The Two-Point Visual Control Model of Steering - New Empirical Evidence

Abstract. Formal models of human steering behavior can enhance our understanding of perceptual and cognitive processes involved in lateral control. One such model is the two-point visual control model of steering proposed by Salvucci and Gra

Intersection Complexity and Its Influence on Human Drivers

As mixed traffic between automated vehicles and human drivers in inner city becomes more prevalent in the near future understanding and predicting drivers’ behavior is important. Additionally, there is a wide variety of inner city intersections. They can differ greatly in traffic density, visibility, number of objects and many more aspects. This difference in complexity has an influence on the behavior of human drivers at intersections. To further understand the effect of complexity we conducted a naturalistic driving field study in inner city traffic with 34 participants. We focused on unsignalized intersections because there is a greater range of possibly ambiguous situations at such intersections than compared to e.g. an intersection regulated by traffic lights. Features describing the behavior (commit distance, drop in velocity and the minimal velocity) are extracted from the driven trajectories. Additionally, we define intersection complexity by several features describing an intersection. These features include both the static (street, visible and driveable width, the visibility of the other streets and the number of trees) and the dynamic environment (entry location and turning direction, numbers of vehicles, vehicles with interaction, vehicles with priority, vehicles having to yield and pedestrians). Based on those we show that the entry location and the turning direction have a significant effect on the behavior features. Additionally, we show that the typical behavior of human drivers can be predicted by the features describing an intersection’s complexity. Finally, the feature set is reduced in dimensionality for a more condensed intersection description. For that we test reduced feature sets as well as feature sets from an autoencoder and show that prediction is feasible with them as well

Altering an Artificial Gagpolnef Polyprotein and Mode of ENV Co-Administration Affects the Immunogenicity of a Clade C HIV DNA Vaccine

HIV-1 candidate vaccines expressing an artificial polyprotein comprising Gag, Pol and Nef (GPN) and a secreted envelope protein (Env) were shown in recent Phase I/II clinical trials to induce high levels of polyfunctional T cell responses; however, Env-specific responses clearly exceeded those against Gag. Here, we assess the impact of the GPN immunogen design and variations in the formulation and vaccination regimen of a combined GPN/Env DNA vaccine on the T cell responses against the various HIV proteins. Subtle modifications were introduced into the GPN gene to increase Gag expression, modify the expression ratio of Gag to PolNef and support budding of virus-like particles. I.m. administration of the various DNA constructs into BALB/c mice resulted in an up to 10-fold increase in Gag- and Pol-specific IFNγ+ CD8+ T cells compared to GPN. Co-administering Env with Gag or GPN derivatives largely abrogated Gag-specific responses. Alterations in the molar ratio of the DNA vaccines and spatially or temporally separated administration induced more balanced T cell responses. Whereas forced co-expression of Gag and Env from one plasmid induced predominantly Env-specific T cells responses, deletion of the only H-2d T cell epitope in Env allowed increased levels of Gag-specific T cells, suggesting competition at an epitope level. Our data demonstrate that the biochemical properties of an artificial polyprotein clearly influence the levels of antigen-specific T cells, and variations in formulation and schedule can overcome competition for the induction of these responses. These results are guiding the design of ongoing pre-clinical and clinical trials

Evaluation of a vibrotactile feedback device for spatial guidance

In the present study, a vibrotactile feedback device for spatial guidance was evaluated in a tracking task paradigm. Participants (N = 18) had to translate and rotate virtual objects according to the vibrotactile vs. verbal cues without visual information. Both types of spatial guidance were evaluated using objective performance data (i.e. speed, accuracy) as well as subjective judgments. Results indicate that distinguishing spatial cues during the translational task was more difficult when being guided by vibrotactile feedback compared to verbal feedback. Nevertheless, individuals with vibrotactile guidance showed better performance at rotational tasks. Implications for the further design process and other areas of application are discussed

Evaluation zweier Bedienkonzepte zur Steuerung eines Fahrzeugs mit drei Bewegungsfreiheitsgraden

Neuartige Konzepte für Elektromobilität sehen vor, dass das Fahrzeug über vier unabhängig voneinander lenkbare Radnabenmotoren angetrieben wird (fourwheel independent steering, 4WIS). Dabei ergeben sich durch die mechanische Entkopplung von Lenk- bzw. Antriebsaktuatorik und Stellteilen (X-by-Wire) völlig neue Möglichkeiten zur Gestaltung der Mensch-Maschine-Schnittstelle. Ein Bedienkonzept für ein 4WIS-Fahrzeug sollte eine intuitive und sichere Nutzung der zusätzlichen Bewegungsfreiheitsgrade (Seitwärtsfahrt, Rotationen auf der Stelle, etc.) ermöglichen. Angeregt durch die Entwicklungen in der Luftfahrt, wurden auch im Automobilbereich erste Konzepte zur Steuerung mit Joystick-ähnlichen Stellteilen, sogenannten Sidesticks, vorgelegt (z.B. Eckstein, 2001). Neuere Studien liefern dabei erste Hinweise, dass die Sidestick-Steuerung verglichen mit dem konventionellen Steuerkonzept (Lenkrad, Pedalerie) mindestens gleich gute Fahrleistungen bei tendenziell geringerer Beanspruchung ermöglicht (Weber et al., 2011). In der vorliegenden Studie wurden zwei Bedienkonzepte zur Steuerung eines Fahrzeugs mit drei Bewegungsfreiheitsgraden (Longitudinal-, Lateral- und Gierbewegung) untersucht. Dabei wurde eine integrierte Steuerung mit einem 3DoF Sidestick mit einer auf einen 2DoF Sidestick und eine Spacemouse verteilten Steuerung verglichen. Die Ergebnisse der durchgeführten Fahrsimulationsstudie (N=16) weisen darauf hin, dass der Sidestick eine bessere Lateralsteuerung (Seitwärts-, Schrägfahrten) ermöglicht, wohingegen Giermanöver (Rotations-, Kurvenfahrten) besser mit der zusätzlichen Spacemouse gefahren werden können. Weitere Entwicklungen des Bedienkonzepts werden auf Basis der bisherigen Befunde diskutiert