Synchronization Mechanism Research Articles

Synchronization and vibration absorption analysis of a dual-body vibrating screen driven by multiple motors with double-frequency actuation

Vibrating screen is the pivotal equipment of solid control in drilling mud purification system. With the continuous upgrading of rapid drilling technology, the conventional single-body vibrating screen with the same-frequency excitation is difficult to satisfy the needs of current drilling operations. Therefore, a newly dual-body vibration absorption system model with double-frequency excitation is proposed to improve the mechanical performance of screening equipment. To grasp the dynamic characteristics of the vibration system, the synchronization mechanism and stability criterion are theoretically studied by modified small parameter average method and Poincare-Lyapunov method. Meanwhile, the vibration absorption ability, coupling torque and synchronization state of the system are numerically discussed. Lastly, the electromechanical coupling model of system is established by Runge-Kutta method to verify the reliability of theoretical analysis and numerical calculation. According to the results of research, the synchronous characteristics are mainly determined by the installation position of motors and the mass ratio of eccentric rotors. Besides, the synchronization ability between identical-frequency motors is stronger than different frequency motors. The present work can provide theoretical direction for designing of new screening equipment.

Mechanism of Arcuate Kisspeptin Neuron Synchronization in Acute Brain Slices From Female Mice.

The mechanism by which arcuate kisspeptin (ARNKISS) neurons co-expressing glutamate, neurokinin B, and dynorphin intermittently synchronize their activity to drive pulsatile hormone secretion remains unclear in females. In order to study spontaneous synchronization within the ARNKISS neuron network, acute brain slices were prepared from adult female Kiss1-GCaMP6 mice. Analysis of both spontaneous synchronizations and those driven by high frequency stimulation of individual ARNKISS neurons revealed that the network exhibits semi-random emergent excitation dependent upon glutamate signaling through AMPA receptors. No role for NMDA receptors was identified. In contrast to male mice, ongoing tachykinin receptor tone within the slice operated to promote spontaneous synchronizations in females. As previously observed in males, we found that ongoing dynorphin transmission in the slice did not contribute to synchronization events. These observations indicate that a very similar AMPA receptor-dependent mechanism underlies ARNKISS neuron synchronizations in the female mouse supporting the "glutamate two-transition" model for kisspeptin neuron synchronization. However, a potentially important sex difference appears to exist with a more prominent facilitatory role for tachykinin transmission in the female.

Simultaneous removal of cadmium(II) and arsenic(III) from aqueous solutions using pyrite-modified biochar: Effects and mechanisms

Simultaneous removal of cadmium [Cd(II)] and arsenic [As(III)] from aqueous systems is still a great challenge. Through mechanical ball milling and thermal activation, pyrite-modified biochar (PMB) was successfully prepared and used to evaluate its synchronous removal effect and mechanism of Cd(II) and As(III) from aqueous solutions. PMB exhibited a maximum adsorption capacity of 51.0 mg·g−1 for Cd(II) (pH=6) and 65.9 mg·g−1 for As(III) (pH=4) at 25 °C, surpassing that of biochar by 1.5 and 5.7 times, respectively. Interestingly, in the mixed Cd-As system, the presence of Cd(II) hindered the adsorption of As(III) onto PMB, while the presence of As(III) enhanced the adsorption of Cd(II). Additionally, the removal of Cd(II) and As(III) by PMB remained in the range of 70%− 80% under the competition of cations (K+, Mg2+) and anions (NO3-, SO42-), except for the severe inhibition of Cd(II) and As(III) removal by Ca2+ and PO43- due to their specific physicochemical properties. The adsorption of Cd(II) by PMB followed the Langmuir and pseudo-second-order models, involving ion exchange (formation of CdS) and complexation as the main removal mechanisms. And the adsorption of As(III) followed the Freundlich and pseudo-second-order models, involving oxidation of As(III) to arsenic(V) and further complexation as the primary removal mechanisms. After four adsorption-desorption cycles, the adsorption performance of PMB for Cd(II) and As(III) could still reach 78% and 68% of the initial performance. Overall, the results demonstrated that PMB was the preferred eco-friendly material for efficiently removing Cd(II) and As(III) from co-pollution aqueous solutions.

