Real-time crowd motion planning

Real-time crowd motion planning requires fast, realistic methods for path planning as well as obstacle avoidance. In a previous work (Morini et al. in Cyberworlds International Conference, pp. 144–151, 2007), we introduced a hybrid architecture to handle real-time motion planning of thousands of pedestrians. In this article, we present an extended version of our architecture, introducing two new features: an improved short-term collision avoidance algorithm, and simple efficient group behavior for crowds. Our approach allows the use of several motion planning algorithms of different precision for regions of varied interest. Pedestrian motion continuity is ensured when switching between such algorithms. To assess our architecture, several performance tests have been conducted, as well as a subjective test demonstrating the impact of using groups. Our results show that the architecture can plan motion in real time for several thousands of characters.

QFD: The problem of comparing technical/engineering design requirements

An approach based on multiple-criteria decision aid (MCDA) methods has been introduced for the prioritization of technical/engineering design requirements during the quality function deployment (QFD) process. The proposed method allows the avoidance of the rigid procedure under which the relationship matrix coefficients are turned from an ordinal into a cardinal scale. A comparison analysis is carried out between the traditional approach and the proposed one. A numerical example is also provided so as to highlight the main differences between the two methods.     

High-performance control of synchronous reluctance motors

Based on a (d,q) synchronous frame, the control problems of synchronous reluctance motors are outlined. In particular, the effect of magnetic saturation, core loss, and angular measurement errors of various types are evidenced. A flux-observer-based control scheme, capable of overcoming most of the above problems, is proposed. The proposed control has been implemented on a prototype drive, adopting a 17-N·m 8000-r/min motor. The experimental results show quite a good performance, with particular emphasis on those applications which require a large constant-power speed range     

Qualitative Ordinal Scales: The Concept of Ordinal Range

Many practical problems of quality control involve the use of ordinal scales. Questionnaires planned to collect judgments on qualitative or linguistic scales, whose levels are terms such as “good,” “bad,” “medium,” etc., are extensively used both in evaluating service quality and in visual controls for manufacturing industry. In an ordinal environment, the concept of distance between two generic levels of the same scale is not defined. Therefore, a population (universe) of judgments cannot be described using “traditional” statistical distributions since they are based on the notion of distance. The concept of “distribution shape” cannot be defined as well. In this article, we introduce a new statistical entity, the so-called ordinal distribution, to describe a population of judgments expressed on an ordinal scale. We also discuss which of the traditional location and dispersion measures can be used in this context and we briefly analyze some of their properties. A new dispersion measure, the ordinal range, as an extension of the cardinal range to ordinal scales, is then proposed. A practical application in the field of quality is developed throughout the article.     

PbS/CdS/ZnS Quantum Dots: A Multifunctional Platform for In Vivo Near‐Infrared Low‐Dose Fluorescence Imaging

Over the past decade, near‐infrared (NIR)‐emitting nanoparticles have increasingly been investigated in biomedical research for use as fluorescent imaging probes. Here, high‐quality water‐dispersible core/shell/shell PbS/CdS/ZnS quantum dots (hereafter QDs) as NIR imaging probes fabricated through a rapid, cost‐effective microwave‐assisted cation exchange procedure are reported. These QDs have proven to be water dispersible, stable, and are expected to be nontoxic, resulting from the growth of an outer ZnS shell and the simultaneous surface functionalization with mercaptopropionic acid ligands. Care is taken to design the emission wavelength of the QDs probe lying within the second biological window (1000–1350 nm), which leads to higher penetration depths because of the low extinction coefficient of biological tissues in this spectral range. Furthermore, their intense fluorescence emission enables to follow the real‐time evolution of QD biodistribution among different organs of living mice, after low‐dose intravenous administration. In this paper, QD platform has proven to be capable (ex vivo and in vitro) of high‐resolution thermal sensing in the physiological temperature range. The investigation, together with the lack of noticeable toxicity from these PbS/CdS/ZnS QDs after preliminary studies, paves the way for their use as outstanding multifunctional probes both for in vitro and in vivo applications in biomedicine.     

Upconversion in Er-doped Gd2O3 nanocrystals prepared by propellant synthesis and flame spray pyrolysis

In this study, monoclinic luminescent Gd₂O₃ nanocrystals doped with different concentrations of Er³⁺ (0.1, 1, and 10 mol%) were produced by propellant synthesis and flame spray pyrolysis (FSP). A comparison of their optical and morphological properties is reported. Following 980 nm excitation, an increase of the emission intensity from the ²H_11/2, ⁴S_3/2 → ⁴I_15/2 and ⁴F_9/2 → ⁴I_15/2 transitions was observed with increasing Er³⁺ concentration in the Gd₂O₃ nanocrystalline samples prepared via both techniques. However, the overall upconversion emission intensity was greater for the samples obtained by FSP. Furthermore, as the Er³⁺ concentration was increased, the intensity of the red (⁴F_9/2 → ⁴I_15/2) emission was observed to increase more rapidly in comparison to the green (²H_11/2, ⁴S_3/2 → ⁴I_15/2) emission resulting in an overall enhancement of the red component in the upconversion emission. Although both synthetic routes yield average crystallite sizes in the nanoscale, the TEM and SEM images confirm a more homogeneous morphology and lower particle aggregation for the nanocrystals produced by FSP.