443 research outputs found
Random Finite Set Theory and Optimal Control of Large Collaborative Swarms
Controlling large swarms of robotic agents has many challenges including, but
not limited to, computational complexity due to the number of agents,
uncertainty in the functionality of each agent in the swarm, and uncertainty in
the swarm's configuration. This work generalizes the swarm state using Random
Finite Set (RFS) theory and solves the control problem using Model Predictive
Control (MPC) to overcome the aforementioned challenges. Computationally
efficient solutions are obtained via the Iterative Linear Quadratic Regulator
(ILQR). Information divergence is used to define the distance between the swarm
RFS and the desired swarm configuration. Then, a stochastic optimal control
problem is formulated using a modified L2^2 distance. Simulation results using
MPC and ILQR show that swarm intensities converge to a target destination, and
the RFS control formulation can vary in the number of target destinations. ILQR
also provides a more computationally efficient solution to the RFS swarm
problem when compared to the MPC solution. Lastly, the RFS control solution is
applied to a spacecraft relative motion problem showing the viability for this
real-world scenario.Comment: arXiv admin note: text overlap with arXiv:1801.0731
7-Bromo-4-(7-bromo-3,3-dimethyl-1-oxo-2,3,4,9-tetrahydro-1H-xanthen-9-yl)-3,3-dimethyl-2,3-dihydroxanthen-1(4H)-one ethanol solvate
The title compound, C30H26Br2O4·C2H5OH, was synthesized from the reaction between 5-bromosalicybenzaldehyde and 5,5-dimethyl-1,3-cyclohexanedione. The crystal packing is stabilized by intermolecular O—H⋯O hydrogen bonds and C—H⋯O interactions
4-[(5-Chloro-3-methyl-1-phenyl-1H-pyrazol-4-yl)methylideneamino]-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one
In the molecule of the title compound, C22H20ClN5O, the atoms of the two pyrazole rings and the –C=N– group which joins them are essentially coplanar, with an r.m.s. deviation of 0.054 (2) Å. The phenyl rings form dihedral angles of 41.24 (5) and 55.53 (5)° with this plane. The crystal structure is stabilized by weak intermolecular π–π interactions, with centroid-to-centroid distances of 3.6179 (13) Å between the imidazole rings
Case report: Myocardial noncompaction causing massive cerebral infarction in 1 patient with eyelid edema as an early manifestation and literature review
ObjectiveTo summarize and analyze the early clinical manifestations, risk factors, treatment and prognosis of myocardial noncompaction in children, and to provide scientific basis for early and effective intervention.MethodsCombined with a case of myocardial noncompaction with massive cerebral infarction in a child, the related research reports of myocardial noncompaction in children were analyzed retrospectively.ResultsMyocardial noncompaction in children is cardiomyopathy caused by abnormal myocardial compaction during embryonic development. Feeding intolerance, dyspnea, chest tightness, fatigue, eyelid edema and other non-specific manifestations may occur in the early stage. It is easy to miss the diagnosis and misdiagnosis in clinical diagnosis and treatment, leading to intractable heart failure, nausea and arrhythmia, thromboembolism and even sudden death and other serious complications. Early diagnosis, symptomatic treatment, control of complications and regular follow-up can prevent the occurrence of serious complications and reduce mortality.ConclusionThere is no specific clinical manifestation in the early stage of myocardial noncompaction in children. If it is not detected early and treated symptomatically, the prognosis is poor and the mortality is high. Therefore, clinicians should fully improve the understanding of the early clinical manifestations of this disease, give early diagnosis and early intervention to children, reduce the occurrence of serious complications and improve the survival rate
1,5-Dimethyl-4-{[(3-methyl-5-oxo-1-phenyl-4,5-dihydro-1H-pyrazol-4-ylidene)(thiophen-2-yl)methyl]amino}-2-phenyl-1H-pyrazol-3(2H)-one
In the title compound, C26H23N5O2S, an intramolecular N—H⋯O interaction generates an S(6) ring. The essentially planar S(6) and pyrazole rings [maximum deviations = −0.0270 (14) and 0.0195 (15) Å, respectively] are nearly coplanar, making a dihedral angle of 3.94 (6)°. The S(6) ring makes dihedral angles of 23.79 (6), 78.53 (6) and 67.91 (6)° with the pyrazolone ring, the pyrazole ring and the benzene ring of antipyrine, respectively. The structure exhibits a thienyl-ring flip disorder with occupancy factors in the ratio 0.82:0.18