A new fuzzy decoupled sliding mode control of flexible joint robotic manipulators based on the finite‐time observer in the presence of chaos with experimental validation

AbstractThis paper presents a new fuzzy non‐singular fast terminal decoupled sliding mode control based on the finite‐time extended state observer for trajectory tracking control of flexible joint robot manipulators under chaos and uncertainty. First, a suitable chaotic reference is used in a synchronization mechanism to create chaos in the dynamics. Then, the essential modifications made to the conventional decoupled sliding mode control are introduced. A new coupling variable and a non‐singular fast terminal sliding surface are proposed in combination with an extended state observer. A complete convergence analysis is also performed for all the sliding surfaces. Furthermore, two fuzzy systems are designed in such a way that not only they can eliminate the chattering phenomenon but can also improve the convergence time without increasing the control input in a voltage‐based manner. The mathematical proof guarantees the finite‐time asymptotic stability of the closed‐loop control system under the proposed scheme for a class of under‐actuated systems in the presence of structured and un‐structured uncertainties. Finally, some simulations and experimental implementations as hardware‐in‐the‐loop are performed to evaluate the proposed method's performance. The proposed controller is an effective method, as confirmed by the numerical simulation results and experimental validation.

The mechanism of the oxidation of narceine by means of selenous acid -sulphuric acid

The chemistry of selenous acid was misunderstood for many years, being explained by electron back donation. In this communication we disclose the reaction mechanism of the interaction of narceine with selenous acid in sulphuric acid. Narceine is a complex molecule that displays a carboxylic acid, a tertiary amine, a ketone, three methoxy groups and a benzodioxole; so, it was necessary select the principal reaction site. Although a methoxy group can be demethylated with the employed reagent since codeine gives the same violet colour obtained with morphine. The chemical deportment of the methylenedioxy ring in the presence of methoxy groups needed revision. It was found that the five-member ring is cleaved preferentially. Thus, a sustained reaction mechanism could be advanced. The reactive species is protonated selenous acid, which reacts with an oxygen of the cyclic group, water being eliminated. The oxonium ion is neutralized by ring opening in a concerted mechanism involving water reaction at the methylene. An organometallic intermediate is obtained, a selenite, and a hemiacetal. Finally, protonation of the selenium-oxygen double bond produces an acidolysis via a synchronous mechanism involving five electron shifts. This way selenium (II) hydroxide, an ortho-quinone and formaldehyde are obtained.

Energy dissipation mechanism and ballistic characteristic optimization in foam sandwich panels against spherical projectile impact

This study systematically examines the energy dissipation mechanisms and ballistic characteristics of foam sandwich panels (FSP) under high-velocity impact using the explicit non-linear finite element method. Based on the geometric topology of the FSP system, three FSP configurations with the same areal density are derived, namely multi-layer, gradient core and asymmetric face sheet, and three key structural parameters are identified: core thickness (tc), face sheet thickness (tf) and overlap face/core number (no). The ballistic performance of the FSP system is comprehensively evaluated in terms of the ballistic limit velocity (BLV), deformation modes, energy dissipation mechanism, and specific penetration energy (SPE). The results show that the FSP system exhibits a significant configuration dependence, whose ballistic performance ranking is: asymmetric face sheet > gradient core > multi-layer. The mass distribution of the top and bottom face sheets plays a critical role in the ballistic resistance of the FSP system. Both BLV and SPE increase with tf, while the raising tc or no leads to an increase in BLV but a decrease in SPE. Further, a face-core synchronous enhancement mechanism is discovered by the energy dissipation analysis, based on which the ballistic optimization procedure is also conducted and a design chart is established. This study shed light on the anti-penetration mechanism of the FSP system and might provide a theoretical basis for its engineering application.

