Handling congestion in crowd motion modeling

We address here the issue of congestion in the modeling of crowd motion, in the non-smooth framework: contacts between people are not anticipated and avoided, they actually occur, and they are explicitly taken into account in the model. We limit our approach to very basic principles in terms of behavior, to focus on the particular problems raised by the non-smooth character of the models. We consider that individuals tend to move according to a desired, or spontanous, velocity. We account for congestion by assuming that the evolution realizes at each time an instantaneous balance between individual tendencies and global constraints (overlapping is forbidden): the actual velocity is defined as the closest to the desired velocity among all admissible ones, in a least square sense. We develop those principles in the microscopic and macroscopic settings, and we present how the framework of Wasserstein distance between measures allows to recover the sweeping process nature of the problem on the macroscopic level, which makes it possible to obtain existence results in spite of the non-smooth character of the evolution process. Micro and macro approaches are compared, and we investigate the similarities together with deep differences of those two levels of description

The changing role and positions of the PRС in Asia-Pacific 1999–2007

В статье рассмотрены политические и экономические шаги Китайской Народной Республики в Азиатско-Тихоокеанском регионе в период с 1999 по 2007 г., приведшие, в частности, к изменению существующего баланса сил между КНР и США. Причины успешного укрепления влияния в данном регионе проанализированы в рамках снижения внешнеполитической активности на данном направлении Соединенных Штатов. Большое внимание уделено политике Китая по поиску новых партнеров и интеграции в экономические организации.The article is devoted to political and economic action of the People’s Republic of China in Asia-Pacific during the period from 1999 to 2007, which specifically changed current balance of power between the PRK and the USA. Reasons of successful strengthening of influence in the region have been analyzed in the context of decreasing of the foreign policy activity of the United States in this direction. Significant attention has been paid to the Chinese attempts of searching new partners and integration in economic organizations

Evaluation of atlas-based segmentation of hippocampi in healthy humans

Introduction and aim: Region of interest (ROI)-based functional magnetic resonance imaging (fMRI) data analysis relies on extracting signals from a specific area which is presumed to be involved in the brain activity being studied. The hippocampus is of interest in many functional connectivity studies for example in epilepsy as it plays an important role in epileptogenesis. In this context, ROI may be defined using different techniques. Our study aims at evaluating the spatial correspondence of hippocampal ROIs obtained using three brain atlases with hippocampal ROI obtained using an automatic segmentation algorithm dedicated to the hippocampus. Material and methods: High-resolution volumetric T1-weighted MR images of 18 healthy volunteers (five females) were acquired on a 3T scanner. Individual ROIs for both hippocampi of each subject were segmented from the MR images using an automatic hippocampus and amygdala segmentation software called SACHA providing the gold standard ROI for comparison with the atlas-derived results. For each subject, hippocampal ROIs were also obtained using three brain atlases: PickAtlas available as a commonly used software toolbox; automated anatomical labeling (AAL) atlas included as a subset of ROI into PickAtlas toolbox and a frequency-based brain atlas by Hammers et al. The levels of agreement between the SACHA results and those obtained using the atlases were assessed based on quantitative indices measuring volume differences and spatial overlap. The comparison was performed in standard Montreal Neurological Institute space, the registration being obtained with SPM5 (http://www.fil.ion.ucl.ac.uk/spm/). Results: The mean volumetric error across all subjects was 73% for hippocampal ROIs derived from AAL atlas; 20% in case of ROIs derived from the Hammers atlas and 107% for ROIs derived from PickAtlas. The mean false-positive and false-negative classification rates were 60% and 10% respectively for the AAL atlas; 16% and 32% for the Hammers atlas and 6% and 72% for the PickAtlas. Conclusion: Though atlas-based ROI definition may be convenient, the resulting ROIs may be poor representations of the hippocampus in some studies critical to under- or oversampling. Performance of the AAL atlas was inferior to that of the Hammers atlas. Hippocampal ROIs derived from PickAtlas are highly significantly smaller, and this results in the worst performance out of three atlases. It is advisable that the defined ROIs should be verified with knowledge of neuroanatomy before using it for further data analysis

