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Formation control finds broad applications in numerous fields, such as cooperative detection, surveillance, transportation, and disaster rescue. In this article, aiming at hunting a moving target, a two-stage surrounding control algorithm is proposed for linear multiagent systems subject to input saturations. An adaptive distributed observer is developed for each agent to reconstruct the target's position. With the assistance of the algebraic graph theory and low gain feedback technique, distributed controllers are designed to drive the agents to encircle the moving target with a fixed radius and evenly distributed phase angles. Finally, both numerical simulations and experiments are conducted to verify the effectiveness of the proposed control algorithm.

This paper considers the output feedback stabilization problem of linear systems with infinite distributed delays in their inputs and outputs. A low gain observer is proposed to estimate the state of the concerned system with infinite distributed delays in its inputs and outputs. The observer based output feedback controller is then developed. It is shown that the resulting closed loop system is globally asymptotically stable. It should be pointed out that the output feedback control problem of linear systems with infinite distributed input and output delays is first time investigated to the best of our knowledge. Finally, some numerical examples are presented to demonstrate the effectiveness of the proposed controller.

Aim: Microstrip patch antennas are rapidly used in the areas of wireless systems due to its low cost and lightweight. But still it has research issues like narrow bandwidth, poor efficiency, and low gain. The objective of this study is to enhance the gain of Novel DB-RPA antenna. This work presents the comparative analysis of gain enhancement between rectangular and circular patch antennas. Materials & Methods: Dual band rectangular patch antenna (DB-RPA) and circular patch antenna (CPA) are designed to enhance the gain of the antenna by using HFSS software and by collecting the dataset of 40 samples with pretest power of 80%. The gain of CPA is 1.89 dB and DB-RPA is 4.66 dB. The directivity of CPA is 3.52 dB and DB-RPA is 4.89 dB. Results: On performing an independent sample t-test on the two groups considered, it appears that the mean gain of Novel DB-RPA is 3.0755 and CPA is 0.8820 with significance value of 0.001 (p

The paper presents a novel method for the improvement in the bandwidths by mode merging of the circularly polarized dielectric resonator antenna (CPDRA). The results of improved axial-ratio bandwidth and impedance bandwidth is compared with the previous work. In this design, 50 $$\Omega$$ terminator diverts current in such a way that adjacent exited modes get merged. Also the upper order modes are merged to the lower order modes and a significant enhancement is achieved in overlapping bandwidth. The proposed CPDRA provides axial ratio bandwidth of 53.78% (axial ratio

Under what conditions do humans systematically deviate from rational decision making? Here we show that pupillary indices of low neural gain are associated with strong and consistent biases across six different extensively-studied decision making tasks, whereas indices of high gain are associated with weak or absent biases. Lower susceptibility to biases, however, comes at the cost of indecisiveness, or alternatively, prolonged deliberation time. We explain the association between low gain and strong biases as reflecting a broader information integration process that gives greater weight to weak biasing influences. The findings underscore the role of pupil-linked brain states in the generation of decision making biases.Significance“Framing effects” are demonstrations that people’s decisions can be biased by the way a decision problem is presented, and consequently, people can make decisions that violate the principles of rationality. Using a set of classic decision-making tasks, we show that pupil dilation, previously linked to levels of the neuromodulator norepinephrine and to a tradeoff between narrowly focused and broadly integrative modes of information processing, distinguishes between people who are consistently biased and people who are relatively immune to these effects. Our findings suggest that norepinephrine may drive these individual differences, and that a narrowly focused mode of information processing confers relative immunity to these decision making biases, whereas the integration of a wider range of information results in greater susceptibility.

Ultra-wideband (UWB) phased array antennas are essential for radar, communication, and Electronic Warfare (EW) applications. Systems can operate over wide-band coverage. The high gain systems require wide-band, wide-angle scanning, good radiation pattern, and return loss over a multi-octave bandwidth. This review discusses the problems present in the UWB phased array system, which include mutual coupling, grating lobe rejection, active return loss, gain fluctuation with scanning, and multiple beam generation. In this, the aperture size of the array is limited by the overall gain requirement of the system. On the other hand, low gain systems require a wide-band with a good radiation pattern and axial ratio. Here the matching over wide-band is simpler as it depends on broadband balun configuration. This system has limited bandwidth over scan angles. These antennas are more preferred as wearable antennas in communication applications. This paper mainly discusses the existing UWB phased array antennas such as Vivaldi Arrays, All-metal Arrays, Spiral Arrays, Sinuous Arrays, and Coupled Arrays. This review paper presents a correct direction for selecting the type of antenna in terms of impedance bandwidth, gain, and materials influencing antenna performance, suited for different applications.

