106 research outputs found

    The Role Of The Ventromedial Prefrontal Cortex In Value-Based Decision-Making

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    The ventromedial prefrontal cortex (vmPFC) has been shown to correlate with the subjective value for options, across reward type and across hundreds of functional neuroimaging studies. Despite the prominence of its role in preference-based decision-making, its specific contributions to how decisions are made have not yet been well-characterised. Study 1 addresses what the vmPFC signal represents during decision-making. While the vmPFC signal has been shown to correlate highly with subjective value in past studies, this signal is also consistent with mental navigation through a conceptual attribute space using a grid-like code. We found that the mental navigation model lacked support in the evidence, and the subjective value model remains the best explanation for vmPFC signal during decision-making. After having established that the signal in vmPFC reflects subjective value, Study 2 addresses whether subjective value representations remain consistent for non-choice preference tasks, and when this representation comes online during the decision process. This study shows that the value network seen previously for choice tasks also is active during a matching bidding task, and that the vmPFC, interestingly, represents value only at the time of the final choice. Finally, in Study 3, I address the question of how the vmPFC is necessary for subjective value in my third chapter. Transitivity (the idea that if A \u3e B, and B \u3e C, then A \u3e C) is a key property of a value-based system. Individuals with ventromedial frontal lobe damage have been found to make more transitivity errors in the past, but it is not known whether vmPFC damage causes fundamentally intransitive choices (implying abolishment of value), or transitive but noisier choices (implying preservation of value but increased instability). We found strong evidence for the second case, demonstrating that vmPFC damage adds instability to valuation but does not abolish it. The evidence I present here is consistent with the theory that vmPFC is involved in a subjective value-based process during decision-making, yet that value is a distributed process over many brain regions where other regions may compensate for the loss of the vmPFC in calculating value

    Mathematical Modeling and Fuzzy Adaptive PID Control of Erection Mechanism

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    This paper describes an application of fuzzy adaptive PID controller to erection mechanism. Mathematical model of erection mechanism was derived. Erection mechanism is driven by electro-hydraulic actuator system which is difficult to control due to its nonlinearity and complexity. Therefore fuzzy adaptive PID controller was applied to control the system. Simulation was performed in Simulink software and experiment was accomplished on laboratory equipment. Simulation and experiment results of erection angle controlled by fuzzy logic, PID and fuzzy adaptive PID controllers were respectively obtained. The results show that fuzzy adaptive PID controller can effectively achieve the best performance for erection mechanism in comparison with fuzzy logic and PID controllers

    In-plane vibration modal analysis of heavy-loaded radial tire with a larger flat ratio

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    Experimental modal analysis, dynamic modeling and parameter identification is employed to investigate the in-plane vibration modal characteristic of a heavy-loaded radial tire with a larger flat ratio. In-plane vibration characteristic of heavy-loaded radial tire is modeled as flexible beam on modified elastic foundation model and flexible tread and distributed sidewall are respectively modeled as the Euler beam and distributed mass element with sectional stiffness. Analytic relationship between the modal resonant frequency and the structural parameters is solved and derived with modal expansion method. The in-plane coupling modal between the flexible tread and sidewall is investigated experimentally. The unknown structural parameters are identified by the genetic algorithm based on the experimental and analytical modal parameter. The higher order modal frequency is predicted with the identified structural parameters and the influence of structural parameters on the modal parameters is compared. Experimental and theoretical result shows that: the experimental modal analysis and theoretical modeling method with the coupling feature of flexible tread, distributed sidewall and rim can accurately characterize the in-plane vibration feature of heavy-loaded radial tire within the frequency band of 300 Hz, compared with the method which only considers the flexible feature of tread and is limited to 180 Hz

    Matematičko modeliranje i neizrazito upravljanje mehanizmom za poravnavanje i podizanje