Features of Application of the Optimized Physical Rehabilitation Program in Patients with Coronary Heart Disease

Multisymptomatic coronary heart disease (CHD) remains a leading problem in cardiology. A person’s ability to perform physical work determines their quality of life, especially in patients with existing symptoms of damage to the cardiovascular system. The most advanced approach in the physical rehabilitation of patients with CHD is the use of ergometric testing indicators.
 The aim. To study the influence of the developed method of cycling training on the indicators of cardiopulmonary exercise (CPX) in patients with CHD.
 Materials and methods. We examined 65 men with CHD, I-II functional class stable angina pectoris, mean age 44.6 ± 1.39 years (from 32 to 60 years). The diagnosis was made on the basis of clinical findings, electrocardiography and laboratory examination according to the generally accepted criteria of the European Society of Cardiology.
 Results. The treatment results were evaluated two weeks after the completion of the physical rehabilitation program. Qualitative assessment was performed by using the CPX test with the recording of cardiac bioelectric potentials from 12 leads. The criteria for discontinuation of the test were generally accepted provisions based on WHO recommendations.
 While developing a physical rehabilitation program and predicting the timing of a functional recovery, several factors have to be taken into account that significantly affect the patient’s motor activity and determine the pace and outcome of the rehabilitation process as a whole. Long-term, regular physical activity in patients with CHD with limited coronary reserve have an impact on the mechanisms of cardiac function regulation, synchronization and optimization of the activity of the muscular, cardiovascular and respiratory systems. Systematic training sessions reduce the volume of drug therapy and can improve the patients’ quality of life.
 Conclusions. The use of the proposed individualized uniform interval cycling training combined with the intake of citrulline malate leads to a significant improvement in the achieved load capacity, heart rate, duration of work, total volume of completed work, inotropic reserve index, optimization of coronary blood circulation and improvement of bioenergy metabolism in the myocardium.

NSFuzz: Towards Efficient and State-Aware Network Service Fuzzing

As an essential component responsible for communication, network services are security critical, thus, it is vital to find their vulnerabilities. Fuzzing is currently one of the most popular software vulnerability discovery techniques, widely adopted due to its high efficiency and low false positives. However, existing coverage-guided fuzzers mainly aim at stateless local applications, leaving stateful network services underexplored. Recently, some fuzzers targeting network services have been proposed but have certain limitations, for example, insufficient or inaccurate state representation and low testing efficiency. In this article, we propose a new fuzzing solution NSFuzz for stateful network services. We studied typical implementations of network service programs to determine how they represent states and interact with clients. Accordingly, we propose (1) a program variable–based state representation scheme and (2) an efficient interaction synchronization mechanism to improve fuzzing efficiency. We implemented a prototype of NSFuzz, which uses static analysis and annotation application programming interfaces (APIs) to identify synchronization points and state variables within the services. It then achieves fast I/O synchronization and accurate service state tracing to carry out efficient state-aware fuzzing via lightweight compile-time instrumentation. The evaluation results show that compared with other network service fuzzers, including AFL net and S tate AFL, our solution NSFuzz could infer a more accurate state model during fuzzing and improve fuzzing throughput by up to 200×. In addition, NSFuzz could improve code coverage by up to 25% and trigger more crashes in less time. We also performed a fuzzing campaign to find new bugs in the latest version of the target services; 8 zero-day vulnerabilities have been found by NSFuzz.

Isolation of the murine Glut1 deficient thalamocortical circuit: wavelet characterization and reverse glucose dependence of low and gamma frequency oscillations.

