Positive position feedback is an attractive control law for the control of plants having no high frequency roll-off. The tuning of the parameters of the positive position feedback to obtain the ...desired closed-loop performance is quite challenging. This paper presents a technique to design the positive position feedback controller with the optimal damping. The technique is demonstrated on a single degree-of-freedom system. The poles of the positive position feedback are tuned using the method of maximum damping, which states that the maximum damping is achieved when both closed-loop poles of the system are merged. The parameters of the positive position feedback are dependent on the desired target damping in the closed-loop system. However, arbitrary choice of target damping results in high response at the frequencies lower than the tuning frequency. The optimal value of the target damping is obtained by minimizing the
H
2
norm of the closed-loop transfer function of the system. The influence of the various parameters of the positive position feedback on the closed-loop response of the system is also studied. Finally, the experiments are conducted to verify the effectiveness of the proposed technique.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
Electric vehicles are beneficial to the environment owing to its nonproduction of emissions and excessive noise; however, they have their own limitations with respect to charging difficulties and ...mileage anxiety. In order to address these problems, dynamic wireless power transfer (DWPT) technology has been developed. In this article, we replace a conventional open-loop method without dc-dc converter with the proposed dc-dc converter in the energy receiver in order to improve output power. Moreover, to make sure that the DWPT system is reliable when the coupling coefficient changes rapidly over a wide range of values, we propose model predictive control (MPC) to ensure optimal dynamic-tracking performance. Considering the fact that sampling delay will cause an error in the controller output, the system is modeled accurately in order to improve the MPC performance. In addition, the MPC and double closed-loop proportional-integral-differential control are compared with simulations and experiments, the results of which demonstrate the effectiveness of MPC-based DWPT.
•We firstly use a 5-dimensional conservative hyper-chaotic system to generate key streams for image encryption.•Compare to dissipative chaotic system, the conservative hyper-chaotic system we used ...has no attractor, thus can avoid the reconstructing attacks.•We propose a closed-loop diffusion mechanism between blocks dependent on both plaintext and ciphertext (CDMBDPC) for the first time. Different to the existing open-loop diffusion scheme, our closed-loop diffusion scheme can greatly improve the reliability of encryption system. In addition, our closed-loop diffusion mechanism implements the complete diffusion process of encrypting the first plaintext pixel block to encrypting the last pixel block and then updating the first ciphertext block.•To resist reconfiguration attack and statistical attack, the chaotic system used to generate pseudorandom sequences can't be refactored and key streams of an encryption model need to be random. Using the 5d conservative hyperchaotic system, we design a new chaos-based encryption algorithm with random key streams, and a closed-loop diffusion mechanism is designed in the encryption model to enhance the encryption reliability.•The image encryption scheme is sensitive to both the plain image and the cipher image.•The experimental results show that the proposed encryption algorithm has excellent security and reliability compared with exiting algorithms.
Dissipative chaotic systems have been widely used in digital image encryption schemes in the past 20 years. However, compared to conservative chaotic systems, the dissipative chaotic systems have attractors thus attacker can reconstruct the chaotic systems by reconstructing the attractors. Therefore, the conservative chaotic systems are more suitable in chaos-based encryption system because they have no attractors thus can avoid the reconstructing attacks. Based on this, an image encryption scheme based on conservative hyper-chaotic system and closed-loop diffusion between blocks is proposed in this paper. On the one hand, the conservative hyperchaotic system has strong pseudo-randomness and anti-reconstruction attack property. On the other hand, different from the existing closed-loop diffusion schemes which change pixel values one by one until the last pixel value is changed, the proposed closed-loop diffusion method cannot only generate the first ciphertext and other ciphertext blocks but also update the first ciphertext block using the other generated ciphertext block information. In addition, the key streams are related to plaintext and ciphertext. Consequently, the key, plaintext and ciphertext form an organic whole to ensure the sensitivity of the encryption system. Moreover, simulation results and analysis show that the encryption scheme has strong security and excellent performance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We introduce a remote interface to control and optimize the experimental production of Bose–Einstein condensates (BECs) and find improved solutions using two distinct implementations. First, a team ...of theoreticians used a remote version of their dressed chopped random basis optimization algorithm (RedCRAB), and second, a gamified interface allowed 600 citizen scientists from around the world to participate in real-time optimization. Quantitative studies of player search behavior demonstrated that they collectively engage in a combination of local and global searches. This form of multiagent adaptive search prevents premature convergence by the explorative behavior of low-performing players while high-performing players locally refine their solutions. In addition, many successful citizen science games have relied on a problem representation that directly engaged the visual or experiential intuition of the players. Here we demonstrate that citizen scientists can also be successful in an entirely abstract problem visualization. This is encouraging because a much wider range of challenges could potentially be opened to gamification in the future.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Summary
Objective
Evaluate the seizure‐reduction response and safety of mesial temporal lobe (MTL) brain‐responsive stimulation in adults with medically intractable partial‐onset seizures of mesial ...temporal lobe origin.
