Comparison of 2D and 3D GUI Widgets for Stereoscopic Multitouch Setups

Recent developments in the area of interactive entertainment have suggested to combine stereoscopic visualization with multi-touch displays, which has the potential to open up new vistas for natural interaction with interactive three-dimensional (3D) applications. However, the question arises how the user interfaces for system control in such 3D setups should be designed in order to provide an effective user experience. In this article we introduce 3D GUI widgets for interaction with stereoscopic touch displays. The design of the widgets was inspired to skeuomorphism and affordances in such a way that the user should be able to operate the virtual objects in the same way as their real-world equivalents. We evaluate the developed widgets and compared them with their 2D counterparts in the scope of an example application in order to analyze the usability of and user behavior with the widgets. The results reveal differences in user behavior with and without stereoscopic display during touch interaction, and show that the developed 2D as well as 3D GUI widgets can be used effectively in different applications.

Estimating Gesture Accuracy in Motion-Based Health Games

This manuscript details a technique for estimating gesture accuracy within the context of motion-based health video games using the MICROSOFT KINECT. We created a physical therapy game that requires players to imitate clinically significant reference gestures. Player performance is represented by the degree of similarity between the performed and reference gestures and is quantified by collecting the Euler angles of the player's gestures, converting them to a three-dimensional vector, and comparing the magnitude between the vectors. Lower difference values represent greater gestural correspondence and therefore greater player performance. A group of thirty-one subjects was tested. Subjects achieved gestural correspondence sufficient to complete the game's objectives while also improving their ability to perform reference gestures accurately.

Simulating Wind and Warmth in Virtual Reality: Conception, Realization and Evaluation for a CAVE Environment

Wind and warmth sensations proved to be able to enhance users' state of presence in Virtual Reality applications. Still, only few projects deal with their detailed effect on the user and general ways of implementing such stimuli. This work tries to fill this gap: After analyzing requirements for hardware and software concerning wind and warmth simulations, a hardware and also a software setup for the application in a CAVE environment is proposed. The setup is evaluated with regard to technical details and requirements, but also - in the form of a pilot study - in view of user experience and presence. Our setup proved to comply with the requirements and leads to satisfactory results. To our knowledge, the low cost simulation system (approx. 2200 Euro) presented here is one of the most extensive, most flexible and best evaluated systems for creating wind and warmth stimuli in CAVE-based VR applications.

A Comparative Evaluation of Three Skin Color Detection Approaches

Skin segmentation is a challenging task due to several influences such as unknown lighting conditions, skin colored background, and camera limitations. A lot of skin segmentation approaches were proposed in the past including adaptive (in the sense of updating the skin color online) and non-adaptive approaches. In this paper, we compare three skin segmentation approaches that are promising to work well for hand tracking, which is our main motivation for this work. Hand tracking can widely be used in VR/AR e.g. navigation and object manipulation. The first skin segmentation approach is a well-known non-adaptive approach. It is based on a simple, pre-computed skin color distribution. Methods two and three adaptively estimate the skin color in each frame utilizing clustering algorithms. The second approach uses a hierarchical clustering for a simultaneous image and color space segmentation, while the third approach is a pure color space clustering, but with a more sophisticated clustering approach. For evaluation, we compared the segmentation results of the approaches against a ground truth dataset. To obtain the ground truth dataset, we labeled about 500 images captured under various conditions.

Influence of Comfort on 3D Selection Task Performance in Immersive Desktop Setups

Immersive virtual environments (IVEs) have the potential to afford natural interaction in the three-dimensional (3D) space around a user. However, interaction performance in 3D mid-air is often reduced and depends on a variety of ergonomics factors, the user's endurance, muscular strength, as well as fitness. In particular, in contrast to traditional desktop-based setups, users often cannot rest their arms in a comfortable pose during the interaction. In this article we analyze the impact of comfort on 3D selection tasks in an immersive desktop setup. First, in a pre-study we identified how comfortable or uncomfortable specific interaction positions and poses are for users who are standing upright. Then, we investigated differences in 3D selection task performance when users interact with their hands in a comfortable or uncomfortable body pose, while sitting on a chair in front of a table while the VE was displayed on a headmounted display (HMD). We conducted a Fitts' Law experiment to evaluate selection performance in different poses. The results suggest that users achieve a significantly higher performance in a comfortable pose when they rest their elbow on the table.

