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Consensus controller for multi-UAV navigation

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Control Theory and Technology 2018年第2期16卷 110-121页

作者： patrik KOLARIC Ci CHEN Ankur DALAL Frank L. LEWIS UTA Research Institute University of Texas at Arlington 7300 Jack Newell Bird S Fort Worth TX 76118 U.S.A. School of Automation Guangdong University of Technology Guangdong Key Laboratory of loT Information Technology Guangzhou Guangzhou 510006 China State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang Liaoning 110819 China

In this paper, we design consensus algorithms for multiple unmanned aerial vehicles （UAV）. We mainly focus on the control design in the face of measurement noise and propose a position consensus controller based on the sliding mode control by using the distributed UAV information. Within the framework of Lyapunov theory, it is shown that all signals in the closed-loop multi- UAV systems are stabilized by the proposed algorithm, while consensus errors are uniformly ultimately bounded. moreover, for each local UAV, we propose a mechanism to define the trustworthiness, based on which the edge weights are tuned to eliminate negative influence from stubborn agents or agents exposed to extremely noisy measurement. Finally, we develop software for a nano UAV platform, based on which we implement our algorithms to address measurement noises in UAV flight tests. The experimental results validate the effectiveness of the proposed algorithms.

关键词： Consensus control multi-agent system quadrotor Lyapunov stability distributed system

Hot deformation of mg-Y-Zn alloy with a low content of the LPSO phase studied by in-situ synchrotron radiation diffraction

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Journal of magnesium and Alloys 2020年第1期8卷 199-209页

作者： Klaudia Horváth Fekete Daria Drozdenko Jan Capek Kristián máthis Domonkos Tolnai Andreas Stark Gerardo Garcés patrik Dobron Department of Physics of materials Faculty of Mathematics and PhysicsCharles UniversityKe Karlovu 512116 PragueCzech Republic Nuclear Physics Institute of the CAS 25068ˇRežCzech Republic magnesium Research Center Kumamoto University2-39-1 Kurokami Chuo-ku860-8555 KumamotoJapan Laboratory for Neutron Scattering and Imaging Paul Scherrer InstituteVilligen PSI5232Switzerland Institute of materials Science Helmholtz-Zentrum GeesthachtMax-Planck Str.1GeesthachtD21502Germany Department of Physical metallurgy CENIM-CSICAvenida Gregorio del Amo 8E-28040 MadridSpain

The compressive deformation behavior of the extruded WZ42(mg98.5Y1Zn0.5 in at.%)magnesium alloy containing a low amount of long-period stacking ordered(LPSO)phase was studied by in-situ synchrotron radiation diffraction *** were conducted at temperatures between room temperature and 350℃.Detailed microstructure investigation was provided by scanning electron microscopy,particularly the backscattered electron imaging and electron backscatter diffraction *** results show that twinning lost its dominance and kinking of the LPSO phase became more pronounced with increasing deformation *** cracks of the LPSO phase and no debonding r at the interface between the LPSO phase and the mg matrix were observed at temperatures above 200℃.At 350℃,the LPSO phase lost its strengthening effect and the deformation of the alloy was mainly realized by the dynamic recrystallization of the mg matrix.

关键词： magnesium alloy LPSO phase Kinking High temperature Synchrotron radiation diffraction

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The presence and partitioning behavior of flame retardants in waste,leachate,and air particles from Norwegian waste-handling facilities

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Journal of Environmental Sciences 2017年第12期29卷 115-132页

作者： Nicolas A.O.morin patrik L.Andersson Sarah E.Hale Hans Peter H.Arp Norwegian Geotechnical Institute(NGI) P.O.Box 3930Ulleval StadionN-0806 OsloNorway Environmental and Food Laboratory of Vendee(LEA V) Department of ChemistryRond-point Georges Dural CS 8080285021 La Roche-sur-YonFrance Chemistry Department Umed UniversitySE-901 87 UmeaSweden

