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Kinematic analysis of flexible bipedal robotic systems

Applied Mathematics and Mechanics(english edition) 2024年第5期45卷 795-818页

作者： r.FAZeL A.M.SHAFeI S.r.NeKOO Department of Mechanical engineering Shahid Bahonar University of KermanKerman ***Iran Departamento de Ingenieria de Sistemas y Automatica Escuela Técnica Superior de IngenieriaUniversidad de SevillaSeville 41092Spain

In spite of its intrinsic complexities,the passive gait of bipedal robots on a sloping ramp is a subject of interest for numerous *** distinguishes the present research from similar works is the consideration of flexibility in the constituent links of this type of robotic *** is not a far-fetched assumption because in the transient(impact)phase,due to the impulsive forces which are applied to the system,the likelihood of exciting the vibration modes increases ***,the human leg bones that are involved in walking are supported by viscoelastic muscles and ***,for achieving more exact results,it is essential to model the robot links with viscoelastic *** this end,the Gibbs-Appell formulation and Newton's kinematic impact law are used to derive the most general form of the system's dynamic equations in the swing and transient phases of *** most important issue in the passive walking motion of bipedal robots is the determination of the initial robot configuration with which the system could accomplish a periodic and stable gait solely under the effect of gravitational *** extremely unstable nature of the system studied in this paper and the vibrations caused by the impulsive forces induced by the impact of robot feet with the inclined surface are some of the very serious challenges encountered for achieving the above-mentioned *** overcome such challenges,an innovative method that uses a combination of the linearized equations of motion in the swing phase and the algebraic motion equations in the transition phase is presented in this paper to obtain an eigenvalue *** solving this problem,the suitable initial conditions that are necessary for the passive gait of this bipedal robot on a sloping surface are *** effects of the characteristic parameters of elastic links including the modulus of elasticity and the Kelvin-Voigt coefficient on the walking stability of this type of

关键词： bipedal robot flexible link swing phase transient phase eigenvalue problem Kelvin-Voigt coefficient

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FSCIL-eACA: Few-Shot Class-Incremental Learning Network Based on embedding Augmentation and Classifier Adaptation for Image Classification

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Chinese Journal of electronics 2024年第1期33卷 139-152页

作者： ruru ZHANG Haihong e Meina SONG School of Computer Science Beijing University of Posts and Telecommunications education Department Information Network engineering research Center Beijing University of Posts and Telecommunications

The ability to learn incrementally is critical to the long-term operation of AI systems. Benefiting from the power of few-shot class-incremental learning(FSCIL), deep learning models can continuously recognize new classes with only a few samples. The difficulty is that limited instances of new classes will lead to overfitting and exacerbate the catastrophic forgetting of the old classes. Most previous works alleviate the above problems by imposing strong constraints on the model structure or parameters, but ignoring embedding network transferability and classifier adaptation(CA), failing to guarantee the efficient utilization of visual features and establishing relationships between old and new classes. In this paper, we propose a simple and novel approach from two perspectives: embedding bias and classifier bias. The method learns an embedding augmented(eA) network with cross-class transfer and class-specific discriminative abilities based on self-supervised learning and modulated attention to alleviate embedding bias. Based on the adaptive incremental classifier learning scheme to realize incremental learning capability,guiding the adaptive update of prototypes and feature embeddings to alleviate classifier bias. We conduct extensive experiments on two popular natural image datasets and two medical datasets. The experiments show that our method is significantly better than the baseline and achieves state-of-the-art results.