Influence of Information and Instructions on Human Behavior in Tunnel Accidents: A Virtual Reality Study

Human behavior is a major factor modulating the consequences of road tunnel accidents. We investigated the effect of information and instruction on drivers' behavior as well as the usability of virtual environments to simulate such emergency situations. Tunnel safety knowledge of the general population was assessed using an online questionnaire, and tunnel safety behavior was investigated in a virtual reality experiment. Forty-four participants completed three drives through a virtual road tunnel and were confronted with a traffic jam, no event, and an accident blocking the road. Participants were randomly assigned to a control group (no intervention), an informed group who read a brochure containing safety information prior to the tunnel drives, or an informed and instructed group who read the same brochure and received additional instructions during the emergency situation. Informed participants showed better and quicker safety behavior than the control group. Self-reports of anxiety were assessed three times during each drive. Anxiety was elevated during and after the emergency situation. The findings demonstrate problematic safety behavior in the control group and that knowledge of safety information fosters adequate behavior in tunnel emergencies. Enhanced anxiety ratings during the emergency situation indicate external validity of the virtual environment.

Advanced luminance control and black offset correction for multi-projector display systems

In order to display a homogeneous image using multiple projectors, differences in the projected intensities must be compensated. In this paper, we present novel approaches to combine and extend existing techniques for edge blending and luminance harmonization to achieve a detailed luminance control. Furthermore, we apply techniques for improving the contrast ratio of multi-segmented displays also to the black offset correction. We also present a simple scheme to involve the displayed context in the correction process to dynamically improve the contrast in brighter images. In addition, we present a metric to evaluate the different methods and their influence on the visual quality.

Performing AIDS. The Film-maker Rosa von Praunheim between HIV/AIDS-Communities in Germany and the USA

This paper explores the works of German film-maker Rosa von Praunheim during the AIDS crisis. In the 1980ies and 1990ies he produced several films portraying the gay communities in Germany and the USA in the face of AIDS. First, this paper analyses the cinematic techniques von Praunheim uses to criticise the German gay community and present the American practices of performing community as a role model for AIDS-activism. In a second step, the focus is put on von Praunheim’s autobiography and the rhetoric strategies he uses to participate in New York’s HIV-community, while being HIV-negative himself.

Performing AIDS. The Film-maker Rosa von Praunheim between HIV/AIDS-Communities in Germany and the USA

The paper explores the works of German film-maker Rosa von Praunheim during the AIDS crisis, who worked in Germany and the USA in the 1980ies and 1990ies and produced several films portraying the gay communities in both countries in the face of AIDS. The first part of the paper analyses how von Praunheim’s films show different forms of performing community in the two countries. It discusses the filmic techniques utilized to criticize the reaction of the German gay community to the appearance of AIDS and to present Amercian traditions of forming and performing a community as a role model for AIDS-activism. The second part focuses on von Praunheim’s autobiography „40 Years of Perversity. The Sentimental Memoirs of Rosa von Raunheim“ (1993) and the rhetoric strategies he – being HIV-negative himself – uses to become part of New York’s HIV-community. The paper examines the hypothesis that von Praunheim’s rhetoric is constructing and performing a „participative identity“ (Alois Hahn). The paper finally discusses the use and adaption of terms and symbols originating from the context of German National Socialism (e.g. the pink triangle) within the process of forming and performing New York’s AIDS-Community and how they are reused and readapted by Rosa von Praunheim.

Von der Lust, im fremden Körper zu denken - offene Manipulation im zeitgenössischen Sprechtheater

