power input is normally obtained using data from the wind tunnel experiments or from the experiments carried out with transmission lines in the field, for laminar and turbulent wind speeds. Wind power input data is only available for single oscillating rods/cylinders, as obtaining such data via experiments for different configurations of multi-cylinders, is a difficult task. The second goal of the presented work is to numerically obtain the wind power input for the oscillating cylinders in a tandem arrangement. A finite-volume approach is used for the solution of the Navier-Stokes equations. Moving grids are used to incorporate the movements of the cylinders. Firstly, accuracy and feasibility of the numerical results are verified by solving the flow around a single cylinder, and comparing the obtained results with the available experimental data. For similar setups as used in the experiments from different researchers, numerical wind power input for a single oscillating cylinder is obtained. Good agreement with the experimental results is found. The numerical approach is subsequently further extended to obtain the wind power input for two oscillating cylinders in a tandem arrangement. A considerable difference between the wind power inputs for the downstream cylinder in a cylinder-tandem and for a single oscillating cylinder is observed. The newly obtained wind power input is utilized for the energy balancing in a bundled conductor benchmark problem, and results are discussed.

Study groups are common approaches for students to study together at schools. However, little is known about how this approach is suited to MOOC based learning, where learners watch and discuss MOOC lecture videos in a collaborative manner. Watching MOOCs with peers creates learning experiences that blend the way students learn in classroom with learning through a computer: Students get a chance to “pause” the professor as well as to discuss with other learners. In this paper, we explore this type of MOOC-based learning. Findings from our longitudinal study on spontaneous collocated MOOC study groups suggest that groups tend to stick to a certain kind of study style. A strong positive relationship was found between how often students pause and replay the videos and the synchronicity among groups. Further, synchronous groups tended to perceive better group learning experience, in terms of self-assessed quality and mutual participation. Future MOOC designers as well as schools that offer courses in a flipped classroom format can use the insights to provide guided support for group learners of MOOCs.

To investigate the relationship between occupants’ perception of control over building elements and their comfort, we conducted a study where two prototype office rooms were compared: while the first room allowed occupants to open or close the window and configure the shading, the second one was fully automated. The quantitative analysis of collected data a) supports the existing results in the literature reporting higher satisfaction where manual control is maintained, and b) uncovers a new impact of highly automated systems: lower control over building elements can increase the occupant’s consciousness of the environmental factors and the saliency of comfort parameters.

Shared artifacts, such as drawings and schemas on whiteboards, sticky-notes with ideas on walls, are often created and interacted with during meetings. These shared artifacts a) facilitate the expression of complex fleeting ideas, b) enable collaborators to establish a common ground and validate each others’ understanding about the context, and c) extend the validity of shared information by making it permanent. By the end of a collaboration session, the shared content denotes the shared knowledge amongst collaborators, which emerged as a result of a recursive process of storage, transformation, and retrieval from an external memory such as a whiteboard. Although these interactions with the artifacts symbolize the important episodes in a group discussion, still the information contained within them has not been much leveraged in collaboration research. Being well assimilated in the established work culture, collaborators do not heed the interactions with the shared artifacts, and therefore the nature of the social information contained within them is latent. However, from a research perspective this information is valuable and can offer insights into a few facets of ongoing group dynamics and processes. This thesis in particular a) identifies and examines the characteristics of the latent social information, b) studies the relationship of this information with different aspects of collaboration, and c) explores the practical utility of this information in collaboration assessment. We start by designing a meeting technology - MeetHub that enables collaborators to share and interact with artifacts in an unconstrained manner over a shared workspace, and allow us to collect fine-grained interactional information. Then we present user studies, where we extract and comprehend the relevant social information from interactions with the artifacts, and analyze its relationship with collaborative processes. Our findings demonstrate that latent social information is significantly correlated with the task outcome, division-of-labor, and the quality of mutual understanding between collaborators. Finally, we present a prediction system based on this social information, capable of alerting the group members about the poorly grounded episodes in real-time, and thus enabling them to regulate their collaborative behavior. The final contribution of this work presents itself as implications towards the dual nature of shared workspace, supporting the creation and sharing of artifacts as well as an assessment tool.

