The Effect of Integrating Travel Time

This contribution demonstrates the potential gain for the quality of results in a simulation of pedestrians when estimated remaining travel time is considered as a determining factor for the movement of simulated pedestrians. This is done twice: once for a force-based model and once for a cellular automata-based model. The results show that for the (degree of realism of) simulation results it is more relevant if estimated remaining travel time is considered or not than which modeling technique is chosen -- here force-based vs. cellular automata -- which normally is considered to be the most basic choice of modeling approach.Comment: preprint of Pedestrian and Evacuation 2012 conference (PED2012) contributio

March 1971 wind tunnel tests of the Dorand DH 2011 jet flap motor, volume 2

Wind tunnel tests were conducted of the Dorand DH 2011D jet flap rotor. The data recorded during the tests consist of: (1) multicyclic cam coefficients, (2) stress analysis, (3) vibratory loads, (4) Fourier analysis of flap deflection, and (5) blade bending stress. Data are presented in the form of tables and graphs

March 1971 wind tunnel tests of the Dorand DH 2011 jet flap rotor, volume 1

The results of wind tunnel tests, second series of tests performed in the NASA Ames 40 x 80 foot wind tunnel, of the DH 2011 jet-flap rotor are presented and analyzed. The tests have been focused on multicyclic effects and the capability of this rotor to reduce the vibratory loads and stresses in the blades. The reductions of the vibrations and stresses at tip speed ratio of 0.4 have attained 50%. The theory shows further reductions possible, reaching 80%. The results show that the performance characteristics after the modifications introduced since 1965 remained unchanged. The domain of investigation has been enlarged to include the tip speed ratios of 0.6 and 0.7. To analyze the complex aeroelastic phenomena a new analytical technique has been utilized to represent the mathematical model of the rotor. This technique, based on transfer matrices and transfer functions, appears very simple and it is believed that this analysis is applicable to many kinds of investigations involving large numbers of variables

Service oriented interactive media (SOIM) engines enabled by optimized resource sharing

In the same way as cloud computing, Software as a Service (SaaS) and Content Centric Networking (CCN) triggered a new class of software architectures fundamentally different from traditional desktop software, service oriented networking (SON) suggests a new class of media engine technologies, which we call Service Oriented Interactive Media (SOIM) engines. This includes a new approach for game engines and more generally interactive media engines for entertainment, training, educational and dashboard applications. Porting traditional game engines and interactive media engines to the cloud without fundamentally changing the architecture, as done frequently, can enable already various advantages of cloud computing for such kinds of applications, for example simple and transparent upgrading of content and unified user experience on all end-user devices. This paper discusses a new architecture for game engines and interactive media engines fundamentally designed for cloud and SON. Main advantages of SOIM engines are significantly higher resource efficiency, leading to a fraction of cloud hosting costs. SOIM engines achieve these benefits by multilayered data sharing, efficiently handling many input and output channels for video, audio, and 3D world synchronization, and smart user session and session slot management. Architecture and results of a prototype implementation of a SOIM engine are discussed

Multicyclic jet-flap control for alleviation of helicopter blade stresses and fuselage vibration

Results of wind tunnel tests of a 12 meter-diameter-rotor utilizing multicyclic jet-flap control deflection are presented. Analyses of these results are shown, and experimental transfer functions are determined by which optimal control vectors are developed. These vectors are calculated to eliminate specific harmonic bending stresses, minimize rms levels (a measure of the peak-to-peak stresses), or minimize vertical vibratory loads that would be transmitted to the fuselage. Although the specific results and the ideal control vectors presented are for a specific jet-flap driven rotor, the method employed for the analyses is applicable to similar investigations. A discussion of possible alternative methods of multicyclic control by mechanical flaps or nonpropulsive jet-flaps is presented

Characterizing correlations of flow oscillations at bottlenecks

"Oscillations" occur in quite different kinds of many-particle-systems when two groups of particles with different directions of motion meet or intersect at a certain spot. We present a model of pedestrian motion that is able to reproduce oscillations with different characteristics. The Wald-Wolfowitz test and Gillis' correlated random walk are shown to hold observables that can be used to characterize different kinds of oscillations

Stochastic Transition Model for Discrete Agent Movements

We propose a calibrated two-dimensional cellular automaton model to simulate pedestrian motion behavior. It is a v=4 (3) model with exclusion statistics and random shuffled dynamics. The underlying regular grid structure results in a direction-dependent behavior, which has in particular not been considered within previous approaches. We efficiently compensate these grid-caused deficiencies on model level.Comment: 8 pages, 4 figure

Modeling the desired direction in a force-based model for pedestrian dynamics

We introduce an enhanced model based on the generalized centrifugal force model. Furthermore, the desired direction of pedestrians is investigated. A new approach leaning on the well-known concept of static and dynamic floor-fields in cellular automata is presented. Numerical results of the model are presented and compared with empirical data.Comment: 14 pages 11 figures, submitted to TGF'1

Pedestrian Traffic: on the Quickest Path

When a large group of pedestrians moves around a corner, most pedestrians do not follow the shortest path, which is to stay as close as possible to the inner wall, but try to minimize the travel time. For this they accept to move on a longer path with some distance to the corner, to avoid large densities and by this succeed in maintaining a comparatively high speed. In many models of pedestrian dynamics the basic rule of motion is often either "move as far as possible toward the destination" or - reformulated - "of all coordinates accessible in this time step move to the one with the smallest distance to the destination". Atop of this rule modifications are placed to make the motion more realistic. These modifications usually focus on local behavior and neglect long-ranged effects. Compared to real pedestrians this leads to agents in a simulation valuing the shortest path a lot better than the quickest. So, in a situation as the movement of a large crowd around a corner, one needs an additional element in a model of pedestrian dynamics that makes the agents deviate from the rule of the shortest path. In this work it is shown, how this can be achieved by using a flood fill dynamic potential field method, where during the filling process the value of a field cell is not increased by 1, but by a larger value, if it is occupied by an agent. This idea may be an obvious one, however, the tricky part - and therefore in a strict sense the contribution of this work - is a) to minimize unrealistic artifacts, as naive flood fill metrics deviate considerably from the Euclidean metric and in this respect yield large errors, b) do this with limited computational effort, and c) keep agents' movement at very low densities unaltered

Sub 20 nm Short Channel Carbon Nanotube Transistors

Carbon nanotube field-effect transistors with sub 20 nm long channels and on/off current ratios of > 1000000 are demonstrated. Individual single-walled carbon nanotubes with diameters ranging from 0.7 nm to 1.1 nm grown from structured catalytic islands using chemical vapor deposition at 700 degree Celsius form the channels. Electron beam lithography and a combination of HSQ, calix[6]arene and PMMA e-beam resists were used to structure the short channels and source and drain regions. The nanotube transistors display on-currents in excess of 15 microA for drain-source biases of only 0.4 Volt.Comment: Nano Letters in pres