Design Of Heterogeneous Systems Research Articles

Oscillatory Neural Network-Based Ising Machine Using 2D Memristors.

Neural networks are increasingly used to solve optimization problems in various fields, including operations research, design automation, and gene sequencing. However, these networks face challenges due to the nondeterministic polynomial time (NP)-hard issue, which results in exponentially increasing computational complexity as the problem size grows. Conventional digital hardware struggles with the von Neumann bottleneck, the slowdown of Moore's law, and the complexity arising from heterogeneous system design. Two-dimensional (2D) memristors offer a potential solution to these hardware challenges, with their in-memory computing, decent scalability, and rich dynamic behaviors. In this study, we explore the use of nonvolatile 2D memristors to emulate synapses in a discrete-time Hopfield neural network, enabling the network to solve continuous optimization problems, like finding the minimum value of a quadratic polynomial, and tackle combinatorial optimization problems like Max-Cut. Additionally, we coupled volatile memristor-based oscillators with nonvolatile memristor synapses to create an oscillatory neural network-based Ising machine, a continuous-time analog dynamic system capable of solving combinatorial optimization problems including Max-Cut and map coloring through phase synchronization. Our findings demonstrate that 2D memristors have the potential to significantly enhance the efficiency, compactness, and homogeneity of integrated Ising machines, which is useful for future advances in neural networks for optimization problems.

Design and experiment of a sea-air heterogeneous unmanned collaborative system for rapid inspection tasks at sea

The incorporation of Unmanned Aerial Vehicles (UAVs) into sea surface inspection and complex water navigation tasks performed by Unmanned Surface Vessels (USVs) enhances the operational capabilities and task efficiency of heterogeneous systems. The autonomous docking of USV by UAV at sea serves as a foundational and vital element for facilitating collaborative tasks among unmanned systems. Faced with the problem that the UAV visual positioning USV deck is susceptible to interference from maritime meteorological conditions and the positioning accuracy of GPS is poor, this paper introduces the UWB positioning system and analyzes and solves the error disturbance term of its positioning array under the influence of sea sway for the first time. At the same time, due to the error problem caused by the small baseline of UWB installed on the deck, an adaptive Kalman filter that combines GPS speed information and UWB positioning data is proposed to reduce error. In light of the destabilizing effects resulting from the swaying of the USV deck during UAV docking, this study proposes a USV roll and pitch stability control strategy that incorporates environmental wind and wave data. Additionally, a UAV docking controller utilizing a fuzzy PID approach has been developed to facilitate secure and stable UAV takeoff and docking operations at sea. The effectiveness of the proposed algorithm was verified through sea docking experiments under various working conditions. Finally, in the context of the multi-target maritime inspection mission of heterogeneous unmanned systems, an exploratory improved VRP algorithm is proposed, allowing UAVs to quickly and efficiently complete sea surface inspection operations.The feasibility and operational efficiency of the cooperative mission system are tested through joint simulation using Simulink and UE4 in a high-fidelity environment. This provides a reference solution for future applications of heterogeneous unmanned systems in real maritime environments.

Hierarchical Porous Bimetallic FeMn Metal-Organic Framework Gel for Efficient Activation of Peracetic Acid in Antibiotic Degradation.

Effective techniques for eliminating antibiotics from water environments are in high demand. The peracetic acid (PAA)-based advanced oxidation process has recently drawn increasing attention for its effective antibiotic degrading capability. However, current applications of PAA-based techniques are limited and tend to have unsatisfactory performance. An additional catalyst for PAA activation could provide a promising solution to improve the performance of PAA. Bulky metal-organic framework gels (MOGs) stand out as ideal catalysts for PAA activation owing to their multiple advantages, including large surface areas, high porosity, and hierarchical pore systems. Herein, a bimetallic hierarchical porous structure, i.e., FeMn13BTC, was synthesized through a facile one-pot synthesis method and employed for PAA activation in ofloxacin (OFX) degradation. The optimized FeMn MOG/PAA system exhibited efficient catalytic performance, characterized by 81.85% OFX degradation achieved within 1 h owing to the specific hierarchical structure and synergistic effect between Fe and Mn ions, which greatly exceeded the performance of the only PAA-catalyzed system. Furthermore, the FeMn MOG/PAA system maintained >80% OFX degradation in natural water. Quenching experiments, electron spin resonance spectra, and model molecular degradation revealed that the primary reactive oxygen species responsible for the catalytic effect was R-O•, especially CH3C(=O)OO•, with minor contributions of •OH and 1O2. Overall, introduction of the MOG catalyst strategy for PAA activation achieved high antibiotic degradation performance, establishing a paradigm for the design of heterogeneous hierarchical systems to broaden the scope of catalyzed water treatment applications.