This paper investigates the output consensus problem of networked heterogeneous linear multi-agent systems. All systems have heterogeneous multi-input multi-output (MIMO) linear dynamics, and the r...

In this paper we study the distributed leader state estimation problem in leader-follower multi-agent systems over a deterministic network and under time-varying communication delays. In this work we propose a distributed estimation technique that allows the follower agents to collectively reconstruct the leader agent states by communicating their estimates with neighboring agents. Additionally, we assume that the communications between the leader and followers are subject to heterogeneous time-varying delays. By using the low gain methodology, sufficient stability conditions of the estimation error dynamics in the presence of network latency are derived, including an upper bound for the delay magnitude. Lastly, the proposed distributed state estimation method is applied to develop a solution to the leader tracking problem in leader-follower multi-agent systems. An illustrative example is also presented to verify the effectiveness of our theoretical results.

Dendrites are important determinants of the input-output relationship of single neurons, but their role in network computations is not well understood. Here, we used a combination of dendritic patch-clamp recordings and in silico modeling to determine how dendrites of parvalbumin (PV)-expressing basket cells contribute to network oscillations in the gamma frequency band. Simultaneous soma-dendrite recordings from PV basket cells in the dentate gyrus revealed that the slope, or gain, of the dendritic input-output relationship is exceptionally low, thereby reducing the cell’s sensitivity to changes in its input. By simulating gamma oscillations in detailed network models, we demonstrate that the low gain is key to increase spike synchrony in PV neuron assemblies when cells are driven by spatially and temporally heterogeneous synaptic input. These results highlight the role of dendritic computations in synchronized network oscillations.

In order to further improve the output power of W-band traveling wave tube (TWT), a low gain TWT was proposed as a secondary amplifier. It uses a double staggered grating slow wave structure (DSG-S...

The potential of flipped classroom instruction was undertaken to enhance the performance of students in learning electrochemistry. This study was to investigate the effects of the Flipped Classroom Model (FCM) on students’ performance in electrochemistry as well as their general perceptions. The study used a quasi-experimental method that utilized pre-test-post-test nonequivalent groups design. Students’ perception of FCM was based on a questionnaire. Results of the independent t-test noted that there was a significant difference between the two groups (t (26) =-2.281, p-value=0.031). The results suggested that the Flipped Classroom Group and Conventional Classroom Group are incomparable in terms of performance in electrochemistry after the intervention. The experimental group has a medium gain while the control group has a low gain as reflected by the normalized gain (Hake factor) values of 0.45 (SD = 8.32) and 0.22 (SD = 6.48), respectively. This only means that flipped classroom instruction has a generally positive effect on the achievement of students in learning electrochemistry. The students’ perceptions were positive. Students perceived that FCM helped them understand the concepts in electrochemistry easily. They also suggested that FCM was enjoyable, timely, and engaging. Lastly, the majority of the students agreed about the use of Flipped classroom instruction as an effective way to learn electrochemistry.

Integrated or thematic learning of science at the school level must continue to be improved. The purpose of this study was to improve the learning outcomes of science students in themes 6 and 7 on the topic of Biology through the use of video. The research method used in this study was classroom action research with 2 cycles. This research was conducted in January-February 2019 at State Elementary School 02 Jatimulya (SDN Jatimulya 02), Bekasi. The number of samples used was 36 students. Science learning outcomes of Biology topics after being given a learning video experienced an increase, although not large, while a gain score of 0.14 with a low gain score criteria. In conclusion, there was an increase in science learning outcomes on the topic of Biology after being given a learning video.

In this note, we investigate the stabilization of discrete-time linear systems with an unknown time-varying delay. Existing literature on the stabilization of time-delay systems require some knowledge, such as an upper bound, of the delay. In this paper, by proposing a switched low-gain feedback control law, we are able to achieve asymptotic stabilization of the system without any knowledge of the delay. In addition, the proposed switched low-gain feedback law also significantly improves the closed-loop system performance in terms of overshoot and convergence speed in comparison with the traditional fixed gain design. Simulation study illustrates the effectiveness of our theoretical results.