Glucose represents the principal brain energy source. Thus, not unexpectedly, genetic glucose transporter 1 (Glut1) deficiency (G1D) manifests with encephalopathy. G1D seizures, which constitute a prominent disease manifestation, often prove refractory to medications but may respond to therapeutic diets. These seizures are associated with aberrant thalamocortical oscillations as inferred from human electroencephalography and functional imaging. Mouse electrophysiological recordings indicate that inhibitory neuron failure in thalamus and cortex underlies these abnormalities. This provides the motivation to develop a neural circuit testbed to characterize the mechanisms of thalamocortical synchronization and the effects of known or novel interventions. To this end, we used mouse thalamocortical slices on multielectrode arrays and characterized spontaneous low frequency oscillations and less frequent 30-50 Hz or gamma oscillations under near-physiological bath glucose concentration. Using the cortical recordings from layer IV among other regions recorded, we quantified oscillation epochs via an automated wavelet-based algorithm. This method proved analytically superior to power spectral density, short-time Fourier transform or amplitude-threshold detection. As expected from human observations, increased bath glucose reduced the lower frequency oscillations while augmenting the gamma oscillations, likely reflecting strengthened inhibitory neuron activity, and thus decreasing the low:high frequency ratio (LHR). This approach provides an ex vivo method for the evaluation of mechanisms, fuels, and pharmacological agents in a crucial G1D epileptogenic circuit.

PATCH

Recent advancements in deep learning have shown that multimodal inference can be particularly useful in tasks like autonomous driving, human health, and production line monitoring. However, deploying state-of-the-art multimodal models in distributed IoT systems poses unique challenges since the sensor data from low-cost edge devices can get corrupted, lost, or delayed before reaching the cloud. These problems are magnified in the presence of asymmetric data generation rates from different sensor modalities, wireless network dynamics, or unpredictable sensor behavior, leading to either increased latency or degradation in inference accuracy, which could affect the normal operation of the system with severe consequences like human injury or car accident. In this paper, we propose PATCH, a framework of speculative inference to adapt to these complex scenarios. PATCH serves as a plug-in module in the existing multimodal models, and it enables speculative inference of these off-the-shelf deep learning models. PATCH consists of 1) a Masked-AutoEncoder-based cross-modality imputation module to impute missing data using partially-available sensor data, 2) a lightweight feature pair ranking module that effectively limits the searching space for the optimal imputation configuration with low computation overhead, and 3) a data alignment module that aligns multimodal heterogeneous data streams without using accurate timestamp or external synchronization mechanisms. We implement PATCH in nine popular multimodal models using five public datasets and one self-collected dataset. The experimental results show that PATCH achieves up to 13% mean accuracy improvement over the state-of-art method while only using 10% of training data and reducing the training overhead by 73% compared to the original cost of retraining the model.

The Design, Analysis, and Optimization of a New Pitch Mechanism for Small Wind Turbines

This article proposes and designs a novel variable pitch adjustment device for small wind turbines. The generator spindle is designed to be hollow so that the drive rod passes through it and connects the pitch drive mechanism to the pitch actuator. The article introduces the basic structure and working principle of the pitch mechanism and verifies the feasibility of the pitch device by using 3D printing technology to produce a small-scale model. The stress analysis of the wind turbine was carried out using the unidirectional fluid–structure coupling method. The results show that the maximum equivalent stress of the pitch mechanism is 27.42 MPa, the maximum tooth surface contact stress of the gear is 38.40 MPa, and the maximum tooth root bending stress is 18.13 MPa. The rack synchronous disk, blade handle, and gear rack mechanism were designed with light weight using various optimization schemes. The results of the optimization showed that the overall mass of the pitch mechanism was reduced by 33.2%, improving the applicability of the new pitch mechanism.

VDIU: VLC-Based Debugging Information Upload Method for Self-Powered Sensor Nodes

Currently, more and more self-powered sensor nodes have been deployed in remote and inaccessible areas, and thus online debugging of sensor nodes becomes more necessary and important. However, the existing sensor online debugging approaches mainly rely on original network infrastructure (such as Zigbee or NB-IoT). Once the communication infrastructure is invalid, it is almost impossible to retrieve debugging information and repair the lost self-powered sensor nodes. To this end, in our previous study, we employed the onboard optical modules of the self-powered sensor node to realize a Visible Light Communication(VLC)-based hybrid communication debugging system(VHCDS). In this paper, to improve the efficiency of uploading debugging information, we propose VDIU to optimize the digital pulse interval modulation applied in the uplink of VHCDS. This method reasonably groups and sorts the origin data to reduce the number of empty time slots (unused time slots) and complete data compression in source coding for saving energy. To improve the reliability of the uplink, we also design two frame synchronization mechanisms suitable for the receiver-side optical cameras of the uplink. One mechanism considers lightweight synchronization design via restricting the position of the frame header; the other one focuses on reducing the occupation of the downlink of VHCDS via predicting the position of the frame header using a temporal convolutional network (TCN). Experiments results illustrate that the upload efficiency using VDIU is higher 78% and 28% than DPIM and DH-PIM. Both synchronization mechanisms can arrive the similar performance, but the predicting mechanism reduces the 93% occupation on the downlink.