Methods
Subjects with mesial temporal lobe epilepsy (MTLE) were identified from prospective clinical trials of a brain‐responsive neurostimulator (RNS System, NeuroPace). The seizure reduction over years 2–6 postimplantation was calculated by assessing the seizure frequency compared to a preimplantation baseline. Safety was assessed based on reported adverse events.
Results
There were 111 subjects with MTLE; 72% of subjects had bilateral MTL onsets and 28% had unilateral onsets. Subjects had one to four leads placed; only two leads could be connected to the device. Seventy‐six subjects had depth leads only, 29 had both depth and strip leads, and 6 had only strip leads. The mean follow‐up was 6.1 ± (standard deviation) 2.2 years. The median percent seizure reduction was 70% (last observation carried forward). Twenty‐nine percent of subjects experienced at least one seizure‐free period of 6 months or longer, and 15% experienced at least one seizure‐free period of 1 year or longer. There was no difference in seizure reduction in subjects with and without mesial temporal sclerosis (MTS), bilateral MTL onsets, prior resection, prior intracranial monitoring, and prior vagus nerve stimulation. In addition, seizure reduction was not dependent on the location of depth leads relative to the hippocampus. The most frequent serious device‐related adverse event was soft tissue implant‐site infection (overall rate, including events categorized as device‐related, uncertain, or not device‐related: 0.03 per implant year, which is not greater than with other neurostimulation devices).
Significance
Brain‐responsive stimulation represents a safe and effective treatment option for patients with medically intractable epilepsy, including patients with unilateral or bilateral MTLE who are not candidates for temporal lobectomy or who have failed a prior MTL resection.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Using a closed-loop system significantly improves time in range (TIR) 70-180 mg/dL in patients with type 1 diabetes (T1D). In a 6-month RCT, 112 subjects were randomly assigned to closed-loop control ...(Tandem Control-IQ) after obtaining 2 weeks of baseline Continuous glucose monitoring (CGM) data from sensor-augmented pump therapy. We compared glycemic outcomes from baseline to end of study among subgroups classified by baseline HbA1c levels. All HbA1c subgroups showed an improvement in TIR due to reduction of both hyperglycemia and hypoglycemia. Those with HbA1c <6.5% improved mostly by reducing nocturnal hypoglycemia due to the automated basal insulin adjustments. Those with HbA1c ≥8.5% improved mostly by reducing daytime and nocturnal hyperglycemia due to both automated basal insulin adjustments and correction boluses during the day. There does not appear to be any reason to exclude individuals with T1D from automated insulin delivery based on their HbA1c. Clinical Trial Identifier: NCT03563313.
Resonant fiber optic gyro (RFOG) is a type of inertial sensor with great application potential. Its closed-loop signal detection methods include single closed-loop, double closed-loop and other ...methods to ensure high system stability and high-precision signal output. In view of the respective advantages of single and double closed-loop systems, a single-double interval closed-loop scheme for RFOG is proposed in this letter. By introducing the threshold trigger mechanism, the advantages of low control signal noise of the single closed-loop system and large dynamic range of the double closed-loop system are fully combined. In addition, in order to improve the linearity of the demodulation curve, a linear fitting method is applied to the system. The experiment shows that the short-term and long-term stability of the system have been improved effectively.
Closed-loop chemical recycling provides a solution to the end-of-use problem of synthetic polymers. However, it remains a major challenge to design dynamic bonds, capable of effective bonding and ...reversible cleaving, for preparing chemically recyclable cross-linked polymers. Herein, we report a dynamic maleic acid tertiary amide bond based upon reversible amidation reaction between maleic anhydrides and secondary amines. This dynamic bond allows for the construction of polymer networks with tailorable and robust mechanical properties, covering strong elastomers with a tensile strength of 22.3 MPa and rigid plastics with a yield strength of 38.3 MPa. Impressively, these robust polymeric materials can be completely depolymerized in an acidic aqueous solution at ambient temperature, leading to efficient monomer recovery with >94% separation yields. Meanwhile, the recovered monomers can be used to remanufacture cross-linked polymeric materials without losing their original mechanical performance. This work unveils a general approach to design polymer networks with tunable mechanical performance and closed-loop recyclability, which will open a new avenue for sustainable polymeric materials.
The paper presents a solution to the problem of synthesis of control with respect to the sliding interval length for the optimization of a class of discrete linear multidimensional objects with a ...quadratic performance criterion. The equation of motion of a closed multidimensional discrete system in the general non-stationary case is derived based on the length of the optimization interval and their main properties. The closed-loop is fitted with a signal representing the predicted values averaged over the whole sliding interval of optimization with a certain weight. A problem with a sliding optimization interval may not require a real-time solution by means of a sequence of solutions on compressed intervals. Therefore, the study of control systems with optimization on a sliding interval is of undoubted interest for a number of practically important control problems.
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