In this work, we present the pLGAD concept, which is based on the LGAD technology developed at IMB-CNM. We describe the main characteristics of this novel detector suitable for low energy particles detection. Using 2D TCAD numerical simulations we optimize its multiplication region characteristics, the V BD -Gain trade-off and the periphery design. Also, we define a first pLGAD fabrication run to integrate it at IMB-CNM clean room. Moreover, we describe the first n-type LGAD prototype.

In this contribution, we will present the status of the technological developments at IMB-CNM to fabricate Inverse Low Gain Avalanche Detectors (iLGAD) for pixelated detectors. This iLGAD sensor concept is one of the most promising technologies for enabling the future 4D tracking paradigm that requires both precise position and timing resolution. In the iLGAD concept, based on the LGAD technology, the readout is done at the ohmic contacts, allowing for a continuous unsegmented multiplication junction. This architecture provides a uniform gain over all the active sensor area. This concept was successfully demonstrated in a first generation of 300 μm thick iLGAD sensors. In the second generation, we have fabricated thick iLGAD sensor optimizing the periphery for X-Ray irradiations. Currently, we are developing a third generation based on 50 μm thick pixelated iLGADs optimized for timing detection, with a periphery design able to sustain high electric fields and a simpler single-side manufacturing process.

This paper aims to give an overview of the current status of this technology. The most interesting approaches for future 4-dimensional tracking applications based on the LGAD technology will be presented here. In addition, the latest results on the performance after irradiation of standard LGADs will be reviewed too.

This paper presents 1.713.5 GHz dual-band concurrent LNA with small gain deviation and low NF. Proposed LNA incorporates mutual induction matching circuit and notch filter matching circuit on input and output side to improve gain deviation. Also, a part of the primary inductor of the input matching circuit adopts an external inductor to improve NF. The measured Sii, S22, S 21 and NF were -6.44,-15.7,10.9, and 2.67 dB at 1.7 GHz and -7.65, -6.05,10.2 and 2.02 (4.0 GHz) dB at 3.5 GHz, respectively. The power consumption is 14.0 mW from a 1.8 V supply voltage. The proposed LNA is designed and fabricated by using the TSMC-180 nm CMOS process. The concurrent LNA in this study gives the lowest NF in our knowledge.

Based on the predictor feedback law for the stabilization of discrete-time systems with delay, as introduced in Sect. 1.5, we develop a truncated predictor feedback (TPF) law that simplifies the implementation of its predictor feedback prototype. An eigenstructure assignment based low gain design as well as an alternative Lyapunov equation based design are employed to parameterize the feedback gain matrix of the TPF law in a low gain parameter. The core of low gain feedback designs is that a sufficiently small low gain parameter would compensate an arbitrarily large delay in a discrete-time linear system without exponentially unstable open loop poles.

Low gain feedback designs, such as the eigenstructure assignment based design and the Lyapunov equation based design, are essential elements of TPF designs. TPF laws whose feedback gain matrices are parameterized in a feedback parameter compensate an arbitrarily large delay in linear systems that are not exponentially unstable. Given any amount of delay, stabilization is achieved as long as the feedback parameter is sufficiently small. As manifested in Chaps. 2 and 3, such a low gain nature of the TPF laws, of both state feedback and output feedback types, is the core of their stabilizing ability.

A difficulty arises in the implementation of a predictor feedback law with the distributed delay term in it. To overcome this implementation difficulty, Lin and Fang (IEEE Trans. Autom. Control 52(6), 998–1013 (2007)) proposed to truncate the distributed delay term from the predictor feedback law, implementing only the remaining static state feedback term. This leads to a truncated predictor feedback (TPF) law, which can be readily implemented. In this chapter, we introduce the intuition, expression, and construction of the TPF law and its output feedback counterpart. In particular, the construction of the feedback gain matrix of the truncated predictor feedback law is first carried out by using an eigenstructure assignment based low gain feedback design technique. An alternative design is then presented by using the Lyapunov equation based low gain design technique. Stabilization of linear systems with input delay by the TPF is established under both the eigenstructure assignment based TPF and the Lyapunov equation based TPF.