Flame retardants in commercial products eventually make their way into the waste *** the presence of flame retardants in Norwegian landfills, incineration facilities and recycling sorting/defragmenting facilities is investigated. These facilities handled waste electrical and electronic equipment（WEEE）, vehicles, digestate, glass, combustibles, bottom ash and fly ash. The flame retardants considered included polybrominated diphenyl ethers（∑BDE-10） as well as dechlorane plus, polybrominated biphenyls, hexabromobenzene,pentabromotoluene and pentabromoethylbenzene（collectively referred to as ∑FR-7）. Plastic,WEEE and vehicles contained the largest amount of flame retardants（∑BDE-10： 45,000–210,000 μg/kg; ∑FR-7： 300–13,000 μg/kg）. It was hypothesized leachate and air concentrations from facilities that sort/defragment WEEE and vehicles would be the highest. This was supported for total air phase concentrations（∑BDE-10： 9000–195,000 pg/m^3 WEEE/vehicle facilities, 80–900 pg/m^3 in incineration/sorting and landfill sites）, but not for water leachate concentrations（e.g., ∑BDE-10： 15–3500 ng/L in WEEE/Vehicle facilities and 1–250 ng/L in landfill sites）. Landfill leachate exhibited similar concentrations as WEEE/vehicle sorting and defragmenting facility leachate. To better account for concentrations in leachates at the different facilities, waste-water partitioning coefficients, Kwastewere measured（for the first time to our knowledge for flame retardants）. WEEE and plastic waste had elevated Kwastecompared to other wastes, likely because flame retardants are directly added to these materials. The results of this study have implications for the development of strategies to reduce exposure and environmental emissions of flame retardants in waste and recycled products through improved waste management practices.

关键词： Brominated flame retardants Waste management Environmental emissions Atmospheric emissions Partitioning Leachate

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Production and decay of polarized hyperon-antihyperon pairs

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Chinese Physics C 2023年第5期 35-54页

作者： Karin Sch?nning Varvara Batozskaya patrik Adlarson 周小蓉 Department of Physics and Astronomy Uppsala University Uppsala Institute of High Energy Physics Chinese Academy of Sciences National Centre for Nuclear Research University of Science and Technology of China

Polarized hyperon-antihyperon pairs shed light on various unresolved puzzles in contemporary physics:How the strong interaction confines quarks into hadrons, how accurately the Standard model describes microcosmos and even why our universe consists of so much more matter than antimatter. Thanks to their weak, parity violating decays, hyperons reveal their spin properties. This can be exploited e.g. the decomposition of the electromagnetic structure of hyperons, precision tests of flavour symmetry and searches for CP violation. At the BESⅢ experiment at BEPC-Ⅱ, Beijing, China, hyperon-antihyperon pairs can be produced in abundance. Recently collected large data samples have triggered the development of new methods that provide unprecedented precision and a plethora of new results have emerged. When applied at future high-intensity facilities like PANDA and STCF, precision physics will be taken to a new level which can contribute to the solution to the aforementioned puzzles.

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Testing Thermal Properties of Cooling Device with Heat Pipes to Improve His Heat Transfer Ability

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Journal of Energy and Power Engineering 2014年第2期8卷 209-216页

作者： patrik Nemec Alexander Caja milan malcho Department of Power Engineering Faculty of Mechanical Engineering University of Zilina Zilina 01026 Slovakia

This paper deals about testing thermal properties of the cooling device with heat pipes at inclination position, in consequence of using the natural convection to improve heat transfer properties. Head point testing of cooling device is monitoring temperature on the aluminium block of energy converter, heat pipes and ribs under temperature condition 30 ℃ in thermostatic chamber. Testing of the device was performed at tilt angles positions 0, 10 and 20° from the vertical level. The heat flux loaded to energy converter was 450 W. The next goal of the paper is to research on influence working position of the wick heat pipe on their thermal performance. In this research heat pipes were made with capillary structure sintered from copper powder granularity 100, 63 and 50 μm filled with water and ethanol. Next heat pipe thermal performance was performed by measuring heat source and working positions. Knowledge of these two research goals can bring potential improvements in purpose of cooling device for effective heat sink from high power electronic components.

关键词： Heat pipe heat transfer cooling device.