One of the main aims of Technology-Enhanced Learning (TEL) research is to aid in the design of educational technologies that are not only effective but also can contribute to the high-level theories of our field. Albeit design patterns or guidelines are not unheard of in TEL research, there is a scarcity of intermediate-level concepts that are not as generalizable as theories, but with an applicability wider than that of a single technology or intervention. This document reports on two focused analyses of TEL literature that investigate such scarcity. The evidence from our analysis illustrates the relative shortage of such intermediate-level contributions, and suggests that the TEL community needs a way to abstract knowledge from multiple design-based research processes, in a more explicit and systematic manner.

We report the results from an eye-tracking study to show the differences in gaze patterns across the MOOC learners, while they watch a lecture individually as well as when they collaborate on an add-on activity. 98 university students took part in a study where they watched the MOOC video individually and later they collaboratively constructed a concept map. In both phases the gaze data was recorded. We compute two gaze measures: (1) with-me-ness, to quantify how much students follow the teacher during the video lecture, (2) gaze similarity, to quantify how much the pair looks at the same set of objects while collaborating. The analysis shows that both of the measures correlate significantly with the learning outcome. We argue that these results, conforming to our previous findings, indicate that the proposed gaze measures give a fairly accurate proxy to learners’ engagement and performance.

Activating student knowledge (ASK) before receiving learning materials improves their learning outcome (Tormey and LeDuc (2014)). We implement ASK through priming by using two versions of the same pretest in a dual eye-tracking study in a MOOC context. We propose an additional activity, a collaborative concept-map, based on the MOOC lecture to enable the students to reflect on what they learnt. The priming affects the learning gain, individual and collaborative gaze patterns. Textual priming stands better than schema priming in terms of learning outcome. Finally, the pairs having participants with similar gaze to each other have more learning gain.

This chapter investigates the life cycle perfor- mance benefits of intensifying use of an of- fice environment, taking into account the im- pact on user comfort. It highlights the need to revisit how building performance should be measured — not per square meter as a functional unit but in terms of actual occupation through a user-centred approach, notably at the post-occupancy stage.

One of the main aims of Technology-Enhanced Learning (TEL) research is to aid in the design of educational technologies that are not only effective but also can contribute to the high-level theories of our field. Albeit design patterns or guidelines are not unheard of in TEL research, there is a scarcity of intermediate-level concepts that are not as generalizable as theories, but with an applicability wider than that of a single technology or intervention. This document reports on two focused analyses of TEL literature that investigate such scarcity. The evidence from our analysis illustrates the relative shortage of such intermediate-level contributions, and suggests that the TEL community needs a way to abstract knowledge from multiple design-based research processes, in a more explicit and systematic manner.

We report about two ongoing studies, which challenge the individualistic model of MOOC based learning. MOOC usage is embedded in the context of collocated study groups. The ability to pause a lecture and discuss its contents with peers creates learning opportunities. Learning by explaining has been proved effective through many empirical studies. We investigate the best way to configure these study groups with different tools.

This poster focuses on observing visually disabled user provided with smartphones featuring an accessible interface. The aim is then to create interaction modes fulfilling end users’ needs. This is the reason why we run user tests as part of our project development. These tests allowed us to highlight several elements that need be taken into account when building interfaces for sight-impaired people. Some interface adjustment, some graphic feature to tur into audio and tactile eature, with a clear and adequate use of sounds and vibrations, are mains pint to deal with., Ce poster porte sur les spécificités liées aux observations d’usage de personnes non-voyantes testant un téléphone tactile équipé d’une interface accessible. L’objectif de cette étude est d’ajuster les modes d’interactions afin qu’ils soient en cohérence avec les besoins des utilisateurs finaux. Les tests utilisateurs effectués pour cette étude mettent en lumière plusieurs éléments à prendre en compte lorsque l’on construit ce type d’interfaces. Notamment l’ajustement de l’interface selon le profil de l’utilisateur, l’équivalence audiotactile des éléments graphiques ainsi que la différenciation des retours sonores et vibratoires en fonction de leur nature.

The Taser Brain Journal stands as a defender of the human race, which entered a state of enslavement controlled by the Federal World Government (FWG) and the International Organization of the Digitial Identity (IODI). Across five fragments of the thoughts of citizens, dating from 2016 and recovered through negotiations, the newspaper allows readers to discover the questions and concerns of a lost society., The Taser Brain Journal se dresse comme défenseur de l’espèce humaine arrivée au stade d’asservissement contrôlé par la Federal World Government (FWG) et l’International Organization of the Digitial Identity (IODI). A travers cinq fragments de réflexions citoyennes datant de 2016 et récupérés au fil de négociations, le journal propose aux lecteurs de découvrir les interrogations et les préoccupations d’une société égarée.