关键词： Training Adaptation models Visualization Image recognition Prototypes Self-supervised learning Power capacitors

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Unmixing detrital zircon U-Pb ages reveals tectonic and climatic depositional influences on the Carboniferous Ansilta Formation,Calingasta-Uspallata Basin,Western Argentina

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Geoscience Frontiers 2024年第4期15卷 61-77页

作者： J.r.Malone J.e.Malone J.L.Isbell D.H.Malone J.P.Craddock K.N.Pauls Department of Geological Sciences Jackson School of GeosciencesUniversity of Texas at AustinAustinTX 78712USA Iowa Geological Survey University of IowaIowa CityIA 52240USA Department of Geosciences University of Wisconsin-MilwaukeeMilwaukeeWI 53211USA Department of Geography Geology and the EnvironmentIllinois State UniversityNormalIL 61790-4400USA

The Late Paleozoic Ice Age(LPIA)was a principal control of sedimentation across Gondwana from the late Devonian through early *** assess the hypothesis that glacial to interglacial transitions in western Argentina were the primary control influencing sediment routing patterns among the various Carboniferous-Permian basins in western *** Carboniferous Ansilta Formation consists of glaciomarine,nearshore,and fluvial systems deposited during the LPIA along the eastern margin of the Calingasta-Uspallata Basin in *** lower,glacially influenced succession of the Ansilta Formation records at least five glacial advances;the upper succession of consists of progradational shallow marine,deltaic,and fluvial *** combine 1225 new U-Pb zircon ages from six samples of the Carboniferous Ansilta Formation in the Calingasta-Uspallata Basin with 5864 U-Pb ages from 147 pub-lished samples in the detrital Pymix forward mixture model to characterize provenance *** the glacially influenced lower Ansilta Formation,sediment was derived locally from the Protoprecordillera,which was a prominent highland with alpine glaciers flowing west and east into the Calingasta-Uspallata and Paganzo basins,***,there was little or no connection between these two basins during Serpukhovian-Bashkirian *** fluvial/deltaic upper Ansilta had distal sediment sources in the Sierras ***,our results support the collapse of the Protoprecordillera topographic barrier,enabling drainage patterns connecting the Paganzo and Calingasta-Uspallata basins by late Pennsylvanian-early Permian time.

关键词： Late Paleozoic Ice Age Argentina Calingasta-Uspallata Basin Ansilta Formation Detrital zircon provenance

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Holographic dark energy in non-conserved gravity theory

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Communications in Theoretical Physics 2024年第4期76卷 126-133页

作者： H r Fazlollahi Institute of Gravitation and Cosmology Peoples Friendship University of Russia(RUDN University)6 Miklukho-Maklaya StMoscow117198Russia

recently, reconsidering the rastall idea T_(μ;νν)^(v)=α_(,μ) through relativistic thermodynamics gives a new form for the scalar field α which led us to construct modern modified theory of gravity debugged ‘non-conserved gravity theory’ Fazlollahi 2023 euro. Phys. J. C 83 923. This theory unlike other modified theories of gravity cannot directly explain the current acceleration expansion in the absence of the cosmological constant and or existence of other forms of dark energy. Hence, in this study we have reinvestigated holographic dark energy Ρ_(X)~H^(2) in the non-conserved theory of gravity. In this context, the density and pressure of dark energy depend on the non-conserved term and density of the dust matter field. As shown, due to non-conservation effects on large-scale structures, unlike the original holographic model, our model onsets an acceleration epoch for the current Universe satisfies observations. Moreover, the interaction and viscous scenarios are studied for this model.

关键词： non-conserved gravity covariant form of thermodynamics holographic dark energy

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The effect of the concentration of plastic waste on the formation of reaction products of the Ti–PeT system

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Green Chemical engineering 2024年第3期5卷 374-382页

作者： Aleksey e.Matveev Tomsk Scientific Center of the Siberian Branch of the russian Academy of Sciences