Trireme: Exploration of Hierarchical Multi-level Parallelism for Hardware Acceleration

The design of heterogeneous systems that include domain specific accelerators is a challenging and time-consuming process. While taking into account area constraints, designers must decide which parts of an application to accelerate in hardware and which to leave in software. Moreover, applications in domains such as Extended Reality (XR) offer opportunities for various forms of parallel execution, including loop level, task level, and pipeline parallelism. To assist the design process and expose every possible level of parallelism, we present Trireme , a fully automated tool-chain that explores multiple levels of parallelism and produces domain-specific accelerator designs and configurations that maximize performance, given an area budget. FPGA SoCs were used as target platforms, and Catapult HLS [ 7 ] was used to synthesize RTL using a commercial 12 nm FinFET technology. Experiments on demanding benchmarks from the XR domain revealed a speedup of up to 20×, as well as a speedup of up to 37× for smaller applications, compared to software-only implementations.

Heterogeneity Shifts the Storage-Computation Tradeoff in Secure Multi-Cloud Systems

This paper considers the design of heterogeneous multi-cloud systems for big data storage and computing in the presence of cloud collusion and failures. A fundamental concept of such a system is the secrecy capacity, which represents the maximum amount of information that can be stored for each unit of storage space under the requirements of secure distributed computing. A capacity-achieving code is designed for matrix multiplication, a computing subroutine widely used in machine learning applications. The code allows fast parallel decoding and unequal data allocation in the clouds. Such a flexibility leads naturally to the idea of optimizing data allocation to minimize the computing time. Given any feasible storage budget, the optimal solution is derived, characterizing explicitly the fundamental tradeoff between storage and computing. Furthermore, it is shown via majorization theory that the whole tradeoff curve improves if the cloud computing rates are more even. Experiments on Amazon EC2 clusters are conducted, corroborating our theoretical observations and the negligibility of decoding overhead.

Controlling the reactions of free radicals with metal-radical interaction

Radicals are key intermediates in numerous reactions. Their high reactivity enables various transformations to occur under mild conditions, however, also brings great challenges to control their reactions especially over heterogeneous catalysts. Here we propose to use metal nanoparticles to directly steer the conversion of free radical species. Results from photocatalytic reactions, in situ transient absorption spectroscopy, and theoretical simulation demonstrate that supported Pd nanoparticles can efficiently stabilize free radical species generated from photo-excited TiO2, and thus manipulate their conversion on catalyst surface, owing to the enhanced electronic interactions between metal and radical species. These understandings are crucial for the design of advanced heterogeneous catalytic systems with controllable radical reactions.

A-site defective La2-xCuO4 perovskite-type oxides for efficient oxidation of cyclohexylbenzene.