Hyperspectral Coherent Raman Scattering (CRS) Microscopy Based on a Rapidly Tunable and Environmentally Stable Fiber Laser

AbstractCoherent Raman scattering (CRS) microscopy is an attractive label‐free imaging method providing high chemical sensitivity, sub‐micron spatial resolution, and video‐rate imaging speed. When extended to hyperspectral CRS (HS‐CRS), it is capable of distinguishing molecules even in complex heterogeneous systems by probing multiple Raman resonances. Solid‐state lasers, associated with their high cost, large footprint, and slow tuning speed, currently limit the widespread application of HS‐CRS. Fiber lasers with comparable properties usually suffer from poor noise performance or instabilities during wavelength tuning. A tunable two‐color fiber laser is demonstrated that can be electronically tuned at rates of up to 1 kHz. The use of polarization‐maintaining fibers and an all‐optical synchronization mechanism guarantees its mode‐locking stability. The superior noise performance of this system is evaluated by the side‐by‐side comparison with data obtained by a commercial optical parametric oscillator (OPO)‐based laser. Large‐area multimodal imaging of liver tissue sections surgically resected from a patient suffering from a non‐neoplastic liver parenchyma with micronodular cirrhosis in combination with a multilocular hepatocellular carcinoma is demonstrated. By exploiting the fast‐hyperspectral scanning capability of the laser and multivariate statistical analysis, virtual staining of tissue sections and a comparison of the diagnostic properties of HS‐CRS to the classical histopathological approach are achieved.

Timing Matters: The Interplay between Early Mealtime, Circadian Rhythms, Gene Expression, Circadian Hormones, and Metabolism-A Narrative Review.

Achieving synchronization between the central and peripheral body clocks is essential for ensuring optimal metabolic function. Meal timing is an emerging field of research that investigates the influence of eating patterns on our circadian rhythm, metabolism, and overall health. This narrative review examines the relationship between meal timing, circadian rhythm, clock genes, circadian hormones, and metabolic function. It analyzes the existing literature and experimental data to explore the connection between mealtime, circadian rhythms, and metabolic processes. The available evidence highlights the importance of aligning mealtime with the body's natural rhythms to promote metabolic health and prevent metabolic disorders. Specifically, studies show that consuming meals later in the day is associated with an elevated prevalence of metabolic disorders, while early time-restricted eating, such as having an early breakfast and an earlier dinner, improves levels of glucose in the blood and substrate oxidation. Circadian hormones, including cortisol and melatonin, interact with mealtimes and play vital roles in regulating metabolic processes. Cortisol, aligned with dawn in diurnal mammals, activates energy reserves, stimulates appetite, influences clock gene expression, and synchronizes peripheral clocks. Consuming meals during periods of elevated melatonin levels, specifically during the circadian night, has been correlated with potential implications for glucose tolerance. Understanding the mechanisms of central and peripheral clock synchronization, including genetics, interactions with chronotype, sleep duration, and hormonal changes, provides valuable insights for optimizing dietary strategies and timing. This knowledge contributes to improved overall health and well-being by aligning mealtime with the body's natural circadian rhythm.