The paper presents research results of the synthesis, phase composition, and structure of products obtained by highly exothermic reactions between Ti and C10H8O4mixture components, depending on the plastic waste concentration and Ti powder dispersiveness, density of initial samples, and synthesis medium. The dependence of the phase composition and structure of the synthesis products on the concentration of the polymer（plastic）component in the initial Ti-PeT(C10H8O4) system was found. When the plastic waste content is 20 wt% to 25 wt%, synthesis products contain TiC0.5O0.5–TiC0.6–0.75particle agglomerates. Further growth in the polyethylene terephthalate content from 30 wt% to 45 wt% leads to the formation of synthesis products consisting of titanium carbide(TiC0.6–1.0). The gaseous byproduct composition of the exothermic reaction is investigated for the Ti–-C10H8O4mixture composition. It is found that the gaseous by-product mostly contains hydrogen and carbon monoxide as well as impurities of different hydrocarbons（methane, acetylene, ethane, ethene） and carbon dioxide. The maximum adiabatic temperature of the gas combustion temperature is 2080℃, which demonstrates the possibility of using gas as a fuel for energy generation devices. Based on the data obtained, it is possible to create a basis for a new plastic waste technology to fabricate carbide-containing materials.

关键词： Plastic waste Titanium carbide Green technology Hydrogen synthesis

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Blast injury risks to humans within a military trench

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Defence Technology（防务技术） 2024年第10期40卷 91-104页

作者： Idan e.edri National Building research Institute Technion-Israel Institute of TechnologyTechnion CityHaifa 32000Israel

In land warfare,trenches serve as vital defensive fortifications,offering protection to soldiers while engaging in ***,despite their protective function,soldiers often sustain injuries within these *** lack of corresponding blast data alongside empirical injury reports presents a significant knowledge gap,particularly concerning the blast pressures propagating within trench spaces following nearby *** absence hinders the correlation between blast parameters,trench geometry,and reported injury cases,limiting our understanding of blast-related risks within *** paper addresses the critical aspect of blast propagation within trench systems,essential for evaluating potential blast injury risks to individuals within these *** advanced computational fluid dynamics(CFD)simulations,the study comprehensively investigates blast injury risks resulting from explosions near military *** a sophisticated computational model,the research analyzes the dynamic blast effects within trenches,considering both geometrical parameters and blast characteristics influenced by explosive weight and scaled *** numerical simulations yield valuable insights into the impact of these parameters on blast injury risks,particularly focusing on eardrum rupture,lung injury,and traumatic brain injury levels within the *** findings elucidate distinct patterns of high-risk zones,highlighting unique characteristics of internal explosions due to confinement and venting dynamics along the *** study underscores the significance of detailed numerical modeling in assessing blast injury risks and provides a novel knowledge base for understanding risks associated with explosives detonating near military *** insights gained contribute to enhancing safety measures in both military and civilian contexts exposed to blast events near trench structures.

关键词： Trench Blast Injury risk eardrum rupture Lung injury Traumatic brain injury

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enhancing the clinical relevance of haemorrhage prediction models in trauma

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Military Medical research 2024年第3期11卷 467-468页

作者： Sankalp Tandle Jared M.Wohlgemut Max e.r.Marsden erhan Pisirir evangelia Kyrimi rebecca S.Stoner William Marsh Zane B.Perkins Nigel r.M.Tai Centre for Trauma Sciences Blizard InstituteQueen Mary University of LondonLondon E12ATUK The royal London Hospital Barts Health NHS TrustLondon E11FRUK Academic Department of Military Surgery and Trauma Research and Clinical InnovationThe Royal Centre for Defence MedicineBirmingham B152WBUK Department of electronic engineering and Computer Science Queen Mary University of LondonLondon E14NSUK

We read with interest the recent systematic reviewaArtificial intelligence and machine learning for hemorrhagic trauma careoby Peng et al.[1],which evaluated literature on machine learning(ML)in the management of trau... 详细信息

关键词： Trauma Injury Blood transfusion Massive transfusion Prediction Artificial intelligence Machine learning

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Post-operative protein supplementation following orthopaedic surgery: A systematic review

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Sports Medicine and Health Science 2024年第1期6卷 16-24页

作者： Andrew George Brendan M.Holderread Bradley S.Lambert Joshua D.harris Patrick C.McCulloch Houston Methodist Orthopedics and Sports Medicine 6445 Main Street Suite 2300HoustonTX77030USA Houston Methodist Orthopedic Biomechanics research Laboratory 6670 Bertner AveHoustonTX77030USA