Remote Sensing Evidence for Significant Variations in the Global Gross Domestic Product during the COVID-19 Epidemic
Coronavirus disease 2019 (COVID-19) has been spreading rapidly and is still threatening human health currently. A series of measures for restraining epidemic spreading has been adopted throughout the world, which seriously impacted the gross domestic product (GDP) globally. However, details of the changes in the GDP and its spatial heterogeneity characteristics on a fine scale worldwide during the pandemic are still uncertain. We designed a novel scheme to simulate a 0.1° × 0.1° resolution grid global GDP map during the COVID-19 pandemic. Simulated nighttime-light remotely sensed data (SNTL) was forecasted via a GM(1, 1) model under the assumption that there was no COVID-19 epidemic in 2020. We constructed a geographically weighted regression (GWR) model to determine the quantitative relationship between the variation of nighttime light (ΔNTL) and the variation of GDP (ΔGDP). The scheme can detect and explain the spatial heterogeneity of ΔGDP at the grid scale. It is found that a series of policies played an obvious role in affecting GDP. This work demonstrated that the global GDP, except for in a few countries, represented a remarkably decreasing trend, whereas the ΔGDP exhibited significant differences
Heuristic Satisficing Inferential Decision Making in Human and Robot Active Perception
Inferential decision-making algorithms typically assume that an underlying
probabilistic model of decision alternatives and outcomes may be learned a
priori or online. Furthermore, when applied to robots in real-world settings
they often perform unsatisfactorily or fail to accomplish the necessary tasks
because this assumption is violated and/or they experience unanticipated
external pressures and constraints. Cognitive studies presented in this and
other papers show that humans cope with complex and unknown settings by
modulating between near-optimal and satisficing solutions, including
heuristics, by leveraging information value of available environmental cues
that are possibly redundant. Using the benchmark inferential decision problem
known as ``treasure hunt", this paper develops a general approach for
investigating and modeling active perception solutions under pressure. By
simulating treasure hunt problems in virtual worlds, our approach learns
generalizable strategies from high performers that, when applied to robots,
allow them to modulate between optimal and heuristic solutions on the basis of
external pressures and probabilistic models, if and when available. The result
is a suite of active perception algorithms for camera-equipped robots that
outperform treasure-hunt solutions obtained via cell decomposition, information
roadmap, and information potential algorithms, in both high-fidelity numerical
simulations and physical experiments. The effectiveness of the new active
perception strategies is demonstrated under a broad range of unanticipated
conditions that cause existing algorithms to fail to complete the search for
treasures, such as unmodelled time constraints, resource constraints, and
adverse weather (fog)
Herbal Medicine for Hot Flushes Induced by Endocrine Therapy in Women with Breast Cancer: A Systematic Review and Meta-Analysis
Objective. This systematic review was conducted to evaluate the clinical effectiveness and safety of herbal medicine (HM) as an alternative management for hot flushes induced by endocrine therapy in breast cancer patients. Methods. Key English and Chinese language databases were searched from inception to July 2015. Randomized Controlled Trials (RCTs) evaluating the effects of HM on hot flushes induced by endocrine therapy in women with breast cancer were retrieved. We conducted data collection and analysis in accordance with the Cochrane Handbook for Systematic Reviews of Interventions. Statistical analysis was performed with the software (Review Manager 5.3). Results. 19 articles were selected from the articles retrieved, and 5 articles met the inclusion criteria for analysis. Some included individual studies showed that HM can relieve hot flushes as well as other menopausal symptoms induced by endocrine therapy among women with breast cancer and improve the quality of life. There are minor side effects related to HM which are well tolerated. Conclusion. Given the small number of included studies and relatively poor methodological quality, there is insufficient evidence to draw positive conclusions regarding the objective benefit of HM. Additional high quality studies are needed with more rigorous methodological approach to answer this question
- …