The Compact Muon Solenoid (CMS) experiment at the CERN Large Hadron Collider (LHC) is undergoing an upgrade program to prepare for the upcoming High-Luminosity era of the LHC. The design of a new timing layer used to measure minimum ionizing particles (MIPs) with a time resolution of (~) 30 ps) and coverage up to pseudo-rapidity |η| = 3.0 is presented. The MIP timing detector (MTD) will be composed of a central barrel region instrumented with LYSO:Ce crystals, and two end-caps instrumented with radiation tolerant low gain avalanche detectors (LGADs). The precision timing information from the MTD will be used to reduce the effects of high pileup on object reconstruction.

As a panchromatic band, the Day-Night Band (DNB) on National Oceanic Atmospheric Administration (NOAA)-20 Visible Infrared Imaging Radiometer Suite (VIIRS) has a unique capability of observing very low radiances down to Nano-watt [cm−1 sr−1] level, because of its three different focal planes with gain stages. The DNB radiometric calibration is based on the Solar Diffuser observations near the night to day time termination points. Besides the primary calibration source of SD, the moon provides alternative source of calibration with a specific lunar roll maneuvers. This study provides detailed methodology and results of lunar calibration for NOAA-20 VIIRS sensor and initial two year DNB radiometric calibration results from SD and scheduled lunar calibration. Over two years of NOAA-20 VIIRS operation, the Low Gain Stage (LGS) slope (inverse gain) trend showed a decreasing trend, whereas the calculated monthly lunar F-factor showed a stable response (inverse gain normalized to the lunar irradiance model) using a lunar irradiance model. These differences are monitored, compared, and applied for the best quality of NOAA-20 VIIRS DNB product.

We aim to introduce and demonstrate several improvements that are applied to the on-orbit solar diffuser (SD) calibration of the day-night band (DNB) low gain stage (LGS) of the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the NOAA-20 satellite. The most important improvement is the expansion of the angular range, referred to “sweet spot”, from 4° to 7.8° in order to increase the number of fully-illuminated scans considered for the SD calculation. The increase in scan number enables the completion of on-orbit calibration using the SD within one orbit, compared with the multiple orbits approach, which is required in the current standard approach applied in operational DNB LGS calibration coefficients look-up tables (LUTs) updates. The NOAA-20 DNB LGS calibration coefficients have been derived with the new methodology and the results show a more stable, smoother, and less noisy trend when compared with the current standard approach. The results also demonstrate that the NOAA-20 VIIRS DNB overall on-orbit performance has been very stable.

Strip helix antennas offer better performance at wide bandwidth and more compact in size than conventional helix antennas. However, strip helix antennas have a relatively low gain compared to conventional helix antennas. In this paper, a strip helix antenna with 2.4 GHz frequency was designed, simulated, fabricated, and measured. This strip helix antenna was added with several parasitic rings, and its ground plane size was reduced to increase the gain value and its performance. The best simulation results according to the desired parameters were with return loss < -10 dB of -10.366 dB, VSWR < 2 of 1.8702, and directional radiation pattern of 66.5° beamwidth angle. However, the gain did not match with the desired parameters > 12 dB with the result of 8.9612 dB. Measured results showed that the helix strip antenna has a return loss of -10.37 dB and VSWR of 1.870. The parasitic rings addition can increase the strip helix antenna gain of 0.0201 dB and improves performances of return loss, VSWR, and bandwidth. Despite that, the ground plane size reduction actually decreases the gain value.

The narrow bandwidth and low gain performances of a reflectarray are generally improved at the cost of high design complexity, which is not a good sign for high-frequency operation. A dual resonance asymmetric patch reflectarray antenna with a single layer is proposed in this work for 5G communication at 26 GHz. The asymmetric patch is developed from a square patch by tilting its one vertical side by a carefully optimized inclination angle. A progressive phase range of 650&deg, is acquired by embedding a circular ring slot in the ground plane of the proposed element for gain improvement. A 332-element, center feed reflectarray is designed and tested, where its high cross polarization is suppressed by mirroring the orientation of asymmetric patches on its surface. The asymmetric patch reflectarray offers a 3 dB gain bandwidth of 3 GHz, which is 4.6% wider than the square patch reflectarray. A maximum measured gain of 24.4 dB has been achieved with an additional feature of dual linear polarization. Simple design with wide bandwidth and high-gain of asymmetric patch reflectarray make it suitable to be used in 5G communications at high frequencies.