Figurentheater für ein erwachsenes Publikum findet vermehrt auch auf den institutionalisierten Bühnen des Sprech-, Tanz- und Musiktheaters statt. Diese Entwicklung steht symptomatisch für eine in allen Künsten beobachtbare Tendenz, Genre- und Formgrenzen zu öffnen. Mit der Auflösung strikter Grenzziehungen zwischen den Künsten sowie der Enthierarchisierung der Theatermittel in postdramatischen Formen werden mittlerweile verstärkt auch in Schauspielinszenierungen Puppen, die gleichberechtigt neben den menschlichen Darsteller_innen agieren, eingesetzt (z. B. Frankenstein, Regie: Philipp Stölzl, Theater Basel 2014; Die Brüder Löwenherz, Regie: Ingo Berk, Puppen: Mervyn Millar, Schauspielhaus Zürich 2014; Der Untergang des Hauses Usher, Regie und Puppen: Suse Wächter, Residenztheater München 2015; Merlin oder das wüste Land, Regie: Jan-Christoph Gockel, Puppen: Michael Pietsch, Schauspielhaus Graz 2015). Der seit etwa 20 Jahren beobachtbare massive Entwicklungsschub im west- und zentraleuropäischen Figurentheater ist eng verknüpft mit der Form der offenen Manipulation, bei der Puppenspieler_innen sichtbar die Spielfigur animieren. Inspiriert ist diese offene Spielweise vom traditionellen japanischen Figurentheater Bunraku, bei dem drei sichtbare Puppenspieler eine Figur animieren. Das Bühnengeschehen wird von einem am Seitenrand der Bühne platzierten Rezitator, welcher die Handlung erzählt und den Text aller Figuren spricht, sowie von einem Shamisen-Spieler begleitet. Während für Vertreter der historischen Avantgarde wie beispielsweise Edward Gordon Craig die Puppe aufgrund ihrer Kontrollierbarkeit als Schauspielerersatz von Interesse war, rückt im zeitgenössischen, offen manipulierenden Figurentheater der Fokus auf die Konfrontation von menschlichen Darsteller_innen und Kunstkörpern. Der Beitrag möchte das evidente Interesse der zeitgenössischen Theaterpraxis an der figurentheaterspezifischen Spielweise der offenen Manipulation zum Ausgangspunkt nehmen, um deren Potenzial zur Fragmentierung, Collagierung und Hybridisierung von Körperkonstruktionen und Körperdarstellungen sowie die damit einhergehenden Fragen nach Subjekt- versus Objektstatus zu untersuchen. Abschliessend soll der Frage nachgegangen werden, welche tradierten schauspieltheoretischen Setzungen mit Blick auf die Möglichkeiten der offenen Manipulation als theatrale Praktik im Sprechtheater einer Revision unterzogen werden müssen.

Neocortical hyperexcitability defect in a mutant mouse model of spike-wave epilepsy, {\it stargazer}

Single-locus mutations in mice can express epileptic phenotypes and provide critical insights into the naturally occurring defects that alter excitability and mediate synchronization in the central nervous system (CNS). One such recessive mutation (on chromosome (Chr) 15), stargazer(stg/stg) expresses frequent bilateral 6-7 cycles per second (c/sec) spike-wave seizures associated with behavioral arrest, and provides a valuable opportunity to examine the inherited lesion associated with spike-wave synchronization.^ The existence of distinct and heterogeneous defects mediating spike-wave discharge (SWD) generation has been demonstrated by the presence of multiple genetic loci expressing generalized spike-wave activity and the differential effects of pharmacological agents on SWDs in different spike-wave epilepsy models. Attempts at understanding the different basic mechanisms underlying spike-wave synchronization have focused on $\gamma$-aminobutyric acid (GABA) receptor-, low threshold T-type Ca$\sp{2+}$ channel-, and N-methyl-D-aspartate receptor (NMDA-R)-mediated transmission. It is believed that defects in these modes of transmission can mediate the conversion of normal oscillations in a trisynaptic circuit, which includes the neocortex, reticular nucleus and thalamus, into spike-wave activity. However, the underlying lesions involved in spike-wave synchronization have not been clearly identified.^ The purpose of this research project was to locate and characterize a distinct neuronal hyperexcitability defect favoring spike-wave synchronization in the stargazer brain. One experimental approach for anatomically locating areas of synchronization and hyperexcitability involved an attempt to map patterns of hypersynchronous activity with antibodies to activity-induced proteins.^ A second approach to characterizing the neuronal defect involved examining the neuronal responses in the mutant following application of pharmacological agents with well known sites of action.^ In order to test the hypothesis that an NMDA receptor mediated hyperexcitability defect exists in stargazer neocortex, extracellular field recordings were used to examine the effects of CPP and MK-801 on coronal neocortical brain slices of stargazer and wild type perfused with 0 Mg$\sp{2+}$ artificial cerebral spinal fluid (aCSF).^ To study how NMDA receptor antagonists might promote increased excitability in stargazer neocortex, two basic hypotheses were tested: (1) NMDA receptor antagonists directly activate deep layer principal pyramidal cells in the neocortex of stargazer, presumably by opening NMDA receptor channels altered by the stg mutation; and (2) NMDA receptor antagonists disinhibit the neocortical network by blocking recurrent excitatory synaptic inputs onto inhibitory interneurons in the deep layers of stargazer neocortex.^ In order to test whether CPP might disinhibit the 0 Mg$\sp{2+}$ bursting network in the mutant by acting on inhibitory interneurons, the inhibitory inputs were pharmacologically removed by application of GABA receptor antagonists to the cortical network, and the effects of CPP under 0 Mg$\sp{2+}$aCSF perfusion in layer V of stg/stg were then compared with those found in +/+ neocortex using in vitro extracellular field recordings. (Abstract shortened by UMI.) ^

