A Human Aware Mobile Robot Motion Planner

Robot navigation in the presence of humans raises new issues for motion planning and control when the humans must be taken explicitly into account. We claim that a human aware motion planner (HAMP) must not only provide safe robot paths, but also synthesize good, socially acceptable and legible paths. This paper focuses on a motion planner that takes explicitly into account its human partners by reasoning about their accessibility, their vision field and their preferences in terms of relative human-robot placement and motions in realistic environments. This planner is part of a human-aware motion and manipulation planning and control system that we aim to develop in order to achieve motion and manipulation tasks in the presence or in synergy with humans.     

A parallel coordinates style interface for exploratory volume visualization

We present a user interface, based on parallel coordinates, that facilitates exploration of volume data. By explicitly representing the visualization parameter space, the interface provides an overview of rendering options and enables users to easily explore different parameters. Rendered images are stored in an integrated history bar that facilitates backtracking to previous visualization options. Initial usability testing showed clear agreement between users and experts of various backgrounds (usability, graphic design, volume visualization, and medical physics) that the proposed user interface is a valuable data exploration tool.     

Teaching the theory of estimation and detection via a GSM radio interface Simulation

A new way to teach advanced undergraduate and graduate students the theory of estimation and detection is described. The paper shows that the global system mobile (GSM) radio interface is well suited to the teaching of estimation and detection theory because it entails the understanding and application of several concepts within estimation and detection, as well as information theory, signal processing, and radio-wave propagation. With GSM now a mature system with specifications available in the public domain, the students created an open-source (OS) GSM simulator, including all four modulation and coding schemes (MCS 1,2,3,4) with puncturing, a channel estimator, a minimum phase prefilter, a Max log maximum a posteriori probability (MAP) equalizer, and a convolutional decoder. Studying and understanding the theory of estimation and detection is now possible by creating algorithms for the simulator and evaluating the impact of the algorithm on the GSM block error rate (BLER). Several experiments that are possible with the simulator are described.     

What makes virtual agents believable?

In this paper we investigate the concept of believability and make an attempt to isolate individual characteristics (features) that contribute to making virtual characters believable. As the result of this investigation we have produced a formalisation of believability and based on this formalisation built a computational framework focused on simulation of believable virtual agents that possess the identified features. In order to test whether the identified features are, in fact, responsible for agents being perceived as more believable, we have conducted a user study. In this study we tested user reactions towards the virtual characters that were created for a simulation of aboriginal inhabitants of a particular area of Sydney, Australia in 1770 A.D. The participants of our user study were exposed to short simulated scenes, in which virtual agents performed some behaviour in two different ways (while possessing a certain aspect of believability vs. not possessing it). The results of the study indicate that virtual agents that appear resource bounded, are aware of their environment, own interaction capabilities and their state in the world, agents that can adapt to changes in the environment and exist in correct social context are those that are being perceived as more believable. Further in the paper we discuss these and other believability features and provide a quantitative analysis of the level of contribution for each such feature to the overall perceived believability of a virtual agent.     

On partitioning rectilinear polygons into star-shaped polygons

We present an algorithm for finding optimum partitions of simple monotone rectilinear polygons into star-shaped polygons. The algorithm may introduce Steiner points and its time complexity isO(n), wheren is the number of vertices in the polygon. We then use this algorithm to obtain anO(n logn) approximation algorithm for partitioning simple rectilinear polygons into star-shaped polygons with the size of the partition being at most six times the optimum.     

Characterization of medium- and low-temperature carbides in a low-carbon steel by internal friction

The formation of carbides during the aging of a quenched steel with mass contents of 0.04% carbon was investigated by means of internal friction by measuring the carbon Snoek peak height. The aging was carried out at different temperatures ranging from 40 to 350°C so that different types of carbides were formed. Low-temperature carbides develop after aging below 100°C. The Johnson-Mehl equation is applied to evaluate the kinetics of precipitation and re-dissolution of the different carbides. The solubility of carbon in ferrite is influenced by the pre-existing carbides, which is, in part, the reason for the variation of thermodynamic data in previous work.     

Effect of lead ions on lipids and antioxidant complex activity of Capsicum annuum L leaves,pericarp and seeds

The composition of the main lipid classes in leaves, pericarp and seeds of pepper (Capsicum annuum L), and the effect of seedlings immersion in lead and sodium acetate nutrient solutions were investigated. Lead ions accumulated mainly in leaves; in pericarp and seeds the concentration of lead was more than 10 times lower. The influence of lead ions on the leaf lipid composition was expressed most in the last stages of plant development. Treatment with lead acetate caused a decrease in the activity of the antioxidative complex in pepper seeds.     

Integrated Modeling of Anaerobic Fluidized Bed Bioreactor for Deicing Waste Treatment. II: Simulation and Experimental Studies

This paper examines the influence of bed segregation on the performance of an anaerobic fluidized bed bioreactor (AFBR) using both an integrated mathematical model previously described in Part I of this study, and experimental data obtained from a laboratory-scale AFBR continuous flow system and batch serum vial tests. Local hydrodynamics within the bed are shown to determine mixing intensities and patterns of bioparticles thereby controlling biofilm thickness and composition along the bed height. Results of the model simulations and the experimental data indicate that shallow biofilms that allow full substrate penetration are dominantly populated with faster growing micro-organisms. The internal mass transfer resistance in thicker biofilm significantly influences population distribution resulting in the increase of population of slower growing micro-organisms in a deeper layer of the biofilm. The serum bottle tests also confirm that microbial distribution inside a multispecies biofilm is determined by the hydrodynamic condition of the reactor. This study illustrates the importance of hydrodynamic regimes in the AFBR, and demonstrates the impact of bed segregation on bioparticle properties and total system performance.     

One‐dimensional photogeneration profiles in silicon solar cells with pyramidal texture

The key metric of surface texturing is the short‐circuit current J_sc. It depends on front surface transmittance, light trapping and the spatial profiles of photogeneration G and collection efficiency η_c. To take advantage of a one‐dimensional profile of η_c(ζ), where ζ is the shortest distance to the p–n junction, we determine G(ζ) via ray tracing. This permits rigorous optical assessment of common pyramidal textures for various cell designs. When ζ is small, G(ζ) is largest beneath regular inverted pyramids, upright pyramids (regular or random) and planar surfaces, respectively. This higher G(ζ) results in superior collection of generated carriers in front‐junction cells. In simulations of a conventional screen‐print cell, 92.0% of generated carriers are collected for inverted pyramids, compared to 91.4% for upright pyramids, and 90.0% for a planar surface. Higher efficiency and rear junction devices are analysed in the paper. Despite differences in G(ζ) beneath textures, inverted pyramids achieve the highest J_sc for all cell designs examined (marginally so for high‐efficiency rear‐contact cells) due to superior front surface transmittance and light trapping. We assess a common one‐dimensional model for photogeneration beneath textured surfaces. This model underestimates G(ζ) when ζ is small, and overestimates G(ζ) when ζ is large. As a result, the generation current determined is inaccurate for thin substrates. It can be computed to within 3% error for 250 µm thick substrates. However, errors in G(ζ) can lead to 7.5% inaccuracy in calculations of J_sc. Errors are largest for lower efficiency designs, in which collection efficiency varies through the substrate. Copyright © 2011 John Wiley & Sons, Ltd.