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    The moving process of a leveling and erecting mechanism is complicated, which involves six hydraulic cylinders. The research established mathematical model and optimized the moving process of the leveling and erecting mechanism. Kinematic analysis of the mechanism was accomplished. Mathematical model of the hydraulic system was established. Working scheme was designed consisting of workflow, trajectory planning, leveling strategy and control method. The mechanical, hydraulic and control models were respectively established in Pro/E, ADAMS, AMESim and Simulink software. Co-simulation was carried out to validate the designed scheme. Experiment was completed on a platform. The results of simulation and experiment indicate that the designed scheme is feasible. Fuzzy adaptive PID controller has an excellent effect in controlling the leveling and erecting mechanism.Gibanja mehanizma za poravnavanje i podizanje složeni je proces koji uključuje šest hidrauličkih cilindara. Istraživanje postavlja matematički model i optimizira proces gibanja mehanizma za poravnavanje i podizanje. Provedena je kinematička analiza mehanizma. Postavljen je matematički model hidrauličkog sustava. Radni program načinjen je uključujući tijek rada, planiranje trajektorije, strategiju poravnavanja i metodu upravljanja. Mehanički, hidraulički i upravljački modeli redom su izvedeni u Pro/E, ADAMS, AMESim i Simulink programskim paketima. Provedena je kosimulacija za validaciju načinjenog radnog programa. Eksperiment je proveden na stvarnoj platformi. Rezultati simulacije i eksperimenta ukazuju na izvedivost predloženog radnog programa. Neizraziti adaptivni PID regulator daje odličan efekt pri upravljanju mehanizma za poravnavanje i podizanje

    Bis[hexa­amminecobalt(III)] penta­chloride nitrate

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    The title compound, [Co(NH3)6]2Cl5(NO3), was obtained under hydro­thermal conditions. The asymmetric unit contains three Co3+ ions, one lying on an inversion center and the other two located at 2/m positions. All Co3+ ions are six-coordinated by NH3 mol­ecules, forming [Co(NH3)6]3+ octahedra, with Co—N distances in the range 1.945 (4)–1.967 (3) Å. The nitrate N atom and one of the O atoms lie at a mirror plane. Among the Cl− anions, one lies in a general position, one on a twofold axis and two on a mirror plane. N—H⋯O and N—H⋯Cl hydrogen bonds link the cations and anions into a three-dimensional network

    Co-simulation and Experiment Research on a Novel Erection Mechanism

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    The erection mechanism with movable back hinged bearing is a novel erection mechanism and the form of its moving process is complicated. The novel erection mechanism needs to be extensively tested to prove its value and to ensure it works properly. Kinetic analysis was accomplished and mathematical model of the hydraulic system was acquired. Fuzzy adaptive PID control was adopted for the erection mechanism taking advantage of fuzzy control and PID control. The novel erection mechanism was validated by virtual prototype technology realized by co-simulation method. The mechanical, hydraulic and control models were respectively established in ADAMS, AMESim and Simulink. Experiment was completed on a platform. The results of simulation and experiment indicate that the novel erection mechanism can move based on designed scheme and the control effect of fuzzy adaptive PID control is excellent. The novel erection mechanism has great practical value

    In-plane vibration analysis of heavy-loaded radial tire utilizing the rigid-elastic coupling tire model with normal damping

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    Theoretical modeling, parameters identification and vibration characteristic of heavy-loaded radial tire is investigated with rigid-elastic coupling model with normal damping. The normal damping, including structural damping of flexible carcass and proportion damping of distributed sidewall element is added to enrich the flexible beam on modified elastic foundation tire model. The rigid-elastic coupling tire model with normal damping is investigated and derived with finite difference method. The mass, stiffness and damping matrixes of the proposed tire model are analytically related with the structural and geometrical parameters of heavy-loaded radial tire. Taking the error between the analytical and experimental transfer function as the object value, Genetic Algorithm (GA) is utilized to identify the damping coefficients of flexible carcass and distributed sidewall element. The influence of modal order and tire damping parameters on the in-plane transfer function is discussed. The theoretical and experimental results show that the rigid-elastic coupling tire model with normal damping can achieve the sectional feature of in-plane transfer function resulting from the coupling characteristic between the flexible carcass and distributed sidewall element within the frequency band of 300 Hz

    catena-Poly[[[triaqua­copper(II)]-μ-2,2′-bipyridine-3,3′-dicarboxyl­ato-κ3 N,N′:O] monohydrate]

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    The title compound, {[Cu(C12H6N2O4)(H2O)3]·H2O}n, was synthesized under hydro­thermal conditions. The Cu2+ ion is six-coordinated by three water O atoms, and two N atoms and one O atom of the 2,2′-bipyridine-3,3′-dicarboxyl­ate bridging ligand in a sligthly distorted octa­hedral environment. The 2,2-bipyridine-3,3′-dicarboxyl­ate bridges link the Cu2+ ions into chains along the b-axis direction. These chains are further linked by O—H⋯O hydrogen bonds involving the water solvent mol­ecules, forming a three-dimensional framework
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