Desde adentro del libro de Job : la lectura como clave de interpretación en tres textos tardíos de Osvaldo Horacio Dondo

Este trabajo consta, fundamentalmente, de dos partes bien diferenciadas. En la primera, se ubica al poeta Osvaldo Horacio Dondo (1902-1962) en el marco de las letras argentinas, cosa que se juzga necesaria, ya que hasta la década del 60 estuvo en la alta estima de muchos, pero luego cayó en el olvido generalizado. Su lugar es peculiar y representativo de aquellos que, habiéndose iniciado en el martinfierrismo, luego siguieron diversos derroteros; en este caso, el de la llamada vanguardia católica. Dondo es en sí mismo digno de ser considerado, como atestigua la autoridad de un Ara y la de un Aguirre, dos de los principales antólogos de la poesía argentina. El rescate de este autor será hecho, por un lado, teniendo en cuenta las antologías en tanto contracara ineludible de la historia de la literatura, de acuerdo con el ya canónico artículo de Alfonso Reyes (1952). Por otro lado, en la segunda parte, se ensaya un abordaje de su escritura desde el ángulo de la lectura como fenómeno complejo, que en cierta medida constituye un rasgo esencial del homo faber, además de actuar a modo de clave de interpretación de sus textos, especialmente los tardíos.

La joven vanguardia filosófica argentina de la década de 1920

La vanguardia filosófica de la “nueva generación" argentina de la década de 1920 no ha sido objeto, como tal, de investigaciones precedentes, y el artículo comienza con una discusión al respecto. Se traza luego un panorama de las disputas ideológicas de la época, especialmente en Inicial, la revista donde mejor se expresó esa vanguardia filosófica. Las restantes secciones del artículo se abocan a sus filósofos más representativos: Miguel Ángel Virasoro, Vicente Fatone, Carlos Astrada y Ángel Vassallo. Se cotejan sus conceptos sobre la crisis de Occidente y la misión histórica de la nueva generación. Pero el espiritualismo y el vitalismo característicos de sus planteos se observan luego también en sus críticas al tomismo y al positivismo, así como en sus reivindicaciones sobre la integralidad del espíritu, y en otras cuestiones metafísicas y políticas. Se señalan, finalmente, las principales direcciones posibles para más amplias investigaciones.

Horizontal profiles of longwave and shortwave radiation components over sea ice near Barrow, Alaska during the 2011 melt

An integrated instrument package for measuring and understanding the surface radiation budget of sea ice is presented, along with results from its first deployment. The setup simultaneously measures broadband fluxes of upwelling and downwelling terrestrial and solar radiation (four components separately), spectral fluxes of incident and reflected solar radiation, and supporting data such as air temperature and humidity, surface temperature, and location (GPS), in addition to photographing the sky and observed surface during each measurement. The instruments are mounted on a small sled, allowing measurements of the radiation budget to be made at many locations in the study area to see the effect of small-scale surface processes on the large-scale radiation budget. Such observations have many applications, from calibration and validation of remote sensing products to improving our understanding of surface processes that affect atmosphere-snow-ice interactions and drive feedbacks, ultimately leading to the potential to improve climate modelling of ice-covered regions of the ocean. The photographs, spectral data, and other observations allow for improved analysis of the broadband data. An example of this is shown by using the observations made during a partly cloudy day, which show erratic variations due to passing clouds, and creating a careful estimate of what the radiation budget along the observed line would have been under uniform sky conditions, clear or overcast. Other data from the setup's first deployment, in June 2011 on fast ice near Point Barrow, Alaska, are also shown; these illustrate the rapid changes of the radiation budget during a cold period that led to refreezing and new snow well into the melt season.

Export of algal biomass from the melting Arctic sea ice

In the Arctic, under-ice primary production is limited to summer months and is not only restricted by ice thickness and snow cover but also by the stratification of the water column, which constrains nutrient supply for algal growth. RV Polarstern visited the ice-covered Eastern Central basins between 82 to 89°N and 30 to 130°E in summer 2012 when Arctic sea ice declined to a record minimum. During this cruise, we observed a widespread deposition of ice algal biomass of on average 9 g C per m**2 to the deep-sea floor of the Central Arctic basins. Data from this cruise will contribute to assessing the impact of current climate change on Arctic productivity, biodiversity, and ecological function.