This article presents basic principles for the conception of an interface dedicated to manipulating the moving image. After a general discussion on human-machine communication and the innovation process, we describe and compare 6 projects realized between 2001 and 2010 in the field of computational cinema., Cet article présente des principes de base pour la conception d'une interface destinée à manipuler l'image en mouvement. Après une discussion générale sur la communication homme-machine et le processus d'innovation, nous décrivons et comparons 6 projets réalisés entre 2001 et 2010 dans le domaine du cinéma computationnel.

Art installations that enable co-located collective interac- tions rarely call the execution of a task or a preannounced goal as a guideline for the activity. If this new configuration, which differs from those of traditional HCI, is revealed, from the perspective of aesthetic experience, to be one of the richest and most ’engaging’ ones, it is by no means less complex to apprehend for both the artist and the end-user. Through a case study (with concrete examples of artistic installations), we propose in this present article to exam- ine the topological configurations of existing co-localized collective interaction by analyzing the scope of actions of the systems’ agents and the relations between them. To achieve this, we lay the foundations of a new graphical lan- guage (used here to describe the relations between inter- faces), which we foresee to dedicate, in the near future, to the modeling, visual representation and taxonomic analysis of topologies of interaction., Les dispositifs artistiques mettant en oeuvre des interactions collectives co-localisées n'appellent que rarement l'exécution d'une tâche ou d'un objectif énoncé au préal-able servant de conducteur à l'activité. Si cette nouvelle configuration, qui se différencie de celles de l'IHM tradition-nelle, se révèle, du point de vue de l'expérience esthétique, l'une des plus riches et 'engageantes', elle n'en demeure pas moins complexe à appréhender (sur le plan perceptivo-cognitif) tant pour l'artiste que pour l'utilisateur final. Fort d'une étude de cas (exemples concrets d'installations artis-tiques), nous nous proposons au sein de ce présent article d'examiner quelques unes des configurations topologiques d'interaction collective co-localisée aujourd'hui à l'oeuvre en partant d'une analyse du champ d'action des agents du système et de leurs interactions. Pour ce faire, nous y je-tons les bases d'un nouveau langage graphique (ici utilisé pour décrire les relations d'interfaçage) que nous envis-ageons ultérieurement dédier à la modélisation, représen-tation et analyse taxonomique visuelle des topologies de l'interaction.

We used PR2 robot, in autonomous operation in a living lab setting, to provide an object search service to elderly volunteers (familiar to robots or naïve). Observation was complemented by semi-directed interviews. There was no significant difference between the groups either in the successful detection of the willingness to interact or the appreciation of voice interaction. This fosters dedicated HCI development for the elderly., Nous avons étudié l'interaction homme-robot, en fonctionnement autonome en environnement contrôlé, de PR2™ utilisé pour rechercher des objets avec des sujets âgés (avec ou sans expertise robotique). L'observation a été complétée d'entretiens semi-directifs. Il n'y a pas eu de différence significative entre ces deux groupes pour le succès de la détection d'intentionnalité et la perception de l'interaction vocale. Ce résultat est en faveur d'IHM prenant en compte les spécificités de la personne âgée.

Having social contacts and training the functional memory as well as the reasoning skills are fundamental activities for preventing the cognitive decline. In this article, we present a mobile app that aims at supporting intuitively these activities for older adults, exploiting the metaphor of a contact book., Les contacts sociaux et l'entrainement de la mémoire et des capacités cognitive logiques sont fondamentaux pour la prévention des troubles cognitifs légers. Dans cet article nous présentons une application mobile qui vise à supporter toutes ces activités de façon intuitive pour les seniors, grâce à la métaphore d'un carnet d'adresses.

This article presents a multimodal observation method of older people discovering the use of a smart house and tactile and spoken interaction modes inside a Living Lab. Our observation is based on ethnographic and numerical methods. We highlight the impact of presentation of the different technologies on the change of mind, the preference for voice interaction and some brakes considered as far as the adoption of new technologies is concerned., Cet article présente une méthode d’observation multimodale de personnes seniors découvrant l’utilisation d’un environnement domotisé et les techniques d’interaction tactile et vocale en Living Lab. L’observation repose sur des méthodes ethnographiques et numériques. Nous soulignons en particulier l’impact de la présentation des technologies sur le changement de regard que peuvent porter les participants de l’étude, la préférence de l’interaction vocale et quelques freins considérés comme très importants dans l’adoption des nouvelles technologies par les seniors.