Phenol production through the oxidation of cyclohexylbenzene (CHB) and the subsequent decomposition of tertiary hydroperoxide has attracted more and more attention. In this study, defective La2-xCuO4 perovskite-type oxide catalysts with tunable A-site deficient structures and abundant surface oxygen vacancies were developed for the liquid phase oxidation of CHB to produce cyclohexylbenzene-1-hydroperoxide (CHBHP). By tuning the amount of A-site La ions in the perovskite structure, more surface oxygen vacancies and Cu+ species were formed in catalysts. The A-site-deficient La1.9CuO4 catalyst achieved significant catalytic efficiency along with a high CHBHP yield of 27.6% at 48.6% CHB conversion under reaction conditions (i.e., 120 °C and 12 h), outperforming those of other transition metal-based catalysts previously reported in the literature. A series of structural characterization methods and catalytic reactions highlighted the crucial roles of surface oxygen vacancies and metal La and Cu ions in the oxidation process. It was revealed that metal ions favored CHB adsorption and activation, while surface oxygen vacancies facilitated the creation of active adsorbed oxygen species. The present study offers an opportunity for the future design of new high-efficiency heterogeneous catalyst systems for CHB oxidation to obtain phenol.

On the catalytic vapor-phase dehydration of lactic acid to acrylic acid: a systematic review

This review gives an explicit overview of developments in the vapor-phase dehydration of lactic acid to acrylic acid with the rational design of heterogeneous catalyst systems. Constructive critiques are presented.

Movement Artifact Suppression in Wearable Low-Density and Dry EEG Recordings Using Active Electrodes and Artifact Subspace Reconstruction.

Wearable low-density dry electroencephalogram (EEG) headsets facilitate multidisciplinary applications of brain-activity decoding and brain-triggered interaction for healthy people in real-world scenarios. However, movement artifacts pose a great challenge to their validity in users with naturalistic behaviors (i.e., without highly controlled settings in a laboratory). High-precision, high-density EEG instruments commonly embed an active electrode infrastructure and/or incorporate an auxiliary artifact subspace reconstruction (ASR) pipeline to handle movement artifact interferences. Existing endeavors motivate this study to explore the efficacy of both hardware and software solutions in low-density and dry EEG recordings against non-tethered settings, which are rarely found in the literature. Therefore, this study employed a LEGO-like electrode-holder assembly grid to coordinate three 3-channel system designs (with passive/active dry vs. passive wet electrodes). It also conducted a simultaneous EEG recording while performing an oddball task during treadmill walking, with speeds of 1 and 2 KPH. The quantitative metrics of pre-stimulus noise, signal-to-noise ratio, and inter-subject correlation from the collected event-related potentials of 18 subjects were assessed. Results indicate that while treating a passive-wet system as benchmark, only the active-electrode design more or less rectified movement artifacts for dry electrodes, whereas the ASR pipeline was substantially compromised by limited electrodes. These findings suggest that a lightweight, minimally obtrusive dry EEG headset should at least equip an active-electrode infrastructure to withstand realistic movement artifacts for potentially sustaining its validity and applicability in real-world scenarios.

Dual H2O2 production paths over chemically etched MoS2/FeS2 heterojunction: Maximizing self-sufficient heterogeneous Fenton reaction rate under the neutral condition

Sufficient generation of H2O2 played an essential role in boosting self-sufficient heterogeneous Fenton reaction. Herein, the dual H2O2 production paths were designed to maximize the yield over H2O2-etched MoS2/FeS2 Z-scheme heterojunction, whose surface was modified with abundant –OH groups and sulfur vacancies (SVs). Mechanism studies revealed that H2O2 was generated via two-step single-electron reduction by electrons on conduction band, where H2O2 production was significantly improved by the internal hole-scavenging effect from –OH groups. Additionally, electrons surrounding SVs served as another sites for H2O2 production via one-step two-electron reduction even in darkness. H2O2 yield in neutral aqueous solution reached 1.5 mM/g/h without external hole scavenger. Tetracycline and rhodamine B were effectively degraded under light or in darkness. The degradation performance was even comparable to the heterogeneous Fenton reaction. This work provides new insights for the design of self-sufficient heterogeneous Fenton system with exceptional degradation performance.