Multilevel Analysis of Oscillation Motions in Active Regions of the Sun

We present a new method that combines the results of an oscillation study made in optical and radio observations. The optical spectral measurements in photospheric and chromospheric lines of the line-of-sight velocity were carried out at the Sayan Solar Observatory. The radio maps of the Sun were obtained with the Nobeyama Radioheliograph at 1.76 cm. Radio sources associated with the sunspots were analyzed to study the oscillation processes in the chromosphere-corona transition region in the layer with magnetic field B=2000 G. A high level of instability of the oscillations in the optical and radio data was found. We used a wavelet analysis for the spectra. The best similarities of the spectra of oscillations obtained by the two methods were detected in the three-minute oscillations inside the sunspot umbra for the dates when the active regions were situated near the center of the solar disk. A comparison of the wavelet spectra for optical and radio observations showed a time delay of about 50 seconds of the radio results with respect to optical ones. This implies a MHD wave traveling upward inside the umbral magnetic tube of the sunspot. Besides three-minute and five-minute ones, oscillations with longer periods (8 and 15 minutes) were detected in optical and radio records.Comment: 17 pages, 9 figures, accepted to Solar Physics (18 Jan 2011). The final publication is available at http://www.springerlink.co

Progress in Atomic Fountains at LNE-SYRTE

We give an overview of the work done with the Laboratoire National de M\'etrologie et d'Essais-Syst\`emes de R\'ef\'erence Temps-Espace (LNE-SYRTE) fountain ensemble during the last five years. After a description of the clock ensemble, comprising three fountains, FO1, FO2, and FOM, and the newest developments, we review recent studies of several systematic frequency shifts. This includes the distributed cavity phase shift, which we evaluate for the FO1 and FOM fountains, applying the techniques of our recent work on FO2. We also report calculations of the microwave lensing frequency shift for the three fountains, review the status of the blackbody radiation shift, and summarize recent experimental work to control microwave leakage and spurious phase perturbations. We give current accuracy budgets. We also describe several applications in time and frequency metrology: fountain comparisons, calibrations of the international atomic time, secondary representation of the SI second based on the 87Rb hyperfine frequency, absolute measurements of optical frequencies, tests of the T2L2 satellite laser link, and review fundamental physics applications of the LNE-SYRTE fountain ensemble. Finally, we give a summary of the tests of the PHARAO cold atom space clock performed using the FOM transportable fountain.Comment: 19 pages, 12 figures, 5 tables, 126 reference

VARIOUS METHODS OF CONSTRUCTING CONTROLS FOR A MANIPULATION ROBOT

Relay controls for a manipulation robot are considered. Various procedures are proposed for their construction for the criteria of the manipulator operation, determined by the speed and energy consumption. Comparison of the mixed criteria of the robot's work for various controls is given

Comparison of Relay and Impulse Control of Manipulator

Analytical formulas for impulse control of a simplified model of manipulator are obtained. Analytical formulas for quality indicators of impulse and relay controls are revealed. Areas allowing to compare the quality of relay and impulse controls are constructed on the base of control parameters.Работа выполнена при финансовой поддержке РНФ (Проект № 22-21-00714)

New trends of institutional changes in the system of technical regulation of the consumer goods quality in EAEU

Objective to evaluate the promising directions of exportreexport of consumer goods quality assessment institutions in the EAEU space taking into account the implementation of a modern approach to sectoral regulation. nbsp Methods the study uses the methods and tools of institutional analysis in particular the analysis of mormative and organizational aspects of the technical regulation systems functioning in the EU and EAEU countries. nbsp Results Over the past two decades numerous institutional changes have taken place in the system of quality standards for consumer goods. Despite these changes the system of standards has significant shortcomings largely associated with the need to take into account the interests of a narrow circle of ldquoinfluence groupsrdquo and the irrational consumer behavior. The turning point in the current situation which can be observed today is due to the operational transformation the complication of the organizational structure of standardization within the country and the development of digital technologies and the consumer cultural transformation. The analysis of the EAEU technical regulation system showed a contradiction between the quality regulation procedures in the subsystem of regulation certification and quality control. Based on the analysis of modern approaches to assessing the quality of consumer goods at the state level the authors propose an improved institutional design of the technical regulation system of the consumer goods quality. It is also found that regardless of the results of monitoring within the Eurasian space the formation of national standards with reference to the standards of other countries is the most probable option for institutional changes in the sphere of technical regulation. nbsp Scientific novelty the study offers recommendations for improving the system of formal institutions for monitoring the consumer goods quality that includes defining the principles and developing an algorithm for monitoring the consumer goods quality taking into account the current trends in the development of the technical regulation system of consumer goods quality in the EAEU. nbsp Practical significance the results obtained can be used by the Eurasian Economic Commission as well as by national bodies for standardization and certification when developing and justifying the strategy of the technical regulation system development