Design and Performance Testing of a Simulation Model for Time-Triggered Ethernet

Abstract Time-Triggered Ethernet (TTEthernet) is a new hybrid transmission network technology that introduces time-triggered, synchronization, and security mechanisms based on traditional Ethernet. It is difficult to verify the overall performance mechanism of the TTEthernet through manual calculation. Therefore, this paper models the TTEthernet End System and Switch, and simulates the overall performance of the TTEthernet Model based on the OPNET platform. Firstly, this paper introduces the key mechanisms and development status of the TTEthernet. Secondly, the simulation modeling of the TTEthernet End System and Switch are described, and the key technologies within the model are explained; The End system is an important component of the network, responsible for data generation, transmission, and processing. The Switch is responsible for data forwarding and routing, which plays a crucial role in the performance and stability of the network. Finally, the performance of the TTE network model in this article is analyzed through simulation data, verifying the timeliness, determinacy, and reliability of the model. Simulation data shows that the global throughput of the TTE network model in this article is stable at around 70Mbps, the End-to-End Delay of TT services is around 2.5ms, and the packet loss rate is almost zero, which meets the expected results. However, RC and BE services have higher end-to-end latency and packet loss rates than TT services due to their event triggered messages, but they still meet expectations.

An Improved Decentralized Control of Cascaded Inverters With Robust Stability Against Grid-Voltage Variation

The existing decentralized control method for grid-connected cascaded inverters has the problem that the system stability is sensitive to grid-voltage variation. As a result, the system would lose stability when the grid-voltage amplitude is abnormal. To address this issue, this letter proposes a novel decentralized -sin and V-P power control scheme. The robust stability condition against grid-voltage variation is proved. Moreover, the power-factor-angle consistency of inherent synchronization mechanism is clearly revealed for cascaded inverters, and the flexible grid power factor is enabled. For future practical applications, the proposed primary control of this letter explores a promising control idea for low-voltage cascaded PV/storage systems. Finally, the performance of the proposed method is compared with the existing method by simulations under small and large grid disturbances.

Integrated 3D genome, epigenomeand transcriptome analyses reveal transcriptional coordination of circadian rhythm in rice.

Photoperiods integrate with the circadian clock to coordinate gene expression rhythms and thus ensure plant fitness to the environment. Genome-wide characterization and comparison of rhythmic genes under different light conditions revealed delayed phase under constant darkness (DD) and reduced amplitude under constant light (LL) in rice. Interestingly, ChIP-seq and RNA-seq profiling of rhythmic genes exhibit synchronous circadian oscillation in H3K9ac modifications at their loci and long non-coding RNAs (lncRNAs) expression at proximal loci. To investigate how gene expression rhythm is regulated in rice, we profiled the open chromatin regions and transcription factor (TF) footprints by time-series ATAC-seq. Although open chromatin regions did not show circadian change, a significant number of TFs were identified to rhythmically associate with chromatin and drive gene expression in a time-dependent manner. Further transcriptional regulatory networks mapping uncovered significant correlation between core clock genes and transcription factors involved in light/temperature signaling. In situ Hi-C of ZT8-specific expressed genes displayed highly connected chromatin association at the same time, whereas this ZT8 chromatin connection network dissociates at ZT20, suggesting the circadian control of gene expression by dynamic spatial chromatin conformation. These findings together implicate the existence of a synchronization mechanism between circadian H3K9ac modifications, chromatin association of TF and gene expression, and provides insights into circadian dynamics of spatial chromatin conformation that associate with gene expression rhythms.

Heat-Driven Synchronization in Coupled Liquid Crystal Elastomer Spring Self-Oscillators.

Self-oscillating coupled machines are capable of absorbing energy from the external environment to maintain their own motion and have the advantages of autonomy and portability, which also contribute to the exploration of the field of synchronization and clustering. Based on a thermally responsive liquid crystal elastomer (LCE) spring self-oscillator in a linear temperature field, this paper constructs a coupling and synchronization model of two self-oscillators connected by springs. Based on the existing dynamic LCE model, this paper theoretically reveals the self-oscillation mechanism and synchronization mechanism of two self-oscillators. The results show that adjusting the initial conditions and system parameters causes the coupled system to exhibit two synchronization modes: in-phase mode and anti-phase mode. The work conducted by the driving force compensates for the damping dissipation of the system, thus maintaining self-oscillation. The phase diagrams of different system parameters are drawn to illuminate the self-oscillation and synchronization mechanism. For weak interaction, changing the initial conditions may obtain the modes of in-phase and anti-phase. Under conditions of strong interactions, the system consistently exhibits an in-phase mode. Furthermore, an investigation is conducted on the influence of system parameters, such as the LCE elastic coefficient and spring elastic coefficient, on the amplitudes and frequencies of the two synchronization modes. This study aims to enhance the understanding of self-oscillator synchronization and its potential applications in areas such as energy harvesting, power generation, detection, soft robotics, medical devices and micro/nanodevices.