Enhancing the performance of asymmetric architectures and workload characterization using LSTM learning algorithm

Asymmetric multiple core architectures are becoming increasingly popular because of their QoS, energy efficiency, and high performance. Because of the heterogeneous piping layout and execution procedure, the overall system performance is highly influenced by workload characterization becomes a difficult issue. Recently, it has become vital to create a performance evaluator for faster response FPGA structures. With the embedded computerized visual hardware resources (e.g. GPUs, FPGAs, and multi-core CPUs) and its associated software manages this heterogeneous system design is tough for the researchers. A thorough analysis of the performance of run-time and various embedded kernels' energy efficiencies to assist developers in determining which embedded substrate is best for their project. To solve these challenges, resource-based prediction models are developed for FPGA-SoC relying on the characterization of intellectual workload, and its performance is thoroughly examined. Xilinx FPGA frameworks are used to run a variety of real-time applications that perform workloads depending on projected processing cores. When compared to existing Ml classifiers, this LSTM predictor achieves a mean of 96% of the experimental findings and also improves energy efficiency.

Design of heterogeneous time-lags system with multi-stability and its analog circuit

A novel heterogeneous time-lags chaotic system is constructed and explored in this work. By choosing appropriate control parameters, the state of this system can be switched between conservative and dissipative. When different initial conditions are selected, this system can produce multiple coexisting attractors or flows, that is, the system has the property of multi-stability. More interestingly, the attractors generated by this system can be distributed in 1-D lines, 2-D lattices and 3-D grids which means the circumstance of multi-directional attractors occurs. And the rare phenomenon of transient chaos is analyzed in this system as well. It is worth noting that the implementation of hardware circuits for time-lags chaotic systems has been a major obstacle in engineering applications. To remove this bottleneck and further explore the physical presence of this proposed system, the hardware analog circuit of the proposed system is achieved. The experimental observations further verify the feasibility of this system. Additionally, the experiments of spectral entropy complexity and image encryption performance verify the good performance of the proposed system.

Towards Full‐spectrum Photocatalysis: Extending to the Near‐infrared Region

AbstractThe ability to use the full solar spectrum energy in photocatalytic processes for environmental remediation and energy production has attracted worldwide attention. Efficient harvesting of near‐infrared (NIR) photons, especially in the wavelength range beyond 800 nm, is one of the main driving forces in photocatalytic research. The design of appropriate photocatalytic systems for wide‐range light‐harvesting from the UV to NIR regions is a promising method of maximizing the efficiency of solar energy utilization. This review comprehensively summarizes the recent progress in full‐solar‐light‐driven photocatalytic systems, including several strategies to harness NIR light and thermal energy. The corresponding photocatalytic mechanisms and design of binary or ternary heterogeneous systems are discussed in detail. Moreover, future perspectives and challenges are presented to inspire the development of further innovations in full‐solar‐light‐driven photocatalysis.

High Throughput Hardware/Software Heterogeneous System for RRPN-Based Scene Text Detection

Rotation Region Proposal Networks (RRPN) are used to generate rotated proposals with the information of text angle for arbitrary oriented scene text detection (STD). However, the computational complexity of RRPN inference is relatively high compared with other methods, which makes it difficult for massive deployment. In this paper, the first full-stack FPGA-CPU heterogeneous system design of RRPN-based STD algorithm is proposed. A hardware/software partition method is presented to analyze and split the tasks to enhance the computation efficiency of hardware. The fast 2D Winograd algorithm and block floating point are utilized to reduce computation complexity while maintaining a relatively high precision. The implementation results show that the peak performance of MAC arrays in the proposed architecture reaches 655.4 GOPS and the energy efficiency achieves 64.9 GOPS/W. By fully exploiting the parallel and pipelined merits in the algorithms, the first hardware architectures for skew non-maximum suppression (S-NMS) layer and rotation region-of-interest (RRoI) polling layer are proposed. The throughput of the proposed hardware/software heterogeneous system achieves 40 times and 1.4 times improvements compared with CPU and GPU, respectively. Moreover, the comprehensive operating expense ratio of pure CPU, GPU, and the proposed system is 80.7:2.5:1, which indicates that it is suitable for massive deployment.