Smoothed Particle Hydrodynamic modelling of Hydraulic Jumps: Bulk Parameters and Free Surface Fluctuations

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Engineering（科研） 2016年第6期8卷 386-402页

作者： Patrick Jonsson Pär Jonsén patrik Andreasson T. Staffan Lundström J. Gunnar I. Hellström Department of Engineering Sciences and mathematics Lule&aring University of Technology Lule&aring Sweden

A hydraulic jump is a rapid transition from supercritical flow to subcritical flow characterized by the development of large scale turbulence, surface waves, spray, energy dissipation and considerable air entrainment. Hydraulic jumps can be found in waterways such as spillways connected to hydropower plants and are an effective way to eliminate problems caused by high velocity flow, e.g. erosion. Due to the importance of the hydropower sector as a major contributor to the Swedish electricity production, the present study focuses on Smoothed Particle Hydrodynamic (SPH) modelling of 2D hydraulic jumps in horizontal open channels. Four cases with different spatial resolution of the SPH particles were investigated by comparing the conjugate depth in the subcritical section with theoretical results. These showed generally good agreement with theory. The coarsest case was run for a longer time and a quasi-stationary state was achieved, which facilitated an extended study of additional variables. The mean vertical velocity distribution in the horizontal direction compared favorably with experiments and the maximum velocity for the SPH-simulations indicated a too rapid decrease in the horizontal direction and poor agreement to experiments was obtained. Furthermore, the mean and the standard deviation of the free surface fluctuation showed generally good agreement with experimental results even though some discrepancies were found regarding the peak in the maximum standard deviation. The free surface fluctuation frequencies were over predicted and the model could not capture the decay of the fluctuations in the horizontal direction.

关键词： SPH Hydraulic Jump Conjugate Depth Free Surface Fluctuation Vertical Velocity Distribution

Why ecosystem characteristics predicted from remotely sensed data are unbiased and biased at the same time-and how this affects applications

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Forest Ecosystems 2024年第1期11卷 24-31页

作者： Goran Ståhl Terje Gobakken Svetlana Saarela Henrik J.Persson magnus Ekstrom Sean P.Healey Zhiqiang Yang Johan Holmgren Eva Lindberg Kenneth Nystrom Emanuele Papucci patrik Ulvdal Hans OleØrka Erik Næsset Zhengyang Hou Håkan Olsson Ronald E.mcRoberts Department of Forest Resource management Swedish University of Agricultural Sciences90183UmeåSweden Faculty of Environmental Sciences and Natural Resource management Norwegian University of Life SciencesÅsNorway USDA Forest Service Rocky Mountain Research StationOgdenUTUSA The Key Laboratory for Silviculture and Conservation of ministry of Education Beijing Forestry UniversityBeijing100083China Department of Forest Resources University of MinnesotaSt.PaulMNUSA

Remotely sensed data are frequently used for predicting and mapping ecosystem characteristics,and spatially explicit wall-to-wall information is sometimes proposed as the best possible source of information for ***,wall-to-wall information typically relies on model-based prediction,and several features of model-based prediction should be understood before extensively relying on this type of *** such feature is that model-based predictors can be considered both unbiased and biased at the same time,which has important implications in several areas of *** this discussion paper,we first describe the conventional model-unbiasedness paradigm that underpins most prediction techniques using remotely sensed(or other)auxiliary *** this point of view,model-based predictors are typically ***,we show that for specific domains,identified based on their true values,the same model-based predictors can be considered biased,and sometimes severely *** suggest distinguishing between conventional model-bias,defined in the statistical literature as the difference between the expected value of a predictor and the expected value of the quantity being predicted,and design-bias of model-based estimators,defined as the difference between the expected value of a model-based estimator and the true value of the quantity being *** show that model-based estimators(or predictors)are typically design-biased,and that there is a trend in the design-bias from overestimating small true values to underestimating large true ***,we give examples of applications where this is important to acknowledge and to potentially make adjustments to correct for the design-bias *** argue that relying entirely on conventional model-unbiasedness may lead to mistakes in several areas of application that use predictions from remotely sensed data.

