Robust trajectory tracking: differential game/cheap control approach

A robust trajectory tracking problem is treated in the framework of a zero-sum linear-quadratic differential game of a general type. For the cheap control version of this game, a novel solvability condition is derived. The sufficient condition, guaranteeing that the tracking problem is solved by the optimal strategy of the minimiser in the cheap control game, is established. The boundedness of the time realisations of this strategy is analysed. An illustrative example is presented.     

High-performance implementation of regular and easily scalable sorting networks on an FPGA

The paper is dedicated to fast FPGA-based hardware accelerators that implement sorting networks. The primary emphasis is on the uniformity of core components, feasible combinations of parallel, pipelined and sequential operations, and the regularity of the circuits and interconnections. The paper shows theoretically, and based on numerous experiments, that many existing solutions that are commonly considered to be very efficient have worthy competitors that are better for many practical problems. We compared the even–odd merge and bitonic merge sorting networks (which are among the fastest known) with the even–odd transition network, which is often characterized as significantly slower and more resource consuming. We found that the latter is the most regular network that can be implemented very efficiently in FPGA, so we are proposing new, easily scalable hardware solutions and processing techniques based on this. Finally, the paper provides four main contributions and suggests: (1) a regular hardware implementation of resource and time effective architectures based on the even–odd transition network; (2) a pipelined implementation of even–odd transition networks; (3) a pre-processing technique that enables sorting to be further accelerated; (4) combinations of this technique with a merge sort, an address-based sort, a quicksort, and a radix sort.     

Lidar and satellite temperature measurements during the sudden stratospheric warmings over Siberia and the Russian Far East in 2008–2012

This article presents a comprehensive study of disturbances of the temperature regime of the Earth’s stratosphere, which are related to sudden stratospheric warmings over Western and Eastern Siberia and the Russian Far East in the winters of 2008–2012. This study is based on data obtained using temperature remote-sensing techniques (lidar and satellite ones). The analysis rests on data on vertical temperature distribution in the stratosphere, obtained from lidar measurements over regions of Tomsk (56°N, 85°E), Yakutsk (61°N, 130°E), and Paratunka, the Kamchatka territory (53°N, 158°E). For complex analysis of the spatial–temporal temperature distribution in the middle atmosphere, the lidar measurement data are applied along with satellite data on temperature acquired by the microwave limb sounder on the Earth Observing System Aura satellite. We consider the regional effects of sudden stratospheric warmings that were observed over the Asian region of Russia (~85–160°E) in the winters of 2008–2012. There were stratospheric warmings over the Asian region of Russia each winter during the period under consideration, as deduced from lidar and satellite measurements of temperature. Lidar and satellite measurements of temperature have evidenced the previously known peculiarities of the development of winter stratospheric warmings. On the whole, lidar and satellite measurements of height distribution of temperatures agree. Possible reasons for the divergences under consideration are discussed.     

Behavior of Pendulums on a Regular Polygon

Stochastic and deterministic versions of a discrete dynamical network system are investigated. This network consists of a sequence of contours NSWE with nodes, which are common points atN, W, S and E. There are four cells and a particle on each contour At each time instance, the particle occupies a cell, and attempts to occupy the next cell in the same direction. Particles of neighboring contours move in accordance with some rules. Both deterministic and stochastic rules are considered. The behavior of the model with the first rule is stochastic only at the beginning, and after a time interval the system becomes to pure deterministic. The system with the second rule comes to a steady state, which depends on the initial state. The average velocity of particles and other characteristics of the system are studied.     

Inventive machine: Second generation

Inventive Machine project is the matter of discussion. The project aims to develop a family of AI systems for intelligent support of all stages of engineering design. Peculiarities of the IM project:

1. deep and comprehensive knowledge base — the theory of inventive problem solving (TIPS)
2. solving complex problems at the level of inventions
3. application in any area of engineering
4. structural prediction of engineering system development

The systems of the second generation are described in detail     

A design of waveguide elliptic filter based on resonant diaphragms with a complex aperture

A novel approach to the synthesis of waveguide band-pass elliptic filters on the transverse metal resonant diaphragms with the complex aperture is proposed. The aperture of the diaphragm is considered to be a rectangular window with two L-shaped metal ridges. For the complex conductivity of the diaphragm, we solve the corresponding electrodynamic problem. We also construct and investigate an equivalent circuit of the resonant diaphragm containing a series-parallel LC circuit. The geometry of the diaphragm aperture is found to be corresponding to the parameters of the equivalent circuit. We construct a third-order elliptic filter and provide a computer simulation of the diaphragms satisfying the amplitude-frequency characteristics of its resonators. We show that some resonators can be located on one complex resonant diaphragm, which then reduces the length of the filter. The band-pass filter for a rectangular waveguide WR137 is developed and manufactured. The central frequency of the filter is 6.6 GHz, the passband width 7.5 % with return loss of −20 dB, and the total length is 34 mm.     

历史城市与设计创新——俄罗斯天然气工业城概念性方案设计国际竞赛概述

2006年在俄罗斯圣彼得堡市进行的天然气工业城概念性方案设计国际竞赛,无论是项目本身还是参赛者名单都极具影响。在这样一座几个世纪来都严格遵守旧城保护政策的历史名城,建造现代理念的高层建筑吸引了众多国际建筑大师前来参与,他们的设计理念为圣彼得堡城市规划及建筑的发展带来了新的尝试与思考。本文对这次竞赛的过程及参赛方案进行了概要论述。     

Do Extracellular Vesicles Derived from Mesenchymal Stem Cells Contain Functional Mitochondria?

Extracellular vesicles (EV) derived from stem cells have become an effective complement to the use in cell therapy of stem cells themselves, which has led to an explosion of research into the mechanisms of vesicle formation and their action. There is evidence demonstrating the presence of mitochondrial components in EV, but a definitive conclusion about whether EV contains fully functional mitochondria has not yet been made. In this study, two EV fractions derived from mesenchymal stromal stem cells (MSC) and separated by their size were examined. Flow cytometry revealed the presence of mitochondrial lipid components capable of interacting with mitochondrial dyes MitoTracker Green and 10-nonylacridine orange; however, the EV response to the probe for mitochondrial membrane potential was negative. Detailed analysis revealed components from all mitochondria compartments, including house-keeping mitochondria proteins and DNA as well as energy-related proteins such as membrane-localized proteins of complexes I, IV, and V, and soluble proteins from the Krebs cycle. When assessing the functional activity of mitochondria, high variability in oxygen consumption was noted, which was only partially attributed to mitochondrial respiratory activity. Our findings demonstrate that the EV contain all parts of mitochondria; however, their independent functionality inside EV has not been confirmed, which may be due either to the absence of necessary cofactors and/or the EV formation process and, probably the methodology of obtaining EV.     

Green's Function for the Infinite Two-Dimensional Orthotropic Medium

The elastostatic Green's function (fundamental solution) for displacements of the two-dimensional infinite medium with orthotropic symmetry is derived in closed form in terms of elementary functions.