Decreased mechanical loading after orthopaedic surgery predisposes patients to develop muscle *** purpose of this review was to assess whether the evidence supports oral protein supplementation can help decrease postoperative muscle atrophy and/or improve patient outcomes following orthopaedic surgery.A systematic review was conducted according to the Preferred reporting Items for Systematic reviews and MetaAnalysis(PrISMA).PubMed(MeDLINe),embase,Scopus,and Web of Science were searched for randomized controlled trials that assessed protein or amino acid supplementation in patients undergoing orthopaedic *** investigators independently conducted the search using relevant Boolean *** outcomes included functional or physiologic measures of muscle atrophy or *** studies including 611 patients(224 males,387 females)were *** studies evaluated protein supplementation after ACL reconstruction(ACLr),3 after total hip arthroplasty(THA),5 after total knee arthroplasty(TKA),and 3 after surgical treatment of hip *** supplementation showed beneficial effects across all types of *** primary benefit was a decrease in muscle atrophy compared to placebo as measured by muscle cross sectional *** authors also demonstrated improved functional measures and quicker achievement of rehabilitation *** supplementation has beneficial effects on mitigating muscle atrophy in the postoperative period following ACLr,THA,TKA,and surgical treatment of hip *** effects often correlate with improved functional measures and quicker achievement of rehabilitation *** research is needed to evaluate long-term effects of protein supplementation and to establish standardized population-specific regimens that maximize treatment efficacy in the postoperative period.

关键词： Orthopaedic surgery Protein supplementation Systematic review Muscle atrophy

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event-triggered H_(∞) consensus control for input-constrained multi-agent systems via reinforcement learning

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Control Theory and Technology 2024年第1期22卷 25-38页

作者： Jinxuan Zhang Chang-e ren College of Information engineering Capital Normal UniversityBeijing100089China

This article presents an event-triggered H_(∞) consensus control scheme using reinforcement learning (rL) for nonlinear second-order multi-agent systems (MASs) with control constraints. First, considering control constraints, the constrained H_(∞) consensus problem is transformed into a multi-player zero-sum game with non-quadratic performance functions. Then, an event-triggered control method is presented to conserve communication resources and a new triggering condition is developed for each agent to make the triggering threshold independent of the disturbance attenuation level. To derive the optimal controller that can minimize the cost function in the case of worst disturbance, a constrained Hamilton–Jacobi–Bellman (HJB) equation is defined. Since it is difficult to solve analytically due to its strongly non-linearity, reinforcement learning (rL) is implemented to obtain the optimal controller. In specific, the optimal performance function and the worst-case disturbance are approximated by a time-triggered critic network;meanwhile, the optimal controller is approximated by event-triggered actor network. After that, Lyapunov analysis is utilized to prove the uniformly ultimately bounded (UUB) stability of the system and that the network weight errors are UUB. Finally, a simulation example is utilized to demonstrate the effectiveness of the control strategy provided.

关键词： H_(∞)optimal control Input constrains Multi-agent systems(MASs) reinforcement learning(rL)

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Drone systems for delivering defibrillators for sudden cardiac arrests

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Journal of Acute Disease 2024年第1期13卷 1-2页

作者： Thirumurugan e edwin Dias Karthick r Srinivas University MangaloreKarnatakaIndia Faculty of Allied Health Science DR MGR Educational and Research InstituteACS Medical CollegeChennaiTamil NaduIndia

Unmanned aerial vehicles(UAVs),or drones,that were initially developed for military use during World War I[1],have evolved into highly sophisticated aircraft that can be navigated remotely using global positioning *** constant improvements,drones have become more efficient,and cost-effective,with longer battery life and greater loading ***,UAVs have proven to be an effective and affordable solution for enhancing healthcare accessibility for patients who face geographical or infrastructural *** drone networks can greatly reduce the time transporting life-saving equipment,such as delivering automated external defibrillators(AeDs),to cardiac arrest victims,and can provide quick assistance to reduce travel time for the patients.

关键词： initially travel battery

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