关键词： Bias model-based inference Design-based inference

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Synthesis,Characterizations and in Vitro Assessment of the Cytotoxicity and Genotoxicity of Novel Silicon Nitride-Based Porous Ceramics

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materials Sciences and Applications 2013年第7期4卷 407-418页

作者： miroslav Hnatko Zoltán Lences Peter Copan Lucia Birosová patrik m.tejov Sona Jantová Department of Ceramic Institute of Inorganic ChemistrySlovak Academy of SciencesBratislavaSlovakia Institute of Inorganic Chemistry Technology and MaterialsFaculty of Chemical and Food TechnologySlovak University of TechnologyBratislavaSlovakia Institute of Biochemistry Nutrition and Health ProtectionFaculty of Chemical and Food TechnologySlovak University of TechnologyBratislavaSlovakia

Porous Si3N4-SiO2-based ceramics with different porosity were prepared via free sintering of Si3N4 on air with an addition of semolina (5, 10 and 20 wt%) as a pore-forming agent. The semolina content in the starting powder controlled the volume fraction of pores in the sintered body. Small pores (5 μm) formed a continuous network in the whole volume of the ceramic material, while the large pores (~100 μm), formed from the added semolina were mostly isolated in the ceramic matrix. mercury porosimetry and strength measurements have shown that specific surface area, volume density and compressive strength decreased with the amount of semolina in the samples. mechanical properties similar to bone were obtained for the sample with 20 wt% semolina pore forming agent (compressive strength 350 mPa, density 2.17 ***-3). The prepared Si3N4-SiO2-based ceramics were evaluated for cytotoxic and genotoxic potential on human fibroblast VH10 and B-HNF-1 cells. Biological tests have shown that both these human fibroblast cell lines were sensitive to the samples with lower porosity and cell growth inhibition was observed in the range 14.9% - 21.3%. The cytotoxicity of the sample with the highest porosity (~40%) was not significant (10%). The microscopic observations have shown that VH10 and B-HNF-1 cells growing around the silicon nitride ceramic discs were homogeneously distributed on the cultivation surface. No significant morphologic changes were found in treated cells, their morphology was very similar to that of the control cells. None of the tested Si3N4-based ceramic samples induced necrotic/apoptotic death of human fibroblasts. Sample S-20 had similar properties to bones and was characterized by very good biocompatibility, slight cytotoxicity and none genotoxicity. Therefore, Si3N4-SiO2-based ceramics prepared by free sintering on air are potential biomaterials for medical applications.

关键词： Silicon Nitride Sintering Porosity mechanical Properties Cytotoxicity/Genotoxicity Human Cell Lines

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光影之间

建筑实践 2014年第5期 34-39页

作者：李莹 Tord-Rikard Sderstrm patrik Lindell Ola Fogelstrm Wingrdhs

位于瑞典北部斯德哥尔摩的卡罗林斯卡医学院是瑞典著名的医学院,校门普通,校园内红色建筑群平实、方正,这个看上去朴素得像厂区一样的地方,如同群山般静默,不事张扬地偏于一隅,却以国际领先的科研水平和评审颁发诺贝尔生理学或医学奖闻... 详细信息

位于瑞典北部斯德哥尔摩的卡罗林斯卡医学院是瑞典著名的医学院,校门普通,校园内红色建筑群平实、方正,这个看上去朴素得像厂区一样的地方,如同群山般静默,不事张扬地偏于一隅,却以国际领先的科研水平和评审颁发诺贝尔生理学或医学奖闻名于世。不可思议的是,自1 940年建校以来,卡罗林斯卡医学院就从未建造一所大礼堂。学校一直都有建造大礼堂的想法,随着学校的扩张与排名的上升,师生数量均有所增加,却无法将其大规模聚集到一起。新千年伊始,学院获得一笔捐助,使建造一座渴盼已久的大礼堂成为可能。

关键词：卡罗林斯卡医学院建筑形态大礼堂立面玻璃窗玻璃幕墙建筑物光影报告厅诺贝尔平面布局