Design of Heterogeneous Cyber-Physical Systems Employing Category Theory

Heterogeneous cyber-physical control systems based on digital twins are in demand by Industry 4.0. In accordance with the contemporary systems engineering methodology, such systems are designed at the level of digital models. The paper proposes approaches to formalization and subsequent automation of solving direct and inverse problems of their design. To unify descriptions of heterogeneous components, we follow a viewpoint-based approach to architecture design recommended by the international standard ISO/IEC/IEEE 42010. Following recent trends, we employ category theory as a mathematical framework for the formal description and solution of design problems. Indeed, category theory is a branch of higher algebra specifically aimed at a unified representation of objects of different nature and relationships between them. The design space of a heterogeneous cyber-physical system is constructed as a subcategory of the multicomma category, the objects of which describe possible system architectures with a fixed structural hierarchy represented from a certain viewpoint as diagrams, and morphisms denote actions associated with the parts selection and replacement during the system design. Direct design problems consist in evaluating the properties of the system as a whole by its architecture and are solved using a universal category-theoretic construction of the colimit of the diagram. The solution of inverse problems that require finding variants of the system architecture, which are (sub-, Pareto-) optimal according to the consumer quality criteria, consists in reconstructing diagrams by their colimit edges. For such reconstruction, optimization algorithms of gradient descent type are reasonable to employ, which navigate along the system design space morphisms calculating the path by means of computer algebra. Typical techniques of assembling cyber-physical systems, such as modular composition and aspect weaving, are described in the language of category theory and illustrated. As an example, we outline the design of energy-efficient robotic production lines represented from the behavior viewpoint as discrete-event simulation models.

Honeycomb-like holey Co3O4 membrane triggered peroxymonosulfate activation for rapid degradation of organic contaminants

Heterogeneous advanced oxidation processes (AOPs) are commonly employed for the degradation of recalcitrant contaminants, however, practical application of heterogeneous AOPs has been limited by their low activation efficiency and inefficient utilization of radicals. Herein, this study demonstrates for the first time that 2D honeycomb-like holey membranes assembled by Co3O4 nanosheets, serve as an excellent activator for peroxymonosulfate (PMS) and aid in rapid pollutant removal. The Co3O4 membrane achieved 100% target pollutant ranitidine removal and a membrane retention time of only ~385 ms with the degradation rate 3–5 orders of magnitude faster than that achieved by conventional heterogeneous catalysis. Ranitidine degradation was maintained at >90% for 13 h of continuous-flow operation at a high flux of 176 L m−2 h−1 bar−1. Furthermore, the Co3O4 membrane could also effectively degrade several recalcitrant pollutants, including pharmaceutical personal care products, phenols, and dyes. SO4•– and •OH were identified as the primary reactive oxygen species in the Co3O4 membrane/PMS system, with Co providing the active site for PMS activation. This strategy of membrane-based AOP treatment offers helpful guidance for the design of other efficient heterogeneous catalytic systems and presents a novel approach to overcoming the limitations of conventional heterogeneous catalysis.

RETRACTED ARTICLE: Design of Heterogeneous Data Transmission System for Industrial Enterprises Based on Fuzzy Algorithm

The traditional heterogeneous data transmission system of industrial enterprises has poor performance. In order to solve this problem, the design of heterogeneous data transmission system of industrial enterprises based on fuzzy algorithm is proposed. The hardware of the system is composed of STM32F107RCt6 microprocessor, FLASH memory, AS32-TTL-100 wireless module and DP83848x chip, which realizes the hardware design of two node functions. The system software introduces the fuzzy algorithm to realize the data transmission function, including data source management module, data extraction module, data writing module, log management module and user management module. The design of heterogeneous data transmission system of industrial enterprise based on fuzzy algorithm is completed by combining software and hardware. Finally, enter the experimental part to test the performance of the proposed system and the traditional system. The experimental results show that the performance of the proposed system is better, further play the role of information data in production; improve system efficiency and anti-fault ability.