International audience; This paper gives details about simulation and measurement calculations of total scanning power and coverage efficiency parameters. The coverage efficiency CDFs matches numerical output very well with the measured one at high gain. Although the uncertainties of fabrication and measurement processes make quite a big different at lower gain, the matched angle accounts for most of the radiated power.

A design of an elliptical patch antenna array for circular polarization is presented. Single patch elliptical microstrip antenna has low gain which is improved by the use of single feed elliptical patch antenna array. The antenna array is designed at 2.8 GHz. It shows a gain of 9.825dB and axial ratio 2.045dB.

This paper investigates the stabilization problem of linear systems with distributed infinite input delays. By introducing a stability result on systems with infinite delays, it is shown that a stabilizable linear system with distributed infinite input delays can be globally asymptotically stabilized with low gain controllers as long as the open-loop system is not exponentially unstable. Our result includes constant delay and bounded distributed delay as its special cases. It should be noted that the stabilization problem of systems with distributed infinite input delays, to our best knowledge, has not been considered in existing literatures. Simulation examples are provided to illustrate the effectiveness of our theoretical results.

In this paper, the consensus problem of high-order multi-agent systems with inherent feed-forward delayed non-linear dynamics is investigated. First, a new kind of aperiodically intermittent communication strategy, which can be regarded as an extension of continuous communication, is proposed. The time-varying delay is considered in the multi-agent systems and the delay is not restricted to less than the communication width. Moreover, in order to reach a consensus, the effect of the feed-forward non-linearity and the time-varying delay is eliminated by designing a low-gain control protocol. Based on Lyapunov stability theory, graph theory and inequality techniques, some sufficient conditions related to the input gain and the communication width are obtained for achieving the consensus. Finally, a simulation example is presented to demonstrate the effectiveness of the proposed method.

The coverage control problem for mobile sensor networks with limited communication ranges is addressed in this paper. The goal of the problem is to minimize a coverage cost function which indicates the largest arrival time from the mobile sensor network to the points on a circle. Different input constraints are imposed on the sensors with first-order dynamics due to their different movement capabilities. To deal with this problem, low gain feedback is utilized to develop a distributed coverage control law for each sensor and an upper bound on the low gain is also provided. It is shown that networked mobile sensors can be driven to the configuration minimizing the coverage cost function as long as their communication ranges exceed a threshold and network connectivity of the sensors does not need to be preserved during the coverage task. Finally, a numerical example is given to illustrate the effectiveness of the proposed coverage control law.

This paper represents the clinical decision support system for video head impulse test (vHIT) based on fuzzy inference system. It examines the eye and head movement recorded by the eye movement tracking device, calculates the vestibulo-ocular reflex (VOR) gain, and applies fuzzy inference system to output the normality and artifact index of the test result. The position VOR gain and the proportion of covert and overt catch-up saccades (CUS) within the dataset are used as the input of the inference system. In addition, this system yields one more factor, the artifact index, which represents the current interference in the dataset. Data of fifteen vestibular neuritis patients and two of normal subjects were evaluated. The artifact index appears to be very high in the lesion side of vestibular neuritis (VN) patients, indicating highly theoretical contradictions, which are low gain but without CUS, or normal gain with the appearance of CUS. Both intact side and normal subject show high normality and low artifact index, even though the intact side has slightly lower normality and higher artifact index. In conclusion, this is a robust system, which is the first one that takes gain and CUS into account, to output not only the normality of the vHIT dataset, but also the artifacts.

Low Gain Avalanche Detectors (LGAD) are silicon particle sensors with intrinsic gain through a thin p-type multiplication layer inserted between n-type implant and p-type bulk. The first prototype of LGAD sensors in China have been developed at the Institute of High Energy Physics (IHEP) of Chinese Academic Sciences and the Novel Device Laboratory (NDL) of Beijing Normal University. With an active thickness of 33 μ m, good breakdown performance, gain > 10, these sensors have reached jitter contribution of 10 ps to timing resolution with laser tests.