DMPC-based string stable platoon control with robustness against communication delays

Communication delays are inevitable in vehicle platoons and may inhibit control performance. To address this issue, existing delay compensation strategies often resort to a greater time headway based on the delay upper bound, which compromises the benefits on traffic throughput. Moreover, it remains a major challenge to strictly ensure string stability with delays for distributed model predictive control (DMPC)-based controller. This paper presents a DMPC method for the cooperation of heterogeneous platoons subject to time-varying communication delays and greatly improves robustness against communication delays by improving the DMPC mechanism. A third-order heterogeneous vehicle dynamics model is integrated into the proposed method to improve control precision when implemented in the field. A synchronization mechanism is designed and the constant spacing policy is applied, which eliminates the delay dependence of the time headway selection and may thus improve traffic throughput. By incorporating a dual-mode scheme, a robustness constraint and a string stability constraint in the optimization problem, feasibility, closed-loop stability, and string stability are theoretically proved. A sufficient condition on the controller parameters is derived to guarantee closed-loop stability under communication delays. Numerical simulations are conducted to demonstrate the effectiveness of the proposed delay-compensating DMPC controller. The results reveal that the proposed controller outperforms the traditional DMPC controller and delay-involved linear controller on string stability, tracking performance and desired spacing selection.

An Energy Efficient Coherent IR-UWB Receiver With Non-Coherent-Assisted Synchronization

This paper presents a non-coherent assisted synchronization mechanism for low data rate coherent () receivers. A two-step coarse and fine acquisition mechanism is utilized to simplify the coherent synchronization and minimize the total required packet length. This hybrid scheme reduces the total power consumption of the receiver. The reception of a UWB packet begins with an energy efficient non-coherent synchronization portion in () modulation non-coherent acquisition. This reduces the search space for the coherent reception by first finding the best integration window that has the most energy of the received signal. Afterwards, the receiver searches coherently in () modulation within only the pre-selected integration window instead of the whole symbol time. Self-mixing and template-based correlation are utilized for the non-coherent and coherent reception, respectively. Most of the front-end blocks are shared between the coherent and non-coherent modes, including the LNA, mixer, and the baseband circuitry that follows to minimize the total power consumption of the receiver. A differential architecture including a (), a mixer, a fast start-up template generator, an integrator, and a differential comparator are utilized for the receiver front-end. A prototype of the proposed receiver operating from 3.5 to 5 GHz over four bands, each spaced by 500 MHz, is implemented in 65-nm CMOS technology. The proposed receiver architecture achieves a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 68 dBm, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 70.5 dBm, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 70.8 dBm sensitivity at a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-3}$</tex-math> </inline-formula> BER at 50 MHz () in the non-coherent, coherent, and proposed hybrid synchronization modes, respectively. The receiver consumes 6.8 mW and 8.8 mW in the non-coherent and coherent mode, respectively, when continuously ON. Using its novel synchronization mechanism, the receiver can reduce the ON time of the receiver by 68% and 34% in order to coherently synchronize and receive a 100-bit and 1024-bit payload, respectively. As a result, the () of the receiver is reduced by a factor of 2.9 from 1.24 nJ/b to 422 pJ/b for 100-bit payloads, and by a factor of 1.5 from 309 pJ/b to 204 pJ/b for 1024-bit payloads, increasing energy efficiency while maintaining the sensitivity benefits of coherent detection.