Design of a high-stability heterogeneous clock system for small satellites in LEO

We describe our investigation into the performance of low-power heterogeneous timing systems for small satellites, using real GPS observables from the GRACE Follow-On mission. Small satellites have become capable platforms for a wide range of commercial, scientific and defense missions, but they are still unable to meet the needs of missions that require precise timing, on the order of a few nanoseconds. Improved low-power onboard clocks would make small satellites a viable option for even more missions, enabling radio aperture interferometry, improved radio occultation measurements, high altitude GPS navigation, and GPS augmentation missions, among others. One approach for providing improved small satellite timekeeping is to combine a heterogeneous group of oscillators, each of which provides the best stability over a different time frame. A hardware architecture that uses a single-crystal oscillator, one or more Chip Scale Atomic Clocks (CSACs) and the reference time from a GPS receiver is presented. The clocks each contribute stability over a subset of timeframes, resulting in excellent overall system stability for timeframes ranging from less than a second to several days. A Kalman filter is used to estimate the long-term errors of the CSACs based on the CSAC-GPS time difference, and the improved CSAC time is used to discipline the crystal oscillator, which provides the high-stability reference clock for the small satellite. Simulations using GRACE-FO observations show time error standard deviations for the system range from 2.3 ns down to 1.3 ns for the clock system, depending on how many CSACs are used. The results provide insight into the timing performance which could be achieved on small LEO spacecraft by a low power timing system.

Synthesis and characterization of chitosan-supported Fe2O3 nanohybrids for rapid sonophotocatalytic degradation of 2,4,6-trichlorophenol.

The present study reports the design of heterogeneous photocatalytic system using Fe2O3 with chitosan (CS) as a matrix for the sonophotocatalytic degradation of 2,4,6-trichlorophenol (2,4,6-TCP). CS was chosen as a polymer matrix as it is abundant in nature, eco-friendly, and can be easily processed into microparticles, nanofibers, as well as nanoparticles and shows the tendency of adhesion towards a vast range of solid substrates besides serving as a chelating agent toward metallic oxides. The nanohybrids were characterized via Fourier transformation infrared spectrum (FT-IR), X-ray diffraction (XRD), scanning electron microscopy coupled with electron dispersive spectrum (SEM-EDS), thermogravimetric analysis (TGA), and UV-visible diffuse reflectance (UV-Vis-DRS) analyses. Infrared spectroscopy (IR) studies confirmed synergistic interaction between Fe2O3 and CS. The XRD measurements confirmed the crystalline morphology while SEM revealed formation of rod-like structures. The TGA studies confirmed higher thermal stability of CS/Fe2O3 as compared to pure CS. The optical band gap for CS and CS/Fe2O3 was calculated to be 3 eV and 2.25 eV, respectively, from diffuse reflectance spectral (DRS) studies. Rapid photocatalytic degradation of 2,4,6-TCP was observed under UV light irradiation in presence of CS and CS/Fe2O3 nanohybrids which revealed 83.19% and 95.20% degradation within a short span of 60 min. The degraded fragments were identified using liquid chromatography-mass spectrometry (LC-MS). The present study on the development of ecofriendly nanohybrid photocatalyst is expected to provide experimental basis for the future development of CS-based photocatalysts which can be easily processed into membranes/filters for the industrial scale degradation of toxic organic pollutants.

Recent Progress in Designing Halide-Perovskite-Based System for the Photocatalytic Applications.

The halide perovskite material has attracted vast attention as a versatile semiconductor in the past decade. With the unique advantages in physical and chemical properties, they have also shown great potential in photocatalytic applications. This review aims at the specific design principles triggered by the unique properties when employing halide-perovskite-based photocatalytic systems from the following perspectives: (I) Design of photoelectrocatalytic device structures including the n-i-p/p-i-n structure, photoelectrode device encapsulation, and electrolyte engineering. (II) The design of heterogeneous photocatalytic systems toward the hydrogen evolution reaction (HER) and CO2 reduction reaction, including the light management, surface/interface engineering, stability improvement, product selectivity engineering, and reaction system engineering. (III) The photocatalysts for the environmental application and organic synthesis. Based on the analyses, the review also suggests the prospective research for the future development of halide-perovskite-based photocatalytic systems.